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Sample records for newt notophthalmus viridescens

  1. Maintaining Eastern newts (Notophthalmus viridescens) for regeneration research.

    PubMed

    Simon, Hans-Georg; Odelberg, Shannon

    2015-01-01

    The adult Eastern newt, Notophthalmus viridescens, has long served as a model for appendage as well as heart muscle regeneration studies. Newt tissues include all major cell types known in other vertebrates and mammals, including bone, cartilage, tendon, muscle, nerves, dermis, and epidermis. Therefore, these aquatic salamanders make an excellent model for studying the regeneration of complex tissues. Regeneration of adult tissues requires the integration of new tissues with preexisting tissues to form a functioning unit through a process that is not yet well understood. Scale is also an issue, because the regenerating tissues or structures are magnitudes larger than their embryonic counterparts during development, and therefore, it is likely that different physics and mechanics apply. Regardless, regeneration recapitulates to some degree developmental processes. In this chapter, we will describe basic methods for maintaining adult Eastern newts in the laboratory for the study of regeneration. To determine similarities and differences between development and regeneration at the cellular and molecular level, there is also a need for embryonic newt tissue. We therefore also outline a relatively simple way to produce and raise newt embryos in the laboratory.

  2. Tetrodotoxin does not protect red-spotted newts, Notophthalmus viridescens, from intestinal parasites.

    PubMed

    Mebs, Dietrich; Yotsu-Yamashita, Mari; Seitz, Hanns Martin; Arakawa, Osamu

    2012-07-01

    Tetrodotoxin (TTX) and its analogue 6-epiTTX had been detected in the red-spotted newt, Notophthalmus viridescens. Thirty specimens of a population from Pennsylvania, USA were histologically examined for the presence of intestinal parasites. More than 50% were found to be infected with nematodes (Trichocephalidae), trematodes or cestodes (Pseudophyllidae). The mean values of TTX and 6-epiTTX in parasitized and in non-parasitized newts were not significantly different. Using a monoclonal antibody-based immunoenzymatic technique, TTX was localized in the intestinal tissue as well as in the parasites indicating that they accumulate the toxin and suggesting that TTX and 6-epiTTX are not providing protection from parasites to the newts.

  3. Temperature preference during forelimb regeneration in the red-spotted newt Notophthalmus viridescens.

    PubMed

    Tattersall, Glenn J; Tyson, Teala M; Lenchyshyn, Jessika R; Carlone, Robert L

    2012-04-01

    Red-spotted newts (Notophthalmus viridescens) are model organisms for regenerative research. These animals can regenerate limbs, tails, jaws, spinal cords, as well as the lens of the eye. Newts are small ectotherms that are aquatic as adults; as ectotherms, they naturally conform to the temperature of their surroundings. Environmental temperatures, however, can increase or decrease the red-spotted newt's metabolic processes, including their rate of tissue regeneration; whether an optimal temperature for this rate of regeneration exists is unknown. However, newts do exhibit behavioral preferences for certain temperatures, and these thermal preferences can change with season or with acclimation. Given this flexibility in behavioral thermoregulation, we hypothesized that the process of tissue regeneration could also affect thermal preference, given the metabolic costs or altered temperature sensitivities of tissue regrowth. It was predicted that regenerating newts would select an environmental temperature that maximized the rate of regeneration, however, this prediction was not fully supported. Thermal preference trials revealed that newts consistently selected temperatures between 24 and 25°C throughout regeneration. This temperature selection was warmer than that of uninjured conspecifics, but was lower than temperatures that would have further augmented the rate of regeneration. Interestingly, regenerating newts maintained a more stable temperature preference than sham newts, suggesting that accuracy in thermoregulation may be more important to regenerating individuals, than to noninjured individuals.

  4. Magnetic compass orientation in the Eastern red-spotted newt (Notophthalmus viridescens).

    PubMed

    Phillips, J B

    1986-01-01

    Laboratory tests were carried out to examine the orientation behavior of adult Eastern red-spotted newts (Notophthalmus viridescens) to earth-strength magnetic fields. Groups of 30 to 40 newts were housed in water-filled, all-glass aquaria with an artificial shoreline at one end. The aquaria were located in a greenhouse or outdoors adjacent to the laboratory building, and aligned on either the magnetic north-south or east-west axis. Tests were carried out in an enclosed indoor arena. Newts were tested in four horizontal alignments of the magnetic field: the ambient magnetic field (magnetic north at North) and three altered fields (magnetic north rotated to East, South or West). Data were analyzed after pooling the magnetic bearings from all four conditions in such a way as to retain the component of the newts' orientation that was a consistent response to the magnetic field. Elevation of training tank water temperature was used to increase the newts' motivation to orient in the direction of shore. Newts exposed to a training tank water temperature of 33-34 degrees C just prior to testing exhibited consistent unimodal magnetic compass orientation. The direction of orientation was altered predictably by changing training tank alignment and location relative to the laboratory building. The results provide the first evidence of a strong, replicable magnetic compass response in a terrestrial vertebrate under controlled laboratory conditions. Further, the present study demonstrates that the Eastern newt is able to learn a directional response relative to the earth's magnetic field.

  5. Laboratory studies of homing orientation in the eastern red-spotted newt, Notophthalmus viridescens.

    PubMed

    Phillips, J B

    1987-09-01

    The orientation behaviour of adult male eastern red-spotted newts (Notophthalmus viridescens) was studied in laboratory tests. Newts were collected from ponds located 10-30 km from the laboratory, and housed in water-filled, all-glass aquaria located in a greenhouse or outdoors adjacent to the laboratory building. The aquaria were aligned on the magnetic north-south axis. Newts were tested in a dry, enclosed arena in four magnetic fields: the ambient magnetic field (magnetic north at North) and three altered fields (magnetic north rotated to East, West or South). Newts tested during January-March exhibited weak bimodal magnetic orientation along the axis of the holding tank. However, during the spring migratory period (April until early May), the bimodal response shifted to coincide with the direction of the pond from which the newts had been collected. Much stronger unimodal orientation was elicited by elevating the water temperature to 33-34 degrees C immediately prior to testing. If newts were held in a training tank with an artificial shoreline at one end and exposed to elevation of water temperature after several days of stable water temperatures, they exhibited unimodal shoreward orientation and did not show the seasonal switch to homing behaviour observed in the earlier tests. If, however, the elevation of water temperature followed a period of fluctuating water temperature (over a 20 degrees C range), the newts exhibited strong unimodal orientation in the direction of the pond from which they had been collected. These results suggest that newts possess a navigational system that enables them to home from distances in excess of 20 km. Moreover, these experiments provide the first opportunity to examine the sensory basis of navigational ability in any animal under controlled laboratory conditions.

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

    USGS Publications Warehouse

    Smith, Kimberly G.

    2006-01-01

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

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

    PubMed

    Smith, Kevin G

    2006-06-01

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

  8. Toxicity of coal-tar and asphalt sealants to eastern newts, Notophthalmus viridescens.

    PubMed

    Bommarito, Thomas; Sparling, Donald W; Halbrook, Richard S

    2010-09-01

    Between 1970 and 2000 the concentration of total polycyclic aromatic hydrocarbons (TPAH) in several lakes across the country increased whereas those of other persistent organic pollutants (POPs) tended to remain stable or declined. Urbanized watersheds experienced greater rises in TPAH concentration compared to non-urban lakes. Sources for urban PAHs include industrial wastes, vehicular exhausts and oil leaks and sealants from pavement surfaces. Both coal-tar and asphalt sealants are used to protect surfaces but runoff from surfaces coated with coal-tar can have mean concentrations of 3500 mg TPAHs kg(-1), much higher than runoff from asphalt-sealed or cement surfaces. Unaltered parent compounds of PAHs can have many lethal and sublethal toxic effects, but oxidation and UV radiation can alter the toxicity of these compounds, sometimes creating degradates that are many times more toxic than parent compounds. The purposes of this study were to determine if coal-tar sealants can be toxic to adult eastern newts (Notophthalmus viridescens) and to compare the toxicity of coal-tar sealant to that of asphalt sealant. Newts were exposed to sediments containing dried sealants ranging from 0 mg kg(-1) to 1500 mg kg(-1) under simultaneous exposure to UV radiation and visible light to determine concentration/response relationships. No significant mortality occurred with any treatment. Significant effects due to sealants included decreased righting ability and diminished liver enzyme activities. Coal-tar sealant was more effective in inducing these changes than was asphalt sealant. PMID:20696464

  9. Does the thermal plasticity of metabolic enzymes underlie thermal compensation of locomotor performance in the eastern newt (Notophthalmus viridescens)?

    PubMed

    Mineo, Patrick M; Schaeffer, Paul J

    2015-01-01

    Eastern newts (Notophthalmus viridescens) upregulate the metabolic capacity of skeletal muscle in winter to compensate for thermodynamic effects on metabolism. However, whether this compensation facilitates locomotor performance at low temperature is unknown. Therefore, our aim was to determine if thermal acclimation of metabolic enzymes in muscle benefits locomotion. Eastern newts from southern Ohio were acclimated to cold (5°C, 10:14 L:D) or warm (25°C, 14:10 L:D) conditions for 12 weeks. Following acclimation, we measured the locomotor performance (burst speed and time until exhaustion) and the activities of metabolic enzymes in skeletal muscle at 5-30°C. Creatine kinase (CK) activity in skeletal muscle was higher in cold compared to warm-acclimated newts, and cold-acclimated newts had a higher burst speed at low temperature compared to warm-acclimated newts. At low temperature, time until exhaustion was higher in cold compared to warm-acclimated newts, but the activities of citrate synthase (CS) and cytochrome c oxidase (CCO) in muscle were lower in cold compared to warm-acclimated newts. Together, these results demonstrate that eastern newts compensate for the effects of low temperature on locomotor performance. Whereas thermal compensation of CK activity is correlated with burst locomotion at low temperature, aerobic enzymes in skeletal muscle (CS and CCO) are not linked to compensation of sustained locomotion.

  10. Chemical defense of the eastern newt (Notophthalmus viridescens): variation in efficiency against different consumers and in different habitats.

    PubMed

    Marion, Zachary H; Hay, Mark E

    2011-01-01

    Amphibian secondary metabolites are well known chemically, but their ecological functions are poorly understood--even for well-studied species. For example, the eastern newt (Notophthalmus viridescens) is a well known secretor of tetrodotoxin (TTX), with this compound hypothesized to facilitate this salamander's coexistence with a variety of aquatic consumers across the eastern United States. However, this assumption of chemical defense is primarily based on observational data with low replication against only a few predator types. Therefore, we tested the hypothesis that N. viridescens is chemically defended against co-occurring fishes, invertebrates, and amphibian generalist predators and that this defense confers high survivorship when newts are transplanted into both fish-containing and fishless habitats. We found that adult eastern newts were unpalatable to predatory fishes (Micropterus salmoides, Lepomis macrochirus) and a crayfish (Procambarus clarkii), but were readily consumed by bullfrogs (Lithobates catesbeianus). The eggs and neonate larvae were also unpalatable to fish (L. macrochirus). Bioassay-guided fractionation confirmed that deterrence is chemical and that ecologically relevant concentrations of TTX would deter feeding. Despite predatory fishes rejecting eastern newts in laboratory assays, field experiments demonstrated that tethered newts suffered high rates of predation in fish-containing ponds. We suggest that this may be due to predation by amphibians (frogs) and reptiles (turtles) that co-occur with fishes rather than from fishes directly. Fishes suppress invertebrate consumers that prey on bullfrog larvae, leading to higher bullfrog densities in fish containing ponds and thus considerable consumption of newts due to bullfrog tolerance of newt chemical defenses. Amphibian chemical defenses, and consumer responses to them, may be more complex and indirect than previously appreciated. PMID:22164212

  11. Chemical defense of the eastern newt (Notophthalmus viridescens): variation in efficiency against different consumers and in different habitats.

    PubMed

    Marion, Zachary H; Hay, Mark E

    2011-01-01

    Amphibian secondary metabolites are well known chemically, but their ecological functions are poorly understood--even for well-studied species. For example, the eastern newt (Notophthalmus viridescens) is a well known secretor of tetrodotoxin (TTX), with this compound hypothesized to facilitate this salamander's coexistence with a variety of aquatic consumers across the eastern United States. However, this assumption of chemical defense is primarily based on observational data with low replication against only a few predator types. Therefore, we tested the hypothesis that N. viridescens is chemically defended against co-occurring fishes, invertebrates, and amphibian generalist predators and that this defense confers high survivorship when newts are transplanted into both fish-containing and fishless habitats. We found that adult eastern newts were unpalatable to predatory fishes (Micropterus salmoides, Lepomis macrochirus) and a crayfish (Procambarus clarkii), but were readily consumed by bullfrogs (Lithobates catesbeianus). The eggs and neonate larvae were also unpalatable to fish (L. macrochirus). Bioassay-guided fractionation confirmed that deterrence is chemical and that ecologically relevant concentrations of TTX would deter feeding. Despite predatory fishes rejecting eastern newts in laboratory assays, field experiments demonstrated that tethered newts suffered high rates of predation in fish-containing ponds. We suggest that this may be due to predation by amphibians (frogs) and reptiles (turtles) that co-occur with fishes rather than from fishes directly. Fishes suppress invertebrate consumers that prey on bullfrog larvae, leading to higher bullfrog densities in fish containing ponds and thus considerable consumption of newts due to bullfrog tolerance of newt chemical defenses. Amphibian chemical defenses, and consumer responses to them, may be more complex and indirect than previously appreciated.

  12. Variability of tetrodotoxin and of its analogues in the red-spotted newt, Notophthalmus viridescens (Amphibia: Urodela: Salamandridae).

    PubMed

    Yotsu-Yamashita, Mari; Gilhen, John; Russell, Ronald W; Krysko, Kenneth L; Melaun, Christian; Kurz, Alexander; Kauferstein, Silke; Kordis, Dusan; Mebs, Dietrich

    2012-02-01

    Efts and adult specimens (n = 142) of the red-spotted newt Notophthalmus viridescens from various locations in Canada and USA were analyzed for the presence of tetrodotoxin (TTX) and of its analogues 6-epitetrodotoxin and 11-oxotetrodotoxin. Considerable individual variations in toxin levels were found within and among populations from New Hampshire, New York, Pennsylvania, and Virginia ranging from non-detectable to 69 μg TTX per g newt. TTX and its analogues were absent in efts and adults from various locations in the Canadian province Nova Scotia, the northernmost distribution of the newt, and in adults from Florida. Newts kept in captivity for several years and reared on toxin-free diet lost their toxicity. Bayesian and maximum likelihood phylogenetic analysis of specimens from the various populations using three phylogenetic markers (COI, ND2 and 16S RNA) revealed that populations from the northern states of the USA and Canada are genetically homogenous, whereas the newts from Florida exhibited a much higher level of genetic divergence. An exogenous source of TTX in the newts either via the food chain or by synthesis of symbiotic bacteria is suggested to explain the high variability and lack of TTX in certain populations.

  13. The thermal plasticity of locomotor performance has diverged between northern and southern populations of the eastern newt (Notophthalmus viridescens).

    PubMed

    Mineo, Patrick M; Schaeffer, Paul J

    2015-01-01

    Many temperate ectotherms undergo thermal acclimation to remain functional over a wide range of body temperatures, but few studies have investigated whether populations of a single species have evolved differences in the thermal plasticity of locomotor performance. Therefore, we asked whether the thermal plasticity of locomotor performance has diverged between northern and southern populations of eastern newts (Notophthalmus viridescens). We acclimated eastern newts from Florida and Maine to cold (6 °C) or warm (28 °C) conditions for 12 weeks. Following acclimation, we measured the burst speed of newts at 6, 11.5, 17, 22.5, 28, and 33.5 °C. We also measured the activities of creatine kinase (CK) and lactate dehydrogenase (LDH) in skeletal muscle of newts. The newts from Maine were better able to acclimate to low temperature compared to newts from Florida. Regardless of acclimation, the thermal sensitivity of burst speed was higher in the Florida compared to the Maine population. In general, newts from Maine performed better at low temperatures, whereas newts from Florida performed better at high temperatures. The activities of CK and LDH were lower in cold compared to warm-acclimated newts in the Florida population, but acclimation did not affect the activities of these enzymes in the Maine population. The activities of CK and LDH do not explain differences in the thermal plasticity of locomotor performance between populations. Our results demonstrate that the thermal sensitivity and plasticity of locomotor performance differ between northern and southern populations of eastern newts, suggesting that these traits readily adapt to the thermal environment.

  14. Localization of 5'-ribonucleotide phosphohydrolase in regenerating (and normal) limb tissues of the adult newt Notophthalmus viridescens.

    PubMed

    Schmidt, A J; Woerthwein, K F

    1975-08-11

    The regenerating forelimb of the adult newt, Notophthalmus viridescens was investigated for 5'-nucleotidase (5' ribonucleotide phosphohydrolase, 3.1.3.5) acitivity. The newt's humeri were surgically removed, and after a twenty-one-day recovery period, the forelimbs amputated above the elbows. Regenerates were sampled at predetermined times for specific phases in the progress of regeneration, frozen, sectioned in a cryostat, and the sections fixed in 10% cold formol calcium. The Wachstein and Meisel [25] lead procedure at neutral pH was used predominately in these experiments, although tests were also conducted with Gomori's [14] calcium, Allen's [21] highly alkaline procedures. The substrates used to obtain specific enzyme reactions were adenine, cytosine, guanine, uracil and inosine 5'-monophosphate nucleotides. Sodium beta-glycerophosphate served as a non-specific phosphomonoesterase substrate, distilled water replaced substrate, and inhibitors such as zinc and cyanide ions were used as control measures to assist in increasing the precision in interpreting the results obtained. The most reactive 5'-nucleotidase (5'-Nase) loci were in the walls of the blood vascular system, mysial and neural sheaths, dermis, and periosteum: the principal cells involved were macrophages, endothelium of blood vessels, and fibrocytes of connective tissues. A moderate enzyme response was elicited from secretory cells of some of the subcutaneous glands, hypertrophied chondrocytes and osteogenic centers, chondrocytes in the articular regions and within red blood cells and leucocytes. Normal, injured and degenerating, or regenerating striated muscle and nerve fibers were judged unreactive for 5'-Nase. The epidermis and wound epithelium displayed negative responses for 5'-Nase. Cells forming the regeneration blastema were 5'-Nase reactive during the early formative phase, but with growth and development of the blastema into bulb and conic forms, these cells did not respond for this enzyme

  15. Exogenous Oct-4 inhibits lens transdifferentiation in the newt Notophthalmus viridescens.

    PubMed

    Bhavsar, Rital B; Tsonis, Panagiotis A

    2014-01-01

    From the cocktail of four factors that were able to induce pluripotent stem cells from differentiated cells, Oct-4, c-Myc, Sox-2 and Klf4, only Oct-4 was not expressed during regeneration in newts. To explore the possible action of this stemness factor we developed an assay where we introduced exogenous Oct-4 protein to an in vitro system for lens regeneration in newts. We found that exogenous Oct-4 inhibits differentiation of iris pigmented epithelial cells into lens cells and also regulates Sox-2 and Pax-6, both important players during lens development. Thus, presence of Oct-4 hinders transdifferentiation of iris cells.

  16. A new species of Hysterothylacium (Nematoda: Anisakidae) from the stomach of the red-spotted newt, Notophthalmus viridescens, from Pennsylvania fishless ponds.

    PubMed

    Raffel, Thomas R; Anderson, Tavis K

    2009-12-01

    Species of Hysterothylacium Ward & Magath, 1917 (Nematoda: Anisakidae) have previously been reported only from marine and freshwater fishes. Here, we describe a new species that infects red-spotted newts (Notophthalmus viridescens), a North American amphibian species with fully aquatic adults. Aside from the unique characteristic of infecting an amphibian host, the new species differs from congeners by the presence of lateral alae, the length of intestinal cecum (0.54–0.73 mm, 39.67–49.09% of esophageal length), the size of the spicules (0.33–0.39 mm, 2.75–3.25% of body length), and the absence of tail tip ornamentation. The absence of fish in the ponds from which these specimens were obtained suggests that newts are the normal definitive host for this species. We suggest that this species might have diverged from a Hysterothylacium parasite of the freshwater fishes which usually live in close proximity with newts. PMID:19473051

  17. An acute increase in the stress hormone corticosterone is associated with mating behavior in both male and female red-spotted newts, Notophthalmus viridescens.

    PubMed

    Reedy, Aaron M; Edwards, Alex; Pendlebury, Chloe; Murdaugh, Laura; Avery, Ryan; Seidenberg, Jake; Aspbury, Andrea S; Gabor, Caitlin R

    2014-11-01

    Hormones play key, functional roles in mediating the tradeoff between survival and reproduction. Glucocorticoid hormones can inhibit reproduction and improve chances of survival during periods of stress. However, glucocorticoid hormones are, at times, also associated with successfully engaging in energetically costly courtship and mating behaviors. Corticosterone (CORT), a primary glucocorticoid hormone in amphibians, reptiles and birds, may be important in activating or sustaining energetically costly mating behaviors. We used a non-invasive, water-borne hormone assay to measure CORT release rates of male and female red-spotted newts (Notophthalmus viridescens) collected when either engaged in amplexus or when not engaged in amplexus. Because amplexus is energetically costly for males, we predicted that males would have higher CORT release rates than females. We also predicted that females in amplexus would have elevated CORT release rates because the restraint of amplexus prevents foraging and breathing and may be costly. Here we show that an acute increase in CORT is associated with amplexus behavior in both male and female red-spotted newts. Additionally we demonstrate that males have higher overall CORT release rates both in and out of amplexus than do females. Our results support the hypothesis that glucocorticoid hormones are associated with energetically costly courtship and mating behaviors for both sexes.

  18. Widespread infection of the Eastern red-spotted newt (Notophthalmus viridescens) by a new species of Amphibiocystidium, a genus of fungus-like mesomycetozoan parasites not previously reported in North America.

    PubMed

    Raffel, T R; Bommarito, T; Barry, D S; Witiak, S M; Shackelton, L A

    2008-02-01

    Given the worldwide decline of amphibian populations due to emerging infectious diseases, it is imperative that we identify and address the causative agents. Many of the pathogens recently implicated in amphibian mortality and morbidity have been fungal or members of a poorly understood group of fungus-like protists, the mesomycetozoans. One mesomycetozoan, Amphibiocystidium ranae, is known to infect several European amphibian species and was associated with a recent decline of frogs in Italy. Here we present the first report of an Amphibiocystidium sp. in a North American amphibian, the Eastern red-spotted newt (Notophthalmus viridescens), and characterize it as the new species A. viridescens in the order Dermocystida based on morphological, geographical and phylogenetic evidence. We also describe the widespread and seasonal distribution of this parasite in red-spotted newt populations and provide evidence of mortality due to infection.

  19. Tail regeneration and ependymal outgrowth in the adult newt, Notophthalmus viridescens, are adversely affected by experimentally produced ischemia.

    PubMed

    Tassava, Roy A; Huang, Yan

    2005-12-01

    Spinal axons of the adult newt will regenerate when the spinal cord is severed or when the tail is amputated. Ischemia and associated hypoxia have been correlated with poor central nervous system regeneration in mammals. To test the effects of ischemia on newt spinal cord regeneration, the spinal cord and major blood vessels of the newt tail were severed 2 cm caudal to the cloaca as a primary injury. This primary injury severely reduced circulation in the caudal direction for 7 days; by day 8, circulation was largely restored. After various periods of time after primary injury, tails were amputated 1 cm caudal to the primary injury (in the area of ischemia) and tested for regeneration. If the tail was amputated within 5 days of the primary injury, regeneration did not occur. If amputation was 7 days or longer after the primary injury, a regenerative response occurred. Histology showed that in the non-regenerating tails the spinal cord and associated ependyma, known to be important to tail regeneration, had degenerated in the rostral direction. Such degeneration was prevented when tails were first amputated and allowed to form blastemas before the primary injury. The data indicate that the first 5-7 days of blastema formation are particularly sensitive to compromised blood flow (ischemia/hypoxia). It follows that mechanisms must be present in the adult newt to reduce ischemia to a minimum and thus allow ependymal outgrowth and tail regeneration.

  20. Structure and stability of an acidic fibroblast growth factor from Notophthalmus viridescens.

    PubMed

    Arunkumar, Alphonse Ignatius; Srisailam, Sampath; Kumar, Thallampuranam Krishnaswamy Suresh; Kathir, Karuppanan Muthusamy; Chi, Ya-Hui; Wang, Han-Min; Chang, Gu-Gang; Chiu, Ing- Ming; Yu, Chin

    2002-11-29

    The three-dimensional solution structure of an acidic fibroblast growth factor (nFGF-1) from the newt (Notophthalmus viridescens) is determined using multidimensional NMR techniques. Complete assignment of all the atoms ((1)H, (15)N, and (13)C) has been achieved using a variety of triple resonance experiments. 50 structures were calculated using hybrid distance geometry-dynamical simulated annealing technique with a total of 1359 constraints. The atomic root mean square distribution for the backbone atoms in the structured region is 0.60 A. The secondary structural elements include 12 beta-strands arranged antiparallely into a beta-barrel structure. The protein (nFGF-1) exists in a monomeric state upon binding to the ligand, sucrose octa sulfate (SOS), in a stoichiometric ratio of 1:1. The SOS binding site consists of a dense cluster of positively charged residues located at the C-terminal end of the molecule. The conformational stabilities of nFGF-1 and its structural and functional homologue from the human source (hFGF-1) are drastically different. The differential stabilities of nFGF-1 and hFGF-1 are attributed to the differences in the number of hydrogen bonds and the presence of solvent inaccessible cavities in the two proteins. PMID:12205097

  1. Bimodal locomotion elicited by electrical stimulation of the midbrain in the salamander Notophthalmus viridescens.

    PubMed

    Cabelguen, Jean-Marie; Bourcier-Lucas, Céline; Dubuc, Réjean

    2003-03-15

    The present experiments were designed to identify the mesencephalic locomotor region (MLR) in the salamander. An in vitro semi-intact preparation from a decerebrate adult salamander (Notophthalmus viridescens) was developed in which the locomotor activities were monitored from electromyographic and video recordings. The results show that the two locomotor modes exhibited by salamanders (i.e., stepping and swimming) were evoked by electrical microstimulation (5-15 Hz; 0.1-10 microA; 2 msec pulses) of a circumscribed region in the caudal mesencephalon. At threshold current strength (0.5-3.5 microA at 15 Hz), rhythmic limb movements and intersegmental coordination, such as during stepping, were induced. As the stimulation strength was subsequently increased, the frequency of stepping became more rapid, and, at 2.0-5.5 microA, the limbs were held back against the body wall and swimming movements of the trunk were induced. An additional increase of the stimulation strength induced an increase of the frequency and amplitude of the swimming movements. Anatomical studies conducted in parallel revealed the presence of choline acetyltransferase immunoreactive cells in the functionally identified MLR region. Together, the present results indicate that the MLR is present in salamanders and that its level of activation determines the mode of locomotion. Walking is induced at low activation levels, and swimming, which constitutes a faster mode of locomotion, requires stronger stimulation of the MLR. Furthermore, as in other vertebrates, the MLR contains cholinergic cells.

  2. Modifications of the genital kidney proximal and distal tubules for sperm transport in Notophthalmus viridescens (Amphibia, Urodela, Salamandridae).

    PubMed

    Nicholson, Abbigail E; Siegel, Dustin S

    2014-08-01

    Male salamanders use nephrons from the genital kidney to transport sperm from the testicular lobules to the Wolffian duct. The microstructure of the epithelia of the genital kidney proximal tubule and distal tubule was studied over 1 year in a population of Notophthalmus viridescens from Crawford and Pike counties in central Missouri. Through ultrastructural analysis, we were able to support the hypothesis that the genital kidney nephrons are modified to aid in the transportation of sperm. A lack of folding of the basal plasma membrane, in both the genital kidney proximal and distal tubules when compared to the pelvic kidney proximal and distal tubules, reduces the surface area and thus likely decreases the efficiency of reabsorption in these nephron regions of the genital kidney. Ciliated epithelial cells are also present along the entire length of the genital kidney proximal tubule, but are lacking in the epithelium of the pelvic kidney proximal tubule. The exact function of these cilia remains unknown, but they may aid in mixing of seminal fluids or the transportation of immature sperm through the genital kidney nephrons. Ultrastructural analysis of proximal and distal tubules of the genital kidney revealed no seasonal variation in cellular activity and no mass production of seminal fluids throughout the reproductive cycle. Thus, we failed to support the hypothesis that the cellular activity of the epithelia lining the genital kidney nephrons is correlated to specific events in the reproductive cycle. The cytoplasmic contents and overall structure of the genital and pelvic kidney epithelial cells were similar to recent observations in Ambystoma maculatum, with the absence of abundant dense bodies apically in the epithelial cells lining the genital kidney distal tubule.

  3. Modifications of the genital kidney proximal and distal tubules for sperm transport in Notophthalmus viridescens (Amphibia, Urodela, Salamandridae).

    PubMed

    Nicholson, Abbigail E; Siegel, Dustin S

    2014-08-01

    Male salamanders use nephrons from the genital kidney to transport sperm from the testicular lobules to the Wolffian duct. The microstructure of the epithelia of the genital kidney proximal tubule and distal tubule was studied over 1 year in a population of Notophthalmus viridescens from Crawford and Pike counties in central Missouri. Through ultrastructural analysis, we were able to support the hypothesis that the genital kidney nephrons are modified to aid in the transportation of sperm. A lack of folding of the basal plasma membrane, in both the genital kidney proximal and distal tubules when compared to the pelvic kidney proximal and distal tubules, reduces the surface area and thus likely decreases the efficiency of reabsorption in these nephron regions of the genital kidney. Ciliated epithelial cells are also present along the entire length of the genital kidney proximal tubule, but are lacking in the epithelium of the pelvic kidney proximal tubule. The exact function of these cilia remains unknown, but they may aid in mixing of seminal fluids or the transportation of immature sperm through the genital kidney nephrons. Ultrastructural analysis of proximal and distal tubules of the genital kidney revealed no seasonal variation in cellular activity and no mass production of seminal fluids throughout the reproductive cycle. Thus, we failed to support the hypothesis that the cellular activity of the epithelia lining the genital kidney nephrons is correlated to specific events in the reproductive cycle. The cytoplasmic contents and overall structure of the genital and pelvic kidney epithelial cells were similar to recent observations in Ambystoma maculatum, with the absence of abundant dense bodies apically in the epithelial cells lining the genital kidney distal tubule. PMID:24643856

  4. Habitat Suitability Index Models: Red-spotted newt

    USGS Publications Warehouse

    Sousa, Patrick J.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the red-spotted newt (Notophthalmus viridescens viridescens). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  5. Habitat Suitability Index Models: Red-Spotted Newt

    USGS Publications Warehouse

    Sousa, Patrick J.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the red-spotted newt (Notophthalmus viridescens viridescens). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  6. Disease dynamics of red-spotted newts and their anuran prey in a montane pond community.

    PubMed

    Rothermel, Betsie B; Miller, Debra L; Travis, Emilie R; Gonynor McGuire, Jessica L; Jensen, John B; Yabsley, Michael J

    2016-02-25

    Long-term monitoring of amphibians is needed to clarify population-level effects of ranaviruses (Rv) and the fungal pathogen Batrachochytrium dendrobatidis (Bd). We investigated disease dynamics of co-occurring amphibian species and potential demographic consequences of Rv and Bd infections at a montane site in the Southern Appalachians, Georgia, USA. Our 3-yr study was unique in combining disease surveillance with intensive population monitoring at a site where both pathogens are present. We detected sub-clinical Bd infections in larval and adult red-spotted newts Notophthalmus viridescens viridescens, but found no effect of Bd on body condition of adult newts. Bd infections also occurred in larvae of 5 anuran species that bred in our fishless study pond, and we detected co-infections with Bd and Rv in adult newts and larval green frogs Lithobates clamitans. However, all mortality and clinical signs in adult newts and larval anurans were most consistent with ranaviral disease, including a die-off of larval wood frogs Lithobates sylvaticus in small fish ponds located near our main study pond. During 2 yr of drift fence monitoring, we documented high juvenile production in newts, green frogs and American bullfrogs L. catesbeianus, but saw no evidence of juvenile recruitment in wood frogs. Larvae of this susceptible species may have suffered high mortality in the presence of both Rv and predators. Our findings were generally consistent with results of Rv-exposure experiments and support the purported role of red-spotted newts, green frogs, and American bullfrogs as common reservoirs for Bd and/or Rv in permanent and semi-permanent wetlands.

  7. Disease dynamics of red-spotted newts and their anuran prey in a montane pond community.

    PubMed

    Rothermel, Betsie B; Miller, Debra L; Travis, Emilie R; Gonynor McGuire, Jessica L; Jensen, John B; Yabsley, Michael J

    2016-02-25

    Long-term monitoring of amphibians is needed to clarify population-level effects of ranaviruses (Rv) and the fungal pathogen Batrachochytrium dendrobatidis (Bd). We investigated disease dynamics of co-occurring amphibian species and potential demographic consequences of Rv and Bd infections at a montane site in the Southern Appalachians, Georgia, USA. Our 3-yr study was unique in combining disease surveillance with intensive population monitoring at a site where both pathogens are present. We detected sub-clinical Bd infections in larval and adult red-spotted newts Notophthalmus viridescens viridescens, but found no effect of Bd on body condition of adult newts. Bd infections also occurred in larvae of 5 anuran species that bred in our fishless study pond, and we detected co-infections with Bd and Rv in adult newts and larval green frogs Lithobates clamitans. However, all mortality and clinical signs in adult newts and larval anurans were most consistent with ranaviral disease, including a die-off of larval wood frogs Lithobates sylvaticus in small fish ponds located near our main study pond. During 2 yr of drift fence monitoring, we documented high juvenile production in newts, green frogs and American bullfrogs L. catesbeianus, but saw no evidence of juvenile recruitment in wood frogs. Larvae of this susceptible species may have suffered high mortality in the presence of both Rv and predators. Our findings were generally consistent with results of Rv-exposure experiments and support the purported role of red-spotted newts, green frogs, and American bullfrogs as common reservoirs for Bd and/or Rv in permanent and semi-permanent wetlands. PMID:26912042

  8. Expression of complement 3 and complement 5 in newt limb and lens regeneration.

    PubMed

    Kimura, Yuko; Madhavan, Mayur; Call, Mindy K; Santiago, William; Tsonis, Panagiotis A; Lambris, John D; Del Rio-Tsonis, Katia

    2003-03-01

    Some urodele amphibians possess the capacity to regenerate their body parts, including the limbs and the lens of the eye. The molecular pathway(s) involved in urodele regeneration are largely unknown. We have previously suggested that complement may participate in limb regeneration in axolotls. To further define its role in the regenerative process, we have examined the pattern of distribution and spatiotemporal expression of two key components, C3 and C5, during limb and lens regeneration in the newt Notophthalmus viridescens. First, we have cloned newt cDNAs encoding C3 and C5 and have generated Abs specifically recognizing these molecules. Using these newt-specific probes, we have found by in situ hybridization and immunohistochemical analysis that these molecules are expressed during both limb and lens regeneration, but not in the normal limb and lens. The C3 and C5 proteins were expressed in a complementary fashion during limb regeneration, with C3 being expressed mainly in the blastema and C5 exclusively in the wound epithelium. Similarly, during the process of lens regeneration, C3 was detected in the iris and cornea, while C5 was present in the regenerating lens vesicle as well as the cornea. The distinct expression profile of complement proteins in regenerative tissues of the urodele lens and limb supports a nonimmunologic function of complement in tissue regeneration and constitutes the first systematic effort to dissect its involvement in regenerative processes of lower vertebrate species. PMID:12594255

  9. Is there more than one way to skin a newt? Convergent toxin resistance in snakes is not due to a common genetic mechanism.

    PubMed

    Feldman, C R; Durso, A M; Hanifin, C T; Pfrender, M E; Ducey, P K; Stokes, A N; Barnett, K E; Brodie, E D; Brodie, E D

    2016-01-01

    Convergent evolution of tetrodotoxin (TTX) resistance, at both the phenotypic and genetic levels, characterizes coevolutionary arms races between amphibians and their snake predators around the world, and reveals remarkable predictability in the process of adaptation. Here we examine the repeatability of the evolution of TTX resistance in an undescribed predator-prey relationship between TTX-bearing Eastern Newts (Notophthalmus viridescens) and Eastern Hog-nosed Snakes (Heterodon platirhinos). We found that that local newts contain levels of TTX dangerous enough to dissuade most predators, and that Eastern Hog-nosed Snakes within newt range are highly resistant to TTX. In fact, these populations of Eastern Hog-nosed Snakes are so resistant to TTX that the potential for current reciprocal selection might be limited. Unlike all other cases of TTX resistance in vertebrates, H. platirhinos lacks the adaptive amino acid substitutions in the skeletal muscle sodium channel that reduce TTX binding, suggesting that physiological resistance in Eastern Hog-nosed Snakes is conferred by an alternate genetic mechanism. Thus, phenotypic convergence in this case is not due to parallel molecular evolution, indicating that there may be more than one way for this adaptation to arise, even among closely related species. PMID:26374236

  10. Is there more than one way to skin a newt? Convergent toxin resistance in snakes is not due to a common genetic mechanism.

    PubMed

    Feldman, C R; Durso, A M; Hanifin, C T; Pfrender, M E; Ducey, P K; Stokes, A N; Barnett, K E; Brodie, E D; Brodie, E D

    2016-01-01

    Convergent evolution of tetrodotoxin (TTX) resistance, at both the phenotypic and genetic levels, characterizes coevolutionary arms races between amphibians and their snake predators around the world, and reveals remarkable predictability in the process of adaptation. Here we examine the repeatability of the evolution of TTX resistance in an undescribed predator-prey relationship between TTX-bearing Eastern Newts (Notophthalmus viridescens) and Eastern Hog-nosed Snakes (Heterodon platirhinos). We found that that local newts contain levels of TTX dangerous enough to dissuade most predators, and that Eastern Hog-nosed Snakes within newt range are highly resistant to TTX. In fact, these populations of Eastern Hog-nosed Snakes are so resistant to TTX that the potential for current reciprocal selection might be limited. Unlike all other cases of TTX resistance in vertebrates, H. platirhinos lacks the adaptive amino acid substitutions in the skeletal muscle sodium channel that reduce TTX binding, suggesting that physiological resistance in Eastern Hog-nosed Snakes is conferred by an alternate genetic mechanism. Thus, phenotypic convergence in this case is not due to parallel molecular evolution, indicating that there may be more than one way for this adaptation to arise, even among closely related species.

  11. Transcriptome Analysis of Newt Lens Regeneration Reveals Distinct Gradients in Gene Expression Patterns

    PubMed Central

    Maki, Nobuyasu; Ivester, Clifford J.; Braun, Thomas; Tsonis, Panagiotis A.

    2013-01-01

    Regeneration of the lens in newts is quite a unique process. The lens is removed in its entirety and regeneration ensues from the pigment epithelial cells of the dorsal iris via transdifferentiation. The same type of cells from the ventral iris are not capable of regenerating a lens. It is, thus, expected that differences between dorsal and ventral iris during the process of regeneration might provide important clues pertaining to the mechanism of regeneration. In this paper, we employed next generation RNA-seq to determine gene expression patterns during lens regeneration in Notophthalmus viridescens. The expression of more than 38,000 transcripts was compared between dorsal and ventral iris. Although very few genes were found to be dorsal- or ventral-specific, certain groups of genes were up-regulated specifically in the dorsal iris. These genes are involved in cell cycle, gene regulation, cytoskeleton and immune response. In addition, the expression of six highly regulated genes, TBX5, FGF10, UNC5B, VAX2, NR2F5, and NTN1, was verified using qRT-PCR. These graded gene expression patterns provide insight into the mechanism of lens regeneration, the markers that are specific to dorsal or ventral iris, and layout a map for future studies in the field. PMID:23613853

  12. Cellular proliferation in the skin of X-rayed newt limbs (with a note on x-ray-induced limb regression)

    SciTech Connect

    Wertz, R.L.

    1982-07-01

    Left hind limbs, including the pelvis, of adult newts (Notophthalmus viridescens) were locally irradiated with a dose of x-rays that inhibited regeneration (2,000 R). This x-ray dose and other doses (700-2,000 R) capable of inhibiting limb regeneration also cause limb regression prior to amputation. Before limb regression occurred, there was a latent period of 3 to 6 weeks. Limb regression was characterized by necrotic wasting and resorption of distal elements. The degree of loss was variable and dependent upon dosage. After this further degenerative changes were not noted. Proliferation of epidermal cells was examined 4 days after irradiation prior to limb regression or after x-ray-induced degeneration of the limbs had ended. Proliferative activity in x-rayed limbs was also compared at various stages of contralateral control limb regeneration. Limbs examined after x-ray-induced limb regression had ended showed levels of (/sup 3/H)-thymidine incorporation into DNA comparable to normal epidermis. In contrast, limbs examined 4 days after irradiation had lower levels of DNA synthesis (P much less than 0.01). Amputation of limbs in both groups caused an increase in DNA synthesis (P much less than 0.01). Histological examination showed that cellular proliferation was associated primarily with the epidermis. These results indicate that epidermal cell proliferation was not resistant to x-rays. However, levels of normal cell division were observed after amputation of after cessation of x-ray-induced limb regression.

  13. Disentangling the Trichoderma viridescens complex.

    PubMed

    Jaklitsch, W M; Samuels, G J; Ismaiel, A; Voglmayr, H

    2013-12-01

    Trichoderma viridescens is recognised as a species complex. Multigene analyses based on the translation elongation factor 1-alpha encoding gene (tef1), a part of the rpb2 gene, encoding the second largest RNA polymerase subunit and the larger subunit of ATP citrate lyase (acl1) reveals 13 phylogenetic species with little or no phenotypic differentiation. This is the first use of acl1 in Trichoderma phylogenetics. The typification of T. viridescens s.str. is clarified and Hypocrea viridescens is replaced by the new name T. paraviridescens. Besides these two species, eleven are phylogenetically recognised and T. olivascens, T. viridarium, T. virilente, T. trixiae, T. viridialbum, T. appalachiense, T. neosinense, T. composticola, T. nothescens and T. sempervirentis are formally described and illustrated. Several species produce yellow diffusing pigment on cornmeal dextrose agar, particularly after storage at 15 °C, while T. olivascens is characterised by the formation of an olivaceous pigment. The results are compared with earlier publications on this group of species.

  14. Orientation and migration distances of a pond-breeding salamander (Notophthalmus perstriatus, Salamandridae)

    USGS Publications Warehouse

    Johnson, S. A.

    2003-01-01

    Habitat loss and modification have played a significant role in the decline of amphibian populations and species. Loss of wetlands, which are used as breeding sites for many amphibians, has contributed to the decline. The protection of small, isolated wetlands and core areas of associated uplands is one way in which population declines in certain species can be slowed or prevented. Nevertheless, migration distances of individuals of most amphibian species from their breeding sites are unknown. Using drift fences and pitfall traps, I studied migration distance and orientation of striped newts (Notophthalmus perstriatus) at a breeding pond in northern Florida, USA. Newts entered (immigration) and exited (emigration) the pond basin in a nonrandom fashion but no obvious effects of upland habitat were apparent. Patterns of emigration and immigration differed significantly between sexes, life-history stages, and migration events. Individuals tended to exit and enter the pond basin within the same quadrant, sometimes leaving and returning at the same point. Newts moved hundreds of meters into the sandhill uplands surrounding the pond. I found an inverse relationship between the proportion of newts migrating and distance from the pond. Nonetheless, I estimated that at least 16% of individuals breeding at the pond migrated in excess of 500 m from the pond. Thus, a core of protected upland with a radius of approximately 800 m from the pond would be needed to preserve the area used by the vast majority of individuals that breed at the pond. These data underscore the need to study upland habitat requirements for amphibians; findings for one taxon (e.g. ambystomatids) may not be applicable to others (e.g., salamandrids). Without such data, designating terrestrial core habitat to conserve aquatic-breeding amphibians will be difficult or impossible. However, without better protection of small, isolated wetlands, arguments to preserve surrounding uplands are irrelevant.

  15. Classroom Animal: Newts.

    ERIC Educational Resources Information Center

    Kramer, David C.

    1987-01-01

    Describes the habitats and life cycles of newts. Provides tips on collecting and caring for newts, along with suggestions for observational lessons related to the collection, study, and release of these organisms. (TW)

  16. Chromosomal variation in the northwestern American newts of the genus Taricha (Caudata: Salamandridae).

    PubMed

    Tan, A M

    1994-07-01

    Chromosomal variation was analysed in 22 populations of newts of the salmandrid genus Taricha of western North America, and compared with that of the eastern North American newts of the genus Notophthalmus. The karyotypes of the species Taricha and Notophthalmus were very similar. However, there was considerable variation in the distribution patterns of heterochromatins (revealed by C-banding) and in the sites of the nucleolar organizing region (NOR) (revealed by fluorochrome chromomycin A3 banding) within and between species of these two genera. Chromosomal variation patterns were interpreted in relation to a phylogenetic hypothesis derived from data on mitochondrial DNA sequences and allozyme variation. This study suggests that the pattern distributions of heterochromatins in chromosomes of Taricha are more derived than those of its sister taxon Notophthalmus. Furthermore, the chromosomal NOR types found in the southernmost and northernmost populations of T. granulosa, in the northernmost populations of T. t. sierrae, and in the southern populations of T. t. torosa are recently derived. The implications of this chromosomal variation for phylogeny and biogeography are discussed.

  17. Life history of the striped newt at a north-central Florida breeding pond

    USGS Publications Warehouse

    Johnson, S.A.

    2002-01-01

    I studied the life history of Striped Newts (Notophthalmus perstriatus) at a breeding pond in north-central Florida. Newts were captured in pitfall traps at a drift-fence as they migrated into and out of the pond basin. During the 2-year study, I recorded 10,290 captures (8,127 individuals) of newts at the drift-fence. Newts were active during each month of the study, but there were four peak activity periods, each of which included immigration and emigration events. Immigration events were almost exclusively comprised of adults, whereas emigration events were comprised of adults and recently transformed larvae. I documented 5,296 recently transformed, immature larvae (efts) and 435 recently transformed mature larvae (paedomorphs) during four distinct periods of emigration. Efts matured in the uplands before returning to the pond to breed. In the uplands, male efts (n = 16) grew 0.0183 mm/day on average, whereas average female (n = 24) growth was 0.0167 mm/day. Immigrating adults of both sexes were significantly smaller than emigrating adults. Emigrating efts were smallest, followed by emigrating paedomorphs, immigrating adults, then emigrating adults. The overall adult sex ratio was 1:1.25 (m:f). Sex ratio of emigrating paedomorphs was highly skewed towards females, with one male for every 4.43 females. Newts tended to move during wetter periods, and captures were significantly correlated with rainfall, but rainfall was a poor predictor of the magnitude of newt movements.

  18. Mutagenesis in Newts: Protocol for Iberian Ribbed Newts.

    PubMed

    Hayashi, Toshinori; Takeuchi, Takashi

    2016-01-01

    Newts have the remarkable capability of organ/tissue regeneration, and have been used as a unique experimental model for regenerative biology. The Iberian ribbed newt (Pleurodeles waltl) is suitable as a model animal. We have established methods for artificial insemination and efficient transgenesis using P. waltl newts. In addition to the transgenic technique, development of TALENs enables targeting mutagenesis in the newts. We have reported that TALENs efficiently disrupted targeted genes in newt embryos. In this chapter, we introduce a protocol for TALEN-mediated gene targeting in Iberian ribbed newts. PMID:26443218

  19. Mutagenesis in Newts: Protocol for Iberian Ribbed Newts.

    PubMed

    Hayashi, Toshinori; Takeuchi, Takashi

    2016-01-01

    Newts have the remarkable capability of organ/tissue regeneration, and have been used as a unique experimental model for regenerative biology. The Iberian ribbed newt (Pleurodeles waltl) is suitable as a model animal. We have established methods for artificial insemination and efficient transgenesis using P. waltl newts. In addition to the transgenic technique, development of TALENs enables targeting mutagenesis in the newts. We have reported that TALENs efficiently disrupted targeted genes in newt embryos. In this chapter, we introduce a protocol for TALEN-mediated gene targeting in Iberian ribbed newts.

  20. AstroNewt: early development of newt in space.

    PubMed

    Mogami, Y; Imamizo, M; Yamashita, M; Izumi-Kurotani, A; Wiederhold, M L; Koike, H; Asashima, M

    1996-01-01

    AstroNewt experiment explores the effects of earth gravity on the early development of Japanese red-bellied newt, Cynops pyrrhogaster. Since female newts keep spermatophore in cloaca, fertilized eggs could be obtained without mating. Fertilization of newt's egg occurs just prior to spawning, so that gonadotrophic cues applied to females in orbit leads to laying eggs fertilized just in space. A property of newt being kept in hibernation at low temperature may be of great help for the space experiment carried out with much limited resources. A general outline of the AstroNewt project is shown here in addition to some technical advances for the development of the project. Experimental schemes of two space experiments (IML-2 in summer 1994 and unmanned SFU at the beginning of 1995) are also shown.

  1. A Bayesian approach on molecules and behavior: reconsidering phylogenetic and evolutionary patterns of the Salamandridae with emphasis on Triturus newts.

    PubMed

    Steinfartz, Sebastian; Vicario, Saverio; Arntzen, J W; Caccone, Adalgisa

    2007-03-15

    The monophyly of European newts of the genus Triturus within the family Salamandridae has for decades rested on presumably homologous behavioral and morphological characters. Molecular data challenge this hypothesis, but the phylogenetic position of Triturus within the Salamandridae has not yet been convincingly resolved. We addressed this issue and the temporal divergence of Triturus within the Salamandridae with novel Bayesian approaches applied to DNA sequence data from three mitochondrial genes (12S, 16S and cytb). We included 38 salamandrid species comprising all 13 recognized species of Triturus and 16 out of 17 salamandrid genera. A clade comprising all the "Newts" can be separated from the "True Salamanders" and Salamandrina clades. Within the "Newts" well-supported clades are: Tylototriton-Pleurodeles, the "New World Newts" (Notophthalmus-Taricha), and the "Modern Eurasian Newts" (Cynops, Pachytriton, Paramesotriton=together the "Modern Asian Newts", Calotriton, Euproctus, Neurergus and Triturus species). We found that Triturus is a non-monophyletic species assemblage, which includes four groups that are themselves monophyletic: (i) the "Large-Bodied Triturus" (six species), (ii) the "Small-Bodied Triturus" (five species), (iii) T. alpestris and (iv) T. vittatus. We estimated that the last common ancestor of Triturus existed around 64 million years ago (mya) while the root of the Salamandridae dates back to 95 mya. This was estimated using a fossil-based molecular dating approach and an explicit framework to select calibration points that least underestimated their corresponding nodes. Using the molecular phylogeny we mapped the evolution of life history and courtship traits in Triturus and found that several Triturus-specific courtship traits evolved independently.

  2. Newts: sun-compass orientation.

    PubMed

    Landreth, H F; Ferguson, D E

    1967-12-15

    Rough-skinned newts, captured from breeding ponds, oriented on courses that would have intersected the familiar shorelines at right angles, when released in a circular arena on land under the sun or moon. Pondward migrants oriented similarly. Reorientation failed under complete cloud cover and after 7 days of darkness in an environmental chamber, but persisted in newts whose eyes were excised and in those displaced more than 27 kilometers in darkness. Both normal and blind animals compensated for displacement in sunshine. Preliminary evidence suggests that alternative light receptors in blinded animals may be associated with the optic tectum. No evidence of olfactory guidance was observed. PMID:6058684

  3. Astronewt: early development of newt in space

    NASA Astrophysics Data System (ADS)

    Mogami, Y.; Imamizo, M.; Yamashita, M.; Izumi-Kurotani, A.; Wiederhold, M. L.; Koike, H.; Asashima, M.

    AstroNewt experiment explores the effects of earth gravity on the early development of Japanese red-bellied newt, Cynops pyrrhogaster. Since female newts keep spermatophore in cloaca, fertilized eggs could be obtained without mating. Fertilization of newt's egg occurs just prior to spawning, so that gonadotrophic cues applied to females in orbit leads to laying eggs fertilized just in space. A property of newt being kept in hibernation at low temperature may be of great help for the space experiment carried out with much limited resources. A general outline of the AstroNewt project is shown here in addition to some technical advances for the development of the project. Experimental schemes of two space experiments (IML-2 in summer 1994 and unmanned SFU at the beginning of 1995) are also shown.

  4. A transcriptome for the study of early processes of retinal regeneration in the adult newt, Cynops pyrrhogaster.

    PubMed

    Nakamura, Kenta; Islam, Md Rafiqul; Takayanagi, Miyako; Yasumuro, Hirofumi; Inami, Wataru; Kunahong, Ailidana; Casco-Robles, Roman M; Toyama, Fubito; Chiba, Chikafumi

    2014-01-01

    Retinal regeneration in the adult newt is a useful system to uncover essential mechanisms underlying the regeneration of body parts of this animal as well as to find clues to treat retinal disorders such as proliferative vitreoretinopathy. Here, to facilitate the study of early processes of retinal regeneration, we provide a de novo assembly transcriptome and inferred proteome of the Japanese fire bellied newt (Cynops pyrrhogaster), which was obtained from eyeball samples of day 0-14 after surgical removal of the lens and neural retina. This transcriptome (237,120 in silico transcripts) contains most information of cDNAs/ESTs which has been reported in newts (C. pyrrhogaster, Pleurodeles waltl and Notophthalmus viridescence) thus far. On the other hand, de novo assembly transcriptomes reported lately for N. viridescence only covered 16-31% of this transcriptome, suggesting that most constituents of this transcriptome are specific to the regenerating eye tissues of C. pyrrhogaster. A total of 87,102 in silico transcripts of this transcriptome were functionally annotated. Coding sequence prediction in combination with functional annotation revealed that 76,968 in silico transcripts encode protein/peptides recorded in public databases so far, whereas 17,316 might be unique. qPCR and Sanger sequencing demonstrated that this transcriptome contains much information pertaining to genes that are regulated in association with cell reprogramming, cell-cycle re-entry/proliferation, and tissue patterning in an early phase of retinal regeneration. This data also provides important insight for further investigations addressing cellular mechanisms and molecular networks underlying retinal regeneration as well as differences between retinal regeneration and disorders. This transcriptome can be applied to ensuing comprehensive gene screening steps, providing candidate genes, regardless of whether annotated or unique, to uncover essential mechanisms underlying early processes of

  5. Acanthagrion viridescens (Odonata: Coenagrionidae): description of the final larval stadium and biological notes.

    PubMed

    Gutiérrez, Yeisson; Freitas, Hemerson L; Oliveira, Eugênio E

    2015-01-01

    The development of the nymphal stages of Acanthagrion viridescens Leonard was examined under laboratory conditions. Based on specimens collected in Minas Gerais state (Brazilian Southeastern Region), we described and illustrated the last-instar nymph and illustrated the egg and other nymphal stages. The nymphs of A. viridescens went through 11 instars, each of them with an average duration of approximately 13 days. The combinations of the following characteristics distinguish the last-instar nymph of A. viridescens from congeners: prementum with 2+1 setae in each side; labial palp with six apical denticles; mandibular formula L 1+2 3 4 5 y a, R 1+2 3 4 5 y- a b; presence of trifid spine in the ventral distal region of the tibia and in the tarsi; format of the male and female gonapophyses; and the distinctive pattern of the tracheae in the caudal gills. This also represents the first record of this species from southeastern Brazil. PMID:26701470

  6. Expressing exogenous genes in newts by transgenesis.

    PubMed

    Casco-Robles, Martin Miguel; Yamada, Shouta; Miura, Tomoya; Nakamura, Kenta; Haynes, Tracy; Maki, Nobuyasu; Del Rio-Tsonis, Katia; Tsonis, Panagiotis A; Chiba, Chikafumi

    2011-05-01

    The great regenerative abilities of newts provide the impetus for studies at the molecular level. However, efficient methods for gene regulation have historically been quite limited. Here we describe a protocol for transgenically expressing exogenous genes in the newt Cynops pyrrhogaster. This method is simple: a reaction mixture of I-SceI meganuclease and a plasmid DNA carrying a transgene cassette flanked by the enzyme recognition sites is directly injected into fertilized eggs. The protocol achieves a high efficiency of transgenesis, comparable to protocols used in other animal systems, and it provides a practical number of transgenic newts (∼20% of injected embryos) that survive beyond metamorphosis and that can be applied to regenerative studies. The entire protocol for obtaining transgenic adult newts takes 4-5 months.

  7. [Identification of the Gene Encoding Nucleostemin in the Eye Tissues of Pleurodeles waltl].

    PubMed

    Markitantova, Y V; Avdonin, P P; Grigoryan, E N

    2015-01-01

    Nucleotide sequences were identified in the eye tissues (lens, retina, and retinal pigment epithelium) of the adult newt Pleurodeles waltl by the polymerase chain reaction with primers for the Ns gene. Sequencing showed that these nucleotide sequences belong to the Ns gene of the newt P. walt, which encodes the nucleolar protein nucleostemin. Structural analysis revealed a high homology of Ns nucleotide sequences of P. walt! with those of newts. Cynops pyrrhogaster and Notophthalmus viridescens. The expression of the Ns gene of P. walt, identified in the specialized eye cells of adult newts of the studied species, indicates that these differentiated cells retain some of the molecular characteristics inherent to the undifferentiated cells. PMID:26638232

  8. Preliminary amphibian health survey in the Delaware Water Gap National Recreation Area.

    PubMed

    Glenney, Gavin W; Julian, James T; Quartz, William M

    2010-06-01

    To detect aquatic animal diseases of national concern, 111 individual amphibians, including wood frogs Rana sylvatica (28), spring peepers Pseudacris crucifer (35), red-spotted newts Notophthalmus viridescens (41), and gray tree frogs Hyla versicolor (7), were sampled at seven different sites in the Delaware Water Gap National Recreation Area (DGNRA), Pennsylvania, from June 14 to July 19, 2007. These samples were screened for Batrachochytrium dendrobatidis and viral pathogens at the U.S. Fish and Wildlife Service's Fish Health Center in Lamar, Pennsylvania. Cell culture revealed cytopathic effect (CPE) in two cell lines (epithelioma papillosum cyprini and fathead minnow) inoculated with liver, kidney, and spleen samples from one sample pool of Notophthalmus viridescens (4 individuals). Polymerase chain reaction was conducted on cell culture supernatant exhibiting CPE. Sequencing revealed the resulting product to be identical to frog virus 3, a ranavirus in the family Iridoviridae. Upon gross examination, two Notophthalmus viridescens were found to exhibit dermal swelling and lethargy. Histological examination of these lesions revealed involvement by an Ichthyophonus sp. In summary, two pathogens of concern were found in amphibians in the DGNRA: a ranavirus with a major capsid protein sequence identical to that of frog virus 3 and a mesomycetozoan, Ichthyophonus sp. Although no epizootic die-offs were observed during this health survey, the results warrant further research into the distribution of these pathogens throughout the DGNRA because they have the potential to cause mass mortalities in amphibians. PMID:20848885

  9. Long-term organ cultures of newt hearts.

    PubMed

    Piatkowski, Tanja; Braun, Thomas

    2015-01-01

    Adult newts regenerate their hearts after injury by initiating proliferation of cardiac muscle and non-muscle cells. Mechanistic studies in vivo to analyze heart regeneration are challenging due to the long reproduction cycle of newts and the complexity of the genome. Culture of primary newt cells might offer alternative experimental approaches, but monolayers of newt cardiomyocytes and slice cultures of newt hearts show extensive morphological changes during cultivation. Hence, we developed a protocol to culture intact newt hearts in vitro, avoiding major morphological changes of explanted organs during a 5-week cultivation. The model provides improved accessibility and allows manipulation of cultured organs by small molecules and viral vectors. We found that dedifferentiation and S-phase entry of cardiomyocytes, which are hallmarks of cardiac regeneration in vivo, can be recapitulated in cultured hearts in vitro. We reason that long-term organ cultures of newts are a versatile tool for mechanistic studies on organ regeneration.

  10. Husbandry of Spanish ribbed newts (Pleurodeles waltl).

    PubMed

    Joven, Alberto; Kirkham, Matthew; Simon, András

    2015-01-01

    Research on urodele amphibians, such as newts, is constantly contributing to our understanding of fundamental biological processes. In the present chapter, we present detailed husbandry protocols for the Spanish ribbed newt (Pleurodeles waltl ). We describe the main phases of their life cycle, with emphasis on the progressive development of sensory, motor, and integration systems, which lead to the acquisition of specific stereotyped (and conditioned) behaviors. The methods are outlined to manage housing, feeding, handling, captive breeding, health monitoring, and euthanasia in this species under laboratory conditions. With minor changes, these protocols can also be applied to other species of urodele amphibians commonly used in laboratory research.

  11. Molecular genetic system for regenerative studies using newts.

    PubMed

    Hayashi, Toshinori; Yokotani, Naoki; Tane, Shoji; Matsumoto, Akira; Myouga, Ayumi; Okamoto, Mitsumasa; Takeuchi, Takashi

    2013-02-01

    Urodele newts have the remarkable capability of organ regeneration, and have been used as a unique experimental model for more than a century. However, the mechanisms underlying regulation of the regeneration are not well understood, and gene functions in particular remain largely unknown. To elucidate gene function in regeneration, molecular genetic analyses are very powerful. In particular, it is important to establish transgenic or knockout (mutant) lines, and systematically cross these lines to study the functions of the genes. In fact, such systems have been developed for other vertebrate models. However, there is currently no experimental model system using molecular genetics for newt regenerative research due to difficulties with respect to breeding newts in the laboratory. Here, we show that the Iberian ribbed newt (Pleurodeles waltl) has outstanding properties as a laboratory newt. We developed conditions under which we can obtain a sufficient number and quality of eggs throughout the year, and shortened the period required for sexual maturation from 18 months to 6 months. In addition, P. waltl newts are known for their ability, like other newts, to regenerate various tissues. We revealed that their ability to regenerate various organs is equivalent to that of Japanese common newts. We also developed a method for efficient transgenesis. These studies demonstrate that P. waltl newts are a suitable model animal for analysis of regeneration using molecular genetics. Establishment of this experimental model will enable us to perform comparable studies using these newts and other vertebrate models.

  12. Fundamental differences in dedifferentiation and stem cell recruitment during skeletal muscle regeneration in two salamander species.

    PubMed

    Sandoval-Guzmán, Tatiana; Wang, Heng; Khattak, Shahryar; Schuez, Maritta; Roensch, Kathleen; Nacu, Eugeniu; Tazaki, Akira; Joven, Alberto; Tanaka, Elly M; Simon, András

    2014-02-01

    Salamanders regenerate appendages via a progenitor pool called the blastema. The cellular mechanisms underlying regeneration of muscle have been much debated but have remained unclear. Here we applied Cre-loxP genetic fate mapping to skeletal muscle during limb regeneration in two salamander species, Notophthalmus viridescens (newt) and Ambystoma mexicanum (axolotl). Remarkably, we found that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. In the newt, myofiber fragmentation results in proliferating, PAX7(-) mononuclear cells in the blastema that give rise to the skeletal muscle in the new limb. In contrast, myofibers in axolotl do not generate proliferating cells, and do not contribute to newly regenerated muscle; instead, resident PAX7(+) cells provide the regeneration activity. Our results therefore show significant diversity in limb muscle regeneration mechanisms among salamanders and suggest that multiple strategies may be feasible for inducing regeneration in other species, including mammals. PMID:24268695

  13. Fundamental differences in dedifferentiation and stem cell recruitment during skeletal muscle regeneration in two salamander species.

    PubMed

    Sandoval-Guzmán, Tatiana; Wang, Heng; Khattak, Shahryar; Schuez, Maritta; Roensch, Kathleen; Nacu, Eugeniu; Tazaki, Akira; Joven, Alberto; Tanaka, Elly M; Simon, András

    2014-02-01

    Salamanders regenerate appendages via a progenitor pool called the blastema. The cellular mechanisms underlying regeneration of muscle have been much debated but have remained unclear. Here we applied Cre-loxP genetic fate mapping to skeletal muscle during limb regeneration in two salamander species, Notophthalmus viridescens (newt) and Ambystoma mexicanum (axolotl). Remarkably, we found that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. In the newt, myofiber fragmentation results in proliferating, PAX7(-) mononuclear cells in the blastema that give rise to the skeletal muscle in the new limb. In contrast, myofibers in axolotl do not generate proliferating cells, and do not contribute to newly regenerated muscle; instead, resident PAX7(+) cells provide the regeneration activity. Our results therefore show significant diversity in limb muscle regeneration mechanisms among salamanders and suggest that multiple strategies may be feasible for inducing regeneration in other species, including mammals.

  14. Paedogenesis in european newts (Triturus: salamandridae): cranial morphology during ontogeny.

    PubMed

    Djorović, A; Kalezić, M L

    2000-02-01

    A cross-sectional analysis using different ontogenetic stages (larvae, juveniles, paedotypic, and metamorphic adults) of the smooth newt, Triturus vulgaris, and the alpine newt, T.alpestris, revealed a broad spectrum of perennibranchiation influences on cranial ontogeny in European newts, more pronounced than previously thought. These influences included marked variation in ossification levels, pronounced morphometric variability of many cranial elements, and considerable skull shape changes in the transition from larvae to the adult stage. In comparison with metamorphosed individuals, paedotypic newts had a higher level of variability in both individual cranial traits and cranial shape changes. Sexual size difference of the skull traits was mostly negligible, especially in comparison to the influence of paedogenesis. The main changes in cranial shape of the European newts occurred during metamorphosis. Cranial morphological organization in the majority of examined paedotypes corresponds to cranial organization at late larval stages prior to metamorphosis or at the onset of metamorphosis.

  15. Isolation and culture of neurospheres from the adult newt brain.

    PubMed

    Hameed, Liyakath Ali Shahul; Simon, András

    2015-01-01

    Neural stem cells (NSCs) give rise to neurons in the adult brain and are possible targets in regenerative therapies. In vitro cultures of NSCs as neurospheres have been established from cells isolated from diverse species. Newts are exceptional regenerators among vertebrates. These animals are able to efficiently replace neurons following ablation of those by activation and subsequent differentiation of NSCs. Here we describe the method for isolating and culturing of NSCs from the newt brain both during self-renewing and differentiating conditions. Newt NSC culture provides a useful tool for functional studies of NSC fate with the potential of resulting in novel regenerative strategies.

  16. Row erupts over axed chapter from Newt Gingrich book

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2012-02-01

    A chapter written by a respected climate scientist for a book co-edited by Republican presidential candidate Newt Gingrich has been canned because its author asserts that humans are responsible for climate change.

  17. Japanese red-bellied newts in Space--AstroNewt experiment on Space Shuttle IML-2 and Space Flyer Unit.

    PubMed

    Yamashita, M; Izumi-Kurotani, A; Imamizo, M; Koike, H; Okuno, M; Pfeiffer, C J; Komazaki, S; Sasaki, F; Ohira, Y; Kashima, I; Kikuyama, S; Ohnishi, T; Mogami, Y; Asashima, M

    2001-10-01

    Biological effects of gravity was examined in embryonic development of Japanese red bellied newt. Two space newt missions were conducted in 1994 and 1995. The Second International Microgravity Laboratory was flown in 1994 as one of the SpaceLab missions. Space Flyer Unit, a Japanese space platform, was delivered to the earth orbit by the third launch of the H-II rocket and retrieved by Space Shuttle in 1996. Female newts were induced to lay eggs in orbit at these two space missions. Eggs were successfully obtained on both missions, and exposed to space environment from its early developmental stages. Morphology of the embryos was found not deviated from those developed on ground, as long as in the images taken in orbit or the examined specimen retrieved to ground. On the other hand, pathological changes were discovered in several organs of the adult newts that returned alive from their space flight.

  18. Cryptic crested newt diversity at the Eurasian transition: the mitochondrial DNA phylogeography of Near Eastern Triturus newts.

    PubMed

    Wielstra, B; Themudo, G Espregueira; Güçlü, O; Olgun, K; Poyarkov, N A; Arntzen, J W

    2010-09-01

    Crested newts of the Triturus karelinii group occur in a phylogeographically understudied region: the Near East. Controversy surrounds the systematic position of these newts within the complete crested newt assemblage (the Triturus cristatus superspecies). We explore the situation using mitochondrial sequence data (ND2 and ND4, approximately 1.7kb) and employing different methods of phylogenetic inference (Bayesian inference and Maximum Likelihood using mixed models) and molecular dating (r8s and BEAST). The T. karelinii group is monophyletic and constitutes one of four main lineages in the T. cristatus superspecies. The separation of the T. karelinii group from the remaining crested newts around 9Ma is related to the formation of the Mid-Aegean Trench, which separated the Balkan and Anatolian landmasses. The T. karelinii group comprises three geographically structured clades (eastern, central and western). The genetic divergence shown by these clades is comparable to that among recognized crested newt species. We suggest the uplift of the Armenian Plateau to be responsible for the separation of the eastern clade around 7Ma, and the re-establishment of a marine connection between the Black Sea and the Mediterranean at the end of the Messinian Salinity Crisis to have caused the split between the central and western clade around 5.5Ma. Genetic structuring within the three clades dates to the Quaternary Ice Age (<2.59Ma) and is associated with alternating periods of isolation and reconnection caused by periodic changes in sea level and surface runoff.

  19. A developmentally regulated switch from stem cells to dedifferentiation for limb muscle regeneration in newts.

    PubMed

    Tanaka, Hibiki Vincent; Ng, Nathaniel Chuen Yin; Yang Yu, Zhan; Casco-Robles, Martin Miguel; Maruo, Fumiaki; Tsonis, Panagiotis A; Chiba, Chikafumi

    2016-01-01

    The newt, a urodele amphibian, is able to repeatedly regenerate its limbs throughout its lifespan, whereas other amphibians deteriorate or lose their ability to regenerate limbs after metamorphosis. It remains to be determined whether such an exceptional ability of the newt is either attributed to a strategy, which controls regeneration in larvae, or on a novel one invented by the newt after metamorphosis. Here we report that the newt switches the cellular mechanism for limb regeneration from a stem/progenitor-based mechanism (larval mode) to a dedifferentiation-based one (adult mode) as it transits beyond metamorphosis. We demonstrate that larval newts use stem/progenitor cells such as satellite cells for new muscle in a regenerated limb, whereas metamorphosed newts recruit muscle fibre cells in the stump for the same purpose. We conclude that the newt has evolved novel strategies to secure its regenerative ability of the limbs after metamorphosis. PMID:27026263

  20. A developmentally regulated switch from stem cells to dedifferentiation for limb muscle regeneration in newts.

    PubMed

    Tanaka, Hibiki Vincent; Ng, Nathaniel Chuen Yin; Yang Yu, Zhan; Casco-Robles, Martin Miguel; Maruo, Fumiaki; Tsonis, Panagiotis A; Chiba, Chikafumi

    2016-03-30

    The newt, a urodele amphibian, is able to repeatedly regenerate its limbs throughout its lifespan, whereas other amphibians deteriorate or lose their ability to regenerate limbs after metamorphosis. It remains to be determined whether such an exceptional ability of the newt is either attributed to a strategy, which controls regeneration in larvae, or on a novel one invented by the newt after metamorphosis. Here we report that the newt switches the cellular mechanism for limb regeneration from a stem/progenitor-based mechanism (larval mode) to a dedifferentiation-based one (adult mode) as it transits beyond metamorphosis. We demonstrate that larval newts use stem/progenitor cells such as satellite cells for new muscle in a regenerated limb, whereas metamorphosed newts recruit muscle fibre cells in the stump for the same purpose. We conclude that the newt has evolved novel strategies to secure its regenerative ability of the limbs after metamorphosis.

  1. A developmentally regulated switch from stem cells to dedifferentiation for limb muscle regeneration in newts

    PubMed Central

    Tanaka, Hibiki Vincent; Ng, Nathaniel Chuen Yin; Yang Yu, Zhan; Casco-Robles, Martin Miguel; Maruo, Fumiaki; Tsonis, Panagiotis A.; Chiba, Chikafumi

    2016-01-01

    The newt, a urodele amphibian, is able to repeatedly regenerate its limbs throughout its lifespan, whereas other amphibians deteriorate or lose their ability to regenerate limbs after metamorphosis. It remains to be determined whether such an exceptional ability of the newt is either attributed to a strategy, which controls regeneration in larvae, or on a novel one invented by the newt after metamorphosis. Here we report that the newt switches the cellular mechanism for limb regeneration from a stem/progenitor-based mechanism (larval mode) to a dedifferentiation-based one (adult mode) as it transits beyond metamorphosis. We demonstrate that larval newts use stem/progenitor cells such as satellite cells for new muscle in a regenerated limb, whereas metamorphosed newts recruit muscle fibre cells in the stump for the same purpose. We conclude that the newt has evolved novel strategies to secure its regenerative ability of the limbs after metamorphosis. PMID:27026263

  2. Effects of overtraining on extinction in newts (Cynops pyrrhogaster).

    PubMed

    Shibasaki, Masahiro; Ishida, Masato

    2012-11-01

    The overtraining extinction effect (OEE), a phenomenon in which extended training facilitates extinction, has been found in mammals and reptiles. However, fish have never shown OEE. No study has yet investigated OEE in newts, a representative amphibian species. We tested whether newts, Cynops pyrrhogaster, show OEE in a straight-array task. All animals received five trials per day and were given a piece of dried worm during reinforced trials. They showed significant acquisition and extinction effects in reinforced and nonreinforced trials. However, we found no difference in extinction performance between a group with 25-trial acquisition and one with 75-trial acquisition, suggesting that OEE was not found in newts. OEE has generally been explained in terms of frustration-related mechanisms. Our results suggest that emotional reactions to nonreward, such as frustration, may not influence behavior in amphibians.

  3. Expression of stem cell pluripotency factors during regeneration in newts.

    PubMed

    Maki, Nobuyasu; Suetsugu-Maki, Rinako; Tarui, Hiroshi; Agata, Kiyokazu; Del Rio-Tsonis, Katia; Tsonis, Panagiotis A

    2009-06-01

    In this study, we present data indicating that mammalian stem cell pluripotency-inducing factors are expressed during lens and limb regeneration in newts. The apparent expression even in intact tissues and the ensued regulation during regeneration raises the possibility that these factors might regulate tissue-specific reprogramming and regeneration. Furthermore, these factors should enable us to understand the similarities and differences between animal regeneration in the newt and stem cell strategies in mammals. Developmental Dynamics 238:1613-1616, 2009. (c) 2009 Wiley-Liss, Inc.

  4. [The role of osteoclasts in maintaining calcium homeostasis in newts].

    PubMed

    Berezovskaia, O P; Rodionova, N V; Grigorian, E N; Mitashov, V I

    1997-01-01

    The intensity of osteoclastic resorption and calcium contact were investigated in intact limb bones of the newts flown onboard of biosatellite Cosmos-2229 after amputation of their forelimbs and tail. X-ray microanalysis has shown an increase of calcium content in the bones on the 20th day after operation. Histological study revealed activated osteoclastic resorption on the inner surface of long bones. The newts exposed to weightlessness after the operation had the same level of bone mineralization as the operated ground control ones, but the number of polynuclear osteoclasts increased to a lesser extent.

  5. [Morphogenetic changes during newt tail regeneration under changed gravity conditions].

    PubMed

    Radugina, E A; Grigorian, É N

    2012-01-01

    Gravity-dependent shape alterations in newt tail regenerates are described, which were previously noticed in experiments onboard satellites Foton M2, M3 and in corresponding laboratory controls. Laboratory conditions were developed that allow reproducing this phenomenon persistently in the adult newts Pleurodeles waltl (Michahelles, 1830). The newts kept in an aquarium (in partial weightlessness) after 1/3 tail amputation developed normal lanceolate regenerates, while those that stayed on a moist mat (exposed to greater gravity than in aquarium) developed curved tail regenerates. Dynamics of the shape alterations were described using computer morphometric analysis. The curve was shown to develop at stage III of regeneration and to be caused by bending of the developing axial structures: the ependymal tube and the cartilage rode. Cellular processes were described that accompany the tail shape changes, such as cell migration and formation of dense aggregates. Unequal proliferation throughout the wound epidermis and blastema was revealed using BrdU assay. Proliferation increased within dorsal and apical regions of the regenerates in the newts kept on the mat cell compared with the aquarian animals. PMID:23136735

  6. Spaceflight Effects on the Hematopoietic Tissue of Ribbed Newts

    NASA Astrophysics Data System (ADS)

    Domaratskaya, E. I.; Almeida, E. A. C.; Butorina, N. N.; Nikonova, T. M.; Grigoryan, E. N.; Poplinskaya, V. A.

    2008-06-01

    The newts Pleurodeles waltl flown on Foton-M2 for 12 days were used for studying the effects of spaceflight on hematopoiesis in lower vertebrates. Prior to the flight, all the animals underwent to removal their lenses and tail tips for regeneration studies. No significant differences in blood cell contents were detected between flight and control animals. Morphological examination of hematopoietic areas of the liver in both groups also showed no significant differences. Experiments with BrdU incorporation revealed labeled cells in the hemopoietic area of the liver as well as in blood. The blood cell composition of newts flown on Foton-M3 was similar to that in intact (nonoperated) newts used in Bion-11 and Foton-M2 experiments. The lack of blood changes in newts during the current experiments distinguishes them from mammals flown in space (rats and mice), which developed significant changes in both blood cell counts, stem and committed cells in the blood-forming tissues.

  7. [Morphogenetic changes during newt tail regeneration under changed gravity conditions].

    PubMed

    Radugina, E A; Grigorian, É N

    2012-01-01

    Gravity-dependent shape alterations in newt tail regenerates are described, which were previously noticed in experiments onboard satellites Foton M2, M3 and in corresponding laboratory controls. Laboratory conditions were developed that allow reproducing this phenomenon persistently in the adult newts Pleurodeles waltl (Michahelles, 1830). The newts kept in an aquarium (in partial weightlessness) after 1/3 tail amputation developed normal lanceolate regenerates, while those that stayed on a moist mat (exposed to greater gravity than in aquarium) developed curved tail regenerates. Dynamics of the shape alterations were described using computer morphometric analysis. The curve was shown to develop at stage III of regeneration and to be caused by bending of the developing axial structures: the ependymal tube and the cartilage rode. Cellular processes were described that accompany the tail shape changes, such as cell migration and formation of dense aggregates. Unequal proliferation throughout the wound epidermis and blastema was revealed using BrdU assay. Proliferation increased within dorsal and apical regions of the regenerates in the newts kept on the mat cell compared with the aquarian animals.

  8. Relationships between spleen and respiration in the newt.

    PubMed

    Frangioni, G; Borgioli, G

    1989-11-01

    Specimens of newt, Triturus cristatus carnifex (Laurenti), anesthetized by submersion in 0.2% chlorbutol in tap water for 15 min, and then placed out of water in a damp terrarium, show hypertrophy of the spleen that in 2 hr gradually increases from 0.31 +/- 0.12%with respect to body weight to 1.56 +/- 0.26% (means and standard deviation calculated for groups of six animals). Other anesthetics either do not produce hypnosis (Veronal), do not have a prolonged enough effect (ethyl ether, chloroform), or induce vasodilatation, which prevents hypertrophy (MS-222, urethane). The spleen hypertrophy, seen histologically to be due exclusively to blood congestion, is not caused by either a pharmacological effect of the chlorbutol or by the hypnotic state, as it does not appear in submerged anesthetized animals, unless the water is constantly stirred by a magnetic agitator, and can be reversed depending on the ventilation of the animal's skin. The spleen hoards blood when oxygenation is good (in air or stirred water) and releases this supply in the bloodstream when oxygenation is insufficient (in still water). The hypoxic "diffusion boundary layer," which, in still water, forms around the immobile newts, hampers respiratory exchange and stimulates the spleen contraction. This mechanism and its relationship to oxygenation has been demonstrated statistically in unanesthetized newts as well, in both air and water, despite the interference of two contrasting factors--lung respiration and spontaneous motor activity--absent in anesthesized animals. Congestion and decongestion of the spleen are the physiological mechanisms compensating for variations in the level of oxygenation, an alternative to the "capillary recruitment" described by Poczopko and Burggren and Moalli in may amphibians that appears to be absent in newts. The newt spleen, known to play a lesser role in erythropoiesis and destruction of aged erythrocytes than that traditionally assigned to it is thus of primary

  9. Blood and clonogenic hemopoietic cells of newts after the space flight

    NASA Astrophysics Data System (ADS)

    Michurina, T. V.; Domaratskaya, E. I.; Nikonova, T. M.; Khrushchov, N. G.

