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Sample records for hungry axolotls ambystoma

  1. Terminal-Nerve-Derived Neuropeptide Y Modulates Physiological Responses in the Olfactory Epithelium of Hungry Axolotls (Ambystoma mexicanum)

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    Mousley, Angela; Polese, Gianluca; Marks, Nikki J.; Eisthen, Heather L.

    2007-01-01

    The vertebrate brain actively regulates incoming sensory information, effectively filtering input and focusing attention toward environmental stimuli that are most relevant to the animal's behavioral context or physiological state. Such centrifugal modulation has been shown to play an important role in processing in the retina and cochlea, but has received relatively little attention in olfaction. The terminal nerve, a cranial nerve that extends underneath the lamina propria surrounding the olfactory epithelium, displays anatomical and neurochemical characteristics that suggest that it modulates activity in the olfactory epithelium. Using immunocytochemical techniques, we demonstrate that neuropeptide Y (NPY) is abundantly present in the terminal nerve in the axolotl (Ambystoma mexicanum), an aquatic salamander. Because NPY plays an important role in regulating appetite and hunger in many vertebrates, we investigated the possibility that NPY modulates activity in the olfactory epithelium in relation to the animal's hunger level. We therefore characterized the full length NPY gene from axolotls to enable synthesis of authentic axolotl NPY for use in electrophysiological experiments. We find that axolotl NPY modulates olfactory epithelial responses evoked by L-glutamic acid, a food-related odorant, but only in hungry animals. Similarly, whole-cell patch-clamp recordings demonstrate that bath application of axolotl NPY enhances the magnitude of a tetrodotoxin-sensitive inward current, but only in hungry animals. These results suggest that expression or activity of NPY receptors in the olfactory epithelium may change with hunger level, and that terminal nerve-derived peptides modulate activity in the olfactory epithelium in response to an animal's changing behavioral and physiological circumstances. PMID:16855098

  2. Terminal nerve-derived neuropeptide y modulates physiological responses in the olfactory epithelium of hungry axolotls (Ambystoma mexicanum).

    Science.gov (United States)

    Mousley, Angela; Polese, Gianluca; Marks, Nikki J; Eisthen, Heather L

    2006-07-19

    The vertebrate brain actively regulates incoming sensory information, effectively filtering input and focusing attention toward environmental stimuli that are most relevant to the animal's behavioral context or physiological state. Such centrifugal modulation has been shown to play an important role in processing in the retina and cochlea, but has received relatively little attention in olfaction. The terminal nerve, a cranial nerve that extends underneath the lamina propria surrounding the olfactory epithelium, displays anatomical and neurochemical characteristics that suggest that it modulates activity in the olfactory epithelium. Using immunocytochemical techniques, we demonstrate that neuropeptide Y (NPY) is abundantly present in the terminal nerve in the axolotl (Ambystoma mexicanum), an aquatic salamander. Because NPY plays an important role in regulating appetite and hunger in many vertebrates, we investigated the possibility that NPY modulates activity in the olfactory epithelium in relation to the animal's hunger level. We therefore characterized the full-length NPY gene from axolotls to enable synthesis of authentic axolotl NPY for use in electrophysiological experiments. We find that axolotl NPY modulates olfactory epithelial responses evoked by l-glutamic acid, a food-related odorant, but only in hungry animals. Similarly, whole-cell patch-clamp recordings demonstrate that bath application of axolotl NPY enhances the magnitude of a tetrodotoxin-sensitive inward current, but only in hungry animals. These results suggest that expression or activity of NPY receptors in the olfactory epithelium may change with hunger level, and that terminal nerve-derived peptides modulate activity in the olfactory epithelium in response to an animal's changing behavioral and physiological circumstances.

  3. Transgenesis in axolotl (Ambystoma mexicanum).

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    Khattak, Shahryar; Tanaka, Elly M

    2015-01-01

    Transgenic animals have been indispensable in elucidating and deciphering mechanisms underlying various biological phenomena. In regeneration, transgenic animals expressing fluorescent protein genes have been crucial for identifying the source cells for regeneration and the mechanism of blastema formation. Animals are usually generated by manipulating their genome using various techniques at/in one cell embryo/fertilized egg stage. Here, we describe the generation of germline transgenic axolotls (Ambystoma mexicanum) using the I-SceI meganuclease and Tol2 transposase.

  4. Transcriptional landscapes of Axolotl (Ambystoma mexicanum).

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    Caballero-Pérez, Juan; Espinal-Centeno, Annie; Falcon, Francisco; García-Ortega, Luis F; Curiel-Quesada, Everardo; Cruz-Hernández, Andrés; Bako, Laszlo; Chen, Xuemei; Martínez, Octavio; Alberto Arteaga-Vázquez, Mario; Herrera-Estrella, Luis; Cruz-Ramírez, Alfredo

    2018-01-15

    The axolotl (Ambystoma mexicanum) is the vertebrate model system with the highest regeneration capacity. Experimental tools established over the past 100 years have been fundamental to start unraveling the cellular and molecular basis of tissue and limb regeneration. In the absence of a reference genome for the Axolotl, transcriptomic analysis become fundamental to understand the genetic basis of regeneration. Here we present one of the most diverse transcriptomic data sets for Axolotl by profiling coding and non-coding RNAs from diverse tissues. We reconstructed a population of 115,906 putative protein coding mRNAs as full ORFs (including isoforms). We also identified 352 conserved miRNAs and 297 novel putative mature miRNAs. Systematic enrichment analysis of gene expression allowed us to identify tissue-specific protein-coding transcripts. We also found putative novel and conserved microRNAs which potentially target mRNAs which are reported as important disease candidates in heart and liver. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Thyroxine-induced metamorphosis in the axolotl (Ambystoma mexicanum).

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    Coots, Peggy S; Seifert, Ashley W

    2015-01-01

    The axolotl (Ambystoma mexicanum) has remained an important model for regeneration and developmental biology for over a century. Although axolotls in captive-bred colonies usually exist in an aquatic form, they retain the ability to undergo metamorphosis following exposure to thyroid hormone. Here we present a robust method for inducing metamorphosis in adult axolotls that results in high survivability and produces terrestrial animals that can be maintained in long-term captivity.

  6. Resegmentation in the Mexican axolotl, Ambystoma mexicanum.

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    Piekarski, Nadine; Olsson, Lennart

    2014-02-01

    The segmental series of somites in the vertebrate embryo gives rise to the axial skeleton. In amniote models, single vertebrae are derived from the sclerotome of two adjacent somites. This process, known as resegmentation, is well-studied using the quail-chick chimeric system, but the presumed generality of resegmentation across vertebrates remains poorly evaluated. Resegmentation has been questioned in anamniotes, given that the sclerotome is much smaller and lacks obvious differentiation between cranial and caudal portions. Here, we provide the first experimental evidence that resegmentation does occur in a species of amphibian. Fate mapping of individual somites in the Mexican axolotl (Ambystoma mexicanum) revealed that individual vertebrae receive cells from two adjacent somites as in the chicken. These findings suggest that large size and segmentation of the sclerotome into distinct cranial and caudal portions are not requirements for resegmentation. Our results, in addition to those for zebrafish, indicate that resegmentation is a general process in building the vertebral column in vertebrates, although it may be achieved in different ways in different groups. Copyright © 2013 Wiley Periodicals, Inc.

  7. Housing and maintenance of Ambystoma mexicanum, the Mexican axolotl.

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    Farkas, Johanna E; Monaghan, James R

    2015-01-01

    The aim of this paper is to assemble a significant amount of information on Ambystoma mexicanum, the axolotl salamander, to assist in the basic knowledge needed to raise, breed, and study most aspects of axolotl biology. It is important to understand the basic biology of the axolotl in order to make informed decisions on their proper care and use in experiments. Therefore, we will provide necessary information to the non-herpetologist that will assist in their study of this unique and fascinating animal. We also aim to provide a resource on the general anatomy, behavior, and experimental tips specific to the Mexican axolotl that will be of use to most axolotl laboratories. Axolotls have been actively researched since the 1860s, giving testament to their relatively straightforward maintenance and their versatility as an animal model for development and regeneration. Interest in using the axolotl in laboratory research has grown tremendously over the past decade, so dedicated resources to support the study of this species are needed and encouraged.

  8. Pathological features of olfactory neuroblastoma in an axolotl (Ambystoma mexicanum).

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    Shioda, Chieko; Uchida, Kazuyuki; Nakayama, Hiroyuki

    2011-08-01

    A one-year-old, female Mexican axolotl (Ambystoma mexicanum) had a rough-surfaced, polypoid, pink tumor mass of approximately 10 mm in diameter in the oral cavity. Histologically, the tumor extended from the ethmoturbinate region and into the oral cavity and had replaced some of the maxillary bone tissue. The tumor mass was composed of a lobular architecture of small round-shaped tumor cells with occasional Flexner-Wintersteiner-like rosette formation. There were no metastatic lesions in the other organs. Immunohistochemically, the tumor cells were partly positive for several neural markers (class III beta-tubulin, S-100 protein, and doublecortin) and intensely positive for an epithelial marker (cytokeratin AE1/AE3). These results suggest that the present tumor originated from neuroectodermal tissue. Considering the location and histological and immunohistochemical features of the tumor, a diagnosis of olfactory neuroblastoma was made.

  9. Cutaneous mastocytomas in the neotenic caudate amphibians Ambystoma mexicanum (axolotl) and Ambystoma tigrinun (tiger salamander)

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    Harshbarger, J.C.; Chang, S.C.; DeLanney, L.E.; Rose, F.L.; Green, D.E.

    1999-01-01

    Spontaneous mastocytomas studied in 18 axolotls (Ambystoma mexicanum) and six tiger salamanders (Ambystoma tigrinum) were gray-white, uni- to multilobular cutaneous protrusions from 2mm to 2cm in diameter. Tumors were moderately cellular unencapsulated masses that usually infiltrated the dermis and hypodermis with the destruction of intervening tissues. Some tumors were invading superficial bundles of the underlying skeletal muscle. Tumors consisted of mitotically active cells derived from a single lineage but showing a range of differentiation. Immature cells had nearly smooth to lightly cleft or folded basophilic nuclei bordered by a band of cytoplasm with few cytoplasmic processes and containing a few small uniform eccentric granules. Mature cells had basophilic nuclei with deep clefts or folds and abundant eosinophilic cytoplasm with multiple long intertwining cytoplasmic extensions packed with metachromatic granules. The axolotls were old individuals from an inbred laboratory colony. The tiger salamanders were wild animals from a single polluted pond. They could have been old and inbred. Both groups were neotenic. These are the first mastocytomas discovered in cold-blooded animals.

  10. Evidence for balancing selection at the DAB locus in the axolotl, Ambystoma mexicanum.

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    Richman, A D; Herrera, G; Reynoso, V H; Méndez, G; Zambrano, L

    2007-12-01

    The axolotl (Ambystoma mexicanum) has been characterized as immunodeficient, and the absence of major histocompatibility complex (MHC) class II polymorphism has been cited as a possible explanation. Here we present evidence for considerable allelic polymorphism at the MHC class II DAB locus for a sample of wild-caught axolotls. Evidence that these sequences are the product of balancing selection for disease resistance is discussed.

  11. An introduction to the Mexican axolotl (Ambystoma mexicanum).

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    Gresens, Jill

    2004-10-01

    A number of unusual traits, including a remarkable capacity for wound healing and limb regeneration, make the axolotl an interesting animal model. The author provides an overview of axolotl care and use in biomedical research.

  12. Identification of reference genes and validation for gene expression studies in diverse axolotl (Ambystoma mexicanum) tissues.

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    Guelke, Eileen; Bucan, Vesna; Liebsch, Christina; Lazaridis, Andrea; Radtke, Christine; Vogt, Peter M; Reimers, Kerstin

    2015-04-10

    For the precise quantitative RT-PCR normalization a set of valid reference genes is obligatory. Moreover have to be taken into concern the experimental conditions as they bias the regulation of reference genes. Up till now, no reference targets have been described for the axolotl (Ambystoma mexicanum). In a search in the public database SalSite for genetic information of the axolotl we identified fourteen presumptive reference genes, eleven of which were further tested for their gene expression stability. This study characterizes the expressional patterns of 11 putative endogenous control genes during axolotl limb regeneration and in an axolotl tissue panel. All 11 reference genes showed variable expression. Strikingly, ACTB was to be found most stable expressed in all comparative tissue groups, so we reason it to be suitable for all different kinds of axolotl tissue-type investigations. Moreover do we suggest GAPDH and RPLP0 as suitable for certain axolotl tissue analysis. When it comes to axolotl limb regeneration, a validated pair of reference genes is ODC and RPLP0. With these findings, new insights into axolotl gene expression profiling might be gained. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Misexpression experiment of Tbx5 in axolotl (Ambystoma mexicanum) hindlimb blastema.

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    Shimokawa, Takashi; Kominami, Rieko; Yasutaka, Satoru; Shinohara, Harumichi

    2013-01-01

    Axolotls (Ambystoma mexicanum) have the ability to regenerate amputated limbs throughout their life span. In the present study, we attempted to elucidate how axolotls can specify limb type correctly during the regeneration process. We misexpressed Tbx5 in regenerating hindlimb blastema, and consequently a forelimb-like hindlimb regenerated from the hindlimb blastema. On the other hand, no change was observed in Tbx5-overexpressing forelimb blastema, and thus we considered that Tbx5 plays a key role in the specification of forelimb during the regeneration process of axolotl limbs. However, axolotls' fore- and hindlimbs have very similar structures except for the number of fingers, and it was very difficult to judge whether the forelimb-like regenerate was a true forelimb or merely a forelimb-like hindlimb. Therefore, in order to confirm our conclusion, we have to investigate other genes that are expressed differentially between fore- and hindlimbs in future experiments.

  14. The axolotl (Ambystoma mexicanum), a neotenic amphibian, expresses functional thyroid hormone receptors.

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    Safi, Rachid; Bertrand, Stéphanie; Marchand, Oriane; Duffraisse, Marilyne; de Luze, Amaury; Vanacker, Jean-Marc; Maraninchi, Marie; Margotat, Alain; Demeneix, Barbara; Laudet, Vincent

    2004-02-01

    Neotenic amphibians such as the axolotl (Ambystoma mexicanum) are often unable to undergo metamorphosis under natural conditions. It is thought that neoteny represents a deviation from the standard course of amphibian ontogeny, affecting the thyroid axis at different levels from the central nervous system to peripheral organs. Thyroid hormone receptors (TRs) that bind the thyroid hormone (TH) T(3) have been described in axolotl. However, the full sequences of TR were needed to better characterize the TH response and to be able to assess their functional capacity at the molecular level. We report that each of the alpha and beta axolotl TRs bind both DNA and TH, and they activate transcription in response to TH in a mammalian cell-based transient transfection assay. Moreover, both TRs are expressed in axolotl tissues. Interestingly, each TR gene generates alternatively spliced isoforms, harboring partial or total deletions of the ligand-binding domain, which are expressed in vivo. Further, we found that in the axolotl, TH regulates the expression of stromelysin 3 and collagenase 3, which are TH target genes in Xenopus. Taken together, these results suggest that axolotl TRs are functional and that the molecular basis of neoteny in the axolotl is not linked to a major defect in TH response in peripheral tissues.

  15. Forever young: Endocrinology of paedomorphosis in the Mexican axolotl (Ambystoma mexicanum).

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    De Groef, Bert; Grommen, Sylvia V H; Darras, Veerle M

    2018-05-16

    The Mexican axolotl (Ambystoma mexicanum) is a salamander species that does not undergo metamorphosis, resulting in the retention of juvenile characteristics in the mature breeding stage (paedomorphosis). Here we review the endocrinological studies investigating the proximate cause of axolotl paedomorphosis with a focus on the hypothalamo-pituitary-thyroid (HPT) axis. It is well established that axolotl paedomorphosis is a consequence of low activity of the HPT axis. The pituitary hormone thyrotropin (TSH) is capable of inducing metamorphosis in the axolotl, which indicates that all processes and interactions in the HPT axis below the pituitary level are functional, but that TSH release is impaired. In metamorphosing species, TSH secretion is largely controlled by the hypothalamic neuropeptide corticotropin-releasing hormone (CRH), which seems to have lost its thyrotropic activity in the axolotl. However, preliminary experiments have not yet confirmed a role for faulty CRH signalling in axolotl paedomorphosis. Other hypothalamic factors and potential pituitary inhibitors need to be investigated to identify their roles in amphibian metamorphosis and axolotl paedomorphosis. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Evolutionary genetics of metamorphic failure using wild-caught vs. laboratory axolotls (Ambystoma mexicanum).

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    Voss, S R; Shaffer, H B

    2000-09-01

    In many organisms metamorphosis allows for an ecologically important habitat-shift from water to land. However, in some salamanders an adaptive life cycle mode has evolved that is characterized by metamorphic failure (paedomorphosis); these species remain in the aquatic habitat throughout the life cycle. Perhaps the most famous example of metamorphic failure is the Mexican axolotl (Ambystoma mexicanum), which has become a focal species for developmental biology since it was introduced into laboratory culture in the 1800s. Our previous genetic linkage mapping analysis, using an interspecific crossing design, demonstrated that a major gene effect underlies the expression of metamorphic failure in laboratory stocks of the Mexican axolotl. Here, we repeated this experiment using A. mexicanum that were sampled directly from their natural habitat at Lake Xochimilco, Mexico. We found no significant association between the major gene and metamorphic failure when wild-caught axolotls were used in the experimental design, although there is evidence of a smaller genetic effect. Thus, there appears to be genetic variation among Mexican axolotls (and possibly A. tigrinum tigrinum) at loci that contribute to metamorphic failure. This result suggests a role for more than one mutation and possibly artificial selection in the evolution of the major gene effect in the laboratory Mexican axolotl.

  17. Optimized axolotl (Ambystoma mexicanum) husbandry, breeding, metamorphosis, transgenesis and tamoxifen-mediated recombination.

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    Khattak, Shahryar; Murawala, Prayag; Andreas, Heino; Kappert, Verena; Schuez, Maritta; Sandoval-Guzmán, Tatiana; Crawford, Karen; Tanaka, Elly M

    2014-03-01

    The axolotl (Mexican salamander, Ambystoma mexicanum) has become a very useful model organism for studying limb and spinal cord regeneration because of its high regenerative capacity. Here we present a protocol for successfully mating and breeding axolotls in the laboratory throughout the year, for metamorphosing axolotls by a single i.p. injection and for axolotl transgenesis using I-SceI meganuclease and the mini Tol2 transposon system. Tol2-mediated transgenesis provides different features and advantages compared with I-SceI-mediated transgenesis, and it can result in more than 30% of animals expressing the transgene throughout their bodies so that they can be directly used for experimentation. By using Tol2-mediated transgenesis, experiments can be performed within weeks (e.g., 5-6 weeks for obtaining 2-3-cm-long larvae) without the need to establish germline transgenic lines (which take 12-18 months). In addition, we describe here tamoxifen-induced Cre-mediated recombination in transgenic axolotls.

  18. Proteinaceous Pheromone Homologs Identified from the Cloacal Gland Transcriptome of a Male Axolotl, Ambystoma mexicanum.

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    Kevin W Hall

    Full Text Available Pheromones play an important role in modifying vertebrate behavior, especially during courtship and mating. Courtship behavior in urodele amphibians often includes female exposure to secretions from the cloacal gland, as well as other scent glands. The first vertebrate proteinaceous pheromone discovered, the decapeptide sodefrin, is a female attracting pheromone secreted by the cloacal gland of male Cynops pyrrhogaster. Other proteinaceous pheromones in salamanders have been shown to elicit responses from females towards conspecific males. The presence and levels of expression of proteinaceous pheromones have not been identified in the family Ambystomatidae, which includes several important research models. The objective of this research was therefore to identify putative proteinaceous pheromones from male axolotls, Ambystoma mexicanum, as well as their relative expression levels. The results indicate that axolotls possess two different forms of sodefrin precursor-like factor (alpha and beta, as well as a putative ortholog of plethodontid modulating factor. The beta form of sodefrin precursor-like factor was amongst the most highly expressed transcripts within the cloacal gland. The ortholog of plethodontid modulating factor was expressed at a level equivalent to the beta sodefrin precursor-like factor. The results are from a single male axolotl; therefore, we are unable to assess how representative our results may be. Nevertheless, the presence of these highly expressed proteinaceous pheromones suggests that male axolotls use multiple chemical cues to attract female conspecifics. Behavioral assays would indicate whether the putative protein pheromones elicit courtship activity from female axolotls.