    Ribbed newts were used for studying the effect of space flight on board of the biosatellite (Cosmos-2229) on blood and clonogenic hemopoietic cells. In blood of newts of the flight group, the relative proportion of neutrophils increased, whereas that of lymphocytes and eosinophils decreased. Space flight did not result in loss of the ability of newt blood cells to incorporate H^3-thymidine. Analysis of clonogenic hemopoietic cells was performed using the method of hemopoietic colony formation on cellulose acetate membranes implanted into the peritoneal cavity of irradiated newts. To analyze reconstitution of hemopoiesis after irradiation donor hemopoietic cells from flight or control newts were transplanted into irradiated newts whose hemopoietic organs were investigated. The newt can be considered an adequate model for studying hemopoiesis under the conditions of the space flight. Previous studies on rats subjected to 5- to 19-day space flights revealed a decrease in the number of clonogenic cells in their hemopoietic organs accompanied by specific changes in the precursor cell compartment and in blood /1,2/. Hence, it was interesting to analyze blood and hemopoietic tissue of lower vertebrates after a space flight and to compare the response to it of animals belonging to different taxonomic groups. We analyzed blood and clonogenic hemopoietic cells of ribbed newts, Pleurodeles waltl (age one year, weight 20-28 g) subjected to a 12-day space flight on board of a Cosmos-2229 biosatellite. The same animals were used in studies on limb and lens regeneration. The results were compared with those obtained with control groups of newts: (1) basic control, operated newts sacrificed on the day of biosatellite launching (BC); (2) synchronous control, operated newts kept in the laboratory under simulated space flight conditions (SC); and (3) intact newts (IC).

  10. A highly divergent picornavirus in an amphibian, the smooth newt (Lissotriton vulgaris).

    PubMed

    Reuter, Gábor; Boros, Ákos; Tóth, Zoltán; Gia Phan, Tung; Delwart, Eric; Pankovics, Péter

    2015-09-01

    Genetically highly divergent picornavirus (Newt/2013/HUN, KP770140) was detected using viral metagenomics in faecal samples of free-living smooth newts (Lissotriton vulgaris). Newt picornavirus was identified by reverse transcription-polymerase chain reaction (RT-PCR) in six (25 %) of the 24 samples originating from individuals caught in two out of the six investigated natural ponds in Hungary. The first picornavirus in amphibians expands the host range of members of the Picornaviridae, and opens a new research field in picornavirus evolution in lower vertebrates. Newt picornavirus represents a novel species in a novel genus within the family Picornaviridae, provisionally named genus Ampivirus (amphibian picornavirus). PMID:26018961

  11. A highly divergent picornavirus in an amphibian, the smooth newt (Lissotriton vulgaris)

    PubMed Central

    Boros, Ákos; Tóth, Zoltán; Gia Phan, Tung; Delwart, Eric; Pankovics, Péter

    2015-01-01

    Genetically highly divergent picornavirus (Newt/2013/HUN, KP770140) was detected using viral metagenomics in faecal samples of free-living smooth newts (Lissotriton vulgaris). Newt picornavirus was identified by reverse transcription-polymerase chain reaction (RT-PCR) in six (25 %) of the 24 samples originating from individuals caught in two out of the six investigated natural ponds in Hungary. The first picornavirus in amphibians expands the host range of members of the Picornaviridae, and opens a new research field in picornavirus evolution in lower vertebrates. Newt picornavirus represents a novel species in a novel genus within the family Picornaviridae, provisionally named genus Ampivirus (amphibian picornavirus). PMID:26018961

  12. A highly divergent picornavirus in an amphibian, the smooth newt (Lissotriton vulgaris).

    PubMed

    Reuter, Gábor; Boros, Ákos; Tóth, Zoltán; Gia Phan, Tung; Delwart, Eric; Pankovics, Péter

    2015-09-01

    Genetically highly divergent picornavirus (Newt/2013/HUN, KP770140) was detected using viral metagenomics in faecal samples of free-living smooth newts (Lissotriton vulgaris). Newt picornavirus was identified by reverse transcription-polymerase chain reaction (RT-PCR) in six (25 %) of the 24 samples originating from individuals caught in two out of the six investigated natural ponds in Hungary. The first picornavirus in amphibians expands the host range of members of the Picornaviridae, and opens a new research field in picornavirus evolution in lower vertebrates. Newt picornavirus represents a novel species in a novel genus within the family Picornaviridae, provisionally named genus Ampivirus (amphibian picornavirus).

  13. Ghrelin receptor in Japanese fire belly newt, Cynops pyrrhogaster.

    PubMed

    Kaiya, Hiroyuki; Kangawa, Kenji; Miyazato, Mikiya

    2015-11-01

    We identified cDNA encoding a functional ghrelin receptor (growth hormone secretagogue-receptor 1a (GHS-R1a)) in a urodele amphibian, the Japanese fire belly newt (Cynops pyrrhogaster). Two functional receptor proteins, composed of 378- and 362-amino acids, were deduced from the identified cDNA because two candidate initiation methionine sites were found. The long-chain receptor protein shared 80%, 69%, and 59% identities with the bullfrog GHS-R1a, human GHS-R1a and tilapia GHS-R1a-like receptor, respectively. Phylogenetic analysis suggested that the newt receptor is grouped to the clade of the tetrapod homologs, and very closed to anuran amphibians. In functional analyses, homologous newt ghrelin, heterologous bullfrog and rat ghrelin, and a GHS-R1a agonist, GHRP-6 increased intracellular Ca(2+) concentration in human embryonic kidney (HEK) 293 cells stably expressed newt GHS-R1a. The responsiveness was much greater in the short-chain receptor than in the long-chain receptor. Both receptors preferred to bind Ser(3)-ghrelin including newt and rat ghrelin than Thr(3)-ghrelin with bullfrog ghrelin. GHRP-6 has a similar affinity to bullfrog ghrelin. GHS-R1a mRNA was expressed in the brain, pituitary, intestine, pancreas, testis and fat body with high level, and eyes, heart, stomach, liver, gall bladder, kidney and dorsal skin with low level. In a fasting experiment, gene expression of GHS-R1a in the brain and pituitary increased 4days after fasting, and the increased level decreased to the initial level 2weeks after fasting. These changes are consistent with the change in ghrelin mRNA. In contrast, expression of ghrelin and GHS-R1a mRNA in the stomach decreased on day 4 after fasting, and increased 2weeks after fasting. These results indicate that ghrelin and its receptor system are present and altered by energy states in this newt. PMID:26172570

  14. Newt limb regeneration studied with synchrotron micro-CT

    NASA Astrophysics Data System (ADS)

    Stock, Stuart R.; Ignatiev, Konstantin I.; Simon, Hans-Georg; De Carlo, Francesco

    2004-10-01

    Newts are the most developed vertebrates which retain the ability as adults to regenerate missing limbs; they are, therefore, of great interest in terms understanding how such regeneration could be triggered in mammals. In this study, synchrotron microCT was used to study bone microstructure in control forelimbs and in forelimbs regenerated for periods from 37 to 85 days. The bone microstructure in newts has been largely neglected, and interesting patterns within the original bone and in the regenerating arm and hand are described. Periosteal bone formation in the regenerating arm and finger bones, delayed ossification of carpal (but not metacarpal) bones and the complex microstructure of the original carpal bones are areas where microCT reveals detail of particular interest.

  15. Atomic force microscope observations of otoconia in the newt

    NASA Technical Reports Server (NTRS)

    Hallworth, R.; Wiederhold, M. L.; Campbell, J. B.; Steyger, P. S.

    1995-01-01

    Calcitic and aragonitic otoconia from the Japanese red-bellied newt, Cynops pyrrhogaster, were examined using an atomic force microscope. The surface structure of both otoconial polymorphs consisted of arrays of elements approximately 50 nm in diameter. Elements were generally round and were separated by shallow depressions of no more than 20 nm. The elements are suggested to be single crystals of calcium carbonate. The relationship of these observations to theories of otoconial genesis is discussed.

  16. [Photoreceptors and visual pigments in three species of newts].

    PubMed

    Koremiak, D A; Govardovskiĭ, V I

    2013-01-01

    Photoreceptor complement and retinal visual pigments in three newt (Caudata, Salamandridae, Pleurodelinae) species (Pleurodeles waltl, Lissotriton (Triturus) vulgaris and Cynops orientalis) were studied by light mucroscopy and microspectrophotometry. Retinas of all three species contain "red" (rhodopsin/porphyropsin) rods, large and small single cones, and double cones. Large single cones and both components of double cones contain red-sensitive (presumably LWS) visual pigment whose absorbance spectrum peaks between 593 and 611 nm. Small single cones are either blue- (SWS2, maximum absorbance between 470 and 489 nm) or UV-sensitive (SWS1, maximum absorbance between 340 and 359 nm). Chromophore composition of visual pigments (A1 vs. A2) was assessed both from template fitting of absorption spectra and by the method of selective bleaching. All pigments contained a mixture of A1 (11-cis retinal) and A2 (11-cis-3,4-dehydroretinal) chromophore in the proportion depending on the species and cell type. In all cases, A2 was dominant. However, in C. orientalis rods the fraction of A1 could reach 45%, while in P. waltl and L. vulgaris cones it did not exceed 5%. Remarkably, the absorbance of the newt blue-sensitive visual pigment was shifted by up to 45 nm toward the longer wavelength, as compared with all other amphibian SWS2-pigments. We found no "green" rods typical of retinas of Anura and some Caudata (ambystomas) in the three newt species studied. PMID:24459859

  17. [Photoreceptors and visual pigments in three species of newts].

    PubMed

    Koremiak, D A; Govardovskiĭ, V I

    2013-01-01

    Photoreceptor complement and retinal visual pigments in three newt (Caudata, Salamandridae, Pleurodelinae) species (Pleurodeles waltl, Lissotriton (Triturus) vulgaris and Cynops orientalis) were studied by light mucroscopy and microspectrophotometry. Retinas of all three species contain "red" (rhodopsin/porphyropsin) rods, large and small single cones, and double cones. Large single cones and both components of double cones contain red-sensitive (presumably LWS) visual pigment whose absorbance spectrum peaks between 593 and 611 nm. Small single cones are either blue- (SWS2, maximum absorbance between 470 and 489 nm) or UV-sensitive (SWS1, maximum absorbance between 340 and 359 nm). Chromophore composition of visual pigments (A1 vs. A2) was assessed both from template fitting of absorption spectra and by the method of selective bleaching. All pigments contained a mixture of A1 (11-cis retinal) and A2 (11-cis-3,4-dehydroretinal) chromophore in the proportion depending on the species and cell type. In all cases, A2 was dominant. However, in C. orientalis rods the fraction of A1 could reach 45%, while in P. waltl and L. vulgaris cones it did not exceed 5%. Remarkably, the absorbance of the newt blue-sensitive visual pigment was shifted by up to 45 nm toward the longer wavelength, as compared with all other amphibian SWS2-pigments. We found no "green" rods typical of retinas of Anura and some Caudata (ambystomas) in the three newt species studied.

  18. Mechanism of Action of Secreted Newt Anterior Gradient Protein

    PubMed Central

    Grassme, Kathrin S.; Garza-Garcia, Acely; Delgado, Jean-Paul; Godwin, James W.; Kumar, Anoop; Gates, Phillip B.; Brockes, Jeremy P.

    2016-01-01

    Anterior gradient (AG) proteins have a thioredoxin fold and are targeted to the secretory pathway where they may act in the ER, as well as after secretion into the extracellular space. A newt member of the family (nAG) was previously identified as interacting with the GPI-anchored salamander-specific three-finger protein called Prod1. Expression of nAG has been implicated in the nerve dependence of limb regeneration in salamanders, and nAG acted as a growth factor for cultured newt limb blastemal (progenitor) cells, but the mechanism of action was not understood. Here we show that addition of a peptide antibody to Prod1 specifically inhibit the proliferation of blastema cells, suggesting that Prod1 acts as a cell surface receptor for secreted nAG, leading to S phase entry. Mutation of the single cysteine residue in the canonical active site of nAG to alanine or serine leads to protein degradation, but addition of residues at the C terminus stabilises the secreted protein. The mutation of the cysteine residue led to no detectable activity on S phase entry in cultured newt limb blastemal cells. In addition, our phylogenetic analyses have identified a new Caudata AG protein called AG4. A comparison of the AG proteins in a cell culture assay indicates that nAG secretion is significantly higher than AGR2 or AG4, suggesting that this property may vary in different members of the family. PMID:27100463

  19. Mechanism of Action of Secreted Newt Anterior Gradient Protein.

    PubMed

    Grassme, Kathrin S; Garza-Garcia, Acely; Delgado, Jean-Paul; Godwin, James W; Kumar, Anoop; Gates, Phillip B; Driscoll, Paul C; Brockes, Jeremy P

    2016-01-01

    Anterior gradient (AG) proteins have a thioredoxin fold and are targeted to the secretory pathway where they may act in the ER, as well as after secretion into the extracellular space. A newt member of the family (nAG) was previously identified as interacting with the GPI-anchored salamander-specific three-finger protein called Prod1. Expression of nAG has been implicated in the nerve dependence of limb regeneration in salamanders, and nAG acted as a growth factor for cultured newt limb blastemal (progenitor) cells, but the mechanism of action was not understood. Here we show that addition of a peptide antibody to Prod1 specifically inhibit the proliferation of blastema cells, suggesting that Prod1 acts as a cell surface receptor for secreted nAG, leading to S phase entry. Mutation of the single cysteine residue in the canonical active site of nAG to alanine or serine leads to protein degradation, but addition of residues at the C terminus stabilises the secreted protein. The mutation of the cysteine residue led to no detectable activity on S phase entry in cultured newt limb blastemal cells. In addition, our phylogenetic analyses have identified a new Caudata AG protein called AG4. A comparison of the AG proteins in a cell culture assay indicates that nAG secretion is significantly higher than AGR2 or AG4, suggesting that this property may vary in different members of the family. PMID:27100463

  20. Amphibian skin may select for rare environmental microbes.

    PubMed

    Walke, Jenifer B; Becker, Matthew H; Loftus, Stephen C; House, Leanna L; Cormier, Guy; Jensen, Roderick V; Belden, Lisa K

    2014-11-01

    Host-microbe symbioses rely on the successful transmission or acquisition of symbionts in each new generation. Amphibians host a diverse cutaneous microbiota, and many of these symbionts appear to be mutualistic and may limit infection by the chytrid fungus, Batrachochytrium dendrobatidis, which has caused global amphibian population declines and extinctions in recent decades. Using bar-coded 454 pyrosequencing of the 16S rRNA gene, we addressed the question of symbiont transmission by examining variation in amphibian skin microbiota across species and sites and in direct relation to environmental microbes. Although acquisition of environmental microbes occurs in some host-symbiont systems, this has not been extensively examined in free-living vertebrate-microbe symbioses. Juvenile bullfrogs (Rana catesbeiana), adult red-spotted newts (Notophthalmus viridescens), pond water and pond substrate were sampled at a single pond to examine host-specificity and potential environmental transmission of microbiota. To assess population level variation in skin microbiota, adult newts from two additional sites were also sampled. Cohabiting bullfrogs and newts had distinct microbial communities, as did newts across the three sites. The microbial communities of amphibians and the environment were distinct; there was very little overlap in the amphibians' core microbes and the most abundant environmental microbes, and the relative abundances of OTUs that were shared by amphibians and the environment were inversely related. These results suggest that, in a host species-specific manner, amphibian skin may select for microbes that are generally in low abundance in the environment.

  1. Amphibian skin may select for rare environmental microbes

    PubMed Central

    Walke, Jenifer B; Becker, Matthew H; Loftus, Stephen C; House, Leanna L; Cormier, Guy; Jensen, Roderick V; Belden, Lisa K

    2014-01-01

    Host-microbe symbioses rely on the successful transmission or acquisition of symbionts in each new generation. Amphibians host a diverse cutaneous microbiota, and many of these symbionts appear to be mutualistic and may limit infection by the chytrid fungus, Batrachochytrium dendrobatidis, which has caused global amphibian population declines and extinctions in recent decades. Using bar-coded 454 pyrosequencing of the 16S rRNA gene, we addressed the question of symbiont transmission by examining variation in amphibian skin microbiota across species and sites and in direct relation to environmental microbes. Although acquisition of environmental microbes occurs in some host-symbiont systems, this has not been extensively examined in free-living vertebrate-microbe symbioses. Juvenile bullfrogs (Rana catesbeiana), adult red-spotted newts (Notophthalmus viridescens), pond water and pond substrate were sampled at a single pond to examine host-specificity and potential environmental transmission of microbiota. To assess population level variation in skin microbiota, adult newts from two additional sites were also sampled. Cohabiting bullfrogs and newts had distinct microbial communities, as did newts across the three sites. The microbial communities of amphibians and the environment were distinct; there was very little overlap in the amphibians' core microbes and the most abundant environmental microbes, and the relative abundances of OTUs that were shared by amphibians and the environment were inversely related. These results suggest that, in a host species-specific manner, amphibian skin may select for microbes that are generally in low abundance in the environment. PMID:24858782

  2. The newt (Cynops pyrrhogaster) RPE65 promoter: molecular cloning, characterization and functional analysis.

    PubMed

    Casco-Robles, Martin Miguel; Miura, Tomoya; Chiba, Chikafumi

    2015-06-01

    The adult newt has the ability to regenerate the neural retina following injury, a process achieved primarily by the retinal pigment epithelium (RPE). To deliver exogenous genes to the RPE for genetic manipulation of regenerative events, we isolated the newt RPE65 promoter region by genome walking. First, we cloned the 2.8 kb RPE65 promoter from the newt, Cynops pyrrhogaster. Sequence analysis revealed several conserved regulatory elements described previously in mouse and human RPE65 promoters. Second, having previously established an I-SceI-mediated transgenic protocol for the newt, we used it here to examine the -657 bp proximal promoter of RPE65. The promoter assay used with F0 transgenic newts confirmed transgene expression of mCherry fluorescent protein in the RPE. Using bioinformatic tools and the TRANSFAC database, we identified a 340 bp CpG island located between -635 and -296 bp in the promoter; this region contains response elements for the microphthalmia-associated transcription factor known as MITF (CACGTG, CATGTG), and E-boxes (CANNTG). Sex-determining region box 9 (or SOX9) response element previously reported in the regulation of RPE genes (including RPE65) was also identified in the newt RPE65 promoter. Third, we identified DNA motif boxes in the newt RPE65 promoter that are conserved among other vertebrates. The newt RPE65 promoter is an invaluable tool for site-specific delivery of exogenous genes or genetic manipulation systems for the study of retinal regeneration in this animal.

  3. Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, Ferocactus viridescens.

    PubMed

    LeVan, Katherine E; Hung, Keng-Lou James; McCann, Kyle R; Ludka, John T; Holway, David A

    2014-01-01

    Mounting evidence indicates that trade-offs between plant defense and reproduction arise not only from resource allocation but also from interactions among mutualists. Indirect costs of plant defense by ants, for example, can outweigh benefits if ants deter pollinators. Plants can dissuade ants from occupying flowers, but such arrangements may break down when novel ant partners infiltrate mutualisms. Here, we examine how floral visitation by ants affects pollination services when the invasive Argentine ant (Linepithema humile) replaces a native ant species in a food-for-protection mutualism with the coast barrel cactus (Ferocactus viridescens), which, like certain other barrel cacti, produces extrafloral nectar. We compared the effects of floral visitation by the Argentine ant with those of the most prevalent native ant species (Crematogaster californica). Compared to C. californica, the Argentine ant was present in higher numbers in flowers. Cactus bees (Diadasia spp.), the key pollinators in this system, spent less time in flowers when cacti were occupied by the Argentine ant compared to when cacti were occupied by C. californica. Presumably as a consequence of decreased duration of floral visits by Diadasia, cacti occupied by L. humile set fewer seeds per fruit and produced fewer seeds overall compared to cacti occupied by C. californica. These data illustrate the importance of mutualist identity in cases where plants balance multiple mutualisms. Moreover, as habitats become increasingly infiltrated by introduced species, the loss of native mutualists and their replacement by non-native species may alter the shape of trade-offs between plant defense and reproduction.

  4. A robust transcriptional program in newts undergoing multiple events of lens regeneration throughout their lifespan.

    PubMed

    Sousounis, Konstantinos; Qi, Feng; Yadav, Manisha C; Millán, José Luis; Toyama, Fubito; Chiba, Chikafumi; Eguchi, Yukiko; Eguchi, Goro; Tsonis, Panagiotis A

    2015-01-01

    Newts have the ability to repeatedly regenerate their lens even during ageing. However, it is unclear whether this regeneration reflects an undisturbed genetic activity. To answer this question, we compared the transcriptomes of lenses, irises and tails from aged newts that had undergone lens regeneration 19 times with the equivalent tissues from young newts that had never experienced lens regeneration. Our analysis indicates that repeatedly regenerated lenses showed a robust transcriptional program comparable to young never-regenerated lenses. In contrast, the tail, which was never regenerated, showed gene expression signatures of ageing. Our analysis strongly suggests that, with respect to gene expression, the regenerated lenses have not deviated from a robust transcriptional program even after multiple events of regeneration throughout the life of the newt. In addition, our study provides a new paradigm in biology, and establishes the newt as a key model for the study of regeneration in relation to ageing. PMID:26523389

  5. A robust transcriptional program in newts undergoing multiple events of lens regeneration throughout their lifespan.

    PubMed

    Sousounis, Konstantinos; Qi, Feng; Yadav, Manisha C; Millán, José Luis; Toyama, Fubito; Chiba, Chikafumi; Eguchi, Yukiko; Eguchi, Goro; Tsonis, Panagiotis A

    2015-11-02

    Newts have the ability to repeatedly regenerate their lens even during ageing. However, it is unclear whether this regeneration reflects an undisturbed genetic activity. To answer this question, we compared the transcriptomes of lenses, irises and tails from aged newts that had undergone lens regeneration 19 times with the equivalent tissues from young newts that had never experienced lens regeneration. Our analysis indicates that repeatedly regenerated lenses showed a robust transcriptional program comparable to young never-regenerated lenses. In contrast, the tail, which was never regenerated, showed gene expression signatures of ageing. Our analysis strongly suggests that, with respect to gene expression, the regenerated lenses have not deviated from a robust transcriptional program even after multiple events of regeneration throughout the life of the newt. In addition, our study provides a new paradigm in biology, and establishes the newt as a key model for the study of regeneration in relation to ageing.

  6. Diurnal changes in the synthesis of the neurosteroid 7alpha-hydroxypregnenolone stimulating locomotor activity in newts.

    PubMed

    Koyama, Teppei; Haraguchi, Shogo; Vaudry, Hubert; Tsutsui, Kazuyoshi

    2009-04-01

    We recently identified 7alpha-hydroxypregnenolone as a novel amphibian neurosteroid stimulating locomotor activity in newts. Because male newts show marked diurnal changes in locomotor activity, we hypothesized that 7alpha-hydroxypregnenolone may be a key factor for the induction of diurnal changes in locomotor activity in male newts. In this study, we found diurnal changes in 7alpha-hydroxypregnenolone synthesis in the brain of male newts, which paralleled locomotor activity. Interestingly, the production of 7alpha-hydroxypregnenolone in the male newt brain increased during the dark phase when locomotor activity of males was high.

  7. Seasonal changes in the synthesis of the neurosteroid 7alpha-hydroxypregnenolone stimulating locomotor activity in newts.

    PubMed

    Haraguchi, Shogo; Matsunaga, Masahiro; Koyama, Teppei; Do Rego, Jean-Luc; Tsutsui, Kazuyoshi

    2009-04-01

    We recently found that the newt brain actively produces 7alpha-hydroxypregnenolone, a novel amphibian neurosteroid stimulating locomotor activity. It is well known that locomotor activity of male newts increases during the breeding period. To understand the physiological role of 7alpha-hydroxypregnenolone, we investigated seasonal changes in 7alpha-hydroxypregnenolone synthesis in the brain of male newts. Interestingly, 7alpha-hydroxypregnenolone synthesis in the brain showed marked changes during the annual breeding cycle, with a maximal level in the breeding period when locomotor activity of male newts increases. These results suggest that 7alpha-hydroxypregnenolone induces seasonal locomotor changes in male newts.

  8. Asymmetric female preferences for courtship pheromones in two closely-related newt species, the smooth newt (Lissotriton vulgaris) and the Carpathian newt (L. montandoni) (Salamandridae).

    PubMed

    Osikowski, Artur

    2012-06-01

    The smooth (Lissotriton vulgaris) and Carpathian (L. montandoni) newts are sister species. These are separated by a moderate genetic distance, but exhibit striking morphological differences, especially in male epigamic traits. In the areas where they co-occur, they readily mate with each other and produce viable hybrids. However, a high level of pre-zygotic isolation with an unknown behavioral basis has been reported. The complex courtship of newts consists of at least three types of modality: chemical, visual, and tactile. The relative significance of these in mate choice is unclear, but it is commonly accepted that pheromones are an important communication channel. The goal of this study was to determine whether the females of L. vulgaris and L. montandoni exhibit preferences for conspecific extracts from the pheromone-producing abdominal (dorsal) glands. Females of both species spent more time in proximity to the source of the abdominal gland extracts of their own species when a liver extract was presented as an alternative. In a second trial, females were simultaneously confronted with conspecific and heterospecific abdominal gland extracts. Asymmetric preferences were found. Lissotriton vulgaris females were not selective, whereas L. montandoni females preferred the conspecific abdominal gland extract. This finding is consistent with the results of earlier experiments on mate choice in these species. The results strongly indicate that pheromones play a crucial role in courtship and species recognition in this pair of closely related, hybridizing species.

  9. Multiple sex pheromone genes are expressed in the abdominal glands of the smooth newt (Lissotriton vulgaris) and Montandon's Newt (L. montandoni) (Salamandridae).

    PubMed

    Artur, Osikowski; Wiesław, Babik; Paweł, Grzmil; Jacek M, Szymura

    2008-06-01

    The smooth newt (Lissotriton "Triturus" vulgaris) and Montandon's newt (L."T." montandoni) are sister species exhibiting pronounced differences in male secondary sexual traits but nevertheless hybridizing and producing fertile hybrids in nature. Since pheromonal communication is an important aspect of the reproductive biology of urodeles, structural differentiation of peptide pheromones and their receptors may contribute to incipient reproductive isolation. The aim of the study was the identification of genes encoding putative courtship pheromone precursors in two newt species and the reconstruction of phylogenetic relationships among them. Our analyses were based on cDNA obtained from the transcripts from the abdominal glands of male newts. We identified five unique cDNA sequences encoding the putative pheromone precursors in L. vulgaris and three additional unique sequences in L. montandoni. The results indicate that in the abdominal glands of Lissotriton newts more than one pheromone-encoding gene is expressed and that these loci form a gene family. Phylogenetic analysis indicates that the divergence of at least some of these genes predates the radiation of European newts.

  10. Proteome analysis of the liver in the Chinese fire-bellied newt Cynops orientalis.

    PubMed

    Zang, X Y; Guo, J L; Geng, X F; Li, P F; Sun, J Y; Wang, Q W; Xu, C S

    2016-01-01

    The Chinese fire-bellied newt, Cynops orientalis, belonging to Amphibia, Caudata, Salamandridae is a species endemic to China. The liver, which is an important digestive gland and the largest amphibian organ, has various functions, including detoxification, glycogen storage, protein synthesis, and hormone production. However, the newt liver has rarely been studied at the molecular level. We performed histomorphology and high-throughput proteomic analysis of the Chinese fire-bellied newt liver, using hematoxylin and eosin (H&E) staining and two-dimensional electrophoresis coupled with mass spectrometry. The H&E staining showed that the newt liver nuclei are large and round, are located in the lateral cytoplasm, and contain a large quantity of lipid droplets. Melanins were abundantly present throughout the hepatic parenchyma. The proteome analysis showed a total of 545 proteins detected in the newt liver. Furthermore, a gene ontology analysis suggested that these proteins were associated with metabolism, immune response, cellular homeostasis, etc. Among these, proteins with metabolic functions were found to be the most abundant and highly expressed. This supports the role of the liver as the metabolic center. The proteomic results provide new insights into the aspects of the liver proteomes of the Chinese fire-bellied newt. The identification of a more global liver proteome in the newt may provide a basis for characterizing and comparing the liver proteomes from other amphibian species. PMID:27525932

  11. The application of eDNA for monitoring of the Great Crested Newt in the UK

    PubMed Central

    Rees, Helen C; Bishop, Keith; Middleditch, David J; Patmore, James R M; Maddison, Ben C; Gough, Kevin C

    2014-01-01

    Current ecological surveys for great crested newts are time-consuming and expensive and can only be carried out within a short survey window. Additional survey methods which would facilitate the detection of rare or protected species such as the great crested newt (Triturus cristatus) would be extremely advantageous. Environmental DNA (eDNA) analysis has been utilized for the detection of great crested newts in Denmark. Here, the same methodology has been applied to water samples taken from UK ponds concurrently with conventional field surveying techniques. Our eDNA analysis exhibited an 84% success rate with a kappa coefficient of agreement between field and eDNA surveys of 0.86. One pond determined to be negative for great crested newt by field survey was positive by eDNA analysis, revealing the potential for improved detection rates using this methodology. Analysis of water samples collected in late summer indicates that eDNA analysis could be used to detect great crested newt after the optimal survey window for current field techniques had passed. Consequently, eDNA analysis could augment currently stipulated techniques for great crested newt surveying as a relatively quick and inexpensive tool for collecting great crested newt presence and distribution data within the UK instead of or prior to full field surveys. PMID:25505530

  12. Hemopoietic tissue in newts flown aboard Foton M3

    NASA Astrophysics Data System (ADS)

    Domaratskaya, Elena I.; Almeida, Eduardo; Butorina, Nina N.; Nikonova, Tatyana M.; Grigoryan, Eleonora N.; Poplinskaya, Valentina A.; Souza, Kenneth; Skidmore, Mike

    The effect of 12-day spaceflight aboard the Foton-M3 biosatellite on the hematopoietic tissue of P. waltl newts was studied. These animals used at the same time in regeneration experiments after lens and tail tip amputation. In flight and synchronous groups there were performed video recording, temperature and radiation monitoring and continuous contact (via skin) with thymidine analog BrdU. We took differential blood counts and assessed histologically the liver in the flight (F), basal (BC) and synchronous (SC)control groups of animals. In the peripheral blood, we identified neutrophils, eosinophils, basophils, lymphocytes, and monocytes. Lymphocytes (L) and neutrophils (N) prevailed, accounting for about 60 and 20% of white blood cells, respectively. The spaceflight had no apparent effect on the differential blood count in the F group: neither the L and N contents nor the maturing to mature N - ratio differed from those in the control groups. No significant differences between F, SC and BC groups were observed with respect to the structure of hematopoietic areas and the liver morphology. As in Foton-M2, BrdU labeled cells revealed in blood as well as in the hemopoietic areas of the liver. However, in previous experiments performed at satellites Bion-10 and Foton-M2 the changes in peripheral blood contents were registered in operated F newts, and we supposed it could be the result of additive effects of spaceflight factors and stimulation of reparative potency and stress due to surgical operation. Possibly, the temperature conditions also may provide some influence on blood cell content of newts that belong to poikilothermic animals. Thus, in present experiment F and SC groups were reared in the same temperature regims, whereas it was nearly 3o C differences between SC and F groups exposed on Foton-M2. At the same time as it was found in experiments on Bion-11 and Foton-M2 spaceflight factors did not affect on differential blood counts of intact non

  13. STS-65 Mission Specialist Thomas with newt in IML-2 module aboard OV-102

    NASA Technical Reports Server (NTRS)

    1994-01-01

    STS-65 Mission Specialist Donald A. Thomas is seen in the spacelab science module at the Rack 1 Workbench making an observation of one of the newts. Smaller organisms, such as the newts, are able to develop from embryos and hatch during the mission as part of an overall program to determine if development occurs normally in the space environment. Temporary home for the newts, the Aquatic Animal Experiment Unit (AAEU) (out of frame) also contained Medaka and goldfish. Thomas joined five other NASA astronauts and a Japanese payload specialist for two weeks of experimenting onboard the Space Shuttle Columbia, Orbiter Vehicle (OV) 102, in Earth orbit.

  14. Constraint and Adaptation in newt Toll-Like Receptor Genes

    PubMed Central

    Babik, Wiesław; Dudek, Katarzyna; Fijarczyk, Anna; Pabijan, Maciej; Stuglik, Michał; Szkotak, Rafał; Zieliński, Piotr

    2015-01-01

    Acute die-offs of amphibian populations worldwide have been linked to the emergence of viral and fungal diseases. Inter and intraspecific immunogenetic differences may influence the outcome of infection. Toll-like receptors (TLRs) are an essential component of innate immunity and also prime acquired defenses. We report the first comprehensive assessment of TLR gene variation for urodele amphibians. The Lissotriton newt TLR repertoire includes representatives of 13 families and is compositionally most similar to that of the anuran Xenopus. Both ancient and recent gene duplications have occurred in urodeles, bringing the total number of TLR genes to at least 21. Purifying selection has predominated the evolution of newt TLRs in both long (∼70 Ma) and medium (∼18 Ma) timescales. However, we find evidence for both purifying and positive selection acting on TLRs in two recently diverged (2–5 Ma) allopatric evolutionary lineages (Lissotriton montandoni and L. vulgaris graecus). Overall, both forms of selection have been stronger in L. v. graecus, while constraint on most TLR genes in L. montandoni appears relaxed. The differences in selection regimes are unlikely to be biased by demographic effects because these were controlled by means of a historical demographic model derived from an independent data set of 62 loci. We infer that TLR genes undergo distinct trajectories of adaptive evolution in closely related amphibian lineages, highlight the potential of TLRs to capture the signatures of different assemblages of pathogenic microorganisms, and suggest differences between lineages in the relative roles of innate and acquired immunity. PMID:25480684

  15. Male Courtship Pheromones Induce Cloacal Gaping in Female Newts (Salamandridae).

    PubMed

    Janssenswillen, Sunita; Bossuyt, Franky

    2016-01-01

    Pheromones are an important component of sexual communication in courting salamanders, but the number of species in which their use has been demonstrated with behavioral evidence remains limited. Here we developed a behavioral assay for demonstrating courtship pheromone use in the aquatically courting Iberian ribbed newt Pleurodeles waltl. By performing an in-depth study of the courtship behavior, we show that females invariably open their cloaca (cloacal gaping) before engaging in pinwheel behavior, the circling movement that is the prelude to spermatophore uptake. In contrast, cloacal gaping was not observed in failed courtships, where females escaped or displayed thanatosis. Since gaping mainly occurred during male amplexus and cloacal imposition, which is the obvious period of pheromone transfer, we next investigated whether male courtship water (i.e., water holding courtship pheromones) alone was able to induce this reaction in females. These tests showed that courtship water induced cloacal gaping significantly more than water, even in the absence of a male. Cloacal gaping thus provides a simple and robust test for demonstrating courtship pheromone use in the Iberian ribbed newt. Since opening the cloaca is an essential prerequisite for spermatophore pick-up in all internally fertilizing salamanders, we hypothesize that variations on this assay will also be useful in several other species. PMID:26771882

  16. Do female newts modify thermoregulatory behavior to manipulate egg size?

    PubMed

    Toufarová, Eliška; Gvoždík, Lumír

    2016-04-01

    Reproductive females manipulate offspring phenotypes by modifying conditions during embryogenesis. In ectotherms, the environmental control over embryogenesis is often realized by changes in maternal thermoregulation during gravidity. To determine if reproduction influences thermoregulatory behavior in species where females lay eggs shortly after fertilization (strict oviparity), we compared preferred body temperatures (Tp) between reproductive (egg-laying) and non-reproductive female newts, Ichthyosaura alpestris. Next, we exposed reproductive females to temperatures mimicking Tp ranges of reproductive and non-reproductive individuals to find out whether the maternally modified thermal regime influences ovum and jelly coat volume, and early cleavage rates at the time of oviposition. In the thermal gradient, reproductive females maintained their body temperatures within a narrower range than non-reproductive individuals. The exposure of ovipositing females to temperatures preferred during their reproductive and non-reproductive period had a negligible influence on egg size and early cleavage rates. We conclude that the modification of maternal thermoregulatory behavior provides a limited opportunity to manipulate egg traits in newts. PMID:27033041

  17. Mothers matter too: benefits of temperature oviposition preferences in newts.

    PubMed

    Kurdíková, Vendula; Smolinský, Radovan; Gvoždík, Lumír

    2011-01-01

    The maternal manipulation hypothesis states that ectothermic females modify thermal conditions during embryonic development to benefit their offspring (anticipatory maternal effect). However, the recent theory suggests that the ultimate currency of an adaptive maternal effect is female fitness that can be maximized also by decreasing mean fitness of individual offspring. We evaluated benefits of temperature oviposition preferences in Alpine newts (Ichthyosaura [formerly Triturus] alpestris) by comparing the thermal sensitivity of maternal and offspring traits across a range of preferred oviposition temperatures (12, 17, and 22°C) and by manipulating the egg-predation risk during oviposition in a laboratory thermal gradient (12-22°C). All traits showed varying responses to oviposition temperatures. Embryonic developmental rates increased with oviposition temperature, whereas hatchling size and swimming capacity showed the opposite pattern. Maternal oviposition and egg-predation rates were highest at the intermediate temperature. In the thermal gradient, females oviposited at the same temperature despite the presence of caged egg-predators, water beetles (Agabus bipustulatus). We conclude that female newts prefer a particular temperature for egg-deposition to maximize their oviposition performance rather than offspring fitness. The evolution of advanced reproductive modes, such as prolonged egg-retention and viviparity, may require, among others, the transition from selfish temperature preferences for ovipositon to the anticipatory maternal effect.

  18. Male Courtship Pheromones Induce Cloacal Gaping in Female Newts (Salamandridae)

    PubMed Central

    Janssenswillen, Sunita; Bossuyt, Franky

    2016-01-01

    Pheromones are an important component of sexual communication in courting salamanders, but the number of species in which their use has been demonstrated with behavioral evidence remains limited. Here we developed a behavioral assay for demonstrating courtship pheromone use in the aquatically courting Iberian ribbed newt Pleurodeles waltl. By performing an in-depth study of the courtship behavior, we show that females invariably open their cloaca (cloacal gaping) before engaging in pinwheel behavior, the circling movement that is the prelude to spermatophore uptake. In contrast, cloacal gaping was not observed in failed courtships, where females escaped or displayed thanatosis. Since gaping mainly occurred during male amplexus and cloacal imposition, which is the obvious period of pheromone transfer, we next investigated whether male courtship water (i.e., water holding courtship pheromones) alone was able to induce this reaction in females. These tests showed that courtship water induced cloacal gaping significantly more than water, even in the absence of a male. Cloacal gaping thus provides a simple and robust test for demonstrating courtship pheromone use in the Iberian ribbed newt. Since opening the cloaca is an essential prerequisite for spermatophore pick-up in all internally fertilizing salamanders, we hypothesize that variations on this assay will also be useful in several other species. PMID:26771882

  19. Microgravity effects on neural retina regeneration in the newt

    NASA Astrophysics Data System (ADS)

    Grigoryan, E. N.; Anton, H. J.; Mitashov, V. I.

    Data on forelimb and eye lens regenerationin in urodeles under spaceflight conditions (SFC) have been obtained in our previous studies. Today, evidence is available that SFC stimulate regeneration in experimental animals rather than inhibit it. The results of control on-ground experiments with simulated microgravity suggest that the stimulatory effect of SFC is due largely to weightlessness. An original experimental model is proposed, which is convenient for comprehensively analyzing neural regeneration under SFC. The initial results described here concern regeneration of neural retina in Pleurodeles waltl newts exposed to microgravity simulated in radial clinostat. After clinorotation for seven days (until postoperation day 16), a positive effect of altered gravity on structural restoration of detached neural retina was confirmed by a number of criteria. Specifically, an increased number of Müllerian glial cells, an increased relative volume of the plexiform layers, reduced cell death, advanced redifferentiation of retinal pigment epithelium, and extended areas of neural retina reattachment were detected in experimental newts. Moreover, cell proliferation in the inner nuclear layer of neural retina increased as compared with control. Thus, low gravity appears to intensify natural cytological and molecular mechanisms of neural retina regeneration in lower vertebrates.

  20. Male Courtship Pheromones Induce Cloacal Gaping in Female Newts (Salamandridae).

    PubMed

    Janssenswillen, Sunita; Bossuyt, Franky

    2016-01-01

    Pheromones are an important component of sexual communication in courting salamanders, but the number of species in which their use has been demonstrated with behavioral evidence remains limited. Here we developed a behavioral assay for demonstrating courtship pheromone use in the aquatically courting Iberian ribbed newt Pleurodeles waltl. By performing an in-depth study of the courtship behavior, we show that females invariably open their cloaca (cloacal gaping) before engaging in pinwheel behavior, the circling movement that is the prelude to spermatophore uptake. In contrast, cloacal gaping was not observed in failed courtships, where females escaped or displayed thanatosis. Since gaping mainly occurred during male amplexus and cloacal imposition, which is the obvious period of pheromone transfer, we next investigated whether male courtship water (i.e., water holding courtship pheromones) alone was able to induce this reaction in females. These tests showed that courtship water induced cloacal gaping significantly more than water, even in the absence of a male. Cloacal gaping thus provides a simple and robust test for demonstrating courtship pheromone use in the Iberian ribbed newt. Since opening the cloaca is an essential prerequisite for spermatophore pick-up in all internally fertilizing salamanders, we hypothesize that variations on this assay will also be useful in several other species.

  1. Do female newts modify thermoregulatory behavior to manipulate egg size?

    PubMed

    Toufarová, Eliška; Gvoždík, Lumír

    2016-04-01

    Reproductive females manipulate offspring phenotypes by modifying conditions during embryogenesis. In ectotherms, the environmental control over embryogenesis is often realized by changes in maternal thermoregulation during gravidity. To determine if reproduction influences thermoregulatory behavior in species where females lay eggs shortly after fertilization (strict oviparity), we compared preferred body temperatures (Tp) between reproductive (egg-laying) and non-reproductive female newts, Ichthyosaura alpestris. Next, we exposed reproductive females to temperatures mimicking Tp ranges of reproductive and non-reproductive individuals to find out whether the maternally modified thermal regime influences ovum and jelly coat volume, and early cleavage rates at the time of oviposition. In the thermal gradient, reproductive females maintained their body temperatures within a narrower range than non-reproductive individuals. The exposure of ovipositing females to temperatures preferred during their reproductive and non-reproductive period had a negligible influence on egg size and early cleavage rates. We conclude that the modification of maternal thermoregulatory behavior provides a limited opportunity to manipulate egg traits in newts.

  2. Metacercariae of Clinostomum complanatum (Trematoda: Digenea) in European newts Triturus carnifex and Lissotriton vulgaris (Caudata: Salamandridae).

    PubMed

    Caffara, M; Bruni, G; Paoletti, C; Gustinelli, A; Fioravanti, M L

    2014-09-01

    Adults of Clinostomum spp. are digenetic trematodes found in fish-eating birds, reptiles and occasionally mammals, including humans. Freshwater snails serve as first intermediate hosts and many fish species and amphibians as second intermediate hosts. To date, amphibian hosts of Clinostomum metacercariae include members of urodele and anuran families in North America, but no data are available on infections of European amphibians, including newts. In this study, we characterize infections of Clinostomum complanatum metacercariae in four smooth (Lissotriton vulgaris) and 18 Italian crested newts (Triturus carnifex) from an artificial pond located in a protected area in Tuscany, Italy. Parasites were surgically removed from the infected newts and identified both morphologically and using sequences of a mitochondrial gene, cytochrome c oxidase I, and the ribosomal markers, internal transcribed spacers. This is the first record of C. complanatum in European newts and, more generally, in amphibians in Europe.

  3. Ranavirus-associated mass mortality in imported red tailed knobby newts (Tylototriton kweichowensis): a case report.

    PubMed

    Pasmans, Frank; Blahak, Silvia; Martel, An; Pantchev, Nikola; Zwart, Peer

    2008-05-01

    A mass die-off of imported red tailed knobby newts (Tylototriton kweichowensis) occurred in 2004 in Belgium and the Netherlands. In addition to massive infection with Rhabdias tokyoensis, Ranavirus was isolated from three dead newts examined virologically and the gene coding for the major capsid protein of the virus was sequenced. The isolate showed 99.8% similarity to the published sequence of frog virus 3. Upon experimental infection of axolotls (Ambystoma mexicanum) with this isolate, no marked pathology was noticed and the virus could not be re-isolated at 9weeks post-inoculation. Apart from the possibility of exposure of a non-sensitive host, the mortality episode in the newts may be related to stress resulting from the importation of the newts in breeding condition. This possibility is supported by the presence of degenerating egg-follicles in the females.

  4. Effects of temperature on muscle pHi and phosphate metabolites in newts and lungless salamanders.

    PubMed

    Johnson, D C; Burt, C T; Perng, W C; Hitzig, B M

    1993-11-01

    The effect of acute alterations in body temperature (BT) on intracellular pH (pHi) and phosphate metabolites was assessed in white skeletal muscle of intact newts and lungless red-backed salamanders using 31P-nuclear magnetic resonance spectroscopy. pHi decreased with increasing BT in the tail muscle of both newts and lungless red-backed salamanders. The change in pH with change in temperature from 10 to 30 degrees C was -0.018 U/degrees C in newts and -0.041 U/degrees C in red backs. The calculated alpha-imidazole for skeletal muscle cytosol did not change (0.56) in newts from 10 to 30 degrees C but fell from 0.69 to 0.43 in red-backed salamanders. Phosphocreatine (PCr)/Pi fell and Pi/beta-ATP rose with increasing temperature in both newts and red backs; however, the change was much greater in red backs. Providing the red backs with O2 at 30 degrees C led to higher pH and alpha-imidazole, comparable to that of newts, along with increased PCr/Pi and lower Pi/beta-ATP. Thus newts maintain white skeletal muscle cell cytosol alpha-imidazole constant with changes in BT, whereas red backs apparently do not. However, at the BT of preference, red backs and newts maintain similar muscle pHi and alpha-imidazole. The method of gas exchange appears to strongly influence the ability of an animal to maintain its acid-base status over a range of temperatures, and our results suggest that behavioral regulation of BT may involve alpha-imidazole regulation as well.

  5. Interactions of bullfrog tadpole predators and an insecticide: Predation release and facilitation

    USGS Publications Warehouse

    Boone, M.D.; Semlitsch, R.D.

    2003-01-01

    The effect of a contaminant on a community may not be easily predicted, given that complex changes in food resources and predator-prey dynamics may result. The objectives of our study were to determine the interactive effects of the insecticide carbaryl and predators on body size, development, survival, and activity of tadpoles of the bullfrog (Rana catesbeiana). We conducted the study in cattle tank mesocosm ponds exposed to 0, 3.5, or 7.0 mg/l carbaryl, and no predators or two red-spotted newts (Notophthalmus viridescens), bluegill sunfish (Lepomis macrochirus), or crayfish (Orconectes sp.). Carbaryl negatively affected predator survival by eliminating crayfish from all ponds, and by eliminating bluegill sunfish from ponds exposed to the highest concentration of carbaryl; carbaryl exposure did not effect survival of red-spotted newts. Because crayfish were eliminated by carbaryl, bullfrogs were released from predation and survival was near that of predator controls at low concentrations of carbaryl exposure. High concentrations of carbaryl reduced tadpole survival regardless of whether predators survived carbaryl exposure or not. Presence of crayfish and newts reduced tadpole survival, while bluegill sunfish appeared to facilitate bullfrog tadpole survival. Presence of carbaryl stimulated bullfrog tadpole mass and development. Our study demonstrates that the presence of a contaminant stress can alter community regulation by releasing prey from predators that are vulnerable to contaminants in some exposure scenarios.

  6. Temperature variability and moisture synergistically interact to exacerbate an epizootic disease.

    PubMed

    Raffel, Thomas R; Halstead, Neal T; McMahon, Taegan A; Davis, Andrew K; Rohr, Jason R

    2015-02-22

    Climate change is altering global patterns of precipitation and temperature variability, with implications for parasitic diseases of humans and wildlife. A recent study confirmed predictions that increased temperature variability could exacerbate disease, because of lags in host acclimation following temperature shifts. However, the generality of these host acclimation effects and the potential for them to interact with other factors have yet to be tested. Here, we report similar effects of host thermal acclimation (constant versus shifted temperatures) on chytridiomycosis in red-spotted newts (Notophthalmus viridescens). Batrachochytrium dendrobatidis (Bd) growth on newts was greater following a shift to a new temperature, relative to newts already acclimated to this temperature (15°C versus 25°C). However, these acclimation effects depended on soil moisture (10, 16 and 21% water) and were only observed at the highest moisture level, which induced greatly increased Bd growth and infection-induced mortality. Acclimation effects were also greater following a decrease rather than an increase in temperature. The results are consistent with previous findings that chytridiomycosis is associated with precipitation, lower temperatures and increased temperature variability. This study highlights host acclimation as a potentially general mediator of climate-disease interactions, and the need to account for context-dependencies when testing for acclimation effects on disease.

  7. Temperature variability and moisture synergistically interact to exacerbate an epizootic disease.

    PubMed

    Raffel, Thomas R; Halstead, Neal T; McMahon, Taegan A; Davis, Andrew K; Rohr, Jason R

    2015-02-22

    Climate change is altering global patterns of precipitation and temperature variability, with implications for parasitic diseases of humans and wildlife. A recent study confirmed predictions that increased temperature variability could exacerbate disease, because of lags in host acclimation following temperature shifts. However, the generality of these host acclimation effects and the potential for them to interact with other factors have yet to be tested. Here, we report similar effects of host thermal acclimation (constant versus shifted temperatures) on chytridiomycosis in red-spotted newts (Notophthalmus viridescens). Batrachochytrium dendrobatidis (Bd) growth on newts was greater following a shift to a new temperature, relative to newts already acclimated to this temperature (15°C versus 25°C). However, these acclimation effects depended on soil moisture (10, 16 and 21% water) and were only observed at the highest moisture level, which induced greatly increased Bd growth and infection-induced mortality. Acclimation effects were also greater following a decrease rather than an increase in temperature. The results are consistent with previous findings that chytridiomycosis is associated with precipitation, lower temperatures and increased temperature variability. This study highlights host acclimation as a potentially general mediator of climate-disease interactions, and the need to account for context-dependencies when testing for acclimation effects on disease. PMID:25567647

  8. Temperature variability and moisture synergistically interact to exacerbate an epizootic disease

    PubMed Central

    Raffel, Thomas R.; Halstead, Neal T.; McMahon, Taegan A.; Davis, Andrew K.; Rohr, Jason R.

    2015-01-01

    Climate change is altering global patterns of precipitation and temperature variability, with implications for parasitic diseases of humans and wildlife. A recent study confirmed predictions that increased temperature variability could exacerbate disease, because of lags in host acclimation following temperature shifts. However, the generality of these host acclimation effects and the potential for them to interact with other factors have yet to be tested. Here, we report similar effects of host thermal acclimation (constant versus shifted temperatures) on chytridiomycosis in red-spotted newts (Notophthalmus viridescens). Batrachochytrium dendrobatidis (Bd) growth on newts was greater following a shift to a new temperature, relative to newts already acclimated to this temperature (15°C versus 25°C). However, these acclimation effects depended on soil moisture (10, 16 and 21% water) and were only observed at the highest moisture level, which induced greatly increased Bd growth and infection-induced mortality. Acclimation effects were also greater following a decrease rather than an increase in temperature. The results are consistent with previous findings that chytridiomycosis is associated with precipitation, lower temperatures and increased temperature variability. This study highlights host acclimation as a potentially general mediator of climate–disease interactions, and the need to account for context-dependencies when testing for acclimation effects on disease. PMID:25567647

  9. A robust transcriptional program in newts undergoing multiple events of lens regeneration throughout their lifespan

    PubMed Central

    Sousounis, Konstantinos; Qi, Feng; Yadav, Manisha C; Millán, José Luis; Toyama, Fubito; Chiba, Chikafumi; Eguchi, Goro; Tsonis, Panagiotis A

    2015-01-01

    Newts have the ability to repeatedly regenerate their lens even during ageing. However, it is unclear whether this regeneration reflects an undisturbed genetic activity. To answer this question, we compared the transcriptomes of lenses, irises and tails from aged newts that had undergone lens regeneration 19 times with the equivalent tissues from young newts that had never experienced lens regeneration. Our analysis indicates that repeatedly regenerated lenses showed a robust transcriptional program comparable to young never-regenerated lenses. In contrast, the tail, which was never regenerated, showed gene expression signatures of ageing. Our analysis strongly suggests that, with respect to gene expression, the regenerated lenses have not deviated from a robust transcriptional program even after multiple events of regeneration throughout the life of the newt. In addition, our study provides a new paradigm in biology, and establishes the newt as a key model for the study of regeneration in relation to ageing. DOI: http://dx.doi.org/10.7554/eLife.09594.001 PMID:26523389

  10. Turning the fate of reprogramming cells from retinal disorder to regeneration by Pax6 in newts.

    PubMed

    Casco-Robles, Martin Miguel; Islam, Md Rafiqul; Inami, Wataru; Tanaka, Hibiki Vincent; Kunahong, Ailidana; Yasumuro, Hirofumi; Hanzawa, Shiori; Casco-Robles, Roman Martin; Toyama, Fubito; Maruo, Fumiaki; Chiba, Chikafumi

    2016-01-01

    The newt, a urodele amphibian, has an outstanding ability- even as an adult -to regenerate a functional retina through reprogramming and proliferation of the retinal pigment epithelium (RPE) cells, even though the neural retina is completely removed from the eye by surgery. It remains unknown how the newt invented such a superior mechanism. Here we show that disability of RPE cells to regenerate the retina brings about a symptom of proliferative vitreoretinopathy (PVR), even in the newt. When Pax6, a transcription factor that is re-expressed in reprogramming RPE cells, is knocked down in transgenic juvenile newts, these cells proliferate but eventually give rise to cell aggregates that uniformly express alpha smooth muscle actin, Vimentin and N-cadherin, the markers of myofibroblasts which are a major component of the sub-/epi-retinal membranes in PVR. Our current study demonstrates that Pax6 is an essential factor that directs the fate of reprogramming RPE cells toward the retinal regeneration. The newt may have evolved the ability of retinal regeneration by modifying a mechanism that underlies the RPE-mediated retinal disorders. PMID:27640672

  11. Turning the fate of reprogramming cells from retinal disorder to regeneration by Pax6 in newts

    PubMed Central

    Casco-Robles, Martin Miguel; Islam, Md Rafiqul; Inami, Wataru; Tanaka, Hibiki Vincent; Kunahong, Ailidana; Yasumuro, Hirofumi; Hanzawa, Shiori; Casco-Robles, Roman Martin; Toyama, Fubito; Maruo, Fumiaki; Chiba, Chikafumi

    2016-01-01

    The newt, a urodele amphibian, has an outstanding ability– even as an adult –to regenerate a functional retina through reprogramming and proliferation of the retinal pigment epithelium (RPE) cells, even though the neural retina is completely removed from the eye by surgery. It remains unknown how the newt invented such a superior mechanism. Here we show that disability of RPE cells to regenerate the retina brings about a symptom of proliferative vitreoretinopathy (PVR), even in the newt. When Pax6, a transcription factor that is re-expressed in reprogramming RPE cells, is knocked down in transgenic juvenile newts, these cells proliferate but eventually give rise to cell aggregates that uniformly express alpha smooth muscle actin, Vimentin and N-cadherin, the markers of myofibroblasts which are a major component of the sub-/epi-retinal membranes in PVR. Our current study demonstrates that Pax6 is an essential factor that directs the fate of reprogramming RPE cells toward the retinal regeneration. The newt may have evolved the ability of retinal regeneration by modifying a mechanism that underlies the RPE-mediated retinal disorders. PMID:27640672

  12. Turning the fate of reprogramming cells from retinal disorder to regeneration by Pax6 in newts.

    PubMed

    Casco-Robles, Martin Miguel; Islam, Md Rafiqul; Inami, Wataru; Tanaka, Hibiki Vincent; Kunahong, Ailidana; Yasumuro, Hirofumi; Hanzawa, Shiori; Casco-Robles, Roman Martin; Toyama, Fubito; Maruo, Fumiaki; Chiba, Chikafumi

    2016-09-19

    The newt, a urodele amphibian, has an outstanding ability- even as an adult -to regenerate a functional retina through reprogramming and proliferation of the retinal pigment epithelium (RPE) cells, even though the neural retina is completely removed from the eye by surgery. It remains unknown how the newt invented such a superior mechanism. Here we show that disability of RPE cells to regenerate the retina brings about a symptom of proliferative vitreoretinopathy (PVR), even in the newt. When Pax6, a transcription factor that is re-expressed in reprogramming RPE cells, is knocked down in transgenic juvenile newts, these cells proliferate but eventually give rise to cell aggregates that uniformly express alpha smooth muscle actin, Vimentin and N-cadherin, the markers of myofibroblasts which are a major component of the sub-/epi-retinal membranes in PVR. Our current study demonstrates that Pax6 is an essential factor that directs the fate of reprogramming RPE cells toward the retinal regeneration. The newt may have evolved the ability of retinal regeneration by modifying a mechanism that underlies the RPE-mediated retinal disorders.

  13. Assessing cardiomyocyte proliferative capacity in the newt heart and primary culture.

    PubMed

    Simon, Hans-Georg; Odelberg, Shannon

    2015-01-01

    Unlike humans, adult newts possess extraordinary abilities to functionally regenerate lost and injured organs, including cardiac muscle. The most remarkable feature of mature newt cardiomyocytes is their ability to reenter the cell cycle, undergo cell division, and serve as a reservoir for progenitor cells. There are, however, a number of unsolved questions concerning the cellular and molecular mechanisms that underlie this plasticity; for example, we still lack a deeper understanding of the cell-inherent properties of newt cardiomyocytes and to what degree they differ from their mammalian counterparts. Along with considerable morphological changes at the wound site, a striking feature shared by different regenerating tissues in the newt is an extensive and dynamic remodeling of the extracellular environment. The dynamic signaling between cardiomyocytes and extracellular environment is of eminent importance in the control of the differentiated state of the cell, but the molecular details remain elusive. In this chapter, we describe methods to assess cardiomyocyte proliferation in vivo and enrich primary cardiomyocytes from newt hearts to study their behavior, taking extracellular matrix components into consideration.

  14. Morphing of the phylogeographic lineages of the Balkan alpine newts (Ichthyosaura alpestris, Caudata, Salamandridae): in situ morphological diversification.

    PubMed

    Vukov, Tanja D; Sotiropoulos, Konstantinos; Kalezić, Miloš L; Džukić, Georg

    2011-12-01

    Numerous alpine newt (Ichthyosaura alpestris) populations from the Balkans, representing all the previously established phylogeographic lineages, were studied for variations in various morphological characteristics (body size and shape, skull qualitative traits and number of trunk vertebrae). Here, we present a decoupling of morphological and mtDNA phylogeographic substructuring in the alpine newt on the Balkan Peninsula. In sharp contrast to other European newts (Triturus spp., Lissotriton spp.), the vast majority of morphological variation in the alpine newt is concentrated at the population level indicating an in situ morphological diversification. We found that the rate of morphological change is similar to the rate of mtDNA change. We hypothesize that the alpine newts are characterized by non-adaptive morphological evolution.

  15. Phenotypic flexibility of gape anatomy fine-tunes the aquatic prey-capture system of newts.

    PubMed

    Van Wassenbergh, Sam; Heiss, Egon

    2016-01-01

    A unique example of phenotypic flexibility of the oral apparatus is present in newts (Salamandridae) that seasonally change between an aquatic and a terrestrial habitat. Newts grow flaps of skin between their upper and lower jaws, the labial lobes, to partly close the corners of the mouth when they adopt an aquatic lifestyle during their breeding season. Using hydrodynamic simulations based on μCT-scans and cranial kinematics during prey-capture in the smooth newt (Lissotriton vulgaris), we showed that this phenotypic flexibility is an adaptive solution to improve aquatic feeding performance: both suction distance and suction force increase by approximately 15% due to the labial lobes. As the subsequent freeing of the corners of the mouth by resorption of the labial lobes is assumed beneficial for the terrestrial capture of prey by the tongue, this flexibility of the mouth fine-tunes the process of capturing prey throughout the seasonal switching between water and land. PMID:27383663

  16. Cyclic Guanidine Compounds from Toxic Newts Support the Hypothesis that Tetrodotoxin is Derived from a Monoterpene.

    PubMed

    Kudo, Yuta; Yasumoto, Takeshi; Mebs, Dietrich; Cho, Yuko; Konoki, Keiichi; Yotsu-Yamashita, Mari

    2016-07-18

    The biosynthesis of tetrodotoxin (TTX), a potent neurotoxin consisting of a 2,4-dioxaadamantane skeleton and a guanidine moiety, is an unsolved problem in natural product chemistry. Recently, the first C5-C10 directly bonded TTX analogue, 4,9-anhydro-10-hemiketal-5-deoxyTTX, was obtained from toxic newts and its carbon skeleton suggested a possible monoterpene origin. On the basis of this hypothesis, screening of predicted biosynthetic intermediates of TTX was performed using two MS-guided methods. Herein, five novel cyclic guanidine compounds from toxic newts are reported which commonly contain a cis-fused bicyclic structure including a six-membered cyclic guanidine. These structures could be biosynthetically derived from geranyl guanidine through oxidation, cyclization, and/or isomerization steps. LC-MS analysis confirmed the widespread distribution of the five novel compounds in toxic newt species. These results support the hypothesis that TTX is derived from a monoterpene. PMID:27248052

  17. Phenotypic flexibility of gape anatomy fine-tunes the aquatic prey-capture system of newts.

    PubMed

    Van Wassenbergh, Sam; Heiss, Egon

    2016-07-07

    A unique example of phenotypic flexibility of the oral apparatus is present in newts (Salamandridae) that seasonally change between an aquatic and a terrestrial habitat. Newts grow flaps of skin between their upper and lower jaws, the labial lobes, to partly close the corners of the mouth when they adopt an aquatic lifestyle during their breeding season. Using hydrodynamic simulations based on μCT-scans and cranial kinematics during prey-capture in the smooth newt (Lissotriton vulgaris), we showed that this phenotypic flexibility is an adaptive solution to improve aquatic feeding performance: both suction distance and suction force increase by approximately 15% due to the labial lobes. As the subsequent freeing of the corners of the mouth by resorption of the labial lobes is assumed beneficial for the terrestrial capture of prey by the tongue, this flexibility of the mouth fine-tunes the process of capturing prey throughout the seasonal switching between water and land.

  18. Aquatic-to-terrestrial habitat shift reduces energy expenditure in newts.

    PubMed

    Kristín, Peter; Gvoždík, Lumír

    2014-04-01

    Many organisms seasonally modify their standard metabolic rates (SMR). However, the diversity of cues triggering the acclimatization response remains little understood. We examined the influence of experimentally induced aquatic-to-terrestrial habitat shift on the thermal sensitivity of SMR in newts. Standard metabolic rates increased with temperature (13-23°C), although consistently lower in terrestrial than aquatic individuals. Motor activity during respirometry trials decreased with temperature at similar rates in both groups. We conclude that in newts, a habitat shift might represent an important modulator of the seasonal acclimatization response in SMR. Lowered SMR suggests the potential to reduce newt maintenance costs and depletion of caloric reserves during the activity-limited period on land.

  19. A comparative analysis of predator-induced plasticity in larval Triturus newts.

    PubMed

    Schmidt, B R; Van Buskirk, J

    2005-03-01

    Species that occupy similar habitats are expected to show convergent phenotypes. If habitats are defined by the presence of predators, then traits that modify vulnerability to predation, including predator-induced phenotypic plasticity, should be similar within habitats. We tested this idea using larvae of six syntopic newt species belonging to the two Triturus clades. Behavioural plasticity induced by odonate predators was strongly dissimilar between the two main clades but similar within them. Morphological plasticity was variable among species, even between one pair of closely related species. A predation experiment tested whether differences between clades could be caused by differences in body size. Size-specific vulnerability differed between newts in the small-bodied and large-bodied clades, indicating that similar predators may affect the two clades differently. The results showed both similarity and dissimilarity in predator-induced phenotypic plasticity in syntopic larval newts although theory suggests that divergence is unlikely in such ecologically similar species.

  20. Phenotypic flexibility of gape anatomy fine-tunes the aquatic prey-capture system of newts

    NASA Astrophysics Data System (ADS)

    van Wassenbergh, Sam; Heiss, Egon

    2016-07-01

    A unique example of phenotypic flexibility of the oral apparatus is present in newts (Salamandridae) that seasonally change between an aquatic and a terrestrial habitat. Newts grow flaps of skin between their upper and lower jaws, the labial lobes, to partly close the corners of the mouth when they adopt an aquatic lifestyle during their breeding season. Using hydrodynamic simulations based on μCT-scans and cranial kinematics during prey-capture in the smooth newt (Lissotriton vulgaris), we showed that this phenotypic flexibility is an adaptive solution to improve aquatic feeding performance: both suction distance and suction force increase by approximately 15% due to the labial lobes. As the subsequent freeing of the corners of the mouth by resorption of the labial lobes is assumed beneficial for the terrestrial capture of prey by the tongue, this flexibility of the mouth fine-tunes the process of capturing prey throughout the seasonal switching between water and land.

  1. Phenotypic flexibility of gape anatomy fine-tunes the aquatic prey-capture system of newts

    PubMed Central

    Van Wassenbergh, Sam; Heiss, Egon

    2016-01-01

    A unique example of phenotypic flexibility of the oral apparatus is present in newts (Salamandridae) that seasonally change between an aquatic and a terrestrial habitat. Newts grow flaps of skin between their upper and lower jaws, the labial lobes, to partly close the corners of the mouth when they adopt an aquatic lifestyle during their breeding season. Using hydrodynamic simulations based on μCT-scans and cranial kinematics during prey-capture in the smooth newt (Lissotriton vulgaris), we showed that this phenotypic flexibility is an adaptive solution to improve aquatic feeding performance: both suction distance and suction force increase by approximately 15% due to the labial lobes. As the subsequent freeing of the corners of the mouth by resorption of the labial lobes is assumed beneficial for the terrestrial capture of prey by the tongue, this flexibility of the mouth fine-tunes the process of capturing prey throughout the seasonal switching between water and land. PMID:27383663

  2. Cyclic Guanidine Compounds from Toxic Newts Support the Hypothesis that Tetrodotoxin is Derived from a Monoterpene.

    PubMed

    Kudo, Yuta; Yasumoto, Takeshi; Mebs, Dietrich; Cho, Yuko; Konoki, Keiichi; Yotsu-Yamashita, Mari

    2016-07-18

    The biosynthesis of tetrodotoxin (TTX), a potent neurotoxin consisting of a 2,4-dioxaadamantane skeleton and a guanidine moiety, is an unsolved problem in natural product chemistry. Recently, the first C5-C10 directly bonded TTX analogue, 4,9-anhydro-10-hemiketal-5-deoxyTTX, was obtained from toxic newts and its carbon skeleton suggested a possible monoterpene origin. On the basis of this hypothesis, screening of predicted biosynthetic intermediates of TTX was performed using two MS-guided methods. Herein, five novel cyclic guanidine compounds from toxic newts are reported which commonly contain a cis-fused bicyclic structure including a six-membered cyclic guanidine. These structures could be biosynthetically derived from geranyl guanidine through oxidation, cyclization, and/or isomerization steps. LC-MS analysis confirmed the widespread distribution of the five novel compounds in toxic newt species. These results support the hypothesis that TTX is derived from a monoterpene.

  3. Is reproductive effort environmentally or energetically controlled? The case of the Danube crested newt (Triturus dobrogicus).

    PubMed

    Cogălniceanu, Dan; Buhaciuc, Elena; Tudor, Marian; Rosioru, Daniela

    2013-11-01

    Reproductive strategies have evolved from a series of trade-offs between cost and timing of reproduction. We tested whether the reproductive effort of female Danube crested newts, Triturus dobrogicus, was environmentally or energetically constrained. We collected females migrating towards the water and kept them separately, with males. Deposited eggs were collected daily during the experiment. More eggs were deposited by older females and by females starting to reproduce earlier. Batches of eggs from females depositing more eggs had a lower hatching success, suggesting decreased viability. Oviposition lasted on average 22.7 days. Female newts showed no loss of weight during this period. At the end of the egg deposition period we injected a subset of females with hormones that triggered the deposition of additional eggs. This suggests that egg deposition in Danube crested newts is environmentally constrained, as females stopped oviposition despite having mature eggs in their ovaries.

  4. Abnormal limb regeneration in adult newts exposed to the fungicide Maneb 80. A histological study.

    PubMed

    Zavanella, T; Zaffaroni, N P; Arias, E

    1984-01-01

    The effects of the fungicide Maneb 80 (manganese ethylenebisdithiocarbamate, 80% active ingredient) on the regenerating limb of the adult crested newt, Triturus cristatus carnifex, was studied. Female newts were exposed percutaneously to 5 ppm Maneb 80. One group of control newts was exposed to the inert ingredients of Maneb 80 (sodium lignin sulfonate and n-butylnaphthalene sulfonate), and another control group was kept in tap water. The limbs were examined histologically at weekly intervals throughout the regeneration period and at the end of the experiment (10-12 wk postamputation). The regenerating limbs of all the animals exposed to Maneb 80 showed growth retardation and skeletal abnormalities. Histological examination provided evidence that vascular disturbances are important for the genesis of the developmental abnormalities induced by Maneb 80. The inert ingredients had a promoting effect on limb growth and had no teratogenic effects under our experimental conditions. There were no histological differences between the two control groups.

  5. Visualization of newt aragonitic otoconial matrices using transmission electron microscopy

    NASA Technical Reports Server (NTRS)

    Steyger, P. S.; Wiederhold, M. L.

    1995-01-01

    Otoconia are calcified protein matrices within the gravity-sensing organs of the vertebrate vestibular system. These protein matrices are thought to originate from the supporting or hair cells in the macula during development. Previous studies of mammalian calcitic, barrel-shaped otoconia revealed an organized protein matrix consisting of a thin peripheral layer, a well-defined organic core and a flocculent matrix inbetween. No studies have reported the microscopic organization of the aragonitic otoconial matrix, despite its protein characterization. Pote et al. (1993b) used densitometric methods and inferred that prismatic (aragonitic) otoconia have a peripheral protein distribution, compared to that described for the barrel-shaped, calcitic otoconia of birds, mammals, and the amphibian utricle. By using tannic acid as a negative stain, we observed three kinds of organic matrices in preparations of fixed, decalcified saccular otoconia from the adult newt: (1) fusiform shapes with a homogenous electron-dense matrix; (2) singular and multiple strands of matrix; and (3) more significantly, prismatic shapes outlined by a peripheral organic matrix. These prismatic shapes remain following removal of the gelatinous matrix, revealing an internal array of organic matter. We conclude that prismatic otoconia have a largely peripheral otoconial matrix, as inferred by densitometry.

  6. Changes in the numbers of osteoclasts in newts under conditions of microgravity

    NASA Astrophysics Data System (ADS)

    Berezovska, O. P.; Rodionova, N. V.; Grigoryan, E. N.; Mitashov, V. I.

    Intensity of osteoclastic resorption and calcium content were investigated in intact limb bones of the newts flown on board of a biosatellite Cosmos-2229 after amputation of their forelimbs and tail. Using X-ray microanalysis it was shown an increase in calcium content in the bones on 20^th day after operation. Histological study revealed an activation of osteoclastic resorption on endosteal surface of long bones. The newts exposed after surgery on a biosatellite had the same level of bone mineralisation as operated ground control ones, but the increase in number of polynuclear osteoclasts was lower.

  7. Experimental evidence for a cost of resistance to the fungal pathogen, Batrachochytrium dendrobatidis, for the palmate newt, Lissotriton helveticus

    PubMed Central

    2013-01-01

    Background Batrachochytrium dendrobatidis (Bd), the causative agent of chytridiomycosis, is decimating amphibians worldwide. Unsurprisingly, the majority of studies have therefore concentrated on documenting morbidity and mortality of susceptible species and projecting population consequences as a consequence of this emerging infectious disease. Currently, there is a paucity of studies investigating the sub-lethal costs of Bd in apparently asymptomatic species, particularly in controlled experimental conditions. Here we report the consequences of a single dose of B. dendrobatidis zoospores on captive adult palmate newts (Lissotriton helveticus) for morphological and behavioural traits that associate with reproductive success. Results A single exposure to ~2000 zoospores induced a subclinical Bd infection. One week after inoculation 84% of newts tested positive for Bd, and of those, 98% had apparently lost the infection by the day 30. However, exposed newts suffered significant mass loss compared with control newts, and those experimental newts removing higher levels of Bd lost most mass. We found no evidence to suggest that three secondary sexual characteristics (areas of dorsal crest and rear foot webbing, and length of tail filament) were reduced between experimental versus control newts; in fact, rear foot webbing was 26% more expansive at the end of the experiment in exposed newts. Finally, compared with unexposed controls, exposure to Bd was associated with a 50% earlier initiation of the non-reproductive terrestrial phase. Conclusions Our results suggest that Bd has measureable, but sub-lethal effects, on adult palmate newts, at least under the laboratory conditions presented. We conclude that the effects reported are most likely to be mediated through the initiation of costly immune responses and/or tissue repair mechanisms. Although we found no evidence of hastened secondary sexual trait regression, through reducing individual body condition and potentially

  8. Comparison of the morphology of the inner ear between newts and frogs in relation to their locomotory capability.

    PubMed

    Harada, Yasuo; Kasuga, Sigeo; Tamura, Souichiro

    2002-05-01

    The ultrastructural differences between the inner ears of Japanese red-bellied newts (Cynops pyrrhogaster) and black-spotted pond frogs (Rana nigromaculata) were investigated. Scanning electron microscopic observations showed apparent morphological differences in the shape of the ampulla cristae and the localization of the striola in the saccular macula. There were differences in the length of the kinocilia of the sensory hairs in each sensory region. In addition, the diameters of the bundles of stereocilia differed between the two species: the bundles of stereocilia in the semicircular cristae were thicker in frogs than in newts, while those of the utricular and lagenal maculae were thicker in newts than in frogs.

  9. Love is blind: indiscriminate female mating responses to male courtship pheromones in newts (Salamandridae).

    PubMed

    Treer, Dag; Van Bocxlaer, Ines; Matthijs, Severine; Du Four, Dimitri; Janssenswillen, Sunita; Willaert, Bert; Bossuyt, Franky

    2013-01-01

    Internal fertilization without copulation or prolonged physical contact is a rare reproductive mode among vertebrates. In many newts (Salamandridae), the male deposits a spermatophore on the substrate in the water, which the female subsequently takes up with her cloaca. Because such an insemination requires intense coordination of both sexes, male newts have evolved a courtship display, essentially consisting of sending pheromones under water by tail-fanning towards their potential partner. Behavioral experiments until now mostly focused on an attractant function, i.e. showing that olfactory cues are able to bring both sexes together. However, since males start their display only after an initial contact phase, courtship pheromones are expected to have an alternative function. Here we developed a series of intraspecific and interspecific two-female experiments with alpine newt (Ichthyosaura alpestris) and palmate newt (Lissotriton helveticus) females, comparing behavior in male courtship water and control water. We show that male olfactory cues emitted during tail-fanning are pheromones that can induce all typical features of natural female mating behavior. Interestingly, females exposed to male pheromones of their own species show indiscriminate mating responses to conspecific and heterospecific females, indicating that visual cues are subordinate to olfactory cues during courtship.

  10. Behavioral rhythms of the Japanese newts, Cynops pyrrhogaster, under a semi-natural condition

    NASA Astrophysics Data System (ADS)

    Nagai, Kiyoko; Oishi, T.

    Locomotor activity rhythms of the Japanese newt, Cynops pyrrhogaster, were recorded under a semi-natural condition using phototransistor systems. The daily activity rhythm showed a seasonal change: the locomotor activity was mainly diurnal (active during the daytime) from spring to early summer; mainly nocturnal (active during the night-time) from summer to autumn; and showed either a diurnal or nocturnal pattern, depending on the ambient temperature, in winter. To analyze the daily activity in detail, we observed the behavior of a group of newts (three males, three females) throughout 24 h. Four types of behavior (respiration, feeding, mating, and resting on the land) were observed. Each behavior had daily rhythms and showed a seasonal change. The behavior on land showed mainly a nocturnal or bimodal pattern (activity rhythms with two peaks) throughout the year and was more frequently observed in summer. Mating behavior also showed a seasonal change: high activity in spring, with peaks in the early morning and evening, but no activity in summer. Except in winter, feeding and respiratory behavior showed no seasonal changes in either activity period or frequency. Coupling between behavior and the clock seems to be weak in the Japanese newt because of indistinct daily rhythms and frequent phase changes of locomotor activity in water. Physical factors such as humidity and temperature seem to affect strongly the daily activity of the newts.

  11. Development of the gravity-sensing organs in the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Wiederhold, Michael L.; Yamashita, Masamichi; Asashima, Makoto

    1992-01-01

    Pre-mated adult female newts and fertilized eggs will be flown on the International Microgravity Laboratory-2 flight, schedule for 1994. One objective of the flight will be to observe the influence of microgravity on the development of the gravity-sensing organs in the inner ear. These organs contain sensory hair cells covered by a layer of dense stones (otoliths). Gravity and linear acceleration exert forces on these masses, leading to excitation of the nerve fibers innervating the hair cells. If the production of the otoliths is regulated to reach an optimal weight, their development would be abnormal in microgravity. Ground-based control experiments are reported describing the developmental sequence in which the otoliths and their associated sensory epithelium appear and increase in size. Three-dimensional reconstruction of serial sections through the otic vesicle of newt embryos at stages 31 through 40 demonstrate the first appearance, relative position and growth of the otoliths. In adult newts, the otoconia in the utricle appear similar to mammalian otoconia, which are composed of calcite. The newt saccular otoconia are at least 99% aragonite, as is found in most aquatic species. Reports of experiments in which fertilized frog eggs were flown on a Russian Cosmos mission conclude that the utricular otolith is increased in volume, whereas the saccular otolith maintains normal size, suggesting that at least the utricular weight might be regulated.

  12. Two distal-less related homeobox-containing genes expressed in regeneration blastemas of the newt.

    PubMed

    Beauchemin, M; Savard, P

    1992-11-01

    Urodeles, like the newt, are able to replace their limbs and tail following amputation by the formation of a blastema, a mass of proliferating mesenchymal cells originating from the tissue adjacent to the cut surface. As this capacity may involve genetic control, we investigated in adult tissues the expression of genes controlling embryonic development. We screened a newt cDNA library with a redundant oligonucleotide specific to the highly conserved third helix of the DNA-binding domain of homeobox genes. Five classes of cDNA have been isolated. We report the nucleotide sequence and the tissue distribution of two of them, NvHBox-4 and NvHBox-5. The amino acid sequences of both homeodomains are highly homologous (83 and 87% identity) to distal-less, a Drosophila homeobox gene expressed during the development of appendages. NvHBox-4 and NvHBox-5 express respectively 2.8 and 2 kb transcripts. The pattern of expression of both genes is identical in adult tissues of the newt. Polyadenylated transcripts are detectable in the forelimbs, hindlimbs, the tail, flank, and brain as well as in limb and tail blastemas. Analysis of dissected tissue from the hindlimbs indicated that the expression of both genes is restricted to the skin. This work is a first step toward understanding the possible relation between sustained expression of homeobox-containing genes in adult newt tissues and regeneration potential.