  19. Proteinaceous Pheromone Homologs Identified from the Cloacal Gland Transcriptome of a Male Axolotl, Ambystoma mexicanum.

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    Hall, Kevin W; Eisthen, Heather L; Williams, Barry L

    2016-01-01

    Pheromones play an important role in modifying vertebrate behavior, especially during courtship and mating. Courtship behavior in urodele amphibians often includes female exposure to secretions from the cloacal gland, as well as other scent glands. The first vertebrate proteinaceous pheromone discovered, the decapeptide sodefrin, is a female attracting pheromone secreted by the cloacal gland of male Cynops pyrrhogaster. Other proteinaceous pheromones in salamanders have been shown to elicit responses from females towards conspecific males. The presence and levels of expression of proteinaceous pheromones have not been identified in the family Ambystomatidae, which includes several important research models. The objective of this research was therefore to identify putative proteinaceous pheromones from male axolotls, Ambystoma mexicanum, as well as their relative expression levels. The results indicate that axolotls possess two different forms of sodefrin precursor-like factor (alpha and beta), as well as a putative ortholog of plethodontid modulating factor. The beta form of sodefrin precursor-like factor was amongst the most highly expressed transcripts within the cloacal gland. The ortholog of plethodontid modulating factor was expressed at a level equivalent to the beta sodefrin precursor-like factor. The results are from a single male axolotl; therefore, we are unable to assess how representative our results may be. Nevertheless, the presence of these highly expressed proteinaceous pheromones suggests that male axolotls use multiple chemical cues to attract female conspecifics. Behavioral assays would indicate whether the putative protein pheromones elicit courtship activity from female axolotls.

  20. Ambiguities in the relationship between gonadal steroids and reproduction in axolotls (Ambystoma mexicanum).

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    Eisthen, Heather L; Krause, Brianne Chung

    2012-05-01

    Axolotls (Ambystoma mexicanum) are aquatic salamanders that are widely used in research. Axolotls have been bred in laboratories for nearly 150 years, yet little is known about the basic biology of reproduction in these animals. We investigated the effects of changing day length, time of year, and food availability on levels of circulating estradiol and androgens in adult female and male axolotls, respectively. In addition, we examined the effects of these variables on the mass of ovaries, oviducts, and eggs in females and on mass of testes in males relative to each individual's body weight, to calculate a form of gonadosomatic index (GSI). In both sexes, GSI was not correlated with levels of circulating steroids. In female axolotls, estradiol levels were influenced by food availability, changes in day length, and season, even when animals were held at a constant temperature and day length was decorrelated with calendar date. In addition, the mass of ovaries, oviducts, and eggs varied seasonally, peaking in the winter months and declining during the summer months, even though our animals were not breeding and shedding eggs. In males, levels of androgens appeared to vary independently of external conditions, but GSI varied dramatically with changes in day length. These results suggest that reproduction in axolotls may vary seasonally, as it does in many other ambystomid species, although both male and female axolotls are capable of reproducing several times each year. The physiological basis of this ability remains enigmatic, given the indications of seasonality contained in our data. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Organophosphorus pesticides effect on early stages of the axolotl Ambystoma mexicanum (Amphibia: Caudata).

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    Robles-Mendoza, C; García-Basilio, C; Cram-Heydrich, S; Hernández-Quiroz, M; Vanegas-Pérez, C

    2009-02-01

    Ambystoma mexicanum is an endemic salamander of Xochimilco, a wetland of the basin of Mexico valley. Nowadays, axolotl populations are decreasing due environmental stressors. Particularly, studies about organophosphorus pesticides (OPPs; i.e. chlorpyrifos and malathion) toxicity are of great importance due to their intensive use in agricultural activities in Xochimilco. Thus, the aim of this study was to evaluate under controlled conditions the toxicity of chlorpyrifos (CPF) and malathion (MLT) on embryos and larvae (stage 44 and 54) of A. mexicanum. Embryos and larvae were exposure 96h from 0.5 to 3mg CPFL(-1) and from 10 to 30mg MLTL(-1) in independent tests. Embryos at the end of this period were maintained 9d without pesticide in order to identify possible recuperation. Differences obtained in mortality, hatching success, development, morphological abnormalities, behaviour and activity, suggest that toxicity of CPF and MLT differs in embryos and larval stages. Embryos were less sensitive to OPPs acute exposure than axolotl larvae; additionally, toxicity of CPF in larval stages was greater than MLT. On the other hand, data obtained in axolotl embryos during the period of recuperation to CPF in particular as delay and inhibition of development, malformations and success of hatching, indicated that these responses turned out more sensitive than mortality. This study allowed to identify the toxicological potential of OPPs on early developmental stages of A. mexicanum and it is a valuable contribution for the future management of the axolotl wild population.

  2. Gallium nitrate: effects on cartilage during limb regeneration in the axolotl, Ambystoma mexicanum.

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    Tassava, Roy A; Mendenhall, Luciara; Apseloff, Glen; Gerber, Nicholas

    2002-09-01

    Gallium nitrate, a drug shown to have efficacy in Paget's disease of bone, hypercalcemia of malignancy, and a variety of experimental autoimmune diseases, also inhibits the growth of some types of cancer. We examined dose and timing of administration of gallium nitrate on limb regeneration in the Mexican axolotl, Ambystoma mexicanum. Administered by intraperitoneal injection, gallium nitrate inhibited limb regeneration in a dose-dependent manner. Gallium nitrate initially suppressed epithelial wound healing and subsequently distorted both anterior-posterior and proximo-distal chondrogenic patterns. Gallium nitrate given at three days after amputation severely inhibited regeneration at high doses (6.25 mg/axolotl) and altered the normal patterning of the regenerates at low doses (3.75 mg/axolotl). Administration of 6.25 mg of gallium nitrate at four or 14 days prior to amputation also inhibited regeneration. In amputated limbs of gallium-treated axolotls, the chondrocytes were lost from inside the radius/ulna. Limbs that regenerated after gallium treatment was terminated showed blastema formation preferentially over the ulna. New cartilage of the regenerate often attached to the sides of the existing radius/ulna proximally into the stump and less so to the distal cut ends. J. Exp. Zool. 293:384-394, 2002. Copyright 2002 Wiley-Liss, Inc.

  3. Courtship Pheromone Use in a Model Urodele, the Mexican Axolotl (Ambystoma mexicanum).

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    Maex, Margo; Van Bocxlaer, Ines; Mortier, Anneleen; Proost, Paul; Bossuyt, Franky

    2016-02-04

    Sex pheromones have been shown to constitute a crucial aspect of salamander reproduction. Until now, courtship pheromones of Salamandridae and Plethodontidae have been intensively studied, but information on chemical communication in other urodelan families is essentially lacking. The axolotl (Ambystoma mexicanum, Ambystomatidae) has a courtship display that suggests a key role for chemical communication in the orchestration of its sexual behavior, but no sex pheromones have yet been characterized from this species. Here we combined whole transcriptome analyses of the male cloaca with proteomic analyses of water in which axolotls were allowed to court to show that male axolotls secrete multiple ca. 20 kDa glycosylated sodefrin precursor-like factor (SPF) proteins during courtship. In combination with phylogenetic analyses, our data show that the male cloaca essentially secretes a courtship-specific clade of SPF proteins that is orthologous to salamandrid courtship pheromones. In addition, we identified an SPF protein for which no orthologs have been described from other salamanders so far. Overall, our study advocates a central role for SPF proteins during the courtship display of axolotls and adds knowledge on pheromone use in a previously unexplored deep evolutionary branch of salamander evolution.

  4. Evaluation of the anesthetic effects of MS222 in the adult Mexican axolotl (Ambystoma mexicanum

    Directory of Open Access Journals (Sweden)

    Zullian C

    2016-01-01

    Full Text Available Chiara Zullian,1 Aurore Dodelet-Devillers,1 Stéphane Roy,2 Pascal Vachon1 1Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, 2Département de Stomatologie, Faculté de Médecine Dentaire, Montréal, Québec, Canada Abstract: The Mexican axolotl (Ambystoma mexicanum is a unique research model in several fields of medicine, where surgical and invasive procedures may be required. As yet, little is known about the efficacy of MS222 (tricaine methanesulfonate, which is the most commonly used anesthetic agent in amphibians. The main objectives of this study were to evaluate the anesthetic effects and physiological changes in adult axolotls following a 20-minute immersion bath, containing progressive MS222 concentrations starting at 0.1%. Depth of anesthesia and physiological changes were evaluated every 15 minutes post-MS222 exposure with the following parameters: righting behavior, withdrawal reflex, acetic acid test response, heart rate, and blood oxygen saturation, as well as cloacal and body surface temperatures. A 20-minute exposure in a 0.1% MS222 immersion bath (n=6 animals had no anesthetic effects on adult axolotls after 20 minutes of exposure. With a 0.2% MS222 solution, all axolotls (n=9 were deeply anesthetized at 15 minutes, and 80% were still unresponsive at 30 minutes postexposure. Blood oxygen saturation and heart rate were slightly, but significantly, increased when compared with the baseline value and remained stable up to recovery. There was no significant increase in surface and cloaca temperatures, compared with baseline. With the 0.4% MS222 solution, the duration of anesthesia lasted for 90 minutes to at least 120 minutes (n=3 animals and this concentration was deemed too high. In conclusion, a 20-minute immersion bath with 0.2% MS222 may be used for short procedures (15–30 minutes requiring anesthesia of adult axolotls. Keywords: Ambystoma mexicanum

  5. Esterases activity in the axolotl Ambystoma mexicanum exposed to chlorpyrifos and its implication to motor activity.

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    Robles-Mendoza, Cecilia; Zúñiga-Lagunes, Sebastian R; Ponce de León-Hill, Claudia A; Hernández-Soto, Jesús; Vanegas-Pérez, Cecilia

    2011-10-01

    The axolotl Ambystoma mexicanum is a neotenic salamander considered a good biological model due to its ability to regenerate limbs, tail, brain and heart cells. Nevertheless, severe reduction of A. mexicanum wild populations in the lacustrine area of Xochimilco, the natural habitat of the axolotl, could be related to several environmental pressures as the presence of organophosphate pesticides (OPPs), intensively applied in agricultural activities in Xochimilco. Thus the aim of this study was to evaluate the effect of environmentally realistic chlorpyrifos (CPF) concentrations, a OPP commonly used in this zone, on esterases activity (acetylcholinesterase and carboxylesterase) and bioconcentration of CPF and to relate them with the motor activity of A. mexicanum juveniles. Axolotls were exposed 48 h to 0.05 and 0.1mg CPF/L, and the responses were evaluated at the end of the CPF exposure. Results suggest that CPF is bioconcentrated into axolotls and that the CPF internal concentrations are related with the observed inhibition activity of AChE (>50%) and CbE (≈ 50%). CPF concentration responsible of the inhibition of the 50% of AChE activity (IC50) was estimated in 0.04 mg CPF/L; however IC50 for CbE activity was not possible to calculate since inhibition levels were lower than 50%, results that suggest a higher resistance of CbE enzymatic activity to CPF. However, motor activity was a more sensitive endpoint to CPF poisoning since time that axolotls spent active and walking, frequency and speed of swimming, frequency of prey attack were reduced >90% of control groups. The motor activity alterations in the axolotl could be related with the registered esterases inhibition. Thus important alterations on axolotls were identified even at short time and low concentrations of CPF exposure. Also, it was possible to link biochemical responses as esterases activity with higher levels of biological organization as behavior. This study provides tools for the regulation of the

  6. Regeneration of limb joints in the axolotl (Ambystoma mexicanum).

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    Lee, Jangwoo; Gardiner, David M

    2012-01-01

    In spite of numerous investigations of regenerating salamander limbs, little attention has been paid to the details of how joints are reformed. An understanding of the process and mechanisms of joint regeneration in this model system for tetrapod limb regeneration would provide insights into developing novel therapies for inducing joint regeneration in humans. To this end, we have used the axolotl (Mexican Salamander) model of limb regeneration to describe the morphology and the expression patterns of marker genes during joint regeneration in response to limb amputation. These data are consistent with the hypothesis that the mechanisms of joint formation whether it be development or regeneration are conserved. We also have determined that defects in the epiphyseal region of both forelimbs and hind limbs in the axolotl are regenerated only when the defect is small. As is the case with defects in the diaphysis, there is a critical size above which the endogenous regenerative response is not sufficient to regenerate the joint. This non-regenerative response in an animal that has the ability to regenerate perfectly provides the opportunity to screen for the signaling pathways to induce regeneration of articular cartilage and joints.

  7. Regeneration of limb joints in the axolotl (Ambystoma mexicanum.

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    Jangwoo Lee

    Full Text Available In spite of numerous investigations of regenerating salamander limbs, little attention has been paid to the details of how joints are reformed. An understanding of the process and mechanisms of joint regeneration in this model system for tetrapod limb regeneration would provide insights into developing novel therapies for inducing joint regeneration in humans. To this end, we have used the axolotl (Mexican Salamander model of limb regeneration to describe the morphology and the expression patterns of marker genes during joint regeneration in response to limb amputation. These data are consistent with the hypothesis that the mechanisms of joint formation whether it be development or regeneration are conserved. We also have determined that defects in the epiphyseal region of both forelimbs and hind limbs in the axolotl are regenerated only when the defect is small. As is the case with defects in the diaphysis, there is a critical size above which the endogenous regenerative response is not sufficient to regenerate the joint. This non-regenerative response in an animal that has the ability to regenerate perfectly provides the opportunity to screen for the signaling pathways to induce regeneration of articular cartilage and joints.

  8. Probability of Regenerating a Normal Limb After Bite Injury in the Mexican Axolotl (Ambystoma mexicanum).

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    Thompson, Sierra; Muzinic, Laura; Muzinic, Christopher; Niemiller, Matthew L; Voss, S Randal

    2014-06-01

    Multiple factors are thought to cause limb abnormalities in amphibian populations by altering processes of limb development and regeneration. We examined adult and juvenile axolotls ( Ambystoma mexicanum ) in the Ambystoma Genetic Stock Center (AGSC) for limb and digit abnormalities to investigate the probability of normal regeneration after bite injury. We observed that 80% of larval salamanders show evidence of bite injury at the time of transition from group housing to solitary housing. Among 717 adult axolotls that were surveyed, which included solitary-housed males and group-housed females, approximately half presented abnormalities, including examples of extra or missing digits and limbs, fused digits, and digits growing from atypical anatomical positions. Bite injury likely explains these limb defects, and not abnormal development, because limbs with normal anatomy regenerated after performing rostral amputations. We infer that only 43% of AGSC larvae will present four anatomically normal looking adult limbs after incurring a bite injury. Our results show regeneration of normal limb anatomy to be less than perfect after bite injury.

  9. Linking vertebral number to performance of aquatic escape responses in the axolotl (Ambystoma mexicanum).

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    Ackerly, Kerri L; Ward, Andrea B

    2015-12-01

    Environmental conditions during early development in ectothermic vertebrates can lead to variation in vertebral number among individuals of the same species. It is often seen that individuals of a species raised at cooler temperatures have more vertebrae than individuals raised at warmer temperatures, although the functional consequences of this variation in vertebral number on swimming performance are relatively unclear. To investigate this relationship, we tested how vertebral number in axolotls (Ambystoma mexicanum) affected performance of aquatic escape responses (C-starts). Axolotls were reared at four temperatures (12-24°C) encompassing their natural thermal range and then transitioned to a mean temperature (18°C) three months before C-starts were recorded. Our results showed variation in vertebral number, but that variation was not significantly affected by developmental temperature. C-start performance among axolotls was significantly correlated with caudal vertebral number, and individuals with more caudal vertebrae were able to achieve greater curvature more quickly during their responses than individuals with fewer vertebrae. However, our results show that these individuals did not achieve greater displacements or velocities, and that developmental temperature did not have any effect on C-start performance. We highlight that the most important aspects of escape swim performance (i.e., how far individuals get from a threat and how quickly they move the most important parts of the body away from that threat) are consistent across individuals regardless of developmental temperature and morphological variation. Copyright © 2015 Elsevier GmbH. All rights reserved.

  10. Buoyancy disorders in pet axolotls Ambystoma mexicanum: three cases.

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    Takami, Yoshinori; Une, Yumi

    2018-01-31

    As far as we are aware, there are no previous reports on the pathologic conditions of buoyancy disorders in Ambystoma mexicanum. Herein, we describe various clinical test results, clinical outcomes, and the pathological findings of an experimental pneumonectomy procedure in 3 A. mexicanum exhibiting abnormal buoyancy. The 3 pet A. mexicanum were adults, and their respective ages and body weights were 1, 5, and 6 yr and 48, 55, and 56 g. Two of these cases were confirmed via radiographic examination to have free air within the body cavity, and all 3 cases were found via ultrasonography to have an acoustic shadow within the body cavity and were diagnosed with pneumocoelom. Lung perforations were detected macroscopically in 2 of the cases, and all 3 cases had fibrosis in the caudal ends of the lungs. Removal of the lung lesions eliminated the abnormal buoyancy in all 3 cases. We concluded that air had leaked into the body cavity from the lungs, and we propose that lung lesions are an important cause of buoyancy disorders in A. mexicanum.

  11. Neural crest does not contribute to the neck and shoulder in the axolotl (Ambystoma mexicanum).

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    Epperlein, Hans-Henning; Khattak, Shahryar; Knapp, Dunja; Tanaka, Elly M; Malashichev, Yegor B

    2012-01-01

    A major step during the evolution of tetrapods was their transition from water to land. This process involved the reduction or complete loss of the dermal bones that made up connections to the skull and a concomitant enlargement of the endochondral shoulder girdle. In the mouse the latter is derived from three separate embryonic sources: lateral plate mesoderm, somites, and neural crest. The neural crest was suggested to sustain the muscle attachments. How this complex composition of the endochondral shoulder girdle arose during evolution and whether it is shared by all tetrapods is unknown. Salamanders that lack dermal bone within their shoulder girdle were of special interest for a possible contribution of the neural crest to the endochondral elements and muscle attachment sites, and we therefore studied them in this context. We grafted neural crest from GFP+ fluorescent transgenic axolotl (Ambystoma mexicanum) donor embryos into white (d/d) axolotl hosts and followed the presence of neural crest cells within the cartilage of the shoulder girdle and the connective tissue of muscle attachment sites of the neck-shoulder region. Strikingly, neural crest cells did not contribute to any part of the endochondral shoulder girdle or to the connective tissue at muscle attachment sites in axolotl. Our results in axolotl suggest that neural crest does not serve a general function in vertebrate shoulder muscle attachment sites as predicted by the "muscle scaffold theory," and that it is not necessary to maintain connectivity of the endochondral shoulder girdle to the skull. Our data support the possibility that the contribution of the neural crest to the endochondral shoulder girdle, which is observed in the mouse, arose de novo in mammals as a developmental basis for their skeletal synapomorphies. This further supports the hypothesis of an increased neural crest diversification during vertebrate evolution.

  12. Neural crest does not contribute to the neck and shoulder in the axolotl (Ambystoma mexicanum.

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    Hans-Henning Epperlein

    Full Text Available BACKGROUND: A major step during the evolution of tetrapods was their transition from water to land. This process involved the reduction or complete loss of the dermal bones that made up connections to the skull and a concomitant enlargement of the endochondral shoulder girdle. In the mouse the latter is derived from three separate embryonic sources: lateral plate mesoderm, somites, and neural crest. The neural crest was suggested to sustain the muscle attachments. How this complex composition of the endochondral shoulder girdle arose during evolution and whether it is shared by all tetrapods is unknown. Salamanders that lack dermal bone within their shoulder girdle were of special interest for a possible contribution of the neural crest to the endochondral elements and muscle attachment sites, and we therefore studied them in this context. RESULTS: We grafted neural crest from GFP+ fluorescent transgenic axolotl (Ambystoma mexicanum donor embryos into white (d/d axolotl hosts and followed the presence of neural crest cells within the cartilage of the shoulder girdle and the connective tissue of muscle attachment sites of the neck-shoulder region. Strikingly, neural crest cells did not contribute to any part of the endochondral shoulder girdle or to the connective tissue at muscle attachment sites in axolotl. CONCLUSIONS: Our results in axolotl suggest that neural crest does not serve a general function in vertebrate shoulder muscle attachment sites as predicted by the "muscle scaffold theory," and that it is not necessary to maintain connectivity of the endochondral shoulder girdle to the skull. Our data support the possibility that the contribution of the neural crest to the endochondral shoulder girdle, which is observed in the mouse, arose de novo in mammals as a developmental basis for their skeletal synapomorphies. This further supports the hypothesis of an increased neural crest diversification during vertebrate evolution.