  13. Analysis of the hematopoietic tissue in Pleurodeles waltl newts exposed to 2 g hypergravity

    NASA Astrophysics Data System (ADS)

    Domaratskaya, Elena; Nikonova, Tatyana M.; Grigoryan, Eleonora N.; Dvorochkin, Natalya; Yousuf, Rukhsana; Almeida, Eduardo; Butorina, Nina N.

    2012-07-01

    Gravity is an important factor in creating biologically-relevant mechanical loads, and in spaceflight living organisms encounter both microgravity as well as hypergravity conditions. Here we studied the influence of hypergravity on the hematopoietic tissue of P. waltl newts in parallel with tissue regeneration experiments of the newt lens and tail. At day 9 post-surgery one group of newts was subjected to centrifugation at 2 g (2G, 12 days), while another was kept at 1 g. In addition, a basal control in wet mats, at 1g, (BC, 1G), and an aquarium control, neutrally buoyant, (AC, low G), were also performed. Differential blood counts and histological analysis of the spleen and liver were carried out in experimental and control groups of animals. At day 21 post-surgery in all groups (AC, 1G, and 2G), the number of neutrophils in the blood was significantly lower than in BC indicating a decrease in the inflammation induced by surgery. The 2G group however, showed numbers of neutrophils significantly higher than AC (neutrally buoyant) animals. This result suggests that post-operative inflammation can persist longer at 2 g that under unloaded aquarium conditions. In contrast we did not observe any significant differences in lymphocyte numbers between any experimental and control groups. Histological examination of the liver and spleen also did not show any significant morphological alterations due to hypergravity. These results indicate that 12 day exposure to hypergravity at 2 g, had only partial influence on newt hematopoiesis, possibly extending the duration of surgery-related inflammatory responses. Data obtained with newts in our previous experiments on Foton-M2 and Foton-M3 flights in microgravity also showed only slight effect on blood cells. Furthermore microgravity also did not cause any morphological changes in the hematopoietic and lymphoid tissues, and did not impair the proliferative capacity of newt hematopoietic cells. In sum these results indicate the

  14. Interactions of Amphibians, Fish, and Macroinvertebrates in a Southeastern Wetland

    NASA Astrophysics Data System (ADS)

    Schultheis, R. D.; Batzer, D. P.

    2005-05-01

    In fishless habitats, amphibians often compete with and are predators of macroinvertebrates. Unlike fish, the effects these interactions have on macroinvertebrate communities have been largely unexplored. We conducted an experiment in a semi-permanent oxbow wetland in the Piedmont region of Georgia to explore interactions between amphibians and macroinvertebrates. The predator community was dominated by Ambystoma opacum (Marbled Salamander) and Notophthalmus viridescens (Eastern Newt). Salamanders and newts were excluded from areas of wetland habitat using wire mesh cages (1.5M x 1.5M, 3mm mesh). The macroinvertebrate communities within the cages were then compared to the ambient habitat outside the cages. Fish, mostly Lepomis macrochirus (Bluegill) and Gambusia affinis (Mosquito Fish), colonized the wetland late in the first year of the study, and became common by year two. Also in year two, Rana catesbeiana (Bullfrog) became established. Thus, we were able to explore the variable effects on the macroinvertebrate community of a changing predator complex over a two year period.

  15. Biochemical and mechanical environment cooperatively regulate skeletal muscle regeneration

    PubMed Central

    Calve, Sarah; Simon, Hans-Georg

    2012-01-01

    During forelimb regeneration in the newt Notophthalmus viridescens, the dynamic expression of a transitional matrix rich in hyaluronic acid, tenascin-C, and fibronectin controls muscle cell behavior in vivo and in vitro. However, the influence of extracellular matrix (ECM) remodeling on tissue stiffness and the cellular response to mechanical variations during regeneration was unknown. By measuring the transverse stiffness of tissues in situ, we found undifferentiated regenerative blastemas were less stiff than differentiated stump muscle (13.3±1.6 vs. 16.6±1.2 kPa). To directly determine how ECM and stiffness combine to affect skeletal muscle fragmentation, migration, and fusion, we coated silicone-based substrates ranging from 2 to 100 kPa with matrices representative of transitional (tenascin-C and fibronectin) and differentiated environments (laminin and Matrigel). Using live-cell imaging, we found softer tenascin-C-coated substrates significantly enhanced migration and fragmentation of primary newt muscle cells. In contrast, stiffer substrates coated with laminin, Matrigel, or fibronectin increased differentiation while suppressing migration and fragmentation. These data support our in vivo observations that a transitional matrix of reduced stiffness regulates muscle plasticity and progenitor cell recruitment into the regenerative blastema. These new findings will enable the determination of how biochemical and mechanical cues from the ECM control genetic pathways that drive regeneration.—Calve, S., Simon, H.-G. Biochemical and mechanical environment cooperatively regulate skeletal muscle regeneration. PMID:22415307

  16. Metamorphosis inhibition: an alternative rearing protocol for the newt, Cynops pyrrhogaster.

    PubMed

    Chiba, Chikafumi; Yamada, Shouta; Tanaka, Hibiki; Inae-Chiba, Maiko; Miura, Tomoya; Casco-Robles, Martin Miguel; Yoshikawa, Taro; Inami, Wataru; Mizuno, Aki; Islam, Md Rafiqul; Han, Wenje; Yasumuro, Hirofumi; Matsumoto, Mikiko; Takayanagi, Miyako

    2012-05-01

    The newt is an indispensable model animal, of particular utility for regeneration studies. Recently, a high-throughput transgenic protocol was established for the Japanese common newt, Cynops pyrrhogaster. For studies of regeneration, metamorphosed animals may be favorable; however, for this species, there is no efficient protocol for maintaining juveniles after metamorphosis in the laboratory. In these animals, survival drops drastically after metamorphosis as their foraging behaviour changes to adapt to a terrestrial habitat, making feeding in the laboratory with live or moving foods more difficult. To elevate the efficiency of laboratory rearing of this species, we examined metamorphosis inhibition (Ml) protocols to bypass the period (four months to two years after hatching) in which the animal feeds exclusively on moving foods. We found that approximately 30% of animals survived after 2-year Ml, and that the survivors continuously grew, only with static food while maintaining their larval form and foraging behaviour in 0.02% thiourea (TU) aqueous solution, then metamorphosed when returned to a standard rearing solution even after 2-year-MI. The morphology and foraging behavior (feeding on static foods in water) of these metamorphosed newts resembled that of normally developed adult newts. Furthermore, they were able to fully regenerate amputated limbs, suggesting regenerative capacity is preserved in these animals. Thus, controlling metamorphosis with TU allows newts to be reared with the same static food under aqueous conditions, providing an alternative rearing protocol that offers the advantage of bypassing the critical period and obtaining animals that have grown sufficiently for use in regeneration studies.

  17. Position dependent expression of a homeobox gene transcript in relation to amphibian limb regeneration.

    PubMed Central

    Savard, P; Gates, P B; Brockes, J P

    1988-01-01

    Adult urodele amphibians such as the newt Notophthalmus viridescens are capable of regenerating their limbs and tail by formation of a blastema, a growth zone of mesenchymal progenitor cells. In an attempt to identify genes implicated in specification of the regenerate, we screened a newt forelimb blastema cDNA library with homeobox probes, and isolated and sequenced clones that identify a 1.8 kb polyadenylated transcript containing a homeobox. The transcript is derived from a single gene called NvHbox 1, the newt homologue of XIHbox 1 (Xenopus), HHO.c8 (human) and Hox-6.1 (mouse). The cDNA for the 1.8 kb transcript has two exons as determined by isolation and partial sequencing of a genomic clone. The expression of the transcript shows several interesting features in relation to limb regeneration: (i) Hybridization of Northern blots of poly(A)+ RNA from limb and tail and their respective blastemas shows that the transcript in limb tissues has exons 1 and 2, whereas a 1.8 kb transcript in tail tissues has only exon 2. (ii) The transcript is expressed in limbs of adult newt but not of adult Xenopus, raising the possibility that this contributes to an explanation of the loss of regenerative ability with maturation in adult anurans. (iii) The transcript is expressed at a higher level in a proximal (mid-humerus) blastema than in a distal one (mid-radius). When distal blastemas were proximalized by treatment with retinoic acid, no change in the level of the transcript was detected by Northern analysis at a single time point after amputation.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2907476

  18. Intra-specific variability of hindlimb length in the palmate newt: an indicator of population isolation induced by habitat fragmentation?

    PubMed

    Trochet, Audrey; Le Chevalier, Hugo; Baillat, Boris; Barthe, Laurent; Pottier, Gilles; Calvez, Olivier; Ribéron, Alexandre; Blanchet, Simon

    2016-04-01

    Habitat fragmentation is one of the main drivers of global amphibian decline. Anthropogenic landscape elements can act as barriers, hindering the dispersal that is essential for maintaining gene flow between populations. Dispersal ability can be influenced by locomotor performance, which in turn can depend on morphological traits, such as hindlimb length (HLL) in amphibians. Here, we tested relationships between HLL and environmental variables--road types, forests and agricultural lands--among 35 sub-populations of palmate newts (Lissotriton helveticus) in southwestern France. We expected roads to select for short-legged newts due to a higher mortality of more mobile individuals (long-legged newts) when crossing roads. Accordingly, short-legged newts were found in the vicinity of roads, whereas long-legged newts were found closer to forests and in ponds close geographically to another water body. HLL in newts was hence influenced by habitat types in a heterogeneous landscape, and could therefore be used as an indicator of population isolation in a meta-population system. PMID:27122009

  19. A novel RNA-binding protein from Triturus carnifex identified by RNA-ligand screening with the newt hammerhead ribozyme

    PubMed Central

    Denti, Michela A.; Alba, A. Emilio Martínez de; Sägesser, Rudolf; Tsagris, Mina; Tabler, Martin

    2000-01-01

    The newt hammerhead ribozyme is transcribed from Satellite 2 DNA, which consists of tandemly repeated units of 330 bp. However, different transcripts are synthesized in different tissues. In all somatic tissues and in testes, dimeric and multimeric RNA transcripts are generated which, to some extent, self-cleave into monomers at the hammerhead domain. In ovaries, primarily a distinct monomeric unit is formed by transcription, which retains an intact hammerhead self-cleavage site. The ovarian monomeric RNA associates to form a 12S complex with proteins that are poorly characterised so far. In this work we identified NORA, a protein that binds the ovarian form of the newt ribozyme. We show that the newt ribozyme binds to the Escherichia coli-expressed protein, as well as to a protein of identical size that is found exclusively in newt ovaries. Also NORA mRNA was detectable only in ovary, but in neither somatic tissues nor testes. The tissue-specific expression of NORA is analogous to the ovary-specific transcription of the newt ribozyme. Although NORA was identified by its ability to bind to the newt ribozyme in the presence of a vast excess of carrier RNA, it was able to interact with certain other RNA probes. This novel RNA-binding protein does not contain any motif characteristic for RNA-binding proteins or any other known protein domain, but it shares a striking similarity with a rat resiniferatoxin-binding protein. PMID:10666442

  20. Integrative phylogeography of Calotriton newts (Amphibia, Salamandridae), with special remarks on the conservation of the endangered Montseny brook newt (Calotriton arnoldi).

    PubMed

    Valbuena-Ureña, Emilio; Amat, Fèlix; Carranza, Salvador

    2013-01-01

    The genus Calotriton includes two species of newts highly adapted to live in cold and fast-flowing mountain springs. The Pyrenean brook newt (Calotriton asper), restricted to the Pyrenean region, and the Montseny brook newt (Calotriton arnoldi), endemic to the Montseny massif and one of the most endangered amphibian species in Europe. In the present manuscript, we use an integrative approach including species distribution modeling (SDM), molecular analyses of mitochondrial and nuclear DNA sequence data and morphology to unravel the historical processes that have contributed to shaping the biogeography and genetic structure of the genus Calotriton, with special emphasis on the conservation of C. arnoldi. The results of the molecular analyses confirm that, despite having originated recently, being ecologically similar and geographically very close, there is no signal of hybridization between C. asper and C. arnoldi. SDM results suggest that tough environmental conditions on mountains tops during glacial periods, together with subsequent warmer periods could have prevented the contact between the two species. Within the critically endangered C. arnoldi, a high genetic structure is revealed despite its extremely small distribution range compared to C. asper. Haplotype networks, AMOVA and SAMOVA analyses suggest that two distinct groups of populations can be clearly differentiated with absence of gene flow. This is in concordance with morphological differentiation and correlates with its geographical distribution, as the two groups are situated on the eastern and western sides of a river valley that acts as a barrier. The genetic and morphological results are highly important for the ongoing conservation program of C. arnoldi and strongly justify the management of this species into at least two independent evolutionary significant units (eastern and western sectors) to guarantee the long-term population viability.

  1. Integrative Phylogeography of Calotriton Newts (Amphibia, Salamandridae), with Special Remarks on the Conservation of the Endangered Montseny Brook Newt (Calotriton arnoldi)

    PubMed Central

    Valbuena-Ureña, Emilio; Amat, Fèlix; Carranza, Salvador

    2013-01-01

    The genus Calotriton includes two species of newts highly adapted to live in cold and fast-flowing mountain springs. The Pyrenean brook newt (Calotriton asper), restricted to the Pyrenean region, and the Montseny brook newt (Calotriton arnoldi), endemic to the Montseny massif and one of the most endangered amphibian species in Europe. In the present manuscript, we use an integrative approach including species distribution modeling (SDM), molecular analyses of mitochondrial and nuclear DNA sequence data and morphology to unravel the historical processes that have contributed to shaping the biogeography and genetic structure of the genus Calotriton, with special emphasis on the conservation of C. arnoldi. The results of the molecular analyses confirm that, despite having originated recently, being ecologically similar and geographically very close, there is no signal of hybridization between C. asper and C. arnoldi. SDM results suggest that tough environmental conditions on mountains tops during glacial periods, together with subsequent warmer periods could have prevented the contact between the two species. Within the critically endangered C. arnoldi, a high genetic structure is revealed despite its extremely small distribution range compared to C. asper. Haplotype networks, AMOVA and SAMOVA analyses suggest that two distinct groups of populations can be clearly differentiated with absence of gene flow. This is in concordance with morphological differentiation and correlates with its geographical distribution, as the two groups are situated on the eastern and western sides of a river valley that acts as a barrier. The genetic and morphological results are highly important for the ongoing conservation program of C. arnoldi and strongly justify the management of this species into at least two independent evolutionary significant units (eastern and western sectors) to guarantee the long-term population viability. PMID:23750201

  2. Changes in brain gangliosides of the neotene and metamorphic (thyroxine-induced) newt axolotl (Ambystoma mexicanum).

    PubMed

    Hilbig, R; Schmitt, M; Rahmann, H

    1987-01-01

    Qualitative and quantitative changes in the concentration of proteins, sialoglycoproteins and gangliosides and in the composition of gangliosides in the brains of the neotene and the thyroxine-induced metamorphic newt axolotl (Ambystoma mexicanum) were investigated. During metamorphosis two polar gangliosides (GT1b and GQ1b) decreased by about 5% each. On the contrary GD1a increased to 10%. Another developmental trend was a slight increase of two other disialogangliosides (GD1b, GD2). Additionally, incorporation profiles (2-8 days) of 14C-N-Ac-mannosamine, the specific precursor for gangliosides, in the brain of neotene and metamorphic axolotls were followed giving evidence of significant changes in the sialoglycoconjugate metabolism of the central nervous system during metamorphosis of this newt.

  3. Parallelization in SCALE continuous-energy resonance module GEMINEWTRN and transport module NEWT

    SciTech Connect

    Zhong, Z.; Downar, T. J.; DeHart, M. D.; Williams, M. L.

    2006-07-01

    A new resonance module, GEMINEWTRN, has been developed in SCALE, it can calculate the continuous-energy neutron flux within the whole two-dimensional geometry, providing us a rigorous solution. However, the new code needs tremendously amount of computation and memory for practical problem. To relieve the computational burden and memory requirement, parallelization has been implemented into GEMINEWTRN, both angular and spatial decomposition have been adopted so that both the computation and the memory requirement on each processor can be saved considerably, and this effort makes the new resonance method much feasible for practical use. Because the two-dimensional geometry capability and SN/ESC solver of GEMINEWTRN come from lattice physics code NEWT, the similar parallel technique has also been implemented into NEWT, which can also save the computation considerably. (authors)

  4. Regenerative capacity in newts is not altered by repeated regeneration and ageing.

    PubMed

    Eguchi, Goro; Eguchi, Yukiko; Nakamura, Kenta; Yadav, Manisha C; Millán, José Luis; Tsonis, Panagiotis A

    2011-07-12

    The extent to which adult newts retain regenerative capability remains one of the greatest unanswered questions in the regeneration field. Here we report a long-term lens regeneration project spanning 16 years that was undertaken to address this question. Over that time, the lens was removed 18 times from the same animals, and by the time of the last tissue collection, specimens were at least 30 years old. Regenerated lens tissues number 18 and number 17, from the last and the second to the last extraction, respectively, were analysed structurally and in terms of gene expression. Both exhibited structural properties identical to lenses from younger animals that had never experienced lens regeneration. Expression of mRNAs encoding key lens structural proteins or transcription factors was very similar to that of controls. Thus, contrary to the belief that regeneration becomes less efficient with time or repetition, repeated regeneration, even at old age, does not alter newt regenerative capacity.

  5. Resource partitioning in two heterochronic populations of Greek Alpine newts, Triturus alpestris veluchiensis

    NASA Astrophysics Data System (ADS)

    Denoël, Mathieu; Schabetsberger, Robert

    2003-04-01

    Current ecological models suggest that the maintenance of trophic polymorphisms is favoured by a different resource use in alternative morphs. Facultative paedomorphosis in newts is an example of phenotypic variation as paedomorphs retain morphological larval traits, such as gills and gill slits. The aim of this study was to find out whether heterochronic morphs occupy particular micro-habitats and focus on specific prey items. Resource partitioning was found between morphs. It concerns mainly food selection with paedomorphs preying more on plankton and less on terrestrial invertebrates than metamorphs. Some habitat specializations were also found with metamorphs being more abundant at the water surface than paedomorphs. Diel variation in habitat use of the two different morphs was minimal. Polymorphism allows Alpine newts to exploit the different resources in the lakes in order to minimize intraspecific competition, but the extent of resource partitioning depends on habitat characteristics.

  6. Tetrodotoxin levels in larval and metamorphosed newts (Taricha granulosa) and palatability to predatory dragonflies.

    PubMed

    Gall, Brian G; Stokes, Amber N; French, Susannah S; Schlepphorst, Elizabeth A; Brodie, Edmund D; Brodie, Edmund D

    2011-06-01

    Some populations of the newt Taricha granulosa possess extremely high concentrations of the neurotoxin tetrodotoxin (TTX). Tetrodotoxin is present in adult newts and their eggs, but has been assumed to be absent from the larval stage. We tested larval and metamorphosed juveniles for the presence of TTX and evaluated the palatability of these developmental stages to predatory dragonfly nymphs. All developmental stages retained substantial quantities of TTX and almost all individuals were unpalatable to dragonfly nymphs. Tetrodotoxin quantity varied greatly among individuals. When adjusted for mass, TTX concentrations declined steadily through metamorphosis. Several juveniles were palatable to dragonflies and these individuals had significantly lower TTX levels than unpalatable juveniles. These results suggest that despite previous assumptions, substantial quantities of TTX, originally deposited in the embryo, are retained by the developing larvae and metamorphosed juveniles and this quantity is enough to make them unpalatable to some potential predators.

  7. Ultrastructural observations on blood vessels surrounding normal and regenerating spinal cord in newt.

    PubMed

    Lorenzo, A

    1992-01-01

    The ultrastructural analysis of capillaries surrounding normal and regenerating caudal spinal cords of two species of newt (Triturus vulgaris and T. cristatus) is reported. Around normal spinal cords, capillaries were generally continuous. Surrounding the regenerating spinal cords the various capillaries of the regenerating blastema appeared discontinuous with small or broad gaps along the capillary wall. This was seen even after two months of tail regeneration when the spinal cord was similar to the normal and many axons were myelinating. These morphological findings suggest that during tail regeneration in newts the blood-brain barrier is not very effective. Also extravasating mature and immature blood cells were observed inside regenerating capillaries. Therefore growing capillaries can exchange metabolites and, possibly, growth factors with the nervous tissue and the other regenerating tissues.

  8. Impermeability of newt cerebral and pial capillaries to exogenous peroxidase. A light and electron microscope study.

    PubMed

    Ciani, F; Del Grande, P; Franceschini, V; Caniato, G; Minelli, G

    1983-01-01

    The permeability of cerebral vessels to exogenous peroxidase was studied in the newt. The reaction product was found only inside the cerebral or pial blood vessels. Electron microscope investigations revealed the presence of reaction product along the luminal area of vessels and in some parts of the intercellular spaces at the level of tight junctions joining endothelial cells. On the basis of the ultrastructural peroxidase localization, the presence of a brain-blood barrier in Triturus is discussed.

  9. Morphogenetic changes occurring in the regenerating newt tail under changed gravity conditions

    NASA Astrophysics Data System (ADS)

    Radugina, Elena A.; Grigoryan, Eleonora N.; Dvorochkin, Natasha; Almeida, Eduardo

    2012-07-01

    It is widely accepted that gravity greatly affects animal physiology, development, and alters gene expression. Recently it became apparent that it can also affect tissue morphogenesis. In our work, we developed special laboratory conditions that allow us to produce the gravity-dependent alterations in tail regenerates of the newt Pleurodeles waltl. We examined the dynamic morphogenetic changes during 50-day tail regeneration using computer morphometric analysis. Changes that we observed under these conditions were comparable with those found earlier in our spaceflight experiments. The newts kept in aquarium deep water (low g) after 1/3 tail amputation developed normal lanceolate regenerates. In contrast, the animals that stayed on the moist mat (1g) developed tail regenerates curved ventrally, with tips almost touching the mat. The similar results were obtained with a 12-day centrifugation at 2g. The study of the regenerate morphology in low g, 1g, and 2g animal groups allowed us to determine the stage at which the morphological changes in regenerates become apparent, and to detect the main morphological events associated with the development of tail curve, such as bending of ependymal tube and reorientation of the forming cartilage. We describe cellular processes foregoing observed tissue morphogenetic changes, such as cell migration, condensation in cell population, and unequal proliferation in different areas of epidermis and blastema. Cell proliferation in epidermis and blastema of tails regenerated under the conditions of different gravitational load was evaluated by BrdU assay. In 1g newts, cell proliferation increased within the dorso-apical region of the regenerates compared with that in low g group. These results provide us with a valuable insight into the regenerative tissue homostasis that involves cell division, cell death, and migration in the newt regenerating tail. In addition, these findings could provide us with better understanding of the

  10. Similar Local and Landscape Processes Affect Both a Common and a Rare Newt Species

    PubMed Central

    Denoël, Mathieu; Perez, Amélie; Cornet, Yves; Ficetola, Gentile Francesco

    2013-01-01

    Although rare species are often the focus of conservation measures, more common species may experience similar decline and suffer from the same threatening processes. We tested this hypothesis by examining, through an information-theoretic approach, the importance of ecological processes at multiple scales in the great crested newt Triturus cristatus, regionally endangered and protected in Europe, and the more common smooth newt, Lissotriton vulgaris. Both species were similarly affected by the same processes, i.e. suitability of aquatic and terrestrial components of their habitat at different scales, connectivity among breeding sites, and the presence of introduced fish. T. cristatus depended more on water depth and aquatic vegetation than L. vulgaris. The results show that environmental pressures threaten both common and rare species, and therefore the more widespread species should not be neglected in conservation programs. Because environmental trends are leading to a deterioration of aquatic and terrestrial habitat features required by newt populations, populations of the common species may follow the fate of the rarest species. This could have substantial conservation implications because of the numerical importance of common species in ecosystems and because commonness could be a transient state moving towards rarity. On the other hand, in agreement with the umbrella species concept, targeting conservation efforts on the most demanding species would also protect part of the populations of the most common species. PMID:23658765

  11. Can newts cope with the heat? Disparate thermoregulatory strategies of two sympatric species in water.

    PubMed

    Balogová, Monika; Gvoždík, Lumír

    2015-01-01

    Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms. PMID:25993482

  12. Can Newts Cope with the Heat? Disparate Thermoregulatory Strategies of Two Sympatric Species in Water

    PubMed Central

    Balogová, Monika; Gvoždík, Lumír

    2015-01-01

    Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms. PMID:25993482

  13. C5-C10 directly bonded tetrodotoxin analogues: possible biosynthetic precursors of tetrodotoxin from newts.

    PubMed

    Kudo, Yuta; Yamashita, Yoko; Mebs, Dietrich; Cho, Yuko; Konoki, Keiichi; Yasumoto, Takeshi; Yotsu-Yamashita, Mari

    2014-12-22

    The identification of novel tetrodotoxin (TTX, 1) analogues would significantly contribute to the elucidation of its biosynthetic pathway. In this study, the first C5-C10 directly bonded TTX analogues, 4,9-anhydro-10-hemiketal-5-deoxyTTX (2) and 4,9-anhydro-8-epi-10-hemiketal-5,6,11-trideoxyTTX (3), were found in the newt Cynops ensicauda popei by using a screening method involving HILIC-LC-MS/MS focused on the fragment ions of TTX analogues, and their structures were elucidated by spectroscopic methods. Compound 2 was detected in a wide range of newt species, and the 2 and TTX contents of 22 newt specimens were correlated (rs =0.88). Based on these results and its structural features, 2 was predicted to serve as a precursor of TTX that would be directly converted into 4,9-anhydroTTX (4) by Baeyer-Villiger-like oxidation or via 4,9-anhydro-5-deoxyTTX formed by cleavage of the C5-C10 bond. The bicyclic carbon skeletons of 2 and 3 suggested a possible monoterpene origin for TTX.

  14. Arginine: A Potent Prey Attractant to Predatory Newts in Mountain Streams

    NASA Astrophysics Data System (ADS)

    Ferrer, R. P.; Zimmer, R. K.

    2005-05-01

    Chemoreception of aquatic organisms has been well-studied in the laboratory, but rarely in the field. The California newt, Taricha torosa, in natural stream habitats is an excellent animal for exploring behavioral responses to prey odors. Here, we selected 13 amino acids for field bioassays based on their concentrations in prey tissue extracts. Bioassays were calibrated for stimulus dilution by means of fluorescent dye releases and flow-through spectrofluorometry. Moreover, hydrodynamic properties of stream flows were determined using an electromagnetic current meter. Of all amino acids tested, only arginine, alanine and glycine were significantly attractive (relative to stream water controls). These three substances caused free-ranging newts to turn upstream and swim towards the odor sources. Additional experiments showed that arginine was the most effective attractant, evoking plume-tracking behavior at concentrations as low as 10 nM. In subsequent trials, nine arginine analogs were tested, but each compound failed to elicit a significant response. Even subtle changes to arginine, such as the addition of a single carbon to the side chain, destroyed all bioactivity. Within its natural habitat, the California newt thus exhibits keen sensitivity and narrow tuning to the free amino acid, arginine, a chemical signal of its prey.

  15. Cloacal anatomy of the male Carpathian newt, Lissotriton montandoni (Amphibia, Salamandridae), in the breeding season.

    PubMed

    Osikowski, Artur; Cierniak-Zuzia, Karolina

    2013-09-01

    This study presents the first light microscopy-based description of the cloacal anatomy of male Carpathian newts (Lissotriton montandoni). This European newt species hybridizes with its sister species, the smooth newt (L. vulgaris), despite a high level of prezygotic isolation. The goal of the study was to ascertain possible anatomical differences in cloacal anatomy, especially pheromone and spermatophore producing glands, which might potentially affect reproductive isolation between L. montandoni and L. vulgaris. The cloaca of L. montandoni males consists of the cloacal tube, cloacal chamber, pseudopenis, and aggregations of cloacal glands. Four main types of cloacal glands were recognized. Pheromone-producing dorsal glands are of two types due to differences in their secretory epithelium: cuboidal and high prismatic. The remaining glands: ventral, pelvic, and Kingsbury's glands, are most likely involved in the synthesis of spermatophore components. Two distinct groups of ventral glands were identified: posterior and anterior ventral glands. In comparison with L. vulgaris, no evident differences were found that could potentially affect courtship pheromone synthesis by dorsal glands or the base and the cap of the spermatophore produced by the remaining cloacal glands.

  16. Can newts cope with the heat? Disparate thermoregulatory strategies of two sympatric species in water.

    PubMed

    Balogová, Monika; Gvoždík, Lumír

    2015-01-01

    Many ectotherms effectively reduce their exposure to low or high environmental temperatures using behavioral thermoregulation. In terrestrial ectotherms, thermoregulatory strategies range from accurate thermoregulation to thermoconformity according to the costs and limits of thermoregulation, while in aquatic taxa the quantification of behavioral thermoregulation have received limited attention. We examined thermoregulation in two sympatric newt species, Ichthyosaura alpestris and Lissotriton vulgaris, exposed to elevated water temperatures under semi-natural conditions. According to a recent theory, we predicted that species for which elevated water temperatures pose a lower thermal quality habitat, would thermoregulate more effectively than species in thermally benign conditions. In the laboratory thermal gradient, L. vulgaris maintained higher body temperatures than I. alpestris. Semi-natural thermal conditions provided better thermal quality of habitat for L. vulgaris than for I. alpestris. Thermoregulatory indices indicated that I. alpestris actively thermoregulated its body temperature, whereas L. vulgaris remained passive to the thermal heterogeneity of aquatic environment. In the face of elevated water temperatures, sympatric newt species employed disparate thermoregulatory strategies according to the species-specific quality of the thermal habitat. Both strategies reduced newt exposure to suboptimal water temperatures with the same accuracy but with or without the costs of thermoregulation. The quantification of behavioral thermoregulation proves to be an important conceptual and methodological tool for thermal ecology studies not only in terrestrial but also in aquatic ectotherms.

  17. Female newts (Taricha granulosa) produce tetrodotoxin laden eggs after long term captivity.

    PubMed

    Gall, Brian G; Stokes, Amber N; French, Susannah S; Brodie, Edmund D; Brodie, Edmund D

    2012-11-01

    We investigated the presence of tetrodotoxin (TTX) in the eggs of wild-caught newts (Taricha granulosa) at capture and again after one, two, and three years in captivity. Females initially produced eggs that contained quantities of TTX similar to previous descriptions of eggs from wild-caught adults. After the first year in captivity, the egg toxicity from each female declined, ultimately remaining constant during each of the successive years in captivity. Despite declining, all females continued to produce eggs containing substantial quantities of TTX during captivity. The decline in toxicity can not be attributed to declining egg mass but may be the result of the abbreviated reproductive cycle to which the captive newts were subjected in the lab. Finally, an estimate of the amount of TTX provisioned in the entire clutch from each female is similar to the quantity of TTX regenerated in the skin after electrical stimulation. These results, coupled with other long-term studies on the maintenance and regeneration of TTX in the skin, suggests an endogenous origin of TTX in newts.

  18. Sperm transport after insemination in the Alpine newt (Triturus alpestris, Caudata, Salamandridae).

    PubMed

    Osikowski, Artur

    2007-01-01

    The goal of this study was to test if sperm transport to the spermathecae in the Alpine newt (Triturus alpestris) requires active co-operation of the female. Artificial insemination of anaesthetised female newts was conducted using spermatophores collected from courting males and with sperm duct contents collected from sacrificed males. Sperm was present in the spermathecae of 9 out of 10 females inseminated with the spermatophores but in only 1 out of 8 females inseminated with sperm duct contents. The females of both groups laid some eggs after insemination, and a portion of these eggs in group of females inseminated with spermatophores were fertilized. However, the number of eggs produced by the females was much lower than typical egg-production in newts. The presence of sperm in the spermathecae of females inseminated with spermatophores and lack of sperm in the spermathecae of females inseminated with sperm duct contents suggests that sperm transport is either induced by the substances present in spermatophores and/or that sperm from the sperm duct is not fully mobile in comparison with sperm from the spermatophores.

  19. Ultrastructural study and cholinesterase activity of paired capillaries in the newt brain.

    PubMed

    Ciani, F; Franceschini, V

    1984-01-01

    We have investigated the ultrastructural and histochemical (AChE and BuChE) features of intracerebral vessels in newt. The blood vessels of the newt brain are paired and end in a closed loop. The two limbs, each of them has delineate the lumen by one endothelial cell, are enclosed within a single basement membrane and are separated from each other by a thin intercapillary wall. The brain capillaries are un-fenestrated and the overlapping endothelial cells were connected by clefts. Ependymal astrocytes extensively ensheath the surface of brain capillaries, but the sheats are incomplete. Pericytes and mast cells are frequently sandwiched in the endothelial basal lamina. Microglial cells are also present adjacent to cerebral vessels. The newt cerebral capillaries are characterized by high levels of AChE. This enzyme is localized in the basal membrane and in extracellular spaces between the overlapping endothelial cells. The vascular walls are instead deprived of BuChE activity. The non-nervous role of cholinesterases is discussed.

  20. Rapid corticosterone-induced impairment of amplectic clasping occurs in the spinal cord of roughskin newts (taricha granulosa).

    PubMed

    Lewis, Christine M; Rose, James D

    2003-01-01

    Courtship clasping, a reproductive behavior in male roughskin newts (Taricha granulosa), is rapidly blocked by an action of corticosterone (CORT) at a specific neuronal membrane receptor. The CORT-induced impairment of clasping in behaving newts appears to be mediated partly by an elimination of clasping-related activity in medullary reticulospinal neurons. Previous studies of rapid CORT actions in Taricha have focused on the brain, so existence of CORT action in the spinal cord or peripheral nervous system has not been assessed. The present study used newts with a high cervical spinal transection to examine potential spinal or peripheral CORT effects on clasping by the hindlimbs in response to pressure on the cloaca. Spinal transection causes clasps elicited by cloacal stimulation to be very sustained beyond the termination of the eliciting stimulus. In spinally transected newts, CORT caused a dose-dependent depression in the duration as well as quality of the clasp that appeared within 10 min of injection. CORT selectively impaired the usual sustained maintenance of a clasp after termination of cloacal stimulation, but not clasp elicitation during stimulation. These effects were not produced by dexamethasone, a synthetic glucocorticoid that binds poorly to the CORT membrane receptor. The CORT effect on clasp maintenance but not clasp elicitation implies selective action on an intraspinal generator for clasping but not on sensory or efferent neuromuscular aspects of the response. These results indicate the presence in the newt spinal cord of the CORT membrane receptor that exerts functional effects distinctly different from those on the brainstem.

  1. [Competence factors of retinal pigment epithelium cells for reprogramming in the neuronal direction during retinal regeneration in newts].

    PubMed

    Grigorian, E N

    2015-01-01

    Retinal pigment epithelium (RPE) cells that have the unique ability to reprogram retinal cells @in vivo@ were analyzed in the adult newt. Our own data and that available in the literature on the peculiarities of the biology of these cells (from morphology to molecular profile, which can be associated with the capability of phenotype change) were summarized: It was established that the molecular traits of specialized and poorly differentiated cells are combined in RPE of the adult newt. It was registered that persistent (at a low level) proliferation and rapid change of specific cytoskeleton proteins can contribute to the success of RPE cell reprogramming in the neuronal direction. Each of the considered factors of competence for reprogramming can be found for animal RPE, whose cells are not able @in vivo@ to change the phenotype to a neuronal one; however, their totality (supported by the epigenetic state permissive for conversion) is probably an internal property of only newt RPE. PMID:25872395

  2. Effects of temperature on embryonic and early larval growth and development in the rough-skinned newt (Taricha granulosa).

    PubMed

    Smith, Geoffrey D; Hopkins, Gareth R; Mohammadi, Shabnam; M Skinner, Heather; Hansen, Tyler; Brodie, Edmund D; French, Susannah S

    2015-07-01

    We investigated the effects of temperature on the growth and development of embryonic and early larval stages of a western North American amphibian, the rough-skinned newt (Taricha granulosa). We assigned newt eggs to different temperatures (7, 14, or 21°C); after hatching, we re-assigned the newt larvae into the three different temperatures. Over the course of three to four weeks, we measured total length and developmental stage of the larvae. Our results indicated a strong positive relationship over time between temperature and both length and developmental stage. Importantly, individuals assigned to cooler embryonic temperatures did not achieve the larval sizes of individuals from the warmer embryonic treatments, regardless of larval temperature. Our investigation of growth and development at different temperatures demonstrates carry-over effects and provides a more comprehensive understanding of how organisms respond to temperature changes during early development. PMID:25965021

  3. Development of the otolith organs and semicircular canals in the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Yamashita, M.; Larsen, K. A.; Batten, J. S.; Koike, H.; Asashima, M.

    1995-01-01

    The sequence in which the otoliths and semicircular canals and their associated sensory epithelia appear and develop in the newt are described. Three-dimensional reconstruction of serial sections through the otic vesicle of newt embryos from stages 31 through 58 demonstrate the first appearance, relative position and growth of the otoliths. A single otolith is first seen in stage 33 embryos (approximately 9 days old); this splits into separate utricular and saccular otoliths at stage 40 (13 days). The lateral semicircular canal is the first to appear, at stage 41 (14 days). The anterior and posterior canals appear approximately one week later and the vestibular apparatus is essentially fully formed at stage 58 (approximately 5 weeks). The data reported here will serve as ground-based controls for fertilized newt eggs flown on the International Microgravity Laboratory-2 Space Shuttle flight, to investigate the influence of microgravity on the development of the gravity-sensing organs.

  4. [Competence factors of retinal pigment epithelium cells for reprogramming in the neuronal direction during retinal regeneration in newts].

    PubMed

    Grigorian, E N

    2015-01-01

    Retinal pigment epithelium (RPE) cells that have the unique ability to reprogram retinal cells @in vivo@ were analyzed in the adult newt. Our own data and that available in the literature on the peculiarities of the biology of these cells (from morphology to molecular profile, which can be associated with the capability of phenotype change) were summarized: It was established that the molecular traits of specialized and poorly differentiated cells are combined in RPE of the adult newt. It was registered that persistent (at a low level) proliferation and rapid change of specific cytoskeleton proteins can contribute to the success of RPE cell reprogramming in the neuronal direction. Each of the considered factors of competence for reprogramming can be found for animal RPE, whose cells are not able @in vivo@ to change the phenotype to a neuronal one; however, their totality (supported by the epigenetic state permissive for conversion) is probably an internal property of only newt RPE.

  5. Effects of temperature on embryonic and early larval growth and development in the rough-skinned newt (Taricha granulosa).

    PubMed

    Smith, Geoffrey D; Hopkins, Gareth R; Mohammadi, Shabnam; M Skinner, Heather; Hansen, Tyler; Brodie, Edmund D; French, Susannah S

    2015-07-01

    We investigated the effects of temperature on the growth and development of embryonic and early larval stages of a western North American amphibian, the rough-skinned newt (Taricha granulosa). We assigned newt eggs to different temperatures (7, 14, or 21°C); after hatching, we re-assigned the newt larvae into the three different temperatures. Over the course of three to four weeks, we measured total length and developmental stage of the larvae. Our results indicated a strong positive relationship over time between temperature and both length and developmental stage. Importantly, individuals assigned to cooler embryonic temperatures did not achieve the larval sizes of individuals from the warmer embryonic treatments, regardless of larval temperature. Our investigation of growth and development at different temperatures demonstrates carry-over effects and provides a more comprehensive understanding of how organisms respond to temperature changes during early development.

  6. Non-invasive assessment of otolith formation during development of the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Koike, H.; Nakamura, K.; Nishimura, K.; Kashima, I.; Wiederhold, M. L.; Asashima, M.

    1995-01-01

    Pre-mated adult female newts and embryos have been flown on the International Microgravity Laboratory-2 (IML-2) Space Shuttle flight in 1994 (Wiederhold et al., 1992b). With the specimens available from this flight, the calcification of otoliths, ulna, radius and backbone of the flown larvae and adult newts were analyzed. The experiments presented here studied the development of the otoliths on the ground. Otoliths of living newts, from embryo to adult, were observed in situ with the application of a new X-ray and bio-imaging analyzer system. For the establishment of this method, newts at different developmental stages were used. An imaging plate temporarily stores the X-ray energy pattern at the bio-imaging analyzer. A latent image on the imaging plate was transformed into a digital time series signal with an image reader. Acquired digital information was computed with the image processor. The processed information was recorded on film with an image recorder, in order to visualize it on an enlargement computed radiograph. To analyze development of the otoliths, photo-stimulated luminescence level was detected by an image analyzer, using transmitted X-ray photons. A single clump of otoconia could first be seen at stage 33. Stage-36 embryos first have distinguishable otoliths, with the utricle in front and saccule behind. Our results show that this X-ray method detects the otoliths equally as well as sectioning. In the newt, the mandibular/maxillary bone formed before the spine. It is suspected that for the newt embryo, living in water, feeding becomes necessary prior to support of the body.

  7. Spatial and temporal instability of local biotic community mediate a form of aposematic defense in newts, consisting of carotenoid-based coloration and tetrodotoxin.

    PubMed

    Mochida, Koji; Kitada, Minoru; Ikeda, Koichi; Toda, Mamoru; Takatani, Tomohiro; Arakawa, Osamu

    2013-09-01

    Most animals advertise their unprofitability to potential predators via conspicuous signals. Whether the strength of this aposematic signal indicates the quality and quantity of chemical defenses in animals is controversial. Here, we investigated the relationship between the conspicuousness of an aposematic signal and toxicity, which likely depends, at least in part, on dietary sources, in the newt Cynops pyrrhogaster. Our results indicate that the magnitude of the aposematic signal was not correlated with the amount of tetrodotoxin (TTX) and 6-epi TTX of wild individuals among populations. Using atoxic newts, reared from eggs, we compared the ability to accumulate TTX from diets between mainland and island populations. Newts of a mainland population that exhibited a less conspicuous signal accumulated more TTX than did equivalent newts of an insular population that displayed a more conspicuous signal; this was unrelated to variation in the toxicity of wild individuals of these two populations. We also found toxicity of wild newts changed over approximately one generation (10 years) in both populations. These results indirectly suggest that environmental variance, such as fluctuations in TTX resources in nature, may obscure differences in the ability of wild newts to accumulate TTX, and that this variation may be responsible for a lack of correlation between the strength of a newt's signal and its toxicity in the wild. These results imply that toxicity of wild individuals likely is a phenotypic trait largely dependent on environmental conditions. PMID:24014098

  8. Spatial and temporal instability of local biotic community mediate a form of aposematic defense in newts, consisting of carotenoid-based coloration and tetrodotoxin.

    PubMed

    Mochida, Koji; Kitada, Minoru; Ikeda, Koichi; Toda, Mamoru; Takatani, Tomohiro; Arakawa, Osamu

    2013-09-01

    Most animals advertise their unprofitability to potential predators via conspicuous signals. Whether the strength of this aposematic signal indicates the quality and quantity of chemical defenses in animals is controversial. Here, we investigated the relationship between the conspicuousness of an aposematic signal and toxicity, which likely depends, at least in part, on dietary sources, in the newt Cynops pyrrhogaster. Our results indicate that the magnitude of the aposematic signal was not correlated with the amount of tetrodotoxin (TTX) and 6-epi TTX of wild individuals among populations. Using atoxic newts, reared from eggs, we compared the ability to accumulate TTX from diets between mainland and island populations. Newts of a mainland population that exhibited a less conspicuous signal accumulated more TTX than did equivalent newts of an insular population that displayed a more conspicuous signal; this was unrelated to variation in the toxicity of wild individuals of these two populations. We also found toxicity of wild newts changed over approximately one generation (10 years) in both populations. These results indirectly suggest that environmental variance, such as fluctuations in TTX resources in nature, may obscure differences in the ability of wild newts to accumulate TTX, and that this variation may be responsible for a lack of correlation between the strength of a newt's signal and its toxicity in the wild. These results imply that toxicity of wild individuals likely is a phenotypic trait largely dependent on environmental conditions.

  9. Tetrodotoxin and its analogue 6-epitetrodotoxin in newts (Triturus spp.; Urodela, Salamandridae) from southern Germany.

    PubMed

    Yotsu-Yamashita, Mari; Mebs, Dietrich; Kwet, Axel; Schneider, Michael

    2007-08-01

    Tetrodotoxin (TTX) and its analogue 6-epitetrodotoxin (6-epiTTX) were quantitatively assayed in 59 newts representing four Triturus species (Triturus alpestris, Triturus cristatus, Triturus helveticus, Triturus vulgaris) from southern Germany by a post-column fluorescent-HPLC system. Both toxins were detected in only 15 specimens of the four species. The toxins levels varied considerably among individuals (TTX: 0.11-9.0microg/g; 6-epiTTX: 0.05-17.0microg/g). 6-epiTTX was found to be the major component.

  10. Dermocystid infection and associated skin lesions in free-living palmate newts (Lissotriton helveticus) from Southern France.

    PubMed

    González-Hernández, Milagros; Denoël, Mathieu; Duffus, Amanda J L; Garner, Trenton W J; Cunningham, Andrew A; Acevedo-Whitehouse, Karina

    2010-09-01

    Since the early 1900s, mesomycetozoan parasites have been reported in both European anuran and caudate species. These reports have primarily been descriptive, which has made assessing the impact of these parasites on host populations difficult. Anecdotal reports of dermocystidium-like parasites are becoming widespread across Europe, possibly indicating that these mesomycetozoan parasites are increasing in distribution and/or abundance. This highlights the need for further investigations into the occurrence, pathogenesis and effects on host health of these parasitic infections for free-living amphibian populations, particularly those which are already stressed or threatened by other factors. Here we report the results of pathological, microbiological and molecular investigations used to characterize unidentified skin lesions in palmate newts (Lissotriton helveticus) from Larzac, France. We confirm that the lesions are the result of infection with a novel dermocystidium-like parasite, which is related to Amphybiocystidium ranae. We also show that the same parasite is distributed across several newt breeding sites. The lesions that result from infection with this parasite range from single or few vesicular or nodular cutaneous lesions to multiple coalescing skin ulcers with extensive hemorrhages. The latter have not been previously described in amphibians due to mesomycetozoan parasitic infection. Dermocystid DNA was detected only in newts that showed lesions, providing comparative evidence of the parasite's pathogenicity. We discuss the potential significance of the presence of this pathogen in the context of the population health of palmate newts.

  11. iTRAQ-based proteomic analysis of adaptive response in the regenerating limb of the Cynops orientalis newt.

    PubMed

    Geng, Xiao-Fang; Guo, Jian-Lin; Zang, Xia-Yan; Sun, Jing-Yan; Li, Peng-Fei; Zhang, Fu-Chun; Xu, Cun-Shuan

    2015-01-01

    The newt has the powerful capacity to regenerate lost limbs following amputation, and represents an excellent model organism to study regenerative processes. However, the molecular basis of the adaptive response in the regenerating limb of the Chinese fire-bellied newt Cynops orientalis immediately after amputation remains unclear. To better understand the adaptive response immediately after limb amputation at the protein level, we used isobaric tags for relative and absolute quantitation (iTRAQ) coupled with LC-MS/MS methods to analyze changes in the proteome of the regenerating newt limb that occurred 2 h and 8 h after amputation. We identified 152 proteins with more than 1.5-fold change in expression compared to control. GO annotation analysis classified these proteins into several categories such as signaling, Ca(2+) binding and translocation, transcription and translation, immune response, cell death, cytoskeleton, metabolism, etc. Further ingenuity pathway analysis (IPA) showed that several signaling pathways were significantly changed at 2 h and 8 h after amputation, including EIF2 signaling, acute phase response signaling, tight junction signaling and calcium signaling, suggesting these pathways may be closely related to the adaptive response immediately after limb amputation. This work provides novel insights into understanding the molecular processes related to newt limb regeneration immediately after amputation, and a basis for further study of regenerative medicine. PMID:26864489

  12. A Phenotypic Point of View of the Adaptive Radiation of Crested Newts (Triturus cristatus Superspecies, Caudata, Amphibia).

    PubMed

    Ivanović, Ana; Džukić, Georg; Kalezić, Miloš

    2012-01-01

    The divergence in phenotype and habitat preference within the crested newt Triturus cristatus superspecies, examined across different ontogenetic stages, provides an excellent setting to explore the pattern of adaptive radiation. The crested newts form a well-supported monophyletic clade for which at least the full mitochondrial DNA phylogeny is resolved. Here we summarise studies that explored the variation in morphological (larval and adult body form, limb skeleton, and skull shape) and other phenotypic traits (early life history, developmental sequences, larval growth rate, and sexual dimorphism) to infer the magnitude and direction of evolutionary changes in crested newts. The phenotypic traits show a high level of concordance in the pattern of variation; there is a cline-like variation, from T. dobrogicus, via T. cristatus, T. carnifex, and T. macedonicus to the T. karelinii group. This pattern matches the cline of ecological preferences; T. dobrogicus is relatively aquatic, followed by T. cristatus. T. macedonicus, T. carnifex, and the T. karelinii group are relatively terrestrial. The observed pattern indicates that phenotypic diversification in crested newts emerged due to an evolutionary switch in ecological preferences. Furthermore, the pattern indicates that heterochronic changes, or changes in the timing and rate of development, underlie the observed phenotypic evolutionary diversification.

  13. Sexual size dimorphism in the evolutionary context of facultative paedomorphosis: insights from European newts

    PubMed Central

    2009-01-01

    Background Sexual size dimorphism (SSD) is a key evolutionary feature that has been studied in many organisms. In a wide range of species, this pattern is more complex because of polymorphism within each sex. However, it is not known whether the magnitude and direction of SSD could be affected by alternative developmental trajectories within sexes. Our aim was to test whether an intrasexual polymorphism, facultative paedomorphosis (a process in which the development of somatic and gonadal tissues differs in alternative morphs), could affect SSD variation patterns in European newts. Results We report here the first evidence that SSD varies depending on the paedomorphic or metamorphic ontogenetic pathway. In species with a consistent female-biased SSD, paedomorphosis decreased the SSD level, but did not affect its direction. In species with moderate female-biased SSD or variable SSD patterns, paedomorphosis changed the magnitude, or both the magnitude and the direction, of SSD. Conclusion Our study highlights the importance of developmental processes for shaping SSD patterns in populations in which contrasting life-history pathways evolved. European newts express different SSD patterns depending on their developmental pathway (i.e., metamorphosis versus paedomorphosis), as well as their species and population. These findings emphasize the importance of studying alternative morphotypes, which are found in a wide range of animal groups, to understand the evolution of SSD. PMID:19954520

  14. Population Genetic Structure of the Endangered Kaiser's Mountain Newt, Neurergus kaiseri (Amphibia: Salamandridae).

    PubMed

    Farasat, Hossein; Akmali, Vahid; Sharifi, Mozafar

    2016-01-01

    Species often exhibit different levels of genetic structuring correlated to their environment. However, understanding how environmental heterogeneity influences genetic variation is difficult because the effects of gene flow, drift and selection are confounded. We investigated the genetic variation and its ecological correlates in an endemic and critically endangered stream breeding mountain newt, Neurergus kaiseri, within its entire range in southwestern Iran. We identified two geographic regions based on phylogenetic relationships using Bayesian inference and maximum likelihood of 779 bp mtDNA (D-loop) in 111 individuals from ten of twelve known breeding populations. This analysis revealed a clear divergence between northern populations, located in more humid habitats at higher elevation, and southern populations, from drier habitats at lower elevations regions. From seven haplotypes found in these populations none was shared between the two regions. Analysis of molecular variance (AMOVA) of N. kaiseri indicates that 94.03% of sequence variation is distributed among newt populations and 5.97% within them. Moreover, a high degree of genetic subdivision, mainly attributable to the existence of significant variance among the two regions is shown (θCT = 0.94, P = 0.002). The positive and significant correlation between geographic and genetic distances (r = 0.61, P = 0.002) following controlling for environmental distance suggests an important influence of geographic divergence of the sites in shaping the genetic variation and may provide tools for a possible conservation based prioritization policy for the endangered species. PMID:26918642

  15. Dining dichotomy: aquatic and terrestrial prey capture behavior in the Himalayan newt Tylototriton verrucosus

    PubMed Central

    De Vylder, Marie

    2016-01-01

    ABSTRACT Transitions between aquatic and terrestrial prey capture are challenging. Trophic shifts demand a high degree of behavioral flexibility to account for different physical circumstances between water and air to keep performance in both environments. The Himalayan newt, Tylototriton verrucosus, is mostly terrestrial but becomes aquatic during its short breeding period. Nonetheless, it was assumed that it lacks the capability of trophic behavioral flexibility, only captures prey on land by its tongue (lingual prehension) and does not feed in water. This theory was challenged from stomach content analyses in wild populations that found a variety of aquatic invertebrates in the newts' stomachs during their breeding season. Accordingly, we hypothesized that T. verrucosus actively changes its terrestrial prey capture mechanism to hunt for aquatic prey at least during its aquatic stage. In fact, the kinematic analyses showed that T. verrucosus uses lingual prehension to capture prey on land but changes to suction feeding for aquatic strikes. The statistical analyses revealed that terrestrial and aquatic strikes differ significantly in most kinematic parameters while behavioral variability does not differ between both behaviors. In turn, the movement patterns in suction feeding showed a higher degree of coordination between jaw and hyoid movements compared to the putative primary feeding mode, namely lingual prehension. We conclude that T. verrucosus, though relatively slow compared to trophic specialists, benefits from a high degree of behavioral flexibility that allows exploiting food sources efficiently from two very different habitats. PMID:27612510

  16. Consequences of metamorphosis for the locomotor performance and thermal physiology of the newt Triturus cristatus.

    PubMed

    Wilson, Robbie S

    2005-01-01

    During metamorphosis, most amphibians undergo rapid shifts in their morphology that allow them to move from an aquatic to a more terrestrial existence. Two important challenges associated with this shift in habitat are the necessity to switch from an aquatic to terrestrial mode of locomotion and changes in the thermal environment. In this study, I investigated the consequences of metamorphosis to the burst swimming and running performance of the European newt Triturus cristatus to determine the nature and magnitude of any locomotor trade-offs that occur across life-history stages. In addition, I investigated whether there were any shifts in the thermal dependence of performance between life-history stages of T. cristatus to compensate for changes in their thermal environment during metamorphosis. A trade-off between swimming and running performance was detected across life-history stages, with metamorphosis resulting in a simultaneous decrease in swimming and increase in running performance. Although the terrestrial habitat of postmetamorphic stages of the newt T. cristatus experienced greater daily fluctuations in temperature than the aquatic habitat of the larval stage, no differences in thermal sensitivity of locomotor performance were detected between the larval aquatic and postmetamorphic stages. The absence of variation across life-history stages of T. cristatus may indicate that thermal sensitivity may be a conservative trait across ontogenetic stages in amphibians, but further studies are required to investigate this assertion.

  17. Brainstem reticulospinal neurons are targets for corticotropin-releasing factor-Induced locomotion in roughskin newts.

    PubMed

    Hubbard, Catherine S; Dolence, E Kurt; Rose, James D

    2010-02-01

    Stress-induced release or central administration of corticotropin-releasing factor (CRF) enhances locomotion in a wide range of vertebrates, including the roughskin newt, Taricha granulosa. Although CRF's stimulatory actions on locomotor behavior are well established, the target neurons through which CRF exerts this effect remain unknown. To identify these target neurons, we utilized a fluorescent conjugate of CRF (CRF-TAMRA 1) to track this peptide's internalization into reticulospinal and other neurons in the medullary reticular formation (MRF), a region critically involved in regulating locomotion. Epifluorescent and confocal microscopy revealed that CRF-TAMRA 1 was internalized by diverse MRF neurons, including reticulospinal neurons retrogradely labeled with Cascade Blue dextran. In addition, we immunohistochemically identified a distinct subset of serotonin-containing neurons, located throughout the medullary raphé, that also internalized the fluorescent CRF-TAMRA 1 conjugate. Chronic single-unit recordings obtained from microwire electrodes in behaving newts revealed that intracerebroventricular (icv) administration of CRF-TAMRA 1 increased medullary neuronal firing and that appearance of this firing was associated with, and strongly predictive of, episodes of CRF-induced locomotion. Furthermore, icv administered CRF-TAMRA 1 produced behavioral and neurophysiological effects identical to equimolar doses of unlabeled CRF. Collectively, these findings provide the first evidence that CRF directly targets reticulospinal and serotonergic neurons in the MRF and indicate that CRF may enhance locomotion via direct effects on the hindbrain, including the reticulospinal system.

  18. Predator-Prey Interactions Shape Thermal Patch Use in a Newt Larvae-Dragonfly Nymph Model

    PubMed Central

    Gvoždík, Lumír; Černická, Eva; Van Damme, Raoul

    2013-01-01

    Thermal quality and predation risk are considered important factors influencing habitat patch use in ectothermic prey. However, how the predator’s food requirement and the prey’s necessity to avoid predation interact with their respective thermoregulatory strategies remains poorly understood. The recently developed ‘thermal game model’ predicts that in the face of imminent predation, prey should divide their time equally among a range of thermal patches. In contrast, predators should concentrate their hunting activities towards warmer patches. In this study, we test these predictions in a laboratory setup and an artificial environment that mimics more natural conditions. In both cases, we scored thermal patch use of newt larvae (prey) and free-ranging dragonfly nymphs (predators). Similar effects were seen in both settings. The newt larvae spent less time in the warm patch if dragonfly nymphs were present. The patch use of the dragonfly nymphs did not change as a function of prey availability, even when the nymphs were starved prior to the experiment. Our behavioral observations partially corroborate predictions of the thermal game model. In line with asymmetric fitness pay-offs in predator-prey interactions (the ‘life-dinner’ principle), the prey’s thermal strategy is more sensitive to the presence of predators than vice versa. PMID:23755175

  19. Seasonal acclimation of preferred body temperatures improves the opportunity for thermoregulation in newts.

    PubMed

    Hadamová, Markéta; Gvoždík, Lumír

    2011-01-01

    Seasonal acclimation and thermoregulation represent major components of complex thermal strategies by which ectotherms cope with the heterogeneity of their thermal environment. Some ectotherms possess the acclimatory capacity to shift seasonally their thermoregulatory behavior, but the frequent use of constant acclimation temperatures during experiments and the lack of information about thermal heterogeneity in the field obscures the ecological relevance of this plastic response. We examined the experimentally induced seasonal acclimation of preferred body temperatures (T(p)) in alpine newts Ichthyosaura (formerly Triturus) alpestris subjected to a gradual increase in acclimation temperature from 5°C during the winter to a constant 15°C or diel fluctuations between 10° and 20°C during the spring/summer. Both the mean and range of T(p) followed the increase in mean acclimation temperature without the influence of diel temperature fluctuations. The direction and magnitude of this acclimatory capacity has the potential to increase the time window available for thermoregulation. Although thermoregulation and thermal acclimation are often considered as separate but coadapted adjustments to thermal heterogeneity, their combined response is employed by newts to tackle seasonal variation in a thermoregulatory-challenging aquatic environment.

  20. Population Genetic Structure of the Endangered Kaiser's Mountain Newt, Neurergus kaiseri (Amphibia: Salamandridae).

    PubMed

    Farasat, Hossein; Akmali, Vahid; Sharifi, Mozafar

    2016-01-01

    Species often exhibit different levels of genetic structuring correlated to their environment. However, understanding how environmental heterogeneity influences genetic variation is difficult because the effects of gene flow, drift and selection are confounded. We investigated the genetic variation and its ecological correlates in an endemic and critically endangered stream breeding mountain newt, Neurergus kaiseri, within its entire range in southwestern Iran. We identified two geographic regions based on phylogenetic relationships using Bayesian inference and maximum likelihood of 779 bp mtDNA (D-loop) in 111 individuals from ten of twelve known breeding populations. This analysis revealed a clear divergence between northern populations, located in more humid habitats at higher elevation, and southern populations, from drier habitats at lower elevations regions. From seven haplotypes found in these populations none was shared between the two regions. Analysis of molecular variance (AMOVA) of N. kaiseri indicates that 94.03% of sequence variation is distributed among newt populations and 5.97% within them. Moreover, a high degree of genetic subdivision, mainly attributable to the existence of significant variance among the two regions is shown (θCT = 0.94, P = 0.002). The positive and significant correlation between geographic and genetic distances (r = 0.61, P = 0.002) following controlling for environmental distance suggests an important influence of geographic divergence of the sites in shaping the genetic variation and may provide tools for a possible conservation based prioritization policy for the endangered species.

  1. Formation of otoconia in the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Astrophysics Data System (ADS)

    Wiederhold, M. L.; Yamashita, M.; Larsen, K.; Asashima, M.

    1994-08-01

    Pre-mated adult female newts and fertilized eggs will be flown on the International Microgravity Laboratory-2 flight, in 1994. One objective of the flight will be to observe the influence of microgravity on the development of the gravity-sensing organs in the inner ear. These organs contain sensory hair cells covered by a layer of dense stones (otoconia). Gravity and linear acceleration exert forces on these masses, leading to excitation of the nerve fibers innervating the hair cells. If the production of the otoliths is regulated to reach an optimal weight, their development might be abnormal in microgravity. Ground-based control experiments are reported describing the developmental sequence in which both the otoliths and their associated sensory epithelium and the semicircular canals appear and develop. Three-dimensional reconstruction of serial sections through the otic vesicle of newt embryos at stages 31 through 58 demonstrate the first appearance, relative position and growth of the otoliths. Reports of experiments in which fertilized frog eggs were flown on a Russian Cosmos mission conclude that the utricular otolith is increased in volume, whereas the saccular otolith maintains normal size, suggesting that at least in the utricle, the weight of the otolith might be regulated.

  2. Seasonal variation of morph ratio in facultatively paedomorphic populations of the palmate newt Triturus helveticus

    NASA Astrophysics Data System (ADS)

    Denoël, Mathieu

    2006-03-01

    Facultative paedomorphosis is a polyphenism in which individuals may express one of two alternative ontogenetic pathways (metamorphosis vs. paedomorphosis) depending on environmental cues. Previous laboratory experiments showed that drying can cause morph ratio change, suggesting that the maintenance of facultative paedomorphosis is highly dependent on environmental determinants. The aim of this study was to examine seasonal variation in morph ratios in eight ponds from Larzac (southern France) naturally inhabited by palmate newts and to relate it to pond drying. In some ponds, the relative proportion of paedomorphs (i.e. individuals retaining gills at the adult stage) increased after the breeding period, but it remained stable or decreased in other ponds. This seasonal variation in the abundance of the two morphs most probably reflects (1) the emigration of metamorphs leaving the pond to occupy terrestrial habitats and (2) metamorphosis of paedomorphic adults in response to drying of the ponds. This study shows that facultative paedomorphosis in palmate newts is a dynamic process that allows rapid change (i.e. within a single year) in morph ratio to fit environmental variation (i.e. risk of drying) within the aquatic habitats. Long-term studies are needed to model the evolution of the dimorphism according to environmental change.

  3. Formation of otoconia in the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Yamashita, M.; Larsen, K.; Asashima, M.

    1994-01-01

    Pre-mated adult female newts and fertilized eggs will be flown on the International Microgravity Laboratory-2 flight, in 1994. One objective of the flight will be to observe the influence of microgravity on the development of the gravity-sensing organs in the inner ear. These organs contain sensory hair cells covered by a layer of dense stones (otoconia). Gravity and linear acceleration exert forces on these masses, leading to excitation of the nerve fibers innervating the hair cells. If the production of the otoliths is regulated to reach an optimal weight, their development might be abnormal in microgravity. Ground-based control experiments are reported describing the developmental sequence in which both the otoliths and their associated sensory epithelium and the semicircular canals appear and develop. Three-dimensional reconstruction of serial sections through the otic vesicle of newt embryos at stages 31 through 58 demonstrate the first appearance, relative position and growth of the otoliths. Reports of experiments in which fertilized frog eggs were flown on a Russian Cosmos mission conclude that the utricular otolith is increased in volume, whereas the saccular otolith maintains normal size, suggesting that at least in the utricle, the weight of the otolith might be regulated.

  4. Reintegration of the regenerated and the remaining tissues during joint regeneration in the newt Cynops pyrrhogaster

    PubMed Central

    Inoue, Takeshi; Yamada, Shigehito

    2015-01-01

    Abstract Urodele amphibians, such as newts, can regenerate a functional limb, including joints, after amputation at any level along the proximal−distal axis of the limb. The blastema can regenerate the limb morphology largely independently of the stump after proximal−distal identity has been established, but the remaining and regenerated tissues must be structurally reintegrated (matched in size and shape). Here we used newt joint regeneration as a model to investigate reintegration, because a functionally interlocking joint requires structural integration between its opposing skeletal elements. After forelimbs were amputated at the elbow joint, the joint was regenerated between the remaining and regenerated skeletal elements. The regenerated cartilage was thick around the amputated joint to make a reciprocally interlocking joint structure with the remaining bone. Furthermore, during regeneration, the extracellular matrix of the remaining tissues was lost, suggesting that the remaining tissues might contribute to the morphogenesis of regenerating cartilage. Our results showed that the area of the regenerated cartilage matched the area of the apposed remaining cartilage, thus contributing to formation of a functional structure. PMID:27499865

  5. Laser irradiation of centrosomes in newt eosinophils: evidence of centriole role in motility

    SciTech Connect

    Koonce, M.P.; Cloney, R.A.; Berns, M.W.

    1984-06-01

    Newt eosinophils are motile granulated leukocytes that uniquely display a highly visible centrosomal area. Electron microscope and tubulin antibody fluorescence confirms the presence of centrioles, pericentriolar material, and radiating microtubules within this visible area. Actin antibodies intensely stain the advancing cell edges and tail but only weakly stain pseudopods being withdrawn into the cell. Randomly activated eosinophils follow a roughly consistent direction with an average rate of 22.5 ..mu..m/min. The position of the centrosome is always located between the trailing cell nucleus and advancing cell edge. If the cell extends more than one pseudopod, the one closest to or containing the centrosome is always the one in which motility continues. Laser irradiation of the visible centrosomal area resulted in rapid cell rounding. After several minutes following irradiation, most cells flattened and movement continued. However, postirradiation motility was uncoordinated and directionless, and the rate decreased to an average of 14.5 ..mu..m/min. Electron microscopy and tubulin immunofluorescence indicated that an initial disorganization of microtubules resulted from the laser microirradiations. After several minutes, organized microtubules reappeared, but the centrioles appeared increasingly damaged. The irregularities in motility due to irradiation are probably related to the damaged centrioles. The results presented in this paper suggest that the centrosome is an important structure in controlling the rate and direction of newt eosinophil motility.

  6. Population Genetic Structure of the Endangered Kaiser’s Mountain Newt, Neurergus kaiseri (Amphibia: Salamandridae)

    PubMed Central

    Farasat, Hossein; Akmali, Vahid; Sharifi, Mozafar

    2016-01-01

    Species often exhibit different levels of genetic structuring correlated to their environment. However, understanding how environmental heterogeneity influences genetic variation is difficult because the effects of gene flow, drift and selection are confounded. We investigated the genetic variation and its ecological correlates in an endemic and critically endangered stream breeding mountain newt, Neurergus kaiseri, within its entire range in southwestern Iran. We identified two geographic regions based on phylogenetic relationships using Bayesian inference and maximum likelihood of 779 bp mtDNA (D-loop) in 111 individuals from ten of twelve known breeding populations. This analysis revealed a clear divergence between northern populations, located in more humid habitats at higher elevation, and southern populations, from drier habitats at lower elevations regions. From seven haplotypes found in these populations none was shared between the two regions. Analysis of molecular variance (AMOVA) of N. kaiseri indicates that 94.03% of sequence variation is distributed among newt populations and 5.97% within them. Moreover, a high degree of genetic subdivision, mainly attributable to the existence of significant variance among the two regions is shown (θCT = 0.94, P = 0.002). The positive and significant correlation between geographic and genetic distances (r = 0.61, P = 0.002) following controlling for environmental distance suggests an important influence of geographic divergence of the sites in shaping the genetic variation and may provide tools for a possible conservation based prioritization policy for the endangered species. PMID:26918642

  7. Analysis of Cell Proliferation in Newt (Pleurodeles waltl) Tissue Regeneration during Spaceflight in Foton M-2

    NASA Technical Reports Server (NTRS)

    Almeida, E. A. C.; Roden, C.; Phillips, J. A.; Yusuf, R.; Globus, R. K.; Searby, N.; Vercoutere, W.; Morey-Holton, E.; Tairbekov, M.; Grigoryan, N.; Domaratskaya, E.; Poplinskaya, V.; Mitashov, V.

    2006-01-01

    Terrestrial organisms exposed to microgravity during spaceflight expe rience musculoskeletal degeneration. It is still not understood if lo nger-term exposures to microgravity induce degeneration in other tiss ues, and if these effects are also observed in neutrally buoyant aqu atic organisms that may be pre-adapted to mechanical unloading. The " Regeneration" experiment conducted collaboratively between Russian an d US scientists for 16 days in the Russian Foton M-2 spaceflight soug ht to test the hypothesis that microgravity alters the proliferation of cells in regenerating tail tissue of the newt Pleurodeles waltl. Our initial results indicate that we successfUlly delivered the proli feration marker 5-bromo-2'-deoxy Uridine (BrdU) during spaceflight, and that it was incorporated in the nuclei of cells in regenerating tis sues. Cells in spaceflight tail regenerates proliferated at a slight ly slower rate and were more undifferentiated than those in ground sy nchronous controls. In addition, the size of regenerating tails from spaceflight was smaller than synchronous controls. However, onboard temperature recordings show that the temperature in spaceflight was a bout 2 C lower than ground synchronous controls, possibly explaining the observed differences. Additional post-facto ground controls at ma tched temperatures will correctly determine the effects of spaceflig ht on regenerative cell proliferation in the newt.

  8. Transcription activator-like effector nucleases efficiently disrupt the target gene in Iberian ribbed newts (Pleurodeles waltl), an experimental model animal for regeneration.

    PubMed

    Hayashi, Toshinori; Sakamoto, Kousuke; Sakuma, Tetsushi; Yokotani, Naoki; Inoue, Takeshi; Kawaguchi, Eri; Agata, Kiyokazu; Yamamoto, Takashi; Takeuchi, Takashi

    2014-01-01

    Regeneration of a lost tissue in an animal is an important issue. Although regenerative studies have a history of research spanning more than a century, the gene functions underlying regulation of the regeneration are mostly unclear. Analysis of knockout animals is a very powerful tool with which to elucidate gene function. Recently, transcription activator-like effector nucleases (TALENs) have been developed as an effective technique for genome editing. This technique enables gene targeting in amphibians such as newts that were previously impossible. Here we show that newts microinjected with TALEN mRNAs designed for targeting the tyrosinase gene in single-cell stage embryos revealed an albino phenotype. Sequence analysis revealed that the tyrosinase genes were effectively disrupted in these albino newts. Moreover, precise genome alteration was achieved using TALENs and single strand oligodeoxyribonucleotides. Our results suggest that TALENs are powerful tools for genome editing for regenerative research in newts.

  9. Cytopathologic observations of the lung of adult newts (Cynops pyrrhogaster) on-board the space shuttle, Columbia, during the Second International Microgravity Laboratory experiments.

    PubMed

    Pfeiffer, C J; Yamashita, M; Izumi-Kurotani, A; Koike, H; Asashima, M

    1995-10-01

    Four adult female Japanese newts, Cynops pyrrhogaster, were carried for 15 days aboard the orbiting space shuttle, Columbia, in July of 1994, as part of the Second International Microgravity Laboratory, IML-2 aquatic animal experiments. These previously fertilized newts, after stimulation with chorionic gonadotropin by a spaceflight adapted injection procedure, deposited numerous eggs for study of early development during weightlessness. The primitive saccular lungs of the two newts which survived the spaceflight revealed by TEM marked pulmonary cytopathologic changes including basal laminar separation, microvillar degeneration, and cytoplasmic granular changes in the primary granulated pneumocytes. Also, intracellular edema in the pulmonary collagenous matrix and vacuolar changes in the ciliated pulmonary lining cell type and in vascular endothelial cells were observed. These changes, triggered by the spaceflight, and not seen in controls also relying on respiration via the skin, may reflect a chronic mild hypoxia as it is known that newts undergoing oviposition are subject to increased oxygen demand.

  10. Multi-tissue microarray analysis identifies a molecular signature of regeneration.

    PubMed

    Mercer, Sarah E; Cheng, Chia-Ho; Atkinson, Donald L; Krcmery, Jennifer; Guzman, Claudia E; Kent, David T; Zukor, Katherine; Marx, Kenneth A; Odelberg, Shannon J; Simon, Hans-Georg

    2012-01-01

    The inability to functionally repair tissues that are lost as a consequence of disease or injury remains a significant challenge for regenerative medicine. The molecular and cellular processes involved in complete restoration of tissue architecture and function are expected to be complex and remain largely unknown. Unlike humans, certain salamanders can completely regenerate injured tissues and lost appendages without scar formation. A parsimonious hypothesis would predict that all of these regenerative activities are regulated, at least in part, by a common set of genes. To test this hypothesis and identify genes that might control conserved regenerative processes, we performed a comprehensive microarray analysis of the early regenerative response in five regeneration-competent tissues from the newt Notophthalmus viridescens. Consistent with this hypothesis, we established a molecular signature for regeneration that consists of common genes or gene family members that exhibit dynamic differential regulation during regeneration in multiple tissue types. These genes include members of the matrix metalloproteinase family and its regulators, extracellular matrix components, genes involved in controlling cytoskeleton dynamics, and a variety of immune response factors. Gene Ontology term enrichment analysis validated and supported their functional activities in conserved regenerative processes. Surprisingly, dendrogram clustering and RadViz classification also revealed that each regenerative tissue had its own unique temporal expression profile, pointing to an inherent tissue-specific regenerative gene program. These new findings demand a reconsideration of how we conceptualize regenerative processes and how we devise new strategies for regenerative medicine.

  11. Multi-Tissue Microarray Analysis Identifies a Molecular Signature of Regeneration

    PubMed Central

    Mercer, Sarah E.; Cheng, Chia-Ho; Atkinson, Donald L.; Krcmery, Jennifer; Guzman, Claudia E.; Kent, David T.; Zukor, Katherine; Marx, Kenneth A.; Odelberg, Shannon J.; Simon, Hans-Georg

    2012-01-01

    The inability to functionally repair tissues that are lost as a consequence of disease or injury remains a significant challenge for regenerative medicine. The molecular and cellular processes involved in complete restoration of tissue architecture and function are expected to be complex and remain largely unknown. Unlike humans, certain salamanders can completely regenerate injured tissues and lost appendages without scar formation. A parsimonious hypothesis would predict that all of these regenerative activities are regulated, at least in part, by a common set of genes. To test this hypothesis and identify genes that might control conserved regenerative processes, we performed a comprehensive microarray analysis of the early regenerative response in five regeneration-competent tissues from the newt Notophthalmus viridescens. Consistent with this hypothesis, we established a molecular signature for regeneration that consists of common genes or gene family members that exhibit dynamic differential regulation during regeneration in multiple tissue types. These genes include members of the matrix metalloproteinase family and its regulators, extracellular matrix components, genes involved in controlling cytoskeleton dynamics, and a variety of immune response factors. Gene Ontology term enrichment analysis validated and supported their functional activities in conserved regenerative processes. Surprisingly, dendrogram clustering and RadViz classification also revealed that each regenerative tissue had its own unique temporal expression profile, pointing to an inherent tissue-specific regenerative gene program. These new findings demand a reconsideration of how we conceptualize regenerative processes and how we devise new strategies for regenerative medicine. PMID:23300656

  12. The lethal impacts of Roundup and predatory stress on six species of North American tadpoles.

    PubMed

    Relyea, R A

    2005-04-01

    The decline in amphibians across the globe has sparked a search for the causes, and recent evidence suggests a connection with pesticides. However, for most pesticides, tests on amphibians are rare and conducted only for short durations (1 to 4 days) and without natural stressors. Recent studies have discovered that the stress of predator cues in the water can make insecticides much more lethal to larval amphibians, but it is unknown whether this phenomenon can be generalized to other types of pesticides. Using six species of North American amphibian larvae (Rana sylvatica, R. pipiens, R. clamitans, R. catesbeiana, Bufo americanus, and Hyla versicolor), I examined the impact of a globally common herbicide (Roundup) on the survival of tadpoles for 16 days with and without the chemical cues emitted by predatory newts (Notophthalmus viridescens). LC50(16-d) estimates varied from 0.55 to 2.52 mg of active ingredient (AI)/L, which was considerably lower than the few previous studies using Roundup (1.5 to 15.5 mg AI/L). Moreover, in one of the six species tested (R. sylvatica), the addition of predatory stress made Roundup twice as lethal. This discovery suggests that synergistic interactions between predatory stress and pesticides may indeed be a generalizable phenomenon in amphibians that occurs with a wide variety of pesticides. PMID:15886853

  13. The Husting dilemma: A methodological note

    USGS Publications Warehouse

    Nichols, J.D.; Hepp, G.R.; Pollock, K.H.; Hines, J.E.

    1987-01-01

    Recently, Gill (1985) discussed the interpretation of capture history data resulting from his own studies on the red-spotted newt, Notophthalmus viridescens , and work by Husting (1965) on spotted salamanders, Ambystoma maculatum. Gill (1985) noted that gaps in capture histories (years in which individuals were not captured, preceded and followed by years in which they were) could result from either of two very different possibilities: (1) failure of the animal to return to the fenced pond to breed (the alternative Husting (1965) favored), or (2) return of the animal to the breeding pond, but failure of the investigator to capture it and detect its presence. The authors agree entirely with Gill (1985) that capture history data such as his or those of Husting (1965) should be analyzed using models that recognize the possibility of 'census error,' and that it is important to try to distinguish between such 'error' and skipped breeding efforts. The purpose of this note is to point out the relationship between Gill's (1985:347) null model and certain capture-recapture models, and to use capture-recapture models and tests to analyze the original data of Husting (1965).

  14. Newt tail regeneration: a model for gravity-dependent morphogenesis and clues to the molecular mechanisms involved.

    NASA Astrophysics Data System (ADS)

    Radugina, Elena A.; Almeida, Eduardo; Grigoryan, Eleonora

    Gravity alterations are widely recognized to influence living systems. They may cause temporary or permanent effects on physiology and development at different levels, from gene expression to morphogenesis. However, the molecular mechanisms underlying these effects are often unclear, and adequate model systems to study them are required. To address this problem we developed a new experimental model of how gravity affects morphogenesis during tail regeneration in the newt Pleurodeles waltl. The effects of increased gravity on newt tail morphogenesis were first documented in two joint Russian-US NASA spaceflight experiments in the Russian Foton-M2 (2005) and Foton-M3 (2007) missions. In these experiments the shape of newt tail regenerate was found to depend on the gravity level, being dorso-ventrally symmetrical in microgravity and in neutrally-buoyant aquarium controls, versus hook-like and bent downward in 1g controls. These 1g controls were conducted in spaceflight habitats using a water-saturated PVA sponge mat. These results were reproducible in multiple spaceflight, and ground laboratory studies, both in the US at NASA ARC and in Russia at IDB RAS, and were characterized in detail using morphometry and histology approaches. The role of hypergravity in shaping morphogenesis was confirmed at NASA ARC with an experiment in the ISS Testbed 8-foot diameter centrifuge operating at 2g. Animals that experienced two-week centrifugation (the period of time used in the Foton flights) developed the same hook-like regenerates as 1g controls, and morphometric analysis revealed no significant difference between 1g and 2g groups, however both were significantly different from aquarium controls. We hypothesize that exposure to 1g or 2g during tail morphogenesis constitutes excessive loading for newts that are adapted to microgravity-like conditions in their aquatic habitat. Because Heat Shock Proteins (HSPs) are stress-induced molecules that respond to a broad variety of

  15. Peculiarities of lens and tail regeneration detected in newts after spaceflight aboard Foton M3

    NASA Astrophysics Data System (ADS)

    Grigoryan, Eleonora N.; Almeida, Eduardo; Poplinskaya, Valentina; Novikova, Julia; Domaratskaya, Elena; Aleinikova, Karina; Souza, Kenneth; Skidmore, Mike; Grigoryan, Eleonora N.