  13. Ultrastructure of the external gill epithelium of the axolotl, Ambystoma mexicanum with reference to ionic transport.

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    Jarial, M S; Wilkins, J H

    2003-10-01

    The ultrastructure of the external gill epithelium of the axolotl, Ambystoma mexicanum, has been examined using conventional transmission electron microscopy to elucidate its role in ionic transport. Four cell types are identified in the gill filament and primary gill bar epithelium. These are granular, ciliated, Leydig and basal cells. A fifth cell type, the flat mitochondria-rich cell is only found in the gill bar epithelium. The predominant granular cells display microvilli at their surface and their cytoplasm contains abundant mitochondria, rough endoplasmic reticulum, Golgi complexes, vesicles and PAS+ secretory granules that are extruded at the surface, which along with secretions from the Leydig cells form a mucous coat. The granular cells are joined apically by junctional complexes consisting of zonulae occludens, zonulae adherens and desmosomes. The lateral membranes of granular cells enclose large intercellular spaces that are closed at the apical ends but remain open at the basal ends adjoining capillaries. In AgNO3-treated axolotl, the gills become darkly stained, the silver grains penetrate apical membranes and appear in the cytoplasm, accumulating near the lateral membranes and also enter the intercellular spaces. These findings are consistent with the dual role of the gill epithelium in mucus production and active ionic transport.

  14. Excretory nitrogen metabolism in the juvenile axolotl Ambystoma mexicanum: differences in aquatic and terrestrial environments.

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    Loong, Ai M; Chew, Shit F; Ip, Yuen K

    2002-01-01

    The fully grown but nonmetamorphosed (juvenile) axolotl Ambystoma mexicanum was ureogenic and primarily ureotelic in water. A complete ornithine-urea cycle (OUC) was present in the liver. Aerial exposure impeded urea (but not ammonia) excretion, leading to a decrease in the percentage of nitrogen excreted as urea in the first 24 h. However, urea and not ammonia accumulated in the muscle, liver, and plasma during aerial exposure. By 48 h, the rate of urea excretion recovered fully, probably due to the greater urea concentration gradient in the kidney. It is generally accepted that an increase in carbamoyl phosphate synthetase activity is especially critical in the developmental transition from ammonotelism to ureotelism in the amphibian. Results from this study indicate that such a transition in A. mexicanum would have occurred before migration to land. Aerial exposure for 72 h exhibited no significant effect on carbamoyl phosphate synthetase-I activity or that of other OUC enzymes (with the exception of ornithine transcarbamoylase) from the liver of the juvenile A. mexicanum. This supports our hypothesis that the capacities of OUC enzymes present in the liver of the aquatic juvenile axolotl were adequate to prepare it for its invasion of the terrestrial environment. The high OUC capacity was further supported by the capability of the juvenile A. mexicanum to survive in 10 mM NH(4)Cl without accumulating amino acids in its body. The majority of the accumulating endogenous and exogenous ammonia was detoxified to urea, which led to a greater than twofold increase in urea levels in the muscle, liver, and plasma and a significant increase in urea excretion by hour 96. Hence, it can be concluded that the juvenile axolotl acquired ureotelism while submerged in water, and its hepatic capacity of urea synthesis was more than adequate to handle the toxicity of endogenous ammonia during migration to land.

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

    Science.gov (United States)

    Hanner, R H; Ryan, G B

    1980-01-01

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

  16. Highly restricted diversity of TCR delta chains of the amphibian Mexican axolotl (Ambystoma mexicanum) in peripheral tissues.

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    André, Sébastien; Kerfourn, Fabienne; Affaticati, Pierre; Guerci, Aline; Ravassard, Philippe; Fellah, Julien S

    2007-06-01

    Gammadelta T cells localize at mammalian epithelial surfaces to exert both protective and regulatory roles in response to infections. We have previously characterized the Mexican axolotl (Ambystoma mexicanum) T cell receptor delta (TRD) chain. In this study, TRD repertoires in spleen, liver, intestine and skin from larvae, pre-adult and adult axolotls were examined and compared to the thymic TRD repertoire. A TRDV transcript without N/D diversity, TRDV1S1-TRDJ1, dominates the TRD repertoires until sexual maturation. In adult tissues, this canonical transcript is replaced by another dominant TRDV1S1-TRDJ1 transcript. In the thymus, these two transcripts are detected early in development. Our results suggest that gammadelta T cells that express the canonical TRDV1S1-TRDJ1 transcript emerge from the thymus and colonize the peripheral tissues, where they are selectively expanded by recurrent ligands. This particular situation is probably related to the neotenic state and the slow development of the axolotl. In thymectomized axolotls, TRD repertoires appear different from those of normal axolotls, suggesting that extrathymic gammadelta T cell differentiation could occur. Gene expression analysis showed the importance of the gut in T cell development.

  17. Collection of gametes from live axolotl, Ambystoma mexicanum, and standardization of in vitro fertilization.

    Science.gov (United States)

    Mansour, N; Lahnsteiner, F; Patzner, R A

    2011-01-15

    This study established the first protocol for collection of gametes from live axolotl, Ambystoma mexicanum, by gentle abdominal massage and in vitro fertilization. To stimulate spermiation and ovulation, human chorionic gonadotrophin (hCG) and Ovopel pellets, which are commercially used to stimulate spawning in fish, were tested. The hCG was more effective than Ovopel pellets and yielded a higher semen volume in the injected males and a shorter response time in the females. Collected semen by this method was already motile and fertile. Fertile eggs could be collected in 3-4 successive collection times after the female has started the typical spawning behaviour. The fertilization condition that yielded the highest hatching rate was mixing semen with eggs before the addition of a fertilization saline solution (20 mmol/l NaCl, 1 mmol/l KCl, 1 mmol/l Mg(2)SO(4), 1 mmol Ca(2)Cl, 3 mmol NaHCO(3), 10 mmol/l Tris, pH 8.5 - Osmolality = 65 mosmol/kg). When the pH of the fertilization solution was increased to ≥ 10, the hatching rate was significantly increased. The use of fertilization solutions with osmolalities of ≥ 150 and ≥ 182 were accompanied with a significant decrease in hatching rates and the appearance of deformed larvae, respectively. In conclusion, a reliable protocol for gamete collection from live axolotl is established as a laboratory model of in vitro fertilization for urodele amphibians. This protocol may be transferable to endangered urodeles. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Effect of water quality on the feeding ecology of axolotl Ambystoma mexicanum

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    Diego de Jesus Chaparro-Herrera

    2013-10-01

    Full Text Available Ambystoma mexicanum, a highly endangered species, is endemic to lake Xochimilco (Mexico City, Mexico which currently is being negatively affected by the introduction of Oreochromis niloticus (Tilapia and water pollution. During the first weeks of development, when mortality is the highest, Ambystoma mexicanumdepends on a diet of zooplankton. The aim of this study was to check whether contamination levels in lake Xochimilco influence zooplankton consumption by similar size classes of A. mexicanum and Oreochromis niloticus. In this study, we analysed changes in the functional responses and prey preference of A. mexicanum and larval Tilapia in two media, one with filtered lake Xochimilco water and another one with reconstituted water. As prey we used cladocerans (Moina macrocopa, Alona glabra, Macrothrix triserialis and Simocephalus vetulus and ostracods (Heterocypris incongruens. Zooplankton was offered in 5 different densities, 10, 20, 40, 80, 160 ind./mL. Prey consumption by A. mexicanum varied in relation to the species offered and age of the larvae. From the first week to the eighth week prey consumption by A. mexicanum increased by 57%. Our functional response tests showed that regardless of the prey type, prey consumption by A. mexicanum was lower in the contaminated water from lake Xochimilco. Among the zooplankton offered in the contaminated environment predators preferred smaller and slower moving microcrustaceans such as Alona glabra and Heterocypris incongruens. Furthermore, O. niloticus preferred prey such as Moina macrocopa and Macrothrix triserialis in the contaminated medium and was more voracious than the axolotl. Our results indicate that both water quality of the lake and the presence of the more resistant exotic fish adversely impact the survival of this endangered amphibian.

  19. Ex vivo generation of a functional and regenerative wound epithelium from axolotl (Ambystoma mexicanum) skin.

    Science.gov (United States)

    Ferris, Donald R; Satoh, Akira; Mandefro, Berhan; Cummings, Gillian M; Gardiner, David M; Rugg, Elizabeth L

    2010-10-01

    Urodele amphibians (salamanders) are unique among adult vertebrates in their ability to regenerate structurally complete and fully functional limbs. Regeneration is a stepwise process that requires interactions between keratinocytes, nerves and fibroblasts. The formation of a wound epithelium covering the amputation site is an early and necessary event in the process but the molecular mechanisms that underlie the role of the wound epithelium in regeneration remain unclear. We have developed an ex vivo model that recapitulates many features of in vivo wound healing. The model comprises a circular explant of axolotl (Ambystoma mexicanum) limb skin with a central circular, full thickness wound. Re-epithelialization of the wound area is rapid (typically <11 h) and is dependent on metalloproteinase activity. The ex vivo wound epithelium is viable, responds to neuronal signals and is able to participate in ectopic blastema formation and limb regeneration. This ex vivo model provides a reproducible and tractable system in which to study the cellular and molecular events that underlie wound healing and regeneration. © 2010 The Authors. Journal compilation © 2010 Japanese Society of Developmental Biologists.

  20. Patterns of spatial and temporal visceral arch muscle development in the Mexican axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Ericsson, Rolf; Olsson, Lennart

    2004-08-01

    Vertebrate head development is a classical topic that has received renewed attention during the last decade. Most reports use one of a few model organisms (chicken, mouse, zebrafish) and have focused on molecular mechanisms and the role of the neural crest, while cranial muscle development has received less attention. Here we describe cranial muscle differentiation and morphogenesis in the Mexican axolotl, Ambystoma mexicanum. To determine the onset of differentiation we use antibodies against desmin and optical sectioning using confocal laser scanning microscopy on whole-mount immunostained embryos. This technique makes it possible to document the cranial muscle in three dimensions while keeping the specimens intact. Desmin expression starts almost simultaneously in the first, second, and third visceral arch muscles (as in other amphibians studied). Muscle anlagen divide up early into the different elements which constitute the larval cranial musculature. We extend and refine earlier findings, e.g., by documenting a clear division between interhyoideus and interhyoideus posterior. The timing of cranial muscle differentiation differs among vertebrate groups, but seems to be constant within each group. This study provides a morphological foundation for further studies of muscle cell fate and early differentiation. Copyright 2004 Wiley-Liss, Inc.

  1. Induction of Metamorphosis Causes Differences in Sex-Specific Allocation Patterns in Axolotls (Ambystoma mexicanum) that Have Different Growth Histories.

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    Clarkson, Pamela M; Beachy, Christopher K

    2015-12-01

    We tested the hypothesis that salamanders growing at different rates would have allocation patterns that differ among male and female metamorphic and larval salamanders. We raised individual axolotls, Ambystoma mexicanum , on four food regimes: constant high growth (throughout the experiment), constant low growth (restricted throughout the experiment), high growth switched to low growth (ad libitum switched after 140 d to restricted), and low growth switched to high growth (restricted switched after 140 d to ad libitum). Because axolotls are obligate paedomorphs, we exposed half of the salamanders to thyroid hormone to induce metamorphosis. We assayed growth and dissected and weighed gonads and fat bodies. Salamanders that were switched from restricted to ad libitum food regime delayed metamorphosis. In all treatment groups, females had larger gonads than males and males had larger fat bodies than females. The association between storage and reproduction differed between larvae and metamorphs and depended on sex.

  2. Molecular and immunohistochemical analyses of cardiac troponin T during cardiac development in the Mexican axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Zhang, C; Pietras, K M; Sferrazza, G F; Jia, P; Athauda, G; Rueda-de-Leon, E; Rveda-de-Leon, E; Maier, J A; Dube, D K; Lemanski, S L; Lemanski, L F

    2007-01-01

    The Mexican axolotl, Ambystoma mexicanum, is an excellent animal model for studying heart development because it carries a naturally occurring recessive genetic mutation, designated gene c, for cardiac nonfunction. The double recessive mutants (c/c) fail to form organized myofibrils in the cardiac myoblasts resulting in hearts that fail to beat. Tropomyosin expression patterns have been studied in detail and show dramatically decreased expression in the hearts of homozygous mutant embryos. Because of the direct interaction between tropomyosin and troponin T (TnT), and the crucial functions of TnT in the regulation of striated muscle contraction, we have expanded our studies on this animal model to characterize the expression of the TnT gene in cardiac muscle throughout normal axolotl development as well as in mutant axolotls. In addition, we have succeeded in cloning the full-length cardiac troponin T (cTnT) cDNA from axolotl hearts. Confocal microscopy has shown a substantial, but reduced, expression of TnT protein in the mutant hearts when compared to normal during embryonic development. 2006 Wiley-Liss, Inc.

  3. Fine structure of the epidermal Leydig cells in the axolotl Ambystoma mexicanum in relation to their function.

    Science.gov (United States)

    Jarial, M S

    1989-01-01

    The fine structure of the Leydig cells in the epidermis of the strictly aquatic adult axolotl Ambystoma mexicanum resembles that of similar cells in larval salamanders. The major finding of this study is that the mucous secretion of the Leydig cells is released into the intercellular spaces from which it is discharged through pores onto the surface of the epidermis where it forms a mucous layer to protect the skin. Images Figs. 1-2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Figs. 11-13 PMID:2630544

  4. Molecular cloning, sequence analysis and homology modeling of the first caudata amphibian antifreeze-like protein in axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Zhang, Songyan; Gao, Jiuxiang; Lu, Yiling; Cai, Shasha; Qiao, Xue; Wang, Yipeng; Yu, Haining

    2013-08-01

    Antifreeze proteins (AFPs) refer to a class of polypeptides that are produced by certain vertebrates, plants, fungi, and bacteria and which permit their survival in subzero environments. In this study, we report the molecular cloning, sequence analysis and three-dimensional structure of the axolotl antifreeze-like protein (AFLP) by homology modeling of the first caudate amphibian AFLP. We constructed a full-length spleen cDNA library of axolotl (Ambystoma mexicanum). An EST having highest similarity (∼42%) with freeze-responsive liver protein Li16 from Rana sylvatica was identified, and the full-length cDNA was subsequently obtained by RACE-PCR. The axolotl antifreeze-like protein sequence represents an open reading frame for a putative signal peptide and the mature protein composed of 93 amino acids. The calculated molecular mass and the theoretical isoelectric point (pl) of this mature protein were 10128.6 Da and 8.97, respectively. The molecular characterization of this gene and its deduced protein were further performed by detailed bioinformatics analysis. The three-dimensional structure of current AFLP was predicted by homology modeling, and the conserved residues required for functionality were identified. The homology model constructed could be of use for effective drug design. This is the first report of an antifreeze-like protein identified from a caudate amphibian.

  5. Molecular cloning, sequence analysis and phylogeny of first caudata g-type lysozyme in axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Yu, Haining; Gao, Jiuxiang; Lu, Yiling; Guang, Huijuan; Cai, Shasha; Zhang, Songyan; Wang, Yipeng

    2013-11-01

    Lysozymes are key proteins that play important roles in innate immune defense in many animal phyla by breaking down the bacterial cell-walls. In this study, we report the molecular cloning, sequence analysis and phylogeny of the first caudate amphibian g-lysozyme: a full-length spleen cDNA library from axolotl (Ambystoma mexicanum). A goose-type (g-lysozyme) EST was identified and the full-length cDNA was obtained using RACE-PCR. The axolotl g-lysozyme sequence represents an open reading frame for a putative signal peptide and the mature protein composed of 184 amino acids. The calculated molecular mass and the theoretical isoelectric point (pl) of this mature protein are 21523.0 Da and 4.37, respectively. Expression of g-lysozyme mRNA is predominantly found in skin, with lower levels in spleen, liver, muscle, and lung. Phylogenetic analysis revealed that caudate amphibian g-lysozyme had distinct evolution pattern for being juxtaposed with not only anura amphibian, but also with the fish, bird and mammal. Although the first complete cDNA sequence for caudate amphibian g-lysozyme is reported in the present study, clones encoding axolotl's other functional immune molecules in the full-length cDNA library will have to be further sequenced to gain insight into the fundamental aspects of antibacterial mechanisms in caudate.

  6. Leucine-enkephalin-like immunoreactivity is localized in luteinizing hormone-producing cells in the axolotl (Ambystoma mexicanum) pituitary.

    Science.gov (United States)

    Suzuki, Hirohumi; Yamamoto, Toshiharu

    2014-02-01

    In this study, we used immunohistochemical techniques to determine the cell type of leucine-enkephalin (Leu-ENK)-immunoreactive cells in the axolotl (Ambystoma mexicanum) pituitary. Immunoreactive cells were scattered throughout the pars distalis except for the dorso-caudal portion. These cells were immuno-positive for luteinizing hormone (LH), but they were immuno-negative for adrenocorticotrophic, growth, and thyroid-stimulating hormones, as well as prolactin. Immunoelectron microscopy demonstrated that Leu-ENK-like substance and LH co-localized within the same secretory granules. Leu-ENK secreted from gonadotrophs may participate in LH secretion in an autocrine fashion, and/or may participate in the release of sex steroids together with LH. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Detailed tail proteomic analysis of axolotl (Ambystoma mexicanum) using an mRNA-seq reference database.

    Science.gov (United States)

    Demircan, Turan; Keskin, Ilknur; Dumlu, Seda Nilgün; Aytürk, Nilüfer; Avşaroğlu, Mahmut Erhan; Akgün, Emel; Öztürk, Gürkan; Baykal, Ahmet Tarık

    2017-01-01

    Salamander axolotl has been emerging as an important model for stem cell research due to its powerful regenerative capacity. Several advantages, such as the high capability of advanced tissue, organ, and appendages regeneration, promote axolotl as an ideal model system to extend our current understanding on the mechanisms of regeneration. Acknowledging the common molecular pathways between amphibians and mammals, there is a great potential to translate the messages from axolotl research to mammalian studies. However, the utilization of axolotl is hindered due to the lack of reference databases of genomic, transcriptomic, and proteomic data. Here, we introduce the proteome analysis of the axolotl tail section searched against an mRNA-seq database. We translated axolotl mRNA sequences to protein sequences and annotated these to process the LC-MS/MS data and identified 1001 nonredundant proteins. Functional classification of identified proteins was performed by gene ontology searches. The presence of some of the identified proteins was validated by in situ antibody labeling. Furthermore, we have analyzed the proteome expressional changes postamputation at three time points to evaluate the underlying mechanisms of the regeneration process. Taken together, this work expands the proteomics data of axolotl to contribute to its establishment as a fully utilized model. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Low submetamorphic doses of dexamethasone and thyroxine induce complete metamorphosis in the axolotl (Ambystoma mexicanum) when injected together.

    Science.gov (United States)

    Kühn, Eduard R; De Groef, Bert; Grommen, Sylvia V H; Van der Geyten, Serge; Darras, Veerle M

    2004-06-01

    Entanglement of functions between the adrenal (or interrenal) and thyroid axis has been well described for all vertebrates and can be tracked down up to the level of gene expression. Both thyroid hormones and corticosteroids may induce morphological changes leading to metamorphosis climax in the neotenic Mexican axolotl (Ambystoma mexicanum). In a first series of experiments, metamorphosis was induced with an injection of 25 microg T(4) on three alternate days as judged by a decrease in body weight and tail height together with complete gill resorption. This injection also resulted in elevated plasma concentrations of T(3) and corticosterone. Previous results have indicated that the same dose of dexamethasone (DEX) is ineffective in this regard (Gen. Comp. Endocrinol. 127 (2002) 157). In a second series of experiments low doses of T(4) (0.5 microg) or DEX (5 microg) were ineffective to induce morphological changes. However, when these submetamorphic doses were injected together, morphological changes were observed within one week leading to complete metamorphosis. It is concluded that thyroid hormones combined with corticosteroids are essential for metamorphosis in the axolotl and that only high doses of either thyroid hormone or corticosteroid can induce morphological changes when injected separately.