    In September 2007 the joint, 12 day long experiment was carried out aboard Russian satellite Foton M3. The goal of the experiment was to study eye lens, tail and forelimb toe regeneration in adult 16 newts (Pl. waltl.) operated 10 days before taking-off. In spaceflight and synchronous ground control we used video recording, temperature and irradiation control, as well as constant availability of thymidine analog BrdU for its absorption via animals' skin. New techniques allowed us to analyze animals' behavior in hyperand microgravity periods of time, to take proper account of spaceflight factors, and measure accumulated pools of DNA-synthesizing cells in regenerating tissues. All tissue specimens obtained from animals were isolated in the day of landing and then prepared for morphological, immunochemical and molecular investigations. Synchronous control was shifted for two days and reproduced flight conditions except changes of gravity influence. As a result in flown animals as compared with synchronous ground control we found lens regeneration of 0.5-1 stage speeded up and an increased BrdU+ (S-phase) cell number in eye cornea, growth zone, limbus and newly forming lens. These features of regeneration were accompanied by an increase of FGF2 expression in eye growth zone and heat shock protein (HSP90) induction purely in retinal macroglial cells of regenerating eyes. Toe regeneration rate was equal and achieved the stage of accomplished healing of amputation area in both groups - "flown" and control animals. We found no essential differences in tail regeneration rate and tail regenerate sizes in the newts exposed to space and on ground. In both groups tail regeneration reached the stage IV-V when tail length and square were around 4.4 mm and 15.5 mm2, correspondingly. However we did observe remarkable changes of tail regenerate form and some of pigmentation. Computer morphometrical analysis showed that only in ground control animals the evident dorso

  16. Confirmation of the absence of tetrodotoxin and its analogues in the juveniles of the Japanese fire-bellied newt, Cynops pyrrhogaster, captive-reared from eggs in the laboratory using HILIC-LC-MS.

    PubMed

    Kudo, Yuta; Chiba, Chikafumi; Konoki, Keiichi; Cho, Yuko; Yotsu-Yamashita, Mari

    2015-07-01

    The tetrodotoxin (TTX) contents of the Japanese fire-bellied newt, Cynops pyrrhogaster, captive-reared from eggs to metamorphosed juveniles with a non-toxic diet for 70 weeks, as well as wild-caught juvenile newts, were investigated using a high-resolution hydrophilic interaction chromatography-LC-MS. TTX was detected in 0- to 22-week-old captive-reared juvenile newts but was not detected (<15 ng/g) in the 36- to 70-week-old newts, while significant levels of TTX (1.3-14 μg/g) were detected in the wild-caught juveniles. PMID:25986913

  17. Confirmation of the absence of tetrodotoxin and its analogues in the juveniles of the Japanese fire-bellied newt, Cynops pyrrhogaster, captive-reared from eggs in the laboratory using HILIC-LC-MS.

    PubMed

    Kudo, Yuta; Chiba, Chikafumi; Konoki, Keiichi; Cho, Yuko; Yotsu-Yamashita, Mari

    2015-07-01

    The tetrodotoxin (TTX) contents of the Japanese fire-bellied newt, Cynops pyrrhogaster, captive-reared from eggs to metamorphosed juveniles with a non-toxic diet for 70 weeks, as well as wild-caught juvenile newts, were investigated using a high-resolution hydrophilic interaction chromatography-LC-MS. TTX was detected in 0- to 22-week-old captive-reared juvenile newts but was not detected (<15 ng/g) in the 36- to 70-week-old newts, while significant levels of TTX (1.3-14 μg/g) were detected in the wild-caught juveniles.

  18. UV wavelengths experienced during development affect larval newt visual sensitivity and predation efficiency.

    PubMed

    Martin, Mélissa; Théry, Marc; Rodgers, Gwendolen; Goven, Delphine; Sourice, Stéphane; Mège, Pascal; Secondi, Jean

    2016-02-01

    We experimentally investigated the influence of developmental plasticity of ultraviolet (UV) visual sensitivity on predation efficiency of the larval smooth newt, Lissotriton vulgaris. We quantified expression of SWS1 opsin gene (UV-sensitive protein of photoreceptor cells) in the retinas of individuals who had developed in the presence (UV+) or absence (UV-) of UV light (developmental treatments), and tested their predation efficiency under UV+ and UV- light (testing treatments). We found that both SWS1 opsin expression and predation efficiency were significantly reduced in the UV- developmental group. Larvae in the UV- testing environment displayed consistently lower predation efficiency regardless of their developmental treatment. These results prove for the first time, we believe, functional UV vision and developmental plasticity of UV sensitivity in an amphibian at the larval stage. They also demonstrate that UV wavelengths enhance predation efficiency and suggest that the magnitude of the behavioural response depends on retinal properties induced by the developmental lighting environment.

  19. Ultraviolet microbeam irradiations of cultured newt lung epithelial cells during mitosis

    SciTech Connect

    Cypher, C.

    1983-01-01

    The mechanism of chromosome movement is unknown. The structural environment for this movement is a birefringent, spindle-shaped array of microtubules. Microbeams of ultraviolet light were used to disrupt the mitotic spindles of newt lung epithelial cells to localize force production within spindles and to evaluate the role of microtubules in force generation or transduction. Time-lapse cinephotomicrographic records of cells were made using phase and polarization microscopy. Irradiation effects were correlated with spindle microtubule structure by immuno-gold antitubulin staining. The results demonstrate the pervasive effects of local irradiations upon spindle structure. The spindle compaction observed after irradiations suggests that each half-spindle is under a compressive force. Since the irradiations locally disassemble microtubules, the results suggest that the birefringent microtubules oppose this compressive force.

  20. Influence of respirometry methods on intraspecific variation in standard metabolic rates in newts.

    PubMed

    Kristín, Peter; Gvoždík, Lumír

    2012-09-01

    Standard metabolic rate (SMR) is both a highly informative and variable trait. Variation in SMR stems not only from diverse intrinsic and extrinsic factors, but also from the use of diverse methods for metabolic measurements. We measured CO(2) production (VCO(2)) and oxygen consumption rates (VO(2)) using two flow-through respirometry modes, continuous and intermittent (stop-flow), to evaluate their potential contribution to SMR variation in Alpine newts, Ichthyosaura alpestris. Both respirometry modes yielded similar and repeatable VCO(2) values. Although VO(2) was highly repeatable, continuous respirometry produced lower VO(2) than the intermittent method. During intermittent measurements, the total number of activity bouts was higher than during continuous respirometry trials. Statistical correction for disparate activity levels minimized variation in oxygen consumption between respirometry modes. We conclude that use of either method of flow-through respirometry, if properly applied, introduced less noise to SMR estimates than a variation in activity levels.

  1. Controlling gene loss of function in newts with emphasis on lens regeneration.

    PubMed

    Tsonis, Panagiotis A; Haynes, Tracy; Maki, Nobuyasu; Nakamura, Kenta; Casco-Robles, Martin Miguel; Yamada, Shouta; Miura, Tomoya; Chiba, Chikafumi; Del Rio-Tsonis, Katia

    2011-05-01

    Here we describe a protocol for gene loss of function during regeneration in newts, specifically applied to lens regeneration. Knockdown with the use of morpholinos can be achieved both in vitro and in vivo, depending on the experimental design. These methods achieve desirable levels of gene knockdown, and thus can be compared with methods developed for use in other animals, such as zebrafish. The technology has been applied to study molecular mechanisms during the process of lens regeneration by knocking down genes at specific stages and examining their effects on other genes and lens differentiation. The protocol can take a few days or up to 20 d to complete, depending on the duration of the experiment.

  2. A case of reproductive character displacement in female palmate newts (Lissotriton helveticus).

    PubMed

    Johanet, Aurélie; Secondi, Jean; Pays, Olivier; Pagano, Alain; Lodé, Thierry; Lemaire, Christophe

    2009-06-01

    Reproductive character displacement is commonly described as larger phenotypic differences between species living in sympatry rather than in allopatry. We investigated this phenomenon on two amphibians found in their contact zone where syntopic and allotopic sites alternate. To test the effect of syntopy with Lissotriton vulgaris on the Lissotriton helveticus phenotype, we studied the morphology of adult males and females while controlling for environmental factors (i.e. land use and flood risk). Using linear mixed-effects models, we found that females of L. helveticus expressed a deeper tail when in the presence of the other species, a pattern consistent with reproductive character displacement. This pattern has been rarely observed in Amphibians. It suggests that male newts incur large mating costs when selecting heterospecific partners. Our study also emphasizes that the evolution of mate recognition systems could occur at a microgeographical scale within a sympatric area.

  3. UV wavelengths experienced during development affect larval newt visual sensitivity and predation efficiency.

    PubMed

    Martin, Mélissa; Théry, Marc; Rodgers, Gwendolen; Goven, Delphine; Sourice, Stéphane; Mège, Pascal; Secondi, Jean

    2016-02-01

    We experimentally investigated the influence of developmental plasticity of ultraviolet (UV) visual sensitivity on predation efficiency of the larval smooth newt, Lissotriton vulgaris. We quantified expression of SWS1 opsin gene (UV-sensitive protein of photoreceptor cells) in the retinas of individuals who had developed in the presence (UV+) or absence (UV-) of UV light (developmental treatments), and tested their predation efficiency under UV+ and UV- light (testing treatments). We found that both SWS1 opsin expression and predation efficiency were significantly reduced in the UV- developmental group. Larvae in the UV- testing environment displayed consistently lower predation efficiency regardless of their developmental treatment. These results prove for the first time, we believe, functional UV vision and developmental plasticity of UV sensitivity in an amphibian at the larval stage. They also demonstrate that UV wavelengths enhance predation efficiency and suggest that the magnitude of the behavioural response depends on retinal properties induced by the developmental lighting environment. PMID:26843556

  4. Scanning and transmission electron microscopic study of the lung of the newt, Triturus alpestris Laur.

    PubMed

    Goniakowska-Witalińska, L

    1980-01-01

    The lungs of Triturus alpestris Laur. were investigated with the scanning and transmission electron microscopes. Dimensions of the cell bodies of pneumocytes and ciliated cells, as well as the thickness of the air-blood barrier, were determined. The lungs of the newt form two simple sacs without septa. A ciliated epithelium containing goblet cells lines the pulmonary vein and partially the pulmonary artery. The remainder of the lung surface is covered internally by respiratory epithelium consisting of one type of cell and only occasionally showing the presence of single ciliated cells. All cells, ciliated, goblet and pneumocytes, contain in their cytoplasm lamellar bodies. Multivesicular bodies and numerous vesicles of variable electron density also occur in the cytoplasm of pneumocytes. Atypical mitochondria can be found in all cell types of the lung. Fixation with addition of tannic acid reveals the surface lining film. Tubular myelin figures were not observed.

  5. Hyaluronic acid production and hyaluronidase activity in the newt iris during lens regeneration

    SciTech Connect

    Kulyk, W.M.; Zalik, S.E.; Dimitrov, E.

    1987-09-01

    The process of lens regeneration in newts involves the dedifferentiation of pigmented iris epithelial cells and their subsequent conversion into lens fibers. In vivo this cell-type conversion is restricted to the dorsal region of the iris. We have examined the patterns of hyaluronate accumulation and endogenous hyaluronidase activity in the newt iris during the course of lens regeneration in vivo. Accumulation of newly synthesized hyaluronate was estimated from the uptake of (/sup 3/H)glucosamine into cetylpyridinium chloride-precipitable material that was sensitive to Streptomyces hyaluronidase. Endogenous hyaluronidase activity was determined from the quantity of reducing N-acetylhexosamine released upon incubation of iris tissue extract with exogenous hyaluronate substrate. We found that incorporation of label into hyaluronate was consistently higher in the regeneration-activated irises of lentectomized eyes than in control irises from sham-operated eyes. Hyaluronate labeling was higher in the dorsal (lens-forming) region of the iris than in ventral (non-lens-forming) iris tissue during the regeneration process. Label accumulation into hyaluronate was maximum between 10 and 15 days after lentectomy, the period of most pronounced dedifferentiation in the dorsal iris epithelium. Both normal and regenerating irises demonstrated a high level of endogenous hyaluronidase activity with a pH optimum of 3.5-4.0. Hyaluronidase activity was 1.7 to 2 times higher in dorsal iris tissue than in ventral irises both prior to lentectomy and throughout the regeneration process. We suggest that enhanced hyaluronate accumulation may facilitate the dedifferentiation of iris epithelial cells in the dorsal iris and prevent precocious withdrawal from the cell cycle. The high level of hyaluronidase activity in the dorsal iris may promote the turnover and remodeling of extracellular matrix components required for cell-type conversion.

  6. Divergence in the face of gene flow: the case of two newts (amphibia: salamandridae).

    PubMed

    Nadachowska, Krystyna; Babik, Wieslaw

    2009-04-01

    Understanding the process of divergence requires the quantitative characterization of patterns of gene flow between diverging taxa. New and powerful coalescent-based methods give insight into these processes in unprecedented details by enabling the reconstruction of the temporal distribution of past gene flow. Here, we use sequence variation at eight nuclear markers and mitochondrial DNA (mtDNA) in multiple populations to study diversity, divergence, and gene flow between two subspecies of a salamander, the smooth newt (Lissotriton vulgaris kosswigi and Lissotriton vulgaris vulgaris) in Turkey. The ranges of both subspecies encompass mainly the areas of this important glacial refugial area. Populations in refugia where species have been present for a long time and differentiated in situ should better preserve the record of past gene flow than young populations in postglacial expansion areas. Sequence diversity in both subspecies was substantial (nuclear pi(sil) = 0.69% and 1.31%). We detected long-term demographic stability in these refugial populations with large effective population sizes (N(e)) of the order of 1.5-3 x 10(5) individuals. Gene trees and the isolation with migration (IM) analysis complemented by tests of nested IM models showed that despite deep, pre-Pleistocene divergence of the studied newts, asymmetric introgression from vulgaris to kosswigi has occurred, with signatures of recent gene flow in mtDNA and an anonymous nuclear marker, and evidence for more ancient introgression in nuclear introns. The distribution of migration times raises the intriguing possibility that even the initial divergence may have occurred in the face of gene flow.

  7. Context-Dependent Plastic Response during Egg-Laying in a Widespread Newt Species

    PubMed Central

    Tóth, Zoltán

    2015-01-01

    Previous research on predator-induced phenotypic plasticity mostly focused on responses in morphology, developmental time and/or behaviour during early life stages, but the potential significance of anticipatory parental responses has been investigated less often. In this study I examined behavioural and maternal responses of gravid female smooth newts, Lissotriton vulgaris, in the presence of chemical cues originating from invertebrate predators, Acilius sulcatus water beetles and Aeshna cyanea dragonfly larvae. More specifically, I tested the extent of oviposition preference, plasticity in egg-wrapping behaviour and plasticity in egg size when females had the possibility to lay eggs at oviposition sites with and without predator cues during overnight trials. I found that individuals did not avoid laying eggs in the environment with predator cues; however, individuals that deposited eggs into both environments adjusted the size of the laid eggs to the perceived environment. Females deposited larger eggs earlier in the season but egg size decreased with time in the absence of predator cues, whereas individuals laid eggs of average size throughout the investigated reproductive period when such cues were present. Also, egg size was found to be positively related to hatching success. Individuals did not adjust their wrapping behaviour to the presence of predator cues, but females differed in the extent of egg-wrapping between ponds. Females’ body mass and tail depth were also different between ponds, whereas their body size was positively associated with egg size. According to these results, female smooth newts have the potential to exhibit activational plasticity and invest differently into eggs depending on temporal and environmental factors. Such an anticipatory response may contribute to the success of this caudate species under a wide range of predator regimes at its natural breeding habitats. PMID:26291328

  8. Context-Dependent Plastic Response during Egg-Laying in a Widespread Newt Species.

    PubMed

    Tóth, Zoltán

    2015-01-01

    Previous research on predator-induced phenotypic plasticity mostly focused on responses in morphology, developmental time and/or behaviour during early life stages, but the potential significance of anticipatory parental responses has been investigated less often. In this study I examined behavioural and maternal responses of gravid female smooth newts, Lissotriton vulgaris, in the presence of chemical cues originating from invertebrate predators, Acilius sulcatus water beetles and Aeshna cyanea dragonfly larvae. More specifically, I tested the extent of oviposition preference, plasticity in egg-wrapping behaviour and plasticity in egg size when females had the possibility to lay eggs at oviposition sites with and without predator cues during overnight trials. I found that individuals did not avoid laying eggs in the environment with predator cues; however, individuals that deposited eggs into both environments adjusted the size of the laid eggs to the perceived environment. Females deposited larger eggs earlier in the season but egg size decreased with time in the absence of predator cues, whereas individuals laid eggs of average size throughout the investigated reproductive period when such cues were present. Also, egg size was found to be positively related to hatching success. Individuals did not adjust their wrapping behaviour to the presence of predator cues, but females differed in the extent of egg-wrapping between ponds. Females' body mass and tail depth were also different between ponds, whereas their body size was positively associated with egg size. According to these results, female smooth newts have the potential to exhibit activational plasticity and invest differently into eggs depending on temporal and environmental factors. Such an anticipatory response may contribute to the success of this caudate species under a wide range of predator regimes at its natural breeding habitats. PMID:26291328

  9. Contrasting patterns of variation in MHC loci in the Alpine newt.

    PubMed

    Babik, W; Pabijan, M; Radwan, J

    2008-05-01

    Major histocompatibility complex (MHC) genes are essential in pathogen recognition and triggering an adaptive immune response. Although they are the most polymorphic genes in vertebrates, very little information on MHC variation and patterns of evolution are available for amphibians, a group known to be declining rapidly worldwide. As infectious diseases are invoked in the declines, information on MHC variation should contribute to devising appropriate conservation strategies. In this study, we examined MHC variation in 149 Alpine newts (Mesotriton alpestris) from three allopatric population groups in Poland at the northeastern margin of the distribution of this species. The genetic distinctiveness of the population groups has previously been shown by studies of skin graft rejection, allozymes and microsatellites. Two putative expressed MHC II loci with contrasting levels of variation and clear evidence of gene conversion/recombination between them were detected. The Meal-DAB locus is highly polymorphic (37 alleles), and shows evidence of historical positive selection for amino acid replacements and substantial geographical differentiation in allelic richness. On the contrary, the Meal-DBB locus exhibits low polymorphism (three alleles differing by up to two synonymous substitutions) and a uniform distribution of three alleles among geographical regions. The uniform frequencies of the presumptively neutral Meal-DBB alleles may be explained by linkage to Meal-DAB. We found differences in allelic richness in Meal-DAB between regions, consistent with the hypothesis that genetic drift prevails with increasing distance from glacial refugia. Pseudogene loci appear to have evolved neutrally. The level of DAB variation correlated with variation in microsatellite loci, implying that selection and drift interplayed to produce the pattern of MHC variation observed in marginal populations of the Alpine newt.

  10. Context-Dependent Plastic Response during Egg-Laying in a Widespread Newt Species.

    PubMed

    Tóth, Zoltán

    2015-01-01

    Previous research on predator-induced phenotypic plasticity mostly focused on responses in morphology, developmental time and/or behaviour during early life stages, but the potential significance of anticipatory parental responses has been investigated less often. In this study I examined behavioural and maternal responses of gravid female smooth newts, Lissotriton vulgaris, in the presence of chemical cues originating from invertebrate predators, Acilius sulcatus water beetles and Aeshna cyanea dragonfly larvae. More specifically, I tested the extent of oviposition preference, plasticity in egg-wrapping behaviour and plasticity in egg size when females had the possibility to lay eggs at oviposition sites with and without predator cues during overnight trials. I found that individuals did not avoid laying eggs in the environment with predator cues; however, individuals that deposited eggs into both environments adjusted the size of the laid eggs to the perceived environment. Females deposited larger eggs earlier in the season but egg size decreased with time in the absence of predator cues, whereas individuals laid eggs of average size throughout the investigated reproductive period when such cues were present. Also, egg size was found to be positively related to hatching success. Individuals did not adjust their wrapping behaviour to the presence of predator cues, but females differed in the extent of egg-wrapping between ponds. Females' body mass and tail depth were also different between ponds, whereas their body size was positively associated with egg size. According to these results, female smooth newts have the potential to exhibit activational plasticity and invest differently into eggs depending on temporal and environmental factors. Such an anticipatory response may contribute to the success of this caudate species under a wide range of predator regimes at its natural breeding habitats.

  11. Isolation and Structural Determination of the First 8-epi-type Tetrodotoxin Analogs from the Newt, Cynops ensicauda popei, and Comparison of Tetrodotoxin Analogs Profiles of This Newt and the Puffer Fish, Fugu poecilonotus

    PubMed Central

    Kudo, Yuta; Yasumoto, Takeshi; Konoki, Keiichi; Cho, Yuko; Yotsu-Yamashita, Mari

    2012-01-01

    Identification of new tetrodotoxin (TTX) analogs from TTX-possessing animals might provide insight into its biosynthesis and metabolism. In this study, four new analogs, 8-epi-5,6,11-trideoxyTTX, 4,9-anhydro-8-epi-5,6,11-trideoxyTTX, 1-hydroxy-8-epi-5,6,11-trideoxyTTX, and 1-hydroxy-4,4a-anhydro-8-epi-5,6,11-trideoxyTTX, were isolated from the newt, Cynops ensicauda popei, and their structures were determined using spectroscopic methods. These are the first 8-epi-type analogs of TTX that have been found in a natural source. Furthermore, we examined the composition of the TTX analogs in this newt and in the ovary of the puffer fish, Fugu poecilonotus, using LC/MS. The results indicate that TTX and 11-deoxyTTX were present in both sources. However, 6-epiTTX and 8-epi-type analogs were detected only in the newt, while 5,6,11-trideoxyTTX was a specific and major analog in the puffer fish. Such considerable differences among analog compositions might reflect differences in the biosynthesis or metabolism of TTX between these animals. PMID:22611361

  12. Environmental changes in oxygen tension reveal ROS-dependent neurogenesis and regeneration in the adult newt brain.

    PubMed

    Hameed, L Shahul; Berg, Daniel A; Belnoue, Laure; Jensen, Lasse D; Cao, Yihai; Simon, András

    2015-01-01

    Organisms need to adapt to the ecological constraints in their habitat. How specific processes reflect such adaptations are difficult to model experimentally. We tested whether environmental shifts in oxygen tension lead to events in the adult newt brain that share features with processes occurring during neuronal regeneration under normoxia. By experimental simulation of varying oxygen concentrations, we show that hypoxia followed by re-oxygenation lead to neuronal death and hallmarks of an injury response, including activation of neural stem cells ultimately leading to neurogenesis. Neural stem cells accumulate reactive oxygen species (ROS) during re-oxygenation and inhibition of ROS biosynthesis counteracts their proliferation as well as neurogenesis. Importantly, regeneration of dopamine neurons under normoxia also depends on ROS-production. These data demonstrate a role for ROS-production in neurogenesis in newts and suggest that this role may have been recruited to the capacity to replace lost neurons in the brain of an adult vertebrate. PMID:26485032

  13. Ranavirus infection in a group of wild-caught Lake Urmia newts Neurergus crocatus imported from Iraq into Germany.

    PubMed

    Stöhr, Anke C; Fleck, Jürgen; Mutschmann, Frank; Marschang, Rachel E

    2013-04-11

    High mortality, in association with anorexia and skin ulcerations, occurred in a group of wild-caught Lake Urmia newts Neurergus crocatus, imported from Iraq in 2011. Predominant findings in the pathological examinations consisted of systemic hemorrhages and ulcerative dermatitis. Ranavirus DNA was detected via PCR in 2 of 3 dead animals, and a part of the major capsid protein (MCP) gene was sequenced. The analyzed portion of the MCP gene was 99% identical to the corresponding portion of the frog virus 3 genome. This is the first description of a ranavirus in Lake Urmia newts and in wild-caught amphibians from Iraq, as well as the first description of ranavirus infection in a urodele from the Middle East.

  14. Environmental changes in oxygen tension reveal ROS-dependent neurogenesis and regeneration in the adult newt brain.

    PubMed

    Hameed, L Shahul; Berg, Daniel A; Belnoue, Laure; Jensen, Lasse D; Cao, Yihai; Simon, András

    2015-10-20

    Organisms need to adapt to the ecological constraints in their habitat. How specific processes reflect such adaptations are difficult to model experimentally. We tested whether environmental shifts in oxygen tension lead to events in the adult newt brain that share features with processes occurring during neuronal regeneration under normoxia. By experimental simulation of varying oxygen concentrations, we show that hypoxia followed by re-oxygenation lead to neuronal death and hallmarks of an injury response, including activation of neural stem cells ultimately leading to neurogenesis. Neural stem cells accumulate reactive oxygen species (ROS) during re-oxygenation and inhibition of ROS biosynthesis counteracts their proliferation as well as neurogenesis. Importantly, regeneration of dopamine neurons under normoxia also depends on ROS-production. These data demonstrate a role for ROS-production in neurogenesis in newts and suggest that this role may have been recruited to the capacity to replace lost neurons in the brain of an adult vertebrate.

  15. Choroidal and iris angioarchitecture of the newt: a scanning electron-microscopic study of vascular corrosion casts.

    PubMed

    Lazzari, M; Franceschini, V; Minelli, G; Ciani, F

    1993-04-15

    The corrosion cast technique provided for the first time an excellent three-dimensional visualization of the vascular pattern of the choroid and iris in the newt eye. The results show the presence of a single arterial afference to the choroidal and iris capillaries: the ophthalmic artery is the origin of both ciliary arteries and the long posterior ciliary artery. Slightly behind the equatorial circumference of the eyeball the venous drainage consists of a single vessel on the dorsal side and two distinct vessels on the ventral one. It receives blood from both iris and choroid. The surface of the plastic endocasts shows some details of fine luminal structures of the endothelial cells. Shallow depressions may be regarded as imprints of endothelial cell nuclei, and they are distinctly different for arteries and capillaries. The angioarchitecture of the newt eye differs from that of brain in that hairpin-shaped capillary loops are not observed at all.

  16. Signs of Müller cell gliotic response found in the retina of newts exposed to real and simulated microgravity

    NASA Astrophysics Data System (ADS)

    Grigoryan, E. N.; Anton, H. J.; Poplinskaya, V. A.; Aleinikova, K. S.; Domaratskaya, E. I.; Novikova, Y. P.; Almeida, E.

    2012-05-01

    The effects of real and simulated microgravity on the eye tissue regeneration of newts were investigated. For the first time changes in Müller glial cells in the retina of eyes regenerating after retinal detachment were detected in newts exposed to clinorotation. The cells divided, were hypertrophied, and their processes were thickened. Such changes suggested reactive gliosis and were more significant in animals exposed to rotation when compared with desk-top controls. Later experiments onboard the Russian biosatellite Bion-11 showed similar changes in the retinas that were regenerating in a two-week spaceflight. In the Bion-11 animals, GFAP, the major structural protein of retinal macroglial cells, was found to be upregulated. In a more recent experiment onboard Foton-M3 (2007), GFAP expression in retinas of space-flown, ground control (kept at 1 g), and basal control (sacrificed on launch day) newts was quantified, using microscopy, immunohistochemistry, and digital image analysis. A low level of immunoreactivity was observed in basal controls. In contrast, retinas of space-flown animals showed greater GFAP immunoreactivity associated with both an increased cell number and a higher thickness of intermediate filaments. This, in turn, was accompanied by up-regulation of stress protein (HSP90) and growth factor (FGF2) expressions. It can be postulated that such a response of Müller cells was to mitigate the retinal stress in newts exposed to microgravity. Taken together, the data suggest that the retinal population of macroglial cells could be sensitive to gravity changes and that in space it can react by enhancing its neuroprotective function.

  17. An Attempt at Captive Breeding of the Endangered Newt Echinotriton andersoni, from the Central Ryukyus in Japan.

    PubMed

    Igawa, Takeshi; Sugawara, Hirotaka; Tado, Miyuki; Nishitani, Takuma; Kurabayashi, Atsushi; Islam, Mohammed Mafizul; Oumi, Shohei; Katsuren, Seiki; Fujii, Tamotsu; Sumida, Masayuki

    2013-01-01

    Anderson's crocodile newt (Echinotriton andersoni) is distributed in the Central Ryukyu Islands of southern Japan, but environmental degradation and illegal collection over the last several decades have devastated the local populations. It has therefore been listed as a class B1 endangered species in the IUCN Red List, indicating that it is at high risk of extinction in the wild. The species is also protected by law in both Okinawa and Kagoshima prefectures. An artificial insemination technique using hormonal injections could not be applied to the breeding of this species in the laboratory. In this study we naturally bred the species, and tested a laboratory farming technique using several male and female E. andersoni pairs collected from Okinawa, Amami, and Tokunoshima Islands and subsequently maintained in near-biotopic breeding cages. Among 378 eggs derived from 17 females, 319 (84.4%) became normal tailbud embryos, 274 (72.5%) hatched normally, 213 (56.3%) metamorphosed normally, and 141 (37.3%) became normal two-month-old newts; in addition, 77 one- to three-year-old Tokunoshima newts and 32 Amami larvae are currently still growing normally. Over the last five breeding seasons, eggs were laid in-cage on slopes near the waterfront. Larvae were raised in nets maintained in a temperature-controlled water bath at 20 °C and fed live Tubifex. Metamorphosed newts were transferred to plastic containers containing wet sponges kept in a temperature-controlled incubator at 22.5 °C and fed a cricket diet to promote healthy growth. This is the first published report of successfully propagating an endangered species by using breeding cages in a laboratory setting for captive breeding. Our findings on the natural breeding and raising of larvae and adults are useful in breeding this endangered species and can be applied to the preservation of other similarly wild and endangered species such as E. chinhaiensis. PMID:26479528

  18. An Attempt at Captive Breeding of the Endangered Newt Echinotriton andersoni, from the Central Ryukyus in Japan.

    PubMed

    Igawa, Takeshi; Sugawara, Hirotaka; Tado, Miyuki; Nishitani, Takuma; Kurabayashi, Atsushi; Islam, Mohammed Mafizul; Oumi, Shohei; Katsuren, Seiki; Fujii, Tamotsu; Sumida, Masayuki

    2013-07-31

    Anderson's crocodile newt (Echinotriton andersoni) is distributed in the Central Ryukyu Islands of southern Japan, but environmental degradation and illegal collection over the last several decades have devastated the local populations. It has therefore been listed as a class B1 endangered species in the IUCN Red List, indicating that it is at high risk of extinction in the wild. The species is also protected by law in both Okinawa and Kagoshima prefectures. An artificial insemination technique using hormonal injections could not be applied to the breeding of this species in the laboratory. In this study we naturally bred the species, and tested a laboratory farming technique using several male and female E. andersoni pairs collected from Okinawa, Amami, and Tokunoshima Islands and subsequently maintained in near-biotopic breeding cages. Among 378 eggs derived from 17 females, 319 (84.4%) became normal tailbud embryos, 274 (72.5%) hatched normally, 213 (56.3%) metamorphosed normally, and 141 (37.3%) became normal two-month-old newts; in addition, 77 one- to three-year-old Tokunoshima newts and 32 Amami larvae are currently still growing normally. Over the last five breeding seasons, eggs were laid in-cage on slopes near the waterfront. Larvae were raised in nets maintained in a temperature-controlled water bath at 20 °C and fed live Tubifex. Metamorphosed newts were transferred to plastic containers containing wet sponges kept in a temperature-controlled incubator at 22.5 °C and fed a cricket diet to promote healthy growth. This is the first published report of successfully propagating an endangered species by using breeding cages in a laboratory setting for captive breeding. Our findings on the natural breeding and raising of larvae and adults are useful in breeding this endangered species and can be applied to the preservation of other similarly wild and endangered species such as E. chinhaiensis.

  19. Changes in the olfactory response to amino acids in Japanese newts after transfer from an aquatic to a terrestrial habitat.

    PubMed

    Inoue, Ritsuko; Nakatani, Kei

    2010-04-01

    Amphibians are capable of smelling both volatile and water-soluble (e.g., amino acids) odorants. Adult Japanese newts, Cynops pyrrhogaster, live mostly in water, except during hibernation, but sometimes on land. To examine olfactory responses of the newts to adaptation to a short-term stay on land (land adaptation), we measured the magnitude of the olfactory response at five different time points (land adaptation time: 0, 30, 54, 90, and 114 h after transfer from an aquatic to a terrestrial habitat by using electro-olfactogram (EOG) recordings. Statistical analysis by the weighted linear model (P < 0.05) indicated that the time to land adaptation had a significant effect on the magnitude of the EOG induced by 1 microM and 10 microM amino acid mixtures. Further, the slope estimates of the weighted linear model were significantly positive (P < 0.05). These results indicate that the magnitude of the EOG response to amino acid mixtures (arginine, alanine, proline, and glutamic acid) significantly increases with land adaptation time. On the other hand, we observed no significant relationship between the magnitude of the EOG response induced by an 0.05% volatile odorant mixture (isoamyl acetate, n-amyl acetate, cineole, and limonene) and land adaptation time. Our results indicate that olfactory sensitivity to amino acids significantly increases with land adaptation time in adult Japanese newts.

  20. Tetrodotoxin concentrations within a clutch and across embryonic development in eggs of the rough-skinned newts (Taricha granulosa).

    PubMed

    Gall, Brian G; Stokes, Amber N; Pett, Jory J; Spivey, Kari L; French, Susannah S; Brodie, Edmund D; Brodie, Edmund D

    2014-11-01

    Tetrodotoxin is an enigmatic neurotoxin that is found in a wide-variety of organisms. Unfortunately, tetrodotoxin (TTX) toxicity across life-history stages is poorly understood in most organisms. Rough-skinned newts (Taricha granulosa) possess the greatest known quantities of TTX of any organism and numerous studies have begun to elucidate these patterns in this species. We conducted a series of studies to answer the following questions: (1) do eggs from a single female's clutch vary in toxicity? (2) does TTX concentration change during embryonic development? and (3) does the jelly coat from newt eggs possess TTX? We found that the amount of TTX in newt eggs depended on the relative "position" of the egg within a clutch; eggs deposited at the beginning of the clutch had substantially more TTX than those at the end. During development egg toxicity remained consistent until hatching. The jelly coat contained small quantities of TTX, but these were not correlated with the toxicity of the embryo. These results clarify several long-held interpretations about embryo toxicity and continue to elucidate the life-history patterns of tetrodotoxin toxicity in this amphibian.

  1. Proteomic analysis of the skin from Chinese fire-bellied newt and comparison to Chinese giant salamander.

    PubMed

    Sun, Jingyan; Geng, Xiaofang; Guo, Jianlin; Zang, Xiayan; Li, Pengfei; Li, Deming; Xu, Cunshuan

    2016-09-01

    Animal skin that directly interfaces with the external environment has developed diverse adaptive functions to a variety of ecological conditions laden with pathogenic infection and physical harm. Amphibians exhibit various adaptations related to their "incomplete" shift from the aquatic to the terrestrial habitat. Therefore, it is very necessary to explore the molecular basis of skin function and adaptation in amphibians. Currently, the studies on the molecular mechanisms of skin functions in anuran amphibians have been reported, but in urodele amphibians are rare. This study identified the skin proteomes of Chinese fire-bellied newt Cynops orientalis by a proteomic method, and compared the results to the skin proteomes of Chinese giant salamander Andrias davidianus obtained previously. A total of 452 proteins were identified in the newt skin by MALDI-TOF/MS, and functional annotation results by DAVID analysis showed that special functions such as wound healing, immune response, defense and respiration, were significantly enriched. Comparison results showed that the two species had a great difference in the aspects of protein kinds and abundance, and the highly expressed proteins may tightly correlate with living conditions. Moreover, the newt skin might have stronger immunity, but weaker respiration than the giant salamander skin to adapt to various living environments. This research provides a molecular basis for further studies on amphibian skin function and adaptation.

  2. Proteomic analysis of the skin from Chinese fire-bellied newt and comparison to Chinese giant salamander.

    PubMed

    Sun, Jingyan; Geng, Xiaofang; Guo, Jianlin; Zang, Xiayan; Li, Pengfei; Li, Deming; Xu, Cunshuan

    2016-09-01

    Animal skin that directly interfaces with the external environment has developed diverse adaptive functions to a variety of ecological conditions laden with pathogenic infection and physical harm. Amphibians exhibit various adaptations related to their "incomplete" shift from the aquatic to the terrestrial habitat. Therefore, it is very necessary to explore the molecular basis of skin function and adaptation in amphibians. Currently, the studies on the molecular mechanisms of skin functions in anuran amphibians have been reported, but in urodele amphibians are rare. This study identified the skin proteomes of Chinese fire-bellied newt Cynops orientalis by a proteomic method, and compared the results to the skin proteomes of Chinese giant salamander Andrias davidianus obtained previously. A total of 452 proteins were identified in the newt skin by MALDI-TOF/MS, and functional annotation results by DAVID analysis showed that special functions such as wound healing, immune response, defense and respiration, were significantly enriched. Comparison results showed that the two species had a great difference in the aspects of protein kinds and abundance, and the highly expressed proteins may tightly correlate with living conditions. Moreover, the newt skin might have stronger immunity, but weaker respiration than the giant salamander skin to adapt to various living environments. This research provides a molecular basis for further studies on amphibian skin function and adaptation. PMID:27343457

  3. Interactions of an insecticide with competition and pond drying in amphibian communities

    USGS Publications Warehouse

    Boone, M.D.; Semlitsch, R.D.

    2002-01-01

    Amphibian populations are often imbedded in agricultural landscapes. Therefore the potential for contamination of their habitat is considerable. Our study examined the effects of an insecticide (carbaryl, a neurotoxin), on larval amphibian communities experiencing natural stresses of competition for resources, predation, and pond drying. In a set of experimental ponds, tadpoles of three anuran species (southern leopard frog [Rana sphenocephala], plains leopard frog [R. blairi], and the Woodhouse's toad [Bufo woodhousii]) were added to 1000-L ponds containing leaf litter, plankton, two newts (Notophthalmus viridescens), and four overwintered green frog (R. clamitans) tadpoles. We manipulated the overall tadpole density (low or high), pond hydroperiod (constant or drying), and chemical exposure (0, 3.5, 5.0, or 7.0 mg/L carbaryl) of the ponds. We measured mass, time, and survival to metamorphosis to determine treatment effects. Carbaryl positively affected Woodhouse's toad survival, although it had a negligible effect on both leopard frog species. Tadpole density interacted with the chemical treatment: Proportionately more Woodhouse's toads survived to metamorphosis in high-density environments than in low-density or control environments. Greater survival may be an indirect effect of increased algal food resources from carbaryl exposure. Most newts lost mass over the course of the experiment, although ponds with drying hydroperiods and high anuran density were the least favorable environments. Overwintered green frogs exposed to carbaryl had longer larval periods on average than did green frogs in control ponds. Our study demonstrated that even sublethal, short-lived contaminants can alter natural communities in ways that cannot be predicted from simple, one-factor studies.

  4. An Attempt at Captive Breeding of the Endangered Newt Echinotriton andersoni, from the Central Ryukyus in Japan

    PubMed Central

    Igawa, Takeshi; Sugawara, Hirotaka; Tado, Miyuki; Nishitani, Takuma; Kurabayashi, Atsushi; Islam, Mohammed Mafizul; Oumi, Shohei; Katsuren, Seiki; Fujii, Tamotsu; Sumida, Masayuki

    2013-01-01

    Simple Summary We naturally bred the endangered Anderson’s crocodile newt (Echinotriton andersoni) and tested a laboratory farming technique using near-biotopic breeding cages with several male and female pairs collected from Okinawa, Amami, and Tokunoshima Islands. This is the first published report of successfully propagating an endangered species by using breeding cages in a laboratory setting for captive breeding. Our findings on the natural breeding and raising of larvae and adults are useful in breeding this endangered species, and can be applied to the preservation of other similarly wild and endangered species. Abstract Anderson’s crocodile newt (Echinotriton andersoni) is distributed in the Central Ryukyu Islands of southern Japan, but environmental degradation and illegal collection over the last several decades have devastated the local populations. It has therefore been listed as a class B1 endangered species in the IUCN Red List, indicating that it is at high risk of extinction in the wild. The species is also protected by law in both Okinawa and Kagoshima prefectures. An artificial insemination technique using hormonal injections could not be applied to the breeding of this species in the laboratory. In this study we naturally bred the species, and tested a laboratory farming technique using several male and female E. andersoni pairs collected from Okinawa, Amami, and Tokunoshima Islands and subsequently maintained in near-biotopic breeding cages. Among 378 eggs derived from 17 females, 319 (84.4%) became normal tailbud embryos, 274 (72.5%) hatched normally, 213 (56.3%) metamorphosed normally, and 141 (37.3%) became normal two-month-old newts; in addition, 77 one- to three-year-old Tokunoshima newts and 32 Amami larvae are currently still growing normally. Over the last five breeding seasons, eggs were laid in-cage on slopes near the waterfront. Larvae were raised in nets maintained in a temperature-controlled water bath at 20 °C and fed live

  5. Müller cell gliotic response in the retina of the newts exposed to real and simulated microgravity

    NASA Astrophysics Data System (ADS)

    Grigoryan, Eleonora N.; Poplinskaya, Valentina; Domaratskaya; Aleinikova, Karina; Novikova, Julia; Anton, Hermann J.; Almeida, Eduardo

    The effects of real and simulated microgravity on the eye tissue regeneration of newts (Pl. waltli) after lens and/or retina removal were investigated. Changes in Müller glial cells in the retina of eyes regenerating after lens extirpation were detected in newts exposed to clinostat-ing. The cells were hypertrophied, and their processes thickened. Such changes were viewed as specific of reactive gliosis [1]. Later experiments onboard the Russian biosatellite Bion-11 showed similar changes in the retinas of newts regenerating after a two-week spaceflight. In the Bion-11 animals, GFAP, the major structural protein of macroglial cells was found to be up-regulated [2]. In more recent experiments onboard Foton-2 (2005) and Foton-M3 (2007), GFAP expression in retinas of space-flown, ground control (kept at 1 g), and basal control (sacrificed on launch day) newts was quantified, using microscopy, immunohistochemistry, and digital image analysis. It was found that Müller cell processes of non-operated animals dis-u played low GFAP immunolabeling. A low level of immunoreactivity was also observed in basal controls. In contrast, retinas of space-flown animals showed greater GFAP immunoreactivity associated with both an increased cell number and a higher density of intermediate filaments [3]. This, in turn, was accompanied by up-regulation of stress protein (HSP90) and growth factor (FGF2) expressions. It can be postulated that such a response of Müller cells was to mitigate the retinal stress in newts exposed to microgravity. Although the exact mechanisms remain unknown, it can be hypothesized that GFAP up-regulation is mediated by HSPs and growth factors, particularly by FGF2. Taken together, these data suggest that the retinal population of macroglial cells is sensitive to gravity changes and that in space it can react by enhancing its neuroprotective function. [1] Grigoryan E.N., Anton H.J., Mitashov V.I. Adv. Space Res. 1998. V. 22. N.2. P. 293-301. [2] Grigoryan E

  6. Musculoskeletal architecture of the prey capture apparatus in salamandrid newts with multiphasic lifestyle: does anatomy change during the seasonal habitat switches?

    PubMed

    Heiss, Egon; Handschuh, Stephan; Aerts, Peter; Van Wassenbergh, Sam

    2016-05-01

    Some newt species change seasonally between an aquatic and a terrestrial life as adults, and are therefore repeatedly faced with different physical circumstances that affect a wide range of functions of the organism. For example, it has been observed that seasonally habitat-changing newts display notable changes in skin texture and tail fin anatomy, allowing one to distinguish an aquatic and a terrestrial morphotype. One of the main functional challenges is the switch between efficient aquatic and terrestrial prey capture modes. Recent studies have shown that newts adapt quickly by showing a high degree of behavioral flexibility, using suction feeding in their aquatic stage and tongue prehension in their terrestrial stage. As suction feeding and tongue prehension place different functional demands on the prey capture apparatus, this behavioral flexibility may clearly benefit from an associated morphological plasticity. In this study, we provide a detailed morphological analysis of the musculoskeletal system of the prey capture apparatus in the two multiphasic newt species Ichthyosaura alpestris and Lissotriton vulgaris by using histological sections and micro-computed tomography. We then test for quantitative changes of the hyobranchial musculoskeletal system between aquatic and terrestrial morphotypes, The descriptive morphology of the cranio-cervical musculoskeletal system provides new insights on form and function of the prey capture apparatus in newts, and the quantitative approach shows hypertrophy of the hyolingual musculoskeletal system in the terrestrial morphotype of L. vulgaris but hypertrophy in the aquatic morphotype of I. alpestris. It was therefore concluded that the seasonal habitat shifts are accompanied by a species-dependent muscular plasticity of which the potential effect on multiphasic feeding performance in newts remains unclear. PMID:26892189

  7. 7alpha-Hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts by means of the dopaminergic system.

    PubMed

    Matsunaga, Masahiro; Ukena, Kazuyoshi; Baulieu, Etienne-Emile; Tsutsui, Kazuyoshi

    2004-12-01

    It is becoming clear that steroids can be synthesized de novo by the brain and other nervous systems. Such steroids are called neurosteroids, and de novo neurosteroidogenesis from cholesterol is a conserved property of vertebrate brains. In this study, we show that the newt brain actively produces 7alpha-hydroxypregnenolone, a previously undescribed amphibian neurosteroid that stimulates locomotor activity. 7alpha-hydroxypregnenolone was identified as a most abundant amphibian neurosteroid in the newt brain by using biochemical techniques combined with HPLC, TLC, and GC-MS analyses. The production of 7alpha-hydroxypregnenolone in the diencephalon and rhombencephalon was higher than that in the telencephalon and peripheral steroidogenic glands. In addition, 7alpha-hydroxypregnenolone synthesis in the brain showed marked changes during the annual breeding cycle, with a maximal level in the spring breeding period when locomotor activity of the newt increases. Behavioral analysis of newts in the nonbreeding period demonstrated that administration of this previously undescribed amphibian neurosteroid acutely increased locomotor activity. In vitro analysis further revealed that 7alpha-hydroxypregnenolone treatment resulted in a dose-dependent increase in the release of dopamine from cultured brain tissue of nonbreeding newts. The effect of this neurosteroid on locomotion also was abolished by dopamine D(2)-like receptor antagonists. These results indicate that 7alpha-hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts through the dopaminergic system. This study demonstrates a physiological function of 7alpha-hydroxypregnenolone that has not been described previously in any vertebrate class. This study also provides findings on the regulatory mechanism of locomotor activity from a unique standpoint.

  8. Musculoskeletal architecture of the prey capture apparatus in salamandrid newts with multiphasic lifestyle: does anatomy change during the seasonal habitat switches?

    PubMed

    Heiss, Egon; Handschuh, Stephan; Aerts, Peter; Van Wassenbergh, Sam

    2016-05-01

    Some newt species change seasonally between an aquatic and a terrestrial life as adults, and are therefore repeatedly faced with different physical circumstances that affect a wide range of functions of the organism. For example, it has been observed that seasonally habitat-changing newts display notable changes in skin texture and tail fin anatomy, allowing one to distinguish an aquatic and a terrestrial morphotype. One of the main functional challenges is the switch between efficient aquatic and terrestrial prey capture modes. Recent studies have shown that newts adapt quickly by showing a high degree of behavioral flexibility, using suction feeding in their aquatic stage and tongue prehension in their terrestrial stage. As suction feeding and tongue prehension place different functional demands on the prey capture apparatus, this behavioral flexibility may clearly benefit from an associated morphological plasticity. In this study, we provide a detailed morphological analysis of the musculoskeletal system of the prey capture apparatus in the two multiphasic newt species Ichthyosaura alpestris and Lissotriton vulgaris by using histological sections and micro-computed tomography. We then test for quantitative changes of the hyobranchial musculoskeletal system between aquatic and terrestrial morphotypes, The descriptive morphology of the cranio-cervical musculoskeletal system provides new insights on form and function of the prey capture apparatus in newts, and the quantitative approach shows hypertrophy of the hyolingual musculoskeletal system in the terrestrial morphotype of L. vulgaris but hypertrophy in the aquatic morphotype of I. alpestris. It was therefore concluded that the seasonal habitat shifts are accompanied by a species-dependent muscular plasticity of which the potential effect on multiphasic feeding performance in newts remains unclear.

  9. Information-content of morphological and behavioural sexual traits in the Palmate newt (Lissotriton helveticus).

    PubMed

    Cornuau, Jérémie H; Schmeller, Dirk S; Pigeault, Romain; Sibeaux, Adelaïde; Tourat, Audrey; Loyau, Adeline

    2014-10-01

    The question of why females evaluate more than one sexual trait to choose their mates has received increasing attention in recent years. Here, we investigated the information-content of both morphological and behavioural sexual traits that have been identified as predictors of male reproductive success in the palmate newt, Lissotriton helveticus. We examined the co-variation of multiple traits with one aspect of male quality, the male body condition, using both a correlative study and an experimental diet restriction. We found that the development of the three morphological sexual traits (filament length, hind-foot-web size, and crest size) was positively inter-correlated, and was correlated to body condition. In contrast, courtship activity, an important indicator for male reproductive success, was uncorrelated to male body condition. Our results suggest that females likely obtain redundant information on male condition when evaluating filament length, hind-foot-web size and crest size during mate choice. Contrary to our expectations, display activity was not a reliable indicator of male condition, leaving the information-content of this trait unraveled. Our results further suggest that complex, multiple traits may evolve because redundant message, unreliable signals and, possibly, multiple messages can coexist. PMID:25241307

  10. Divergence history of the Carpathian and smooth newts modelled in space and time.

    PubMed

    Zieliński, P; Nadachowska-Brzyska, K; Dudek, K; Babik, W

    2016-08-01

    Information about demographic history is essential for the understanding of the processes of divergence and speciation. Patterns of genetic variation within and between closely related species provide insights into the history of their interactions. Here, we investigated historical demography and genetic exchange between the Carpathian (Lissotriton montandoni, Lm) and smooth (L. vulgaris, Lv) newts. We combine an extensive geographical sampling and multilocus nuclear sequence data with the approximate Bayesian computation framework to test alternative scenarios of divergence and reconstruct the temporal and spatial pattern of gene flow between species. A model of recent (last glacial period) interspecific gene flow was favoured over alternative models. Thus, despite the relatively old divergence (4-6 mya) and presumably long periods of isolation, the species have retained the ability to exchange genes. Nevertheless, the low migration rates (ca. 10(-6) per gene copy per generation) are consistent with strong reproductive isolation between the species. Models allowing demographic changes were favoured, suggesting that the effective population sizes of both species at least doubled as divergence reaching the current ca. 0.2 million in Lm and 1 million in Lv. We found asymmetry in rates of interspecific gene flow between Lm and one evolutionary lineage of Lv. We suggest that intraspecific polymorphism for hybrid incompatibilities segregating within Lv could explain this pattern and propose further tests to distinguish between alternative explanations. Our study highlights the importance of incorporating intraspecific genetic structure into the models investigating the history of divergence. PMID:27288862

  11. Genomic heterogeneity of historical gene flow between two species of newts inferred from transcriptome data.

    PubMed

    Stuglik, Michał T; Babik, Wiesław

    2016-07-01

    The role of gene flow in species formation is a major unresolved issue in speciation biology. Progress in this area requires information on the long-term patterns of gene flow between diverging species. Here, we used thousands of single-nucleotide polymorphisms derived from transcriptome resequencing and a method modeling the joint frequency spectrum of these polymorphisms to reconstruct patterns of historical gene flow between two Lissotriton newts: L. vulgaris (Lv) and L. montandoni (Lm). We tested several models of divergence including complete isolation and various scenarios of historical gene flow. The model of secondary contact received the highest support. According to this model, the species split from their common ancestor ca. 5.5 million years (MY) ago, evolved in isolation for ca. 2 MY, and have been exchanging genes for the last 3.5 MY Demographic changes have been inferred in both species, with the current effective population size of ca. 0.7 million in Lv and 0.2 million in Lm. The postdivergence gene flow resulted in two-directional introgression which affected the genomes of both species, but was more pronounced from Lv to Lm. Interestingly, we found evidence for genomic heterogeneity of interspecific gene flow. This study demonstrates the complexity of long-term gene flow between distinct but incompletely reproductively isolated taxa which divergence was initiated millions of years ago. PMID:27386093

  12. The epidermal melanocyte population in the skin of ultraviolet-irradiated crested newt

    SciTech Connect

    Losa, M.; Zavanella, T.; Milani, S.

    1982-02-01

    The response of the epidermal melanocyte population to repeated ultraviolet (UV) exposure (wavelength spectrum 275-350 nm) has been investigated in the crested newt, Triturus cristatus carnifex. The effects of different doses of UV light were studied. The animals were killed 7 months after the first UV exposure. Only a slight decrease in the number of pigment cells was found after 85 sequential irradiations with a total dose of 1.3 x 10(5) J/m2, whereas striking decreases were observed when the same total dose was fractionated into 14 exposures or when a double dose was given in 57 exposures. The relationship between the square roots of the epidermal melanocyte densities and single doses appeared to be roughly linear, at least over the range of doses administered. The main factor in melanocyte damage seemed to be the single dose of irradiation rather than the cumulative dose administered. Decreased melanin content of the keratinocytes was observed in most irradiated animals.

  13. Relatedness, body size and paternity in the alpine newt, Triturus alpestris.

    PubMed

    Garner, Trenton W J; Schmidt, Benedikt R

    2003-03-22

    Sexual selection has traditionally been investigated assuming that male quality is as skewed as patterns of male reproductive success can sometimes be. Recently, female choice has been investigated under the model of genetic compatibility, which assumes that each individual female has her own 'best' mate and there is no overall optimal choice for all females. We investigated female mate choice in the newt species Triturus alpestris, a member of a genus where female choice has been investigated only within the context of the optimal male (female choice for condition-dependent traits). We provided females with two males that differed in one condition-dependent trait (body size) and overall genetic composition. Both male body size and female body size did not influence paternity, but the degree of genetic relatedness between females and potential mates did. Two components of fitness (fecundity and hatching success) did not differ between singly and multiply sired clutches, indicating that females do not employ polyandry as a means of increasing offspring fitness through genetic bet-hedging. Instead, we hypothesize that females may mate initially for fertility assurance, but prefer less-related males as the most genetically compatible mates. PMID:12769462

  14. The distribution and taxonomy of Lissotriton newts in Turkey (Amphibia, Salamandridae).

    PubMed

    Wielstra, Ben; Bozkurt, Emin; Olgun, Kurtuluş

    2015-01-01

    Two and perhaps three taxa of Lissotriton newt occur in Turkey. Their species status is controversial. The distribution of these taxa and the taxonomic status of each are reviewed and discussed. A database of 128 Turkish Lissotriton localities was compiled and species distribution models were constructed. We reiterate that the presence of Lissotriton (vulgaris) lantzi in Turkey is disputed and needs confirmation. The range of Lissotriton (vulgaris) kosswigi is restricted to north-western Anatolia - given the small global range of this Turkey endemic, a closer look at its conservation status is warranted. The distribution of Lissotritonvulgarisschmidtleri covers western Asiatic and European Turkey. The findings support an allopatric distribution of the Turkish Lissotriton species. We reflect on the biological significance of previously reported morphological intermediates between Lissotriton (vulgaris) kosswigi and Lissotritonvulgarisschmidtleri in the light of the recent proposal to recognize kosswigi at the species level. The available data are in line with species status for Lissotriton (vulgaris) lantzi and Lissotriton (vulgaris) kosswigi. Although Lissotritonvulgarisschmidtleri is a genetically diverged taxon as well, the extent of gene flow with parapatric European Lissotriton taxa is as yet unknown.

  15. Chronic Exposure to Cadmium Disrupts the Adrenal Gland Activity of the Newt Triturus carnifex (Amphibia, Urodela)

    PubMed Central

    Gay, Flaminia; Laforgia, Vincenza; Caputo, Ivana; Esposito, Carla; Lepretti, Marilena

    2013-01-01

    We intended to verify the safety of the freshwater values established for cadmium by the European Community and the Italian Ministry of Health in drinking water (5 μg/L) and sewage waters (20 μg/L). Therefore, we chronically exposed the newt Triturus carnifex to 5 μg/L and 20 μg/L doses of cadmium, respectively, during 3 and 9 months and verified the effects on the adrenal gland. We evaluated the serum concentrations of adrenocorticotropic hormone (ACTH), corticosterone, aldosterone, norepinephrine, and epinephrine. During the 3-month exposure, both doses of cadmium decreased ACTH and corticosterone serum levels and increased aldosterone and epinephrine serum levels. During the 9-month exposure, the 5 μg/L dose decreased ACTH and increased aldosterone and epinephrine serum levels; the 20 μg/L dose decreased norepinephrine and epinephrine serum levels, without affecting the other hormones. It was concluded that (1) chronic exposure to the safety values established for cadmium disrupted the adrenal gland activity and (2) the effects of cadmium were related both to the length of exposure and the dose administered. Moreover, our results suggest probable risks to human health, due to the use of water contaminated by cadmium. PMID:23971036

  16. Divergence history of the Carpathian and smooth newts modelled in space and time.

    PubMed

    Zieliński, P; Nadachowska-Brzyska, K; Dudek, K; Babik, W

    2016-08-01

    Information about demographic history is essential for the understanding of the processes of divergence and speciation. Patterns of genetic variation within and between closely related species provide insights into the history of their interactions. Here, we investigated historical demography and genetic exchange between the Carpathian (Lissotriton montandoni, Lm) and smooth (L. vulgaris, Lv) newts. We combine an extensive geographical sampling and multilocus nuclear sequence data with the approximate Bayesian computation framework to test alternative scenarios of divergence and reconstruct the temporal and spatial pattern of gene flow between species. A model of recent (last glacial period) interspecific gene flow was favoured over alternative models. Thus, despite the relatively old divergence (4-6 mya) and presumably long periods of isolation, the species have retained the ability to exchange genes. Nevertheless, the low migration rates (ca. 10(-6) per gene copy per generation) are consistent with strong reproductive isolation between the species. Models allowing demographic changes were favoured, suggesting that the effective population sizes of both species at least doubled as divergence reaching the current ca. 0.2 million in Lm and 1 million in Lv. We found asymmetry in rates of interspecific gene flow between Lm and one evolutionary lineage of Lv. We suggest that intraspecific polymorphism for hybrid incompatibilities segregating within Lv could explain this pattern and propose further tests to distinguish between alternative explanations. Our study highlights the importance of incorporating intraspecific genetic structure into the models investigating the history of divergence.

  17. Genomic heterogeneity of historical gene flow between two species of newts inferred from transcriptome data.

    PubMed

    Stuglik, Michał T; Babik, Wiesław

    2016-07-01

    The role of gene flow in species formation is a major unresolved issue in speciation biology. Progress in this area requires information on the long-term patterns of gene flow between diverging species. Here, we used thousands of single-nucleotide polymorphisms derived from transcriptome resequencing and a method modeling the joint frequency spectrum of these polymorphisms to reconstruct patterns of historical gene flow between two Lissotriton newts: L. vulgaris (Lv) and L. montandoni (Lm). We tested several models of divergence including complete isolation and various scenarios of historical gene flow. The model of secondary contact received the highest support. According to this model, the species split from their common ancestor ca. 5.5 million years (MY) ago, evolved in isolation for ca. 2 MY, and have been exchanging genes for the last 3.5 MY Demographic changes have been inferred in both species, with the current effective population size of ca. 0.7 million in Lv and 0.2 million in Lm. The postdivergence gene flow resulted in two-directional introgression which affected the genomes of both species, but was more pronounced from Lv to Lm. Interestingly, we found evidence for genomic heterogeneity of interspecific gene flow. This study demonstrates the complexity of long-term gene flow between distinct but incompletely reproductively isolated taxa which divergence was initiated millions of years ago.

  18. Information-content of morphological and behavioural sexual traits in the Palmate newt (Lissotriton helveticus).

    PubMed

    Cornuau, Jérémie H; Schmeller, Dirk S; Pigeault, Romain; Sibeaux, Adelaïde; Tourat, Audrey; Loyau, Adeline

    2014-10-01

    The question of why females evaluate more than one sexual trait to choose their mates has received increasing attention in recent years. Here, we investigated the information-content of both morphological and behavioural sexual traits that have been identified as predictors of male reproductive success in the palmate newt, Lissotriton helveticus. We examined the co-variation of multiple traits with one aspect of male quality, the male body condition, using both a correlative study and an experimental diet restriction. We found that the development of the three morphological sexual traits (filament length, hind-foot-web size, and crest size) was positively inter-correlated, and was correlated to body condition. In contrast, courtship activity, an important indicator for male reproductive success, was uncorrelated to male body condition. Our results suggest that females likely obtain redundant information on male condition when evaluating filament length, hind-foot-web size and crest size during mate choice. Contrary to our expectations, display activity was not a reliable indicator of male condition, leaving the information-content of this trait unraveled. Our results further suggest that complex, multiple traits may evolve because redundant message, unreliable signals and, possibly, multiple messages can coexist.

  19. Axon regeneration across the site of injury in the optic nerve of the newt Triturus pyrrhogaster.

    PubMed

    Stensaas, L J; Feringa, E R

    1977-04-29

    The process by which axons regenerate following a freeze injury to the optic nerve of the newt was analyzed by light and electron microscopy. Freezing destroys cellular constituents in a one millimeter segment of the nerve, leaving intact the basal lamina and the blood supply to the eye. No axons are seen at the site of injury one to seven days post lesion. This contrasts with the persistence of normal-appearing but severed unmyelinated axons within the cranial stump which thus give a false appearance of early regeneration. The first axon sprouts traverse the lesion and enter the cranial strump by ten days. The number of regenerating axons increases rapidly thereafter with no signs of random growth at the site of injury. These axon sprouts tend to be somewhat larger than normal unmyelinated axons and contain dense core vesicles and abnormal organelles similar to those in growing axons in tissue culture. The persisting basal lamina inside the optic sheath appears to provide continuity across the site of injury, to orient axon sprouts, and to favor an orderly process of axon regeneration without neuroma formation.

  20. Chronic transplantation immunity in newts: temperature susceptibility of an effector phase in allo-skin graft rejection.

    PubMed

    Kinefuchi, Kenjiroh; Kushida, Yoshihiro; Johnouchi, Masato; Shimizu, Yuiko; Ohneda, Hikaru; Fujii, Masato; Hosono, Masamichi

    2011-07-01

    Urodele amphibians are unique due to their greatly reduced immune responsiveness compared to bony fishes, which show acute immune responsiveness. In newts, the mean survival time of allogenic skin grafts in the transplantation immunity was 48.8 ± 8.3 days at 25°C, suggesting that it occurs in a chronic manner. The graft rejection process was categorized into three stages: a latent stage with frequent blood circulation, or the immune induction phase; a vascular stoppage stage with dominant infiltrating cells of T cells; and a rejection stage showing the change of the dominant cells to monocytes/macrophages, probably as effector cells, tetntatively referred to as the immune effector phase. The immune induction phase is susceptible to the cyclophosphamide (CY) mitosis inhibitor, but not to a temperature shift from 18 to 27°C, while the immune effector phase is susceptible to temperature shifts, but not CY-treatment, although the temperature shift failed to shorten the graft survival time to less than 25 days, which nearly equals that of the secondary set of grafts where the lack of complete blood circulation is remarkable and graft rejection is resistant to CY-treatment. In contrast, a very low temperature (5-10°C) completely prevented effector generation in newts; in frogs, however, it is reported that such low temperatures did not prevent the generation of effectors. Taken together, these data suggest that chronic responses in newts are due to effector cells other than cytotoxic T cells; possible effector cells are discussed.

  1. Possible hormonal interaction for eliciting courtship behavior in the male newt, Cynops pyrrhogaster.

    PubMed

    Toyoda, Fumiyo; Hasunuma, Itaru; Nakada, Tomoaki; Haraguchi, Shogo; Tsutsui, Kazuyoshi; Kikuyama, Sakae

    2015-12-01

    Reproductive behavior in amphibians, as in other vertebrate animals, is under the control of multiple hormonal substances. Prolactin (PRL), arginine vasotocin (AVT), androgen, and 7α-hydroxypregnenolone (7α-OH PREG), four such substances with hormonal activity, are known to be involved in the expression of the tail vibration behavior which is the initial step of courtship performed by the male newt, Cynops pyrrhogaster. As current information on the interaction(s) between these hormones in terms of eliciting tail vibration behavior is limited, we have investigated whether the decline of expression of tail vibration behavior due to suppression of the activity of any one of these hormones can be restored by supplying any one of the other three hormones exogenously. Expression of the behavior was determined in terms of incidence (% of test animals exhibiting the behavior) and frequency (number of times that the behavior was repeated during the test period). Neither PRL nor androgen restored the decline in the incidence and frequency of the tail vibration behavior caused by the suppression of the activity of any one of other three hormones. AVT completely restored both the anti-PRL antibody-induced and flutamide (an androgen receptor antagonist)-induced, but not ketoconazole (an inhibitor of the steroidogenic CYP enzymes)-induced decline in the incidence and frequency of the tail vibration behavior. The neurosteroid, 7α-OH PREG, failed to restore flutamide-induced decline in the incidence and frequency of the behavior. However, it was able to restore both anti-PRL antibody-induced and AVT receptor antagonist-induced decline in the incidence, but not in the frequency of the behavior. In another experiment designed to see the activity of hormones enhancing the frequency of the tail vibration behavior, AVT was revealed to be more potent than 7α-OH PREG. The role of each hormonal substance in determining the expression of the tail vibration behavior was discussed based

  2. Homeotic transformations and number changes in the vertebral column of Triturus newts.

    PubMed

    Slijepčević, Maja; Galis, Frietson; Arntzen, Jan W; Ivanović, Ana

    2015-01-01

    We explored intraspecific variation in vertebral formulae, more specifically the variation in the number of thoracic vertebrae and frequencies of transitional sacral vertebrae in Triturus newts (Caudata: Salamandridae). Within salamandrid salamanders this monophyletic group shows the highest disparity in the number of thoracic vertebrae and considerable intraspecific variation in the number of thoracic vertebrae. Triturus species also differ in their ecological preferences, from predominantly terrestrial to largely aquatic. Following Geoffroy St. Hilaire's and Darwin's rule which states that structures with a large number of serially homologous repetitive elements are more variable than structures with smaller numbers, we hypothesized that the variation in vertebral formulae increases in more elongated species with a larger number of thoracic vertebrae. We furthermore hypothesized that the frequency of transitional vertebrae will be correlated with the variation in the number of thoracic vertebrae within the species. We also investigated potential effects of species hybridization on the vertebral formula. The proportion of individuals with a number of thoracic vertebrae different from the modal number and the range of variation in number of vertebrae significantly increased in species with a larger number of thoracic vertebrae. Contrary to our expectation, the frequencies of transitional vertebrae were not correlated with frequencies of change in the complete vertebrae number. The frequency of transitional sacral vertebra in hybrids did not significantly differ from that of the parental species. Such a pattern could be a result of selection pressure against transitional vertebrae and/or a bias towards the development of full vertebrae numbers. Although our data indicate relaxed selection for vertebral count changes in more elongated, aquatic species, more data on different selective pressures in species with different numbers of vertebrae in the two contrasting

  3. Homeotic transformations and number changes in the vertebral column of Triturus newts

    PubMed Central

    Slijepčević, Maja; Galis, Frietson; Arntzen, Jan W.

    2015-01-01

    We explored intraspecific variation in vertebral formulae, more specifically the variation in the number of thoracic vertebrae and frequencies of transitional sacral vertebrae in Triturus newts (Caudata: Salamandridae). Within salamandrid salamanders this monophyletic group shows the highest disparity in the number of thoracic vertebrae and considerable intraspecific variation in the number of thoracic vertebrae. Triturus species also differ in their ecological preferences, from predominantly terrestrial to largely aquatic. Following Geoffroy St. Hilaire’s and Darwin’s rule which states that structures with a large number of serially homologous repetitive elements are more variable than structures with smaller numbers, we hypothesized that the variation in vertebral formulae increases in more elongated species with a larger number of thoracic vertebrae. We furthermore hypothesized that the frequency of transitional vertebrae will be correlated with the variation in the number of thoracic vertebrae within the species. We also investigated potential effects of species hybridization on the vertebral formula. The proportion of individuals with a number of thoracic vertebrae different from the modal number and the range of variation in number of vertebrae significantly increased in species with a larger number of thoracic vertebrae. Contrary to our expectation, the frequencies of transitional vertebrae were not correlated with frequencies of change in the complete vertebrae number. The frequency of transitional sacral vertebra in hybrids did not significantly differ from that of the parental species. Such a pattern could be a result of selection pressure against transitional vertebrae and/or a bias towards the development of full vertebrae numbers. Although our data indicate relaxed selection for vertebral count changes in more elongated, aquatic species, more data on different selective pressures in species with different numbers of vertebrae in the two contrasting

  4. Behavior of hindbrain neurons during the transition from rest to evoked locomotion in a newt.

    PubMed

    Bar-Gad, I; Kagan, I; Shik, M L

    1999-01-01

    Trains of electrical stimuli were delivered to the mesencephalic 'locomotor region' in the rough skin newt. The current (3-12 mcA) and the interstimulus interval (100 to 200 ms) were adjusted so that locomotion arose in approximately 10 s, or so that the train remained subthreshold for initiation of locomotion. Impulses of single neurons in the hindbrain were recorded during the transition period from rest to locomotion. Time-locked synaptic responses were bi- or unimodal with typical latencies close to 18, 23 or 28 ms, and weak irregular mode near 13 ms. Impulses that were not locked to the stimuli arose in some silent neurons, and the rate of firing of neurons with background discharge was sometimes enhanced. Composite responses consisted of both time-locked component and impulses distributed throughout the interstimulus interval. The data suggest that short-lived, wave-like propagation of the input volley ceases or is transformed into asynchronous activity after three or four translations. The latter variant could occur if the train reached the threshold for initiation of locomotion. The asynchronous activity persisted throughout interstimulus interval and could coexist with time-locked impulses. Some neurons generated only a few impulses, while others remained active from beginning to end of the train. These active neurons could either spike at a steady rate, or decrement or augment their rate of firing during the train. The time course of their activity was related to the initial rate of firing. The augmenting type of firing in a subset of neurons may arise due to the interaction of neurons with unstable, steady state and decrementing activity.

  5. Interspecific hybridization increases MHC class II diversity in two sister species of newts.

    PubMed

    Nadachowska-Brzyska, Krystyna; Zieliński, Piotr; Radwan, Jacek; Babik, Wiesław

    2012-02-01

    Our understanding of the evolutionary mechanisms generating variation within the highly polymorphic major histocompatibility complex (MHC) genes remains incomplete. Assessing MHC variation across multiple populations, of recent and ancient divergence, may facilitate understanding of geographical and temporal aspects of variation. Here, we applied 454 sequencing to perform a large-scale, comprehensive analysis of MHC class II in the closely related, hybridizing newts, Lissotriton vulgaris (Lv) and Lissotriton montandoni (Lm). Our study revealed an extensive (299 alleles) geographically structured polymorphism. Populations at the southern margin of the Lv distribution, inhabited by old and distinct lineages (southern Lv), exhibited moderate MHC variation and strong population structure, indicating little gene flow or extensive local adaptation. Lissotriton vulgaris in central Europe and the northern Balkans (northern Lv) and almost all Lm populations had a high MHC variation. A much higher proportion of MHC alleles was shared between Lm and northern Lv than between Lm and southern Lv. Strikingly, the average pairwise F(ST) between northern Lv and Lm was significantly lower than between northern and southern Lv for MHC, but not for microsatellites. Thus, high MHC variation in Lm and northern Lv may result from gene flow between species. We hypothesize that the interspecific exchange of MHC genes may be facilitated by frequency-dependent selection. A marginally significant correlation between the MHC and microsatellite allelic richness indicates that demographic factors may have contributed to the present-day pattern of MHC variation, but unequivocal signatures of adaptive evolution in MHC class II sequences emphasize the role of selection on a longer timescale.

  6. Injury, nerve, and wound epidermis related electrophoretic and fluorographic protein patterns in forelimbs of adult newts

    SciTech Connect

    Garling, D.J.; Tassava, R.A.

    1984-08-01

    Polyacrylamide slab gel electrophoresis and (/sup 35/S)methionine fluorography were used to examine proteins in regenerating newt limbs, amputated denervated limbs, unamputated denervated limbs, and separated blastema mesodermal core and wound epidermis. A total of 27 protein electrophoretic bands were obtained from amputated limbs and 24 bands from unamputated limbs. Amputation resulted in the appearance of 4 new bands and the loss of 1 band as compared to unamputated limbs. These 5 banding differences were apparent on stained gels 3 days postamputation and were maintained through 10 weeks postamputation (complete regenerate stage). Only one band in unamputated limbs was always detectable on fluorographs, whereas virtually all of the stainable bands of amputated limbs were visible on fluorographs. Amputation clearly stimulated a marked, generalized increase in the synthesis of limb proteins. The 5 amputation induced changes were equally evident in stained gels of both innervated and denervated limbs. Amputated denervated limbs possessed a full set of fluorographic bands (including the 5 differences) through 18 days postamputation. However, denervation without amputation was not sufficient to alter the stainable banding pattern. Wound epidermis and mesodermal core both displayed the 5 banding differences and had identical banding patterns with the exception of one epidermal specific band. This band was also present in whole limb skin but was absent in unamputated mesodermal limb tissue. This was the only band of unamputated limbs that was consistently detectable by fluorography. It is concluded that amputation induces nerve independent changes in protein synthesis that are common to both mesodermal core and wound epidermis. These changes may represent preparation for cellular proliferation.

  7. Homeotic transformations and number changes in the vertebral column of Triturus newts.

    PubMed

    Slijepčević, Maja; Galis, Frietson; Arntzen, Jan W; Ivanović, Ana

    2015-01-01

    We explored intraspecific variation in vertebral formulae, more specifically the variation in the number of thoracic vertebrae and frequencies of transitional sacral vertebrae in Triturus newts (Caudata: Salamandridae). Within salamandrid salamanders this monophyletic group shows the highest disparity in the number of thoracic vertebrae and considerable intraspecific variation in the number of thoracic vertebrae. Triturus species also differ in their ecological preferences, from predominantly terrestrial to largely aquatic. Following Geoffroy St. Hilaire's and Darwin's rule which states that structures with a large number of serially homologous repetitive elements are more variable than structures with smaller numbers, we hypothesized that the variation in vertebral formulae increases in more elongated species with a larger number of thoracic vertebrae. We furthermore hypothesized that the frequency of transitional vertebrae will be correlated with the variation in the number of thoracic vertebrae within the species. We also investigated potential effects of species hybridization on the vertebral formula. The proportion of individuals with a number of thoracic vertebrae different from the modal number and the range of variation in number of vertebrae significantly increased in species with a larger number of thoracic vertebrae. Contrary to our expectation, the frequencies of transitional vertebrae were not correlated with frequencies of change in the complete vertebrae number. The frequency of transitional sacral vertebra in hybrids did not significantly differ from that of the parental species. Such a pattern could be a result of selection pressure against transitional vertebrae and/or a bias towards the development of full vertebrae numbers. Although our data indicate relaxed selection for vertebral count changes in more elongated, aquatic species, more data on different selective pressures in species with different numbers of vertebrae in the two contrasting

  8. One Species, Three Pleistocene Evolutionary Histories: Phylogeography of the Italian Crested Newt, Triturus carnifex

    PubMed Central

    Canestrelli, Daniele; Salvi, Daniele; Maura, Michela; Bologna, Marco A.; Nascetti, Giuseppe

    2012-01-01

    Phylogeographic patterns of temperate species from the Mediterranean peninsulas have been investigated intensively. Nevertheless, as more phylogeographies become available, either unique patterns or new lines of concordance continue to emerge, providing new insights on the evolution of regional biotas. Here, we investigated the phylogeography and evolutionary history of the Italian crested newt, Triturus carnifex, through phylogenetic, molecular dating and population structure analyses of two mitochondrial gene fragments (ND2 and ND4; overall 1273 bp). We found three main mtDNA lineages having parapatric distribution and estimated divergence times between Late Pliocene and Early Pleistocene. One lineage (S) was widespread south of the northern Apennine chain and was further geographically structured into five sublineages, likely of Middle Pleistocene origin. The second lineage (C) was widespread throughout the Padano–Venetian plain and did not show a clear phylogeographic structure. The third lineage (N) was observed in only two populations located on western Croatia/Slovenia. Results of analysis of molecular variance suggested that partitioning populations according to the geographic distribution of these lineages and sublineages explains 76% of the observed genetic variation. The phylogeographic structure observed within T. carnifex and divergence time estimates among its lineages, suggest that responses to Pleistocene environmental changes in this single species have been as diverse as those found previously among several codistributed temperate species combined. Consistent with the landscape heterogeneity, physiographic features, and palaeogeographical evolution of its distribution range, these responses encompass multiple refugia along the Apennine chain, lowland refugia in large peri-coastal plains, and a ‘cryptic’ northern refugium. PMID:22848590

  9. The potential function of prohibitin during spermatogenesis in Chinese fire-bellied newt Cynops orientalis.

    PubMed

    Jin, Jia-Min; Hou, Cong-Cong; Tan, Fu-Qing; Yang, Wan-Xi

    2016-03-01

    Prohibitin proteins are multifunctional proteins located mainly at the inner membrane of mitochondria expressed in universal species. They play a vital role in mitochondria's function, cell proteolysis, senescence, apoptosis and as a substrate for ubiquitination. In this study, we used PCR cloning, protein and nucleotide acids alignment, protein structure prediction, western blot, in situ hybridization and immunofluorescence to study the characteristics of the prohibitin gene and the potential role of prohibitin in spermatogenesis and spermiogenesis processes in the Chinese fire-bellied newt Cynops orientalis. First, we cloned a 1452-bp full-length cDNA from the testis of Cynops orientalis. Second, we found that the 272 amino acids of prohibitin have a SPFH family domain. Thirdly, the western blots showed high expression of prohibitin in testis while the protein size was approximately 32 kDa. Fourthly, the results of in situ hybridization and immunofluorescence experiments showed that most of the prohibitins travelled with the mitochondria's migration in Cynops orientalis. The quantities of mRNA decreased as spermiogenesis proceeded, although the signals of prohibitins existed during the whole period of spermatogenesis and spermiogenesis. In the mature germ cells, the signals of prohibitins were weak and aggregated at the end of the cell. Finally, we discovered that the Sertoli cells had a large quantity of prohibitins and we made several assumptions of prohibitins' potential roles in those cells. This is the first time that the relationship between mitochondria and prohibitin in different stages of the sperm cells in Cynops orientalis has been examined, which also revealed that Sertoli cells have abundant prohibitins. PMID:26384251

  10. Expression of Two Classes of Pax6 Transcripts in Reprogramming Retinal Pigment Epithelium Cells of the Adult Newt.

    PubMed

    Inami, Wataru; Islam, Md Rafiqul; Nakamura, Kenta; Yoshikawa, Taro; Yasumuro, Hirofumi; Casco-Robles, Martin Miguel; Toyama, Fubito; Maruo, Fumiaki; Chiba, Chikafumi

    2016-02-01

    The adult newt has the remarkable ability to regenerate a functional retina from retinal pigment epithelium (RPE) cells, even when the neural retina (NR) is completely lost from the eye. In this system, RPE cells are reprogrammed into a unique state of multipotent cells, named RPESCs, in an early phase of retinal regeneration. However, the signals that trigger reprogramming remain unknown. Here, to approach this issue we focused on Pax6, a transcription factor known to be expressed in RPESCs. We first identified four classes (v1, v2, v3 and v4) of Pax6 variants in the eye of adult newt, Cynops pyrrhogaster. These variants were expressed in most tissues of the intact eye in different combinations but not in the RPE, choroid or sclera. On the basis of this information, we investigated the expression of Pax6 in RPE cells after the NR was removed from the eye by surgery (retinectomy), and found that two classes (v1 and v2) of Pax6 variants were newly expressed in RPE cells 10 days after retinectomy, both in vivo and in vitro (RLEC system). In the RLEC system, we found that Pax6 expression is mediated through a pathway separate from the MEK-ERK pathway, which is required for cell cycle re-entry of RPE cells. These results predict the existence of a pathway that may be of fundamental importance to a better understanding of the reprogramming of RPE cells in vivo. PMID:26853865

  11. Purification and molecular cloning of aspartic proteinases from the stomach of adult Japanese fire belly newts, Cynops pyrrhogaster.

    PubMed

    Nagasawa, Tatsuki; Sano, Kaori; Kawaguchi, Mari; Kobayashi, Ken-Ichiro; Yasumasu, Shigeki; Inokuchi, Tomofumi

    2016-04-01

    Six aspartic proteinase precursors, a pro-cathepsin E (ProCatE) and five pepsinogens (Pgs), were purified from the stomach of adult newts (Cynops pyrrhogaster). On sodium dodecylsulfate-polyacrylamide gel electrophoresis, the molecular weights of the Pgs and active enzymes were 37-38 kDa and 31-34 kDa, respectively. The purified ProCatE was a dimer whose subunits were connected by a disulphide bond. cDNA cloning by polymerase chain reaction and subsequent phylogenetic analysis revealed that three of the purified Pgs were classified as PgA and the remaining two were classified as PgBC belonging to C-type Pg. Our results suggest that PgBC is one of the major constituents of acid protease in the urodele stomach. We hypothesize that PgBC is an amphibian-specific Pg that diverged during its evolutional lineage. PgBC was purified and characterized for the first time. The purified urodele pepsin A was completely inhibited by equal molar units of pepstatin A. Conversely, the urodele pepsin BC had low sensitivity to pepstatin A. In acidic condition, the activation rates of newt pepsin A and BC were similar to those of mammalian pepsin A and C1, respectively. Our results suggest that the enzymological characters that distinguish A- and C-type pepsins appear to be conserved in mammals and amphibians. PMID:26711235

  12. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae).

    PubMed

    Van Bocxlaer, Ines; Maex, Margo; Treer, Dag; Janssenswillen, Sunita; Janssens, Rik; Vandebergh, Wim; Proost, Paul; Bossuyt, Franky

    2016-01-01

    Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF's were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide. PMID:26935790

  13. The morphogenic features of otoconia during larval development of Cynops pyrrhogaster, the Japanese red-bellied newt

    NASA Technical Reports Server (NTRS)

    Steyger, P. S.; Wiederhold, M. L.; Batten, J.

    1995-01-01

    Otoconia are calcified protein matrices within the gravity-sensing organs of the vertebrate vestibular system. Mammalian otoconia are barrel-shaped with triplanar facets at each end. Reptilian otoconia are commonly prismatic or fusiform in shape. Amphibians have all three otoconial morphologies, barrel-shaped otoconia within the utricle, with prismatic and fusiform otoconia in the saccule. Scanning electron microscopy revealed a sequential appearance of all three otoconial morphologies during larval development of the newt, Cynops pyrrhogaster. The first otoconia appear within a single, developing otolith, and some resemble adult barrel-shaped otoconia. As the larvae hatch, around stages 39-42, the single otolith divides into two anatomically separate regions, the utricle and saccule, and both contain otoconia similar to those seen in the single otolith. Throughout development, these otoconia may have variable morphologies, with serrated surfaces, or circumferential striations with either separated facets or adjacent facets in the triplanar end-regions. Small fusiform otoconia occur later, at stage 51, and only in the saccule. Prismatic otoconia appear later still, at stage 55, and again only in the saccule. Thus, although prismatic otoconia are the most numerous in adult newts, it is the last vestibular otoconial morphology to be expressed.

  14. Ultrastructure of the endolymphatic sac in the larva of the japanese red-bellied newt Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Gao, W.; Wiederhold, M.; Hejl, R.

    1998-01-01

    The ultrastructure of the endolymphatic sac (ES) of the late stage larva of the Japanese red-bellied newt, Cynops pyrrhogaster (stage 57), was examined by light and transmission electron microscopy. The two endolymphatic sacs are located at the dorsal-medial side of the otic vesicle on the dorsal-lateral side of the midbrain in the cranial cavity. The wall of the sac is composed of a layer of cubical epithelial cells with loose, interposed intercellular spaces. The sac contains a large luminal cavity, in which endolymph and numerous otoconia are present. The epithelial cells of different portions of the sac have a similar structure. These cells contain an abundance of cytoplasmic organelles, including ribosomes, Golgi complexes, and numerous vesicles. Two types of vesicles are found in the epithelial cells: the "floccular" vesicle and the "granular" vesicle. The floccular vesicles are located in the supra- and lateral-nuclear cytoplasm and contain floccular material. The granular vesicles have a fine granular substance and are usually situated apposed to the apical cell membrane. The granular vesicles are suggested to be secreted into the lumen, while the floccular vesicles are thought to be absorbed from the lumen and conveyed to the intercellular spaces by the epithelial cells. The apical surfaces of the epithelial cells bear numerous microvilli. Apparently floating cells, which bear long microvilli on the free surfaces, are observed in the lumen of the ES. Based on the fine structure, the function of the endolymphatic sac of the newt Cynops pyrrhogaster is discussed.

  15. Data concatenation, Bayesian concordance and coalescent-based analyses of the species tree for the rapid radiation of Triturus newts.

    PubMed

    Wielstra, Ben; Arntzen, Jan W; van der Gaag, Kristiaan J; Pabijan, Maciej; Babik, Wieslaw

    2014-01-01

    The phylogenetic relationships for rapid species radiations are difficult to disentangle. Here we study one such case, namely the genus Triturus, which is composed of the marbled and crested newts. We analyze data for 38 genetic markers, positioned in 3-prime untranslated regions of protein-coding genes, obtained with 454 sequencing. Our dataset includes twenty Triturus newts and represents all nine species. Bayesian analysis of population structure allocates all individuals to their respective species. The branching patterns obtained by data concatenation, Bayesian concordance analysis and coalescent-based estimations of the species tree differ from one another. The data concatenation based species tree shows high branch support but branching order is considerably affected by allele choice in the case of heterozygotes in the concatenation process. Bayesian concordance analysis expresses the conflict between individual gene trees for part of the Triturus species tree as low concordance factors. The coalescent-based species tree is relatively similar to a previously published species tree based upon morphology and full mtDNA and any conflicting internal branches are not highly supported. Our findings reflect high gene tree discordance due to incomplete lineage sorting (possibly aggravated by hybridization) in combination with low information content of the markers employed (as can be expected for relatively recent species radiations). This case study highlights the complexity of resolving rapid radiations and we acknowledge that to convincingly resolve the Triturus species tree even more genes will have to be consulted.

  16. Why are the prevalence and diversity of helminths in the endemic Pyrenean brook newt Calotriton asper (Amphibia, Salamandridae) so low?

    PubMed

    Comas, M; Ribas, A

    2015-03-01

    A cornerstone in parasitology is why some species or populations are more parasitized than others. Here we examine the influence of host characteristics and habitat on parasite prevalence. We studied the helminths parasitizing the Pyrenean brook newt Calotriton asper (n= 167), paying special attention to the relationship between parasites and ecological factors such as habitat, sex, ontogeny, body size and age of the host. We detected two species of parasites, Megalobatrachonema terdentatum (Nematoda: Kathlaniidae) and Brachycoelium salamandrae (Trematoda: Brachycoeliidae), with a prevalence of 5.99% and 1.2%, respectively. Marginally significant differences were found in the prevalence between sexes, with females being more parasitized than males. The present results show significant differences in the body length of paedomorphic and metamorphic individuals, the former being smaller. Nevertheless, no significant correlations between parasite prevalence and either newt body length, ontogenetic stage or age were found. In comparison with other Salamandridae living in ponds, prevalence and diversity values were low. This may be due to a long hibernation period, the species' lotic habitat and its reophilous lifestyle, which probably do not allow for a high parasite load.

  17. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae)

    PubMed Central

    Van Bocxlaer, Ines; Maex, Margo; Treer, Dag; Janssenswillen, Sunita; Janssens, Rik; Vandebergh, Wim; Proost, Paul; Bossuyt, Franky

    2016-01-01

    Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF’s were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide. PMID:26935790

  18. Changes in the extracellular matrix and glycosaminoglycan synthesis during the initiation of regeneration in adult newt forelimbs

    SciTech Connect

    Mescher, A.L.; Munaim, S.I.

    1986-04-01

    The extracellular matrix (ECM) of the distal tissues in a newt limb stump is completely reorganized in the 2-3-week period following amputation. In view of numerous in vitro studies showing that extracellular material influences cellular migration and proliferation, it is likely that the changes in the limb's ECM are important activities in the process leading to regeneration of such limbs. Using biochemical, autoradiographic, and histochemical techniques we studied temporal and spatial differences in the synthesis of glycosaminoglycans (GAGs) during the early, nerve-dependent phase of limb regeneration. Hyaluronic acid synthesis began with the onset of tissue dedifferentiation, became maximal within 1 weeks, and continued throughout the period of active cell proliferation. Chondroitin sulfate synthesis began somewhat later, increased steadily, and reached very high levels during chondrogenesis. During the first 10 days after amputation, distributions of sulfated and nonsulfated GAGs were both uniform throughout dedifferentiating tissues, except for a heavier localization near the bone. Since nerves are necessary to promote the regenerative process, we examined the neural influence on synthesis and accumulation of extracellular GAGs. Denervation decreased GAG production in all parts of the limb stump by approximately 50%. Newt dorsal root ganglia and brain-derived fibroblast growth factor each produced twofold stimulation of GAG synthesis in cultured 7-day regenerates. The latter effect was primarily on synthesis of hyaluronic acid. The results indicate that the trophic action of nerves on amphibian limb regeneration includes a positive influence on synthesis and extracellular accumulation of GAGs.

  19. Environmental changes in oxygen tension reveal ROS-dependent neurogenesis and regeneration in the adult newt brain

    PubMed Central

    Hameed, L Shahul; Berg, Daniel A; Belnoue, Laure; Jensen, Lasse D; Cao, Yihai; Simon, András

    2015-01-01

    Organisms need to adapt to the ecological constraints in their habitat. How specific processes reflect such adaptations are difficult to model experimentally. We tested whether environmental shifts in oxygen tension lead to events in the adult newt brain that share features with processes occurring during neuronal regeneration under normoxia. By experimental simulation of varying oxygen concentrations, we show that hypoxia followed by re-oxygenation lead to neuronal death and hallmarks of an injury response, including activation of neural stem cells ultimately leading to neurogenesis. Neural stem cells accumulate reactive oxygen species (ROS) during re-oxygenation and inhibition of ROS biosynthesis counteracts their proliferation as well as neurogenesis. Importantly, regeneration of dopamine neurons under normoxia also depends on ROS-production. These data demonstrate a role for ROS-production in neurogenesis in newts and suggest that this role may have been recruited to the capacity to replace lost neurons in the brain of an adult vertebrate. DOI: http://dx.doi.org/10.7554/eLife.08422.001 PMID:26485032

  20. Beyond sodefrin: evidence for a multi-component pheromone system in the model newt Cynops pyrrhogaster (Salamandridae).

    PubMed

    Van Bocxlaer, Ines; Maex, Margo; Treer, Dag; Janssenswillen, Sunita; Janssens, Rik; Vandebergh, Wim; Proost, Paul; Bossuyt, Franky

    2016-03-03

    Sodefrin, a decapeptide isolated from the male dorsal gland of the Japanese fire belly newt Cynops pyrrhogaster, was the first peptide pheromone identified from a vertebrate. The fire belly salamander and sodefrin have become a model for sex pheromone investigation in aquatically courting salamanders ever since. Subsequent studies in other salamanders identified SPF protein courtship pheromones of around 20 kDa belonging to the same gene-family. Although transcripts of these proteins could be PCR-amplified in Cynops, it is currently unknown whether they effectively use full-length SPF pheromones next to sodefrin. Here we combined transcriptomics, proteomics and phylogenetics to investigate SPF pheromone use in Cynops pyrrhogaster. Our data show that not sodefrin transcripts, but multiple SPF transcripts make up the majority of the expression profile in the dorsal gland of this newt. Proteome analyses of water in which a male has been courting confirm that this protein blend is effectively secreted and tail-fanned to the female. By combining phylogenetics and expression data, we show that independent evolutionary lineages of these SPF's were already expressed in ancestral Cynops species before the origin of sodefrin. Extant Cynops species continue to use this multi-component pheromone system, consisting of various proteins in addition to a lineage-specific peptide.

  1. Purification and molecular cloning of aspartic proteinases from the stomach of adult Japanese fire belly newts, Cynops pyrrhogaster.

    PubMed

    Nagasawa, Tatsuki; Sano, Kaori; Kawaguchi, Mari; Kobayashi, Ken-Ichiro; Yasumasu, Shigeki; Inokuchi, Tomofumi

    2016-04-01

    Six aspartic proteinase precursors, a pro-cathepsin E (ProCatE) and five pepsinogens (Pgs), were purified from the stomach of adult newts (Cynops pyrrhogaster). On sodium dodecylsulfate-polyacrylamide gel electrophoresis, the molecular weights of the Pgs and active enzymes were 37-38 kDa and 31-34 kDa, respectively. The purified ProCatE was a dimer whose subunits were connected by a disulphide bond. cDNA cloning by polymerase chain reaction and subsequent phylogenetic analysis revealed that three of the purified Pgs were classified as PgA and the remaining two were classified as PgBC belonging to C-type Pg. Our results suggest that PgBC is one of the major constituents of acid protease in the urodele stomach. We hypothesize that PgBC is an amphibian-specific Pg that diverged during its evolutional lineage. PgBC was purified and characterized for the first time. The purified urodele pepsin A was completely inhibited by equal molar units of pepstatin A. Conversely, the urodele pepsin BC had low sensitivity to pepstatin A. In acidic condition, the activation rates of newt pepsin A and BC were similar to those of mammalian pepsin A and C1, respectively. Our results suggest that the enzymological characters that distinguish A- and C-type pepsins appear to be conserved in mammals and amphibians.

  2. Prolactin increases the synthesis of 7alpha-hydroxypregnenolone, a key factor for induction of locomotor activity, in breeding male Newts.

    PubMed

    Haraguchi, Shogo; Koyama, Teppei; Hasunuma, Itaru; Vaudry, Hubert; Tsutsui, Kazuyoshi

    2010-05-01

    We recently found that the Japanese red-bellied newt, Cynops pyrrhogaster, actively produces 7alpha-hydroxypregnenolone, a previously undescribed amphibian neurosteroid. 7alpha-Hydroxypregnenolone stimulates locomotor activity of male newts. Locomotor activity of male newts increases during the breeding period as in other wild animals, but the molecular mechanism for such a change in locomotor activity is poorly understood. Here we show that the adenohypophyseal hormone prolactin (PRL) stimulates 7alpha-hydroxypregnenolone synthesis in the brain, thus increasing locomotor activity of breeding male newts. In this study, cytochrome P450(7alpha) (CYP7B), a steroidogenic enzyme catalyzing the formation of 7alpha-hydroxypregnenolone, was first identified to analyze seasonal changes in 7alpha-hydroxypregnenolone synthesis. Only males exhibited marked seasonal changes in 7alpha-hydroxypregnenolone synthesis and CYP7B expression in the brain, with a maximum level in the spring breeding period when locomotor activity of males increases. Subsequently we identified PRL as a key component of the mechanism regulating 7alpha-hydroxypregnenolone synthesis. Hypophysectomy decreased 7alpha-hydroxypregnenolone synthesis in the male brain, whereas administration of PRL but not gonadotropins to hypophysectomized males caused a dose-dependent increase in 7alpha-hydroxypregnenolone synthesis. To analyze the mode of PRL action, CYP7B and the receptor for PRL were localized in the male brain. PRL receptor was expressed in the neurons expressing CYP7B in the magnocellular preoptic nucleus. Thus, PRL appears to act directly on neurosteroidogenic magnocellular preoptic nucleus neurons to regulate 7alpha-hydroxypregnenolone synthesis, thus inducing seasonal locomotor changes in male newts. This is the first report describing the regulation of neurosteroidogenesis in the brain by an adenohypophyseal hormone in any vertebrate.

  3. 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.

  4. Computational Modeling of the Ames 11-Ft Transonic Wind Tunnel in Conjunction with IofNEWT

    NASA Technical Reports Server (NTRS)

    Djomehri, M. Jahed; Buning, Pieter G.; Erickson, Larry L.; George, Michael W. (Technical Monitor)

    1995-01-01

    Technical advances in Computational Fluid Dynamics have now made it possible to simulate complex three-dimensional internal flows about models of various size placed in a Transonic Wind Tunnel. TWT wall interference effects have been a source of error in predicting flight data from actual wind tunnel measured data. An advantage of such internal CFD calculations is to directly compare numerical results with the actual tunnel data for code assessment and tunnel flow analysis. A CFD capability has recently been devised for flow analysis of the NASA/Ames 11-Ft TWT facility. The primary objectives of this work are to provide a CFD tool to study the NASA/Ames 11-Ft TWT flow characteristics, to understand the slotted wall interference effects, and to validate CFD codes. A secondary objective is to integrate the internal flowfield calculations with the Pressure Sensitive Paint data, a surface pressure distribution capability in Ames' production wind tunnels. The effort has been part of the Ames IofNEWT, Integration of Numerical and Experimental Wind Tunnels project, which is aimed at providing further analytical tools for industrial application. We used the NASA/Ames OVERFLOW code to solve the thin-layer Navier-Stokes equations. Viscosity effects near the model are captured by Baldwin-Lomax or Baldwin-Barth turbulence models. The solver was modified to model the flow behavior in the vicinity of the tunnel longitudinal slotted walls. A suitable porous type wall boundary condition was coded to account for the cross-flow through the test section. Viscous flow equations were solved in generalized coordinates with a three-factor implicit central difference scheme in conjunction with the Chimera grid procedure. The internal flow field about the model and the tunnel walls were descretized by the Chimera overset grid system. This approach allows the application of efficient grid generation codes about individual components of the configuration; separate minor grids were developed

  5. Development of the endolymphatic sac and duct in the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Gao, W.; Wiederhold, M. L.; Harrison, J. L.

    1998-01-01

    The development and maturation of the endolymphatic sac (ES) and duct (ED) were studied in the newt Cynops pyrrhogaster. The ES first appears as an oval capsule at the dorsal-medial tip of the otic vesicle at stage 39, about 11 days after oviposition. The ES consists of polymorphous epithelial cells with a minimum of cytoplasm. The intercellular space (IS) between the epithelial cells is narrow and has a smooth surface. At stage 44, the size of the ES increases as many vacuoles in the IS become filled. At stage 46, 18 days after oviposition, the ES elongates markedly and a slit-like lumen is found in the ES. The epithelium contains a few cell organelles which are scattered in the cytoplasm. The vacuoles in the IS are fused, which expands the IS. Two days later (stage 48), floccular material (endolymph) is present in the expanded lumen. The IS dilates and has a wide and irregular appearance. At stage 50, approximately 26 days after oviposition, the ES extends and expands significantly and crystals (otoconia) can now be seen in the widened lumen of the ES. The cytoplasm of the cuboidal epithelial cells contains an abundance of vesicles surrounded by ribosomes and Golgi complexes. Intercellular digitations are formed in the expanded IS. At stage 54, the ES forms a large bellow-like pouch. Numerous otoconia accumulate in the lumen. Free floating cells and cell debris can be seen in the lumen at this stage. The epithelial cells contain numerous cytoplasmic organelles which are evenly distributed in the cytoplasm. Granules are found in the apical and lateral cytoplasm. The IS is loose and displays a labyrinthine appearance. The primitive ED first appears as a connection between the ES and the saccule but no lumen is present inside at stage 39. At stage 46, a narrow lumen is formed in the ED, which corresponds to the formation of the ES lumen. At stage 50, as the ED extends, floccular material is seen in the lumen. At stage 54, the ED bears numerous microvilli on its

  6. Crest evolution in newts: implications for reconstruction methods, sexual selection, phenotypic plasticity and the origin of novelties.

    PubMed

    Wiens, J J; Sparreboom, M; Arntzen, J W

    2011-10-01

    The dorsal crest of newts (Salamandridae) is a novel, phenotypically plastic, sexually selected trait that may evolve in association with complex courtship behaviours. We estimated a near-comprehensive, time-calibrated phylogeny for salamandrids and analysed the evolution of their crests and display behaviour. Different models give conflicting reconstructions for crest evolution, showing that likelihood can estimate incorrect ancestral states with strong statistical support. The best-fitting model suggests that crests evolved once and were lost repeatedly, supporting the hypothesis that sexually selected traits may be frequently lost. We demonstrate the correlated evolution of crests and courtship behaviour and show that species with larger numbers of crest-related traits have larger repertoires of behaviours. We also show that phenotypically plastic morphological traits can be maintained over long macroevolutionary timescales (∼25-48 Myr). Finally, we use salamandrids to address how novel structures may arise, and support a model involving the expansion and subdivision of pre-existing structures.

  7. Kinetochores are transported poleward along a single astral microtubule during chromosome attachment to the spindle in newt lung cells

    PubMed Central

    1990-01-01

    During mitosis in cultured newt pneumocytes, one or more chromosomes may become positioned well removed (greater than 50 microns) from the polar regions during early prometaphase. As a result, these chromosomes are delayed for up to 5 h in forming an attachment to the spindle. The spatial separation of these chromosomes from the polar microtubule- nucleating centers provides a unique opportunity to study the initial stages of kinetochore fiber formation in living cells. Time-lapse Nomarski-differential interference contrast videomicroscopic observations reveal that late-attaching chromosomes always move, upon attachment, into a single polar region (usually the one closest to the chromosome). During this attachment, the kinetochore region of the chromosome undergoes a variable number of transient poleward tugs that are followed, shortly thereafter, by rapid movement of the chromosome towards the pole. Anti-tubulin immunofluorescence and serial section EM reveal that the kinetochores and kinetochore regions of nonattached chromosomes lack associated microtubules. By contrast, these methods reveal that the attachment and subsequent poleward movement of a chromosome correlates with the association of a single long microtubule with one of the kinetochores of the chromosome. This microtubule traverses the entire distance between the spindle pole and the kinetochore and often extends well past the kinetochore. From these results, we conclude that the initial attachment of a chromosome to the newt pneumocyte spindle results from an interaction between a single polar-nucleated microtubule and one of the kinetochores on the chromosome. Once this association is established, the kinetochore is rapidly transported poleward along the surface of the microtubule by a mechanism that is not dependent on microtubule depolymerization. Our results further demonstrate that the motors for prometaphase chromosome movement must be either on the surface of the kinetochore (i.e., within the

  8. Effects of water contamination on site selection by amphibians: experiences from an arena approach with European frogs and newts.

    PubMed

    Wagner, Norman; Lötters, Stefan

    2013-07-01

    Pesticide residues in breeding ponds can cause avoidance by at least some amphibian species. So far, outdoor experiments have been performed only with artificial pools in areas where the focus species usually occur and new colonization has been observed. Results of this kind of study are potentially influenced by natural disturbances and therefore are of limited comparability. We used an easily manufactured and standardizable arena approach, in which animals in reproductive condition for some hours had a choice among pools with different concentrations of a contaminant. Because there has been much debate on the potential environmental impacts of glyphosate-based herbicides, we investigated the impact of glyphosate isopropylamine salt (GLY-IS), Roundup LB PLUS (RU-LB-PLUS), and glyphosate's main metabolite aminomethylphosphonic acid (AMPA) on individual residence time in water. The following European amphibian species were tested: Common frog (Rana temporaria), Palmate newt (Lissotriton helveticus), and Alpine newt (Ichthyosaura alpestris). The residence time in water was not significantly affected by concentrations below or slightly above the European Environmental Quality Standards for AMPA or the German "worst-case" expected environmental concentrations for GLY-IS and RU-LB-PLUS. Occasionally, microclimatic cofactors (nightly minimum ground temperature, water temperature) apparently influenced the residence time. The major drawback of such quick behavior studies is that results can only be transferred to perception and avoidance of contaminated water but not easily to site selection by amphibians. For example, testing oviposition site selection requires more natural water bodies and more time. Hence, to develop a standard procedure in risk assessment, an intermediate design between an arena approach, as presented here, and previously performed field studies should be tested.

  9. Study of the genotoxic activity of six halogenated acetonitriles, using the SOS chromotest, the Ames-fluctuation test and the newt micronucleus test.

    PubMed

    Le Curieux, F; Giller, S; Gauthier, L; Erb, F; Marzin, D

    1995-02-01

    Three short-term assays (the SOS chromotest, the Ames-fluctuation test and the newt micronucleus test) were carried out to evaluate the genotoxicity of six halogenated acetonitriles identified in chlorinated waters (monochloro-, dichloro-, trichloro-, monobromo-, dibromo- and bromochloroacetonitrile). With the SOS chromotest, three of the chemicals studied (dichloro-, dibromo- and bromochloroacetonitrile) were found to induce primary DNA damage in Escherichia coli PQ37. In the Ames-fluctuation test, all the compounds except dibromoacetonitrile showed mutagenic activity on Salmonella typhimurium strain TA100. The newt micronucleus assay detected a clastogenic effect on the peripheral blood erythrocytes of Pleurodeles waltl larvae for all the six haloacetonitriles studied. Moreover, two structure-activity relationships were noted: (1) the genotoxic activity of haloacetonitriles containing bromine substituents appeared higher than the corresponding chlorinated acetonitriles and (2) the clastogenic activity of the chlorinated acetonitriles increased with the number of chlorine substituents.

  10. Why does the yellow-eyed Ensatina have yellow eyes? Batesian mimicry of Pacific newts (genus Taricha) by the salamander Ensatina eschscholtzii xanthoptica.

    PubMed

    Kuchta, Shawn R; Krakauer, Alan H; Sinervo, Barry

    2008-04-01

    Color patterns commonly vary geographically within species, but it is rare that such variation corresponds with divergent antipredator strategies. The polymorphic salamander Ensatina eschscholtzii, however, may represent such a case. In this species, most subspecies are cryptically colored, whereas E. e. xanthoptica, the Yellow eyed ensatina, is hypothesized to be an aposematic mimic of highly toxic Pacific newts (genus Taricha). To test the mimicry hypothesis, we conducted feeding trials using Western Scrub-Jays, Aphelocoma californica. In every feeding trial, we found that jays, following presentation with the presumed model (T. torosa), were more hesitant to contact the presumed mimic (E. e. xanthoptica) than a control subspecies lacking the postulated aposematic colors (E. e. oregonensis). The median time to contact was 315 sec for the mimic and 52 sec for the control. These results support the mimicry hypothesis, and we suggest that E. e. xanthoptica is likely a Batesian mimic, rather a Müllerian or quasi-Batesian mimic, of Pacific newts.

  11. Parallel tagged amplicon sequencing of transcriptome-based genetic markers for Triturus newts with the Ion Torrent next-generation sequencing platform

    PubMed Central

    Wielstra, B; Duijm, E; Lagler, P; Lammers, Y; Meilink, W R M; Ziermann, J M; Arntzen, J W

    2014-01-01

    Next-generation sequencing is a fast and cost-effective way to obtain sequence data for nonmodel organisms for many markers and for many individuals. We describe a protocol through which we obtain orthologous markers for the crested newts (Amphibia: Salamandridae: Triturus), suitable for analysis of interspecific hybridization. We use transcriptome data of a single Triturus species and design 96 primer pairs that amplify c. 180 bp fragments positioned in 3-prime untranslated regions. Next, these markers are tested with uniplex PCR for a set of species spanning the taxonomical width of the genus Triturus. The 52 markers that consistently show a single band of expected length at gel electrophoreses for all tested crested newt species are then amplified in five multiplex PCRs (with a plexity of ten or eleven) for 132 individual newts: a set of 84 representing the seven (candidate) species and a set of 48 from a presumed hybrid population. After pooling multiplexes per individual, unique tags are ligated to link amplicons to individuals. Subsequently, individuals are pooled equimolar and sequenced on the Ion Torrent next-generation sequencing platform. A bioinformatics pipeline identifies the alleles and recodes these to a genotypic format. Next, we test the utility of our markers. baps allocates the 84 crested newt individuals representing (candidate) species to their expected (candidate) species, confirming the markers are suitable for species delineation. newhybrids, a hybrid index and hiest confirm the 48 individuals from the presumed hybrid population to be genetically admixed, illustrating the potential of the markers to identify interspecific hybridization. We expect the set of markers we designed to provide a high resolving power for analysis of hybridization in Triturus. PMID:24571307

  12. The effects of sex steroids and vasotocin on behavioral responses to visual and olfactory sexual stimuli in ovariectomized female roughskin newts.

    PubMed

    Thompson, R R; Moore, F L

    2003-11-01

    Previous studies have found that vasotocin (AVT) administration to male roughskin newts (Taricha granulosa) enhances courtship clasping as well as appetitive responses to specific sexual stimuli and that treating female newts with androgens plus AVT induces the expression of male-typical courtship clasping (the selective clasping of females). However, the unique and/or interactive effects of sex steroids and AVT on appetitive responses to specific sexual stimuli have not yet been determined. To first identify male-typical, sexually dimorphic appetitive responses to female sexual stimuli, we tested intact newts during the breeding season and found that males, but not females, are attracted to female visual and pheromonal sexual stimuli. We then used ovariectomized (ovx) females implanted with empty silastic capsules (Blk) or with capsules containing testosterone (T), dihydrotestosterone (DHT), or estradiol (E2) and then injected with either saline or AVT to determine the effects of steroids and AVT, alone or in combination with each other, on male-typical behavioral responses to those stimuli. E2 treatment depressed responses toward female visual stimuli independently of AVT. On the other hand, only T-implanted, AVT-injected females displayed male-typical behavioral responses toward female olfactory stimuli, preferring to spend more time in proximity to female-scented than unscented newt models and selectively clasping the female-scented models. Together, these results support the conclusion that sex steroids and AVT influence behavioral responses to sexual stimuli via sensory-specific mechanisms. Furthermore, they suggest that T and AVT interact within the brain to influence sensorimotor processing in the pathways that integrate olfactory sexual stimuli into male-typical courtship behaviors.

  13. Parallel tagged amplicon sequencing of transcriptome-based genetic markers for Triturus newts with the Ion Torrent next-generation sequencing platform.

    PubMed

    Wielstra, B; Duijm, E; Lagler, P; Lammers, Y; Meilink, W R M; Ziermann, J M; Arntzen, J W

    2014-09-01

    Next-generation sequencing is a fast and cost-effective way to obtain sequence data for nonmodel organisms for many markers and for many individuals. We describe a protocol through which we obtain orthologous markers for the crested newts (Amphibia: Salamandridae: Triturus), suitable for analysis of interspecific hybridization. We use transcriptome data of a single Triturus species and design 96 primer pairs that amplify c. 180 bp fragments positioned in 3-prime untranslated regions. Next, these markers are tested with uniplex PCR for a set of species spanning the taxonomical width of the genus Triturus. The 52 markers that consistently show a single band of expected length at gel electrophoreses for all tested crested newt species are then amplified in five multiplex PCRs (with a plexity of ten or eleven) for 132 individual newts: a set of 84 representing the seven (candidate) species and a set of 48 from a presumed hybrid population. After pooling multiplexes per individual, unique tags are ligated to link amplicons to individuals. Subsequently, individuals are pooled equimolar and sequenced on the Ion Torrent next-generation sequencing platform. A bioinformatics pipeline identifies the alleles and recodes these to a genotypic format. Next, we test the utility of our markers. baps allocates the 84 crested newt individuals representing (candidate) species to their expected (candidate) species, confirming the markers are suitable for species delineation. newhybrids, a hybrid index and hiest confirm the 48 individuals from the presumed hybrid population to be genetically admixed, illustrating the potential of the markers to identify interspecific hybridization. We expect the set of markers we designed to provide a high resolving power for analysis of hybridization in Triturus.

  14. Mitochondrial genomes and divergence times of crocodile newts: inter-islands distribution of Echinotriton andersoni and the origin of a unique repetitive sequence found in Tylototriton mt genomes.

    PubMed

    Kurabayashi, Atsushi; Nishitani, Takuma; Katsuren, Seiki; Oumi, Shohei; Sumida, Masayuki

    2012-01-01

    Crocodile newts, which constitute the genera Echinotriton and Tylototriton, are known as living fossils, and these genera comprise many endangered species. To identify mitochondrial (mt) genes suitable for future population genetic analyses for endangered taxa, we determined the complete nucleotide sequences of the mt genomes of the Japanese crocodile newt Echinotriton andersoni and Himalayan crocodile newt Tylototriton verrucosus. Although the control region (CR) is known as the most variable mtDNA region in many animal taxa, the CRs of crocodile newts are highly conservative. Rather, the genes of NADH dehydrogenase subunits and ATPase subunit 6 were found to have high sequence divergences and to be usable for population genetics studies. To estimate the inter-population divergence ages of E. andersoni endemic to the Ryukyu Islands, we performed molecular dating analysis using whole and partial mt genomic data. The estimated divergence ages of the inter-island individuals are older than the paleogeographic segmentation ages of the islands, suggesting that the lineage splits of E. andersoni populations were not caused by vicariant events. Our phylogenetic analysis with partial mt sequence data also suggests the existence of at least two more undescribed species in the genus Tylototriton. We also found unusual repeat sequences containing the 3' region of cytochrome apoenzyme b gene, whole tRNA-Thr gene, and a noncoding region (the T-P noncoding region characteristic in caudate mtDNAs) from T. verrucosus mtDNA. Similar repeat sequences were found in two other Tylototriton species. The Tylototriton taxa with the repeats become a monophyletic group, indicating a single origin of the repeat sequences. The intra-and inter-specific comparisons of the repeat sequences suggest the occurrences of homologous recombination-based concerted evolution among the repeat sequences.

  15. Most of the Dominant Members of Amphibian Skin Bacterial Communities Can Be Readily Cultured.

    PubMed

    Walke, Jenifer B; Becker, Matthew H; Hughey, Myra C; Swartwout, Meredith C; Jensen, Roderick V; Belden, Lisa K

    2015-10-01

    Currently, it is estimated that only 0.001% to 15% of bacteria in any given system can be cultured by use of commonly used techniques and media, yet culturing is critically important for investigations of bacterial function. Despite this situation, few studies have attempted to link culture-dependent and culture-independent data for a single system to better understand which members of the microbial community are readily cultured. In amphibians, some cutaneous bacterial symbionts can inhibit establishment and growth of the fungal pathogen Batrachochytrium dendrobatidis, and thus there is great interest in using these symbionts as probiotics for the conservation of amphibians threatened by B. dendrobatidis. The present study examined the portion of the culture-independent bacterial community (based on Illumina amplicon sequencing of the 16S rRNA gene) that was cultured with R2A low-nutrient agar and whether the cultured bacteria represented rare or dominant members of the community in the following four amphibian species: bullfrogs (Lithobates catesbeianus), eastern newts (Notophthalmus viridescens), spring peepers (Pseudacris crucifer), and American toads (Anaxyrus americanus). To determine which percentage of the community was cultured, we clustered Illumina sequences at 97% similarity, using the culture sequences as a reference database. For each amphibian species, we cultured, on average, 0.59% to 1.12% of each individual's bacterial community. However, the average percentage of bacteria that were culturable for each amphibian species was higher, with averages ranging from 2.81% to 7.47%. Furthermore, most of the dominant operational taxonomic units (OTUs), families, and phyla were represented in our cultures. These results open up new research avenues for understanding the functional roles of these dominant bacteria in host health. PMID:26162880

  16. Light-dependent magnetic compass in Iberian green frog tadpoles

    NASA Astrophysics Data System (ADS)

    Diego-Rasilla, Francisco Javier; Luengo, Rosa Milagros; Phillips, John B.

    2010-12-01

    Here, we provide evidence for a wavelength-dependent effect of light on magnetic compass orientation in Pelophylax perezi (order Anura), similar to that observed in Rana catesbeiana (order Anura) and Notophthalmus viridescens (order Urodela), and confirm for the first time in an anuran amphibian that a 90° shift in the direction of magnetic compass orientation under long-wavelength light (≥500 nm) is due to a direct effect of light on the underlying magnetoreception mechanism. Although magnetic compass orientation in other animals (e.g., birds and some insects) has been shown to be influenced by the wavelength and/or intensity of light, these two amphibian orders are the only taxa for which there is direct evidence that the magnetic compass is light-dependent. The remarkable similarities in the light-dependent magnetic compasses of anurans and urodeles, which have evolved as separate clades for at least 250 million years, suggest that the light-dependent magnetoreception mechanism is likely to have evolved in the common ancestor of the Lissamphibia (Early Permian, ~294 million years) and, possibly, much earlier. Also, we discuss a number of similarities between the functional properties of the light-dependent magnetic compass in amphibians and blue light-dependent responses to magnetic stimuli in Drosophila melanogaster, which suggest that the wavelength-dependent 90° shift in amphibians may be due to light activation of different redox forms of a cryptochrome photopigment. Finally, we relate these findings to earlier studies showing that the pineal organ of newts is the site of the light-dependent magnetic compass and recent neurophysiological evidence showing magnetic field sensitivity in the frog frontal organ (an outgrowth of the pineal).

  17. Most of the Dominant Members of Amphibian Skin Bacterial Communities Can Be Readily Cultured

    PubMed Central

    Becker, Matthew H.; Hughey, Myra C.; Swartwout, Meredith C.; Jensen, Roderick V.; Belden, Lisa K.

    2015-01-01

    Currently, it is estimated that only 0.001% to 15% of bacteria in any given system can be cultured by use of commonly used techniques and media, yet culturing is critically important for investigations of bacterial function. Despite this situation, few studies have attempted to link culture-dependent and culture-independent data for a single system to better understand which members of the microbial community are readily cultured. In amphibians, some cutaneous bacterial symbionts can inhibit establishment and growth of the fungal pathogen Batrachochytrium dendrobatidis, and thus there is great interest in using these symbionts as probiotics for the conservation of amphibians threatened by B. dendrobatidis. The present study examined the portion of the culture-independent bacterial community (based on Illumina amplicon sequencing of the 16S rRNA gene) that was cultured with R2A low-nutrient agar and whether the cultured bacteria represented rare or dominant members of the community in the following four amphibian species: bullfrogs (Lithobates catesbeianus), eastern newts (Notophthalmus viridescens), spring peepers (Pseudacris crucifer), and American toads (Anaxyrus americanus). To determine which percentage of the community was cultured, we clustered Illumina sequences at 97% similarity, using the culture sequences as a reference database. For each amphibian species, we cultured, on average, 0.59% to 1.12% of each individual's bacterial community. However, the average percentage of bacteria that were culturable for each amphibian species was higher, with averages ranging from 2.81% to 7.47%. Furthermore, most of the dominant operational taxonomic units (OTUs), families, and phyla were represented in our cultures. These results open up new research avenues for understanding the functional roles of these dominant bacteria in host health. PMID:26162880

  18. Impact of both desiccation and exposure to an emergent skin pathogen on transepidermal water exchange in the palmate newt Lissotriton helveticus .

    PubMed

    Wardziak, Thomas; Luquet, Emilien; Plenet, Sandrine; Léna, Jean-Paul; Oxarango, Laurent; Joly, Pierre

    2013-06-13

    Amphibians are the vertebrate group most affected by global change. Their highly permeable skin is involved in maintaining homeostasis (e.g. water and electrolyte equilibrium), which makes them particularly vulnerable to climate warming and skin pathogens. This study focused on the impacts of both desiccation (as a potential consequence of climate warming) and exposure to Batrachochytrium dendrobatidis (Bd), an emergent skin pathogen of amphibians. Bd causes chytridiomycosis, a lethal skin disease of amphibians, and is responsible for mass mortality events in several regions of the world. Because Bd colonizes the superficial layers of the epidermis, it is assumed to affect water transfer across the skin. We investigated the behavioural postures of the palmate newt Lissotriton helveticus expressed in response to desiccation and their influence on transepidermal water loss (TEWL) rate. We also investigated the effects of repeated 24 h exposure to Bd (i.e. every 4 d for 16 d) on the TEWL and ventral water absorption (VWA) rates of these newts. Our results suggest an efficient behavioural water-conserving mechanism, i.e. an 'S'-shaped posture associated with a restricted activity rate, not affected by repeated exposure to Bd. Similarly, TEWL was not significantly affected in exposed newts. VWA was significantly reduced after just 24 h exposure to Bd without modification until the end of the experiments. Our results suggest that Bd could rapidly inhibit rehydration of L. helveticus through fungal toxins and disrupt an essential function for survival.

  19. Effects of ghrelin and motilin on smooth muscle contractility of the isolated gastrointestinal tract from the bullfrog and Japanese fire belly newt.

    PubMed

    Kitazawa, Takio; Shimazaki, Misato; Kikuta, Ayumi; Yaosaka, Noriko; Teraoka, Hiroki; Kaiya, Hiroyuki

    2016-06-01

    Ghrelin has been identified in some amphibians and is known to stimulate growth hormone release and food intake as seen in mammals. Ghrelin regulates gastrointestinal motility in mammals and birds. The aim of this study was to determine whether ghrelin affects gastrointestinal smooth muscle contractility in bullfrogs (anuran) and Japanese fire belly newts (urodelian) in vitro. Neither bullfrog ghrelin nor rat ghrelin affected longitudinal smooth muscle contractility of gastrointestinal strips from the bullfrog. Expression of growth hormone secretagogue receptor 1a (GHS-R1a) mRNA was confirmed in the bullfrog gastrointestinal tract, and the expression level in the gastric mucosa was lower than that in the intestinal mucosa. In contrast, some gastrointestinal peptides, including substance P, neurotensin and motilin, and the muscarinic receptor agonist carbachol showed marked contraction, indicating normality of the smooth muscle preparations. Similar results were obtained in another amphibian, the Japanese fire belly newt. Newt ghrelin and rat ghrelin did not cause any contraction in gastrointestinal longitudinal muscle, whereas substance P and carbachol were effective causing contraction. In conclusion, ghrelin does not affect contractility of the gastrointestinal smooth muscle in anuran and urodelian amphibians, similar to results for rainbow trout and goldfish (fish) but different from results for rats and chickens. The results suggest diversity of ghrelin actions on the gastrointestinal tract across animals. This study also showed for the first time that motilin induces gastrointestinal contraction in amphibians. PMID:26704852

  20. On the amphibious food uptake and prey manipulation behavior in the Balkan-Anatolian crested newt (Triturus ivanbureschi, Arntzen and Wielstra, 2013).

    PubMed

    Lukanov, Simeon; Tzankov, Nikolay; Handschuh, Stephan; Heiss, Egon; Naumov, Borislav; Natchev, Nikolay

    2016-06-01

    Feeding behavior in salamanders undergoing seasonal habitat shifts poses substantial challenges caused by differences in the physical properties of air and water. Adapting to these specific environments, urodelans use suction feeding predominantly under water as opposed to lingual food prehension on land. This study aims to determine the functionality of aquatic and terrestrial feeding behavior in the Balkan-Anatolian crested newt (Triturus ivanbureschi) in its terrestrial stage. During the terrestrial stage, these newts feed frequently in water where they use hydrodynamic mechanisms for prey capture. On land, prey apprehension is accomplished mainly by lingual prehension, while jaw prehension seems to be the exception (16.67%) in all terrestrial prey capture events. In jaw prehension events there was no detectable depression of the hyo-lingual complex. The success of terrestrial prey capture was significantly higher when T. ivanbureschi used lingual prehension. In addition to prey capture, we studied the mechanisms involved in the subduction of prey. In both media, the newts frequently used a shaking behavior to immobilize the captured earthworms. Apparently, prey shaking constitutes a significant element in the feeding behavior of T. ivanbureschi. Prey immobilization was applied more frequently during underwater feeding, which necessitates a discussion of the influence of the feeding media on food manipulation. We also investigated the osteology of the cranio-cervical complex in T. ivanbureschi to compare it to that of the predominantly terrestrial salamandrid Salamandra salamandra. PMID:27013264

  1. The alpha1 isoform of the Na+/K+ ATPase is up-regulated in dedifferentiated progenitor cells that mediate lens and retina regeneration in adult newts.

    PubMed

    Vergara, M Natalia; Smiley, Laura K; Del Rio-Tsonis, Katia; Tsonis, Panagiotis A

    2009-02-01

    Adult newts are able to regenerate their retina and lens after injury or complete removal through transdifferentiation of the pigmented epithelial tissues of the eye. This process needs to be tightly controlled, and several different mechanisms are likely to be recruited for this function. The Na(+)/K(+) ATPase is a transmembrane protein that establishes electrochemical gradients through the transport of Na(+) and K(+) and has been implicated in the modulation of key cellular processes such as cell division, migration and adhesion. Even though it is expressed in all cells, its isoform composition varies with cell type and is tightly controlled during development and regeneration. In the present study we characterize the expression pattern of Na(+)/K(+) ATPase alpha1 in the adult newt eye and during the process of lens and retina regeneration. We show that this isoform is up-regulated in undifferentiated cells during transdifferentiation. Such change in composition could be one of the mechanisms that newt cells utilize to modulate this process.

  2. Studies on hemopoietic tissue of ribbed newt, Pleurodeles waltl after the flight on board Russian satellite "Foton- M2" in 2005

    NASA Astrophysics Data System (ADS)

    Domaratskaya, E.; Payushina, O.; Butorina, N.; Nikonova, T.; Grigoryan, E.; Mitashov, V.; Almeida, E.; Tairbekov, M.; Khrushchov, N.

    The effect of 16-day spaceflight aboard the Foton-M2 satellite on the hematopoietic tissue of P waltl newts was studied in flown intact animals F-int and in animals used in experiments on tail and lens regeneration under spaceflight conditions F-reg In addition to the flown animals studies were performed on synchronous and aquarial controls in the case of non-operated animals and on synchronous and basal controls in the case of operated newts The main hematopoietic organs of urodelian species are the liver spleen and peripheral blood Therefore we determined differential blood counts estimated the weight of the liver and the content of its hematopoietic cells and histologically assessed spleen and liver in the above experimental groups and the corresponding control groups of animals No significant differences between these groups were revealed with respect to the structure of hematopoietic zones of the liver the content of hematopoietic cells in the liver and spleen morphology However liver weight in newts of the F-reg group was significantly greater than in the F-int group In the peripheral blood neutrophils eosinophils basophils lymphocytes and monocytes were found Lymphocytes L and neutrophils N prevailed accounting for about 50 and 38 of white blood cells respectively Among neutrophils cells differing in the degree of maturity were distinguished myelocytes M metamyelocytes Mm band B and segmented forms S For each group of animals we determined the ratio of maturing M Mm B to mature S

  3. The Apoptotic Function Analysis of p53, Apaf1, Caspase3 and Caspase7 during the Spermatogenesis of the Chinese Fire-Bellied Newt Cynops orientalis

    PubMed Central

    Wang, Li-Ya; Hu, Yan-Jun; Tan, Fu-Qing; Zhou, Hong; Shao, Jian-Zhong; Yang, Wan-Xi

    2012-01-01

    Background Spontaneous and stress-induced germ cell apoptosis during spermatogenesis of multicellular organisms have been investigated broadly in mammals. Spermatogenetic process in urodele amphibians was essentially like that in mammals in spite of morphological differences; however, the mechanism of germ cell apoptosis in urodele amphibians remains unknown. The Chinese fire-belly newt, Cynops orientalis, was an excellent organism for studying germ cell apoptosis due to its sensitiveness to temperature, strong endurance of starvation, and sensitive skin to heavy metal exposure. Methodology/Principal Findings TUNEL result showed that spontaneous germ cell apoptosis took place in normal newt, and severe stress-induced apoptosis occurred to spermatids and sperm in response to heat shock (40°C 2 h), cold exposure(4°C 12 h), cadmium exposure(Cd 36 h), and starvation stress. Quantitative reverse transcription polymerase chain reactions (qRT-PCR) showed that gene expression of Caspase3 or Caspase7 was obviously elevated after stress treatment. Apaf1 was not altered at its gene expression level, and p53 was significantly decreased after various stress treatment. Caspase assay demonstrated that Caspase-3, -8,-9 enzyme activities in newt testis were significantly elevated after heat shock (40°C 2 h), cold exposure(4°C 12 h), and cadmium exposure(Cd 36 h), while Caspase3 and Caspase8 activities were increased with Caspase9 significantly decreased after starvation treatment. Conclusions/Significance Severe germ cell apoptosis triggered by heat shock, cold exposure, and cadmium exposure was Caspase3 dependent, which probably involved both extrinsic and intrinsic pathways. Apaf1 may be involved in this process without elevating its gene expression. But starvation-induced germ cell apoptosis was likely mainly through extrinsic pathway. p53 was probably not responsible for stress-induced germ cell apoptosis in newt testis. The intriguing high occurrence of spermatid and sperm

  4. Phylogeography and evolution of the Red Salamander (Pseudotriton ruber).

    PubMed

    Folt, Brian; Garrison, Nicole; Guyer, Craig; Rodriguez, Juanita; Bond, Jason E

    2016-05-01

    Phylogeographic studies frequently result in the elevation of subspecific taxa to species given monophyly, or the synonymy of subspecies that are not monophyletic. However, given limited or incongruent datasets, retention of subspecies can be useful to describe hypothesized incipient species or to illustrate interesting biological phenomena driving morphological diversity. Four subspecific taxa have been used to describe largely allopatric geographic variation within the species Pseudotriton ruber, a plethodontid salamander occupying stream and spring habitats across eastern North America: P. r. vioscai occurs in lowland Coastal Plain habitats, while P. r. ruber, P. r. nitidus, and P. r. schencki occupy upland regions in and around the Appalachian Mountains. Pseudotriton ruber co-occurs through its distribution with the aposematic newt Notophthalmus viridescens, and both species are hypothesized to be part of a Müllerian mimicry complex. In this study, we sequenced regions of two mitochondrial (cytochrome b, NADH dehydrogenase subunit 2) and one single copy nuclear protein-coding gene (pro-opiomelanocortin) from individuals sampled across much of the distribution of P. ruber and then used maximum-likelihood and Bayesian phylogenetic inference to test the monophyly of subspecies, reconstruct biogeographic history, and make inferences about morphological evolution. Phylogeographic hypotheses from mitochondrial and nuclear datasets described structure among populations of P. ruber which separated Coastal Plain and upland Appalachian populations, but subspecies were not monophyletic. Biogeographic reconstruction estimated the ancestor of all populations to have occupied and initially diverged in the Coastal Plain during the Pliocene (∼3.6mya), before one lineage subsequently invaded upland areas of Appalachia. Bold bright coloration of high elevation subspecies P. r. nitidus and P. r. schencki appears to have evolved twice. We hypothesize that the Müllerian mimicry

  5. Phylogeography and evolution of the Red Salamander (Pseudotriton ruber).

    PubMed

    Folt, Brian; Garrison, Nicole; Guyer, Craig; Rodriguez, Juanita; Bond, Jason E

    2016-05-01

    Phylogeographic studies frequently result in the elevation of subspecific taxa to species given monophyly, or the synonymy of subspecies that are not monophyletic. However, given limited or incongruent datasets, retention of subspecies can be useful to describe hypothesized incipient species or to illustrate interesting biological phenomena driving morphological diversity. Four subspecific taxa have been used to describe largely allopatric geographic variation within the species Pseudotriton ruber, a plethodontid salamander occupying stream and spring habitats across eastern North America: P. r. vioscai occurs in lowland Coastal Plain habitats, while P. r. ruber, P. r. nitidus, and P. r. schencki occupy upland regions in and around the Appalachian Mountains. Pseudotriton ruber co-occurs through its distribution with the aposematic newt Notophthalmus viridescens, and both species are hypothesized to be part of a Müllerian mimicry complex. In this study, we sequenced regions of two mitochondrial (cytochrome b, NADH dehydrogenase subunit 2) and one single copy nuclear protein-coding gene (pro-opiomelanocortin) from individuals sampled across much of the distribution of P. ruber and then used maximum-likelihood and Bayesian phylogenetic inference to test the monophyly of subspecies, reconstruct biogeographic history, and make inferences about morphological evolution. Phylogeographic hypotheses from mitochondrial and nuclear datasets described structure among populations of P. ruber which separated Coastal Plain and upland Appalachian populations, but subspecies were not monophyletic. Biogeographic reconstruction estimated the ancestor of all populations to have occupied and initially diverged in the Coastal Plain during the Pliocene (∼3.6mya), before one lineage subsequently invaded upland areas of Appalachia. Bold bright coloration of high elevation subspecies P. r. nitidus and P. r. schencki appears to have evolved twice. We hypothesize that the Müllerian mimicry

  6. Predicting environmental suitability for a rare and threatened species (Lao newt, Laotriton laoensis) using validated species distribution models.

    PubMed

    Chunco, Amanda J; Phimmachak, Somphouthone; Sivongxay, Niane; Stuart, Bryan L

    2013-01-01

    The Lao newt (Laotriton laoensis) is a recently described species currently known only from northern Laos. Little is known about the species, but it is threatened as a result of overharvesting. We integrated field survey results with climate and altitude data to predict the geographic distribution of this species using the niche modeling program Maxent, and we validated these predictions by using interviews with local residents to confirm model predictions of presence and absence. The results of the validated Maxent models were then used to characterize the environmental conditions of areas predicted suitable for L. laoensis. Finally, we overlaid the resulting model with a map of current national protected areas in Laos to determine whether or not any land predicted to be suitable for this species is coincident with a national protected area. We found that both area under the curve (AUC) values and interview data provided strong support for the predictive power of these models, and we suggest that interview data could be used more widely in species distribution niche modeling. Our results further indicated that this species is mostly likely geographically restricted to high altitude regions (i.e., over 1,000 m elevation) in northern Laos and that only a minute fraction of suitable habitat is currently protected. This work thus emphasizes that increased protection efforts, including listing this species as endangered and the establishment of protected areas in the region predicted to be suitable for L. laoensis, are urgently needed.

  7. Kicking Triturus arntzeni when it's down: large-scale nuclear genetic data confirm that newts from the type locality are genetically admixed.

    PubMed

    Wielstra, B; Arntzen, J W

    2014-05-27

    We collected nuclear DNA data (52 markers) with next-generation sequencing for nine Triturus newt specimens, including the holotype and two of the paratypes of T. arntzeni, from the type locality at Vrtovać in eastern Serbia. We compare these data to a reference set composed of the four crested newt species distributed in eastern Serbia namely T. cristatus, T. dobrogicus, T. ivanbureschi and T. macedonicus to determine to which of these species the newts from the type locality of T. arntzeni should be attributed. The majority of alleles in individuals from Vrtovać is derived from T. macedonicus, but a considerable number of T. ivanbureschi alleles is also present; alleles typical for T. cristatus and T. dobrogicus are found at low frequency. Accordingly, we interpret Vrtovać as a T. macedonicus - T. ivanbureschi hybrid population, albeit not composed of F1 hybrids but of genetically admixed individuals derived through multiple generations of backcrossing. The data support the notion that the name T. arntzeni should not be applied to a species newly distinguished in T. karelinii sensu lato (to which the name T. ivanbureschi has been given). We conclude that because of the hybrid nature of the individuals from Vrtovać, the name T. arntzeni should be placed not only in the synonymy of T. macedonicus but also in the synonymy of T. ivanbureschi. In this study we demonstrate that next-generation sequencing can provide high quality data for type material with degraded DNA and therefore can play an important role in taxonomy.

  8. Toxicity and population structure of the Rough-Skinned Newt (Taricha granulosa) outside the range of an arms race with resistant predators.

    PubMed

    Hague, Michael T J; Avila, Leleña A; Hanifin, Charles T; Snedden, W Andrew; Stokes, Amber N; Brodie, Edmund D; Brodie, Edmund D

    2016-05-01

    Species interactions, and their fitness consequences, vary across the geographic range of a coevolutionary relationship. This spatial heterogeneity in reciprocal selection is predicted to generate a geographic mosaic of local adaptation, wherein coevolutionary traits are phenotypically variable from one location to the next. Under this framework, allopatric populations should lack variation in coevolutionary traits due to the absence of reciprocal selection. We examine phenotypic variation in tetrodotoxin (TTX) toxicity of the Rough-Skinned Newt (Taricha granulosa) in regions of allopatry with its TTX-resistant predator, the Common Garter Snake (Thamnophis sirtalis). In sympatry, geographic patterns of phenotypic exaggeration in toxicity and toxin-resistance are closely correlated in prey and predator, implying that reciprocal selection drives phenotypic variation in coevolutionary traits. Therefore, in allopatry with TTX-resistant predators, we expect to find uniformly low levels of newt toxicity. We characterized TTX toxicity in northwestern North America, including the Alaskan panhandle where Ta. granulosa occur in allopatry with Th. sirtalis. First, we used microsatellite markers to estimate population genetic structure and determine if any phenotypic variation in toxicity might be explained by historical divergence. We found northern populations of Ta. granulosa generally lacked population structure in a pattern consistent with northern range expansion after the Pleistocene. Next, we chose a cluster of sites in Alaska, which uniformly lacked genetic divergence, to test for phenotypic divergence in toxicity. As predicted, overall levels of newt toxicity were low; however, we also detected unexpected among- and within-population variation in toxicity. Most notably, a small number of individuals contained large doses of TTX that rival means of toxic populations in sympatry with Th. sirtalis. Phenotypic variation in toxicity, despite limited neutral genetic

  9. Kicking Triturus arntzeni when it's down: large-scale nuclear genetic data confirm that newts from the type locality are genetically admixed.

    PubMed

    Wielstra, B; Arntzen, J W

    2014-01-01

    We collected nuclear DNA data (52 markers) with next-generation sequencing for nine Triturus newt specimens, including the holotype and two of the paratypes of T. arntzeni, from the type locality at Vrtovać in eastern Serbia. We compare these data to a reference set composed of the four crested newt species distributed in eastern Serbia namely T. cristatus, T. dobrogicus, T. ivanbureschi and T. macedonicus to determine to which of these species the newts from the type locality of T. arntzeni should be attributed. The majority of alleles in individuals from Vrtovać is derived from T. macedonicus, but a considerable number of T. ivanbureschi alleles is also present; alleles typical for T. cristatus and T. dobrogicus are found at low frequency. Accordingly, we interpret Vrtovać as a T. macedonicus - T. ivanbureschi hybrid population, albeit not composed of F1 hybrids but of genetically admixed individuals derived through multiple generations of backcrossing. The data support the notion that the name T. arntzeni should not be applied to a species newly distinguished in T. karelinii sensu lato (to which the name T. ivanbureschi has been given). We conclude that because of the hybrid nature of the individuals from Vrtovać, the name T. arntzeni should be placed not only in the synonymy of T. macedonicus but also in the synonymy of T. ivanbureschi. In this study we demonstrate that next-generation sequencing can provide high quality data for type material with degraded DNA and therefore can play an important role in taxonomy. PMID:24871018

  10. Poleward kinetochore fiber movement occurs during both metaphase and anaphase-A in newt lung cell mitosis

    PubMed Central

    1992-01-01

    Microtubules in the mitotic spindles of newt lung cells were marked using local photoactivation of fluorescence. The movement of marked segments on kinetochore fibers was tracked by digital fluorescence microscopy in metaphase and anaphase and compared to the rate of chromosome movement. In metaphase, kinetochore oscillations toward and away from the poles were coupled to kinetochore fiber shortening and growth. Marked zones on the kinetochore microtubules, meanwhile, moved slowly polewards at a rate of approximately 0.5 micron/min, which identifies a slow polewards movement, or "flux," of kinetochore microtubules accompanied by depolymerization at the pole, as previously found in PtK2 cells (Mitchison, 1989b). Marks were never seen moving away from the pole, indicating that growth of the kinetochore microtubules occurs only at their kinetochore ends. In anaphase, marked zones on kinetochore microtubules also moved polewards, though at a rate slower than overall kinetochore-to-pole movement. Early in anaphase-A, microtubule depolymerization at kinetochores accounted on average for 75% of the rate of chromosome-to-pole movement, and depolymerization at the pole accounted for 25%. When chromosome-to-pole movement slowed in late anaphase, the contribution of depolymerization at the kinetochores lessened, and flux became the dominant component in some cells. Over the whole course of anaphase-A, depolymerization at kinetochores accounted on average for 63% of kinetochore fiber shortening, and flux for 37%. In some anaphase cells up to 45% of shortening resulted from the action of flux. We conclude that kinetochore microtubules change length predominantly through polymerization and depolymerization at the kinetochores during both metaphase and anaphase as the kinetochores move away from and towards the poles. Depolymerization, though not polymerization, also occurs at the pole during metaphase and anaphase, so that flux contributes to polewards chromosome movements

  11. Masters of change: seasonal plasticity in the prey-capture behavior of the Alpine newt Ichthyosaura alpestris (Salamandridae).

    PubMed

    Heiss, Egon; Aerts, Peter; Van Wassenbergh, Sam

    2013-12-01

    Transitions between aquatic and terrestrial environments are significant steps in vertebrate evolution. These transitions require major changes in many biological functions, including food uptake and transport. The Alpine newt, Ichthyosaura alpestris, is known to show a 'multiphasic lifestyle' where the adult shifts from a terrestrial to an aquatic lifestyle and then back to a terrestrial lifestyle every year as a result of its breeding activity. These transitions correspond to dramatic changes in morphology, physiology and behavior, resulting in distinct aquatic and terrestrial morphotypes. We hypothesized that these shifts go along with changes in prey-capture mechanics to maintain a sufficiently high performance in both environments. We analyzed the prey-capture kinematics in the four possible modes: aquatic strikes in the aquatic phase, terrestrial strikes in the terrestrial phase, aquatic strikes in the terrestrial phase and terrestrial strikes in the aquatic phase. A multivariate comparison detected significant kinematic differences between the phase-specific feeding modes. In both the aquatic and the terrestrial phase, I. alpestris uses a suction-feeding mechanism for capturing prey in water. By contrast, I. alpestris uses a jaw-based grasping mechanism with a kinematic profile similar to the aquatic modes for terrestrial prey-capture in its aquatic phase but an elaborate lingual-based prehension mechanism to capture terrestrial prey in the terrestrial phase. These results exhibit a so-far unknown amount of behavioral plasticity in prey-capture behavior that is tuned to the seasonal demands of performance, and exemplify functional mechanisms behind aquatic-terrestrial transitions in vertebrates.

  12. Liver histology and ultrastructure of the Italian newt (Lissotriton italicus): normal structure and modifications after acute exposure to nonylphenol ethoxylates.

    PubMed

    Bernabò, Ilaria; Biasone, Patrizia; Macirella, Rachele; Tripepi, Sandro; Brunelli, Elvira

    2014-12-01

    We examined, from a morphological and ultrastructural point of view, the liver of the Italian newt (Lissotriton italicus), under basal conditions and after exposure to nonylphenol ethoxylates (NPEs). Nonylphenol ethoxylates are surfactants widely used in a variety of industrial and agricultural processes that may pose a significant risk to aquatic fauna. NPEs, and their degradation intermediates, are known to affect reproductive biology acting as endocrine disruptors; besides estrogenic effects, nonylphenolic compounds may induce organ toxicity, particularly in liver and gonads. We investigated the effects of a nonylphenol ethoxylate (NPE10-ETO) on L. italicus liver using two low concentrations, consistent with the environmental concentrations. For this purpose, animals were exposed to nominal concentrations of 50 and 100 μg/L in a short-term experiment (96 h). A morpho-functional analysis was performed in order to investigate the amphibian responses to NPEs thus contributing to elucidate other potential mode of action of these compounds; indeed very little attention has been dedicated to amphibians though they are often exposed to such contaminants in aquatic ecosystems. Pathological alterations on liver histology and ultrastructure were observed at both tested concentrations; the main effects recorded were: increase of intercellular spaces, accumulation of large lipid droplets, increase in melanin content, and a degeneration phenomenon. We also detected, through confocal analysis, the induction of caspase-3, a key mediator of apoptosis, and an up-regulation of cytochrome P450-1A. By using both ultrastructural and a morpho-functional approach, we found that a short-term exposure to NPEs negatively affected the amphibian liver.

  13. Egg transport in the coelom of the newt cynops pyrrhogaster. I. The ovulated egg is transported to the ostium by the ciliary movement of coelomic epithelial cells.

    PubMed

    Yamahama, Yumi; Onitake, Kazuo

    2002-08-01

    We investigated the mechanism of egg transport in the newt not only by inserting various conditioned eggs into the recipient's body but also by placing them on the coelomic epithelia of the opened body cavity in the adult female newt. Most of the inserted coelomic eggs were oviposited, while 4 of 14 inserted de-jellied uterine eggs and 3 of 10 inserted de-jellied fertilized eggs were oviposited. The coelomic eggs placed on the coelomic epithelia were transported toward the ostium and entered the ostium. The de-jellied uterine eggs and the de-jellied fertilized eggs were transported to the ostium as well. Of all the eggs examined, the coelomic egg was transported the fastest. The transport speeds of coelomic eggs treated with periodic acid and the speed of boiled coelomic eggs were less than those of untreated coelomic eggs. In contrast, the transport speeds of coelomic eggs treated with trypsin and the speed of coelomic eggs removed from their vitelline envelopes (naked eggs) were faster than those of untreated coelomic eggs. Other experiments were carried out in order to ascertain the dependence of sexual activity on egg transport. The speed of coelomic egg transport in artificially sexually activated females was faster than in sexually inactive females, although the ciliary movement could always be observed in both sexually active females and sexually inactive females. This suggests that the speed of egg transport on the coelomic epithelia is controlled by the sexual activity of the female. PMID:12193806

  14. Single Nucleotide Polymorphisms Reveal Genetic Structuring of the Carpathian Newt and Provide Evidence of Interspecific Gene Flow in the Nuclear Genome

    PubMed Central

    Zieliński, Piotr; Dudek, Katarzyna; Stuglik, Michał Tadeusz; Liana, Marcin; Babik, Wiesław

    2014-01-01

    Genetic variation within species is commonly structured in a hierarchical manner which may result from superimposition of processes acting at different spatial and temporal scales. In organisms of limited dispersal ability, signatures of past subdivision are detectable for a long time. Studies of contemporary genetic structure in such taxa inform about the history of isolation, range changes and local admixture resulting from geographically restricted hybridization with related species. Here we use a set of 139 transcriptome-derived, unlinked nuclear single nucleotide polymorphisms (SNP) to assess the genetic structure of the Carpathian newt (Lissotriton montandoni, Lm) and introgression from its congener, the smooth newt (L. vulgaris, Lv). Two substantially differentiated groups of Lm populations likely originated from separate refugia, both located in the Eastern Carpathians. The colonization of the present range in north-western and south-western directions was accompanied by a modest loss of variation; admixture between the two groups has occurred in the middle of the Eastern Carpathians. Local, apparently recent introgression of Lv alleles into several Lm populations was detected, demonstrating increased power for admixture detection in comparison to a previous study based on a limited number of microsatellite markers. The level of introgression was higher in Lm populations classified as admixed than in syntopic populations. We discuss the possible causes and propose further tests to distinguish between alternatives. Several outlier loci were identified in tests of interspecific differentiation, suggesting genomic heterogeneity of gene flow between species. PMID:24820116

  15. Increased frequency and severity of developmental deformities in rough-skinned newt (Taricha granulosa) embryos exposed to road deicing salts (NaCl & MgCl2).

    PubMed

    Hopkins, Gareth R; French, Susannah S; Brodie, Edmund D

    2013-02-01

    Road-side aquatic ecosystems in North America are annually polluted with millions of tons of road deicing salts, which threaten the survival of amphibians which live and breed in these habitats. While much is known of the effects of NaCl, little is known of the second most-commonly used deicer, MgCl(2), which is now used exclusively in parts of the continent. Here we report that environmentally relevant concentrations of both NaCl and MgCl(2) cause increased incidence of developmental deformities in rough-skinned newt hatchlings that developed embryonically in these salts. In addition, we provide some of the first quantification of severity of different deformities, and reveal that increased salt concentrations increase both deformity frequency and severity. Our work contributes to the growing body of literature that suggests salamanders and newts are particularly vulnerable to salt, and that the emerging pollutant, MgCl(2) is comparable in its effects to the more traditionally-used NaCl.

  16. Effects of ammonium nitrate exposure and water acidification on the dwarf newt: the protective effect of oviposition behaviour on embryonic survival.

    PubMed

    Ortiz-Santaliestra, Manuel E; Marco, Adolfo; Fernández-Benéitez, María José; Lizana, Miguel

    2007-12-30

    Embryonic mortality in many aquatic animals, including most amphibian species, is usually very high. In addition to mechanical and chemical defences, some species have developed behavioural patterns that can increase egg survival. For example, females of some newt species protect their eggs by wrapping them in leaves of aquatic plants. We have studied the effects of ammonium nitrate (nominal concentration of 90.3 mg N-NO(3)NH(4)/L) and water acidification (pH 4-5) on egg wrapping behaviour of the dwarf newt, Triturus pygmaeus, and on whether this specific behaviour may protect embryos from contamination. Although either ammonium nitrate or low pH did not inhibit oviposition, the mean percentage of eggs that were wrapped by the females was significantly lower at low pH than in controls. In order to assess the potential effects of oviposition behaviour on embryonic survival, we exposed simultaneously wrapped and unwrapped eggs to ammonium nitrate and acid pH during their development. After 25 days of exposure, ammonium nitrate reduced length and developmental stage at eclosion of the exposed individuals, regardless of whether they were wrapped or unwrapped. The fertilizer caused a significantly higher mortality in unwrapped than wrapped eggs. The potential impact of water pollution on amphibians in the field may include not only direct effects on embryonic and larval survival but also alteration of breeding behaviours, which may reduce reproductive success and ultimately affect population's condition. PMID:17959261

  17. Study of the genotoxic activity of five chlorinated propanones using the SOS chromotest, the Ames-fluctuation test and the newt micronucleus test.

    PubMed

    Le Curieux, F; Marzin, D; Erb, F

    1994-11-01

    Three short-term assays (the SOS chromotest, the Ames-fluctuation test and the newt micronucleus test) were carried out to evaluate the genotoxicity of five chlorinated propanones identified in several chlorinated waters (monochloropropanone, 1,1-dichloropropanone, 1,3-dichloropropanone, 1,1,1-trichloropropanone and 1,1,3-trichloropropanone). In the SOS chromotest, all the compounds except monochloropropanone were found to induce primary DNA damage in Escherichia coli. With the fluctuation test, all five chloropropanones showed mutagenic activity on Salmonella typhimurium strain TA100. The newt micronucleus assay detected a clastogenic effect on the peripheral blood erythrocytes of Pleurodeles waltl larvae only for 1,3-dichloropropanone and 1,1,3-trichloropropanone. Moreover, two structure-activity relationships are noticeable: (1) chloropropanones with chlorine substituents on both carbon positions (1,3-DCP and 1,1,3-TCP) are by far more genotoxic than chloropropanones substituted only on one carbon position (1,1-DCP and 1,1,1-TCP); (2) the increase of the number of chlorine substituents decreases the mutagenic activity (fluctuation test) of the chlorinated propanones studied.

  18. Modeling of impurity spectroscopy in the divertor and SOL of DIII-D using the 1D multifluid model NEWT1D

    SciTech Connect

    West, W.P.; Evans, T.E.; Brooks, N.H.

    1996-10-01

    NEWT1D, a one dimensional multifluid model of the scrape-off layer and divertor plasma, has been used to model the plasma including the distribution of carbon ionization states in the SOL and divertor of ELMing H-mode at two injected power levels in DIII-D. Comparison of the code predictions to the measured divertor and scrape-off layer (SOL) plasma density and temperature shows good agreement. Comparison of the predicted line emissions to the spectroscopic data suggests that physically sputtered carbon from the strike point is not transported up the flux tube; a distributed source of carbon a few centimeters up the flux tube is required to achieve reasonable agreement.

  19. An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids.

    PubMed

    Marjanović, David; Witzmann, Florian

    2015-01-01

    We describe an Oligocene newt specimen from western Germany that has gone practically unnoticed in the literature despite having been housed in the Museum für Naturkunde (Berlin) for a century. It is referable to the coeval Chelotriton, but is unusually peramorphic; for many characters it is more peramorphic than all other caudates or even all other lissamphibians. Most noticeable are the position of the jaw joints far caudal to the occiput, the honeycombed sculpture on the maxilla, and the possible presence of a septomaxilla (which would be unique among salamandrids). Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species. A phylogenetic analysis of nonmolecular characters of Salamandridae, far larger than all predecessors, confirms the referral to Chelotriton. It further loosely associates the Oligocene Archaeotriton and the Miocene Carpathotriton with the extant Lissotriton, though the former may alternatively lie outside Pleurodelinae altogether. The Miocene? I. randeckensis may not belong to the extant Ichthyosaura. The Miocene "Triturus" roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins. The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses. We would like to urge neontologists working on salamandrids to pay renewed attention to the skeleton, not limited to the skull, as a source of diagnostic and phylogenetically informative characters. PMID:26421432

  20. Neuronal regeneration in the newt: a model to study the partly reconstruction of the neural tissue in real and simulated weightles sness

    NASA Astrophysics Data System (ADS)

    Anton, H.; Grigoryan, E.; Mitashov, V.

    The micro -"g" effect on nervous tissue regeneration in newts has been investigated by our group for many years. It has been performed in real and in simulated microgravity with a clinostat. During limb regeneration the motor - and sensory nerves regrow perfectly within the newly formed limb. Like in `1g' conditions they are responsible for the initiation of blastema formation and continuity of g owth andr differentiation. Except for a general acceleration of growth and differentiation processes no differences became visible. Tail regeneration, which is perfectly regulated in newts during their whole life, includes the restoration of the spinal cord and dorsal root ganglia. They follow or initiate an accelerated growth. Up to the present the cellular derivation of the sensory neurones within the regenerate has not yet been clarified. But growth acceleration comprises the whole nervous system. That means a totally new formation of the sensory connection from the periphery to the whole spinal cord. Regeneration must be initiated by the outgrowth of nerve fibres into the wound area. This may be performed by the remaining cut sensory fibres of the last stump segment and should be followed by the differentiation of undifferentiated cells of neural crest origin nearby the amputation area. Such cells are present in the form of meningeal cells which are the origin of mantle and Schwann cells too. Corresponding to the well proved growth acceleration of lens, retina, connective tissue, muscle and skin, the real and simulated microgravity affects the nervous system in the same manner. Tissues and organs of adult organisms have no chance to remain unaffected by the microgravity effect. We try to find the trigger which initiates the accelerated proliferation of the stem cells of sensory neurons, mantle and sheath cells under micro-"g" conditions.

  1. An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids

    PubMed Central

    Marjanović, David; Witzmann, Florian

    2015-01-01

    We describe an Oligocene newt specimen from western Germany that has gone practically unnoticed in the literature despite having been housed in the Museum für Naturkunde (Berlin) for a century. It is referable to the coeval Chelotriton, but is unusually peramorphic; for many characters it is more peramorphic than all other caudates or even all other lissamphibians. Most noticeable are the position of the jaw joints far caudal to the occiput, the honeycombed sculpture on the maxilla, and the possible presence of a septomaxilla (which would be unique among salamandrids). Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species. A phylogenetic analysis of nonmolecular characters of Salamandridae, far larger than all predecessors, confirms the referral to Chelotriton. It further loosely associates the Oligocene Archaeotriton and the Miocene Carpathotriton with the extant Lissotriton, though the former may alternatively lie outside Pleurodelinae altogether. The Miocene? I. randeckensis may not belong to the extant Ichthyosaura. The Miocene “Triturus” roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins. The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses. We would like to urge neontologists working on salamandrids to pay renewed attention to the skeleton, not limited to the skull, as a source of diagnostic and phylogenetically informative characters. PMID:26421432

  2. Acute stress increases the synthesis of 7α-hydroxypregnenolone, a new key neurosteroid stimulating locomotor activity, through corticosterone action in newts.

    PubMed

    Haraguchi, Shogo; Koyama, Teppei; Hasunuma, Itaru; Okuyama, Shin-ichiro; Ubuka, Takayoshi; Kikuyama, Sakae; Do Rego, Jean-Luc; Vaudry, Hubert; Tsutsui, Kazuyoshi

    2012-02-01

    7α-Hydroxypregnenolone (7α-OH PREG) is a newly identified bioactive neurosteroid stimulating locomotor activity in the brain of newt, a wild animal, which serves as an excellent model to investigate the biosynthesis and biological action of neurosteroids. Here, we show that acute stress increases 7α-OH PREG synthesis in the dorsomedial hypothalamus (DMH) through corticosterone (CORT) action in newts. A 30-min restraint stress increased 7α-OH PREG synthesis in the brain tissue concomitant with the increase in plasma CORT concentrations. A 30-min restraint stress also increased the expression of cytochrome P450(7α) (CYP7B), the steroidogenic enzyme of 7α-OH PREG formation, in the DMH. Decreasing plasma CORT concentrations by hypophysectomy or trilostane administration decreased 7α-OH PREG synthesis in the diencephalon, whereas administration of CORT to these animals increased 7α-OH PREG synthesis. Glucocorticoid receptor was present in DMH neurons expressing CYP7B. Thus, CORT appears to act directly on DMH neurons to increase 7α-OH PREG synthesis. We further investigated the biological action of 7α-OH PREG in the brain under stress. A 30-min restraint stress or central administration of 7α-OH PREG increased serotonin concentrations in the diencephalon. Double immunolabeling further showed colocalization of CYP7B and serotonin in the DMH. These results indicate that acute stress increases the synthesis of 7α-OH PREG via CORT action in the DMH, and 7α-OH PREG activates serotonergic neurons in the DMH that may coordinate behavioral responses to stress. This is the first demonstration of neurosteroid biosynthesis regulated by peripheral steroid hormone and of neurosteroid action in the brain under stress in any vertebrate class.

  3. An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids.

    PubMed

    Marjanović, David; Witzmann, Florian

    2015-01-01

    We describe an Oligocene newt specimen from western Germany that has gone practically unnoticed in the literature despite having been housed in the Museum für Naturkunde (Berlin) for a century. It is referable to the coeval Chelotriton, but is unusually peramorphic; for many characters it is more peramorphic than all other caudates or even all other lissamphibians. Most noticeable are the position of the jaw joints far caudal to the occiput, the honeycombed sculpture on the maxilla, and the possible presence of a septomaxilla (which would be unique among salamandrids). Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species. A phylogenetic analysis of nonmolecular characters of Salamandridae, far larger than all predecessors, confirms the referral to Chelotriton. It further loosely associates the Oligocene Archaeotriton and the Miocene Carpathotriton with the extant Lissotriton, though the former may alternatively lie outside Pleurodelinae altogether. The Miocene? I. randeckensis may not belong to the extant Ichthyosaura. The Miocene "Triturus" roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins. The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses. We would like to urge neontologists working on salamandrids to pay renewed attention to the skeleton, not limited to the skull, as a source of diagnostic and phylogenetically informative characters.