  9. Effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the Mexican axolotl (Ambystoma

    Directory of Open Access Journals (Sweden)

    Samuels Amy K

    2008-02-01

    Full Text Available Abstract Background Thyroid hormones (TH induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T4. We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum using 5 and 50 nM T4, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28, and used microarray analysis to quantify mRNA abundances. Results Individuals reared in the higher T4 concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by Day 28. In contrast, initiation of metamorphosis was delayed in the lower T4 concentration and none of the individuals completed metamorphosis by Day 28. We identified 402 genes that were statistically differentially expressed by ≥ two-fold between T4 treatments at one or more non-Day 0 sampling times. To complement this analysis, we used linear and quadratic regression to identify 542 and 709 genes that were differentially expressed by ≥ two-fold in the 5 and 50 nM T4 treatments, respectively. Conclusion We found that T4 concentration affected the timing of gene expression and the shape of temporal gene expression profiles. However, essentially all of the identified genes were similarly affected by 5 and 50 nM T4. We discuss genes and biological processes that appear to be common to salamander and anuran metamorphosis, and also highlight clear transcriptional differences. Our results show that gene expression in axolotls is diverse and precise, and that axolotls provide new insights about amphibian metamorphosis.

  10. Effect of thyroid hormone concentration on the transcriptional response underlying induced metamorphosis in the Mexican axolotl (Ambystoma).

    Science.gov (United States)

    Page, Robert B; Voss, Stephen R; Samuels, Amy K; Smith, Jeramiah J; Putta, Srikrishna; Beachy, Christopher K

    2008-02-11

    Thyroid hormones (TH) induce gene expression programs that orchestrate amphibian metamorphosis. In contrast to anurans, many salamanders do not undergo metamorphosis in nature. However, they can be induced to undergo metamorphosis via exposure to thyroxine (T4). We induced metamorphosis in juvenile Mexican axolotls (Ambystoma mexicanum) using 5 and 50 nM T4, collected epidermal tissue from the head at four time points (Days 0, 2, 12, 28), and used microarray analysis to quantify mRNA abundances. Individuals reared in the higher T4 concentration initiated morphological and transcriptional changes earlier and completed metamorphosis by Day 28. In contrast, initiation of metamorphosis was delayed in the lower T4 concentration and none of the individuals completed metamorphosis by Day 28. We identified 402 genes that were statistically differentially expressed by > or = two-fold between T4 treatments at one or more non-Day 0 sampling times. To complement this analysis, we used linear and quadratic regression to identify 542 and 709 genes that were differentially expressed by > or = two-fold in the 5 and 50 nM T4 treatments, respectively. We found that T4 concentration affected the timing of gene expression and the shape of temporal gene expression profiles. However, essentially all of the identified genes were similarly affected by 5 and 50 nM T4. We discuss genes and biological processes that appear to be common to salamander and anuran metamorphosis, and also highlight clear transcriptional differences. Our results show that gene expression in axolotls is diverse and precise, and that axolotls provide new insights about amphibian metamorphosis.

  11. Role of cranial neural crest cells in visceral arch muscle positioning and morphogenesis in the Mexican axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Ericsson, Rolf; Cerny, Robert; Falck, Pierre; Olsson, Lennart

    2004-10-01

    The role of cranial neural crest cells in the formation of visceral arch musculature was investigated in the Mexican axolotl, Ambystoma mexicanum. DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine, perchlorate) labeling and green fluorescent protein (GFP) mRNA injections combined with unilateral transplantations of neural folds showed that neural crest cells contribute to the connective tissues but not the myofibers of developing visceral arch muscles in the mandibular, hyoid, and branchial arches. Extirpations of individual cranial neural crest streams demonstrated that neural crest cells are necessary for correct morphogenesis of visceral arch muscles. These do, however, initially develop in their proper positions also in the absence of cranial neural crest. Visceral arch muscles forming in the absence of neural crest cells start to differentiate at their origins but fail to extend toward their insertions and may have a frayed appearance. Our data indicate that visceral arch muscle positioning is controlled by factors that do not have a neural crest origin. We suggest that the cranial neural crest-derived connective tissues provide directional guidance important for the proper extension of the cranial muscles and the subsequent attachment to the insertion on the correct cartilage. In a comparative context, our data from the Mexican axolotl support the view that the cranial neural crest plays a fundamental role in the development of not only the skeleton of the vertebrate head but also in the morphogenesis of the cranial muscles and that this might be a primitive feature of cranial development in vertebrates. 2004 Wiley-Liss, Inc.

  12. Identification of Mutant Genes and Introgressed Tiger Salamander DNA in the Laboratory Axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Woodcock, M Ryan; Vaughn-Wolfe, Jennifer; Elias, Alexandra; Kump, D Kevin; Kendall, Katharina Denise; Timoshevskaya, Nataliya; Timoshevskiy, Vladimir; Perry, Dustin W; Smith, Jeramiah J; Spiewak, Jessica E; Parichy, David M; Voss, S Randal

    2017-01-31

    The molecular genetic toolkit of the Mexican axolotl, a classic model organism, has matured to the point where it is now possible to identify genes for mutant phenotypes. We used a positional cloning-candidate gene approach to identify molecular bases for two historic axolotl pigment phenotypes: white and albino. White (d/d) mutants have defects in pigment cell morphogenesis and differentiation, whereas albino (a/a) mutants lack melanin. We identified in white mutants a transcriptional defect in endothelin 3 (edn3), encoding a peptide factor that promotes pigment cell migration and differentiation in other vertebrates. Transgenic restoration of Edn3 expression rescued the homozygous white mutant phenotype. We mapped the albino locus to tyrosinase (tyr) and identified polymorphisms shared between the albino allele (tyr a ) and tyr alleles in a Minnesota population of tiger salamanders from which the albino trait was introgressed. tyr a has a 142 bp deletion and similar engineered alleles recapitulated the albino phenotype. Finally, we show that historical introgression of tyr a significantly altered genomic composition of the laboratory axolotl, yielding a distinct, hybrid strain of ambystomatid salamander. Our results demonstrate the feasibility of identifying genes for traits in the laboratory Mexican axolotl.

  13. Identification of Differentially Expressed Thyroid Hormone Responsive Genes from the Brain of the Mexican Axolotl (Ambystoma mexicanum) ✧

    Science.gov (United States)

    Huggins, P; Johnson, CK; Schoergendorfer, A; Putta, S; Bathke, AC; Stromberg, AJ; Voss, SR

    2011-01-01

    The Mexican axolotl (Ambystoma mexicanum) presents an excellent model to investigate mechanisms of brain development that are conserved among vertebrates. In particular, metamorphic changes of the brain can be induced in free-living aquatic juveniles and adults by simply adding thyroid hormone (T4) to rearing water. Whole brains were sampled from juvenile A. mexicanum that were exposed to 0, 8, and 18 days of 50 nM T4, and these were used to isolate RNA and make normalized cDNA libraries for 454 DNA sequencing. A total of 1,875,732 high quality cDNA reads were assembled with existing ESTs to obtain 5,884 new contigs for human RefSeq protein models, and to develop a custom Affymetrix gene expression array (Amby_002) with approximately 20,000 probe sets. The Amby_002 array was used to identify 303 transcripts that differed statistically (p 1.5) as a function of days of T4 treatment. Further statistical analyses showed that Amby_002 performed concordantly in comparison to an existing, small format expression array. This study introduces a new A. mexicanum microarray resource for the community and the first lists of T4-responsive genes from the brain of a salamander amphibian. PMID:21457787

  14. Identification of differentially expressed thyroid hormone responsive genes from the brain of the Mexican Axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Huggins, P; Johnson, C K; Schoergendorfer, A; Putta, S; Bathke, A C; Stromberg, A J; Voss, S R

    2012-01-01

    The Mexican axolotl (Ambystoma mexicanum) presents an excellent model to investigate mechanisms of brain development that are conserved among vertebrates. In particular, metamorphic changes of the brain can be induced in free-living aquatic juveniles and adults by simply adding thyroid hormone (T4) to rearing water. Whole brains were sampled from juvenile A. mexicanum that were exposed to 0, 8, and 18 days of 50 nM T4, and these were used to isolate RNA and make normalized cDNA libraries for 454 DNA sequencing. A total of 1,875,732 high quality cDNA reads were assembled with existing ESTs to obtain 5884 new contigs for human RefSeq protein models, and to develop a custom Affymetrix gene expression array (Amby_002) with approximately 20,000 probe sets. The Amby_002 array was used to identify 303 transcripts that differed statistically (p1.5) as a function of days of T4 treatment. Further statistical analyses showed that Amby_002 performed concordantly in comparison to an existing, small format expression array. This study introduces a new A. mexicanum microarray resource for the community and the first lists of T4-responsive genes from the brain of a salamander amphibian. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Muscular derivatives of the cranialmost somites revealed by long-term fate mapping in the Mexican axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Piekarski, Nadine; Olsson, Lennart

    2007-01-01

    The fate of single somites has not been analyzed from a comparative perspective with modern cell-marking methods. Most of what we know is based on work using quail-chick chimeras. Consequently, to what degree cell fate has been conserved despite the anatomical differences among vertebrates is unknown. We have analyzed the cell fate of the cranialmost somites, with the focus on somite two, in the Mexican axolotl (Ambystoma mexicanum). Somite cells were marked by injection of dextran-fluorescein and detected using immunofluorescence after 2 months of development in paraffin sections. Our data confirm and extend earlier studies based on classical histology in salamanders. We show that somite two contributes to different muscles, skeletal elements, and connective tissues of the head and cranial trunk region. Cells from somites two and three migrate latero-ventrally and contribute to the hypobranchial muscles mm. geniohyoideus and rectus cervicis. We provide evidence that the specific formation of the hypobranchial musculature from ventral processes of the somites might be variable in different classes of vertebrates. We further demonstrate that mm. cucullaris and dilatator laryngis, which were earlier thought to have a branchial origin, arise from somitic material in a manner very similar to the findings in quail-chick chimeras. Our findings indicate that the pattern of somitic derivatives is highly conserved within tetrapods.

  16. Glucose transporter distribution in the vessels of the central nervous system of the axolotl Ambystoma mexicanum (Urodela: Ambystomatidae).

    Science.gov (United States)

    Lazzari, Maurizio; Bettini, Simone; Ciani, Franco; Franceschini, Valeria

    2008-10-01

    The GLUT-1 isoform of the glucose transporter is commonly considered a reliable molecular marker of blood-brain barrier endothelia in the neural vasculature organized in a three-dimensional network of single vessels. The central nervous system of the axolotl Ambystoma mexicanum is characterized by a vascular architecture that contains both single and paired vessels. The presence and distribution of the GLUT-1 transporter are studied in this urodele using both immunoperoxidase histochemistry and immunogold technique. Light microscopy reveals immunopositivity in both parenchymal and meningeal vessels. The transverse-sectioned pairs of vessels do not show the same size. Furthermore, in the same pair, the two elements often differ in diameter. The main regions of the central nervous system show a different percentage of the paired structures. Only immunogold cytochemistry reveals different staining intensity in the two adjoined elements of a vascular pair. Colloidal gold particles show an asymmetric distribution in the endothelia of both single and paired vessels. These particles are more numerous on the abluminal surface than on the luminal one. The particle density is calculated in both vascular types. The different values could indicate functional differences between single and paired vessels and between the two adjoined elements of a pair, regarding glucose transport.

  17. Crystal structure of axolotl (Ambystoma mexicanum) liver bile acid-binding protein bound to cholic and oleic acid.

    Science.gov (United States)

    Capaldi, Stefano; Guariento, Mara; Perduca, Massimiliano; Di Pietro, Santiago M; Santomé, José A; Monaco, Hugo L

    2006-07-01

    The family of the liver bile acid-binding proteins (L-BABPs), formerly called liver basic fatty acid-binding proteins (Lb-FABPs) shares fold and sequence similarity with the paralogous liver fatty acid-binding proteins (L-FABPs) but has a different stoichiometry and specificity of ligand binding. This article describes the first X-ray structure of a member of the L-BABP family, axolotl (Ambystoma mexicanum) L-BABP, bound to two different ligands: cholic and oleic acid. The protein binds one molecule of oleic acid in a position that is significantly different from that of either of the two molecules that bind to rat liver FABP. The stoichiometry of binding of cholate is of two ligands per protein molecule, as observed in chicken L-BABP. The cholate molecule that binds buried most deeply into the internal cavity overlaps well with the analogous bound to chicken L-BABP, whereas the second molecule, which interacts with the first only through hydrophobic contacts, is more external and exposed to the solvent. (c) 2006 Wiley-Liss, Inc.

  18. Regulation of Regenerative Responses by Factors in the Extracellular Matrix during Axolotl (Ambystoma mexicanum) Limb Regeneration

    OpenAIRE

    Phan, Anne Quy

    2014-01-01

    Salamanders are unique among adult vertebrates in their ability to regenerate complex body structures after traumatic injury. Axolotl limb regeneration is a stepwise sequence of three requisite processes: (1) scarless wound healing to generate a regenerative wound epithelium, (2) blastema formation by migration, proliferation and dedifferentiation to create a mass of multipotent regeneration-competent progenitor cells, and (3) induction of pattern formation by interaction of cells with opposi...

  19. Dual embryonic origin and patterning of the pharyngeal skeleton in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Sefton, Elizabeth M; Piekarski, Nadine; Hanken, James

    2015-01-01

    The impressive morphological diversification of vertebrates was achieved in part by innovation and modification of the pharyngeal skeleton. Extensive fate mapping in amniote models has revealed a primarily cranial neural crest derivation of the pharyngeal skeleton. Although comparable fate maps of amphibians produced over several decades have failed to document a neural crest derivation of ventromedial elements in these vertebrates, a recent report provides evidence of a mesodermal origin of one of these elements, basibranchial 2, in the axolotl. We used a transgenic labeling protocol and grafts of labeled cells between GFP+ and white embryos to derive a fate map that describes contributions of both cranial neural crest and mesoderm to the axolotl pharyngeal skeleton, and we conducted additional experiments that probe the mechanisms that underlie mesodermal patterning. Our fate map confirms a dual embryonic origin of the pharyngeal skeleton in urodeles, including derivation of basibranchial 2 from mesoderm closely associated with the second heart field. Additionally, heterotopic transplantation experiments reveal lineage restriction of mesodermal cells that contribute to pharyngeal cartilage. The mesoderm-derived component of the pharyngeal skeleton appears to be particularly sensitive to retinoic acid (RA): administration of exogenous RA leads to loss of the second basibranchial, but not the first. Neural crest was undoubtedly critical in the evolution of the vertebrate pharyngeal skeleton, but mesoderm may have played a central role in forming ventromedial elements, in particular. When and how many times during vertebrate phylogeny a mesodermal contribution to the pharyngeal skeleton evolved remain to be resolved. © 2015 Wiley Periodicals, Inc.

  20. Severe necrotizing myocarditis caused by serratia marcescens infection in an axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Del-Pozo, J; Girling, S; Pizzi, R; Mancinelli, E; Else, R W

    2011-05-01

    This report provides the first account of the pathological changes associated with infection by Serratia marcescens in an adult male axolotl. The infection resulted in septicaemia with severe multifocal necrotizing myocarditis. The latter lesion evolved to cardiac rupture, haemopericardium and death resulting from cardiac tamponade. This animal was exposed to higher than usual temperatures (24-25 °C) 2 weeks before the onset of disease and this may have resulted in immunocompromise and opportunistic bacterial infection. S. marcescens was isolated from the coelomic and pericardial cavity. Both isolates were identical and were resistant to β-lactam antibiotics, but not to aminoglycosides or fluoroquinolones. The production of red prodigiosin pigment by the bacterium suggested an environmental origin. Overall, the clinical and histopathological presentation suggests that S. marcescens should be included in the list of aetiological agents of the 'red-leg'/bacterial dermatosepticaemia syndrome of amphibians. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Comparative pelvic development of the axolotl (Ambystoma mexicanum) and the Australian lungfish (Neoceratodus forsteri): conservation and innovation across the fish-tetrapod transition.

    Science.gov (United States)

    Boisvert, Catherine Anne; Joss, Jean Mp; Ahlberg, Per E

    2013-01-23

    The fish-tetrapod transition was one of the major events in vertebrate evolution and was enabled by many morphological changes. Although the transformation of paired fish fins into tetrapod limbs has been a major topic of study in recent years, both from paleontological and comparative developmental perspectives, the interest has focused almost exclusively on the distal part of the appendage and in particular the origin of digits. Relatively little attention has been paid to the transformation of the pelvic girdle from a small unipartite structure to a large tripartite weight-bearing structure, allowing tetrapods to rely mostly on their hindlimbs for locomotion. In order to understand how the ischium and the ilium evolved and how the acetabulum was reoriented during this transition, growth series of the Australian lungfish Neoceratodus forsteri and the Mexican axolotl Ambystoma mexicanum were cleared and stained for cartilage and bone and immunostained for skeletal muscles. In order to understand the myological developmental data, hypotheses about the homologies of pelvic muscles in adults of Latimeria, Neoceratodus and Necturus were formulated based on descriptions from the literature of the coelacanth (Latimeria), the Australian Lungfish (Neoceratodus) and a salamander (Necturus). In the axolotl and the lungfish, the chondrification of the pelvic girdle starts at the acetabula and progresses anteriorly in the lungfish and anteriorly and posteriorly in the salamander. The ilium develops by extending dorsally to meet and connect to the sacral rib in the axolotl. Homologous muscles develop in the same order with the hypaxial musculature developing first, followed by the deep, then the superficial pelvic musculature. Development of the pelvic endoskeleton and musculature is very similar in Neoceratodus and Ambystoma. If the acetabulum is seen as being a fixed landmark, the evolution of the ischium only required pubic pre-chondrogenic cells to migrate posteriorly. It

  2. Axolotl hemoglobin: cDNA-derived amino acid sequences of two alpha globins and a beta globin from an adult Ambystoma mexicanum.

    Science.gov (United States)

    Shishikura, Fumio; Takeuchi, Hiro-aki; Nagai, Takatoshi

    2005-11-01

    Erythrocytes of the adult axolotl, Ambystoma mexicanum, have multiple hemoglobins. We separated and purified two kinds of hemoglobin, termed major hemoglobin (Hb M) and minor hemoglobin (Hb m), from a five-year-old male by hydrophobic interaction column chromatography on Alkyl Superose. The hemoglobins have two distinct alpha type globin polypeptides (alphaM and alpham) and a common beta globin polypeptide, all of which were purified in FPLC on a reversed-phase column after S-pyridylethylation. The complete amino acid sequences of the three globin chains were determined separately using nucleotide sequencing with the assistance of protein sequencing. The mature globin molecules were composed of 141 amino acid residues for alphaM globin, 143 for alpham globin and 146 for beta globin. Comparing primary structures of the five kinds of axolotl globins, including two previously established alpha type globins from the same species, with other known globins of amphibians and representatives of other vertebrates, we constructed phylogenetic trees for amphibian hemoglobins and tetrapod hemoglobins. The molecular trees indicated that alphaM, alpham, beta and the previously known alpha major globin were adult types of globins and the other known alpha globin was a larval type. The existence of two to four more globins in the axolotl erythrocyte is predicted.

  3. Neurotrophic regulation of epidermal dedifferentiation during wound healing and limb regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, A; Graham, G M C; Bryant, S V; Gardiner, D M

    2008-07-15

    Adult urodeles (salamanders) are unique in their ability to regenerate complex organs perfectly. The recently developed Accessory Limb Model (ALM) in the axolotl provides an opportunity to identify and characterize the essential signaling events that control the early steps in limb regeneration. The ALM demonstrates that limb regeneration progresses in a stepwise fashion that is dependent on signals from the wound epidermis, nerves and dermal fibroblasts from opposite sides of the limb. When all the signals are present, a limb is formed de novo. The ALM thus provides an opportunity to identify and characterize the signaling pathways that control blastema morphogenesis and limb regeneration. In the present study, we have utilized the ALM to identity the buttonhead-like zinc-finger transcription factor, Sp9, as being involved in the formation of the regeneration epithelium. Sp9 expression is induced in basal keratinocytes of the apical blastema epithelium in a pattern that is comparable to its expression in developing limb buds, and it thus is an important marker for dedifferentiation of the epidermis. Induction of Sp9 expression is nerve-dependent, and we have identified KGF as an endogenous nerve factor that induces expression of Sp9 in the regeneration epithelium.

  4. Neurotrophic regulation of fibroblast dedifferentiation during limb skeletal regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, Akira; Cummings, Gillian M C; Bryant, Susan V; Gardiner, David M

    2010-01-15

    The ability of animals to repair tissue damage is widespread and impressive. Among tissues, the repair and remodeling of bone occurs during growth and in response to injury; however, loss of bone above a threshold amount is not regenerated, resulting in a "critical-size defect" (CSD). The development of therapies to replace or regenerate a CSD is a major focus of research in regenerative medicine and tissue engineering. Adult urodeles (salamanders) are unique in their ability to regenerate complex tissues perfectly, yet like mammals do not regenerate a CSD. We report on an experimental model for the regeneration of a CSD in the axolotl (the Excisional Regeneration Model) that allows for the identification of signals to induce fibroblast dedifferentiation and skeletal regeneration. This regenerative response is mediated in part by BMP signaling, as is the case in mammals; however, a complete regenerative response requires the induction of a population of undifferentiated, regeneration-competent cells. These cells can be induced by signaling from limb amputation to generate blastema cells that can be grafted to the wound, as well as by signaling from a nerve and a wound epithelium to induce blastema cells from fibroblasts within the wound environment. Copyright 2009 Elsevier Inc. All rights reserved.

  5. Dual embryonic origin of the hyobranchial apparatus in the Mexican axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Davidian, Asya; Malashichev, Yegor

    2013-01-01

    Traditionally, the cartilaginous viscerocranium of vertebrates is considered as neural crest (NC)-derived. Morphological work carried out on amphibian embryos in the first half of the XX century suggested potentially mesodermal origin for some hyobranchial elements. Since then, the embryonic sources of the hyobranchial apparatus in amphibians has not been investigated due to lack of an appropriate long-term labelling system. We performed homotopic transplantations of neural folds along with the majority of cells of the presumptive NC, and/or fragments of the head lateral plate mesoderm (LPM) from transgenic GFP+ into white embryos. In these experiments, the NC-derived GFP+ cells contributed to all hyobranchial elements, except for basibranchial 2, whereas the grafting of GFP+ head mesoderm led to a reverse labelling result. The grafting of only the most ventral part of the head LPM resulted in marking of the basibranchial 2 and the heart myocardium, implying their origin from a common mesodermal region. This is the first evidence of contribution of LPM of the head to cranial elements in any vertebrate. If compared to fish, birds, and mammals, in which all branchial skeletal elements are NC-derived, the axolotl (probably this is true for all amphibians) demonstrates an evolutionary deviation, in which the head LPM replaces NC cells in a hyobranchial element. This implies that cells of different embryonic origin may have the same developmental program, leading to the formation of identical (homologous) elements of the skeleton.

  6. Functional and structural regeneration in the axolotl heart (Ambystoma mexicanum) after partial ventricular amputation.

    Science.gov (United States)

    Cano-Martínez, Agustina; Vargas-González, Alvaro; Guarner-Lans, Verónica; Prado-Zayago, Esteban; León-Oleda, Martha; Nieto-Lima, Betzabé

    2010-01-01

    "In the present study we evaluated the effect of partial ventricular amputation (PVA) in the heart of the adult urodele amphibian (Ambystoma mexicanum) in vivo on spontaneous heart contractile activity recorded in vitro in association to the structural recovery at one, five, 30 and 90 days after injury. One day after PVA, ventricular-tension (VT) (16 ± 3%), atrium-tension (AT) (46 ± 4%) and heart rate (HR) (58+10%) resulted lower in comparison to control hearts. On days five, 30 and 90 after damage, values achieved a 61 ± 5, 93 ± 3, and 98 ± 5% (VT), 60 ± 4, 96 ± 3 and 99 ± 5% (AT) and 74 ± 5, 84 ± 10 and 95 ± 10% (HR) of the control values, respectively. Associated to contractile activity recovery we corroborated a gradual tissue restoration by cardiomyocyte proliferation. Our results represent the first quantitative evidence about the recovery of heart of A. mexicanum restores its functional capacity concomitantly to the structural recovery of the myocardium by proliferation of cardiomyocytes after PVA. These properties make the heart of A. mexicanum a potential model to study the mechanisms underlying heart regeneration in adult vertebrates in vivo.

  7. Characterization of glycosaminoglycans during tooth development and mineralization in the axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Wistuba, J; Völker, W; Ehmcke, J; Clemen, G

    2003-10-01

    Glycosaminoglycans (GAGs) involved in the formation of the teeth of Ambystoma mexicanum were located and characterized with the cuprolinic blue (CB) staining method and transmission electron microscopy (TEM). Glycosaminoglycan-cuprolinic blue precipitates (GAGCB) were found in different compartments of the mineralizing tissue. Various populations of elongated GAGCB could be discriminated both according to their size and their preferential distribution in the extracellular matrix (ECM). GAGCB populations that differ in their composition could be attributed not only to the compartments of the ECM but also to different zones and to different tooth types (early-larval and transformed). Larger precipitates were only observed within the dentine matrix of the shaft of the early-larval tooth. The composition of the populations differed significantly between the regions of the transformed tooth: pedicel, shaft and dividing zone. In later stages of tooth formation, small-sized GAGCBs were seen as intracellular deposits in the ameloblasts. It is concluded that the composition of GAGCB populations seems to play a role in the mineralization processes during tooth development in A. mexicanum and influence qualitative characteristics of the mineral in different tooth types and zones, and it is suggested that GAGs might be resorbed by the enamel epithelium during the late phase of enamel formation.

  8. Corticotropin-releasing hormone-mediated metamorphosis in the neotenic axolotl Ambystoma mexicanum: synergistic involvement of thyroxine and corticoids on brain type II deiodinase.

    Science.gov (United States)

    Kühn, Eduard R; De Groef, Bert; Van der Geyten, Serge; Darras, Veerle M

    2005-08-01

    In the present study, morphological changes leading to complete metamorphosis have been induced in the neotenic axolotl Ambystoma mexicanum using a submetamorphic dose of T(4) together with an injection of corticotropin-releasing hormone (CRH). An injection of CRH alone is ineffective in this regard presumably due to a lack of thyrotropic stimulation. Using this low hormone profile for induction of metamorphosis, the deiodinating enzymes D2 and D3 known to be present in amphibians were measured in liver and brain 24h following an intraperitoneal injection. An injection of T(4) alone did not influence liver nor brain D2 and D3, but dexamethasone (DEX) or CRH alone or in combination with T(4) decreased liver D2 and D3. Brain D2 activity was slightly increased with a higher dose of DEX, though CRH did not have this effect. A profound synergistic effect occurred when T(4) and DEX or CRH were injected together, in the dose range leading to metamorphosis, increasing brain D2 activity more than fivefold. This synergistic effect was not found in the liver. It is concluded that brain T(3) availability may play an important role for the onset of metamorphosis in the neotenic axolotl.

  9. Terminal-Nerve-Derived Neuropeptide Y Modulates Physiological Responses in the Olfactory Epithelium of Hungry Axolotls (Ambystoma mexicanum)

    OpenAIRE

    Mousley, Angela; Polese, Gianluca; Marks, Nikki J.; Eisthen, Heather L.

    2006-01-01

    The vertebrate brain actively regulates incoming sensory information, effectively filtering input and focusing attention toward environmental stimuli that are most relevant to the animal's behavioral context or physiological state. Such centrifugal modulation has been shown to play an important role in processing in the retina and cochlea, but has received relatively little attention in olfaction. The terminal nerve, a cranial nerve that extends underneath the lamina propria surrounding the o...

  10. Ontogeny of the VIP system in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum: successive appearance of co-existing PACAP and NOS.

    Science.gov (United States)

    Badawy, Gamal; Reinecke, Manfred

    2003-03-01

    Evidence for the presence and potential co-existence of vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP) and nitric oxide synthase (NOS) in gastro-intestinal endocrine cells and/or nerve fibers is conflicting and very few results exist on development. This immunofluorescence study aims to clarify the appearance and localization of VIP, PACAP and NOS in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum, during ontogeny. VIP-immunoreactivity appeared in nerve fibers as early as on day 3 after hatching likely indicating a particular role, such as a trophic action, of VIP in very early development. PACAP-immunoreactivity was observed 3 days later within the VIP-immunoreactive (-IR) fibers. From this time on, VIP- and PACAP-immunoreactivity exhibited complete co-existence. VIP/PACAP-IR fibers were found throughout the gastro-intestinal tract. They were most prominent in the myenteric plexus and the muscle layers and less frequent in the submucosa. NOS-immunoreactivity appeared as late as at the 1st (64 days) juvenile stage in a subpopulation of the VIP/PACAP-IR fibers that contacted submucosal arteries. We found only very few VIP/PACAP-IR perikarya, indicating that part of the VIP/PACAP-IR fibers is of extrinsic origin. On day 12 and in the 1st and 2nd (104 days) juvenile stage, infrequent PACAP-IR entero-endocrine cells were noted, while neither VIP- nor NOS-immunoreactivity occurred in endocrine cells at any stage of development. The complete coexistence of neuronal PACAP- and VIP-immunoreactivities and their very early appearance in ontogeny may suggest important and coordinated roles of both peptides in the control of Axolotl gastro-intestinal activity, while the VIP/ PACAP/NOS-IR fibers may be involved in the regulation of submucosal blood flow.

  11. [Specific growth rate and the rate of energy metabolism in the ontogenesis of axolotl, Ambystoma mexicanum (Amphibia: Ambystomatidae)].

    Science.gov (United States)

    Vladimirova, I G; Kleĭmenov, S Iu; Alekseeva, T A; Radzinskaia, L I

    2003-01-01

    Concordant changes in the rate of energy metabolism and specific growth rate of axolotls have been revealed. Several periods of ontogeny are distinguished, which differ in the ratio of energy metabolism to body weight and, therefore, are described by different allometric equations. It is suggested that the specific growth rate of an animal determines the type of dependence of energy metabolism on body weight.

  12. Analysis of the expression and function of Wnt-5a and Wnt-5b in developing and regenerating axolotl (Ambystoma mexicanum) limbs.

    Science.gov (United States)

    Ghosh, Sukla; Roy, Stéphane; Séguin, Carl; Bryant, Susan V; Gardiner, David M

    2008-05-01

    Urodele amphibians are unique adult vertebrates because they are able to regenerate body parts after amputation. Studies of urodele limb regeneration, the key model system for vertebrate regeneration, have led to an understanding of the origin of blastema cells and the importance of positional interactions between blastema cells in the control of growth and pattern formation. Progress is now being made in the identification of the signaling pathways that regulate dedifferentiation, blastema morphogenesis, growth and pattern formation. Members of the Wnt family of secreted proteins are expressed in developing and regenerating limbs, and have the potential to control growth, pattern formation and differentiation. We have studied the expression of two non-canonical Wnt genes, Wnt-5a and Wnt-5b. We report that they are expressed in equivalent patterns during limb development and limb regeneration in the axolotl (Ambystoma mexicanum), and during limb development in other tetrapods, implying conservation of function. Our analysis of the effects of ectopic Wnt-5a expression is consistent with the hypothesis that canonical Wnt signaling functions during the early stages of regeneration to control the dedifferentiation of stump cells giving rise to the regeneration-competent cells of the blastema.

  13. Using Ambystoma mexicanum (Mexican axolotl) embryos, chemical genetics, and microarray analysis to identify signaling pathways associated with tissue regeneration.

    Science.gov (United States)

    Ponomareva, Larissa V; Athippozhy, Antony; Thorson, Jon S; Voss, S Randal

    2015-12-01

    Amphibian vertebrates are important models in regenerative biology because they present exceptional regenerative capabilities throughout life. However, it takes considerable effort to rear amphibians to juvenile and adult stages for regeneration studies, and the relatively large sizes that frogs and salamanders achieve during development make them difficult to use in chemical screens. Here, we introduce a new tail regeneration model using late stage Mexican axolotl embryos. We show that axolotl embryos completely regenerate amputated tails in 7days before they exhaust their yolk supply and begin to feed. Further, we show that axolotl embryos can be efficiently reared in microtiter plates to achieve moderate throughput screening of soluble chemicals to investigate toxicity and identify molecules that alter regenerative outcome. As proof of principle, we identified integration 1 / wingless (Wnt), transforming growth factor beta (Tgf-β), and fibroblast growth factor (Fgf) pathway antagonists that completely block tail regeneration and additional chemicals that significantly affected tail outgrowth. Furthermore, we used microarray analysis to show that inhibition of Wnt signaling broadly affects transcription of genes associated with Wnt, Fgf, Tgf-β, epidermal growth factor (Egf), Notch, nerve growth factor (Ngf), homeotic gene (Hox), rat sarcoma/mitogen-activated protein kinase (Ras/Mapk), myelocytomatosis viral oncogene (Myc), tumor protein 53 (p53), and retinoic acid (RA) pathways. Punctuated changes in the expression of genes known to regulate vertebrate development were observed; this suggests the tail regeneration transcriptional program is hierarchically structured and temporally ordered. Our study establishes the axolotl as a chemical screening model to investigate signaling pathways associated with tissue regeneration. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Absence of mutation at the 5'-upstream promoter region of the TPM4 gene from cardiac mutant axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Denz, Christopher R; Zhang, Chi; Jia, Pingping; Du, Jianfeng; Huang, Xupei; Dube, Syamalima; Thomas, Anish; Poiesz, Bernard J; Dube, Dipak K

    2011-09-01

    Tropomyosins are a family of actin-binding proteins that show cell-specific diversity by a combination of multiple genes and alternative RNA splicing. Of the 4 different tropomyosin genes, TPM4 plays a pivotal role in myofibrillogenesis as well as cardiac contractility in amphibians. In this study, we amplified and sequenced the upstream regulatory region of the TPM4 gene from both normal and mutant axolotl hearts. To identify the cis-elements that are essential for the expression of the TPM4, we created various deletion mutants of the TPM4 promoter DNA, inserted the deleted segments into PGL3 vector, and performed promoter-reporter assay using luciferase as the reporter gene. Comparison of sequences of the promoter region of the TPM4 gene from normal and mutant axolotl revealed no mutations in the promoter sequence of the mutant TPM4 gene. CArG box elements that are generally involved in controlling the expression of several other muscle-specific gene promoters were not found in the upstream regulatory region of the TPM4 gene. In deletion experiments, loss of activity of the reporter gene was noted upon deletion which was then restored upon further deletion suggesting the presence of both positive and negative cis-elements in the upstream regulatory region of the TPM4 gene. We believe that this is the first axolotl promoter that has ever been cloned and studied with clear evidence that it functions in mammalian cell lines. Although striated muscle-specific cis-acting elements are absent from the promoter region of TPM4 gene, our results suggest the presence of positive and negative cis-elements in the promoter region, which in conjunction with positive and negative trans-elements may be involved in regulating the expression of TPM4 gene in a tissue-specific manner.

  15. Positional information in axolotl and mouse limb extracellular matrix is mediated via heparan sulfate and fibroblast growth factor during limb regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Phan, Anne Q; Lee, Jangwoo; Oei, Michelle; Flath, Craig; Hwe, Caitlyn; Mariano, Rachele; Vu, Tiffany; Shu, Cynthia; Dinh, Andrew; Simkin, Jennifer; Muneoka, Ken; Bryant, Susan V; Gardiner, David M

    2015-08-01

    Urodele amphibians are unique among adult vertebrates in their ability to regenerate complex body structures after traumatic injury. In salamander regeneration, the cells maintain a memory of their original position and use this positional information to recreate the missing pattern. We used an in vivo gain-of-function assay to determine whether components of the extracellular matrix (ECM) have positional information required to induce formation of new limb pattern during regeneration. We discovered that salamander limb ECM has a position-specific ability to either inhibit regeneration or induce de novo limb structure, and that this difference is dependent on heparan sulfates that are associated with differential expression of heparan sulfate sulfotransferases. We also discovered that an artificial ECM containing only heparan sulfate was sufficient to induce de novo limb pattern in salamander limb regeneration. Finally, ECM from mouse limbs is capable of inducing limb pattern in axolotl blastemas in a position-specific, developmental-stage-specific, and heparan sulfate-dependent manner. This study demonstrates a mechanism for positional information in regeneration and establishes a crucial functional link between salamander regeneration and mammals.

  16. Regulation of Axolotl (Ambystoma mexicanum) Limb Blastema Cell Proliferation by Nerves and BMP2 in Organotypic Slice Culture.

    Science.gov (United States)

    Lehrberg, Jeffrey; Gardiner, David M

    2015-01-01

    We have modified and optimized the technique of organotypic slice culture in order to study the mechanisms regulating growth and pattern formation in regenerating axolotl limb blastemas. Blastema cells maintain many of the behaviors that are characteristic of blastemas in vivo when cultured as slices in vitro, including rates of proliferation that are comparable to what has been reported in vivo. Because the blastema slices can be cultured in basal medium without fetal bovine serum, it was possible to test the response of blastema cells to signaling molecules present in serum, as well as those produced by nerves. We also were able to investigate the response of blastema cells to experimentally regulated changes in BMP signaling. Blastema cells responded to all of these signals by increasing the rate of proliferation and the level of expression of the blastema marker gene, Prrx-1. The organotypic slice culture model provides the opportunity to identify and characterize the spatial and temporal co-regulation of pathways in order to induce and enhance a regenerative response.

  17. Regulation of Axolotl (Ambystoma mexicanum Limb Blastema Cell Proliferation by Nerves and BMP2 in Organotypic Slice Culture.

    Directory of Open Access Journals (Sweden)

    Jeffrey Lehrberg

    Full Text Available We have modified and optimized the technique of organotypic slice culture in order to study the mechanisms regulating growth and pattern formation in regenerating axolotl limb blastemas. Blastema cells maintain many of the behaviors that are characteristic of blastemas in vivo when cultured as slices in vitro, including rates of proliferation that are comparable to what has been reported in vivo. Because the blastema slices can be cultured in basal medium without fetal bovine serum, it was possible to test the response of blastema cells to signaling molecules present in serum, as well as those produced by nerves. We also were able to investigate the response of blastema cells to experimentally regulated changes in BMP signaling. Blastema cells responded to all of these signals by increasing the rate of proliferation and the level of expression of the blastema marker gene, Prrx-1. The organotypic slice culture model provides the opportunity to identify and characterize the spatial and temporal co-regulation of pathways in order to induce and enhance a regenerative response.

  18. Localization of amylin-like immunoreactivity in melanocyte-stimulating hormone-containing cells of the pars intermedia but not those of the pars distalis in the axolotl (Ambystoma mexicanum) pituitary.

    Science.gov (United States)

    Suzuki, Hirohumi; Yamamoto, Toshiharu

    2016-04-01

    Immunohistochemical techniques were employed to investigate the distribution of amylin-like immunoreactivity in the axolotl (Ambystoma mexicanum) pituitary. Amylin-immunoreactive cells were observed in the pars intermedia, and these cells were found to be immunoreactive for α-melanocyte-stimulating hormone (αMSH) as well. In contrast, αMSH-immunoreactive cells in the pars distalis were immuno-negaitive for amylin. These light microscopic findings were confirmed by immunoelectron microscopy. Amylin-immunoreactive signals were located on the haloes of presumable secretory granules in association with αMSH-immunoreactive signals in the amylin-positive cells. However, in the pars distalis, the αMSH-positive cells did not contain amylin-immunoreactive secretory granules. Western blot analysis of axolotl pituitary extracts revealed the labeling of a protein band at approximately 10.5-kDa by the anti-rat amylin serum, which was not labeled by the anti-αMSH antibody. These findings indicate that amylin secreted from MSH-producing cells in the pars intermedia may modulate MSH secretion in an autocrine fashion and may participate in MSH functions such as fatty homeostasis together with MSH. Copyright © 2016 Elsevier GmbH. All rights reserved.

  19. The Mexican Axolotl in Schools

    Science.gov (United States)

    Thomas, R. M.

    1976-01-01

    Suggests and describes laboratory activities in which the Mexican axolotl (Ambystoma mexicanum Shaw) is used, including experiments in embryology and early development, growth and regeneration, neoteny and metamorphosis, genetics and coloration, anatomy and physiology, and behavior. Discusses care and maintenance of animals. (CS)

  20. The yeast two hybrid system in a screen for proteins interacting with axolotl (Ambystoma mexicanum) Msx1 during early limb regeneration.