  4. Androgen receptor (AR), estrogen receptor-alpha (ER-α) and estrogen receptor-beta (ER-β) expression in the testis of the newt, Triturus marmoratus marmoratus during the annual cycle

    PubMed Central

    ARENAS, M. I.; ROYUELA, M.; LOBO, M. V. T.; ALFARO, J. M.; FRAILE, B.; PANIAGUA, R.

    2001-01-01

    Expression of androgen receptor (AR), estrogen receptor alpha (ER-α) and estrogen receptor beta (ER-β) in the testis of the marbled newt (Triturus marmoratus marmoratus) was investigated, with special attention to changes during the annual testicular cycle, using light microscopy immunohistochemistry and Western blot analysis. Primordial germ cells, primary and secondary spermatogonia and spermatocytes showed a positive reaction to the 3 receptor antibodies during the annual reproductive cycle. Follicular cells were positive to AR, ER-α and ER-β during the spermiogenesis and quiescence periods in the glandular tissue. Interstitial cells showed reactivity to AR, ER-α and ER-β in the spermiogenesis and the quiescence periods, and presented no labelling to these receptors in the proliferative period. These findings suggest that, as in mammals, there is an androgen-estrogen regulation of the function and development of the newt testis. PMID:11693307

  5. Marked genetic structuring and extreme dispersal limitation in the Pyrenean brook newt Calotriton asper (Amphibia: Salamandridae) revealed by genome-wide AFLP but not mtDNA.

    PubMed

    Milá, Borja; Carranza, Salvador; Guillaume, Olivier; Clobert, Jean

    2010-01-01

    Direct estimation of dispersal rates at large geographic scales can be technically and logistically challenging, especially in small animals of low vagility like amphibians. The use of molecular markers to reveal patterns of genetic structure provides an indirect way to infer dispersal rates and patterns of recent and historical gene flow among populations. Here, we use mitochondrial DNA (mtDNA) sequence data and genome-wide amplified fragment length polymorphism markers to examine population structure in the Pyrenean brook newt (Calotriton asper) across four main drainages in the French Pyrenees. mtDNA sequence data (2040 bp) revealed three phylogroups shallowly differentiated and with low genetic diversity. In sharp contrast, variation in 382 amplified fragment length polymorphism loci was high and revealed a clear pattern of isolation by distance consistent with long-term restriction of gene flow at three spatial scales: (i) among all four main drainages, (ii) between sites within drainages, and (iii) even between adjacent populations separated by less than 4 km. The high pairwise F(ST) values between localities across numerous loci, together with the high frequency of fixed alleles in several populations, suggests a combination of marked geographic isolation, small population sizes and very limited dispersal in C. asper. The contrasting lack of variation detected in mtDNA sequence data is intriguing and underscores the importance of multilocus approaches to detect true patterns of gene flow in natural populations of amphibians.

  6. Production of otoconia in the endolymphatic sac in the Japanese red-bellied newt, Cynops pyrrhogaster: light and transmission electron microscopic study

    NASA Technical Reports Server (NTRS)

    Gao, W.; Wiederhold, M. L.; Hejl, R.

    1998-01-01

    The formation of otoconia in the endolymphatic sac (ES) of the larval newt, Cynops pyrrhogaster, has been studied by light and transmission electron microscopy. Some of the epithelial cells of the ES contain an abundance of swollen vesicles, Golgi complexes, rough endoplasmic reticula and ribosomes at the late larval stages 50 and 51, approximately 26-30 days after eggs are laid. Five days later, at stage 52, crystals are present in the vacuoles between the epithelial cells. Serial sections indicate that these vacuoles actually form small canals which lie in the wall and join the lumen of the ES. Reconstruction of the ES shows that several canals are contained in the ES wall. At stage 56, about 72 days after eggs are laid, a large number of otoconia are present in the ES lumen, while the otoconia disappear from the canals. It appears that the otoconia are first produced in the canals and then released to the lumen. Some epithelial cells of the ES are thought to expel the organic and inorganic material to the canals to form the otoconia in situ. The process of formation of the otoconia in the ES is discussed.

  7. A revised taxonomy of crested newts in the Triturus karelinii group (Amphibia: Caudata: Salamandridae), with the description of a new species.

    PubMed

    Wielstra, B; Litvinchuk, S N; Naumov, B; Tzankov, N; Arntzen, J W

    2013-01-01

    We present a taxonomic revision of the crested newt Triturus karelinii sensu lato. Based on the presence of discrete nuclear DNA gene pools, deep genetic divergence of mitochondrial and nuclear DNA, and no indication of gene flow, we interpret this taxon as comprising two species: one covering the southern Caspian Sea shore, the Caucasus and the Crimea, i.e. the eastern part of the total range and another covering northern Asiatic Turkey and western Asiatic Turkey plus the southeastern Balkan Peninsula, i.e. the central and western part of the total range. We acknowledge that the central/western species should likely be further subdivided into a central and a western taxon, but we prefer to await a more detailed genetic analysis of the putative contact zone, positioned in northwestern Asiatic Turkey. The name T. karelinii (Strauch, 1870) applies to the eastern species as the type locality is positioned along the coast of the Gulf of Gorgan, Iran. The name T. arntzeni has been applied to the central/western species with Vrtovać, Serbia as the type locality. We show that not T. karelinii sensu lato but T. macedonicus occurs at Vrtovać. Hence, the name T. arntzeni Litvinchuk, Borkin, Dzukić and Kalezić, 1999 (in Litvinchuk et al., 1999) is a junior synonym of T. macedonicus (Karaman, 1922) and should not be used for the central/western species. We propose the name T. ivanbureschi sp. nov. for the central/western species and provide a formal species description.

  8. Corticosterone suppresses vasotocin-enhanced clasping behavior in male rough-skinned newts by novel mechanisms interfering with V1a receptor availability and receptor-mediated endocytosis.

    PubMed

    Davis, Audrey; Abraham, Emily; McEvoy, Erin; Sonnenfeld, Sarah; Lewis, Christine; Hubbard, Catherine S; Dolence, E Kurt; Rose, James D; Coddington, Emma

    2015-03-01

    In rough-skinned newts, Taricha granulosa, exposure to an acute stressor results in the rapid release of corticosterone (CORT), which suppresses the ability of vasotocin (VT) to enhance clasping behavior. CORT also suppresses VT-induced spontaneous activity and sensory responsiveness of clasp-controlling neurons in the rostromedial reticular formation (Rf). The cellular mechanisms underlying this interaction remain unclear. We hypothesized that CORT blocks VT-enhanced clasping by interfering with V1a receptor availability and/or VT-induced endocytosis. We administered a physiologically active fluorescent VT conjugated to Oregon Green (VT-OG) to the fourth ventricle 9 min after an intraperitoneal injection of CORT (0, 10, 40 μg/0.1mL amphibian Ringers). The brains were collected 30 min post-VT-OG, fixed, and imaged with confocal microscopy. CORT diminished the number of endocytosed vesicles, percent area containing VT-OG, sum intensity of VT-OG, and the amount of VT-V1a within each vesicle; indicating that CORT was interfering with V1a receptor availability and VT-V1a receptor-mediated endocytosis. CORT actions were brain location-specific and season-dependent in a manner that is consistent with the natural and context-dependent expression of clasping behavior. Furthermore, the sensitivity of the Rf to CORT was much higher in animals during the breeding season, arguing for ethologically appropriate seasonal variation in CORT's ability to prevent VT-induced endocytosis. Our data are consistent with the time course and interaction effects of CORT and VT on clasping behavior and neurophysiology. CORT interference with VT-induced endocytosis may be a common mechanism employed by hormones across taxa for mediating rapid context- and season-specific behavioral responses.

  9. [The comparative characteristics of crystalline lens and limb regeneration in newts operated on before and after the completion of an orbital space flight].

    PubMed

    Tuchkova, S Ia; Brushlinskaia, N V; Grigorian, E N; Mitashov, V I

    1994-01-01

    It has been already established that a tendency towards synchronization and acceleration of the forelimb and lens regeneration is observed in Pleurodeles waltlii under the effect of space flight factors. Here we present the results obtained after 16-day space flight of two groups of newts. In animals of group I forelimbs were amputated and lenses were removed 14 and 7 days before the space flight, respectively. Intact animals of group II were operated on the day of the sputnik landing. Regenerates of the flight and corresponding control animals were fixed at the same time after the operation. For evaluation of the regeneration rate morphological criteria were used: morphological stages of regeneration were compared in the experiment and the control. For quantitative assay of the regeneration rate we determined the index of nuclei labelled with 3H-thymidine in the blastema and lens rudiment cells and used morphometry of the lens regenerates. Acceleration of forelimb and lens regeneration was observed in both groups of animals. In group II more than two-fold increase of the index of labelled nuclei was found in the blastema cells at the comparable stages of development. The size of lens regenerates in flight groups I and II exceeded reliably those in the control animals. The results obtained suggest a prolonged effect of the space flight factors on forelimb and lens regeneration. Under the conditions of space flight the lens regenerates reached more advanced stages of regeneration, as compared with the control animals operated after the space flight. These results also suggest acceleration of regeneration in lower vertebrates. PMID:7858470

  10. Effects of light on the cytotoxicity and genotoxicity of benzo(a)pyrene and an oil refinery effluent in the newt

    SciTech Connect

    Fernandez, M.; l`Haridon, J.

    1994-12-31

    The genotoxicity and/or toxicity of benzo(a)pyrene (BaP) were evaluated under different lighting conditions in larvae and embryos of the newt Pleurodeles waltl. Visible light alone, UVA alone, or BaP alone had no toxic effects on the larvae. Conversely, toxic effects were observed in animals exposed to BaP + daylight, or BaP + UVA. The genotoxicity of BaP (50 ppb) was halved by its previous exposure to UVA, and was abolished at the lowest concentration (12.5 ppb). In other experiments, the larvae were exposed alternatively to BaP or Irr BaP (18 hours in dark) and UVA (6 hr in water), every day for 8 days. All animals that had accumulated non-irradiated BaP (50 ppb) showed signs of severe toxicity, and 90% died before the end of the test. On the other hand, irradiated BaP (50 ppb) was a 4-fold less toxic and half as genotoxic as non-irradiated BaP. In addition, exposure of the animals to UVA alone for 4 days prior to treatment with BaP did not affect the genotoxicity or toxicity of this hydrocarbon. In the dark, the embryotoxicity of BaP was markedly attenuated by the presence of the jelly coats. Although UVA alone did not affect growth of the embryos, the toxicity of BaP was enhanced by the combined action of the two agents together or in succession (BaP + UVA or BaP then UVA). Larvae were treated with an oil refinery effluent (EF). At 125 ml/l, EF was not found to be genotoxic in the dark. However, in animals exposed to both EF and UVA, there was a progressive increase in level of micronucleated erythrocytes with increasing duration of daily exposure to UVA. Moreover, the genotoxic potential of irradiated EF + UVA was systematically below that of non-irradiated EF + UVA for all durations of exposure to ultraviolet light. Irradiation of this type of effluent might help reduce its harmful effects on aquatic species. Our results also suggest that metabolic activation is not necessary for hydrocarbons to induce toxic effects. 51 refs., 5 tabs., 3 figs.

  11. Micronuclei in red blood cells of the newt Pleurodeles waltl after treatment with benzo(a)pyrene: dependence on dose, length of exposure, posttreatment time, and uptake of the drug

    SciTech Connect

    Grinfeld, S.; Jaylet, A.; Siboulet, R.; Deparis, P.; Chouroulinkov, I.

    1986-01-01

    Aquatic larvae of the newt Pleurodeles waltl were exposed to different concentrations of benzo(a)pyrene (BaP) for various lengths of time. Frequencies of micronuclei in circulating erythrocytes were determined at different times after termination of the treatment. The incidence of micronuclei in larvae kept for 8 days in BaP-containing water displayed a marked increase with dose up to 0.075 ppm and a more gradual one with higher doses, reaching 158 per 1000 at 0.75 ppm. The lowest dose at which a significant increase could be discerned was 0.01 ppm. Short periods of exposure, less than 2 days, did not result in a marked increase in micronuclei. Uptake and release was studied with tritiated BaP. Larvae concentrated BaP rapidly, attaining maximal levels after 12 hr. Radioactive larvae placed in regularly renewed noncontaminated water lost 99% of the label after 100 hr. It is concluded that pleurodele larvae are a promising model for the detection of genotoxic activity in the aquatic environment.

  12. A molecular assessment of phylogenetic relationships and lineage accumulation rates within the family Salamandridae (Amphibia, Caudata).

    PubMed

    Weisrock, David W; Papenfuss, Theodore J; Macey, J Robert; Litvinchuk, Spartak N; Polymeni, Rosa; Ugurtas, Ismail H; Zhao, Ermi; Jowkar, Houman; Larson, Allan

    2006-11-01

    We examine phylogenetic relationships among salamanders of the family Salamandridae using approximately 2700 bases of new mtDNA sequence data (the tRNALeu, ND1, tRNAIle, tRNAGln, tRNAMet, ND2, tRNATrp, tRNAAla, tRNAAsn, tRNACys, tRNATyr, and COI genes and the origin for light-strand replication) collected from 96 individuals representing 61 of the 66 recognized salamandrid species and outgroups. Phylogenetic analyses using maximum parsimony and Bayesian analysis are performed on the new data alone and combined with previously reported sequences from other parts of the mitochondrial genome. The basal phylogenetic split is a polytomy of lineages ancestral to (1) the Italian newt Salamandrina terdigitata, (2) a strongly supported clade comprising the "true" salamanders (genera Chioglossa, Mertensiella, Lyciasalamandra, and Salamandra), and (3) a strongly supported clade comprising all newts except S. terdigitata. Strongly supported clades within the true salamanders include monophyly of each genus and grouping Chioglossa and Mertensiella as the sister taxon to a clade comprising Lyciasalamandra and Salamandra. Among newts, genera Echinotriton, Pleurodeles, and Tylototriton form a strongly supported clade whose sister taxon comprises the genera Calotriton, Cynops, Euproctus, Neurergus, Notophthalmus, Pachytriton, Paramesotriton, Taricha, and Triturus. Our results strongly support monophyly of all polytypic newt genera except Paramesotriton and Triturus, which appear paraphyletic, and Calotriton, for which only one of the two species is sampled. Other well-supported clades within newts include (1) Asian genera Cynops, Pachytriton, and Paramesotriton, (2) North American genera Notophthalmus and Taricha, (3) the Triturus vulgaris species group, and (4) the Triturus cristatus species group; some additional groupings appear strong in Bayesian but not parsimony analyses. Rates of lineage accumulation through time are evaluated using this nearly comprehensive sampling of

  13. Phylogeny and biogeography of the family Salamandridae (Amphibia: Caudata) inferred from complete mitochondrial genomes.

    PubMed

    Zhang, Peng; Papenfuss, Theodore J; Wake, Marvalee H; Qu, Lianghu; Wake, David B

    2008-11-01

    Phylogenetic relationships of members of the salamander family Salamandridae were examined using complete mitochondrial genomes collected from 42 species representing all 20 salamandrid genera and five outgroup taxa. Weighted maximum parsimony, partitioned maximum likelihood, and partitioned Bayesian approaches all produce an identical, well-resolved phylogeny; most branches are strongly supported with greater than 90% bootstrap values and 1.0 Bayesian posterior probabilities. Our results support recent taxonomic changes in finding the traditional genera Mertensiella, Euproctus, and Triturus to be non-monophyletic species assemblages. We successfully resolved the current polytomy at the base of the salamandrid tree: the Italian newt genus Salamandrina is sister to all remaining salamandrids. Beyond Salamandrina, a clade comprising all remaining newts is separated from a clade containing the true salamanders. Among these newts, the branching orders of well-supported clades are: primitive newts (Echinotriton, Pleurodeles, and Tylototriton), New World newts (Notophthalmus-Taricha), Corsica-Sardinia newts (Euproctus), and modern European newts (Calotriton, Lissotriton, Mesotriton, Neurergus, Ommatotriton, and Triturus) plus modern Asian newts (Cynops, Pachytriton, and Paramesotriton).Two alternative sets of calibration points and two Bayesian dating methods (BEAST and MultiDivTime) were used to estimate timescales for salamandrid evolution. The estimation difference by dating methods is slight and we propose two sets of timescales based on different calibration choices. The two timescales suggest that the initial diversification of extant salamandrids took place in Europe about 97 or 69Ma. North American salamandrids were derived from their European ancestors by dispersal through North Atlantic Land Bridges in the Late Cretaceous ( approximately 69Ma) or Middle Eocene ( approximately 43Ma). Ancestors of Asian salamandrids most probably dispersed to the eastern Asia

  14. Differential RNA-binding activity of the hnRNP G protein correlated with the sex genotype in the amphibian oocyte

    PubMed Central

    Kanhoush, Rasha; Praseuth, Danièle; Perrin, Caroline; Chardard, Dominique; Vinh, Joëlle; Penrad-Mobayed, May

    2011-01-01

    A proteomic approach has enabled the identification of an orthologue of the splicing factor hnRNP G in the amphibians Xenopus tropicalis, Ambystoma mexicanum, Notophthalmus viridescens and Pleurodeles walt, which shows a specific RNA-binding affinity similar to that of the human hnRN G protein. Three isoforms of this protein with a differential binding affinity for a specific RNA probe were identified in the P. walt oocyte. In situ hybridization to lampbrush chromosomes of P. waltl revealed the presence of a family of hnRNP G genes, which were mapped on the Z and W chromosomes and one autosome. This indicates that the isoforms identified in this study are possibly encoded by a gene family linked to the evolution of sex chromosomes similarly to the hnRNP G/RBMX gene family in mammals. PMID:21278421

  15. Amphibians have immunoglobulins similar to ancestral IgD and IgA from Amniotes.

    PubMed

    Estevez, Olivia; Garet, Elina; Olivieri, David; Gambón-Deza, Francisco

    2016-01-01

    We studied the immunoglobulin genes from either the genomes or RNAs of amphibians. In particular, we obtained data from one frog genome (Nanorana parkeri) and three transcriptomes of the Caudata order (Andrias davidianus, Notophthalmus viridescens and Cynops pyrrhogaster). Apart from the immunoglobulins IgM and IgY previously described, we identified several IgD related immunoglobulins. The species N. parkeri, N. viridescens and C. pyrrhogaster have two IgD genes, while Andrias davidianus has three such genes. The three Caudata species have long IgD immunoglobulins similar to IgD of reptiles, and could be an ancient relic from the common ancestor of IgD of all mammals and reptiles. We also found two IgA isotypes. The results suggest that one of the IgA may be the ancestor of IgA in crocodiles and birds, while the other could be the ancestor IgA found in mammals. These results provide information that could help understand the evolution of immunoglobulins in terrestrial vertebrates.

  16. Predator perception of Batesian mimicry and conspicuousness in a salamander.

    PubMed

    Kraemer, Andrew C; Adams, Dean C

    2014-04-01

    In Batesian mimicry a palatable mimic deceives predators by resembling an unpalatable model. The evolution of Batesian mimicry relies on the visual capabilities of the potential predators, as prey detection provides the selective force driving evolutionary change. We compared the visual capabilities of several potential predators to test predictions stemming from the hypothesis of Batesian mimicry between two salamanders: the model species Notophthalmus viridescens, and polymorphic mimic, Plethodon cinereus. First, we found mimicry to be restricted to coloration, but not brightness. Second, only bird predators appeared able to discriminate between the colors of models and nonmimic P. cinereus. Third, estimates of salamander conspicuousness were background dependent, corresponding to predictions only for backgrounds against which salamanders are most active. These results support the hypothesis that birds influence the evolution of Batesian mimicry in P. cinereus, as they are the only group examined capable of differentiating N. viridescens and nonmimetic P. cinereus. Additionally, patterns of conspicuousness suggest that selection from predators may drive the evolution of conspicuousness in this system. This study confirms the expectation that the visual abilities of predators may influence the evolution of Batesian mimicry, but the role of conspicuousness may be more complex than previously thought.

  17. Synonymy of Katianna coeruleocephala Handschin, 1920 (Collembola: Katiannidae) with Bourletiella viridescens (Bourletiellidae).

    PubMed

    Greenslade, Penelope

    2016-01-01

    Katianna coeruleocephala was described by Handschin in 1920 from Poespo, Java. It was collected in December, 1896 by Dr. Zehntner with the collecting details given as rotten "Louv" (leaves?) from live orchard. Handschin (1920) labelled his figures of the species (p. 146) as Katianna coerulescephala but the first spelling of the species name (p. 145) has priority. Katianna coeruleocephala has never been recollected. The only mention of the species in the literature since 1920 has been by Suhardjono (1989) in a check list for Indonesia and Suhardjono (2012) who listed it as present on Java and provided the main characteristics of the genus Katianna Börner, 1923. She stated it was a "new" (translate as endemic?) species in Java with a preferred habitat in cold and damp litter but no comment was made on the taxonomic status of the Indonesian species. PMID:27395532

  18. The new ATLAS track reconstruction (NEWT)

    NASA Astrophysics Data System (ADS)

    Cornelissen, T.; Elsing, M.; Gavrilenko, I.; Liebig, W.; Moyse, E.; Salzburger, A.

    2008-07-01

    The track reconstruction of modern high energy physics experiments is a very complex task that puts stringent requirements onto the software realisation. The ATLAS track reconstruction software has been in the past dominated by a collection of individual packages, each of which incorporating a different intrinsic event data model, different data flow sequences and calibration data. Recently, the ATLAS track reconstruction has undergone a major design revolution to ensure maintainability during the long lifetime of the ATLAS experiment and the flexibility needed for the startup phase. The entire software chain has been re-organised in modular components and a common event data model has been deployed. A complete new track reconstruction that concentrates on common tools aimed to be used by both ATLAS tracking devices, the Inner Detector and the Muon System, has been established. It has been already used during many large scale tests with data from Monte Carlo simulation and from detector commissioning projects such as the combined test beam 2004 and cosmic ray events. This document concentrates on the technical and conceptual details of the newly developed track reconstruction.

  19. Ecological Character Displacement between the Sexes.

    PubMed

    De Lisle, Stephen P; Rowe, Locke

    2015-12-01

    Theory suggests that the evolution of sexual dimorphism in ecologically relevant traits can evolve purely through competition between the sexes for a shared resource. Although more parsimonious hypotheses exist for the evolution of ecological sexual dimorphisms, there are some underappreciated reasons to expect that competition may often play some role in the evolution of sexual dimorphism. Here, we build on past work to outline a set of sufficient criteria to demonstrate a role for resource competition in the evolution of sexual dimorphism, the most critical of which is that resource competition can be directly linked to sexual divergence along the axis of ecologically relevant dimorphism. We then compare the geometry of fitness surfaces across experimental manipulations of density and sex ratio in a semiaquatic salamander (Notophthalmus viridescens). We find consistent disruptive selection on multivariate sexual dimorphism in feeding morphology, which increases in strength with density. Fitness and the strength of divergent selection are negative-frequency dependent in the manner expected under competition-driven divergence between the sexes. Our results constitute direct evidence of resource competition as a driver of sexually antagonist selection and consequently the evolution of sexual dimorphism, providing an illustration of how cause and effect can be separated in studies of sexual divergence in morphology and ecology. We suggest that resource competition may often contribute to sexual divergence jointly with other sources of sex-biased selection, especially when ecological opportunity is sex specific. PMID:26655977

  20. Re-regeneration of lower jaws and the dental lamina in adult urodeles.

    PubMed

    Graver, H T

    1978-09-01

    Transverse amputations were carried out through one-third fully regenerated jaw segments and through normal tissue of the mandible on the same and opposite sides of the jaw in adults of Notophthalmus viridescens. Collectively the results suggest that, in adult urodeles, the mandible and the dental lamina can be replaced in an identical manner more than one time. Although the major histological events are the same in jaw regeneration and re-regeneration, regrowth is more rapid in re-regeneration. It appears that recently differentiated tissues of the regenerate have a higher capacity for regeneration than normal tissues amputated for the first time. Re-regeneration of the jaw occurs by growth of the original regenerate cartilage which has undergone reorganization. In re-regeneration, the skeletal elements exhibit no polarity and regrowth occurs in both directions, while the dental lamina possesses an anterior-posterior polarity and can regrow in an anterior direction only. Information concerning the mechanisms involved in the regenerative events remain to be determined.

  1. Batesian mimics influence the evolution of conspicuousness in an aposematic salamander.

    PubMed

    Kraemer, A C; Serb, J M; Adams, D C

    2015-05-01

    Conspicuousness, or having high contrast relative to the surrounding background, is a common feature of unpalatable species. Several hypotheses have been proposed to explain the occurrence of conspicuousness, and while most involve the role of conspicuousness as a direct signal of unpalatability to potential predators, one hypothesis suggests that exaggerated conspicuousness may evolve in unpalatable species to reduce predator confusion with palatable species (potential Batesian mimics). This hypothesis of antagonistic coevolution between palatable and unpalatable species hinges on the 'cost of conspicuousness', in which conspicuousness increases the likelihood of predation more in palatable species than in unpalatable species. Under this mimicry scenario, four patterns are expected: (i) mimics will more closely resemble local models than models from other localities, (ii) there will be a positive relationship between mimic and model conspicuousness, (iii) models will be more conspicuous in the presence of mimics, and (iv) when models and mimics differ in conspicuousness, mimics will be less conspicuous than models. We tested these predictions in the salamander mimicry system involving Notophthalmus viridescens (model) and one colour morph of Plethodon cinereus (mimic). All predictions were supported, indicating that selection for Batesian mimicry not only influences the evolution of mimics, but also the evolution of the models they resemble. These findings indicate that mimicry plays a large role in the evolution of model warning signals, particularly influencing the evolution of conspicuousness.

  2. Parasitism in a community context: trait-mediated interactions with competition and predation.

    PubMed

    Raffel, Thomas R; Hoverman, Jason T; Halstead, Neal T; Michel, Patrick J; Rohr, Jason R

    2010-07-01

    Predation and competition can induce important density- and trait-mediated effects on species, with implications for community stability. However, interactions of these factors with parasitism remain understudied. Here we investigate interactions among competition, predation and parasitism by crossing tadpole density (Bufo americanus), presence of a caged predator (Notophthalmus viridescens), and Echinostoma trivolvis trematodes, experimentally partitioning their effects on tadpole exposure and susceptibility to infection. Predation did not affect E. trivolvis infection but accelerated tadpole development and growth, and decreased activity. The presence of E. trivolvis caused the opposite effects on these three responses and reduced tadpole survival. High conspecific density reduced tadpole survival, growth, and development, and increased tadpole activity. Effects of predation and parasitism on activity were only evident at low tadpole density. High-density mesocosms also had twice the number of E. trivolvis infections as low-density mesocosms, despite a lack of evidence for stress-induced immunomodulation. Instead, this effect was explained by high density delaying tadpole development, which increased both the duration of exposure to cercariae and susceptibility to infection, because tadpoles spent more time in highly susceptible early stages. These results highlight the importance of accounting for trait-mediated effects, host plasticity, and exposure vs. susceptibility in parasite ecology.

  3. Batrachochytrium dendrobatidis infection dynamics vary seasonally in upstate New York, USA.

    PubMed

    Lenker, Melissa A; Savage, Anna E; Becker, C Guilherme; Rodriguez, David; Zamudio, Kelly R

    2014-08-21

    The amphibian disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a major cause of worldwide amphibian declines and extinctions. Although several studies indicate that Bd prevalence and infection intensity vary seasonally, temporal variation of Bd at high-latitude sites, such as the northeastern USA, is still poorly characterized. We screened amphibians for Bd monthly at 2 study sites in New York State from April to October 2011 and used quantitative polymerase chain reaction (qPCR) to detect and quantify temporal variability in Bd infection prevalence and intensity. We found pronounced seasonal variation in both Bd infection prevalence and intensity at the community level, and our data indicate that this pattern is due to a few species (Lithobates catesbeianus, L. clamitans, and Notophthalmus viridescens) that drive temporal variability in disease dynamics. Amphibian body mass and sex were significant predictors of infection intensity but not infection prevalence. Understanding the temporal dynamics of Bd host-pathogen interactions provides important insight into regional, seasonal, and host-specific determinants of disease outbreaks. Further, our study elucidates the most relevant and informative timing for Bd surveys in temperate amphibian assemblages. Seasonal variation of infection dynamics suggests that Bd surveys from different sampling time points are not comparable, and summer surveys to evaluate chytridiomycosis may significantly underestimate Bd prevalence and intensity, leading to false conclusions about the severity of chytridiomycosis-induced amphibian mortality and population decline.

  4. Solving chemical equilibrium problems using nonlinear optimization. [NEWT

    SciTech Connect

    Parkinson, W.J.; Sanderson, J.G.

    1984-06-01

    This report describes a program that will solve general chemical equilibrium problems of the type found in synthetic fossil-fuel plants. The program described here will also solve chemical equilibrium problems that are associated with unit operations that are found in refineries and ammonia plants. The most common problem encountered involves finding the equilibrium composition of a mixture, given feed composition, and the desired equilibrium temperature and pressure. Another less common problem requires the computation of the equilibrium temperature as well as the equilibrium composition for an adiabatic or other nonisothermal reaction. A constrained multidimensional Newton's method is used to solve the common isothermal equilibrium problem. The nonisothermal problem is solved by nesting the same multidimensional Newton's method inside a one-dimensional Newton's method that iterates on temperature. The program allows a gas phase with up to 20 reacting gases and the possibility of one solid phase (graphitic carbon).

  5. Evolutionary ecology of facultative paedomorphosis in newts and salamanders.

    PubMed

    Denoël, Mathieu; Joly, Pierre; Whiteman, Howard H

    2005-11-01

    Facultative paedomorphosis is an environmentally induced polymorphism that results in the coexistence of mature, gilled, and fully aquatic paedomorphic adults and transformed, terrestrial, metamorphic adults in the same population. This polymorphism has been of interest to scientists for decades because it occurs in a large number of caudate amphibian taxa as well as in a large diversity of habitats. Numerous experimental and observational studies have been conducted to explain the proximate and ultimate factors affecting these heterochronic variants in natural populations. The production of each alternative phenotype is based on a genotypexenvironment interaction and research suggests that differences in the environment can produce paedomorphs through several ontogenetic pathways. No single advantage accounts for the maintenance of this polymorphism. Rather, the interplay of different costs and benefits explains the success of the polyphenism across variable environments. Facultative paedomorphosis allows individuals to cope with habitat variation, to take advantage of environmental heterogeneity in the presence of open niches, and to increase their fitness. This process is expected to constitute a first step towards speciation events, and is also an example of biodiversity at the intraspecific level. The facultative paedomorphosis system is thus ripe for future studies encompassing ecology, evolution, behaviour, endocrinology, physiology, and conservation biology. Few other systems have been broad enough to provide varied research opportunities on topics as diverse as phenotypic plasticity, speciation, mating behaviour, and hormonal regulation of morphology. Further research on facultative paedomorphosis will provide needed insight into these and other important questions facing biologists.

  6. Widespread occurrence of the amphibian chytrid fungus Batrachochytrium dendrobatidis in the southeastern USA

    USGS Publications Warehouse

    Rothermel, B.B.; Walls, S.C.; Mitchell, J.C.; Dodd, C.K.; Irwin, L.K.; Green, D.E.; Vazquez, Victoria M.; Petranka, James W.; Stevenson, Dirk J.

    2008-01-01

    From 1999 to 2006, we sampled >1200 amphibians for the fungal pathogen Batrachochytnum dendrobatidis (Bd) at 30 sites in the southeastern USA. Using histological techniques or PCR assays, we detected chytrid infection in 10 species of aquatic-breeding amphibians in 6 states. The prevalence of chytrid infection was 17.8% for samples of postmetamorphic amphibians examined using skin swab-PCR assays (n = 202 samples from 12 species at 4 sites). In this subset of samples, anurans had a much higher prevalence of infection than caudates (39.2% vs. 5.5%, respectively). Mean prevalence in ranid frogs was 40.7 %. The only infected salamanders were Notophthalmus viridescens at 3 sites. We found infected amphibians from late winter through late spring and in 1 autumn sample. Although we encountered moribund or dead amphibians at 9 sites, most mortality events were not attributed to Bd. Chytridiomycosis was established as the probable cause of illness or death in fewer than 10 individuals. Our observations suggest a pattern of widespread and subclinical infections. However, because most of the sites in our study were visited only once, we cannot dismiss the possibility that chytridiomycosis is adversely affecting some populations. Furthermore, although there is no evidence of chytrid-associated declines in our region, the presence of this pathogen is cause for concern given global climate change and other stressors. Although presence-absence surveys may still be needed for some taxa, such as bufonids, we recommend that future researchers focus on potential population-level effects at sites where Bd is now known to occur. ?? Inter-Research 2008.

  7. Widespread occurrence of the amphibian chytrid fungus Batrachochytrium dendrobatidis in the southeastern USA

    USGS Publications Warehouse

    Rothermel, Betsie B.; Walls, Susan C.; Mitchell, Joseph C.; Dodd, C. Kenneth; Irwin, Lisa K.; Green, David E.; Vazquez, Victoria M.; Petranka, James W.; Stevenson, Dirk J.

    2008-01-01

     From 1999 to 2006, we sampled >1200 amphibians for the fungal pathogen Batrachochytrium dendrobatidis(Bd) at 30 sites in the southeastern USA. Using histological techniques or PCR assays, we detected chytrid infection in 10 species of aquatic-breeding amphibians in 6 states. The prevalence of chytrid infection was 17.8% for samples of postmetamorphic amphibians examined using skin swab-PCR assays (n = 202 samples from 12 species at 4 sites). In this subset of samples, anurans had a much higher prevalence of infection than caudates (39.2% vs. 5.5%, respectively). Mean prevalence in ranid frogs was 40.7%. The only infected salamanders were Notophthalmus viridescens at 3 sites. We found infected amphibians from late winter through late spring and in 1 autumn sample. Although we encountered moribund or dead amphibians at 9 sites, most mortality events were not attributed to Bd. Chytridiomycosis was established as the probable cause of illness or death in fewer than 10 individuals. Our observations suggest a pattern of widespread and subclinical infections. However, because most of the sites in our study were visited only once, we cannot dismiss the possibility that chytridiomycosis is adversely affecting some populations. Furthermore, although there is no evidence of chytrid-associated declines in our region, the presence of this pathogen is cause for concern given global climate change and other stressors. Although presence-absence surveys may still be needed for some taxa, such as bufonids, we recommend that future researchers focus on potential population-level effects at sites where Bd is now known to occur.

  8. Herpetofaunal Community Change in Multiple Habitats after Fifteen Years in a Southwest Florida Preserve, USA

    PubMed Central

    Cassani, John R.; Croshaw, Dean A.; Bozzo, Joseph; Brooks, Brenda; Everham, Edwin M.; Ceilley, David W.; Hanson, Deborah

    2015-01-01

    Herpetofaunal declines have been documented globally, and southern Florida, USA, is an especially vulnerable region because of high impacts from hydrological perturbations and nonindigenous species. To assess the extent of recent change in herpetofauna community composition, we established a baseline inventory during 1995-97 at a managed preserve in a habitat rich area of southwest Florida, and repeated our sampling methods fifteen years later (2010-11). Nine drift fence arrays were placed in four habitat types: mesic flatwood, mesic hammock, depression marsh, and wet prairie. Trapping occurred daily for one week during 7-8 sampling runs in each period (57 and 49 total sampling days, respectively). Species richness was maintained in mesic hammock habitats but varied in the others. Catch rates of several native species (Anaxyrus terrestris, Lithobates grylio, Anolis carolinensis, Nerodia fasciata) declined significantly. Other native species (Lithobates sphenocephalus, Siren lacertian, and Notophthalmus viridescens piaropicola) that were abundant in 1995-97 declined by greater than 50%. Catch rate of only two species (the nonindigenous Anolis sagrei and the native Diadophis punctatus) increased significantly. Hierarchical cluster analysis indicated similarity within habitat types but significant dissimilarity between sampling periods, confirming shifts in community composition. Analysis of individual species’ contributions to overall similarity across habitats shows a shift from dominance of native species in the 1990s to increased importance of nonindigenous species in 2010-11. Although natural population fluctuations may have influenced differences between the two sampling periods, our results suggest considerable recent change in the structure and composition of this southwest Florida herpetofaunal community. The causes are unknown, but hydrological shifts and ecological impacts of nonindigenous species may have contributed. PMID:26016475

  9. Pigment patterns of larval salamanders (Ambystomatidae, Salamandridae): the role of the lateral line sensory system and the evolution of pattern-forming mechanisms.

    PubMed

    Parichy, D M

    1996-05-01

    In many species of salamanders, pigment cells derived from the neural crest give rise to a horizontal stripe pattern in hatchling larvae. A defining element of these horizontal stripe patterns is a region over the middle of the myotomes that is relatively free of melanophores. This study shows that formation of a "melanophore-free region" and horizontal stripe pattern in Ambystoma tigrinum tigrinum (family Ambystomatidae) correlates with the development of the trunk lateral line sensory system. Moreover, prevention of lateral line development results in greater densities of melanophores in the middle of the flank, essentially eliminating the melanophore-free region in this taxon. A phylogenetic survey also revealed that ablation of the lateral lines has qualitatively similar effects on melanophores in seven of eight additional taxa (Ambystomatidae: A. barbouri, A. maculatum, A. talpoideum; Salamandridae: Notophthalmus viridescens, Pleurodeles waltl, Taricha granulosa, T. rivularis). In Taricha torosa, however, a superficially similar melanophore-free region forms prior to lateral line development, and ablation of the lateral lines does not perturb the horizontal stripe pattern. Finally, heterospecific grafting experiments demonstrated that T. torosa lateral lines are competent to generate a melanophore-free region, and T. torosa melanophores are competent to respond to cues associated with the lateral lines. These results indicate that lateral line-dependent pattern-forming mechanisms are common and probably ancestral within the families Ambystomatidae and Salamandridae and suggest that these ancestral mechanisms have been retained in T. torosa as redundant, lateral line-dependent mechanisms for stripe formation have evolved. PMID:8626032

  10. The mesencephalic locomotor region sends a bilateral glutamatergic drive to hindbrain reticulospinal neurons in a tetrapod

    PubMed Central

    Ryczko, Dimitri; Auclair, Francois; Cabelguen, Jean‐Marie

    2015-01-01

    In vertebrates, stimulation of the mesencephalic locomotor region (MLR) on one side evokes symmetrical locomotor movements on both sides. How this occurs was previously examined in detail in a swimmer using body undulations (lamprey), but in tetrapods the downstream projections from the MLR to brainstem neurons are not fully understood. Here we examined the brainstem circuits from the MLR to identified reticulospinal neurons in the salamander Notophthalmus viridescens. Using neural tracing, we show that the MLR sends bilateral projections to the middle reticular nucleus (mRN, rostral hindbrain) and the inferior reticular nucleus (iRN, caudal hindbrain). Ca2+ imaging coupled to electrophysiology in in vitro isolated brains revealed very similar responses in reticulospinal neurons on both sides to a unilateral MLR stimulation. As the strength of MLR stimulation was increased, the responses increased in size in reticulospinal neurons of the mRN and iRN, but the responses in the iRN were smaller. Bath‐application or local microinjections of glutamatergic antagonists markedly reduced reticulospinal neuron responses, indicating that the MLR sends glutamatergic inputs to reticulospinal neurons. In addition, reticulospinal cells responded to glutamate microinjections and the size of the responses paralleled the amount of glutamate microinjected. Immunofluorescence coupled with anatomical tracing confirmed the presence of glutamatergic projections from the MLR to reticulospinal neurons. Overall, we show that the brainstem circuits activated by the MLR in the salamander are organized similarly to those previously described in lampreys, indicating that the anatomo‐physiological features of the locomotor drive are well conserved in vertebrates. J. Comp. Neurol. 524:1361–1383, 2016. © 2015 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:26470600

  11. Movement patterns and the conservation of amphibians breeding in small, temporary wetlands

    USGS Publications Warehouse

    Dodd, C.K.; Cade, B.S.

    1998-01-01

    Many amphibians breed in water but live most of their lives in terrestrial habitats. Little is known, however, about the spatial distribution of these habitats or of the distances and directions amphibians move to reach breeding sites. The amphibian community at a small, temporary pond in northcentral Florida was monitored for 5 years. Based on captures and recaptures of more than 2500 striped newts (Notophthalmus perstriatus) and 5700 eastern narrow-mouthed toads (Gastrophryne carolinensis), we tabulated the angles of orientation that these amphibians entered and exited the pond basin. Our results showed that movements of these species between the pond and terrestrial habitats were nonrandom in orientation, but that narrow corridors did not appear to be used. Differences between the species likely reflect differences in habitat preferences, whereas intraspecific differences among years and between the sexes likely reflect variation among individuals. For terrestrial buffer zones to be effective at conserving pond-breeding amphibian communities, they need both a distance and a directional component. The determination of a directional component may be obscured if studies are carried out over a short time span. Conservation efforts for wetland-breeding amphibians that concentrate solely on the wetland likely will fail without consideration of the adjacent terrestrial habitat.

  12. Use of stable isotopes to differentiate between multiple groundwater contaminant sources

    SciTech Connect

    Kim, P.Y.; Bovitz, P.; VanDerveer, B.; Donohue, M.; Sprenger, M.; Munney, K.

    1994-12-31

    A wildlife kill in a northeastern freshwater pond, downgradient of a municipal landfill, was investigated. Chemical analyses of water, sediment, minnow (Pimephales sp.), and newt (Notophthalmus sp.) tissue was conducted in conjunction with histopathological analyses, toxicity evaluations, and a site reconnaissance. Elevated levels of volatile organic compounds (VOCs), Aroclor 1248, cyanide, and metals in water, sediment, and tissue suggested that contaminants were released into the pond from an upgradient source. In addition, the presence of a floating oil on the pond surface (originating from an upgradient source) exceeded the US EPA Ambient Water Quality Criterion for oil and grease. Bacterial, parasitological, and histopathological tests conducted on minnow tissue did not implicate any pathogenic organism to be associated with mortality. Results of the toxicity evaluation of seep water from the upgradient source revealed a significant (p < 0.05) reduction in survival and growth of fathead minnows (Pimephales promelas) from the control. Water quality parameters measured at the time of the field investigation revealed normal conditions.

  13. Tadpoles balance foraging and predator avoidance: Effects of predation, pond drying, and hunger

    USGS Publications Warehouse

    Bridges, C.M.

    2002-01-01

    Organisms are predicted to make trade-offs when foraging and predator avoidance behaviors present conflicting demands. Balancing conflicting demands is important to larval amphibians because adult fitness can be strongly influenced by size at metamorphosis and duration of the larval period. Larvae in temporary ponds must maximize growth within a short time period to achieve metamorphosis before ponds dry, while simultaneously avoiding predators. To determine whether tadpoles trade off between conflicting demands, I examined tadpole (Pseudacris triseriata) activity and microhabitat use in the presence of red-spotted newts (Notopthalmus viridescens) under varying conditions of pond drying and hunger. Tadpoles significantly decreased activity and increased refuge use when predators were present. The proportion of active time tadpoles spent feeding was significantly greater in predator treatments, suggesting tadpoles adaptively balance the conflicting demands of foraging and predator avoidance without making apparent trade-offs. Tadpoles responded to simulated drying conditions by accelerating development. Pond drying did not modify microhabitat use or activity in the presence of predators, suggesting tadpoles perceived predation and hunger as greater immediate threats than desiccation, and did not take more risks.

  14. Description of a new species of crested newt, previously subsumed in Triturus ivanbureschi (Amphibia: Caudata: Salamandridae).

    PubMed

    Wielstra, B; Arntzen, J W

    2016-01-01

    Multilocus molecular data play a pivotal role in diagnosing cryptic species (i.e. genetically distinct but morphologically similar species). A multilocus phylogeographic survey has provided compelling evidence that Triturus ivanbureschi sensu lato comprises two distinct gene pools with restricted gene flow. We conclude that this taxon had better be treated as two distinct (albeit morphologically cryptic) species. The name T. ivanbureschi should be restricted to the western species, which is distributed in western Asiatic Turkey plus the south-eastern Balkan Peninsula. No name is as yet available for the eastern species, which is distributed in northern Asiatic Turkey. We propose the name T. anatolicus sp. nov. for the eastern species and provide a formal species description. PMID:27394852

  15. The complete mitochondrial genome sequence of Red knobby newt Tylototriton shanjing (Amphibia: Caudata).

    PubMed

    Jiang, Ye; Yang, Mingxian; Han, Fuyao; Li, Yan; Ni, Qingyong; Yao, Yongfang; Xu, Huailiang; Li, Ying; Zhang, Mingwang

    2016-07-01

    The complete mitogenome of Tylototriton shanjing is 16,661 bp in length with GenBank accession number KR154461, which contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), 2 ribosomal RNA genes (rRNA), and 1 control region (CR). The overall base composition of this mitogenome is biased toward AT content at 59.45%. Most of the PCGs and tRNA genes are located on the H-strand, except for ND6 subunit gene and eight tRNA genes, which were distributed on the L-strand. The PCGs used "ATG" and "GTG" as the start codons, while "TAA", "TAG", "AGA", and "T-" are used as stop codons. Almost all tRNA genes were folded into typical cloverleaf secondary structures. The T. shanjing genome had two tandem repeat sequences in the cob-noncoding region. The mitogenomic phylogenetic analyses shows that the genera Echinotriton and Tylototriton were clustered into a strong supported monophyletic clade, which is a sister clade to the genus Pleurodeles, this confirms the previous phylogenetic results. PMID:26065853

  16. Gamma ray astronomy beyond 2001: What instruments for the newt challenges?

    NASA Astrophysics Data System (ADS)

    Vedrenne, G.

    2001-03-01

    In spite of the recent successes of SIGMA, RXTE and Compton GRO, and the launch of INTEGRAL in 2001, a lot of questions will stay opened for the next decades in gamma-ray astronomy. In this context we have to think about future instrument concepts which will allow a new step in the understanding of high-energy phenomena at work in many exciting objects: binary systems with compact objects, active galactic nuclei, supernovae and novae, gamma ray bursters... A short overview of these new types of instruments will be given.

  17. What do Hillary Rodham Clinton and Newt Gingrich have in common?

    PubMed

    Drake, D F

    1995-10-25

    In a somewhat tongue-in-cheek style, this article tries to persuade conservatives that it might be in their best interests to consider broader health system reform alternatives in their quest to reduce the cost of federal health entitlements for a balanced budget by 2002. The conventional means for reducing the federal budget by $450 billion in 7 years will inflict much pain on many voters. The substitution of a new, more targeted entitlement, prospectively, for all Americans represents an alternative that provides much gain to many and only some pain to a few.

  18. The complete mitochondrial genome sequence of Wenxian Knobby Newt Tylototriton wenxianensis (Amphibia: Caudata).

    PubMed

    Han, Fuyao; Jiang, Ye; Zhang, Mingwang

    2016-07-01

    We newly sequenced the mitochondrial genome of Tylototriton wenxianensis. The total length of the T. wenxianensis mitogenome is 16 265 bp, with GenBank accession number KR733683. It consists of 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNA), 22 transfer RNA genes (tRNA), and one control region (CR). Most of the genes are encoded on the H-strand, except for eight tRNA and ND6, which are encoded on the L-strand. Our mitogenomic phylogenetic tree showed that the relationships among the genera Tylototriton, Echinotriton, and Pleurodeles were well supported, and which is consistent with the previous molecular phylogeny. PMID:26114322

  19. What do Hillary Rodham Clinton and Newt Gingrich have in common?

    PubMed

    Drake, D F

    1995-10-25

    In a somewhat tongue-in-cheek style, this article tries to persuade conservatives that it might be in their best interests to consider broader health system reform alternatives in their quest to reduce the cost of federal health entitlements for a balanced budget by 2002. The conventional means for reducing the federal budget by $450 billion in 7 years will inflict much pain on many voters. The substitution of a new, more targeted entitlement, prospectively, for all Americans represents an alternative that provides much gain to many and only some pain to a few. PMID:7563541

  20. Description of a new species of crested newt, previously subsumed in Triturus ivanbureschi (Amphibia: Caudata: Salamandridae).

    PubMed

    Wielstra, B; Arntzen, J W

    2016-05-05

    Multilocus molecular data play a pivotal role in diagnosing cryptic species (i.e. genetically distinct but morphologically similar species). A multilocus phylogeographic survey has provided compelling evidence that Triturus ivanbureschi sensu lato comprises two distinct gene pools with restricted gene flow. We conclude that this taxon had better be treated as two distinct (albeit morphologically cryptic) species. The name T. ivanbureschi should be restricted to the western species, which is distributed in western Asiatic Turkey plus the south-eastern Balkan Peninsula. No name is as yet available for the eastern species, which is distributed in northern Asiatic Turkey. We propose the name T. anatolicus sp. nov. for the eastern species and provide a formal species description.

  1. Detection of mutagenicity in drinking water using a micronucleus test in newt larvae (Pleurodeles waltl).

    PubMed

    Jaylet, A; Gauthier, L; Fernandez, M

    1987-05-01

    We have previously described a micronucleus test using erythrocytes from larvae of the urodele amphibians Pleurodeles waltl (pleurodele) and Ambystoma mexicanum (axolotl). The test is based on a comparison of the levels of micronucleated erythrocytes in blood smears from larvae reared in water containing a clastogen, with the levels from larvae reared in purified water. Using larvae from the pleurodele, we have employed this test to evaluate mutagenic activity in drinking water. Groups of larvae were reared in tap water, while control groups were reared in tap water which had been filtered over sand and active carbon to remove micropollutants. Seven separate tests carried out between October 1985 and May 1986 all gave positive results of varying degree depending on the time of year. This test is therefore able to detect clastogens in normal drinking water. It could be used for quality control of drinking water during the various stages in the treatment of raw water without any requirement for prior extraction or concentration of micropollutants.

  2. Pond Identification, Classification, and Inundation Dynamics at St. Marks National Wildlife Refuge in northwest Florida, USA

    NASA Astrophysics Data System (ADS)

    Riley, J. W.; Calhoun, D.; Barichivich, J.

    2012-12-01

    The persistence and resilience of amphibian communities is largely dependent on adequate breeding habitat. This is especially important for threatened and endangered species that may often exist as isolated populations and have specific requirements for breeding. A study currently being conducted by the U.S. Geological Survey is investigating the feasibility of a repatriation effort of the Striped Newt (Notophthalmus perstriatus), a federal candidate species, within the St. Marks National Wildlife Refuge (SMNWR) in northwest Florida. This amphibian species requires ponds that are free of fishes and, for this reason, generally chooses ephemeral ponds as breeding sites. The delineation of potential breeding habitat is a first step in selecting candidate areas for repatriation. To achieve this, a LIDAR (Light Detection and Ranging) derived digital elevation model (DEM) and a topographic position index (TPI) classification scheme was used to identify and classify isolated depressions across the landscape. The TPI evaluates the difference in elevation from a central DEM cell to the mean elevation of a neighborhood of surrounding DEM cells and is a robust tool for locating depressional features within a landscape. These candidate depression features were then screened to remove large perennial ponds and smaller connected ponds from further consideration. In addition, the perimeters of twenty-two field identified ephemeral ponds were surveyed with a high precision RTK GPS (Real Time Kinematic Global Positioning System) unit to provide a calibration dataset to evaluate the performance of the feature identification method. This set of ponds was also instrumented with water-level recorders to investigate inundation dynamics across a wide range of hydrologic conditions. We anticipate being able to classify pond hydroperiod—thus each pond's potential as breeding habitat—at the monitored locations through this combination of approaches. Using estimates of pond size

  3. Assessment of environmental DNA for detecting presence of imperiled aquatic amphibian species in isolated wetlands

    USGS Publications Warehouse

    Mckee, Anna; Calhoun, Daniel L.; Barichivich, William J.; Spear, Stephen F.; Goldberg, Caren S.; Glenn, Travis C

    2015-01-01

    Environmental DNA (eDNA) is an emerging tool that allows low-impact sampling for aquatic species by isolating DNA from water samples and screening for DNA sequences specific to species of interest. However, researchers have not tested this method in naturally acidic wetlands that provide breeding habitat for a number of imperiled species, including the frosted salamander (Ambystoma cingulatum), reticulated flatwoods salamanders (Ambystoma bishopi), striped newt (Notophthalmus perstriatus), and gopher frog (Lithobates capito). Our objectives for this study were to develop and optimize eDNA survey protocols and assays to complement and enhance capture-based survey methods for these amphibian species. We collected three or more water samples, dipnetted or trapped larval and adult amphibians, and conducted visual encounter surveys for egg masses for target species at 40 sites on 12 different longleaf pine (Pinus palustris) tracts. We used quantitative PCRs to screen eDNA from each site for target species presence. We detected flatwoods salamanders at three sites with eDNA but did not detect them during physical surveys. Based on the sample location we assumed these eDNA detections to indicate the presence of frosted flatwoods salamanders. We did not detect reticulated flatwoods salamanders. We detected striped newts with physical and eDNA surveys at two wetlands. We detected gopher frogs at 12 sites total, three with eDNA alone, two with physical surveys alone, and seven with physical and eDNA surveys. We detected our target species with eDNA at 9 of 11 sites where they were present as indicated from traditional surveys and at six sites where they were not detected with traditional surveys. It was, however, critical to use at least three water samples per site for eDNA. Our results demonstrate eDNA surveys can be a useful complement to traditional survey methods for detecting imperiled pond-breeding amphibians. Environmental DNA may be particularly useful in situations

  4. Effect of Pleistocene climatic oscillations on the phylogeography and demography of red knobby newt (Tylototriton shanjing) from southwestern China.

    PubMed

    Yu, Guohua; Zhang, Mingwang; Rao, Dingqi; Yang, Junxing

    2013-01-01

    Factors that determine the genetic structure of species in southwestern China remain largely unknown. In this study, phylogeography and demography of Tylototriton shanjing was investigated from a mitochondrial perspective to address the role of the Quaternary ice ages in shaping phylogeographic history and genetic diversity of Yunnan. A total of 146 individuals from 19 populations across the entire range of the species were collected. We detected four maternal phylogenetic lineages corresponding to four population groups, and found that major glaciation events during the Pleistocene have triggered the intra-specific divergence. Coalescent simulations indicated that the populations retreated to different refugia located in southern Yunnan, northwestern Yunnan, the border region of western Yunnan with Myanmar, and middle-western Yunnan, respectively, during previous glacial periods in the Pleistocene, and these four refugia were not retained during the Last Glacial Maximum. Population expansions occurred during the last inter-glaciation, during which ice core and pollen data indicated that the temperature and precipitation gradually increased, and declines of population sizes started after the beginning of the Last Glacial Maximum when the climate became cooler and dryer. The paleo-drainage system had no contribution to the current genetic structure and the rivers were not dispersal barriers for this salamander.

  5. Selection of physiological and metabolic adaptations to food deprivation in the Pyrenean newt Calotriton asper during cave colonisation.

    PubMed

    Issartel, Julien; Voituron, Yann; Guillaume, Olivier; Clobert, Jean; Hervant, Frédéric

    2010-01-01

    Food restriction is one of the major and most common constraints that subterranean animals face in their biotope. Cave-dwelling organisms thus have to cope with fasting periods that can extend from a month to a year. However, adaptive fasting resistance previously found in subterranean fauna has only been highlighted by direct comparisons with phylogenetically distant epigean organisms, which could severely impact conclusions. Here we report physiological and metabolic responses to 42 days of fasting followed by 10 days of refeeding in two populations (one subterranean and one epigean) of Calotriton asper. In the fed state (control), the hypogean population exhibited a hypometabolism together with higher glycogen (+25% in liver and muscles) and triglyceride stores (+50% in muscles). During the fasting period, cave individuals exhibited a 20% decrease in VO(2) whereas epigean individuals experienced no significant change. In addition, the energetic reserves always remained higher in the hypogean population. According to phylogenic and biogeographic data, cave colonization by this species dates back to less than 10,000 years, suggesting a rapid selection of adaptive traits related to fasting. This study strongly suggests that cave colonization induces a decrease in metabolism together with a higher capacity to accumulate energy reserves and therefore to withstand unpredictable fasting periods.

  6. Increased slow transport in axons of regenerating newt limbs after a nerve conditioning lesion made prior to amputation

    SciTech Connect

    Maier, C.E.

    1989-01-01

    The first part of this study shows that axonal density is constant in the limb stump of the next proximal to the area of traumatic nerve degeneration caused by limb amputation. The results of the second part of this work reveal that a nerve conditioning lesion made two weeks prior to amputation is associated with accelerated limb regeneration and that this accelerated limb regeneration is accompanied by an earlier arrival of axons. This is the first demonstration of naturally occurring limb regeneration being enhanced. In this study SCb cytoskeletal proteins were identified and measured using SDS-PAGE and liquid scintillation counting. Proteins were measured at 7, 14, 21, and 28 days after {sup 35}S-methionine injection and the normal rate of SCb transport determined to be 0.19 mm/day. A single axotomy does not enhance the rate of SCb transport but does increase the amount of labeled SCb proteins that are transported. When a conditioning lesion is employed prior to limb amputation and SCb proteins are measured at 7, 14, and 21 days after injection, there is a twofold acceleration in the rate of SCb transport and an increase in the amount of SCb proteins transported in conditioned axons.

  7. 78 FR 26359 - FFP Project 111, LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-06

    ... Corps of Engineers' (Corps) Newt Graham Lock and Dam, located on the Verdigris River near the town of... annual generation of 32, 300 megawatt-hours, and utilize surplus water from the Newt Graham Lock and...

  8. STS-65 Mission Onboard Photograph

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Donald Thomas conducts the Fertilization and Embryonic Development of Japanese Newt in Space (AstroNewt) experiment at the Aquatic Animal Experiment Unit (AAEU) inside the International Microgravity Laboratory-2 (IML-2) science module. The AstroNewt experiment aims to know the effects of gravity on the early developmental process of fertilized eggs using a unique aquatic animal, the Japanese red-bellied newt. The newt egg is a large single cell at the begirning of development. The Japanese newt mates in spring and autumn. In late autumn, female newts enter hibernation with sperm in their body cavity and in spring lay eggs and fertilize them with the stored sperm. The experiment takes advantage of this feature of the newt. Groups of newts were sent to the Kennedy Space Center and kept in hibernation until the mission. The AAEU cassettes carried four newts aboard the Space Shuttle. Two newts in one cassette are treated by hormone injection on the ground to simulate egg laying. The other two newts are treated on orbit by the crew. The former group started maturization of eggs before launch. The effects of gravity on that early process were differentiated by comparison of the two groups. The IML-2 was the second in a series of Spacelab flights designed to conduct research by the international science community in a microgravity environment. Managed by the Marshall Space Flight Center, the IML-2 was launched on July 8, 1994 aboard the STS-65 Space Shuttle mission, Orbiter Columbia.

  9. STS-65 Mission Onboard Photograph

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Donald Thomas conducts the Fertilization and Embryonic Development of Japanese Newt in Space (AstroNewt) experiment at the Aquatic Animal Experiment Unit (AAEU) inside the International Microgravity Laboratory-2 (IML-2) science module. The AstroNewt experiment aims to know the effects of gravity on the early developmental process of fertilized eggs using a unique aquatic animal, the Japanese red-bellied newt. The newt egg is a large single cell at the begirning of development. The Japanese newt mates in spring and autumn. In late autumn, female newts enter hibernation with sperm in their body cavity and in spring lay eggs and fertilized them with the stored sperm. The experiment takes advantage of this feature of the newt. Groups of newts were sent to the Kennedy Space Center and kept in hibernation until the mission. The AAEU cassettes carried four newts aboard the Space Shuttle. Two newts in one cassette are treated by hormone injection on the ground to simulate egg laying. The other two newts are treated on orbit by the crew. The former group started maturization of eggs before launch. The effects of gravity on that early process were differentiated by comparison of the two groups. The IML-2 was the second in a series of Spacelab flights designed to conduct research by the international science community in a microgravity environment. Managed by the Marshall Space Flight Center, the IML-2 was launch on July 8, 1994 aboard the STS-65 Space Shuttle Orbiter Columbia mission.

  10. Sperm storage in females of the smooth newt (Triturus v. vulgaris L.): I. Ultrastructure of the spermathecae during the breeding season.

    PubMed

    Sever, D M; Halliday, T; Waights, V; Brown, J; Davies, H A; Moriarty, E C

    1999-01-01

    Sperm storage in cloacal spermathecae was studied in females of Triturus v. vulgaris collected early in the breeding season in southern England. Females collected in terrestrial situations, presumably unmated, were mated in the laboratory, and the ultrastructure of the transferred sperm and the spermathecae was observed at various intervals after mating. Sperm from a spermatophore cap lodged in a female's cloacal orifice can migrate into spermathecae within 1 hr after mating. Spherical structures on the axial fibers of some sperm in the cap could indicate immaturity. Disorderly clusters of sperm from the cap are still present in the cloacal chamber 12 hr after mating but are absent 24 hr after mating. During storage, sperm often are in tangled masses in the spermathecal tubules. The sperm are coated with spermathecal secretions, and some sperm nuclei were observed embedded in the spermathecal epithelium. Little evidence for spermiophagy early in the breeding season was found. During oviposition, mazes of sperm occur external to the spermathecal orifices, and sperm may be released in this condition onto eggs as they pass through the cloaca. The tangled clusters in which sperm are found from pick-up to oviposition are hypothesized as an adaptation to reduce the effectiveness of sperm competition from the ejaculates of rival males. Additional studies, using the same protocol and covering the entire cycle of sperm storage, are necessary to enable interspecific comparisons leading to phylogenetic hypotheses. PMID:9990737

  11. Fish predation on sea urchins on the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Young, M. A. L.; Bellwood, D. R.

    2012-09-01

    Predators are important for regulating adult sea urchin densities. Here, we employ remote underwater video cameras to record diurnal predation on tethered sea urchins at Lizard Island on the Great Barrier Reef (GBR). We identified four fish predators of adult sea urchins ( Balistoides viridescens, Balistapus undulatus, Lethrinus atkinsoni and Choerodon schoenleinii). Predator activity appeared to be site-specific. Balistoides viridescens and B. undulatus (f: Balistidae) were the two most important predators of Echinometra mathaei with the former handling E. mathaei significantly faster (mean 0.7 min) than B. undulatus (5.2 min). Balistoides viridescens also successfully preyed on 70 % of detections, while C. schoenleinii, B. undulatus and L. atkinsoni preyed on just 33, 17 and <1 %, respectively. Additionally, B. viridescens were behaviourally dominant among predator species and were observed as aggressors in 30 encounters with B. undulatus and 8 encounters with L. atkinsoni. In only one encounter was B. viridescens the recipient of any aggression (from B. undulatus). In terms of relative vulnerability, of the three sea urchin species examined, E. mathaei were more vulnerable to predation than Diadema setosum or Echinothrix calamaris, with mean handling times of 1.2, 4.8 and 10.3 min, respectively. Balistoides viridescens and B. undulatus both appear to be able to play an important role as predators of sea urchins on the relatively intact coral reefs of Lizard Island. However, B. viridescens emerge as the most efficient predator in terms of handling speed and the proportion of detections preyed upon. They were also the behaviourally dominant predator. This preliminary study of the predators of sea urchins on the GBR highlights the potential significance of relatively scarce but functionally important species.

  12. Effects of natural flooding and manual trapping on the facilitation of invasive crayfish-native amphibian coexistence in a semi-arid perennial stream

    USGS Publications Warehouse

    Kats, Lee B.; Bucciarelli, Gary; Vandergon, Thomas L.; Honeycutt, Rodney L.; Mattiasen, Evan; Sanders, Arthur; Riley, Seth P.D.; Kerby, Jacob L.; Fisher, Robert N.

    2013-01-01

    Aquatic amphibians are known to be vulnerable to a myriad of invasive predators. Invasive crayfish are thought to have eliminated native populations of amphibians in some streams in the semi-arid Santa Monica Mountains of southern California. Despite their toxic skin secretions that defend them from native predators, newts are vulnerable to crayfish attacks, and crayfish have been observed attacking adult newts, and eating newt egg masses and larvae. For 15 years, we have observed invasive crayfish and native California newts coexisting in one stream in the Santa Monica Mountains. During that period, we monitored the densities of both crayfish and newt egg mass densities and compared these to annual rainfall totals. After three seasons of below average rainfall, we reduced crayfish numbers by manual trapping. Our long-term data indicated that crayfish did not fare well in years when rainfall is above the historic average. This invasive predator did not evolve with high velocity streams, and observations indicated that southern California storm events washed crayfish downstream, killing many of them. Newts exhibit increased reproduction in years when crayfish numbers were reduced. A comparison with a nearby stream that does not contain crayfish indicated that newt reproduction positively responded to increased rainfall, but that fluctuations were much greater in the stream that contains crayfish. We suggest that rainfall patterns help explain invasive crayfish/newt coexistence and that management for future coexistence may benefit from manual trapping.

  13. Hypocrea rufa/Trichoderma viride: a reassessment, and description of five closely related species with and without warted conidia

    PubMed Central

    Jaklitsch, Walter M.; Samuels, Gary J.; Dodd, Sarah L.; Lu, Bing-Sheng; Druzhinina, Irina S.

    2006-01-01

    The type species of the genus Hypocrea (Hypocreaceae, Hypocreales, Ascomycota, Fungi), H. rufa, is re-defined and epitypified using a combination of phenotype (morphology of teleomorphs and anamorphs, and characteristics in culture) and phylogenetic analyses of the translation-elongation factor 1α gene. Its anamorph, T. viride, the type species of Trichoderma, is re-described and epitypified. Eidamia viridescens is combined as Trichoderma viridescens and is recognised as one of the most morphologically and phylogenetically similar relatives of T. viride. Its teleomorph is newly described as Hypocrea viridescens. Contrary to frequent citations of H. rufa and T. viride in the literature, this species is relatively rare. Although both T. viride and T. viridescens have a wide geographic distribution, their greatest genetic diversity appears to be in Europe and North America. Hypocrea vinosa is characterised and its anamorph, T. vinosum sp. nov., is described. Conidia of T. vinosum are subglobose and warted. The new species T. gamsii is proposed. It shares eidamia-like morphology of conidiophores with T. viridescens, but it has smooth, ellipsoidal conidia that have the longest L/W ratio that we have seen in Trichoderma. Trichoderma scalesiae, an endophyte of trunks of Scalesia pedunculata in the Galapagos Islands, is described as new. It only produces conidia on a low-nutrient agar to which filter paper has been added. Additional phylogenetically distinct clades are recognised and provisionally delimited from the species here described. Trichoderma neokoningii, a T. koningii-like species, is described from a collection made in Peru on a fruit of Theobroma cacao infected with Moniliophthora roreri. PMID:18490991

  14. Advancements in generalized-geometry discrete ordinates transport for lattice physics calculations

    SciTech Connect

    DeHart, M. D.

    2006-07-01

    This paper describes the generalized-geometry capabilities of the two-dimensional NEWT transport solver, used within the TRITON depletion sequence of the SCALE code system for lattice physics calculation. With the release of SCALE 5.1 in 2006, NEWT will introduce a new automated grid generation procedure based on simple body specifications, using an input format based on the SCALE Generalized-Geometry Processor. The paper will contrast the discretization techniques against those used in other unstructured grid treatments; illustrate the ease of model development, features, capabilities; and demonstrate the unique adaptability of NEWT for a wide range of fuel configurations. (authors)

  15. Going for the Gold.

    PubMed

    Serafini, M W

    1995-04-01

    J. Patrick Rooney, the chairman of Golden Rule Insurance Co., has an idea that he says will curb health care spending--and make money for his company. Newt Gingrich and other congressional Republicans appear sold on it.

  16. Spaceflight Effects on Hemopoiesis of Lower Vertebrates Flown on Foton-M2

    NASA Technical Reports Server (NTRS)

    Domaratskaya, E. I.; Payushina, O. V.; Butorina, M. N.; Nikonova, T. M.; Grigorian, E. N.; Mitashov, V. I.; Tairbekov, M. G.; Almeida, E.; Khrushchov, N. G.

    2006-01-01

    Intact and operated newts Pleumdeles waltl flown on Foton-M2 for 16 days were used to study the effects of spaceflight as well as tail amputation and lensectomy on their hemopoiesis. The flight did not produce noticeable changes in the peripheral blood of nonoperated newts. However, in operated animals, the number of lymphocytes increased whereas that of neutrophils decreased. There were no morphological differences in hemopoietic organs (liver and spleen) between flown non-operated and operated animals or their controls. However, in both non-operated and operated newts the liver weight and the number of hemopoietic cells in it increased. In contrast to nonoperated newts, space-flown mammals typically showed significant changes in blood cell counts. Experiments with BrdU incorporation revealed labeled cells in the hemopoietic area of the liver as well as in blood and spleen. This observation gives evidence that the BrdU label can be used to study proliferation of hemopoietic cells.

  17. Fingernails Yield Clues to Limb Regeneration

    MedlinePlus

    ... lead to the development of novel treatments for amputees. While salamanders and newts are well known for ... harness the process and develop new treatments for amputees." This research was supported by NIH’s National Institute ...

  18. Introduced goldfish affect amphibians through inhibition of sexual behaviour in risky habitats: an experimental approach.

    PubMed

    Winandy, Laurane; Denoël, Mathieu

    2013-01-01

    The introduction of alien species is one of the major causes of current and global biodiversity loss. The introduction of fish can be a particular threat to native amphibian populations, which are declining worldwide. One way for amphibians to persist in such altered environments is to adopt anti-predator strategies especially at the behavioural level. However, although it has been shown that avoidance behaviour may decrease the probability of being detected by a potential predator, little is known on the consequences on sexual behaviour. In this study, we tested the hypothesis that adult Alpine newts (Ichthyosaura alpestris) use shelters more often and exhibit less sexual activity in the presence of goldfish (Carassius auratus) and that they reduce sexual activity more in risky micro-habitats than in safe environments. To this end, we assessed behavioural patterns of adult newts in a replicated laboratory design. Goldfish were present in direct contact with newts in half of the tanks. Consistently throughout the study period, significantly more newts used shelter in the presence of fish than in their absence. Newts also significantly decreased their sexual activity level overall, but specially outside the shelter when they were in direct contact with fish. These results show that fish presence can affect newts in complex ways, such as through inhibition of their reproduction. Our work highlights that integrating behaviour in conservation studies is essential to understanding the patterns of coexistence and exclusion between introduced fish and amphibians.

  19. Brainstem neuronal and behavioral activation by corticotropin-releasing hormone depend on the behavioral state of the animal.

    PubMed

    Hubbard, Catherine S; Rose, James D

    2012-01-01

    Central administration of corticotropin-releasing hormone (CRH) is known to enhance locomotion across a wide range of vertebrates, including the roughskin newt, Taricha granulosa. The present study aimed to identify the CRH effects on locomotor-controlling medullary neurons that underlie the peptide's behavioral stimulating actions. Single neurons were recorded from the rostral medullary reticular formation before and after intraventricular infusion of CRH in freely behaving newts and newts paralyzed with a myoneural blocking agent. In behaving newts, most medullary neurons showed increased firing 3-23 min after CRH infusion. Decreases in firing were less common. Of particular importance was the finding that in behaving newts, medullary neurons showed a cyclic firing pattern that was strongly associated with an increase in the incidence of walking bouts, an effect blocked by pretreatment with the CRH antagonist, alpha-helical CRH and not seen following vehicle administration. In contrast, the majority of medullary neurons sampled in immobilized newts lacked temporal cyclicity in their firing patterns following intraventricular infusion of CRH. That is, there was no evidence for a fictive locomotor activity pattern. Our results indicate that the actual expression of locomotion is a critical factor in regulating the behavior-activating effects of CRH and underscore the importance of using an awake, unrestrained animal for analysis of a hormone's neurobehavioral actions.

  20. Nodal energy weighted transformation: A mistuning projection and its application to FLADE™ turbines

    NASA Astrophysics Data System (ADS)

    Fitzner, Colin; Epureanu, Bogdan I.; Filippi, Sergio

    2014-01-01

    In recent years, several researchers have developed reduced-order models (ROMs) to efficiently and accurately calculate the forced response of blisks with known small mistuning. Small mistuning consists of the small blade-to-blade structural differences which destroy the inherent cyclic symmetry of the structure. This paper presents a nodal energy weighted transformation (NEWT) which can be used to construct ROMs of mistuned blisks and dual flow path systems, such as FLADE™ turbines. The NEWT approach can be interpreted as a hybrid of two existing techniques: component mode mistuning (CMM) and the subset of nominal modes (SNM). Similar to the previous methods, NEWT assumes that the mistuned modes of the system are a linear combination of tuned modes. However, NEWT differs from its predecessors in the blisk substructuring and in the mistuning projection. Numerical results obtained using full order models, CMM, and NEWT are presented and compared over multiple frequency ranges for a finite element model of a blisk and that of a FLADE™ turbine. These results show that ROMs based on NEWT have several attractive features: (a) the accuracy of the ROMs is comparable to ROMs based on CMM, and can be improved by increasing the size of the projection mode subset; (b) no necessary modifications are needed to analyze FLADE™ turbines; and (c) the response of all modes can be predicted well even if they are not blade dominated.

  1. Introduced Goldfish Affect Amphibians through Inhibition of Sexual Behaviour in Risky Habitats: an Experimental Approach

    PubMed Central

    Winandy, Laurane; Denoël, Mathieu

    2013-01-01

    The introduction of alien species is one of the major causes of current and global biodiversity loss. The introduction of fish can be a particular threat to native amphibian populations, which are declining worldwide. One way for amphibians to persist in such altered environments is to adopt anti-predator strategies especially at the behavioural level. However, although it has been shown that avoidance behaviour may decrease the probability of being detected by a potential predator, little is known on the consequences on sexual behaviour. In this study, we tested the hypothesis that adult Alpine newts (Ichthyosaura alpestris) use shelters more often and exhibit less sexual activity in the presence of goldfish (Carassius auratus) and that they reduce sexual activity more in risky micro-habitats than in safe environments. To this end, we assessed behavioural patterns of adult newts in a replicated laboratory design. Goldfish were present in direct contact with newts in half of the tanks. Consistently throughout the study period, significantly more newts used shelter in the presence of fish than in their absence. Newts also significantly decreased their sexual activity level overall, but specially outside the shelter when they were in direct contact with fish. These results show that fish presence can affect newts in complex ways, such as through inhibition of their reproduction. Our work highlights that integrating behaviour in conservation studies is essential to understanding the patterns of coexistence and exclusion between introduced fish and amphibians. PMID:24312432

  2. Effect of high pressure on the microbiological quality of cooked chicken during storage at normal and abuse refrigeration temperatures.

    PubMed

    Patterson, Margaret F; McKay, Alan M; Connolly, Malachy; Linton, Mark

    2010-04-01

    Vacuum-packaged cooked poultry meat was treated at a range of pressures (400-600 MPa) and hold times (1, 2 and 10 min), followed by storage at 4 degrees , 8 degrees or 12 degrees C for up to 35 days. Weissella viridescens was found to be the dominant microorganism in the pressure-treated meat, constituting 100% of the microflora identified at 500 and 600 MPa. None of the pressure-treated samples had obvious signs of spoilage during the 35 day storage period, even when the Weissella count was >7 log(10) cfu/g. Studies on a typical W. viridescens isolate showed it to be relatively pressure-resistant in poultry meat, with <1 log reduction in numbers after a treatment of 2 min at 600 MPa. Agar diffusion assays showed that the isolate also caused the inhibition of a number of Gram-positive and Gram-negative pathogens, including strains of Clostridium botulinum, Listeria monocytogenes, Bacillus cereus and Escherichia coli. The selection of a pressure-resistant organism, such as this Weissella sp. could be advantageous in extending the shelf-life, and also microbiological safety, of the cooked meat, as it could give protection in addition to the pressure treatment itself.

  3. Effect of high pressure, in combination with antilisterial agents, on the growth of Listeria monocytogenes during extended storage of cooked chicken.

    PubMed

    Patterson, M F; Mackle, A; Linton, M

    2011-12-01

    A cocktail of Listeria monocytogenes strains was inoculated into cooked chicken (∼2.2 × 10³ CFU g⁻¹) which was then pressure-treated (600 MPa/2 min/20 °C) and stored for up to 105 days at 8 °C. In addition, sodium lactate (2% w/w) or a pressure-resistant Weissella viridescens strain, known to have antilisterial activity, were added to the meat prior to inoculation with the pathogen and pressure treatment, to investigate the effect on Listeria survival. Pressure treatment alone was not sufficient to eliminate all of the Listeria. Numbers of survivors were initially below the level of detection (50 CFU g⁻¹) but increased during storage to reach >10⁸ CFU g⁻¹ by day 21. The presence of W. viridescens significantly extended the lag phase of any Listeria that survived the initial pressure treatment by ∼35 days, but numbers then increased to reach ∼10⁷ CFU g⁻¹ by day 105. The addition of 2% sodium lactate in combination with pressure treatment was most effective at inhibiting the growth of L. monocytogenes and numbers remained below the limit of detection throughout the 105 day storage. The addition of antimicrobial agents, in combination with pressure, could be used to give additional food safety assurance without increasing pressure hold time.

  4. Validation of standardized computer analyses for licensing evaluation/TRITON two-dimensional and three-dimensional models for light water reactor fuel

    SciTech Connect

    Bowman, S. M.; Gill, D. F.

    2006-07-01

    The isotopic depletion capabilities of the new Standardized Computer Analyses for Licensing Evaluation control module TRITON, coupled with ORIGEN-S, were evaluated using spent fuel assays from several commercial light water reactors with both standard and mixed-oxide fuel assemblies. Calculations were performed using the functional modules NEWT and KENO-VI. NEWT is a two-dimensional, arbitrary-geometry, discrete-ordinates transport code, and KENO-VI is a three-dimensional Monte Carlo transport code capable of handling complex three-dimensional geometries. To validate the codes and data used in depletion calculations, numerical predictions were compared with experimental measurements for a total of 29 samples taken from the Calvert Cliffs, Obrigheim, and San Onofre pressurized water reactors and the Gundremmingen boiling water reactor. Similar comparisons have previously been performed at the Oak Ridge National Laboratory for the one-dimensional SAS2H control module. The SAS2H, TRITON/KENO-VI, and TRITON/NEWT results were compared for corresponding samples. All analyses showed that TRITON/KENO-VI and TRITON/NEWT produced typically similar or better results than SAS2H. The calculations performed in this validation study demonstrate that the depletion capabilities of TRITON accurately model spent fuel depletion and decay. (authors)

  5. [Biologically Active Peptides of King Crab Hepatopancreas].