    Science.gov (United States)

    Abuqarn, Mehtap; Allmeling, Christina; Amshoff, Inga; Menger, Bjoern; Nasser, Inas; Vogt, Peter M; Reimers, Kerstin

    2011-07-01

    Urodele amphibians are exceptional in their ability to regenerate complex body structures such as limbs. Limb regeneration depends on a process called dedifferentiation. Under an inductive wound epidermis terminally differentiated cells transform to pluripotent progenitor cells that coordinately proliferate and eventually redifferentiate to form the new appendage. Recent studies have developed molecular models integrating a set of genes that might have important functions in the control of regenerative cellular plasticity. Among them is Msx1, which induced dedifferentiation in mammalian myotubes in vitro. Herein, we screened for interaction partners of axolotl Msx1 using a yeast two hybrid system. A two hybrid cDNA library of 5-day-old wound epidermis and underlying tissue containing more than 2×10⁶ cDNAs was constructed and used in the screen. 34 resulting cDNA clones were isolated and sequenced. We then compared sequences of the isolated clones to annotated EST contigs of the Salamander EST database (BLASTn) to identify presumptive orthologs. We subsequently searched all no-hit clone sequences against non redundant NCBI sequence databases using BLASTx. It is the first time, that the yeast two hybrid system was adapted to the axolotl animal model and successfully used in a screen for proteins interacting with Msx1 in the context of amphibian limb regeneration. 2011 Elsevier B.V. All rights reserved.

  1. Immunocytochemical localization and immunochemical characterization of an insulin-related peptide in the pancreas of the urodele amphibian, Ambystoma mexicanum

    DEFF Research Database (Denmark)

    Hansen, G N; Hansen, B L; Jørgensen, P N

    1989-01-01

    The pancreas of the axolotl, Ambystoma mexicanum, was investigated by immunocytochemical methods for the presence of immunoreactivity to a number of antisera raised against mammalian insulins. All anti-insulin antisera tested revealed substantial amounts of reaction products confined solely...

  2. MRI tracking of SPIO labelled stem cells in a true regenerative environment, the regenerating limb of the axolotl

    DEFF Research Database (Denmark)

    Lauridsen, Henrik; Foldager, Casper Bindzus; Hagensen, Mette

    are generally restricted by their limited regenerative potential. Conversely, excellent animal models for regenerative studies exist in lower vertebrates such as the urodele amphibians (salamanders and newts), exemplified in the iconic Mexican axolotl (Ambystoma mexicanum) capable of regenerating whole limbs...

  3. Profiling neurotransmitter receptor expression in the Ambystoma mexicanum brain.

    Science.gov (United States)

    Reyes-Ruiz, Jorge Mauricio; Limon, Agenor; Korn, Matthew J; Nakamura, Paul A; Shirkey, Nicole J; Wong, Jamie K; Miledi, Ricardo

    2013-03-22

    Ability to regenerate limbs and central nervous system (CNS) is unique to few vertebrates, most notably the axolotl (Ambystoma sp.). However, despite the fact the neurotransmitter receptors are involved in axonal regeneration, little is known regarding its expression profile. In this project, RT-PCR and qPCR were performed to gain insight into the neurotransmitter receptors present in Ambystoma. Its functional ability was studied by expressing axolotl receptors in Xenopus laevis oocytes by either injection of mRNA or by direct microtransplantation of brain membranes. Oocytes injected with axolotl mRNA expressed ionotropic receptors activated by GABA, aspartate+glycine and kainate, as well as metabotropic receptors activated by acetylcholine and glutamate. Interestingly, we did not see responses following the application of serotonin. Membranes from the axolotl brain were efficiently microtransplanted into Xenopus oocytes and two types of native GABA receptors that differed in the temporal course of their responses and affinities to GABA were observed. Results of this study are necessary for further characterization of axolotl neurotransmitter receptors and may be useful for guiding experiments aimed at understanding activity-dependant limb and CNS regeneration. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. Propofol (2,6-diisopropylphenol) is an applicable immersion anesthetic in the axolotl with potential uses in hemodynamic and neurophysiological experiments

    DEFF Research Database (Denmark)

    Thygesen, Mathias; Rasmussen, Mikkel Mylius; Madsen, Jesper Guldsmed

    2017-01-01

    The Mexican axolotl (Ambystoma mexicanum) is an important model species in regenerative biology. Traditionally, axolotls are anesthetized using benzocaine or MS-222, both of which act to inhibit voltage gated sodium channels thereby preventing action potential propagation. In some neurophysiologi......The Mexican axolotl (Ambystoma mexicanum) is an important model species in regenerative biology. Traditionally, axolotls are anesthetized using benzocaine or MS-222, both of which act to inhibit voltage gated sodium channels thereby preventing action potential propagation. In some...... neurophysiological experiments this is not desirable; therefore we tested propofol as an alternative anesthetic in the axolotl. We evaluated benzocaine, MS-222, and propofol's cardiovascular effects, effects on action potential propagation in the spinal cord, and gross limb regenerative effects. We found...

  5. Hyperbaric oxygen therapy in a true regenerative environment, the regenerating limb of the axolotl

    DEFF Research Database (Denmark)

    Hansen, Kasper; Lauridsen, Henrik; Pedersen, Michael

    2012-01-01

    vertebrates such as the urodele amphibians (salamanders and newts), are excellent animal models for regenerative studies. The iconic Mexican axolotl (Ambystoma mexicanum) is capable of regenerating whole limbs, tail, jaw, and many inner organs, by dedifferentiation of cells to form a blastema (collection...

  6. ISOLATION AND CHARACTERIZATION OF AXOLOTL NPDC-1 AND ITS EFFECTS ON RETINOIC ACID RECEPTOR SIGNALING

    Science.gov (United States)

    Theodosiou, Maria; Monaghan, James R; Spencer, Michael L; Voss, S Randal; Noonan, Daniel J

    2009-01-01

    Retinoic acid, a key morphogen in early vertebrate development and tissue regeneration, mediates its effects through the binding of receptors that act as ligand-induced transcription factors. These binding events function to recruit an array of transcription co-regulatory proteins to specific gene promoters. One such co-regulatory protein, neuronal proliferation and differentiation control-1 (NPDC-1), is broadly expressed during mammalian development and functions as an in vitro repressor of retinoic acid receptor (RAR)-mediated transcription. To obtain comparative and developmental insights about NPDC-1 function, we cloned the axolotl (Ambystoma mexicanum) orthologue and measured transcript abundances among tissues sampled during the embryonic and juvenile phases of development, and also during spinal cord regeneration. Structurally, the axolotl orthologue of NPDC-1 retained sequence identity to mammalian sequences in all functional domains. Functionally, we observed that axolotl NPDC-1 mRNA expression peaked late in embryogenesis, with highest levels of expression occurring during the time of limb development, a process regulated by retinoic acid signaling. Also similar to what has been observed in mammals, axolotl NPDC-1 directly interacts with axolotl RAR, modulates axolotl RAR DNA binding, and represses cell proliferation and axolotl RAR-mediated gene transcription. These data justify axolotl as a model to further investigate NPDC-1 and its role in regulating retinoic acid signaling. PMID:17331771

  7. Functional characterization of the vertebrate primary ureter: Structure and ion transport mechanisms of the pronephric duct in axolotl larvae (Amphibia)

    DEFF Research Database (Denmark)

    Haugan, Birgitte M; Halberg, Kenneth Agerlin; Jespersen, Åse

    2010-01-01

    whether the duct is involved in urine modification using larvae of the freshwater amphibian Ambystoma mexicanum (axolotl) as model. Results We investigated structural as well as physiological properties of the pronephric duct. The key elements of our methodology were: using histology, light...

  8. Activation of germline-specific genes is required for limb regeneration in the Mexican axolotl

    OpenAIRE

    Zhu, Wei; Pao, Gerald M; Satoh, Akira; Cummings, Gillian; Monaghan, James R; Harkins, Timothy T; Bryant, Susan V; Voss, S Randal; Gardiner, David M; Hunter, Tony

    2012-01-01

    The capacity for tissue and organ regeneration in humans is dwarfed by comparison to that of salamanders. Emerging evidence suggests that mechanisms learned from the early phase of salamander limb regeneration-wound healing, cellular dedifferentiation and blastemal formation-will reveal therapeutic approaches for tissue regeneration in humans. Here we describe a unique transcriptional fingerprint of regenerating limb tissue in the Mexican axolotl (Ambystoma mexicanum) that is indicative of ce...

  9. DiI Perfusion as a Method for Vascular Visualization in Ambystoma mexicanum.

    Science.gov (United States)

    Saltman, Anna J; Barakat, May; Bryant, Donald M; Brodovskaya, Anastasia; Whited, Jessica L

    2017-06-16

    Perfusion techniques have been used for centuries to visualize the circulation of tissues. Axolotl (Ambystoma mexicanum) is a species of salamander that has emerged as an essential model for regeneration studies. Little is known about how revascularization occurs in the context of regeneration in these animals. Here we report a simple method for visualization of the vasculature in axolotl via perfusion of 1,1'-Dioctadecy-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI). DiI is a lipophilic carbocyanine dye that inserts into the plasma membrane of endothelial cells instantaneously. Perfusion is done using a peristaltic pump such that DiI enters the circulation through the aorta. During perfusion, dye flows through the axolotl's blood vessels and incorporates into the lipid bilayer of vascular endothelial cells upon contact. The perfusion procedure takes approximately one hour for an eight-inch axolotl. Immediately after perfusion with DiI, the axolotl can be visualized with a confocal fluorescent microscope. The DiI emits light in the red-orange range when excited with a green fluorescent filter. This DiI perfusion procedure can be used to visualize the vascular structure of axolotls or to demonstrate patterns of revascularization in regenerating tissues.

  10. A histological atlas of the tissues and organs of neotenic and metamorphosed axolotl.

    Science.gov (United States)

    Demircan, Turan; İlhan, Ayşe Elif; Aytürk, Nilüfer; Yıldırım, Berna; Öztürk, Gürkan; Keskin, İlknur

    2016-09-01

    Axolotl (Ambystoma Mexicanum) has been emerging as a promising model in stem cell and regeneration researches due to its exceptional regenerative capacity. Although it represents lifelong lasting neoteny, induction to metamorphosis with thyroid hormones (THs) treatment advances the utilization of Axolotl in various studies. It has been reported that amphibians undergo anatomical and histological remodeling during metamorphosis and this transformation is crucial for adaptation to terrestrial conditions. However, there is no comprehensive histological investigation regarding the morphological alterations of Axolotl organs and tissues throughout the metamorphosis. Here, we reveal the histological differences or resemblances between the neotenic and metamorphic axolotl tissues. In order to examine structural features and cellular organization of Axolotl organs, we performed Hematoxylin & Eosin, Luxol-Fast blue, Masson's trichrome, Alcian blue, Orcein and Weigart's staining. Stained samples from brain, gallbladder, heart, intestine, liver, lung, muscle, skin, spleen, stomach, tail, tongue and vessel were analyzed under the light microscope. Our findings contribute to the validation of the link between newly acquired functions and structural changes of tissues and organs as observed in tail, skin, gallbladder and spleen. We believe that this descriptive work provides new insights for a better histological understanding of both neotenic and metamorphic Axolotl tissues. Copyright © 2016 Elsevier GmbH. All rights reserved.

  11. Experimentally induced metamorphosis in axolotls reduces regenerative rate and fidelity

    Science.gov (United States)

    Stier, Adrian C.; Michonneau, François; Smith, Matthew D.; Pasch, Bret; Maden, Malcolm

    2014-01-01

    Abstract While most tetrapods are unable to regenerate severed body parts, amphibians display a remarkable ability to regenerate an array of structures. Frogs can regenerate appendages as larva, but they lose this ability around metamorphosis. In contrast, salamanders regenerate appendages as larva, juveniles, and adults. However, the extent to which fundamental traits (e.g., metamorphosis, body size, aging, etc.) restrict regenerative ability remains contentious. Here we utilize the ability of normally paedomorphic adult axolotls (Ambystoma mexicanum) to undergo induced metamorphosis by thyroxine exposure to test how metamorphosis and body size affects regeneration in age‐matched paedomorphic and metamorphic individuals. We show that body size does not affect regeneration in adult axolotls, but metamorphosis causes a twofold reduction in regeneration rate, and lead to carpal and digit malformations. Furthermore, we find evidence that metamorphic blastemal cells may take longer to traverse the cell cycle and display a lower proliferative rate. This study identifies the axolotl as a powerful system to study how metamorphosis restricts regeneration independently of developmental stage, body size, and age; and more broadly how metamorphosis affects tissue‐specific changes. PMID:27499857

  12. Propofol (2,6-diisopropylphenol) is an applicable immersion anesthetic in the axolotl with potential uses in hemodynamic and neurophysiological experiments

    DEFF Research Database (Denmark)

    Thygesen, Mathias; Rasmussen, Mikkel Mylius; Madsen, Jesper Guldsmed

    2017-01-01

    The Mexican axolotl (Ambystoma mexicanum) is an important model species in regenerative biology. Traditionally, axolotls are anesthetized using benzocaine or MS-222, both of which act to inhibit voltage gated sodium channels thereby preventing action potential propagation. In some...... neurophysiological experiments this is not desirable; therefore we tested propofol as an alternative anesthetic in the axolotl. We evaluated benzocaine, MS-222, and propofol's cardiovascular effects, effects on action potential propagation in the spinal cord, and gross limb regenerative effects. We found...... that propofol is applicable as a general anesthetic in the axolotl allowing for neurophysiological experiments and yielding a stable anesthesia with significantly less cardiovascular effect than both benzocaine and MS-222. Additionally, propofol did not affect gross limb regeneration. In conclusion we suggest...

  13. The Hungry Season

    African Journals Online (AJOL)

    start to go some way towards addressing this fundamental question. A delightful animation of The Hungry Season, commissioned by Leonie Joubert and funded by the University of Cape Town's Criminology. Department and the Embassy of Finland, is available online at http://www.youtube.com/ watch?v=iX77NZttLKo.

  14. Comparative Analysis of Cartilage Marker Gene Expression Patterns during Axolotl and Xenopus Limb Regeneration.

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    Kazumasa Mitogawa

    Full Text Available Axolotls (Ambystoma mexicanum can completely regenerate lost limbs, whereas Xenopus laevis frogs cannot. During limb regeneration, a blastema is first formed at the amputation plane. It is thought that this regeneration blastema forms a limb by mechanisms similar to those of a developing embryonic limb bud. Furthermore, Xenopus laevis frogs can form a blastema after amputation; however, the blastema results in a terminal cone-shaped cartilaginous structure called a "spike." The causes of this patterning defect in Xenopus frog limb regeneration were explored. We hypothesized that differences in chondrogenesis may underlie the patterning defect. Thus, we focused on chondrogenesis. Chondrogenesis marker genes, type I and type II collagen, were compared in regenerative and nonregenerative environments. There were marked differences between axolotls and Xenopus in the expression pattern of these chondrogenesis-associated genes. The relative deficit in the chondrogenic capacity of Xenopus blastema cells may account for the absence of total limb regenerative capacity.

  15. Germline Transgenic Methods for Tracking Cells and Testing Gene Function during Regeneration in the Axolotl

    Science.gov (United States)

    Khattak, Shahryar; Schuez, Maritta; Richter, Tobias; Knapp, Dunja; Haigo, Saori L.; Sandoval-Guzmán, Tatiana; Hradlikova, Kristyna; Duemmler, Annett; Kerney, Ryan; Tanaka, Elly M.

    2013-01-01

    The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cell-cycle inhibitor p16INK4a, which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible. PMID:24052945

  16. Highly efficient targeted mutagenesis in axolotl using Cas9 RNA-guided nuclease

    Science.gov (United States)

    Flowers, G. Parker; Timberlake, Andrew T.; Mclean, Kaitlin C.; Monaghan, James R.; Crews, Craig M.

    2014-01-01

    Among tetrapods, only urodele salamanders, such as the axolotl Ambystoma mexicanum, can completely regenerate limbs as adults. The mystery of why salamanders, but not other animals, possess this ability has for generations captivated scientists seeking to induce this phenomenon in other vertebrates. Although many recent advances in molecular biology have allowed limb regeneration and tissue repair in the axolotl to be investigated in increasing detail, the molecular toolkit for the study of this process has been limited. Here, we report that the CRISPR-Cas9 RNA-guided nuclease system can efficiently create mutations at targeted sites within the axolotl genome. We identify individual animals treated with RNA-guided nucleases that have mutation frequencies close to 100% at targeted sites. We employ this technique to completely functionally ablate EGFP expression in transgenic animals and recapitulate developmental phenotypes produced by loss of the conserved gene brachyury. Thus, this advance allows a reverse genetic approach in the axolotl and will undoubtedly provide invaluable insight into the mechanisms of salamanders' unique regenerative ability. PMID:24764077

  17. Role of Myofibril-Inducing RNA in cardiac TnT expression in developing Mexican axolotl

    Science.gov (United States)

    Sferrazza, Gian-Franco; Zhang, Chi; Jia, Pingping; Lemanski, Sharon L.; Athauda, Gagani; Stassi, Alyssa; Halager, Kristine; Maier, Jennifer A.; Rueda-de-Leon, Elena; Gupta, Amit; Dube, Syamalima; Huang, Xupei; Prentice, Howard M.; Dube, Dipak K.; Lemanski, Larry F.

    2007-01-01

    The Mexican axolotl, Ambystoma mexicanum, has been a useful animal model to study heart development and cardiac myofibrillogenesis. A naturally-occurring recessive mutant, gene “c”, for cardiac non-function in the Mexican axolotl causes a failure of myofibrillogenesis due to a lack of tropomyosin expression in homozygous mutant (c/c) embryonic hearts.. Myofibril-Inducing RNA (MIR) rescues mutant hearts in vitro by promoting tropomyosin expression and myofibril formation thereafter. We have studied the effect of MIR on the expression of various isoforms of cardiac Troponin-T (cTnT), a component of the thin filament that binds with tropomyosin. Four alternatively spliced cTnT isoforms have been characterized from developing axolotl heart. The expression of various cTnT isoforms in normal, mutant, and mutant hearts corrected with MIR, is evaluated by real-time RT-PCR using isoform specific primer pairs; MIR affects the total transcription as well as the splicing of the cTnT in axolotl heart PMID:17408593

  18. Identification of Conserved and Novel MicroRNAs during Tail Regeneration in the Mexican Axolotl

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    Micah D. Gearhart

    2015-09-01

    Full Text Available The Mexican axolotl salamander (Ambystoma mexicanum is one member of a select group of vertebrate animals that have retained the amazing ability to regenerate multiple body parts. In addition to being an important model system for regeneration, the axolotl has also contributed extensively to studies of basic development. While many genes known to play key roles during development have now been implicated in various forms of regeneration, much of the regulatory apparatus controlling the underlying molecular circuitry remains unknown. In recent years, microRNAs have been identified as key regulators of gene expression during development, in many diseases and also, increasingly, in regeneration. Here, we have used deep sequencing combined with qRT-PCR to undertake a comprehensive identification of microRNAs involved in regulating regeneration in the axolotl. Specifically, among the microRNAs that we have found to be expressed in axolotl tissues, we have identified 4564 microRNA families known to be widely conserved among vertebrates, as well as 59,811 reads of putative novel microRNAs. These findings support the hypothesis that microRNAs play key roles in managing the precise spatial and temporal patterns of gene expression that ensures the correct regeneration of missing tissues.

  19. Efficient gene knockin in axolotl and its use to test the role of satellite cells in limb regeneration.

    Science.gov (United States)

    Fei, Ji-Feng; Schuez, Maritta; Knapp, Dunja; Taniguchi, Yuka; Drechsel, David N; Tanaka, Elly M

    2017-11-21

    Salamanders exhibit extensive regenerative capacities and serve as a unique model in regeneration research. However, due to the lack of targeted gene knockin approaches, it has been difficult to label and manipulate some of the cell populations that are crucial for understanding the mechanisms underlying regeneration. Here we have established highly efficient gene knockin approaches in the axolotl ( Ambystoma mexicanum ) based on the CRISPR/Cas9 technology. Using a homology-independent method, we successfully inserted both the Cherry reporter gene and a larger membrane-tagged Cherry-ER T2 -Cre-ER T2 (∼5-kb) cassette into axolotl Sox2 and Pax7 genomic loci. Depending on the size of the DNA fragments for integration, 5-15% of the F0 transgenic axolotl are positive for the transgene. Using these techniques, we have labeled and traced the PAX7-positive satellite cells as a major source contributing to myogenesis during axolotl limb regeneration. Our work brings a key genetic tool to molecular and cellular studies of axolotl regeneration.