    PubMed

    Bogdanov, V V; Berezin, B B; Il'ina, A P; Yamskova, V P; Yamskov, I A

    2015-01-01

    Substances of a peptide nature isolated from the hepatopancreas of the king crab Paralithodes camtschaticus exhibited physicochemical properties and membranotropic and specific activities similar to those of membranotropic homeostatic tissue-specific bioregulators previously found in different mammalian and plant tissues. Their biological effect on vertebrate tissues was demonstrated on a model of roller organotypic cultivation of Pleurodeles waltl newt liver tissue. PMID:26353409

  6. All about Amphibians. Animal Life for Children. [Videotape].

    ERIC Educational Resources Information Center

    2000

    This videotape teaches children about their favorite amphibious creatures, as well as amphibians' nearest cousins--toads, newts, and salamanders. Young students discover how these amazing creatures can live both in and out of water, learn about the amphibious life cycle, and compare the differences between amphibians and reptiles. This videotape…

  7. Phase-II conjugation ability for PAH metabolism in amphibians: characteristics and inter-species differences.

    PubMed

    Ueda, Haruki; Ikenaka, Yoshinori; Nakayama, Shouta M M; Tanaka-Ueno, Tomoko; Ishizuka, Mayumi

    2011-10-01

    The present study examines amphibian metabolic activity - particularly conjugation - by analysis of pyrene (a four ring, polycyclic aromatic hydrocarbon) metabolites using high-performance liquid chromatography (HPLC) with fluorescence detector (FD), a mass spectrometry detector (MS) system and kinetic analysis of conjugation enzymes. Six amphibian species were exposed to pyrene (dissolved in water): African claw frog (Xenopus laevis); Tago's brown frog (Rana tagoi); Montane brown frog (Rana ornativentris); Wrinkled frog (Rana rugosa); Japanese newt (Cynops pyrrhogaster); and Clouded salamander (Hynobius nebulosus); plus one fish species, medaka (Oryzias latipes); and a fresh water snail (Clithon retropictus), and the resultant metabolites were collected. Identification of pyrene metabolites by HPLC and ion-trap MS system indicated that medaka mainly excreted pyrene-1-glucuronide (PYOG), while pyrene-1-sulfate (PYOS) was the main metabolite in all amphibian species. Pyrene metabolites in amphibians were different from those in invertebrate fresh water snails. Inter-species differences were also observed in pyrene metabolism among amphibians. Metabolite analysis showed that frogs relied more strongly on sulfate conjugation than did Japanese newts and clouded salamanders. Furthermore, urodelan amphibians, newts and salamanders, excreted glucose conjugates of pyrene that were not detected in the anuran amphibians. Kinetic analysis of conjugation by hepatic microsomes and cytosols indicated that differences in excreted metabolites reflected differences in enzymatic activities. Furthermore, pyrenediol (PYDOH) glucoside sulfate was detected in the Japanese newt sample. This novel metabolite has not been reported previously to this report, in which we have identified unique characteristics of amphibians in phase II pyrene metabolism.

  8. New Host and Distribution Records of the Leech Placobdella sophieaeOceguera-Figueroa et al., 2010 (Hirudinida: Glossiphoniidae)

    USGS Publications Warehouse

    Moser, William E.; Bowerman, Jay; Hovingh, Peter; Pearl, Christopher A.; Oceguera-Figueroa, Alajandro

    2014-01-01

    Placobdella sophieae Oceguera-Figueroa et al., 2010 (Hirudinida: Glossiphoniidae) is reported from Oregon, California, and British Columbia for the first time. New hosts reported for P. sophieae include Taricha granulosa (rough-skinned newt), Rana pretiosa (Oregon spotted frog), and Anaxyrus boreas (western toad). Placobdella sophieae exhibits relatively low host specificity and all amphibians occurring in the Pacific Northwest are potential hosts.

  9. 7α-Hydroxypregnenolone, a new key regulator of amphibian locomotion: discovery, progress and prospect.

    PubMed

    Tsutsui, Kazuyoshi; Haraguchi, Shogo; Matsunaga, Masahiro; Koyama, Teppei; Do Rego, Jean-Luc; Vaudry, Hubert

    2012-05-01

    Seasonally-breeding amphibians have served as excellent animal models to investigate the biosynthesis and biological actions of neurosteroids. Previous studies have demonstrated that the brain of amphibians possesses key steroidogenic enzymes and produces pregnenolone, a precursor of steroid hormones, and other various neurosteroids. We recently found that the brain of seasonally-breeding newts actively produces 7α-hydroxypregnenolone, a previously undescribed amphibian neurosteroid. This novel amphibian neurosteroid acts as a neuronal modulator to stimulate locomotor activity in newts. Subsequently, the mode of action of 7α-hydroxypregnenolone has been demonstrated in the newt brain. 7α-Hydroxypregnenolone stimulates locomotor activity through activation of the dopaminergic system. To understand the functional significance of 7α-hydroxypregnenolone in the regulation of locomotor activity, diurnal and seasonal changes in synthesis of 7α-hydroxypregnenolone have also been demonstrated in the newt brain. Melatonin derived from the pineal gland and eyes regulates 7α-hydroxypregnenolone synthesis in the brain, thus inducing diurnal locomotor changes. Prolactin, an adenohypophyseal hormone, regulates 7α-hydroxypregnenolone synthesis in the brain, and also induces seasonal locomotor changes. In addition, 7α-hydroxypregnenolone mediates corticosterone action to increase locomotor activity under stress. This review summarizes the discovery, progress and prospect of 7α-hydroxypregnenolone, a new key regulator of amphibian locomotion.

  10. Identification of 7alpha-hydroxypregnenolone, a novel bioactive amphibian neurosteroid stimulating locomotor activity, and its physiological roles in the regulation of locomotion.

    PubMed

    Tsutsui, Kazuyoshi; Haraguchi, Shogo; Matsunaga, Masahiro; Koyama, Teppei; Do Rego, Jean-Luc; Vaudry, Hubert

    2010-09-01

    We now know that steroids can be synthesized de novo by the brain and the peripheral nervous system. Such steroids are called neurosteroids and de novo neurosteroidogenesis from cholesterol is a conserved property of vertebrate brains. Our studies over the past decade have demonstrated that the brain expresses several kinds of steroidogenic enzymes and produces a variety of neurosteroids in sub-mammalian species. However, neurosteroid biosynthetic pathways in amphibians, as well as other vertebrates may still not be fully mapped. We first found that the newt brain actively produces 7alpha-hydroxypregnenolone, a previously undescribed amphibian neurosteroid. We then demonstrated that 7alpha-hydroxypregnenolone acts as a novel bioactive neurosteroid to stimulate locomotor activity of newt by means of the dopaminergic system. Subsequently, we analyzed the physiological roles of 7alpha-hydroxypregnenolone in the regulation of locomotor activity of newt. This paper summarizes the advances made in our understanding of 7alpha-hydroxypregnenolone, a newly discovered bioactive amphibian neurosteroid stimulating locomotor activity, and its physiological roles in the regulation of locomotion in newt.

  11. Effects of Temperature and Precipitation on Breeding Migrations of Amphibian Species in Southeastern Norway

    PubMed Central

    Dervo, Børre K.; Bærum, Kim Magnus; Skurdal, Jostein; Museth, Jon

    2016-01-01

    To reveal the effects of climate, a generalized linear mixed model was used to explore the variation in onset of spawning migration for the two newt species T. cristatus and L. vulgaris in southern Norway. Amphibians are highly influenced by the physical environment, such as temperature and rainfall. The first migrating newts were observed subsequently to the three first consecutive days with mean temperature close to or above 4°C. Further, migration of L. vulgaris was facilitated at lower temperatures compared to T. cristatus, but the migration was dependent on higher precipitation levels. Northern populations of T. cristatus and L. vulgaris may already benefit from a warmer climate due to increased recruitment and juvenile survival. However, an offset in the migration phenology due to climate change might further alter the recruitment and survival rates with either positive or negative outcome. Thus, variations in migration phenology for newts due to climate change may have implications for management and protection status in many systems. In a general context, we should increase emphasis on protecting newts and support increased populations and distribution. PMID:27239371

  12. Studies on clonogenic hemopoietic cells of vertebrate in space: problems and perspectives

    NASA Astrophysics Data System (ADS)

    Domaratskaya, E. I.; Michurina, T. V.; Bueverova, E. I.; Bragina, E. V.; Nikonova, T. A.; Starostin, V. I.; Khrushchov, N. G.

    Hemopoietic tissues were studied in vertebrates launched aboard the Soviet (Russian) biosatellites ("Cosmos-1129, 1514, 1667, 1887 and 2044"; "Bion-10 and 11") between 1980 and 1996. In the bone marrow of rats exposed to spaceflight conditions, a statistically significant decrease in cell number was revealed in the progenitor cell compartment accounting for the compensatory response of granulocyte—macrophage (CFU-gm) and erythrocyte lineages (BFU-e and CFU-e) and in the compartment of multipotent hemopoietic stem cells (CFU-s), which is responsible for the permanent renewal of hemopoietic tissue. The number of stromal fibroblastic progenitors (CFC-f) in the bone marrow of these rats was also reduced. Apparently, changes in the hemopoietic stroma damage the hemopoietic microenvironment and, hence, may be responsible for changes observed in the hemopoietic tissue proper. Attempts were made to develop methods for analyzing morphologically indiscernible clonogenic hemopoietic cells of newts, and studies on the effects of spaceflight factors on these cells were performed. The results showed that the numbers of clonogenic cells in newts of the flight group newts were significantly lower than in control newts. The data obtained are used as the basis for formulating the problems to be studied, drawing up a program for further research on the effects of spaceflight factors on stem and other clonogenic hemopoietic cells, and developing new experimental models for analyzing stem cells, the state of the hemopoietic stroma, etc.

  13. Slouching toward Bork: The Culture Wars and Self-Criticism in Hip-Hop Music.

    ERIC Educational Resources Information Center

    Ogbar, Jeffrey O. G.

    1999-01-01

    Examined the marginalized voices of hip-hop artists in the culture war debates of the 1990s. Explores the efficacy of those voices and reveals how they differ from the typical parameter of public debate. Discusses the attacks on rap by right wing thinkers, such as Newt Gingrich and Robert Bork. (SLD)

  14. Perspectives: Readings on Contemporary American Government [and] Teacher's Guide.

    ERIC Educational Resources Information Center

    Close Up Foundation, Alexandria, VA.

    This student reader accompanies a teacher's guide of the same name. The essays in this book provide firsthand perspectives on how the federal government works. Essays by President Bill Clinton, Speaker of the House Newt Gingrich, justices of the Supreme Court, journalists, lobbyists, and others who take an active role in this nation's democracy…

  15. Space: The Final Frontier!

    ERIC Educational Resources Information Center

    Roy, Ken

    2003-01-01

    Discusses the importance of laboratory safety in science classrooms. Urges middle school teachers to address class size in an effort to establish and maintain a safe working environment. Answers a teacher's question related to having newts and salamanders in the classroom. (SOE)

  16. Extracellular Control of Limb Regeneration

    NASA Astrophysics Data System (ADS)

    Calve, S.; Simon, H.-G.

    Adult newts possess the ability to completely regenerate organs and appendages. Immediately after limb loss, the extracellular matrix (ECM) undergoes dramatic changes that may provide mechanical and biochemical cues to guide the formation of the blastema, which is comprised of uncommitted stem-like cells that proliferate to replace the lost structure. Skeletal muscle is a known reservoir for blastema cells but the mechanism by which it contributes progenitor cells is still unclear. To create physiologically relevant culture conditions for the testing of primary newt muscle cells in vitro, the spatio-temporal distribution of ECM components and the mechanical properties of newt muscle were analyzed. Tenascin-C and hyaluronic acid (HA) were found to be dramatically upregulated in the amputated limb and were co-expressed around regenerating skeletal muscle. The transverse stiffness of muscle measured in situ was used as a guide to generate silicone-based substrates of physiological stiffness. Culturing newt muscle cells under different conditions revealed that the cells are sensitive to both matrix coating and substrate stiffness: Myoblasts on HA-coated soft substrates display a rounded morphology and become more elongated as the stiffness of the substrate increases. Coating of soft substrates with matrigel or fibronectin enhanced cell spreading and eventual cell fusion.

  17. 76 FR 16233 - Interpretive Rule Regarding Electronic Contributor Redesignations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... Prohibitions, 67 FR 69928, 69934 (Nov. 19, 2002) (Commission declined to eliminate the written signature... by the Commission, 75 FR 42088 (July 20, 2010). Committees are also advised that this interpretive...); 1999-03 (Microsoft PAC); 1995-09 (NewtWatch). During the course of an audit, the Commission...

  18. Effects of Temperature and Precipitation on Breeding Migrations of Amphibian Species in Southeastern Norway.

    PubMed

    Dervo, Børre K; Bærum, Kim Magnus; Skurdal, Jostein; Museth, Jon

    2016-01-01

    To reveal the effects of climate, a generalized linear mixed model was used to explore the variation in onset of spawning migration for the two newt species T. cristatus and L. vulgaris in southern Norway. Amphibians are highly influenced by the physical environment, such as temperature and rainfall. The first migrating newts were observed subsequently to the three first consecutive days with mean temperature close to or above 4°C. Further, migration of L. vulgaris was facilitated at lower temperatures compared to T. cristatus, but the migration was dependent on higher precipitation levels. Northern populations of T. cristatus and L. vulgaris may already benefit from a warmer climate due to increased recruitment and juvenile survival. However, an offset in the migration phenology due to climate change might further alter the recruitment and survival rates with either positive or negative outcome. Thus, variations in migration phenology for newts due to climate change may have implications for management and protection status in many systems. In a general context, we should increase emphasis on protecting newts and support increased populations and distribution. PMID:27239371

  19. Physiological Responses to Salinity Vary with Proximity to the Ocean in a Coastal Amphibian.

    PubMed

    Hopkins, Gareth R; Brodie, Edmund D; Neuman-Lee, Lorin A; Mohammadi, Shabnam; Brusch, George A; Hopkins, Zoë M; French, Susannah S

    2016-01-01

    Freshwater organisms are increasingly exposed to elevated salinity in their habitats, presenting physiological challenges to homeostasis. Amphibians are particularly vulnerable to osmotic stress and yet are often subject to high salinity in a variety of inland and coastal environments around the world. Here, we examine the physiological responses to elevated salinity of rough-skinned newts (Taricha granulosa) inhabiting a coastal stream on the Pacific coast of North America and compare the physiological responses to salinity stress of newts living in close proximity to the ocean with those of newts living farther upstream. Although elevated salinity significantly affected the osmotic (body weight, plasma osmolality), stress (corticosterone), and immune (bactericidal ability) responses of newts, animals found closer to the ocean were generally less reactive to salt stress than those found farther upstream. Our results provide possible evidence for some physiological tolerance in this species to elevated salinity in coastal environments. As freshwater environments become increasingly saline and more stressful, understanding the physiological tolerances of vulnerable groups such as amphibians will become increasingly important to our understanding of their abilities to respond, to adapt, and, ultimately, to survive. PMID:27327182

  20. Biomimetic design of elastomer surface pattern for friction control under wet conditions.

    PubMed

    Huang, Wei; Wang, Xiaolei

    2013-12-01

    In this paper, an observation on the toe pad of a newt was carried out. It was found that the pad surface is covered with an array of polygonal cells separated by channels, similar to those of a tree frog's pad. With this micro-structure, a newt can move on wet and smooth surfaces without slipping. Inspired by the surface structure of newt toe pads, elastic micro-patterned surfaces were fabricated to understand the function of such micro-structures in friction systems. The tribological performance of the patterned surfaces was evaluated using a tribometer. Different tribological performances between micro-dimple and -pillar patterned surfaces were observed. The area density (r) of the micro-pattern is crucial for controlling the friction of the elastic surface. Distinguished from unpatterned and micro-dimple patterned surfaces, the pillar patterned surface with high area density can remain high friction at high sliding speed. It could be one of the reasons of such polygonal structures on newt's toe pads. PMID:23999795

  1. Expression of sexual ornaments in a polymorphic species: phenotypic variation in response to environmental risk.

    PubMed

    Winandy, L; Denoël, M

    2015-05-01

    Secondary sexual traits may evolve under the antagonistic context of sexual and natural selection. In some polymorphic species, these traits are only expressed during the breeding period and are differently expressed in alternative phenotypes. However, it is unknown whether such phenotypes exhibit phenotypic plasticity of seasonal ornamentations in response to environmental pressures such as in the presence of fish (predation risk). This is an important question to understand the evolution of polyphenisms. We used facultative paedomorphosis in newts as a model system because it involves the coexistence of paedomorphs that retain gills in the adult stage with metamorphs that have undergone metamorphosis, but also because newts exhibit seasonal sexual traits. Our aim was therefore to determine the influence of fish on the development of seasonal ornamentation in the two phenotypes of the palmate newt (Lissotriton helveticus). During the entire newt breeding period, we assessed the importance of phenotype and fish presence with an information-theoretic approach. Our results showed that paedomorphs presented much less developed ornamentation than metamorphs and those ornamentations varied over time. Fish inhibited the development of sexual traits but differently between phenotypes: in contrast to metamorphs, paedomorphs lack the phenotypic plasticity of sexual traits to environmental risk. This study points out that internal and external parameters act in complex ways in the expression of seasonal sexual ornamentations and that similar environmental pressure can induce a contrasted evolution in alternative phenotypes. PMID:25847588

  2. Tetrodotoxin: Occurrence in atelopid frogs of Costa Rica.

    PubMed

    Kim, Y H; Brown, G B; Mosher, F A

    1975-07-11

    The potent neurotoxin tetrodotoxin, which has previously been found in puffer fish of the order Tetraordontiformes, a goby (Gobius criniger), and the California newt (Taricha torosa), has now been identified in the skins of frogs of the genus Atelopus from Costa Rica. PMID:1138374

  3. Use of Potential Probiotic Lactic Acid Bacteria (LAB) Biofilms for the Control of Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 Biofilms Formation

    PubMed Central

    Gómez, Natacha C.; Ramiro, Juan M. P.; Quecan, Beatriz X. V.; de Melo Franco, Bernadette D. G.

    2016-01-01

    Use of probiotic biofilms can be an alternative approach for reducing the formation of pathogenic biofilms in food industries. The aims of this study were (i) to evaluate the probiotic properties of bacteriocinogenic (Lactococcus lactis VB69, L. lactis VB94, Lactobacillus sakei MBSa1, and Lactobacillus curvatus MBSa3) and non-bacteriocinogenic (L. lactis 368, Lactobacillus helveticus 354, Lactobacillus casei 40, and Weissela viridescens 113) lactic acid bacteria (LAB) isolated from Brazilian’s foods and (ii) to develop protective biofilms with these strains and test them for exclusion of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. LAB were tested for survival in acid and bile salt conditions, surface properties, biosurfactant production, β-galactosidase and gelatinase activity, antibiotic resistance and presence of virulence genes. Most strains survived exposure to pH 2 and 4% bile salts. The highest percentages of auto-aggregation were obtained after 24 h of incubation. Sixty-seven percentage auto-aggregation value was observed in W. viridescens 113 and Lactobacillus curvatus MBSa3 exhibited the highest co-aggregation (69% with Listeria monocytogenes and 74.6% with E. coli O157:H7), while the lowest co-aggregation was exhibited by W. viridescens 113 (53.4% with Listeria monocytogenes and 38% with E. coli O157:H7). Tests for hemolytic activity, bacterial cell adherence with xylene, and drop collapse confirmed the biosurfactant-producing ability of most strains. Only one strain (L. lactis 368) produced β-galactosidase. All strains were negative for virulence genes cob, ccf, cylLL, cylLs, cyllM, cylB, cylA and efaAfs and gelatinase production. The antibiotic susceptibility tests indicated that the MIC for ciprofloxacin, clindamycin, gentamicin, kanamycin, and streptomycin did not exceed the epidemiological cut-off suggested by the European Food Safety Authority. Some strains were resistant to one or more antibiotics and

  4. Use of Potential Probiotic Lactic Acid Bacteria (LAB) Biofilms for the Control of Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 Biofilms Formation.

    PubMed

    Gómez, Natacha C; Ramiro, Juan M P; Quecan, Beatriz X V; de Melo Franco, Bernadette D G

    2016-01-01

    Use of probiotic biofilms can be an alternative approach for reducing the formation of pathogenic biofilms in food industries. The aims of this study were (i) to evaluate the probiotic properties of bacteriocinogenic (Lactococcus lactis VB69, L. lactis VB94, Lactobacillus sakei MBSa1, and Lactobacillus curvatus MBSa3) and non-bacteriocinogenic (L. lactis 368, Lactobacillus helveticus 354, Lactobacillus casei 40, and Weissela viridescens 113) lactic acid bacteria (LAB) isolated from Brazilian's foods and (ii) to develop protective biofilms with these strains and test them for exclusion of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. LAB were tested for survival in acid and bile salt conditions, surface properties, biosurfactant production, β-galactosidase and gelatinase activity, antibiotic resistance and presence of virulence genes. Most strains survived exposure to pH 2 and 4% bile salts. The highest percentages of auto-aggregation were obtained after 24 h of incubation. Sixty-seven percentage auto-aggregation value was observed in W. viridescens 113 and Lactobacillus curvatus MBSa3 exhibited the highest co-aggregation (69% with Listeria monocytogenes and 74.6% with E. coli O157:H7), while the lowest co-aggregation was exhibited by W. viridescens 113 (53.4% with Listeria monocytogenes and 38% with E. coli O157:H7). Tests for hemolytic activity, bacterial cell adherence with xylene, and drop collapse confirmed the biosurfactant-producing ability of most strains. Only one strain (L. lactis 368) produced β-galactosidase. All strains were negative for virulence genes cob, ccf, cylLL, cylLs, cyllM, cylB, cylA and efaAfs and gelatinase production. The antibiotic susceptibility tests indicated that the MIC for ciprofloxacin, clindamycin, gentamicin, kanamycin, and streptomycin did not exceed the epidemiological cut-off suggested by the European Food Safety Authority. Some strains were resistant to one or more antibiotics and resistance

  5. Developmental alterations in centrosome integrity contribute to the post-mitotic state of mammalian cardiomyocytes.

    PubMed

    Zebrowski, David C; Vergarajauregui, Silvia; Wu, Chi-Chung; Piatkowski, Tanja; Becker, Robert; Leone, Marina; Hirth, Sofia; Ricciardi, Filomena; Falk, Nathalie; Giessl, Andreas; Just, Steffen; Braun, Thomas; Weidinger, Gilbert; Engel, Felix B

    2015-01-01

    Mammalian cardiomyocytes become post-mitotic shortly after birth. Understanding how this occurs is highly relevant to cardiac regenerative therapy. Yet, how cardiomyocytes achieve and maintain a post-mitotic state is unknown. Here, we show that cardiomyocyte centrosome integrity is lost shortly after birth. This is coupled with relocalization of various centrosome proteins to the nuclear envelope. Consequently, postnatal cardiomyocytes are unable to undergo ciliogenesis and the nuclear envelope adopts the function as cellular microtubule organizing center. Loss of centrosome integrity is associated with, and can promote, cardiomyocyte G0/G1 cell cycle arrest suggesting that centrosome disassembly is developmentally utilized to achieve the post-mitotic state in mammalian cardiomyocytes. Adult cardiomyocytes of zebrafish and newt, which are able to proliferate, maintain centrosome integrity. Collectively, our data provide a novel mechanism underlying the post-mitotic state of mammalian cardiomyocytes as well as a potential explanation for why zebrafish and newts, but not mammals, can regenerate their heart. PMID:26247711

  6. NASDA aquatic animal experiment facilities for Space Shuttle.

    PubMed

    Sakimura, T; Suzuki, T; Matsubara, S; Uchida, S; Kato, M; Tanemura, R; Honda, S

    1999-12-01

    National Space Development Agency of Japan (NASDA) has been developed aquatic animal experiment facilities for space experiments using NASA Space Shuttle. Vestibular Function Experiment Unit (VFEU) has been firstly designed and developed for Spacelab-J mission (STS-47), and 8 days space experiment with carp has been performed. Following, the VFEU, Aquatic Animal Experiment Unit (AAEU) has been developed to accommodate small aquatic animals second International Microgravity Laboratory mission (IML-2, STS-65). Four kinds of space experiments with goldfish, medaka, newt, and newt eggs have been performed for 15 days mission duration. Then, VFEU has been improved to accommodate marine fish under low temperature condition for Neurolab (STS-90) and STS-95 missions. 17 days (STS-90) and 9 days (STS-95) experiments with oyster toadfish have been performed by using the VFEU. This report summarizes the outline of these aquatic animal experiment facilities.

  7. Correlations of geographic distribution and temperature of embryonic development with the nuclear DNA content in the Salamandridae (Urodela, Amphibia).

    PubMed

    Litvinchuk, Spartak N; Rosanov, Jury M; Borkin, Leo J

    2007-04-01

    We used flow cytometry to measure the nuclear DNA content in erythrocytes of 27 salamandrid species. Across these species, diploid genome size varied more than 2 fold (51.3-104.4 pg). According to genome size and geographic distribution, 3 groups of newt species were recognized: West Palearctics with smaller amounts of nuclear DNA; Nearctic, with intermediate values; and East Asiatic, with higher genome sizes. Viviparous West Palearctic salamanders differed from most of the oviparous West Palearctic newts in possessing larger genome sizes. The nuclear DNA content strongly correlates with species range limits. At the same temperature, embryos of salamandrid species with larger genome sizes have a markedly longer developmental time than those with smaller genomes. We present an analysis of the relationships between the amount of nuclear DNA and water temperature at the breeding sites.

  8. Neoteny and progenesis as two heterochronic processes involved in paedomorphosis in Triturus alpestris (Amphibia: Caudata).

    PubMed Central

    Denoël, M; Joly, P

    2000-01-01

    Current theories on the evolution of paedomorphosis suppose that several ontogenetic pathways have appeared according to different selective pressures. The aim of this study was to find out whether two distinct processes can lead to paedomorphosis in the Alpine newt, Triturus alpestris. In this respect, we compared age structures of paedomorphic and metamorphic individuals in two newt populations where the two forms lived syntopically. Whereas paedomorphosis resulted in a slower rate of somatic development in one population, it resulted in an acceleration of sexual maturation in the other population. These processes correspond to neoteny and progenesis, respectively. These results suggest that phenotypic plasticity can result from contrasted ontogenetic pathways between two populations of the same species. They give support to models that consider gonadic development as the target of selection under different environmental pressures. PMID:10983835

  9. Structure of rat acidic fibroblast growth factor at 1.4 Å resolution

    SciTech Connect

    Kulahin, Nikolaj; Kochoyan, Arthur; Berezin, Vladimir; Bock, Elisabeth; Gajhede, Michael

    2007-02-01

    The structure of rat acidic fibroblast growth factor was determined and compared with those of human, bovine and newt origin. The rat and human structures were found to be very similar. Fibroblast growth factors (FGFs) constitute a family of 22 structurally related heparin-binding polypeptides that are involved in the regulation of cell growth, survival, differentiation and migration. Here, a 1.4 Å resolution X-ray structure of rat FGF1 is presented. Two molecules are present in the asymmetric unit of the crystal and they coordinate a total of five sulfate ions. The structures of human, bovine and newt FGF1 have been published previously. Human and rat FGF1 are found to have very similar structures.

  10. Developmental alterations in centrosome integrity contribute to the post-mitotic state of mammalian cardiomyocytes.

    PubMed

    Zebrowski, David C; Vergarajauregui, Silvia; Wu, Chi-Chung; Piatkowski, Tanja; Becker, Robert; Leone, Marina; Hirth, Sofia; Ricciardi, Filomena; Falk, Nathalie; Giessl, Andreas; Just, Steffen; Braun, Thomas; Weidinger, Gilbert; Engel, Felix B

    2015-08-06

    Mammalian cardiomyocytes become post-mitotic shortly after birth. Understanding how this occurs is highly relevant to cardiac regenerative therapy. Yet, how cardiomyocytes achieve and maintain a post-mitotic state is unknown. Here, we show that cardiomyocyte centrosome integrity is lost shortly after birth. This is coupled with relocalization of various centrosome proteins to the nuclear envelope. Consequently, postnatal cardiomyocytes are unable to undergo ciliogenesis and the nuclear envelope adopts the function as cellular microtubule organizing center. Loss of centrosome integrity is associated with, and can promote, cardiomyocyte G0/G1 cell cycle arrest suggesting that centrosome disassembly is developmentally utilized to achieve the post-mitotic state in mammalian cardiomyocytes. Adult cardiomyocytes of zebrafish and newt, which are able to proliferate, maintain centrosome integrity. Collectively, our data provide a novel mechanism underlying the post-mitotic state of mammalian cardiomyocytes as well as a potential explanation for why zebrafish and newts, but not mammals, can regenerate their heart.

  11. Comparative genotoxicity of halogenated acetic acids found in drinking water.

    PubMed

    Giller, S; Le Curieux, F; Erb, F; Marzin, D

    1997-09-01

    Three short-term assays (SOS chromotest, Ames fluctuation test and newt micronucleus test) were performed to detect the genotoxic activity of organohalides, compounds likely to be found in chlorinated and/or ozonated drinking water: monochloro-, dichloro- and trichloroacetic acids and monobromo-, dibromo- and tribromoacetic acids. With the SOS chromotest, only three of the chemicals studied (dichloroacetic acid, dibromo- and tribromoacetic acids) were found to induce primary DNA damage in Escherichia coli PQ 37. In the Ames fluctuation test, all the compounds except monochloroacetic acid showed mutagenic activity in Salmonella typhimurium strain TA100. In these two in vitro tests, a good correlation between increasing number of substituents and decreasing mutagenicity was observed. Namely, the toxicity of brominated and chlorinated acetic acids decreased when the number of substituents increased. The newt micronucleus test detected a weak clastogenic effect on the peripheral blood erythrocytes of Pleurodeles waltl larvae for trichloroacetic acid only.

  12. [Peptide-containing fraction from a culture medium of Fusarium sambucinum: composition and biological effects].

    PubMed

    Bogdanov, V V; Fatkulina, É F; Berezin, B B; Il'ina, A P; Iamskova, V P; Iamskov, I A

    2014-01-01

    The culture fluid of the fungus Fusarium sambucinum was investigated for the presence of new peptide-containing bioregulators, previously identified in various mammalian and plant tissues. A fraction containing peptides with molecular weights from 1000 to 2000 Da, which exhibited specific membranotropic activity and a number of physical and chemical properties characteristic of this group of bioregulators, was obtained. The effects of this fraction on the model roller organotypic cultivation of liver tissue of the Pleurodeles waltl newt in vitro were investigated for the first time. This fraction caused the additional activation of pigmented liver cells of newt (analogues to Kupffer cells of the liver of mammals) and provided the maintenance of cell-cell adhesive interactions in tissues. The results show that a new group of peptide bioregulators was present in the culture medium of the fungus F. sambucinum.

  13. Development of Gravity-Sensing Organs in Altered Gravity

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Gao, W. Y.; Harrison, J. L.; Hejl, R.

    1996-01-01

    Experiments are described in which the development of the gravity-sensing organs was studied in newt larvae reared in micro-g on the IML-2 mission and in Aplysia embryos and larvae reared on a centrifuge at 1 to 5 g. In Aplysia embryos, the statolith (single dense mass on which gravity and linear acceleration act) was reduced in size in a graded fashion at increasing g. In early post-metamorphic Aplysia or even in isolated statocysts from such animals, the number of statoconia produced is reduced at high gravity Newt larvae launched before any of the otoconia were formed and reared for 15 days in micro-gravity had nearly adult labyrinths at the end of the IML-2 mission. The otoliths of the saccule and utricle were the same size in flight and ground-reared larvae. However, the system of aragonitic otoconia produced in the endolymphatic sac in amphibians was much larger and developed earlier in the flight-reared larvae. At later developmental stages, the aragonitic otoconia enter and fill the saccule. One flight-reared larva was maintained for nine months post-flight and the size of the saccular otolith, as well as the volume of otoconia within the endolymphatic sac, were considerably larger than in age-matched, ground-reared newts. This suggests that rearing in micro-gravity initiates a process that continues for several months after introduction to 1-g, which greatly increases the volume of otoconia. The flight-reared animal had abnormal posture, pointing its head upward, whereas normal ground-reared newts always keep their head horizontal. This suggests that rearing for even a short period in micro-gravity can have lasting functional consequences in an animal subsequently reared in 1-g conditions on Earth.

  14. New animal model to study epigenetic mechanisms mediating altered gravity effects upon cell growth and morphogenesis

    NASA Astrophysics Data System (ADS)

    Grigoryan, Eleonora N.; Dvorochkin, Natasha; Radugina, Elena A.; Poplinskaya, Valentina; Novikova, Julia; Almeida, Eduardo

    The gravitational field and its variations act as a major environmental factor that can impact morphogenesis developing through epigenetic molecular mechanisms. The mechanisms can be thoroughly investigated by using adequate animal models that reveal changes in the morpho-genesis of a growing organ as a function of gravitational effects. Two cooperative US/Russian experiments on Foton-M2 (2005) and Foton-M3 (2007) were the first to demonstrate differences in the shape of regenerating tails of space-flown and ground control newts. The space-flown and aquarium (simulated microgravity) animals developed lancet-shaped tails whereas 1 g con-trols (kept in space-type habitats) showed hook-like regenerates. These visual observations were supported by computer-aided processing of the images and statistical analysis of the results. Morphological examinations and cell proliferation measurements using BrdU demon-strated dorsal-ventral asymmetry as well as enhanced epithelial growth on the dorsal area of regenerating tails in 1 g newts. These findings were reproduced in laboratory tests on newts kept at 1 g and in large water tanks at cut g. The 1 g animals showed statistically significant deviations of the lancet-like tail shape typically seen in aquarium animals. Such modifications were found as early as regeneration stages III-IV and proved irreversible. The authors believe that the above phenomenon detected in newts used in many space experiments can serve as an adequate model for studying molecular mechanisms underlying gravitational effects upon animal morphogenesis.

  15. Regeneration of organs and tissues in lower vertebrates during and after space flight

    NASA Astrophysics Data System (ADS)

    Mitashov, V. I.; Brushlinskaya, N. V.; Grigoryan, E. N.; Tuchkova, S. Ya.; Anton, H. J.

    In this paper most important data obtained in studies on the effect of space flight conditions on regeneration in the adult newt are summarized. We demonstrate a phenomenon of synchronization of limb and lens regeneration and increase in its rate during and after space flight. We also describe a peculiarities of cell proliferation in lens, limb and tail regenerates and of the process of minced muscle regeneration.

  16. Three-dimensional holographic reconstruction of two-dimensional image information from serial sections and its applications in biomedicine

    NASA Astrophysics Data System (ADS)

    Zhou, Guo-Ping

    1985-02-01

    An experimental study to synthesize holographically two-dimensional projections of serial sections at various depths into three-dimensional images is described. The effects caused by the position, size and resolution of virtual images during reconstruction are analysed, and the advantages and limitations of this method are discussed. An application of this experimental method — the three-dimensional reconstruction of serial sections of a newt embryo — is presented.

  17. Program Aids Analysis And Optimization Of Design

    NASA Technical Reports Server (NTRS)

    Rogers, James L., Jr.; Lamarsh, William J., II

    1994-01-01

    NETS/ PROSSS (NETS Coupled With Programming System for Structural Synthesis) computer program developed to provide system for combining NETS (MSC-21588), neural-network application program and CONMIN (Constrained Function Minimization, ARC-10836), optimization program. Enables user to reach nearly optimal design. Design then used as starting point in normal optimization process, possibly enabling user to converge to optimal solution in significantly fewer iterations. NEWT/PROSSS written in C language and FORTRAN 77.

  18. Development of gravity-sensing organs in altered gravity

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Gao, W. Y.; Harrison, J. L.; Hejl, R.

    1997-01-01

    Experiments are described in which the development of the gravity-sensing organs was studied in newt larvae reared in microgravity on the IML-2 mission and in Aplysia embryos and larvae reared on a centrifuge at 1 to 5 g. In Aplysia embryos, the statolith (single dense mass on which gravity and linear acceleration act) was reduced in size in a graded fashion at increasing g. In early post-metamorphic Aplysia or even in isolated statocysts from such animals, the number of statoconia produced is reduced at high g. Newt larvae launched before any of the otoconia were formed and reared for 15 days in microgravity had nearly adult labyrinths at the end of the IML-2 mission. The otoliths of the saccule and utricle were the same size in flight and ground-reared larvae. However, the system of aragonitic otoconia produced in the endolymphatic sac in amphibians was much larger and developed earlier in the flight-reared larvae. At later developmental stages, the aragonitic otoconia enter and fill the saccule. One flight-reared larva was maintained for nine months post-flight and the size of the saccular otolith, as well as the volume of otoconia within the endolymphatic sac, were considerably larger than in age-matched, ground-reared newts. This suggests that rearing in microgravity initiates a process that continues for several months after introduction to 1-g, which greatly increases the volume of otoconia. The flight-reared animal had abnormal posture, pointing its head upward, whereas normal ground-reared newts always keep their head horizontal. This suggests that rearing for even a short period in microgravity can have lasting functional consequences in an animal subsequently reared in 1-g conditions on Earth.

  19. Interactive influence of biotic and abiotic cues on the plasticity of preferred body temperatures in a predator-prey system.

    PubMed

    Smolinský, Radovan; Gvoždík, Lumír

    2012-09-01

    The ability to modify phenotypes in response to heterogeneity of the thermal environment represents an important component of an ectotherm's non-genetic adaptive capacity. Despite considerable attention being dedicated to the study of thermally-induced developmental plasticity, whether or not interspecific interactions shape the plastic response in both a predator and its prey remains unknown. We tested several predictions about the joint influence of predator/prey scents and thermal conditions on the plasticity of preferred body temperatures (T (p)) in both actors of this interaction, using a dragonfly nymphs-newt larvae system. Dragonfly nymphs (Aeshna cyanea) and newt eggs (Ichthyosaura alpestris) were subjected to fluctuating cold and warm thermal regimes (7-12 and 12-22°C, respectively) and the presence/absence of a predator or prey chemical cues. Preferred body temperatures were measured in an aquatic thermal gradient (5-33°C) over a 24-h period. Newt T (p) increased with developmental temperature irrespective of the presence/absence of predator cues. In dragonflies, thermal reaction norms for T (p) were affected by the interaction between temperature and prey cues. Specifically, the presence of newt scents in cold regime lowered dragonfly T (p). We concluded that predator-prey interactions influenced thermally-induced plasticity of T (p) but not in a reciprocal fashion. The occurrence of frequency-dependent thermal plasticity may have broad implications for predator-prey population dynamics, the evolution of thermal biology traits, and the consequences of sustaining climate change within ecological communities.

  20. STS-65 onboard: IML-2

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Onboard Space Shuttle Columbia (STS-65) Mission specialist Leroy Chiao is seen in the International Microgravity Laboratory 2 (IML-2) spacelab science moduel in front of Rack 3 and above center aisle equipment. Chiao has just made an observation of the goldfish container (silver apparatus on left beween his right hand and knee) . The Rack 3 Aquatic Animal Experiment Unit (AAEU) also contains Medaka and newts. Chiao joined five other NASA astronauts and a Japanese payload specialist for two weeks of experimenting.

  1. Evidence of light-dependent magnetic compass orientation in urodele amphibian larvae.

    PubMed

    Diego-Rasilla, Francisco J; Luengo, Rosa M; Phillips, John B

    2015-09-01

    Experiments were conducted to investigate whether larval palmate newts undertake orientation toward or away from the home shoreline (y-axis orientation) using the geomagnetic field to steer the most direct route, and if they accomplish this task through a light-dependent magnetoreception mechanism similar to that found in anuran tadpoles and adult newts. Larval palmate newts trained and then tested under full-spectrum light showed bimodal magnetic compass orientation that coincided with the magnetic direction of the trained y-axis. In contrast, larvae trained under long-wavelength (≥500nm) light and then tested under full-spectrum light displayed bimodal orientation perpendicular to the trained y-axis direction. These results offer evidence for the use of magnetic compass cues in orienting urodele amphibian larvae, and provide additional support for the light-dependent magnetoreception mechanism since they are in complete agreement with earlier studies showing that the observed 90° shift in the direction of magnetic compass orientation under long-wavelength light (≥500nm) is due to a direct effect of light on the underlying magnetoreception mechanism. This study is the first to provide evidence of a light-dependent magnetic compass in larval urodeles. PMID:25981491

  2. Individual fluctuations in toxin levels affect breeding site fidelity in a chemically defended amphibian.

    PubMed

    Bucciarelli, Gary M; Green, David B; Shaffer, H Bradley; Kats, Lee B

    2016-05-25

    Behaviours that influence habitat selection strongly determine species movement patterns. One component of animal behaviour that largely influences movement patterns and habitat choice is site fidelity. California newts (family Salamandridae) demonstrate remarkable site fidelity, typically homing to the same pool of a stream each breeding season. Individuals often occupy a specific pool throughout the breeding season, but some males shift among breeding pools, altering their set of potential mates, competitors, and predators. In this study, we measured dermal concentrations of the chemical defence compound tetrodotoxin (TTX) in recaptured male California newts (Taricha torosa) over five breeding seasons to evaluate whether relative TTX concentrations are associated with breeding site fidelity in the field. Our five years of field sampling indicates that TTX concentrations of individuals and group means fluctuate tremendously, implying that TTX is not a stable phenotypic trait. Despite such fluctuations, we found that an individual's relative TTX concentration explains fidelity to a breeding pool and suggests that newts may be able to assess both their own concentrations of TTX and that of conspecifics to make decisions about remaining in or abandoning a breeding pool. These results provide us a novel dimension to chemical defence phenotypes in nature and their ecological consequences, potentially requiring a re-evaluation of the coevolutionary dynamics of predation pressure on toxin-laden organisms. PMID:27194704

  3. Parasite transmission in complex communities: predators and alternative hosts alter pathogenic infections in amphibians.

    PubMed

    Orlofske, Sarah A; Jadin, Robert C; Preston, Daniel L; Johnson, Pieter T J

    2012-06-01

    While often studied in isolation, host-parasite interactions are typically embedded within complex communities. Other community members, including predators and alternative hosts, can therefore alter parasite transmission (e.g., the dilution effect), yet few studies have experimentally evaluated more than one such mechanism. Here, we used data from natural wetlands to design experiments investigating how alternative hosts and predators of parasites mediate trematode (Ribeiroia ondatrae) infection in a focal amphibian host (Pseudacris regilla). In short-term predation bioassays involving mollusks, zooplankton, fish, larval insects, or newts, four of seven tested species removed 62-93% of infectious stages. In transmission experiments, damselfly nymphs (predators) and newt larvae (alternative hosts) reduced infection in P. regilla tadpoles by -50%, whereas mosquitofish (potential predators and alternative hosts) did not significantly influence transmission. Additional bioassays indicated that predators consumed parasites even in the presence of alternative prey. In natural wetlands, newts had similar infection intensities as P. regilla, suggesting that they commonly function as alternative hosts despite their unpalatability to downstream hosts, whereas mosquitofish had substantially lower infection intensities and are unlikely to function as hosts. These results underscore the importance of studying host-parasite interactions in complex communities and of broadly linking research on predation, biodiversity loss, and infectious diseases.

  4. Detrimental effect of temperature increase on the fitness of an amphibian ( Lissotriton helveticus)

    NASA Astrophysics Data System (ADS)

    Galloy, Valérie; Denoël, Mathieu

    2010-03-01

    Increases of global temperatures have resulted in measurable shifts in the distribution, phenology and survival of some plant and animal species. However, the mechanisms showing links between global warming and biodiversity declines remain unclear. The aim of this study was to examine whether a key parameter of fitness, i.e. offspring number, could be affected by a temperature increase. To this end, we compared egg-laying traits at naturally occurring temperatures (14 °C, 18 °C and 22 °C) in palmate newts, Lissotriton helveticus. Our study suggests that water temperature increase has a negative effect on the fecundity of female newts. Females lay half as many eggs at high temperatures as they do at low temperatures, which results in a lower number of hatchlings. This study shows that global warming would affect amphibian populations. It complements other studies in pointing out that changes in phenology may not be driven only by warmer earlier temperatures but also by counter-selection during late-breeding, particularly in long-term breeders such as newts. More experimental studies should be carried out to understand the complex consequences of global warming and the proximate mechanisms of amphibian decline.

  5. The benefits of heterospecific oophagy in a top predator

    NASA Astrophysics Data System (ADS)

    Denoël, Mathieu; Demars, Bertrand

    2008-07-01

    Oophagy is a behavioural pattern that has been found in a large variety of predator species in the animal kingdom. In contrast to other modes of feeding, it is peculiar in that it involves the detection, capture and ingestion of immobile prey. Several hypotheses have been proposed to explain the evolutionary origin and persistence of this pattern, but they have rarely been tested. The aim of this study was to compare the benefits of a heterospecific oophagous tactic over a non-oophageous diet in terms of biomass intake. To this end, stomach contents were gathered by flushing the stomachs of male and female Alpine newts ( Mesotriton alpestris) found in forestry ruts (i.e. pools caused by traffic) during their reproductive period. Prey items were identified, classified into functional categories and their dry mass determined. Frog ( Rana temporaria) eggs are valuable prey items that give a higher biomass intake to individuals foraging on them than on those relying on invertebrates. Both sexes of newts practice oophagy but frog eggs are a transient resource that is only available during a part of their aquatic phase. Consequently, the newts adjust their diet to invertebrate predation later in the season after the peak of the frogs' breeding season. Oophagy is thus facultative and not obligate in the study species. The correlated occurrence of prey and predator, similarities between frog eggs and mobile potential prey (tadpoles), and high resource intake are all in favour of the occurrence and persistence of an oophagous feeding tactic.

  6. Variation in winter metabolic reduction between sympatric amphibians.

    PubMed

    Podhajský, Luděk; Gvoždík, Lumír

    2016-11-01

    Distribution and abundance of temperate ectotherms is determined, in part, by the depletion of their limited caloric reserves during wintering. The magnitude of winter energy drain depends on the species-specific capacity to seasonally modify the minimal maintenance costs. We examined seasonal variation of minimum oxygen consumption between two newt species, Ichthyosaura alpestris and Lissotriton vulgaris. Oxygen consumption was measured in both species during their active season (daily temperature range=12-22°C) and wintering period (4°C) at 4°C and 8°C. The seasonal reduction in metabolic rates differed between species and experimental temperatures. Wintering newts reduced their metabolic rates at 4°C and 8°C in I. alpestris, but only at 8°C in L. vulgaris. Both species reduced the thermal sensitivity of oxygen consumption during wintering. Theoretical calculations of winter depletion of caloric reserves under various thermal conditions revealed that seasonal metabolic reduction is more effective in I. alpestris than in L. vulgaris, and its effectiveness will increase with the proportion of warmer days during wintering period. The variation in winter metabolic reduction between sympatric newt species potentially contributes to their distribution patterns and population dynamics under climate change. PMID:27418441

  7. Evidence of light-dependent magnetic compass orientation in urodele amphibian larvae.

    PubMed

    Diego-Rasilla, Francisco J; Luengo, Rosa M; Phillips, John B

    2015-09-01

    Experiments were conducted to investigate whether larval palmate newts undertake orientation toward or away from the home shoreline (y-axis orientation) using the geomagnetic field to steer the most direct route, and if they accomplish this task through a light-dependent magnetoreception mechanism similar to that found in anuran tadpoles and adult newts. Larval palmate newts trained and then tested under full-spectrum light showed bimodal magnetic compass orientation that coincided with the magnetic direction of the trained y-axis. In contrast, larvae trained under long-wavelength (≥500nm) light and then tested under full-spectrum light displayed bimodal orientation perpendicular to the trained y-axis direction. These results offer evidence for the use of magnetic compass cues in orienting urodele amphibian larvae, and provide additional support for the light-dependent magnetoreception mechanism since they are in complete agreement with earlier studies showing that the observed 90° shift in the direction of magnetic compass orientation under long-wavelength light (≥500nm) is due to a direct effect of light on the underlying magnetoreception mechanism. This study is the first to provide evidence of a light-dependent magnetic compass in larval urodeles.

  8. How the transition frequencies of microtubule dynamic instability (nucleation, catastrophe, and rescue) regulate microtubule dynamics in interphase and mitosis: analysis using a Monte Carlo computer simulation.

    PubMed Central

    Gliksman, N R; Skibbens, R V; Salmon, E D

    1993-01-01

    Microtubules (MTs) in newt mitotic spindles grow faster than MTs in the interphase cytoplasmic microtubule complex (CMTC), yet spindle MTs do not have the long lengths or lifetimes of the CMTC microtubules. Because MTs undergo dynamic instability, it is likely that changes in the durations of growth or shortening are responsible for this anomaly. We have used a Monte Carlo computer simulation to examine how changes in the number of MTs and changes in the catastrophe and rescue frequencies of dynamic instability may be responsible for the cell cycle dependent changes in MT characteristics. We used the computer simulations to model interphase-like or mitotic-like MT populations on the basis of the dynamic instability parameters available from newt lung epithelial cells in vivo. We started with parameters that produced MT populations similar to the interphase newt lung cell CMTC. In the simulation, increasing the number of MTs and either increasing the frequency of catastrophe or decreasing the frequency of rescue reproduced the changes in MT dynamics measured in vivo between interphase and mitosis. Images PMID:8298190

  9. Survey of intermediate filament proteins in optic nerve and spinal cord: evidence for differential expression.

    PubMed

    Quitschke, W; Jones, P S; Schechter, N

    1985-05-01

    The distribution of intermediate filament proteins in optic nerve and spinal cord from rat, hamster, goldfish, frog, and newt were analyzed by two-dimensional gel electrophoresis. General as well as specific monoclonal and polyclonal antibodies were reacted against putative intermediate filament proteins. In vitro incubations of excised optic nerve in the presence of [35S]methionine distinguished between neuronal and nonneuronal intermediate filament proteins. The proteins of the intermediate filament complex in the two tissues for rat and hamster were similar. The typical neurofilament triplet and glial fibrillary acidic protein (GFAP) were observed. Vimentin was more concentrated in the optic nerve than in the spinal cord. The goldfish, newt, and frog contained neurofilament proteins in the 145-150K range and in the 70-85K range. In addition, predominant neurofilament proteins in the 58-62K molecular-weight range were found in all three species. In contrast to mammalian species, the goldfish, newt, and frog displayed extensive heterogeneity between optic nerve and spinal cord in the expression of both neuronal and nonneuronal intermediate filament proteins. The distinctive presence of low-molecular-weight intermediate filament proteins and their high concentration in the optic nerve and spinal cord of these nonmammalian vertebrates is discussed in terms of neuronal development and regeneration.

  10. Histological changes, apoptosis and metallothionein levels in Triturus carnifex (Amphibia, Urodela) exposed to environmental cadmium concentrations.

    PubMed

    Capaldo, Anna; Gay, Flaminia; Scudiero, Rosaria; Trinchella, Francesca; Caputo, Ivana; Lepretti, Marilena; Marabotti, Anna; Esposito, Carla; Laforgia, Vincenza

    2016-04-01

    The aim of this study was to verify if the freshwater safety values established from the European Community (1998) and the Italian Ministry of Health (2001) for cadmium (44.5nM/L in drinking water and 178nM/L in sewage waters) were safe for amphibians, since at these same concentrations cadmium induced endocrine disruption in the newt Triturus carnifex. Adult male specimens of T. carnifex were exposed daily to cadmium (44.5nM/L and 178nM/L as CdCl2, nominal concentrations), respectively, during 3- and 9-months; at the same time, control newts were exposed to tap water only. The accumulation of cadmium in the skin, liver and kidney, the levels of metallothioneins in the skin and the liver, the expression of metallothionein mRNA in the liver, as well as the presence of histological alterations and of apoptosis in the target organs were evaluated. The 9-months exposure induced cadmium accumulation in all the tissues examined; moreover, histological changes were observed in all the tissues examined, irrespective of the dose or the time of exposure. Apoptosis was only detected in the kidney, whereas metallothioneins and metallothionein mRNA did not increase. This study demonstrates that the existing chronic water quality criterion established for cadmium induces in the newt T. carnifex cadmium accumulation and histological alterations in the target organs examined. Together with our previous results, showing that, at these same concentrations, cadmium induced endocrine disruption, the present results suggest that the existing chronic water quality criterion for cadmium appears to be not protective of amphibians. PMID:26851569

  11. Static friction of biomimetic surface microstructure of PDMS under wet and dry conditions

    NASA Astrophysics Data System (ADS)

    Yu, Haiwu; Jia, Hongduo; Gong, Ling; Li, Rong; Wang, Caiping; Wang, Xiaojie

    2016-04-01

    Smooth adhesive pad found among arthropods, amphibians, particularly tree frogs, are usually covered with surface microstructure of different shape to enhance the attachment abilities on the smooth substrate. During the last decade, it has gained more attentions in the development of anti-slippery systems by mimicking these unique characteristics. In this paper, we studied a new amphibian species newt by observing their climbing abilities on wet and dry vertical smooth surface, and found that the newts can even hang on the surface with an inclination angle more than 90° without falling. We investigated the toe pad micro-structured surface of the newt by using scanning electron microscopy (SEM), and found that an array of hexagonal cells with micro-ridges on cell borders exists for the larvae; while an array of hexagonal cells separated by microgrooves is for the adult. Inspired by these features, the biomimetic micro-structured surfaces were fabricated using a soft elastomeric material polydimethysiloxane (PDMS). Four different microstructures were chosen to study their tribological properties with a solid substrate under wet and dry conditions. The patterns of the microstructures include round pillar, hexagonal pillar, round pillars surrounded by a closed hexagonal ridge, and round pillars surrounded by a semi-closed hexagonal ridge. The static friction tests were carried out using the multi-functional surface meter TYPE12. The results showed that the area ratio of the micro pillar plays a major role in enhancing the static friction for both wet and dry conditions, while the numerical density of the micro pillar has less effect on the friction enhancement. Among the four kind specimens, the specimen with hexagonal pillars would increase the static friction more than others at the same test conditions when the pillar area ratio is lower than 40%.

  12. Regeneration of eye tissues is modulated by altered levels of gravity at 1g, 2g, and in microgravity during spaceflight

    NASA Astrophysics Data System (ADS)

    Grigoryan, Eleonora; Almeida, Eduardo; Mitashov, Victor

    The pursuit of human space exploration requires detailed knowledge of microgravity-related changes in fundamental biological processes, and their effects on health. Normal regeneration of organs and tissues is one such fundamental process that allows maintenance of vitality and function of living organisms. Animal models of tissue regeneration include the newt (Pleurodeles waltl, Urodela) eye, which has been extensively used by our team in Russian Bion and Foton microgravity experiments since 1985, and in recent NASA 2.5 meter diameter centrifuge hypergravity experiments. In total, these experiments allow us to draw several broad conclusions: Newt lens regeneration is significantly altered in microgravity and hypergravity relative to 1g controls. Lenses formed in microgravity are larger and more developed than those regenerated in 1g controls; Microgravity alterations of lens regeneration can persist after spaceflight, and continue to affect repeated removal and regeneration of the lens after return to 1g; Microgravity increases the numbers of early stage regenerative proliferating BrdU-labeled cells in dorsal iris progenitors and in the lens regenerate. Regeneration under hypergravity conditions at 2g inhibits lens regeneration, and often causes retinal detachment. Molecular mechanisms regulating lens regeneration rate include FGF2 signaling, (a key pathway for eye tissue development and regeneration), and an expression of stress-related proteins - HSPs. In conclusion, regeneration of lens and other eye tissues in the newt is sensitive to, and regulated by the level of gravity mechanotransduction and developmental signaling pathways, with microgravity favoring stem cell progenitor proliferation, and gravity at 1g promoting terminal differentiation, while hypergravity at 2g often causes damage of delicate regenerating tissues.

  13. ADAR-related activation of adenosine-to-inosine RNA editing during regeneration.

    PubMed

    Witman, Nevin M; Behm, Mikaela; Ohman, Marie; Morrison, Jamie I

    2013-08-15

    Urodele amphibians possess an amazing regenerative capacity that requires the activation of cellular plasticity in differentiated cells and progenitor/stem cells. Many aspects of regeneration in Urodele amphibians recapitulate development, making it unlikely that gene regulatory pathways which are essential for development are mutually exclusive from those necessary for regeneration. One such post-transcriptional gene regulatory pathway, which has been previously shown to be essential for functional metazoan development, is RNA editing. RNA editing catalyses discrete nucleotide changes in RNA transcripts, creating a molecular diversity that could create an enticing connection to the activated cellular plasticity found in newts during regeneration. To assess whether RNA editing occurs during regeneration, we demonstrated that GABRA3 and ADAR2 mRNA transcripts are edited in uninjured and regenerating tissues. Full open-reading frame sequences for ADAR1 and ADAR2, two enzymes responsible for adenosine-to-inosine RNA editing, were cloned from newt brain cDNA and exhibited a strong resemblance to ADAR (adenosine deaminase, RNA-specific) enzymes discovered in mammals. We demonstrated that ADAR1 and ADAR2 mRNA expression levels are differentially expressed during different phases of regeneration in multiple tissues, whereas protein expression levels remain unaltered. In addition, we have characterized a fascinating nucleocytoplasmic shuttling of ADAR1 in a variety of different cell types during regeneration, which could provide a mechanism for controlling RNA editing, without altering translational output of the editing enzyme. The link between RNA editing and regeneration provides further insights into how lower organisms, such as the newt, can activate essential molecular pathways via the discrete alteration of RNA sequences. PMID:23534823

  14. Histological changes, apoptosis and metallothionein levels in Triturus carnifex (Amphibia, Urodela) exposed to environmental cadmium concentrations.

    PubMed

    Capaldo, Anna; Gay, Flaminia; Scudiero, Rosaria; Trinchella, Francesca; Caputo, Ivana; Lepretti, Marilena; Marabotti, Anna; Esposito, Carla; Laforgia, Vincenza

    2016-04-01

    The aim of this study was to verify if the freshwater safety values established from the European Community (1998) and the Italian Ministry of Health (2001) for cadmium (44.5nM/L in drinking water and 178nM/L in sewage waters) were safe for amphibians, since at these same concentrations cadmium induced endocrine disruption in the newt Triturus carnifex. Adult male specimens of T. carnifex were exposed daily to cadmium (44.5nM/L and 178nM/L as CdCl2, nominal concentrations), respectively, during 3- and 9-months; at the same time, control newts were exposed to tap water only. The accumulation of cadmium in the skin, liver and kidney, the levels of metallothioneins in the skin and the liver, the expression of metallothionein mRNA in the liver, as well as the presence of histological alterations and of apoptosis in the target organs were evaluated. The 9-months exposure induced cadmium accumulation in all the tissues examined; moreover, histological changes were observed in all the tissues examined, irrespective of the dose or the time of exposure. Apoptosis was only detected in the kidney, whereas metallothioneins and metallothionein mRNA did not increase. This study demonstrates that the existing chronic water quality criterion established for cadmium induces in the newt T. carnifex cadmium accumulation and histological alterations in the target organs examined. Together with our previous results, showing that, at these same concentrations, cadmium induced endocrine disruption, the present results suggest that the existing chronic water quality criterion for cadmium appears to be not protective of amphibians.

  15. SCALE 5.1 Predictions of PWR Spent Nuclear Fuel Isotopic Compositions

    SciTech Connect

    Radulescu, Georgeta; Gauld, Ian C; Ilas, Germina

    2010-03-01

    The purpose of this calculation report is to document the comparison to measurement of the isotopic concentrations for pressurized water reactor (PWR) spent nuclear fuel determined with the Standardized Computer Analysis for Licensing Evaluation (SCALE) 5.1 (Ref. ) epletion calculation method. Specifically, the depletion computer code and the cross-section library being evaluated are the twodimensional (2-D) transport and depletion module, TRITON/NEWT,2, 3 and the 44GROUPNDF5 (Ref. 4) cross-section library, respectively, in the SCALE .1 code system.

  16. [Biologically Active Peptides Isolated from Dill Anethum graveolens L].

    PubMed

    Kulikova, O G; Maltsev, D I; Ilyina, A P; Burdina, A V; Yamskova, V P; Yamskov, I A

    2015-01-01

    Peptide mixtures with molecular weights of 1000-2000 Da and in vivo membrano-trophic activity against mouse hepatocyte culture at very low concentrations were isolated from dill Anethum graveolens L. leaves. It has been found that plant peptides in aqueous solution formed larger nanosized particles of approximately 90 nm with a secondary structure mainly composed of β-structures and random coil structures. We demonstrated that peptides isolated from A. graveolens in vitro at an ultra-low dosage affected the size of the area of pigmented cells of amphibian liver, which are analogous to Kupffer cells of the mammalian liver, using roller organotypic newt liver culture models. PMID:26204780

  17. Suppression of Odorant Responses by Odorants in Olfactory Receptor Cells

    NASA Astrophysics Data System (ADS)

    Kurahashi, Takashi; Lowe, Graeme; Gold, Geoffrey H.

    1994-07-01

    Odorants activate an inward current in vertebrate olfactory receptor cells. Here it is shown, in receptor cells from the newt, that odorants can also suppress this current, by a mechanism that is distinct from inhibition and adaptation. Suppression provides a simple explanation for two seemingly unrelated phenomena: the anomalously long latency of olfactory transduction and the existence of an "off response" at the end of a prolonged stimulus. Suppression may influence the perception of odorants by masking odorant responses and by sharpening the odorant specificities of single cells.

  18. Tail regeneration in Urodela: old model and new perspectives in studies

    NASA Astrophysics Data System (ADS)

    Grigoryan, E.; Anton, H.; Mitashov, V.

    For better understanding of micro-"g" effect on nervous tissue regeneration we have chosen the regeneration of the Urodele tail, because it utilizes many developmental processes and represents the most convenient model for experiments in Space. The special interesting aspect lies in the ability of regenerates to differentiate the spinal cord (SC) and this, in turn, has a potential of practical application. Meanwhile there are conclusive evidences suggesting the production by SC cells the neurotrophic factors promoting cell proliferation and differentiation in growing tail regenerate. Previously our studies on tail regeneration in the adult newt showed that the force of gravity clearly inf luences the events underlying the regeneration. We reported the significant increase of tail regeneration rate and tissue volume of tail regenerates in the newts exposed to real and simulated low "g". In Bion 11 mission animals that were exposed 14 days in microgravity and whose tails were operated two and four weeks before launch demonstrated the regenerates achieved 1.5 - 2 times the volume of those in 1"g" control. Results of this experiment indicated also that the regeneration of central and peripheral neurons and nerve fibers was carrying out faster under low "g" conditions than in 1 "g" control. Similar data were obtained in several experiments remodeling physiological weightlessness by mean of the clinostat. It led us to the hypothesis that the stimulation of tail regeneration is linked with an over activation of neurotrophic factors produced by quickly growing SC neurons. Now we've completed the experiment on tail regeneration in the newts Tr. alpestris subjected to 5 day long clinorotation after 6 days post tail amputation. The rate of primary- and secondary regeneration was evaluated at different time points after treatment. Cell proliferation, differentiation and expression of neurotrophic proteins in SC and other major tissue-type of regenerate were investigated by

  19. [Study of a new group of bioregulators isolated from the greater plantain (Plantago major L.)].

    PubMed

    Krasnov, M S; Iamskova, V P; Margasiuk, D V; Kulikova, O G; Il'ina, A P; Rybakova, E Iu; Iamslov, I A

    2011-01-01

    Proteins with physicochemical properties and biological activity similar to those of membrano-tropic homeostatic tissue-specific bioregulators that had been found earlier in various animal tissues were discovered in leaves of the common plantain (Plantago major L.). To study the specific activity of these plant proteins, we developed an experimental model for organotypic roller cultivation of newt (Pleurodeles waltl) skin tissue in vitro. We showed that the plant proteins of interest exert the wound-healing effect, which is characteristic of this plant, on the skin of vertebrates both in vitro and in vivo. PMID:22808737

  20. Could we also be regenerative superheroes, like salamanders?

    PubMed

    Dall'Agnese, Alessandra; Puri, Pier Lorenzo

    2016-09-01

    Development of methods to reawaken the semi-dormant regenerative potential that lies within adult human tissues would hold promise for the restoration of diseased or damaged organs and tissues. While most of the regeneration potential is suppressed in many vertebrates, including humans, during adult life, urodele amphibians (salamanders) retain their regenerative ability throughout adulthood. Studies in newts and axolotls, two salamander models, have provided significant knowledge about adult limb regeneration. In this review, we present a comparative analysis of salamander and mammalian regeneration and discuss how evolutionarily altered properties of the regenerative environment can be exploited to restore full regenerative potential in the human body. PMID:27338874

  1. Could we also be regenerative superheroes, like salamanders?

    PubMed

    Dall'Agnese, Alessandra; Puri, Pier Lorenzo

    2016-09-01

    Development of methods to reawaken the semi-dormant regenerative potential that lies within adult human tissues would hold promise for the restoration of diseased or damaged organs and tissues. While most of the regeneration potential is suppressed in many vertebrates, including humans, during adult life, urodele amphibians (salamanders) retain their regenerative ability throughout adulthood. Studies in newts and axolotls, two salamander models, have provided significant knowledge about adult limb regeneration. In this review, we present a comparative analysis of salamander and mammalian regeneration and discuss how evolutionarily altered properties of the regenerative environment can be exploited to restore full regenerative potential in the human body.

  2. STS-65 Mission Specialist Chiao in front of IML-2 Rack 3 aboard OV-102

    NASA Technical Reports Server (NTRS)

    1994-01-01

    STS-65 Mission Specialist Leroy Chiao is seen in the International Microgravity Laboratory 2 (IML-2) spacelab science module in front of Rack 3 and above center aisle equipment. Chiao has just made an observation of the goldfish container (silver apparatus on left between his right hand and knee). The Rack 3 Aquatic Animal Experiment Unit (AAEU) also contains Medaka and newts. Chiao joined five other NASA astronauts and a Japanese payload specialist for two weeks of experimenting onboard the Space Shuttle Columbia, Orbiter Vehicle (OV) 102, in Earth orbit.

  3. Cardiovascular physiology and diseases of amphibians.

    PubMed

    Heinz-Taheny, Kathleen M

    2009-01-01

    The class Amphibia includes three orders of amphibians: the anurans (frogs and toads), urodeles (salamanders, axolotls, and newts), and caecilians. The diversity of lifestyles across these three orders has accompanying differences in the cardiovascular anatomy and physiology allowing for adaptations to aquatic or terrestrial habitats, pulmonic or gill respiration, hibernation, and body elongation (in the caecilian). This article provides a review of amphibian cardiovascular anatomy and physiology with discussion of unique species adaptations. In addition, amphibians as cardiovascular animal models and commonly encountered natural diseases are covered.

  4. [Dynamics of the intensity of respiration in early embryogenesis of amphibians].

    PubMed

    Vladimirova, I G; Zlochevskaia, M B; Ozerniuk, N D

    2000-01-01

    We studied growth and respiration rate during early ontogenesis of the axolotl Ambystoma mexicanum, Bosca's newt Triturus waltlii, the green toad Bufo viridis, and the smooth clawed frog Xenopus laevis. The respiration rate in these amphibian species increases during embryonal and larval development, peaks after transition to active feeding, and decreases at later stages of ontogenesis. The patterns of dynamics of this energy metabolism index in tailed and tailless amphibians have some differences related to their specific development. The changes in respiration rate in the embryos and larvae are correlated with the concentrations of mitochondria. PMID:11036669

  5. Internet censorship: Congress moves toward final decision.

    PubMed

    Mirken, B

    1995-12-01

    The House and the Senate have passed proposals restricting the online access to obscene or indecent information. AIDS activists and service organizations fear that the proposals will restrict the distribution of HIV/AIDS information. A House/Senate conference committee soon will meet for a final decision. Religious right organizations are pressing for additional restrictions, while civil liberties, arts, and libertarian groups have expressed opposition on freedom-of-speech grounds. Some conservatives, including Newt Gingrich (R-GA), believe that the proposals may retard the growth of online communication.

  6. Cardiovascular physiology and diseases of amphibians.

    PubMed

    Heinz-Taheny, Kathleen M

    2009-01-01

    The class Amphibia includes three orders of amphibians: the anurans (frogs and toads), urodeles (salamanders, axolotls, and newts), and caecilians. The diversity of lifestyles across these three orders has accompanying differences in the cardiovascular anatomy and physiology allowing for adaptations to aquatic or terrestrial habitats, pulmonic or gill respiration, hibernation, and body elongation (in the caecilian). This article provides a review of amphibian cardiovascular anatomy and physiology with discussion of unique species adaptations. In addition, amphibians as cardiovascular animal models and commonly encountered natural diseases are covered. PMID:19131029

  7. The zebrafish as a model of heart regeneration.

    PubMed

    Raya, Angel; Consiglio, Antonella; Kawakami, Yasuhiko; Rodriguez-Esteban, Concepcion; Izpisúa-Belmonte, Juan Carlos

    2004-01-01

    Regeneration is a complex biological process by which animals can restore the shape, structure and function of body parts lost after injury, or after experimental amputation. Only a few species of vertebrates display the capacity to regenerate body parts during adulthood. In the case of the heart, newts display a remarkable ability to regenerate large portions of myocardium after amputation, although the mechanisms underlying this process have not been addressed. Recently, it has been shown that adult zebrafish can also regenerate their hearts, thus offering new possibilities for experimentally approaching this fascinating biological phenomenon. The first insights into heart regeneration gained by studying this model organism are reviewed here. PMID:15671662

  8. [Study of a new group of bioregulators isolated from the greater plantain (Plantago major L.)].

    PubMed

    Krasnov, M S; Iamskova, V P; Margasiuk, D V; Kulikova, O G; Il'ina, A P; Rybakova, E Iu; Iamslov, I A

    2011-01-01

    Proteins with physicochemical properties and biological activity similar to those of membrano-tropic homeostatic tissue-specific bioregulators that had been found earlier in various animal tissues were discovered in leaves of the common plantain (Plantago major L.). To study the specific activity of these plant proteins, we developed an experimental model for organotypic roller cultivation of newt (Pleurodeles waltl) skin tissue in vitro. We showed that the plant proteins of interest exert the wound-healing effect, which is characteristic of this plant, on the skin of vertebrates both in vitro and in vivo.

  9. Identification of lactic acid bacteria involved in the spoilage of pasteurized "foie gras" products.

    PubMed

    Matamoros, S; André, S; Hue, I; Prévost, H; Pilet, M F

    2010-07-01

    The spoiling microflora of a re-packaged French "foie gras" product was studied. A total of 54 isolates, originating from two different factories, were identified using phenotypical and molecular methods (partial 16S rDNA sequencing). Weissella viridescens was the main species detected in the products from factory 1 (64% of the isolates). These products had a low lactic acid concentration and were considered as non-spoiled. The microflora of factory 2 was dominated mainly by the genus Lactobacillus (95% of the isolates), and the high lactic acid concentration of these products was linked with a strong spoilage. Among the 30 Lactobacillus strains, three species were predominant: Lactobacillus sakei (nine isolates), Lactobacillus coryniformis (eight isolates) and Lactobacillus paraplantarum (five isolates). Challenge tests were performed to confirm the involvement of the Lactobacillus strains in the spoilage of the product. Sterile "foie gras" samples were inoculated with 14 LAB strains from the collection. The most acidifying strains belonged to the species L. sakei, Lactobacillus plantarum and L. paraplantarum. This confirmed the role of the strains from the Lactobacillus genus as the main spoilers of "foie gras" products and will be useful to design new quality protocols and extend the shelf-life of these products.

  10. Identification and significance of Weissella species infections

    PubMed Central

    Kamboj, Kamal; Vasquez, Amber; Balada-Llasat, Joan-Miquel

    2015-01-01

    Weissella spp. are non-spore forming, catalase-negative, gram-positive coccobacilli. They are often misidentified by traditional and commercial phenotypic identification methods as Lactobacillus spp. or Lactobacillus-like organisms. Weissella spp. were previously grouped along with Lactobacillus spp., Leuconostoc spp., and Pediococcus spp. Utilization of more sensitive methods like DNA sequencing or Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) has facilitated identification of Weissella as a unique genus. Nineteen species have been identified to date. W. confusa, W. cibaria, and W. viridescens are the only species isolated from humans. The true prevalence of Weissella spp. continues to be probably underestimated. Weissella spp. strains have been isolated from a wide range of habitats including raw milk, feces, fermented cereals, and vegetables. Weisella is believed to be a rare cause of usually nonfatal infections in humans, and is often considered a contaminant. However, in recent years, Weissella spp. have been implicated in bacteremia, abscesses, prosthetic joint infections, and infective endocarditis. Alterations of the gut flora from surgery or chemotherapy are believed to facilitate translocation of Weissella spp. due to disruption of the mucosal barrier, predisposing the host to infection with this organism. Implications of the isolation of Weissella spp. from blood must be interpreted in context of underlying risk factors. Weissella spp. are inherently resistant to vancomycin. Therefore, early consideraton of the pathogenic role of this bacteria and choice of alternate therapy is important to assure better outcomes. PMID:26583007

  11. New teleomorph combinations in the entomopathogenic genus Metacordyceps.

    PubMed

    Kepler, R M; Sung, G-H; Ban, S; Nakagiri, A; Chen, M-J; Huang, B; Li, Z; Spatafora, J W

    2012-01-01

    The genus Metacordyceps contains arthropod pathogens in Clavicipitaceae (Hypocreales) that formerly were classified in Cordyceps sensu Kobayasi et Mains. Of the current arthropod pathogenic genera of Hypocreales, the genus Metacordyceps remains one of the most poorly understood and contains a number of teleomorphic morphologies convergent with species of Cordyceps s.s. (Cordycipitaceae) and Ophiocordyceps (Ophiocordycipitaceae). Of note, the anamorph genera Metarhizium and Pochonia were found to be associated only with Metacordyceps and demonstrated to be phylogenetically informative for the clade. Several species of Cordyceps considered to have uncertain placements (incertae sedis) in the current taxonomic framework of clavicipitoid fungi were collected during field expeditions mostly in eastern Asia. Species reclassified here in Metacordyceps include Cordyceps atrovirens Kobayasi & Shimizu, Cordyceps indigotica Kobayasi & Shimizu, Cordyceps khaoyaiensis Hywel-Jones, Cordyceps kusanagiensis Kobayasi & Shimizu, Cordyceps martialis Speg., Ophiocordyceps owariensis Kobayasi, Cordyceps pseudoatrovirens Kobayasi & Shimizu and Ophicordyceps owariensis f. viridescens (Uchiy. & Udagawa) G.H. Sung, J.M. Sung, Hywel-Jones & Spatafora. Incorporation of these species in a multigene phylogenetic framework of the major clades of clavicipitoid fungi more than doubled the number of species in Metacordyceps and allowed for refinement of morphological concepts for the genus consistent with the phylogenetic structure. Based on these findings we then discuss evolution of this genus, subgeneric relationships, anamorph connections, and suggest additional species that should be confirmed for possible inclusion in Metacordyceps. PMID:22067304

  12. Trichoderma species occurring on wood with decay symptoms in mountain forests in Central Europe: genetic and enzymatic characterization.

    PubMed

    Błaszczyk, Lidia; Strakowska, Judyta; Chełkowski, Jerzy; Gąbka-Buszek, Agnieszka; Kaczmarek, Joanna

    2016-08-01

    The aim of this study was to explore the species diversity of Trichoderma obtained from samples of wood collected in the forests of the Gorce Mountains (location A), Karkonosze Mountains (location B) and Tatra Mountains (location C) in Central Europe and to examine the cellulolytic and xylanolytic activity of these species as an expression of their probable role in wood decay processes. The present study has led to the identification of the following species and species complex: Trichoderma atroviride P. Karst., Trichoderma citrinoviride Bissett, Trichoderma cremeum P. Chaverri & Samuels, Trichoderma gamsii Samuels & Druzhin., Trichoderma harzianum complex, Trichoderma koningii Oudem., Trichoderma koningiopsis Samuels, C. Suárez & H.C. Evans, Trichoderma longibrachiatum Rifai, Trichoderma longipile Bissett, Trichoderma sp. (Hypocrea parapilulifera B.S. Lu, Druzhin. & Samuels), Trichoderma viride Schumach. and Trichoderma viridescens complex. Among them, T. viride was observed as the most abundant species (53 % of all isolates) in all the investigated locations. The Shannon's biodiversity index (H), evenness (E), and the Simpson's biodiversity index (D) calculations for each location showed that the highest species diversity and evenness were recorded for location A-Gorce Mountains (H' = 1.71, E = 0.82, D = 0.79). The preliminary screening of 119 Trichoderma strains for cellulolytic and xylanolytic activity showed the real potential of all Trichoderma species originating from wood with decay symptoms to produce cellulases and xylanases-the key enzymes in plant cell wall degradation. PMID:26586561

  13. A revision of the Deltochilum subgenus Aganhyboma Kolbe, 1893 (Coleoptera: Scarabaeidae: Scarabaeinae).

    PubMed

    Silva, Fernando A B; Louzada, Júlio; Vaz-de-Mello, Fernando

    2015-01-01

    The species of the Deltochilum subgenus Aganhyboma, endemic to Central and South America, are reviewed. The species have been divided into complexes, with a brief diagnosis presented for each. A key for identification of 26 currently recognized species is provided in English and Portuguese. Two major groups within the subgenus are recognized (trisignatum and valgum). The first is represented by species typically belonging to the subgenus Aganhyboma (Deltochilum (A.) trisignatum, D. (A.) kolbei, D. (A.) violaceum, D. (A.) cupreicolle and D. (A.) viridescens new status) and three new species described here (D. (A.) amandaarcanjoae, D. (A.) viridicatum and D. (A.) titovidaurrei). The second group (valgum) is represented by: D. (A.) valgum, D. (A.) longiceps new status, D. (A.) acropyge new status, D. (A.) acanthus, D. (A.) icaroides and D. (A.) icariforme), previously assigned to the subgenus Deltohyboma. Twelve new species are described for the valgum group (D. (A.) schefflerorum; D. (A.) streblopodum; D. (A.) feeri; D. (A.) larseni; D. (A.) arturoi; D. (A.) finestriatum; D. (A.) cangalha; D. (A.) alpercata; D. (A.) ritamourae; D. (A.) kolleri; D. (A.) paresi; D. (A.) subrubrum). A lectotype is designated for D. (A.) trisignatum and D. (A.) icariforme. A detailed literature review, synonymies, description, illustration of key morphological characters, data of the studied material and geographic distribution is provided for each species.

  14. Fungal endophytic communities on twigs of fast and slow growing Scots pine (Pinus sylvestris L.) in northern Spain.

    PubMed

    Sanz-Ros, Antonio V; Müller, Michael M; San Martín, Roberto; Diez, Julio J

    2015-10-01

    Most plant species harbour a diverse community of endophytic, but their role is still unknown in most cases, including ecologically and economically important tree species. This study describes the culturable fungal endophytic community of Pinus sylvestris L. twigs in northern Spain and its relationship with diametric growth of the host. In all, 360 twig samples were collected from 30 Scots pines in fifteen stands. Isolates were obtained from all twig samples and 43 fungal taxa were identified by morphogrouping and subsequent ITS rDNA sequencing. All isolates were Ascomycetes, being Dothideomycetes and Sordariomycetes the most abundant classes. Half of the species were host generalists while the others were conifer or pine specialists. We found three new endophytic species for the Pinaceae: Biscogniauxia mediterranea, Phaeomoniella effusa and Plectania milleri, and additional six new species for P. sylvestris: Daldinia fissa, Hypocrea viridescens, Nigrospora oryzae, Ophiostoma nigrocarpum, Penicillium melinii and Penicillium polonicum. The endophytic community of fast and slow growing trees showed differences in species composition, abundance and evenness, but not in diversity. Phoma herbarum was associated to fast growing trees and Hypocrea lixii to those growing slow. Our results support the hypothesis that some endophytic species may affect growth of P. sylvestris.

  15. Interactive inhibition of meat spoilage and pathogenic bacteria by lysozyme, nisin and EDTA in the presence of nitrite and sodium chloride at 24 degrees C.