  20. Musashi and Plasticity of Xenopus and Axolotl Spinal Cord Ependymal Cells

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    Ellen A. G. Chernoff

    2018-02-01

    Full Text Available The differentiated state of spinal cord ependymal cells in regeneration-competent amphibians varies between a constitutively active state in what is essentially a developing organism, the tadpole of the frog Xenopus laevis, and a quiescent, activatable state in a slowly growing adult salamander Ambystoma mexicanum, the Axolotl. Ependymal cells are epithelial in intact spinal cord of all vertebrates. After transection, body region ependymal epithelium in both Xenopus and the Axolotl disorganizes for regenerative outgrowth (gap replacement. Injury-reactive ependymal cells serve as a stem/progenitor cell population in regeneration and reconstruct the central canal. Expression patterns of mRNA and protein for the stem/progenitor cell-maintenance Notch signaling pathway mRNA-binding protein Musashi (msi change with life stage and regeneration competence. Msi-1 is missing (immunohistochemistry, or at very low levels (polymerase chain reaction, PCR, in both intact regeneration-competent adult Axolotl cord and intact non-regeneration-competent Xenopus tadpole (Nieuwkoop and Faber stage 62+, NF 62+. The critical correlation for successful regeneration is msi-1 expression/upregulation after injury in the ependymal outgrowth and stump-region ependymal cells. msi-1 and msi-2 isoforms were cloned for the Axolotl as well as previously unknown isoforms of Xenopus msi-2. Intact Xenopus spinal cord ependymal cells show a loss of msi-1 expression between regeneration-competent (NF 50–53 and non-regenerating stages (NF 62+ and in post-metamorphosis froglets, while msi-2 displays a lower molecular weight isoform in non-regenerating cord. In the Axolotl, embryos and juveniles maintain Msi-1 expression in the intact cord. In the adult Axolotl, Msi-1 is absent, but upregulates after injury. Msi-2 levels are more variable among Axolotl life stages: rising between late tailbud embryos and juveniles and decreasing in adult cord. Cultures of regeneration

  1. Musashi and Plasticity of Xenopus and Axolotl Spinal Cord Ependymal Cells

    Science.gov (United States)

    Chernoff, Ellen A. G.; Sato, Kazuna; Salfity, Hai V. N.; Sarria, Deborah A.; Belecky-Adams, Teri

    2018-01-01

    The differentiated state of spinal cord ependymal cells in regeneration-competent amphibians varies between a constitutively active state in what is essentially a developing organism, the tadpole of the frog Xenopus laevis, and a quiescent, activatable state in a slowly growing adult salamander Ambystoma mexicanum, the Axolotl. Ependymal cells are epithelial in intact spinal cord of all vertebrates. After transection, body region ependymal epithelium in both Xenopus and the Axolotl disorganizes for regenerative outgrowth (gap replacement). Injury-reactive ependymal cells serve as a stem/progenitor cell population in regeneration and reconstruct the central canal. Expression patterns of mRNA and protein for the stem/progenitor cell-maintenance Notch signaling pathway mRNA-binding protein Musashi (msi) change with life stage and regeneration competence. Msi-1 is missing (immunohistochemistry), or at very low levels (polymerase chain reaction, PCR), in both intact regeneration-competent adult Axolotl cord and intact non-regeneration-competent Xenopus tadpole (Nieuwkoop and Faber stage 62+, NF 62+). The critical correlation for successful regeneration is msi-1 expression/upregulation after injury in the ependymal outgrowth and stump-region ependymal cells. msi-1 and msi-2 isoforms were cloned for the Axolotl as well as previously unknown isoforms of Xenopus msi-2. Intact Xenopus spinal cord ependymal cells show a loss of msi-1 expression between regeneration-competent (NF 50–53) and non-regenerating stages (NF 62+) and in post-metamorphosis froglets, while msi-2 displays a lower molecular weight isoform in non-regenerating cord. In the Axolotl, embryos and juveniles maintain Msi-1 expression in the intact cord. In the adult Axolotl, Msi-1 is absent, but upregulates after injury. Msi-2 levels are more variable among Axolotl life stages: rising between late tailbud embryos and juveniles and decreasing in adult cord. Cultures of regeneration-competent Xenopus tadpole

  2. Myofibril-Inducing RNA (MIR is essential for tropomyosin expression and myofibrillogenesis in axolotl hearts

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    Lemanski Sharon L

    2009-09-01

    Full Text Available Abstract The Mexican axolotl, Ambystoma mexicanum, carries the naturally-occurring recessive mutant gene 'c' that results in a failure of homozygous (c/c embryos to form hearts that beat because of an absence of organized myofibrils. Our previous studies have shown that a noncoding RNA, Myofibril-Inducing RNA (MIR, is capable of promoting myofibrillogenesis and heart beating in the mutant (c/c axolotls. The present study demonstrates that the MIR gene is essential for tropomyosin (TM expression in axolotl hearts during development. Gene expression studies show that mRNA expression of various tropomyosin isoforms in untreated mutant hearts and in normal hearts knocked down with double-stranded MIR (dsMIR are similar to untreated normal. However, at the protein level, selected tropomyosin isoforms are significantly reduced in mutant and dsMIR treated normal hearts. These results suggest that MIR is involved in controlling the translation or post-translation of various TM isoforms and subsequently of regulating cardiac contractility.

  3. Neuregulin-1 signaling is essential for nerve-dependent axolotl limb regeneration.

    Science.gov (United States)

    Farkas, Johanna E; Freitas, Polina D; Bryant, Donald M; Whited, Jessica L; Monaghan, James R

    2016-08-01

    The Mexican axolotl (Ambystoma mexicanum) is capable of fully regenerating amputated limbs, but denervation of the limb inhibits the formation of the post-injury proliferative mass called the blastema. The molecular basis behind this phenomenon remains poorly understood, but previous studies have suggested that nerves support regeneration via the secretion of essential growth-promoting factors. An essential nerve-derived factor must be found in the blastema, capable of rescuing regeneration in denervated limbs, and its inhibition must prevent regeneration. Here, we show that the neuronally secreted protein Neuregulin-1 (NRG1) fulfills all these criteria in the axolotl. Immunohistochemistry and in situ hybridization of NRG1 and its active receptor ErbB2 revealed that they are expressed in regenerating blastemas but lost upon denervation. NRG1 was localized to the wound epithelium prior to blastema formation and was later strongly expressed in proliferating blastemal cells. Supplementation by implantation of NRG1-soaked beads rescued regeneration to digits in denervated limbs, and pharmacological inhibition of NRG1 signaling reduced cell proliferation, blocked blastema formation and induced aberrant collagen deposition in fully innervated limbs. Taken together, our results show that nerve-dependent NRG1/ErbB2 signaling promotes blastemal proliferation in the regenerating limb and may play an essential role in blastema formation, thus providing insight into the longstanding question of why nerves are required for axolotl limb regeneration. © 2016. Published by The Company of Biologists Ltd.

  4. Hungry pigeons make suboptimal choices, less hungry pigeons do not.

    Science.gov (United States)

    Laude, Jennifer R; Pattison, Kristina F; Zentall, Thomas R

    2012-10-01

    Hungry animals will often choose suboptimally by being attracted to reliable signals for food that occur infrequently (they gamble) over less reliable signals for food that occur more often. That is, pigeons prefer an option that 50 % of the time provides them with a reliable signal for the appearance of food but 50 % of the time provides them with a reliable signal for the absence of food (overall 50 % reinforcement) over an alternative that always provides them with a signal for the appearance of food 75 % of the time (overall 75 % reinforcement). The pigeons appear to choose impulsively for the possibility of obtaining the reliable signal for reinforcement. There is evidence that greater hunger is associated with greater impulsivity. We tested the hypothesis that if the pigeons were less hungry, they would be less impulsive and, thus, would choose more optimally (i.e., on the basis of the overall probability of reinforcement). We found that hungry pigeons choose the 50 % reinforcement alternative suboptimally but less hungry pigeons prefer the more optimal 75 % reinforcement. Paradoxically, pigeons that needed the food more received less of it. These findings have implications for how level of motivation may also affect human suboptimal choice (e.g., purchase of lottery tickets and playing slot machines).

  5. Generation of axolotl hematopoietic chimeras

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    David Lopez

    2015-02-01

    Full Text Available Wound repair is an extremely complex process that requires precise coordination between various cell types including immune cells.  Unfortunately, in mammals this usually results in scar formation instead of restoration of the original fully functional tissue, otherwise known as regeneration.  Various animal models like frogs and salamanders are currently being studied to determine the intracellular and intercellular pathways, controlled by gene expression, that elicit cell proliferation, differentiation, and migration of cells during regenerative healing.  Now, the necessary genetic tools to map regenerative pathways are becoming available for the axolotl salamander, thus allowing comparative studies between scarring and regeneration.  Here, we describe in detail three methods to produce axolotl hematopoietic cell-tagged chimeras for the study of hematopoiesis and regeneration.

  6. An Aryl Hydrocarbon Receptor from the Salamander Ambystoma mexicanum Exhibits Low Sensitivity to 2,3,7,8-Tetrachlorodibenzo-p-dioxin.

    Science.gov (United States)

    Shoots, Jenny; Fraccalvieri, Domenico; Franks, Diana G; Denison, Michael S; Hahn, Mark E; Bonati, Laura; Powell, Wade H

    2015-06-02

    Structural features of the aryl hydrocarbon receptor (AHR) can underlie species- and population-specific differences in its affinity for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). These differences often explain variations in TCDD toxicity. Frogs are relatively insensitive to dioxin, and Xenopus AHRs bind TCDD with low affinity. Weak TCDD binding results from the combination of three residues in the ligand-binding domain: A354 and A370, and N325. Here we sought to determine whether this mechanism of weak TCDD binding is shared by other amphibian AHRs. We isolated an AHR cDNA from the Mexican axolotl (Ambystoma mexicanum). The encoded polypeptide contains identical residues at positions that confer low TCDD affinity to X. laevis AHRs (A364, A380, and N335), and homology modeling predicts they protrude into the binding cavity. Axolotl AHR bound one-tenth the TCDD of mouse AHR in velocity sedimentation analysis, and in transactivation assays, the EC50 for TCDD was 23 nM, similar to X. laevis AHR1β (27 nM) and greater than AHR containing the mouse ligand-binding domain (0.08 nM). Sequence, modeled structure, and function indicate that axolotl AHR binds TCDD weakly, predicting that A. mexicanum lacks sensitivity toTCDD toxicity. We hypothesize that this characteristic of axolotl and Xenopus AHRs arose in a common ancestor of the Caudata and Anura.

  7. Electron microscopy of the amphibian model systems Xenopus laevis and Ambystoma mexicanum.

    Science.gov (United States)

    Kurth, Thomas; Berger, Jürgen; Wilsch-Bräuninger, Michaela; Kretschmar, Susanne; Cerny, Robert; Schwarz, Heinz; Löfberg, Jan; Piendl, Thomas; Epperlein, Hans H

    2010-01-01

    In this chapter we provide a set of different protocols for the ultrastructural analysis of amphibian (Xenopus, axolotl) tissues, mostly of embryonic origin. For Xenopus these methods include: (1) embedding gastrulae and tailbud embryos into Spurr's resin for TEM, (2) post-embedding labeling of methacrylate (K4M) and cryosections through adult and embryonic epithelia for correlative LM and TEM, and (3) pre-embedding labeling of embryonic tissues with silver-enhanced nanogold. For the axolotl (Ambystoma mexicanum) we present the following methods: (1) SEM of migrating neural crest (NC) cells; (2) SEM and TEM of extracellular matrix (ECM) material; (3) Cryo-SEM of extracellular matrix (ECM) material after cryoimmobilization; and (4) TEM analysis of hyaluronan using high-pressure freezing and HABP labeling. These methods provide exemplary approaches for a variety of questions in the field of amphibian development and regeneration, and focus on cell biological issues that can only be answered with fine structural imaging methods, such as electron microscopy. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. De novo transcriptome sequencing of axolotl blastema for identification of differentially expressed genes during limb regeneration

    Science.gov (United States)

    2013-01-01

    Background Salamanders are unique among vertebrates in their ability to completely regenerate amputated limbs through the mediation of blastema cells located at the stump ends. This regeneration is nerve-dependent because blastema formation and regeneration does not occur after limb denervation. To obtain the genomic information of blastema tissues, de novo transcriptomes from both blastema tissues and denervated stump ends of Ambystoma mexicanum (axolotls) 14 days post-amputation were sequenced and compared using Solexa DNA sequencing. Results The sequencing done for this study produced 40,688,892 reads that were assembled into 307,345 transcribed sequences. The N50 of transcribed sequence length was 562 bases. A similarity search with known proteins identified 39,200 different genes to be expressed during limb regeneration with a cut-off E-value exceeding 10-5. We annotated assembled sequences by using gene descriptions, gene ontology, and clusters of orthologous group terms. Targeted searches using these annotations showed that the majority of the genes were in the categories of essential metabolic pathways, transcription factors and conserved signaling pathways, and novel candidate genes for regenerative processes. We discovered and confirmed numerous sequences of the candidate genes by using quantitative polymerase chain reaction and in situ hybridization. Conclusion The results of this study demonstrate that de novo transcriptome sequencing allows gene expression analysis in a species lacking genome information and provides the most comprehensive mRNA sequence resources for axolotls. The characterization of the axolotl transcriptome can help elucidate the molecular mechanisms underlying blastema formation during limb regeneration. PMID:23815514

  9. Microarray Analysis of microRNA Expression during Axolotl Limb Regeneration

    Science.gov (United States)

    Holman, Edna C.; Campbell, Leah J.; Hines, John; Crews, Craig M.

    2012-01-01

    Among vertebrates, salamanders stand out for their remarkable capacity to quickly regrow a myriad of tissues and organs after injury or amputation. The limb regeneration process in axolotls (Ambystoma mexicanum) has been well studied for decades at the cell-tissue level. While several developmental genes are known to be reactivated during this epimorphic process, less is known about the role of microRNAs in urodele amphibian limb regeneration. Given the compelling evidence that many microRNAs tightly regulate cell fate and morphogenetic processes through development and adulthood by modulating the expression (or re-expression) of developmental genes, we investigated the possibility that microRNA levels change during limb regeneration. Using two different microarray platforms to compare the axolotl microRNA expression between mid-bud limb regenerating blastemas and non-regenerating stump tissues, we found that miR-21 was overexpressed in mid-bud blastemas compared to stump tissue. Mature A. mexicanum (“Amex”) miR-21 was detected in axolotl RNA by Northern blot and differential expression of Amex-miR-21 in blastema versus stump was confirmed by quantitative RT-PCR. We identified the Amex Jagged1 as a putative target gene for miR-21 during salamander limb regeneration. We cloned the full length 3′UTR of Amex-Jag1, and our in vitro assays demonstrated that its single miR-21 target recognition site is functional and essential for the response of the Jagged1 gene to miR-21 levels. Our findings pave the road for advanced in vivo functional assays aimed to clarify how microRNAs such as miR-21, often linked to pathogenic cell growth, might be modulating the redeployment of developmental genes such as Jagged1 during regenerative processes. PMID:23028429

  10. Microarray analysis of microRNA expression during axolotl limb regeneration.

    Directory of Open Access Journals (Sweden)

    Edna C Holman

    Full Text Available Among vertebrates, salamanders stand out for their remarkable capacity to quickly regrow a myriad of tissues and organs after injury or amputation. The limb regeneration process in axolotls (Ambystoma mexicanum has been well studied for decades at the cell-tissue level. While several developmental genes are known to be reactivated during this epimorphic process, less is known about the role of microRNAs in urodele amphibian limb regeneration. Given the compelling evidence that many microRNAs tightly regulate cell fate and morphogenetic processes through development and adulthood by modulating the expression (or re-expression of developmental genes, we investigated the possibility that microRNA levels change during limb regeneration. Using two different microarray platforms to compare the axolotl microRNA expression between mid-bud limb regenerating blastemas and non-regenerating stump tissues, we found that miR-21 was overexpressed in mid-bud blastemas compared to stump tissue. Mature A. mexicanum ("Amex" miR-21 was detected in axolotl RNA by Northern blot and differential expression of Amex-miR-21 in blastema versus stump was confirmed by quantitative RT-PCR. We identified the Amex Jagged1 as a putative target gene for miR-21 during salamander limb regeneration. We cloned the full length 3'UTR of Amex-Jag1, and our in vitro assays demonstrated that its single miR-21 target recognition site is functional and essential for the response of the Jagged1 gene to miR-21 levels. Our findings pave the road for advanced in vivo functional assays aimed to clarify how microRNAs such as miR-21, often linked to pathogenic cell growth, might be modulating the redeployment of developmental genes such as Jagged1 during regenerative processes.

  11. Analysis of embryonic development in the unsequenced axolotl: waves of transcriptomic upheaval and stability

    Science.gov (United States)

    Jiang, Peng; Nelson, Jeffrey D.; Leng, Ning; Collins, Michael; Swanson, Scott; Dewey, Colin N.; Thomson, James A.; Stewart, Ron

    2016-01-01

    The axolotl (Ambystoma mexicanum) has long been the subject of biological research, primarily owing to its outstanding regenerative capabilities. However, the gene expression programs governing its embryonic development are particularly underexplored, especially when compared to other amphibian model species. Therefore, we performed whole transcriptome polyA+ RNA sequencing experiments on 17 stages of embryonic development. As the axolotl genome is unsequenced and its gene annotation is incomplete, we built de novo transcriptome assemblies for each stage and garnered functional annotation by comparing expressed contigs with known genes in other organisms. In evaluating the number of differentially expressed genes over time, we identify three waves of substantial transcriptome upheaval each followed by a period of relative transcriptome stability. The first wave of upheaval is between the one and two cell stage. We show that the number of differentially expressed genes per unit time is higher between the one and two cell stage than it is across the mid-blastula transition (MBT), the period of zygotic genome activation. We use total RNA sequencing to demonstrate that the vast majority of genes with increasing polyA+ signal between the one and two cell stage result from polyadenylation rather than de novo transcription. The first stable phase begins after the two cell stage and continues until the mid-blastula transition, corresponding with the pre-MBT phase of transcriptional quiescence in amphibian development. Following this is a peak of differential gene expression corresponding with the activation of the zygotic genome and a phase of transcriptomic stability from stages 9 to 11. We observe a third wave of transcriptomic change between stages 11 and 14, followed by a final stable period. The last two stable phases have not been documented in amphibians previously and correspond to times of major morphogenic change in the axolotl embryo: gastrulation and

  12. Cranial muscle development in the model organism ambystoma mexicanum: implications for tetrapod and vertebrate comparative and evolutionary morphology and notes on ontogeny and phylogeny.

    Science.gov (United States)

    Ziermann, Janine M; Diogo, Rui

    2013-07-01

    There is still confusion about the homology of several cranial muscles in salamanders with those of other vertebrates. This is true, in part, because of the fact that many muscles present in early ontogeny of amphibians disappear during development and specifically during metamorphosis. Resolving this confusion is important for the understanding of the comparative and evolutionary morphology of vertebrates and tetrapods because amphibians are the phylogenetically most plesiomorphic tetrapods, concerning for example their myology, and include two often used model organisms, Xenopus laevis (anuran) and Ambystoma mexicanum (urodele). Here we provide the first detailed report of the cranial muscle development in axolotl from early ontogenetic stages to the adult stage. We describe different and complementary types of general muscle morphogenetic gradients in the head: from anterior to posterior, from lateral to medial, and from origin to insertion. Furthermore, even during the development of neotenic salamanders such as axolotls, various larval muscles become indistinct, contradicting the commonly accepted view that during ontogeny the tendency is mostly toward the differentiation of muscles. We provide an updated comparison between these muscles and the muscles of other vertebrates, a discussion of the homologies and evolution, and show that the order in which the muscles appear during axolotl ontogeny is in general similar to their appearance in phylogeny (e.g. differentiation of adductor mandibulae muscles from one anlage to four muscles), with only a few remarkable exceptions, as for example the dilatator laryngis that appears evolutionary later but in the development before the intermandibularis. Copyright © 2013 Wiley Periodicals, Inc.

  13. Positional information is reprogrammed in blastema cells of the regenerating limb of the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    McCusker, Catherine D; Gardiner, David M

    2013-01-01

    The regenerating region of an amputated salamander limb, known as the blastema, has the amazing capacity to replace exactly the missing structures. By grafting cells from different stages and regions of blastemas induced to form on donor animals expressing Green Fluorescent Protein (GFP), to non-GFP host animals, we have determined that the cells from early stage blastemas, as well as cells at the tip of late stage blastemas are developmentally labile such that their positional identity is reprogrammed by interactions with more proximal cells with stable positional information. In contrast, cells from the adjacent, more proximal stump tissues as well as the basal region of late bud blastemas are positionally stable, and thus form ectopic limb structures when grafted. Finally, we have found that a nerve is required to maintain the blastema cells in a positionally labile state, thus indicating a role for reprogramming cues in the blastema microenvironment.