    PubMed

    Gill, Alexander O; Holley, Richard A

    2003-02-15

    To develop a nisin- and lysozyme-based antimicrobial treatment for use with processed ham and bologna, in vitro experiments were conducted to determine whether inhibition enhancing interactions occur between the antimicrobials lysozyme, chrisin (a commercial nisin preparation), EDTA, NaCl and NaNO(2). Inhibitory interactions were observed between a number of agents when used against specific pathogenic and spoilage bacteria. The observed interactions included lysozyme with EDTA (Enterococcus faecalis and Weissella viridescens), chrisin with EDTA (all Gram-positive organisms), EDTA with NaCl (Escherichia coli, Salmonella enterica serovar Typhimurium, Serratia grimesii), EDTA with nitrite (E. coli, Lactobacillus curvatus, Leuconostoc mesenteroides, Listeria monocytogenes, S. Typhimurium), chrisin with nitrite (Lc. mesenteroides, L. monocytogenes), and NaCl with nitrite (S. Typhimurium, Shewanella putrefaciens). Previous reports have described interactions between nisin with EDTA that resulted in enhanced antimicrobial effect against Gram-negative bacteria, or lysozyme with nisin against Gram-positive bacteria. These interactions were not observed in these experiments. We observed that unlike previous studies, these experiments were conducted on growing cells in nutrient broth, rather than under conditions of nutrient limitation. We propose that screening of antimicrobials for use in food systems in nutrient-deficient systems is inappropriate and that new protocols should be developed. PMID:12423927

  16. Thiamin requirement of the adult human.

    PubMed

    Sauberlich, H E; Herman, Y F; Stevens, C O; Herman, R H

    1979-11-01

    Young adult male subjects maintained on a metabolic ward were fed diets providing controlled intakes of thiamin and either 2800 or 3600 kcal. The higher level of calories was attained by an increased intake of carbohydrates. Constant weights were maintained by the subjects by adjusting daily activity and exercise schedules. Thiamin requirements were evaluated in terms of erythrocyte transketolase activity and urinary excretion of the vitamin. The results of the study revealed that a relationship exists between thiamin requirement and caloric intake and expenditure. Thus, when the calories being utilized were derived primarily from carbohydrate sources, the minimum adult male requirement for thiamin appeared to be 0.30 mg of thiamin per 1000 kcal. Urinary excretion of thiamin and erythrocyte transketolase activity appear to be reasonably reliable reflections of thiamin intakes and thiamin nutritional status. The use of these measurements in nutrition surveys appears justified. The microbiological assay (Lactobacillus viridescens) for measuring thiamin levels in urine samples appears to be a somewhat more sensitive but valid procedure as an alternate for the thiochrome method. Judged from the results of this study, the recommended intake for the adult human of 0.40 mg of thiamin per 1000 kcal by FAO/WHO and the recommended allowance of 0.5 mg per 1000 kcal by the Food and Nutrition Board of the NAS-NRC appear reasonable and amply allow for biological variations and other factors that may influence the requirement for this vitamin.

  17. Genetic and metabolic biodiversity of Trichoderma from Colombia and adjacent neotropic regions.

    PubMed

    Hoyos-Carvajal, Lilliana; Orduz, Sergio; Bissett, John

    2009-09-01

    The genus Trichoderma has been studied for production of enzymes and other metabolites, as well as for exploitation as effective biological control agents. The biodiversity of Trichoderma has seen relatively limited study over much of the neotropical region. In the current study we assess the biodiversity of 183 isolates from Mexico, Guatemala, Panama, Ecuador, Peru, Brazil and Colombia, using morphological, metabolic and genetic approaches. A comparatively high diversity of species was found, comprising 29 taxa: Trichoderma asperellum (60 isolates), Trichoderma atroviride (3), Trichoderma brevicompactum (5), Trichoderma crassum (3), Trichoderma erinaceum (3), Trichoderma gamsii (2), Trichoderma hamatum (2), Trichoderma harzianum (49), Trichoderma koningiopsis (6), Trichoderma longibrachiatum (3), Trichoderma ovalisporum (1), Trichoderma pubescens (2), Trichoderma rossicum (4), Trichoderma spirale (1), Trichoderma tomentosum (3), Trichoderma virens (8), Trichoderma viridescens (7) and Hypocrea jecorina (3) (anamorph: Trichoderma reesei), along with 11 currently undescribed species. T. asperellum was the prevalent species and was represented by two distinct genotypes with different metabolic profiles and habitat preferences. The second predominant species, T. harzianum, was represented by three distinct genotypes. The addition of 11 currently undescribed species is evidence of the considerable unresolved biodiversity of Trichoderma in neotropical regions. Sequencing of the internal transcribed spacer regions (ITS) of the ribosomal repeat could not differentiate some species, and taken alone gave several misidentifications in part due to the presence of nonorthologous copies of the ITS in some isolates.

  18. Blue pigment in Hypocrea caerulescens sp. nov. and two additional new species in sect. Trichoderma

    PubMed Central

    Jaklitsch, Walter M.; Stadler, Marc; Voglmayr, Hermann

    2012-01-01

    Three new species of Hypocrea/Trichoderma sect. Trichoderma (Hypocreaceae, Hypocreales, Ascomycota, Fungi) are described from recent collections in southern Europe and the Canary Islands. They have been characterized by morphological and molecular methods, including microscopic examination of the teleomorph in thin sections, the anamorph, growth rate experiments and phylogenetic analyses based on a part of the translation elongation factor 1-alpha encoding gene (tef1) containing the two last introns and a part of the rpb2 gene, encoding the second largest RNA polymerase subunit. Analyses involving tef1 did not unequivocally resolve the sister clade relationship of Hypocrea caerulescens relative to the Koningii and Viride clades, while analyses based on rpb2 clearly suggest a close relationship with the former, although the phenotype of H. caerulescens is similar to H. viridescens, particularly by its warted conidia and a coconut-like odor in CMD culture. Hypocrea hispanica and T. samuelsii however are clearly related to the Viride clade by both phylogenetic markers, despite their morphological similarity to H. koningii and its relatives. An apparently specific blue pigment is formed in CMD cultures by Hypocrea caerulescens but could not be obtained by extraction with organic solvents. PMID:22453122

  19. Application of local gene induction by infrared laser-mediated microscope and temperature stimulator to amphibian regeneration study.

    PubMed

    Kawasumi-Kita, Aiko; Hayashi, Toshinori; Kobayashi, Takuya; Nagayama, Chikashi; Hayashi, Shinichi; Kamei, Yasuhiro; Morishita, Yoshihiro; Takeuchi, Takashi; Tamura, Koji; Yokoyama, Hitoshi

    2015-12-01

    Urodele amphibians (newts and salamanders) and anuran amphibians (frogs) are excellent research models to reveal mechanisms of three-dimensional organ regeneration since they have exceptionally high regenerative capacity among tetrapods. However, the difficulty in manipulating gene expression in cells in a spatially restricted manner has so far hindered elucidation of the molecular mechanisms of organ regeneration in amphibians. Recently, local heat shock by laser irradiation has enabled local gene induction even at the single-cell level in teleost fishes, nematodes, fruit flies and plants. In this study, local heat shock was made with infrared laser irradiation (IR-LEGO) by using a gene expression inducible system in transgenic animals containing a heat shock promoter, and gene expression was successfully induced only in the target region of two amphibian species, Xenopus laevis and Pleurodeles waltl (a newt), at postembryonic stages. Furthermore, we induced spatially restricted but wider gene expression in Xenopus laevis tadpoles and froglets by applying local heat shock by a temperature-controlled metal probe (temperature stimulator). The local gene manipulation systems, the IR-LEGO and the temperature stimulator, enable us to do a rigorous cell lineage trace with the combination of the Cre-LoxP system as well as to analyze gene function in a target region or cells with less off-target effects in the study of amphibian regeneration.

  20. Elasticity and structure of eukaryote chromosomes studied by micromanipulation and micropipette aspiration.

    PubMed

    Houchmandzadeh, B; Marko, J F; Chatenay, D; Libchaber, A

    1997-10-01

    The structure of mitotic chromosomes in cultured newt lung cells was investigated by a quantitative study of their deformability, using micropipettes. Metaphase chromosomes are highly extensible objects that return to their native shape after being stretched up to 10 times their normal length. Larger deformations of 10 to 100 times irreversibly and progressively transform the chromosomes into a "thin filament," parts of which display a helical organization. Chromosomes break for elongations of the order of 100 times, at which time the applied force is around 100 nanonewtons. We have also observed that as mitosis proceeds from nuclear envelope breakdown to metaphase, the native chromosomes progressively become more flexible. (The elastic Young modulus drops from 5,000 +/- 1,000 to 1,000 +/- 200 Pa.) These observations and measurements are in agreement with a helix-hierarchy model of chromosome structure. Knowing the Young modulus allows us to estimate that the force exerted by the spindle on a newt chromosome at anaphase is roughly one nanonewton.

  1. Cardiomyocyte proliferation in cardiac development and regeneration: a guide to methodologies and interpretations.

    PubMed

    Leone, Marina; Magadum, Ajit; Engel, Felix B

    2015-10-01

    The newt and the zebrafish have the ability to regenerate many of their tissues and organs including the heart. Thus, a major goal in experimental medicine is to elucidate the molecular mechanisms underlying the regenerative capacity of these species. A wide variety of experiments have demonstrated that naturally occurring heart regeneration relies on cardiomyocyte proliferation. Thus, major efforts have been invested to induce proliferation of mammalian cardiomyocytes in order to improve cardiac function after injury or to protect the heart from further functional deterioration. In this review, we describe and analyze methods currently used to evaluate cardiomyocyte proliferation. In addition, we summarize the literature on naturally occurring heart regeneration. Our analysis highlights that newt and zebrafish heart regeneration relies on factors that are also utilized in cardiomyocyte proliferation during mammalian fetal development. Most of these factors have, however, failed to induce adult mammalian cardiomyocyte proliferation. Finally, our analysis of mammalian neonatal heart regeneration indicates experiments that could resolve conflicting results in the literature, such as binucleation assays and clonal analysis. Collectively, cardiac regeneration based on cardiomyocyte proliferation is a promising approach for improving adult human cardiac function after injury, but it is important to elucidate the mechanisms arresting mammalian cardiomyocyte proliferation after birth and to utilize better assays to determine formation of new muscle mass.

  2. Cardiomyocyte proliferation in cardiac development and regeneration: a guide to methodologies and interpretations.

    PubMed

    Leone, Marina; Magadum, Ajit; Engel, Felix B

    2015-10-01

    The newt and the zebrafish have the ability to regenerate many of their tissues and organs including the heart. Thus, a major goal in experimental medicine is to elucidate the molecular mechanisms underlying the regenerative capacity of these species. A wide variety of experiments have demonstrated that naturally occurring heart regeneration relies on cardiomyocyte proliferation. Thus, major efforts have been invested to induce proliferation of mammalian cardiomyocytes in order to improve cardiac function after injury or to protect the heart from further functional deterioration. In this review, we describe and analyze methods currently used to evaluate cardiomyocyte proliferation. In addition, we summarize the literature on naturally occurring heart regeneration. Our analysis highlights that newt and zebrafish heart regeneration relies on factors that are also utilized in cardiomyocyte proliferation during mammalian fetal development. Most of these factors have, however, failed to induce adult mammalian cardiomyocyte proliferation. Finally, our analysis of mammalian neonatal heart regeneration indicates experiments that could resolve conflicting results in the literature, such as binucleation assays and clonal analysis. Collectively, cardiac regeneration based on cardiomyocyte proliferation is a promising approach for improving adult human cardiac function after injury, but it is important to elucidate the mechanisms arresting mammalian cardiomyocyte proliferation after birth and to utilize better assays to determine formation of new muscle mass. PMID:26342071

  3. Application of local gene induction by infrared laser-mediated microscope and temperature stimulator to amphibian regeneration study.

    PubMed

    Kawasumi-Kita, Aiko; Hayashi, Toshinori; Kobayashi, Takuya; Nagayama, Chikashi; Hayashi, Shinichi; Kamei, Yasuhiro; Morishita, Yoshihiro; Takeuchi, Takashi; Tamura, Koji; Yokoyama, Hitoshi

    2015-12-01

    Urodele amphibians (newts and salamanders) and anuran amphibians (frogs) are excellent research models to reveal mechanisms of three-dimensional organ regeneration since they have exceptionally high regenerative capacity among tetrapods. However, the difficulty in manipulating gene expression in cells in a spatially restricted manner has so far hindered elucidation of the molecular mechanisms of organ regeneration in amphibians. Recently, local heat shock by laser irradiation has enabled local gene induction even at the single-cell level in teleost fishes, nematodes, fruit flies and plants. In this study, local heat shock was made with infrared laser irradiation (IR-LEGO) by using a gene expression inducible system in transgenic animals containing a heat shock promoter, and gene expression was successfully induced only in the target region of two amphibian species, Xenopus laevis and Pleurodeles waltl (a newt), at postembryonic stages. Furthermore, we induced spatially restricted but wider gene expression in Xenopus laevis tadpoles and froglets by applying local heat shock by a temperature-controlled metal probe (temperature stimulator). The local gene manipulation systems, the IR-LEGO and the temperature stimulator, enable us to do a rigorous cell lineage trace with the combination of the Cre-LoxP system as well as to analyze gene function in a target region or cells with less off-target effects in the study of amphibian regeneration. PMID:26510480

  4. Contributions to the functional morphology of caudate skulls: kinetic and akinetic forms

    PubMed Central

    Handschuh, Stephan; Lukanov, Simeon; Naumov, Borislav

    2016-01-01

    A strongly ossified and rigid skull roof, which prevents parietal kinesis, has been reported for the adults of all amphibian clades. Our μ-CT investigations revealed that the Buresch’s newt (Triturus ivanbureschi) possess a peculiar cranial construction. In addition to the typical amphibian pleurokinetic articulation between skull roof and palatoquadrate associated structures, we found flexible connections between nasals and frontals (prokinesis), vomer and parasphenoid (palatokinesis), and between frontals and parietals (mesokinesis). This is the first description of mesokinesis in urodelans. The construction of the skull in the Buresch’s newts also indicates the presence of an articulation between parietals and the exocipitals, discussed as a possible kind of metakinesis. The specific combination of pleuro-, pro-, meso-, palato-, and metakinetic skull articulations indicate to a new kind of kinetic systems unknown for urodelans to this date. We discuss the possible neotenic origin of the skull kinesis and pose the hypothesis that the kinesis in T. ivanbureschi increases the efficiency of fast jaw closure. For that, we compared the construction of the skull in T. ivanbureschi to the akinetic skull of the Common fire salamander Salamandra salamandra. We hypothesize that the design of the skull in the purely terrestrial living salamander shows a similar degree of intracranial mobility. However, this mobility is permitted by elasticity of some bones and not by true articulation between them. We comment on the possible relation between the skull construction and the form of prey shaking mechanism that the species apply to immobilize their victims. PMID:27688958

  5. The ontogenetic origins of skull shape disparity in the Triturus cristatus group.

    PubMed

    Cvijanović, Milena; Ivanović, Ana; Kalezić, Miloš L; Zelditch, Miriam L

    2014-09-01

    Comparative studies of ontogenies of closely related species provide insights into the mechanisms responsible for morphological diversification. Using geometric morphometrics, we investigated the ontogenetic dynamics of postlarval skull shape and disparity in three closely related crested newt species. The skull shapes of juveniles just after metamorphosis (hereafter metamorphs) and adult individuals were sampled by landmark configurations that describe the shape of the dorsal and ventral side of the newt skull, and analyzed separately. The three species differ in skull size and shape in metamorphs and adults. The ontogenies of dorsal and ventral skull differ in the orientation but not lengths of the ontogenetic trajectories. The disparity of dorsal skull shape increases over ontogeny, but that of ventral skull shape does not. Thus, modifications of ontogenetic trajectories can, but need not, increase the disparity of shape. In species with biphasic life-cycles, when ontogenetic trajectories for one stage can be decoupled from those of another, increases and decreases in disparity are feasible, but our results show that they need not occur.

  6. Experiment aboard Russian satellite "Foton M2" in 2005: new approaches for study on stimulating effect of space flight on cell proliferation and regeneration in Urodela

    NASA Astrophysics Data System (ADS)

    Grigoryan, E.; Almeida, E.; Domaratskaya, E.; Tairbekov, M.; Aleinikova, K.; Mitashov, V.

    A study on space flight effect upon processes of regeneration is due to the necessity to know their characteristics in animals and human exposed to space and earth conditions shortly after flight Several experiments on the newts performed earlier aboard Russian biosatellites showed that the rate of organ and tissue regeneration in space was greater than that on the ground Space flight effect stimulating regeneration was enduring and apparent not only just after flight but long time later as well This observation found support in studies simulated physiological weightlessness by means of fast-rotating clinostat It was shown also that the higher rate of regeneration was associated with enhanced cell proliferation For instance we found that the number of cells in S-phase in regenerating tissues was significantly greater in space-flown animals than in the ground controls However it was unclear whether cell proliferation stimulation was induced by micro- g per se or by conditions of hyper- g during launching and re-adaptation on the earth Molecular mechanisms underlying the change also remained obscure These issues were addressed by the joint Russian-USA experiment Regeneration performed on Foton-M2 in 2005 In 16- day flight we used two well-known models of regeneration lens regeneration after lensectomy and tail regeneration after amputation in adult newts Pleurodeles walt Urodela In order to evaluate cell proliferative activity in time limits of microgravity influence the original method for in-flight delivering DNA precursor BrdU

  7. High gene flow between alternative morphs and the evolutionary persistence of facultative paedomorphosis

    PubMed Central

    Oromi, Neus; Michaux, Johan; Denoël, Mathieu

    2016-01-01

    Paedomorphosis and metamorphosis are two major developmental processes that characterize the evolution of complex life cycles in many lineages. Whereas these processes were fixed in some taxa, they remained facultative in others, with alternative phenotypes expressed in the same populations. From a genetic perspective, it is still unknown whether such phenotypes form a single population or whether they show some patterns of isolation in syntopy. This has deep implications for understanding the evolution of the phenotypes, i.e. towards their persistence or their fixation and speciation. Newts and salamanders are excellent models to test this hypothesis because they exhibit both developmental processes in their populations: the aquatic paedomorphs retain gills, whereas the metamorphs are able to colonize land. Using microsatellite data of coexisting paedomorphic and metamorphic palmate newts (Lissotriton helveticus), we found that they formed a panmictic population, which evidences sexual compatibility between the two phenotypes. The high gene flow could be understood as an adaptation to unstable habitats in which phenotypic plasticity is favored over the fixation of developmental alternatives. This makes then possible the persistence of a polyphenism: only metamorphosis could be maintained in case of occasional drying whereas paedomorphosis could offer specific advantages in organisms remaining in water. PMID:27534370

  8. Functional joint regeneration is achieved using reintegration mechanism in Xenopus laevis.

    PubMed

    Tsutsumi, Rio; Yamada, Shigehito; Agata, Kiyokazu

    2016-02-01

    A functional joint requires integration of multiple tissues: the apposing skeletal elements should form an interlocking structure, and muscles should insert into skeletal tissues via tendons across the joint. Whereas newts can regenerate functional joints after amputation, Xenopus laevis regenerates a cartilaginous rod without joints, a "spike." Previously we reported that the reintegration mechanism between the remaining and regenerated tissues has a significant effect on regenerating joint morphogenesis during elbow joint regeneration in newt. Based on this insight into the importance of reintegration, we amputated frogs' limbs at the elbow joint and found that frogs could regenerate a functional elbow joint between the remaining tissues and regenerated spike. During regeneration, the regenerating cartilage was partially connected to the remaining articular cartilage to reform the interlocking structure of the elbow joint at the proximal end of the spike. Furthermore, the muscles of the remaining part inserted into the regenerated spike cartilage via tendons. This study might open up an avenue for analyzing molecular and cellular mechanisms of joint regeneration using Xenopus.

  9. An advanced deterministic method for spent-fuel criticality safety analysis

    SciTech Connect

    DeHart, M.D.

    1998-09-01

    Over the past two decades, criticality safety analysts have come to rely to a large extent on Monte Carlo methods for criticality calculations. Monte Carlo has become popular because of its capability to model complex, nonorthogonal configurations or fissile materials, typical of real-world problems. In the last few years, however, interest in determinist transport methods has been revived, due to shortcomings in the stochastic nature of Monte Carlo approaches for certain types of analyses. Specifically, deterministic methods are superior to stochastic methods for calculations requiring accurate neutron density distributions or differential fluxes. Although Monte Carlo methods are well suited for eigenvalue calculations, they lack the localized detail necessary to assess uncertainties and sensitivities important in determining a range of applicability. Monte Carlo methods are also inefficient as a transport solution for multiple-pin depletion methods. Discrete ordinates methods have long been recognized as one of the most rigorous and accurate approximations used to solve the transport equation. However, until recently, geometric constrains in finite differencing schemes have made discrete ordinates methods impractical for nonorthogonal configurations such as reactor fuel assemblies. The development of an extended step characteristic (ESC) technique removes the grid structure limitation of traditional discrete ordinates methods. The NEWT computer code, a discrete ordinates code built on the ESC formalism, is being developed as part of the SCALE code system. This paper demonstrates the power, versatility, and applicability of NEWT as a state-of-the-art solution for current computational needs.

  10. A deterministic study of deficiencies in the Wigner-Seitz cell approximation

    SciTech Connect

    DeHart, M.D.

    1999-09-01

    Monte Carlo methods are extremely powerful and heavily utilized for many applications in nuclear criticality safety. Accurate criticality calculations are possible because of the global nature of neutron multiplication. The stochastic approach has limitations, however, and is not appropriate for specialized applications that require differential fluxes or accurate neutron density distributions. The NEW Transport Algorithm (NEWT) computer code, developed at Oak Ridge National Laboratory (ORNL), has the ability to closely model nonorthogonal two-dimensional geometries that are traditionally left to Monte Carlo analyses. Because it is based on the discrete ordinates formalism, it can provide an accurate prediction of neutron distributions in space and energy. However, unlike most discrete ordinates methods, NEWT solves fluxes on a grid of arbitrary polygons, which can be used to closely approximate complex configurations. Results of multidimensional depletion and sensitivity/uncertainty analyses will be reported in the future after significant testing has been completed. Herein the authors focus on a recent study performed at ORNL to understand discrepancies noted for the Wigner-Seitz cell approximation often applied in lattice calculations.

  11. Experiment "Regeneration" Performed Aboard the Russian Spacecraft Foton-M2 in 2005

    NASA Technical Reports Server (NTRS)

    Grigoryan, Elonora; Almeida, Eduardo; Domaratskaya, Elena; Poplinskaya, Valentina; Aleinikova, Karina; Tairbekov, Murad; Mitashov, Victor

    2006-01-01

    The experiments on the newts performed earlier aboard Russian biosate llites showed that the rate of lens and tail regeneration in space wa s greater than on the ground. In parallel it was found that the numbe r of cells in S-phase was greater in space-flown animals than in the ground controls. However, it was unclear whether cell proliferation stimulation was induced by micro-g per se. Molecular mechanisms under lying the change also remained obscure. These issues were addressed b y the joint Russian-American experiment "Regeneration" flown on Foton -M2 in 2005. The method for in-flight delivering DNA precursor BrdU was developed. The experiment showed that during the flight the numbe r of S-phase cells in the regenerating eyes and tails increased. Thes e data together with those obtained earlier suggest that cell prolife ration increases in response to the effects of both micro-g and 1-g a fter return to Earth. The expression of bFGF in regenerating tissues of "flown" newts and ground controls was examined using immuno-histo chemistry. Obtained results suggest that this growth factor is a part icipant of the promotional effect of space flight upon cell prolifera tion in lens and tail regenerates.

  12. Total DNA transcription in vitro: a procedure to detect highly repetitive and transcribable sequences with tRNA-like structures

    SciTech Connect

    Endoh, H.; Okada, N.

    1986-01-01

    Total DNAs from various animals were transcribed in vitro in a HeLa cell extract, and it was found that one to several discrete RNAs were transcribed by RNA polymerase III. With tortoise (Geoclemys reevessi) and newt (Cynops pyrrhogaster), distinct 6.5S and 8S RNAs were transcribed from these respective DNAs. Representative phage clones carrying the 6.5S and 8S RNA genes were isolated from genomic libraries of these animals, and the sequences of these genes were determined. The 5' parts of highly repetitive and transcribable sequences of tortoise and newt were found to have close resemblance to tRNA/sub 1//sup Lys/ (rabbit) gene (78% homology) and a tRNA/sup Glu/ (Drosophila) gene (74% homology, not counting the aminoacyl stem region), respectively. The homologies extended to secondary structures, homologous nucleotides being located on similar secondary structures. It is proposed that many, if not all, highly repetitive and transcribable sequences detected by total DNA transcription have specific tRNA genes as their progenitors.

  13. Zooplankton Successions in Neighboring Lakes with Contrasting Impacts of Amphibian and Fish Predators

    NASA Astrophysics Data System (ADS)

    Schabetsberger, Robert; Grill, Susanne; Hauser, Gabriele; Wukits, Petra

    2006-06-01

    Two pairs of neighboring subalpine lakes located in the Northern Calcareous Alps of Austria were investigated. Each pair comprised a deeper lake containing European minnows (Phoxinus phoxinus ), and a corresponding shallower lake harboring Alpine newts (Triturus alpestris ) as top predators. Plankton successions within fish and amphibian lakes differed markedly from each other. Throughout the year rotifers numerically dominated within the minnow lakes, while pigmented copepods (Genera Heterocope, Acanthodiaptomus , Arctodiaptomus , Mixodiaptomus ) and Daphnia were prominent in the amphibian lakes, at least early during the ice-free period. We argue that size-selective predation by minnows was the ultimate reason for this predominance of smaller zooplankton. While one of the minnow lakes was characterized by a succession of spatially and temporally segregated rotifer species, the other minnow lake permitted the development of populations of small-sized Bosmina and Ceriodaphnia during summer, probably due to the existence of a strong oxycline allowing zooplankton crustaceans to avoid predation from shore-based shoals of minnows. Once trout were introduced into this lake, minnows were visibly reduced in abundance. Bosmina and Ceriodaphnia disappeared and Daphnia together with a predacious copepod (Heterocope ) emerged either from egg banks or arrived from nearby source populations. We argue that the crustacean communities within the fishless lakes were adapted to the comparatively weak predation rates of Alpine newts.

  14. Characterization and localization of arginine vasotocin receptors in the brain and kidney of an amphibian

    SciTech Connect

    Boyd, S.K.

    1987-01-01

    Because arginine vasotocin (AVT) activates male sexual behaviors in the rough-skinned newt (Taricha granulosa), quantitative autoradiography with radiolabeled arginine vasopressin (/sup 3/H-AVP) was used to localize and characterize putative AVT receptors in the brain of this amphibian. Binding of /sup 3/H-AVP to sites within the medial pallium was saturable, specific, reversible, of high affinity and low capacity. These binding sites appear to represent authentic central nervous system receptors for AVT. Furthermore, ligand specificity for the binding sites in this amphibian differs from that reported for AVP binding sites in rat brains. Dense concentrations of specific binding sites were located in the olfactory nerve as it entered the olfactory bulb within the medial pallium, dorsal pallium, and amygdala pars lateralis of the telencephalon, and in the tegmental region of the medulla. Concentrations of binding sites differed significantly among various brain regions. A comparison of male and female newts collected during the breeding season revealed no sexual dimorphism. These areas may represent site(s) of action where AVT elicits sexual behaviors in male T. granulosa.

  15. Amphibian and reptile abundance in riparian and upslope areas of five forest types in western Oregon

    USGS Publications Warehouse

    Gomez, D.M.; Anthony, R.G.

    1996-01-01

    We compared species composition and relative abundance of herpetofauna between riparian and upslope habitats among 5 forest types (shrub, open sapling-pole, large sawtimber and old-growth conifer forests, and deciduous forests) in Western Oregon. Riparian- and upslope- associated species were identified based on capture frequencies from pitfall trapping. Species richness was similar among forest types but slightly greater in the shrub stands. The abundances of 3 species differed among forest types. Total captures was highest in deciduous forests, intermediate in the mature conifer forests, and lowest in the 2 young coniferous forests. Species richness was similar between stream and upslope habitats; however, captures were higher in riparian than upslope habitat. Tailed frogs (Ascaphus truei), Dunn's salamanders (Plethodon dunni), roughskin newts(Tanicha granulosa), Pacific giant salamanders (Dicamptodon tenebrosus) and red-legged frogs(Rana aurora) were captured more frequently in riparian than upslope habitats. Of these species the red-legged frog and Pacific giant salamander may depend on riparian habitat for at least part of their life requirements, while tailed frogs, Dunn's salamanders and roughskin newts appear to be riparian associated species. In addition, we found Oregon salamanders (Ensatina eschscholtzi) were associated with upslope habitats. We suggest riparian management zones should be al least 75-100 m on each side of the stream and that management for upslope/and or old forest associates may be equally as important as for riparian species.

  16. Functional joint regeneration is achieved using reintegration mechanism in Xenopus laevis

    PubMed Central

    Yamada, Shigehito

    2016-01-01

    Abstract A functional joint requires integration of multiple tissues: the apposing skeletal elements should form an interlocking structure, and muscles should insert into skeletal tissues via tendons across the joint. Whereas newts can regenerate functional joints after amputation, Xenopus laevis regenerates a cartilaginous rod without joints, a “spike.” Previously we reported that the reintegration mechanism between the remaining and regenerated tissues has a significant effect on regenerating joint morphogenesis during elbow joint regeneration in newt. Based on this insight into the importance of reintegration, we amputated frogs’ limbs at the elbow joint and found that frogs could regenerate a functional elbow joint between the remaining tissues and regenerated spike. During regeneration, the regenerating cartilage was partially connected to the remaining articular cartilage to reform the interlocking structure of the elbow joint at the proximal end of the spike. Furthermore, the muscles of the remaining part inserted into the regenerated spike cartilage via tendons. This study might open up an avenue for analyzing molecular and cellular mechanisms of joint regeneration using Xenopus. PMID:27499877

  17. Urodelean amphibians in studies on microgravity: effects upon organ and tissue regeneration

    NASA Astrophysics Data System (ADS)

    Grigoryan, E. N.; Mitashov, V. I.; Anton, H. J.

    Results obtained from nine experiments performed onboard Russian biosatellites have shown that microgravity promotes tissue regeneration in the newt, Pleurodeles waltl. The effect has been reproduced in all flights and on a clinostat as well for eye tissues (lens and retina), limbs and tail. The effect was demonstrated in 1.5- to 2 -fold increase in cell proliferation in the early stages of regeneration in space flight. Animals "flown" intact and operated after flight regenerated faster than control ones and showed long-lasting micro-"g" effect. The most recent experiment flew aboard the Bion-11 biosatellite. This test was performed for study on microgravity effect on neural retina regeneration after optic nerve lesioning in the newt. Obtained results confirmed our previous information about intensification of regenerative processes in detached neural retina in urodela exposed to simulated weightlessness (Grigoryan et al., 1998). In particular, we found the increase and activation of cell populations participating in neural retina restoration and maintenance of retinal structure. Our findings suggest that promoting effect of microgravity upon regeneration could be influenced by several factors, largely influenced by a response of the whole organism to changed gravity vector. We hypothesized the synthesis of the specific range of stress proteins induced by micro-"g" and their regulative role in cell proliferation. Such a hypothesis for the existence of "altered gravity stress proteins" is discussed.

  18. Le protée est-il équipé pour le magnétotactisme ?

    NASA Astrophysics Data System (ADS)

    Bouquerel, Hélène; Valet, Jean-Pierre

    2005-07-01

    It was suggested that the proteus blind cave salamander can sense the geomagnetic field using magnetic crystals (like magnetite). We attempted to check this hypothesis by measuring the magnetization and the magnetic mineralogy of proteus from the Moulis CNRS underground laboratory. The abdomen and the rear legs of the animals were the unique body parts that revealed a detectable saturation magnetization in the order of 10 -9 A m 2. Because this magnetization was carried by magnetite crystals that have the same magnetic properties as the soil sampled in the cave, it is likely that they were ingested by the animals. Thus these experiments did not detect any crystal that would be responsible for magnetotactism. These results are in contrast with those published for the newt [J. Brassart, J.L. Kirschvink, J.B. Phillips, S.C. Borland, Ferromagnetic material in the eastern red-spotted newt, J. Exp. Biol. 202 (1999) 3155]. However the cryogenic magnetometers do not allow us to detect very small amounts of monodomain grains. This prevents us from any definite conclusion until the construction of a very sensitive cryogenic gradiometer. To cite this article: H. Bouquerel, J.-P. Valet, C. R. Geoscience 337 (2005).

  19. Foton-M3 Unmanned Russian Research Satellite- Development, Implementation and Operations

    NASA Astrophysics Data System (ADS)

    Ilyin, Eugene A.; Skidmore, Michael G.

    2008-06-01

    The Foton-M3 spacecraft launched from Baikonur Cosmodrome (Kazakhstan) on 14 September 2007 and landed 12 days later approximately 130 km south of Kustanay, Northern Kazakhstan. Following the successful National Aeronautics and Space Administration (NASA) and Institute for Biomedical Problems (IMBP) collaboration on the Russian Foton-M2 spaceflight (June 2005), IMBP invited NASA to continue and broaden its participation in four Russian biomedical studies on the Foton-M3 spaceflight. Where the Foton-M2 collaboration had been accomplished without an exchange of funds, the basis for the ongoing bilateral interaction on Foton-M3 was both a cooperative Space Act Agreement and a NASA contract with IMBP. As in Foton-M2, NASA scientists agreed to focus their efforts on research that would be complementary and would facilitate the accomplishment of the original Russian science goals. Foton-M3 hardware enhancements included NASA inserts installed in the IMBP flight hardware to provide programmable in-flight video recording for newts and geckos, drinking water for the geckos, and a preflight "shower" of Bromodeoxyuridine (BrdU) for the newts.

  20. An advanced deterministic method for spent fuel criticality safety analysis

    SciTech Connect

    DeHart, M.D.

    1998-01-01

    Over the past two decades, criticality safety analysts have come to rely to a large extent on Monte Carlo methods for criticality calculations. Monte Carlo has become popular because of its capability to model complex, non-orthogonal configurations or fissile materials, typical of real world problems. Over the last few years, however, interest in determinist transport methods has been revived, due shortcomings in the stochastic nature of Monte Carlo approaches for certain types of analyses. Specifically, deterministic methods are superior to stochastic methods for calculations requiring accurate neutron density distributions or differential fluxes. Although Monte Carlo methods are well suited for eigenvalue calculations, they lack the localized detail necessary to assess uncertainties and sensitivities important in determining a range of applicability. Monte Carlo methods are also inefficient as a transport solution for multiple pin depletion methods. Discrete ordinates methods have long been recognized as one of the most rigorous and accurate approximations used to solve the transport equation. However, until recently, geometric constraints in finite differencing schemes have made discrete ordinates methods impractical for non-orthogonal configurations such as reactor fuel assemblies. The development of an extended step characteristic (ESC) technique removes the grid structure limitations of traditional discrete ordinates methods. The NEWT computer code, a discrete ordinates code built upon the ESC formalism, is being developed as part of the SCALE code system. This paper will demonstrate the power, versatility, and applicability of NEWT as a state-of-the-art solution for current computational needs.

  1. Microelasticity of Single Mitotic Chromosomes

    NASA Astrophysics Data System (ADS)

    Poirier, Michael; Eroglu, Sertac; Chatenay, Didier; Marko, John F.; Hirano, Tatsuya

    2000-03-01

    The force-extension behavior of mitotic chromosomes from the newt TVI tumor cell line was studied using micropipette manipulation and force measuring techniques. Reversible, linear elastic response was observed for extensions up to 5 times the native length; the force required to double chromosome length was 1 nanonewton (nN). For further elongations, the linear response teminates at a force plateau of 15 nN and at an extension of 20x. Beyond this extension, the chromosome breaks at elongations between 20x and 70x. These results will be compared to the similar behavior of mitotic chromosomes from explanted newt cells (Poirier, Eroglu, Chatenay and Marko, Mol. Biol. Cell, in press). Also, the effect of biochemical modifications on the elasticity was studied. Ethidium Bromide, which binds to DNA, induces up to a 10 times increase in the Young's modulus. Anti-XCAP-E, which binds to a putative chromosome folding protein, induces up to a 2 times increase in the Young's modulus. Preliminary results on the dynamical relaxation of chromosomes will also be presented. Support of this research through a Biomedical Engineering Research Grant from The Whitaker Foundation is gratefully acknowledged.

  2. Skin damage in adult amphibians after chronic exposure to ultraviolet radiation.

    PubMed

    Zavanella, T; Losa, M

    1981-10-01

    The effects of repeated UV exposure on the skin of the European crested newt, Triturus cristatus carnifex, have been investigated. The animals were irradiated 3 times per week with a Westinghouse FS40T12 fluorescent sun lamp (wavelength spectrum 275-350 nm). Two groups of animals received the same total fluence of 1.3 x 10(5) J/m(2) in single fluences of either 1570 J/m(2) (group A) or 9430 J/m(2) (group C), and one group received a total fluence of 2.6 x 10(5) J/m(2) in single fluences of 4710 J/m(2) (group B). All the animals were killed in 7 months after the first UV exposure, but at different intervals after the last exposure. Striking epidermal hyperplasia was found in the newts irradiated at the lower fluence rate group (group A). In the animals given the higher total fluence (group B), the most prominent skin changes were dermal fibrosis and irregular thinning and thickening of the epidermis. No significant skin changes were found in group C, in which if there had been UV lesions, they had been repaired during the 5 month interval between the last irradiation and the killing of the animals. No skin tumors developed in any experimental group. PMID:7312954

  3. High gene flow between alternative morphs and the evolutionary persistence of facultative paedomorphosis.

    PubMed

    Oromi, Neus; Michaux, Johan; Denoël, Mathieu

    2016-01-01

    Paedomorphosis and metamorphosis are two major developmental processes that characterize the evolution of complex life cycles in many lineages. Whereas these processes were fixed in some taxa, they remained facultative in others, with alternative phenotypes expressed in the same populations. From a genetic perspective, it is still unknown whether such phenotypes form a single population or whether they show some patterns of isolation in syntopy. This has deep implications for understanding the evolution of the phenotypes, i.e. towards their persistence or their fixation and speciation. Newts and salamanders are excellent models to test this hypothesis because they exhibit both developmental processes in their populations: the aquatic paedomorphs retain gills, whereas the metamorphs are able to colonize land. Using microsatellite data of coexisting paedomorphic and metamorphic palmate newts (Lissotriton helveticus), we found that they formed a panmictic population, which evidences sexual compatibility between the two phenotypes. The high gene flow could be understood as an adaptation to unstable habitats in which phenotypic plasticity is favored over the fixation of developmental alternatives. This makes then possible the persistence of a polyphenism: only metamorphosis could be maintained in case of occasional drying whereas paedomorphosis could offer specific advantages in organisms remaining in water. PMID:27534370

  4. Developmental alterations in centrosome integrity contribute to the post-mitotic state of mammalian cardiomyocytes

    PubMed Central

    Zebrowski, David C; Vergarajauregui, Silvia; Wu, Chi-Chung; Piatkowski, Tanja; Becker, Robert; Leone, Marina; Hirth, Sofia; Ricciardi, Filomena; Falk, Nathalie; Giessl, Andreas; Just, Steffen; Braun, Thomas; Weidinger, Gilbert; Engel, Felix B

    2015-01-01

    Mammalian cardiomyocytes become post-mitotic shortly after birth. Understanding how this occurs is highly relevant to cardiac regenerative therapy. Yet, how cardiomyocytes achieve and maintain a post-mitotic state is unknown. Here, we show that cardiomyocyte centrosome integrity is lost shortly after birth. This is coupled with relocalization of various centrosome proteins to the nuclear envelope. Consequently, postnatal cardiomyocytes are unable to undergo ciliogenesis and the nuclear envelope adopts the function as cellular microtubule organizing center. Loss of centrosome integrity is associated with, and can promote, cardiomyocyte G0/G1 cell cycle arrest suggesting that centrosome disassembly is developmentally utilized to achieve the post-mitotic state in mammalian cardiomyocytes. Adult cardiomyocytes of zebrafish and newt, which are able to proliferate, maintain centrosome integrity. Collectively, our data provide a novel mechanism underlying the post-mitotic state of mammalian cardiomyocytes as well as a potential explanation for why zebrafish and newts, but not mammals, can regenerate their heart. DOI: http://dx.doi.org/10.7554/eLife.05563.001 PMID:26247711

  5. Side-by-side secretion of Late Palaeozoic diverged courtship pheromones in an aquatic salamander.

    PubMed

    Van Bocxlaer, Ines; Treer, Dag; Maex, Margo; Vandebergh, Wim; Janssenswillen, Sunita; Stegen, Gwij; Kok, Philippe; Willaert, Bert; Matthijs, Severine; Martens, Erik; Mortier, Anneleen; de Greve, Henri; Proost, Paul; Bossuyt, Franky

    2015-03-22

    Males of the advanced salamanders (Salamandroidea) attain internal fertilization without a copulatory organ by depositing a spermatophore on the substrate in the environment, which females subsequently take up with their cloaca. The aquatically reproducing modern Eurasian newts (Salamandridae) have taken this to extremes, because most species do not display close physical contact during courtship, but instead largely rely on females following the male track at spermatophore deposition. Although pheromones have been widely assumed to represent an important aspect of male courtship, molecules able to induce the female following behaviour that is the prelude for successful insemination have not yet been identified. Here, we show that uncleaved sodefrin precursor-like factor (SPF) protein pheromones are sufficient to elicit such behaviour in female palmate newts (Lissotriton helveticus). Combined transcriptomic and proteomic evidence shows that males simultaneously tail-fan multiple ca 20 kDa glycosylated SPF proteins during courtship. Notably, molecular dating estimates show that the diversification of these proteins already started in the late Palaeozoic, about 300 million years ago. Our study thus not only extends the use of uncleaved SPF proteins outside terrestrially reproducing plethodontid salamanders, but also reveals one of the oldest vertebrate pheromone systems.

  6. Detrimental Effects of Zinc Oxide Nanoparticles on Amphibian Life Stages.

    PubMed

    Spence, Austin Reid; Hopkins, Gareth Rowland; Neuman-Lee, Lorin Anne; Smith, Geoffrey David Stuart; Brodie, Edmund Darrell; French, Susannah Smith

    2016-08-01

    While the use of nanoparticles has dramatically increased in recent years, the ecological consequences are not well known. In particular, little research has been done to investigate the potentially detrimental effects of nanoparticles on amphibians, especially across all life-history stages of salamanders and newts (caudates). To address this dearth in knowledge, we examined the effects of zinc oxide (ZnO) nanoparticles on egg, larval, and adult Rough-skinned Newts (Taricha granulosa). Chronic toxicity was tested on eggs and larvae, and acute toxicity was tested on eggs, larvae, and adults. For eggs, chronic exposure to ZnO nanoparticles caused higher mortality at 10.0 and 100.0 mg L(-1) compared to 0.0, 0.1, and 1.0 mg L(-1) . When given an acute exposure (24 hr) to 10.0 mg L(-1) nanoparticles at a late developmental stage, larvae hatched 5 days early, at a decreased developmental stage, and smaller size compared to the control. Chronic and acute exposure of larvae increased mortality up to 75% at both 10.0 and 100.0 mg L(-1) and exhibited sublethal effects, most dramatically, severe gill degradation. These results suggest nanoparticles can have lethal and sublethal effects on all life stages of amphibians. PMID:27453487

  7. Contributions to the functional morphology of caudate skulls: kinetic and akinetic forms.

    PubMed

    Natchev, Nikolay; Handschuh, Stephan; Lukanov, Simeon; Tzankov, Nikolay; Naumov, Borislav; Werneburg, Ingmar

    2016-01-01

    A strongly ossified and rigid skull roof, which prevents parietal kinesis, has been reported for the adults of all amphibian clades. Our μ-CT investigations revealed that the Buresch's newt (Triturus ivanbureschi) possess a peculiar cranial construction. In addition to the typical amphibian pleurokinetic articulation between skull roof and palatoquadrate associated structures, we found flexible connections between nasals and frontals (prokinesis), vomer and parasphenoid (palatokinesis), and between frontals and parietals (mesokinesis). This is the first description of mesokinesis in urodelans. The construction of the skull in the Buresch's newts also indicates the presence of an articulation between parietals and the exocipitals, discussed as a possible kind of metakinesis. The specific combination of pleuro-, pro-, meso-, palato-, and metakinetic skull articulations indicate to a new kind of kinetic systems unknown for urodelans to this date. We discuss the possible neotenic origin of the skull kinesis and pose the hypothesis that the kinesis in T. ivanbureschi increases the efficiency of fast jaw closure. For that, we compared the construction of the skull in T. ivanbureschi to the akinetic skull of the Common fire salamander Salamandra salamandra. We hypothesize that the design of the skull in the purely terrestrial living salamander shows a similar degree of intracranial mobility. However, this mobility is permitted by elasticity of some bones and not by true articulation between them. We comment on the possible relation between the skull construction and the form of prey shaking mechanism that the species apply to immobilize their victims.

  8. Contributions to the functional morphology of caudate skulls: kinetic and akinetic forms.

    PubMed

    Natchev, Nikolay; Handschuh, Stephan; Lukanov, Simeon; Tzankov, Nikolay; Naumov, Borislav; Werneburg, Ingmar

    2016-01-01

    A strongly ossified and rigid skull roof, which prevents parietal kinesis, has been reported for the adults of all amphibian clades. Our μ-CT investigations revealed that the Buresch's newt (Triturus ivanbureschi) possess a peculiar cranial construction. In addition to the typical amphibian pleurokinetic articulation between skull roof and palatoquadrate associated structures, we found flexible connections between nasals and frontals (prokinesis), vomer and parasphenoid (palatokinesis), and between frontals and parietals (mesokinesis). This is the first description of mesokinesis in urodelans. The construction of the skull in the Buresch's newts also indicates the presence of an articulation between parietals and the exocipitals, discussed as a possible kind of metakinesis. The specific combination of pleuro-, pro-, meso-, palato-, and metakinetic skull articulations indicate to a new kind of kinetic systems unknown for urodelans to this date. We discuss the possible neotenic origin of the skull kinesis and pose the hypothesis that the kinesis in T. ivanbureschi increases the efficiency of fast jaw closure. For that, we compared the construction of the skull in T. ivanbureschi to the akinetic skull of the Common fire salamander Salamandra salamandra. We hypothesize that the design of the skull in the purely terrestrial living salamander shows a similar degree of intracranial mobility. However, this mobility is permitted by elasticity of some bones and not by true articulation between them. We comment on the possible relation between the skull construction and the form of prey shaking mechanism that the species apply to immobilize their victims. PMID:27688958

  9. Potential for local adaptation in response to an anthropogenic agent of selection: effects of road deicing salts on amphibian embryonic survival and development

    PubMed Central

    Hopkins, Gareth R; French, Susannah S; Brodie, Edmund D

    2013-01-01

    The application of millions of tons of road deicing salts every winter in North America presents significant survival challenges to amphibians inhabiting roadside habitats. While much is known of the effects of NaCl on anuran tadpoles, less is known of effects on amphibian eggs, or any caudate life stage. In addition, little is known of the effects of MgCl2, which is now the 2nd most commonly used road deicer. Most studies have considered amphibians to be helpless victims of deicing salts, and ignore the possibility of the evolution of local adaptation to this stressor. We attempt to address these knowledge gaps and explore this evolutionary potential by examining the effects of NaCl and MgCl2 on the survival and development of eggs from different female rough-skinned newts (Taricha granulosa) from the same population. We demonstrate that both salts, at environmentally relevant concentrations, severely affect the embryonic survival and development of this amphibian, but that the effects of the salt are dependent on the identity of the mother. This female × treatment interaction results in substantial variation in tolerance to road deicing salts among newt families, providing the raw material necessary for natural selection and the evolution of local adaptation in this amphibian. PMID:23467723

  10. Developmental and evolutionary history affect survival in stressful environments.

    PubMed

    Hopkins, Gareth R; Brodie, Edmund D; French, Susannah S

    2014-01-01

    The world is increasingly impacted by a variety of stressors that have the potential to differentially influence life history stages of organisms. Organisms have evolved to cope with some stressors, while with others they have little capacity. It is thus important to understand the effects of both developmental and evolutionary history on survival in stressful environments. We present evidence of the effects of both developmental and evolutionary history on survival of a freshwater vertebrate, the rough-skinned newt (Taricha granulosa) in an osmotically stressful environment. We compared the survival of larvae in either NaCl or MgCl2 that were exposed to salinity either as larvae only or as embryos as well. Embryonic exposure to salinity led to greater mortality of newt larvae than larval exposure alone, and this reduced survival probability was strongly linked to the carry-over effect of stunted embryonic growth in salts. Larval survival was also dependent on the type of salt (NaCl or MgCl2) the larvae were exposed to, and was lowest in MgCl2, a widely-used chemical deicer that, unlike NaCl, amphibian larvae do not have an evolutionary history of regulating at high levels. Both developmental and evolutionary history are critical factors in determining survival in this stressful environment, a pattern that may have widespread implications for the survival of animals increasingly impacted by substances with which they have little evolutionary history.

  11. Potential for local adaptation in response to an anthropogenic agent of selection: effects of road deicing salts on amphibian embryonic survival and development.

    PubMed

    Hopkins, Gareth R; French, Susannah S; Brodie, Edmund D

    2013-02-01

    The application of millions of tons of road deicing salts every winter in North America presents significant survival challenges to amphibians inhabiting roadside habitats. While much is known of the effects of NaCl on anuran tadpoles, less is known of effects on amphibian eggs, or any caudate life stage. In addition, little is known of the effects of MgCl2, which is now the 2nd most commonly used road deicer. Most studies have considered amphibians to be helpless victims of deicing salts, and ignore the possibility of the evolution of local adaptation to this stressor. We attempt to address these knowledge gaps and explore this evolutionary potential by examining the effects of NaCl and MgCl2 on the survival and development of eggs from different female rough-skinned newts (Taricha granulosa) from the same population. We demonstrate that both salts, at environmentally relevant concentrations, severely affect the embryonic survival and development of this amphibian, but that the effects of the salt are dependent on the identity of the mother. This female × treatment interaction results in substantial variation in tolerance to road deicing salts among newt families, providing the raw material necessary for natural selection and the evolution of local adaptation in this amphibian.

  12. Developmental and Evolutionary History Affect Survival in Stressful Environments

    PubMed Central

    Hopkins, Gareth R.; Brodie, Edmund D.; French, Susannah S.

    2014-01-01

    The world is increasingly impacted by a variety of stressors that have the potential to differentially influence life history stages of organisms. Organisms have evolved to cope with some stressors, while with others they have little capacity. It is thus important to understand the effects of both developmental and evolutionary history on survival in stressful environments. We present evidence of the effects of both developmental and evolutionary history on survival of a freshwater vertebrate, the rough-skinned newt (Taricha granulosa) in an osmotically stressful environment. We compared the survival of larvae in either NaCl or MgCl2 that were exposed to salinity either as larvae only or as embryos as well. Embryonic exposure to salinity led to greater mortality of newt larvae than larval exposure alone, and this reduced survival probability was strongly linked to the carry-over effect of stunted embryonic growth in salts. Larval survival was also dependent on the type of salt (NaCl or MgCl2) the larvae were exposed to, and was lowest in MgCl2, a widely-used chemical deicer that, unlike NaCl, amphibian larvae do not have an evolutionary history of regulating at high levels. Both developmental and evolutionary history are critical factors in determining survival in this stressful environment, a pattern that may have widespread implications for the survival of animals increasingly impacted by substances with which they have little evolutionary history. PMID:24748021

  13. Contributions to the functional morphology of caudate skulls: kinetic and akinetic forms

    PubMed Central

    Handschuh, Stephan; Lukanov, Simeon; Naumov, Borislav

    2016-01-01

    A strongly ossified and rigid skull roof, which prevents parietal kinesis, has been reported for the adults of all amphibian clades. Our μ-CT investigations revealed that the Buresch’s newt (Triturus ivanbureschi) possess a peculiar cranial construction. In addition to the typical amphibian pleurokinetic articulation between skull roof and palatoquadrate associated structures, we found flexible connections between nasals and frontals (prokinesis), vomer and parasphenoid (palatokinesis), and between frontals and parietals (mesokinesis). This is the first description of mesokinesis in urodelans. The construction of the skull in the Buresch’s newts also indicates the presence of an articulation between parietals and the exocipitals, discussed as a possible kind of metakinesis. The specific combination of pleuro-, pro-, meso-, palato-, and metakinetic skull articulations indicate to a new kind of kinetic systems unknown for urodelans to this date. We discuss the possible neotenic origin of the skull kinesis and pose the hypothesis that the kinesis in T. ivanbureschi increases the efficiency of fast jaw closure. For that, we compared the construction of the skull in T. ivanbureschi to the akinetic skull of the Common fire salamander Salamandra salamandra. We hypothesize that the design of the skull in the purely terrestrial living salamander shows a similar degree of intracranial mobility. However, this mobility is permitted by elasticity of some bones and not by true articulation between them. We comment on the possible relation between the skull construction and the form of prey shaking mechanism that the species apply to immobilize their victims.

  14. Functional joint regeneration is achieved using reintegration mechanism in Xenopus laevis.

    PubMed

    Tsutsumi, Rio; Yamada, Shigehito; Agata, Kiyokazu

    2016-02-01

    A functional joint requires integration of multiple tissues: the apposing skeletal elements should form an interlocking structure, and muscles should insert into skeletal tissues via tendons across the joint. Whereas newts can regenerate functional joints after amputation, Xenopus laevis regenerates a cartilaginous rod without joints, a "spike." Previously we reported that the reintegration mechanism between the remaining and regenerated tissues has a significant effect on regenerating joint morphogenesis during elbow joint regeneration in newt. Based on this insight into the importance of reintegration, we amputated frogs' limbs at the elbow joint and found that frogs could regenerate a functional elbow joint between the remaining tissues and regenerated spike. During regeneration, the regenerating cartilage was partially connected to the remaining articular cartilage to reform the interlocking structure of the elbow joint at the proximal end of the spike. Furthermore, the muscles of the remaining part inserted into the regenerated spike cartilage via tendons. This study might open up an avenue for analyzing molecular and cellular mechanisms of joint regeneration using Xenopus. PMID:27499877

  15. Urodelean amphibians in studies on microgravity: effects upon organ and tissue regeneration.

    PubMed

    Grigoryan, E N; Mitashov, V I; Anton, H J

    2002-01-01

    Results obtained from nine experiments performed onboard Russian biosatellites have shown that microgravity promotes tissue regeneration in the newt, Pleurodeles waltl. The effect has been reproduced in all flights and on a clinostat as well for eye tissues (lens and retina), limbs and tail. The effect was demonstrated in 1.5- to 2-fold increase in cell proliferation in the early stages of regeneration in space flight. Animals "flown" intact and operated after flight regenerated faster than control ones and showed long-lasting micro-"g" effect. The most recent experiment flew aboard the Bion-11 biosatellite. This test was performed for study on microgravity effect on neural retina regeneration after optic nerve lesioning in the newt. Obtained results confirmed our previous information about intensification of regenerative processes in detached neural retina in urodela exposed to simulated weightlessness (Grigoryan et al., 1998). In particular, we found the increase and activation of cell populations participating in neural retina restoration and maintenance of retinal structure. Our findings suggest that promoting effect of microgravity upon regeneration could be influenced by several factors, largely influenced by a response of the whole organism to changed gravity vector. We hypothesized the synthesis of the specific range of stress proteins induced by micro-"g" and their regulative role in cell proliferation. Such a hypothesis for the existence of "altered gravity stress proteins" is discussed.

  16. Chromosome motion during attachment to the vertebrate spindle: initial saltatory-like behavior of chromosomes and quantitative analysis of force production by nascent kinetochore fibers

    PubMed Central

    1991-01-01

    Before forming a monopolar attachment to the closest spindle pole, chromosomes attaching in newt (Taricha granulosa) pneumocytes generally reside in an optically clear region of cytoplasm that is largely devoid of cytoskeletal components, organelles, and other chromosomes. We have previously demonstrated that chromosome attachment in these cells occurs when an astral microtubule contacts one of the kinetochores (Hayden, J., S. S. Bowser, and C. L. Rieder. 1990. J. Cell Biol. 111:1039-1045), and that once this association is established the chromosome can be transported poleward along the surface of the microtubule (Rieder, C. L., and S. P. Alexander. 1990. J. Cell Biol. 110:81-95). In the study reported here we used video enhanced differential interference contrast light microscopy and digital image processing to compare, at high spatial and temporal resolution (0.1 microns and 0.93 s, respectively), the microtubule-mediated poleward movement of attaching chromosomes and poleward moving particles on the spindle. The results of this analysis demonstrate obvious similarities between minus end-directed particle motion on the newt pneumocyte spindle and the motion of attaching chromosomes. This is consistent with the hypothesis that both are driven by a similar force-generating mechanism. We then used the Brownian displacements of particles in the vicinity of attaching chromosomes to calculate the apparent viscosity of cytoplasm through which the chromosomes were moving. From these data, and that from our kinetic analyses and previous work, we calculate the force-producing potential of nascent kinetochore fibers in newt pneumocytes to be approximately 0.1-7.4 x 10(-6) dyn/microtubule) This is essentially equivalent to that calculated by Nicklas (Nicklas, R.B. 1988. Annu. Rev. Biophys. Biophys. Chem. 17:431- 449) for prometaphase (4 x 10(-6) dyn/microtubule) and anaphase (5 x 10(-6) dyn/microtubule) chromosomes in Melanoplus. Thus, within the limits of experimental

  17. A revision of the Neotropical species of Bolitogyrus Chevrolat, a geographically disjunct lineage of Staphylinini (Coleoptera, Staphylinidae).

    PubMed

    Brunke, Adam J; Solodovnikov, Alexey

    2014-01-01

    The Neotropical species of the rarely collected genus Bolitogyrus (Coleoptera: Staphylinidae: Staphylininae: Staphylinini) are revised. The genus exhibits an uncommon, disjunct distribution between the Neotropical and Oriental Regions and is of unknown phylogenetic position within Staphylinini. Morphological evolution remarkable for Staphylinini was discovered within Bolitogyrus, including sexually dimorphic modifications of the pronotum that may be involved in male competition for females. rSEM interactive animations were used to establish morphological species boundaries between two highly variable species and are provided to illustrate diagnostic characters of the genitalia in unconventional views. The genus is redescribed based on the world fauna and twenty-eight Neotropical species are considered valid. Of these, nineteen are described as new to science: Bolitogyrus ashei sp. n.; B. apicofasciatus sp. n.; B. brevistellus sp. n.; B. bufo sp. n.; B. cheungi sp. n.; B. cornutus sp. n.; B. divisus sp. n.; B. falini sp. n.; B. gracilis sp. n.; B. inexspectatus sp. n.; B. longistellus sp. n.; B. marquezi sp. n.; B. newtoni sp. n.; B. pseudotortifolius sp. n.; B. pulchrus sp. n.; B. silex sp. n.; B. thomasi sp. n.; B. tortifolius sp. n.; and B. viridescens sp. n. Bolitogyrus sallei (Kraatz), stat. r. is removed from synonymy with B. buphthalmus (Erichson) and the following new synonyms are proposed: Cyrtothorax cyanescens Sharp, 1884, syn. n. = Quedius buphthalmus Erichson, 1840; C. nevermanni Scheerpeltz, 1974, syn. n. = C. costaricensis Wendeler, 1927. A summary of all available bionomic and distributional data, as well as an illustrated identification key to and diagnoses of all Neotropical species are provided. PMID:25061393

  18. A revision of the Neotropical species of Bolitogyrus Chevrolat, a geographically disjunct lineage of Staphylinini (Coleoptera, Staphylinidae)

    PubMed Central

    Brunke, Adam J.; Solodovnikov, Alexey

    2014-01-01

    Abstract The Neotropical species of the rarely collected genus Bolitogyrus (Coleoptera: Staphylinidae: Staphylininae: Staphylinini) are revised. The genus exhibits an uncommon, disjunct distribution between the Neotropical and Oriental Regions and is of unknown phylogenetic position within Staphylinini. Morphological evolution remarkable for Staphylinini was discovered within Bolitogyrus, including sexually dimorphic modifications of the pronotum that may be involved in male competition for females. rSEM interactive animations were used to establish morphological species boundaries between two highly variable species and are provided to illustrate diagnostic characters of the genitalia in unconventional views. The genus is redescribed based on the world fauna and twenty-eight Neotropical species are considered valid. Of these, nineteen are described as new to science: Bolitogyrus ashei sp. n.; B. apicofasciatus sp. n.; B. brevistellus sp. n.; B. bufo sp. n.; B. cheungi sp. n.; B. cornutus sp. n.; B. divisus sp. n.; B. falini sp. n.; B. gracilis sp. n.; B. inexspectatus sp. n.; B. longistellus sp. n.; B. marquezi sp. n.; B. newtoni sp. n.; B. pseudotortifolius sp. n.; B. pulchrus sp. n.; B. silex sp. n.; B. thomasi sp. n.; B. tortifolius sp. n.; and B. viridescens sp. n. Bolitogyrus sallei (Kraatz), stat. r. is removed from synonymy with B. buphthalmus (Erichson) and the following new synonyms are proposed: Cyrtothorax cyanescens Sharp, 1884, syn. n. = Quedius buphthalmus Erichson, 1840; C. nevermanni Scheerpeltz, 1974, syn. n. = C. costaricensis Wendeler, 1927. A summary of all available bionomic and distributional data, as well as an illustrated identification key to and diagnoses of all Neotropical species are provided. PMID:25061393

  19. Wildlife disease. Recent introduction of a chytrid fungus endangers Western Palearctic salamanders.

    PubMed

    Martel, A; Blooi, M; Adriaensen, C; Van Rooij, P; Beukema, W; Fisher, M C; Farrer, R A; Schmidt, B R; Tobler, U; Goka, K; Lips, K R; Muletz, C; Zamudio, K R; Bosch, J; Lötters, S; Wombwell, E; Garner, T W J; Cunningham, A A; Spitzen-van der Sluijs, A; Salvidio, S; Ducatelle, R; Nishikawa, K; Nguyen, T T; Kolby, J E; Van Bocxlaer, I; Bossuyt, F; Pasmans, F

    2014-10-31

    Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss.

  20. Turning terminally differentiated skeletal muscle cells into regenerative progenitors.

    PubMed

    Wang, Heng; Lööf, Sara; Borg, Paula; Nader, Gustavo A; Blau, Helen M; Simon, András

    2015-01-01

    The ability to repeatedly regenerate limbs during the entire lifespan of an animal is restricted to certain salamander species among vertebrates. This ability involves dedifferentiation of post-mitotic cells into progenitors that in turn form new structures. A long-term enigma has been how injury leads to dedifferentiation. Here we show that skeletal muscle dedifferentiation during newt limb regeneration depends on a programmed cell death response by myofibres. We find that programmed cell death-induced muscle fragmentation produces a population of 'undead' intermediate cells, which have the capacity to resume proliferation and contribute to muscle regeneration. We demonstrate the derivation of proliferating progeny from differentiated, multinucleated muscle cells by first inducing and subsequently intercepting a programmed cell death response. We conclude that cell survival may be manifested by the production of a dedifferentiated cell with broader potential and that the diversion of a programmed cell death response is an instrument to achieve dedifferentiation. PMID:26243583

  1. Brain and pineal 7α-hydroxypregnenolone stimulating locomotor activity: identification, mode of action and regulation of biosynthesis.

    PubMed

    Tsutsui, Kazuyoshi; Haraguchi, Shogo; Fukada, Yoshitaka; Vaudry, Hubert

    2013-08-01

    Biologically active steroids synthesized in the central and peripheral nervous systems are termed neurosteroids. However, the biosynthetic pathways leading to the formation of neurosteroids are still incompletely elucidated. 7α-Hydroxypregnenolone, a novel bioactive neurosteroid stimulating locomotor activity, has been recently identified in the brain of newts and quail. Subsequently, the mode of action and regulation of biosynthesis of 7α-hydroxypregnenolone have been determined. Moreover, recent studies on birds have demonstrated that the pineal gland, an endocrine organ located close to the brain, is an important site of production of neurosteroids de novo from cholesterol. 7α-Hydroxypregnenolone is a major pineal neurosteroid that stimulates locomotor activity in juvenile chickens, connecting light-induced gene expression with locomotion. This review summarizes the advances in our understanding of the identification, mode of action and regulation of biosynthesis of brain and pineal 7α-hydroxypregnenolone, a potent stimulator of locomotor activity.

  2. NASDA aquatic animal experiment facilities for Space Shuttle and ISS.

    PubMed

    Uchida, Satoko; Masukawa, Mitsuyo; Kamigaichi, Shigeki

    2002-01-01

    National Space Development Agency of Japan (NASDA) has developed aquatic animal experiment facilities for NASA Space Shuttle use. Vestibular Function Experiment Unit (VFEU) was firstly designed and developed for physiological research using carp in Spacelab-J (SL-J, STS-47) mission. It was modified as Aquatic Animal Experiment Unit (AAEU) to accommodate small aquatic animals, such as medaka and newt, for second International Microgravity Laboratory (IML-2, STS-65) mission. Then, VFEU was improved to accommodate marine fish and to perform neurobiological experiment for Neurolab (STS-90) and STS-95 missions. We have also developed and used water purification system which was adapted to each facility. Based on these experiences of Space Shuttle missions, we are studying to develop advanced aquatic animal experiment facility for both Space Shuttle and International Space Station (ISS).

  3. Experimental measurements and modeling of impurity transport in the divertor and boundary plasma of DIII-D

    SciTech Connect

    West, W.P.; Brooks, N.H.; Allen, S.L.

    1994-07-01

    Analysis of trace impurity injection experiments on DIII-D during a beam power scan is presented. Spectroscopic measu- rements indicate that as beam power is increased, and concomitantly ELM frequency and scrape-off-layer thickness increase while energy confinement decreases, the core impurity content decreases only slightly. Modeling of the edge plasma using the UEDGE 2D and NEWT1D plasma fluid codes indicate that as beam power is increased, the parallel forces on an impurity ion increase in the direction from the divertor and toward the core plasma. Experiments using the divertor cryopump to induce higher parallel particle flow toward the divertor demonstrate significant reduction in core impurity content. These results indicate that parallel forces on impurity ions in the scrape off layer are playing a significant role in core impurity content.

  4. An orphan gene is necessary for preaxial digit formation during salamander limb development

    PubMed Central

    Kumar, Anoop; Gates, Phillip B.; Czarkwiani, Anna; Brockes, Jeremy P.

    2015-01-01

    Limb development in salamanders differs from other tetrapods in that the first digits to form are the two most anterior (preaxial dominance). This has been proposed as a salamander novelty and its mechanistic basis is unknown. Salamanders are the only adult tetrapods able to regenerate the limb, and the contribution of preaxial dominance to limb regeneration is unclear. Here we show that during early outgrowth of the limb bud, a small cohort of cells express the orphan gene Prod1 together with Bmp2, a critical player in digit condensation in amniotes. Disruption of Prod1 with a gene-editing nuclease abrogates these cells, and blocks formation of the radius and ulna, and outgrowth of the anterior digits. Preaxial dominance is a notable feature of limb regeneration in the larval newt, but this changes abruptly after metamorphosis so that the formation of anterior and posterior digits occurs together within the autopodium resembling an amniote-like pattern. PMID:26498026

  5. Health-effects assessment for acenaphthene

    SciTech Connect

    Not Available

    1987-07-01

    Because of the lack of data for the carcinogenicity and threshold toxicity of acenaphthene risk assessment values cannot be derived. The ambient water-quality criterion of 0.2 mg/l is based on organoleptic data, which has no known relationship to potential human health effects. Acenaphthene has been shown to produce nuclear and cytological changes in microbial and plant species. Results of acenaphthene mutagenicity studies in microorganisms and carcinogenicity study are negative. Despite the negative results in the newt (Triturus cristatus) the fact that acenaphthene is a polynuclear aromatic hydrocarbon (PAH), a class of chemicals that contain carcinogens, the carcinogenic potential of acenaphthene is of great concern. Inadequate evidence to allow any conclusion regarding carcinogenicity for humans appropriately places acenaphthene in EPA Group D.

  6. New Criticality Safety Analysis Capabilities in SCALE 5.1

    SciTech Connect

    Bowman, Stephen M; DeHart, Mark D; Dunn, Michael E; Goluoglu, Sedat; Horwedel, James E; Petrie Jr, Lester M; Rearden, Bradley T; Williams, Mark L

    2007-01-01

    Version 5.1 of the SCALE computer software system developed at Oak Ridge National Laboratory, released in 2006, contains several significant enhancements for nuclear criticality safety analysis. This paper highlights new capabilities in SCALE 5.1, including improved resonance self-shielding capabilities; ENDF/B-VI.7 cross-section and covariance data libraries; HTML output for KENO V.a; analytical calculations of KENO-VI volumes with GeeWiz/KENO3D; new CENTRMST/PMCST modules for processing ENDF/B-VI data in TSUNAMI; SCALE Generalized Geometry Package in NEWT; KENO Monte Carlo depletion in TRITON; and plotting of cross-section and covariance data in Javapeno.

  7. Wake Management Strategies for Reduction of Turbomachinery Fan Noise

    NASA Technical Reports Server (NTRS)

    Waitz, Ian A.

    1998-01-01

    The primary objective of our work was to evaluate and test several wake management schemes for the reduction of turbomachinery fan noise. Throughout the course of this work we relied on several tools. These include 1) Two-dimensional steady boundary-layer and wake analyses using MISES (a thin-shear layer Navier-Stokes code), 2) Two-dimensional unsteady wake-stator interaction simulations using UNSFLO, 3) Three-dimensional, steady Navier-Stokes rotor simulations using NEWT, 4) Internal blade passage design using quasi-one-dimensional passage flow models developed at MIT, 5) Acoustic modeling using LINSUB, 6) Acoustic modeling using VO72, 7) Experiments in a low-speed cascade wind-tunnel, and 8) ADP fan rig tests in the MIT Blowdown Compressor.

  8. Comparative analysis of ear-hole closure identifies epimorphic regeneration as a discrete trait in mammals.

    PubMed

    Gawriluk, Thomas R; Simkin, Jennifer; Thompson, Katherine L; Biswas, Shishir K; Clare-Salzler, Zak; Kimani, John M; Kiama, Stephen G; Smith, Jeramiah J; Ezenwa, Vanessa O; Seifert, Ashley W

    2016-01-01

    Why mammals have poor regenerative ability has remained a long-standing question in biology. In regenerating vertebrates, injury can induce a process known as epimorphic regeneration to replace damaged structures. Using a 4-mm ear punch assay across multiple mammalian species, here we show that several Acomys spp. (spiny mice) and Oryctolagus cuniculus completely regenerate tissue, whereas other rodents including MRL/MpJ 'healer' mice heal similar injuries by scarring. We demonstrate ear-hole closure is independent of ear size, and closure rate can be modelled with a cubic function. Cellular and genetic analyses reveal that injury induces blastema formation in Acomys cahirinus. Despite cell cycle re-entry in Mus musculus and A. cahirinus, efficient cell cycle progression and proliferation only occurs in spiny mice. Together, our data unite blastema-mediated regeneration in spiny mice with regeneration in other vertebrates such as salamanders, newts and zebrafish, where all healthy adults regenerate in response to injury. PMID:27109826

  9. Salamander-Derived, Human-Optimized nAG Protein Suppresses Collagen Synthesis and Increases Collagen Degradation in Primary Human Fibroblasts

    PubMed Central

    Al-Qattan, Mohammad M.; Shier, Medhat K.; Abd-AlWahed, Mervat M.; Mawlana, Ola H.; El-Wetidy, Mohammed S.; Bagayawa, Reginald S.; Ali, Hebatallah H.; Al-Nbaheen, May S.; Aldahmash, Abdullah M.

    2013-01-01

    Unlike humans, salamanders regrow their amputated limbs. Regeneration depends on the presence of regenerating axons which upregulate the expression of newt anterior gradient (nAG) protein. We had the hypothesis that nAG might have an inhibitory effect on collagen production since excessive collagen production results in scarring, which is a major enemy to regeneration. nAG gene was designed, synthesized, and cloned. The cloned vector was then transfected into primary human fibroblasts. The results showed that the expression of nAG protein in primary human fibroblast cells suppresses the expression of collagen I and III, with or without TGF-β1 stimulation. This suppression is due to a dual effect of nAG both by decreasing collagen synthesis and by increasing collagen degradation. Furthermore, nAG had an inhibitory effect on proliferation of transfected fibroblasts. It was concluded that nAG suppresses collagen through multiple effects. PMID:24288677

  10. Ranavirus-associated mass mortality in wild amphibians, the Netherlands, 2010: a first report.

    PubMed

    Kik, Marja; Martel, An; Sluijs, Annemarieke Spitzen-van der; Pasmans, Frank; Wohlsein, Peter; Gröne, Andrea; Rijks, Jolianne M

    2011-11-01

    In 2010, a mass die-off of over 1000 wild water frogs (Pelophylax spp.) and at least 10 common newts (Lissotriton vulgaris) occurred in a pond in The Netherlands. Haemorrhagic disease with hepatomegaly and splenomegaly was evident. Microscopically, multiple organs presented cells with multifocal intracytoplasmic inclusion bodies, in which ranavirus-like particles were demonstrated ultrastructurally. All specimens examined tested positive for ranavirus by PCR. The sequence obtained showed a 100% identity with the one deposited for common midwife toad virus (CMTV). This is the first report of ranavirus-associated mortality in wild amphibian populations in The Netherlands. It is also the first time CMTV or a CMTV-like virus has been reported in these two species in the adult stage and outside of Spain.

  11. From healing to witchcraft: on ritual speech and roboticization in the hospital.

    PubMed

    Pine, Adrienne

    2011-06-01

    Healthcare Information Technology (HIT), touted as a panacea by U.S. political actors ranging from Newt Gingrich to Barack Obama, is central to emerging forms of healthcare governance which Holmes et al.-in their critique of the institutionalization of magical thinking brought about by Orwellian techno-Newspeak-have provocatively labeled fascistic. Drawing from data collected over 3 years of working with and teaching continuing education (CE) courses for thousands of registered nurses as lead political educator for the California Nurses Association/National Nurses Organizing Committee (CNA/NNOC), I argue that HIT is an integral component of a broader technological restructuring of healthcare and thus society, both of which are part of a social discourse that is tied to a transformative system of ritual speech, with profound implications for healthcare work, patient health, and democracy.

  12. Influence of longitudinal whole animal clinorotation on lens, tail, and limb regeneration in urodeles

    NASA Astrophysics Data System (ADS)

    Anton, H. J.; Grigoryan, E. N.; Mitashov, V. I.

    Two species of newts (Urodela) and two types of clinostats for fast clinorotation (60 rpm) were used to investigate the influence of simulated weightlessness on regeneration and to compare results obtained with data from spaceflight experiments. Seven or fourteen days of weightlessness in Russian biosatellites caused acceleration of lens and limb regeneration by an increase in cell proliferation, differentiation, and rate of morphogenesis in comparison with ground controls. After a comparable time of clinorotation the results obtained with Triturus vulgaris using a horizontal clinostat were similar to those found in spaceflight. In contrast, in Pleurodeles waltl using both horizontal and radial clinostats the results were contradictionary compared to Triturus. We speculate that different levels of gravity or/and species specific thresholds for gravitational sensitivity could be responsible for these contradictionary results.

  13. NASDA aquatic animal experiment facilities for space shuttle and ISS

    NASA Astrophysics Data System (ADS)

    Uchida, Satoko; Masukawa, Mitsuyo; Kamigaichi, Shigeki

    National Space Development Agency of Japan (NASDA) has developed aquatic animal experiment facilities for NASA Space Shuttle use. Vestibular Function Experiment Unit (VFEU) was firstly designed and developed for physiological research using carp in Spacelab-J (SL-J, STS-47) mission. It was modified as Aquatic Animal Experiment Unit (AAEU) to accommodate small aquatic animals, such as medaka and newt, for second International Microgravity Laboratory (IML-2, STS-65) mission. Then, VFEU was improved to accommodate marine fish and to perform neurobiological experiment for Neurolab (STS-90) and STS-95 missions. We have also developed and used water purification system which was adapted to each facility. Based on these experiences of Space Shuttle missions, we are studying to develop advanced aquatic animal experiment facility for both Space Shuttle and International Space Station (ISS).

  14. Cold-induced changes in amphibian oocytes

    SciTech Connect

    Angelier, N.; Moreau, N.A.; N'Da, E.A.; Lautredou, N.F. )

    1989-08-01

    Female Pleurodeles waltl newts (Amphibia, urodele), usually raised at 20 degrees C, were submitted to low temperatures; oocytes responded to this cold stress by drastic changes both in lampbrush chromosome structure and in protein pattern. Preexisting lateral loops of lampbrush chromosomes were reduced in size and number, while cold-induced loops which were tremendously developed, occurred on defined bivalents of the oocyte at constant, reproducible sites. A comparison of protein patterns in control and stressed oocytes showed two main differences: in stressed oocytes, overall protein synthesis was reduced, except for a set of polypeptides, the cold-stress proteins; second, there was a striking inversion of the relative amount of beta- and gamma-actin found in the oocyte nucleus before and after cold stress. Whereas beta-actin was the predominant form in control oocytes, gamma-actin became the major form in stressed oocytes.

  15. Trophic specialisations in alternative heterochronic morphs

    NASA Astrophysics Data System (ADS)

    Denoël, Mathieu; Schabetsberger, Robert; Joly, Pierre

    Polymorphisms are suspected of reducing competition among conspecifics in heterogeneous environments by allowing differential resource use. However the adaptive significance of alternative morphs has been poorly documented. The aim of this study is to determine food partitioning of two heterochronic morphs of the Alpine newt, Triturus alpestris, in mountain lakes. The morphs differ in the functional morphology of their feeding apparatus. Only paedomorphs are able to expel water during prey suction behind the mouth through gill slits. We observed a substantial trophic differentiation between morphs in all lakes. Paedomorphs preyed mainly on plankton, whereas metamorphs foraged on terrestrial invertebrates that fell upon the water surface. This resource partitioning may facilitate the coexistence of the alternative morphs in lakes devoid of vertebrate competitors. Food diversity may thus favour the evolutionary maintenance of facultative polymorphism in natural populations.

  16. A phylogeny of the Tylototriton asperrimus group (Caudata: Salamandridae) based on a mitochondrial study: suggestions for a taxonomic revision.

    PubMed

    Yuan, Zhi-Yong; Jiang, Ke; Lü, Shun-Qing; Yang, Jun-Xiao; Nguyen, Quang Truong; Nguyen, Thien Tao; Jin, Jie-Qiong; Che, Jing

    2011-12-01

    A phylogenetic hypothesis for the Asian newts of the Tylototriton asperrimus group was generated using data from two mitochondrial fragments including COI and the ND1-ND2 regions. Four distinct clades (A, B, C, D) were resolved with high nodal support within this monophyletic group. Clade A included T. asperrimus, T. hainanensis, T. notialis, "T. vietnamensis", and two unnamed salamander populations from Vietnam. Clade A, constituted the sister group of clades B + C. Newly identified clade C likely represents a new cryptic species. Clade C was the sister group of T. wenxianensis. The true T. vietnamensis exclusively constituted clade D. Our results bring into question some previous taxonomic decisions, and a revision is required. This study illustrates the necessity to include samples from type localities in taxonomic studies, and highlights the importance of fine-grained geographical sampling.

  17. A Deterministic Study of the Deficiency of the Wigner-Seitz Approximation for Pu/MOX Fuel Pins

    SciTech Connect

    DeHart, M.D.

    1999-09-27

    The Wigner-Seitz pin-cell approximation has long been applied as a modeling approximation in analysis of UO2 lattice fuel cells. In the past, this approximation has been appropriate for such fuel. However, with increasing attention drawn to mixed-oxide (MOX) fuels with significant plutonium content, it is important to understand the implications of the approximation in a uranium-plutonium matrix. The special geometric capabilities of the deterministic NEWT computer code have been used to assess the adequacy of the Wigner-Seitz cell in such an environment, as part of a larger study of computational aspects of MOX fuel modeling. Results of calculations using various approximations and boundary conditions are presented, and are validated by comparison to results obtained using KENO V.a and XSDRNPM.