  14. Positional information is reprogrammed in blastema cells of the regenerating limb of the axolotl (Ambystoma mexicanum.

    Directory of Open Access Journals (Sweden)

    Catherine D McCusker

    Full Text Available The regenerating region of an amputated salamander limb, known as the blastema, has the amazing capacity to replace exactly the missing structures. By grafting cells from different stages and regions of blastemas induced to form on donor animals expressing Green Fluorescent Protein (GFP, to non-GFP host animals, we have determined that the cells from early stage blastemas, as well as cells at the tip of late stage blastemas are developmentally labile such that their positional identity is reprogrammed by interactions with more proximal cells with stable positional information. In contrast, cells from the adjacent, more proximal stump tissues as well as the basal region of late bud blastemas are positionally stable, and thus form ectopic limb structures when grafted. Finally, we have found that a nerve is required to maintain the blastema cells in a positionally labile state, thus indicating a role for reprogramming cues in the blastema microenvironment.

  15. Regulation of proximal-distal intercalation during limb regeneration in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, Akira; Cummings, Gillian M C; Bryant, Susan V; Gardiner, David M

    2010-12-01

    Intercalation is the process whereby cells located at the boundary of a wound interact to stimulate proliferation and the restoration of the structures between the boundaries that were lost during wounding. Thus, intercalation is widely considered to be the mechanism of regeneration. When a salamander limb is amputated, the entire cascade of regeneration events is activated, and the missing limb segments and their boundaries (joints) as well as the structures within each segment are regenerated. Therefore, in an amputated limb it is not possible to distinguish between intersegmental regeneration (formation of new segments/joints) and intrasegmental regeneration (formation of structures within a given segment), and it is not possible to study the differential regulation of these two processes. We have used two models for regeneration that allow us to study these two processes independently, and report that inter- and intrasegmental regeneration are different processes regulated by different signaling pathways. New limb segments/joints can be regenerated from cells that dedifferentiate to form blastema cells in response to signaling that is mediated in part by fibroblast growth factor. © 2010 The Authors. Journal compilation © 2010 Japanese Society of Developmental Biologists.

  16. Microarray analysis identifies keratin loci as sensitive biomarkers for thyroid hormone disruption in the salamander Ambystoma mexicanum.

    Science.gov (United States)

    Page, Robert B; Monaghan, James R; Samuels, Amy K; Smith, Jeramiah J; Beachy, Christopher K; Voss, S Randal

    2007-02-01

    Ambystomatid salamanders offer several advantages for endocrine disruption research, including genomic and bioinformatics resources, an accessible laboratory model (Ambystoma mexicanum), and natural lineages that are broadly distributed among North American habitats. We used microarray analysis to measure the relative abundance of transcripts isolated from A. mexicanum epidermis (skin) after exogenous application of thyroid hormone (TH). Only one gene had a >2-fold change in transcript abundance after 2 days of TH treatment. However, hundreds of genes showed significantly different transcript levels at days 12 and 28 in comparison to day 0. A list of 123 TH-responsive genes was identified using statistical, BLAST, and fold level criteria. Cluster analysis identified two groups of genes with similar transcription patterns: up-regulated versus down-regulated. Most notably, several keratins exhibited dramatic (1000 fold) increases or decreases in transcript abundance. Keratin gene expression changes coincided with morphological remodeling of epithelial tissues. This suggests that keratin loci can be developed as sensitive biomarkers to assay temporal disruptions of larval-to-adult gene expression programs. Our study has identified the first collection of loci that are regulated during TH-induced metamorphosis in a salamander, thus setting the stage for future investigations of TH disruption in the Mexican axolotl and other salamanders of the genus Ambystoma.

  17. Tooth development in Ambystoma mexicanum: phosphatase activities, calcium accumulation and cell proliferation in the tooth-forming tissues.

    Science.gov (United States)

    Wistuba, Joachim; Ehmcke, Jens; Clemen, Günter

    2003-06-01

    Prerequisites of tooth formation, cell proliferation in the tooth-forming tissues, calcium accumulation and the enzymatic activities of alkaline (ALP) and acid phosphatases (ACP) were investigated by immunohistochemical and histochemical methods in various developmental stages of the Mexican Axolotl, Ambystoma mexicanum. During the growth of replacement teeth, the tooth-forming tissues continually recruit cells from the surrounding regions. The basal layer of the oral epithelium, the dental lamina and sometimes even the outer enamel epithelium provide cells for the differentiated inner enamel epithelium, in which the active ameloblasts are localized. The differentiating odontoblasts are derived from proliferating cells situated basally to the replacement teeth in the mesenchymal tissue. When differentiation has started and the cells have become functional, proliferative activity can no longer be observed. Calcium is accumulated close to the site of mineralization in the inner enamel epithelium and in the odontoblasts as it is in mammals, elasmobranchii and teleostei. The activities of ACP and ALP related to the mineralization of the replacement teeth are separated spatially and not sequentially as they are in mammals. However, the results indicate a similar function of these enzymatic components in relation to tooth formation and maturation of mineral deposition. Most of the substantial processes related to tooth formation reported from other vertebrates occur in a manner similar to that in Ambystoma mexicanum, but there also seem to be basic mechanisms present that are realised in a unique way in this urodele.

  18. A Baecklund transformation between two integrable discrete hungry systems

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Akiko, E-mail: j1409704@ed.kagu.tus.ac.j [Department of Mathematical Information Science, Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Yamamoto, Yusaku [Graduate School of System Informatics, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501 (Japan); Iwasaki, Masashi [Department of Informatics and Environmental Science, Kyoto Prefectural University, 1-5, Nakaragi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522 (Japan); Ishiwata, Emiko [Department of Mathematical Information Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Nakamura, Yoshimasa [Graduate School of Informatics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2011-01-17

    The discrete hungry Toda (dhToda) equation and the discrete hungry Lotka-Volterra (dhLV) system are known as integrable discrete hungry systems. In this Letter, through finding the LR transformations associated with the dhToda equation and the dhLV system, we present a Baecklund transformation between these integrable systems.

  19. A Baecklund transformation between two integrable discrete hungry systems

    International Nuclear Information System (INIS)

    Fukuda, Akiko; Yamamoto, Yusaku; Iwasaki, Masashi; Ishiwata, Emiko; Nakamura, Yoshimasa

    2011-01-01

    The discrete hungry Toda (dhToda) equation and the discrete hungry Lotka-Volterra (dhLV) system are known as integrable discrete hungry systems. In this Letter, through finding the LR transformations associated with the dhToda equation and the dhLV system, we present a Baecklund transformation between these integrable systems.

  20. A novel protein involved in heart development in Ambystoma mexicanum is localized in endoplasmic reticulum.

    Science.gov (United States)

    Jia, P; Zhang, C; Huang, X P; Poda, M; Akbas, F; Lemanski, S L; Erginel-Unaltuna, N; Lemanski, L F

    2008-11-01

    The discovery of the naturally occurring cardiac non-function (c) animal strain in Ambystoma mexicanum (axolotl) provides a valuable animal model to study cardiomyocyte differentiation. In homozygous mutant animals (c/c), rhythmic contractions of the embryonic heart are absent due to a lack of organized myofibrils. We have previously cloned a partial sequence of a peptide cDNA (N1) from an anterior-endoderm-conditioned-medium RNA library that had been shown to be able to rescue the mutant phenotype. In the current studies we have fully cloned the N1 full length cDNA sequence from the library. N1 protein has been detected in both adult heart and skeletal muscle but not in any other adult tissues. GFP-tagged expression of the N1 protein has revealed localization of the N1 protein in the endoplasmic reticulum (ER). Results from in situ hybridization experiments have confirmed the dramatic decrease of expression of N1 mRNA in mutant (c/c) embryos indicating that the N1 gene is involved in heart development.

  1. Activation of germline-specific genes is required for limb regeneration in the Mexican axolotl

    Science.gov (United States)

    Zhu, Wei; Pao, Gerald M; Satoh, Akira; Cummings, Gillian; Monaghan, James R; Harkins, Timothy T; Bryant, Susan V; Voss, S Randal; Gardiner, David M; Hunter, Tony

    2013-01-01

    The capacity for tissue and organ regeneration in humans is dwarfed by comparison to that of salamanders. Emerging evidence suggests that mechanisms learned from the early phase of salamander limb regeneration – wound healing, cellular dedifferentiation and blastemal formation – will reveal therapeutic approaches for tissue regeneration in humans. Here we describe a unique transcriptional fingerprint of regenerating limb tissue in the Mexican axolotl (Ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells to a germline-like state. Two genes that are required for self-renewal of germ cells in mice and flies, Piwi-like 1 (PL1) and Piwi-like 2 (PL2), are expressed in limb blastemal cells, the basal layer keratinocytes and the thickened apical epithelial cap in the wound epidermis in the regenerating limb. Depletion of PL1 and PL2 by morpholino oligonucleotides decreased cell proliferation and increased cell death in the blastema leading to a significant retardation of regeneration. Examination of key molecules that are known to be required for limb development or regeneration further revealed that FGF8 is transcriptionally downregulated in the presence of the morpholino oligos, indicating PL1 and PL2 might participate in FGF signaling during limb regeneration. Given the requirement for FGF signaling in limb development and regeneration, the results suggest that PL1 and PL2 function to establish a unique germline-like state that is associated with successful regeneration. PMID:22841627

  2. Limb Regeneration in Axolotl: Is It Superhealing?

    Directory of Open Access Journals (Sweden)

    Stéphane Roy

    2006-01-01

    Full Text Available The ability of axolotls to regenerate their limbs is almost legendary. In fact, urodeles such as the axolotl are the only vertebrates that can regenerate multiple structures like their limbs, jaws, tail, spinal cord, and skin (the list goes on throughout their lives. It is therefore surprising to realize, although we have known of their regenerative potential for over 200 years, how little we understand the mechanisms behind this achievement of adult tissue morphogenesis. Many observations can be drawn between regeneration and other disciplines such as development and wound healing. In this review, we present new developments in functional analysis that will help to address the role of specific genes during the process of regeneration. We also present an analysis of the resemblance between wound healing and regeneration, and discuss whether axolotls are superhealers. A better understanding of these animals' regenerative capacity could lead to major benefits by providing regenerative medicine with directions on how to develop therapeutic approaches leading to regeneration in humans.

  3. Neuropeptide Y enhances olfactory mucosa responses to odorant in hungry rats.

    Science.gov (United States)

    Negroni, Julia; Meunier, Nicolas; Monnerie, Régine; Salesse, Roland; Baly, Christine; Caillol, Monique; Congar, Patrice

    2012-01-01

    Neuropeptide Y (NPY) plays an important role in regulating appetite and hunger in vertebrates. In the hypothalamus, NPY stimulates food intake under the control of the nutritional status. Previous studies have shown the presence of NPY and receptors in rodent olfactory system, and suggested a neuroproliferative role. Interestingly, NPY was also shown to directly modulate olfactory responses evoked by a food-related odorant in hungry axolotls. We have recently demonstrated that another nutritional cue, insulin, modulates the odorant responses of the rat olfactory mucosa (OM). Therefore, the aim of the present study was to investigate the potential effect of NPY on rat OM responses to odorants, in relation to the animal's nutritional state. We measured the potential NPY modulation of OM responses to odorant, using electro-olfactogram (EOG) recordings, in fed and fasted adult rats. NPY application significantly and transiently increased EOG amplitudes in fasted but not in fed rats. The effects of specific NPY-receptor agonists were similarly quantified, showing that NPY operated mainly through Y1 receptors. These receptors appeared as heterogeneously expressed by olfactory neurons in the OM, and western blot analysis showed that they were overexpressed in fasted rats. These data provide the first evidence that NPY modulates the initial events of odorant detection in the rat OM. Because this modulation depends on the nutritional status of the animal, and is ascribed to NPY, the most potent orexigenic peptide in the central nervous system, it evidences a strong supplementary physiological link between olfaction and nutritional processes.

  4. The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities

    Science.gov (United States)

    Chen, Xiaoping; Song, Fengyu; Jhamb, Deepali; Li, Jiliang; Bottino, Marco C.; Palakal, Mathew J.; Stocum, David L.

    2015-01-01

    We tested the ability of the axolotl (Ambystoma mexicanum) fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS) scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process. PMID:26098852

  5. The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities.

    Directory of Open Access Journals (Sweden)

    Xiaoping Chen

    Full Text Available We tested the ability of the axolotl (Ambystoma mexicanum fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process.

  6. Initial characterization of the large genome of the salamander Ambystoma mexicanum using shotgun and laser capture chromosome sequencing.

    Science.gov (United States)

    Keinath, Melissa C; Timoshevskiy, Vladimir A; Timoshevskaya, Nataliya Y; Tsonis, Panagiotis A; Voss, S Randal; Smith, Jeramiah J

    2015-11-10

    Vertebrates exhibit substantial diversity in genome size, and some of the largest genomes exist in species that uniquely inform diverse areas of basic and biomedical research. For example, the salamander Ambystoma mexicanum (the Mexican axolotl) is a model organism for studies of regeneration, development and genome evolution, yet its genome is ~10× larger than the human genome. As part of a hierarchical approach toward improving genome resources for the species, we generated 600 Gb of shotgun sequence data and developed methods for sequencing individual laser-captured chromosomes. Based on these data, we estimate that the A. mexicanum genome is ~32 Gb. Notably, as much as 19 Gb of the A. mexicanum genome can potentially be considered single copy, which presumably reflects the evolutionary diversification of mobile elements that accumulated during an ancient episode of genome expansion. Chromosome-targeted sequencing permitted the development of assemblies within the constraints of modern computational platforms, allowed us to place 2062 genes on the two smallest A. mexicanum chromosomes and resolves key events in the history of vertebrate genome evolution. Our analyses show that the capture and sequencing of individual chromosomes is likely to provide valuable information for the systematic sequencing, assembly and scaffolding of large genomes.

  7. Positive in vitro wound healing effects of functional inclusion bodies of a lipoxygenase from the Mexican axolotl.

    Science.gov (United States)

    Stamm, Anne; Strauß, Sarah; Vogt, Peter; Scheper, Thomas; Pepelanova, Iliyana

    2018-04-07

    AmbLOXe is a lipoxygenase, which is up-regulated during limb-redevelopment in the Mexican axolotl, Ambystoma mexicanum, an animal with remarkable regeneration capacity. Previous studies have shown that mammalian cells transformed with the gene of this epidermal lipoxygenase display faster migration and wound closure rate during in vitro wound healing experiments. In this study, the gene of AmbLOXe was codon-optimized for expression in Escherichia coli and was produced in the insoluble fraction as protein aggregates. These inclusion bodies or nanopills were shown to be reservoirs containing functional protein during in vitro wound healing assays. For this purpose, functional inclusion bodies were used to coat cell culture surfaces prior cell seeding or were added directly to the medium after cells reached confluence. In both scenarios, AmbLOXe inclusion bodies led to faster migration rate and wound closure, in comparison to controls containing either no AmbLOXe or GFP inclusion bodies. Our results demonstrate that AmbLOXe inclusion bodies are functional and may serve as stable reservoirs of this enzyme. Nevertheless, further studies with soluble enzyme are also necessary in order to start elucidating the exact molecular substrates of AmbLOXe and the biochemical pathways involved in the wound healing effect.

  8. Lens regeneration in axolotl: new evidence of developmental plasticity

    Directory of Open Access Journals (Sweden)

    Suetsugu-Maki Rinako

    2012-12-01

    Full Text Available Abstract Background Among vertebrates lens regeneration is most pronounced in newts, which have the ability to regenerate the entire lens throughout their lives. Regeneration occurs from the dorsal iris by transdifferentiation of the pigment epithelial cells. Interestingly, the ventral iris never contributes to regeneration. Frogs have limited lens regeneration capacity elicited from the cornea during pre-metamorphic stages. The axolotl is another salamander which, like the newt, regenerates its limbs or its tail with the spinal cord, but up until now all reports have shown that it does not regenerate the lens. Results Here we present a detailed analysis during different stages of axolotl development, and we show that despite previous beliefs the axolotl does regenerate the lens, however, only during a limited time after hatching. We have found that starting at stage 44 (forelimb bud stage lens regeneration is possible for nearly two weeks. Regeneration occurs from the iris but, in contrast to the newt, regeneration can be elicited from either the dorsal or the ventral iris and, occasionally, even from both in the same eye. Similar studies in the zebra fish concluded that lens regeneration is not possible. Conclusions Regeneration of the lens is possible in the axolotl, but differs from both frogs and newts. Thus the axolotl iris provides a novel and more plastic strategy for lens regeneration.

  9. Hungry Cities Initiative: Informality, Inclusive Growth, and Food ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Hungry Cities Initiative: Informality, Inclusive Growth, and Food Security in ... Within this context, the urban food economy is an important laboratory for ... The International Partnerships for Sustainable Societies program is funding this project.

  10. Nerve signaling regulates basal keratinocyte proliferation in the blastema apical epithelial cap in the axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Satoh, Akira; Bryant, Susan V; Gardiner, David M

    2012-06-15

    The ability of adult vertebrates to repair tissue damage is widespread and impressive; however, the ability to regenerate structurally complex organs such as the limb is limited largely to the salamanders. The fact that most of the tissues of the limb can regenerate has led investigators to question and identify the barriers to organ regeneration. From studies in the salamander, it is known that one of the earliest steps required for successful regeneration involves signaling between nerves and the wound epithelium/apical epithelial cap (AEC). In this study we confirm an earlier report that the keratinocytes of the AEC acquire their function coincident with exiting the cell cycle. We have discovered that this unique, coordinated behavior is regulated by nerve signaling and is associated with the presence of gap junctions between the basal keratinocytes of the AEC. Disruption of nerve signaling results in a loss of gap junction protein, the reentry of the cells into the cell cycle, and regenerative failure. Finally, coordinated exit from the cell cycle appears to be a conserved behavior of populations of cells that function as signaling centers during both development and regeneration. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Gain-of-function assays in the axolotl (Ambystoma mexicanum) to identify signaling pathways that induce and regulate limb regeneration.

    Science.gov (United States)

    Lee, Jangwoo; Aguilar, Cristian; Gardiner, David

    2013-01-01

    The adult salamander has been studied as a model for regeneration of complex tissues for many decades. Only recently with the development of gain-of-function assays for regeneration, has it been possible to screen for and assay the function of the multitude of signaling factors that have been identified in studies of embryonic development and tumorigenesis. Given the conservation of function of these regulatory pathways controlling growth and pattern formation, it is now possible to use the functional assays in the salamander to test the ability of endogenous as well as small-molecule signaling factors to induce a regenerative response.

  12. Novel axolotl cardiac function analysis method using magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Pedro Gomes Sanches

    Full Text Available The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a non-invasive technique to image heart function of axolotls. Three axolotls were imaged with magnetic resonance imaging using a retrospectively gated Fast Low Angle Shot cine sequence. Within one scanning session the axolotl heart was imaged three times in all planes, consecutively. Heart rate, ejection fraction, stroke volume and cardiac output were calculated using three techniques: (1 combined long-axis, (2 short-axis series, and (3 ultrasound (control for heart rate only. All values are presented as mean ± standard deviation. Heart rate (beats per minute among different animals was 32.2±6.0 (long axis, 30.4±5.5 (short axis and 32.7±4.9 (ultrasound and statistically similar regardless of the imaging method (p > 0.05. Ejection fraction (% was 59.6±10.8 (long axis and 48.1±11.3 (short axis and it differed significantly (p = 0.019. Stroke volume (μl/beat was 133.7±33.7 (long axis and 93.2±31.2 (short axis, also differed significantly (p = 0.015. Calculations were consistent among the animals and over three repeated measurements. The heart rate varied depending on depth of anaesthesia. We described a new method for defining and imaging the anatomical planes of the axolotl heart and propose one of our techniques (long axis analysis may prove useful in defining cardiac function in regenerating axolotl hearts.

  13. Hungry Horse mitigation: Aquatic modeling of the selective withdrawal system -- Hungry Horse Dam, Montana

    International Nuclear Information System (INIS)

    Marotz, B.L.; Althen, C.; Gustafson, D.

    1994-04-01

    Hungry Horse Dam presently releases frigid water from the bottom of the reservoir all year long. Cold water effects insect production and fish growth downstream. Rapid temperature changes of up to 8.3 C (14 F) have been measured in the Flathead River downstream of the South Fork confluence, controlled by dam discharges. Thermal effects from Hungry Horse Dam are detectable for over 64 Km downstream to Flathead Lake. The installation of a selective withdrawal structure on each of the dam's discharge penstocks was determined to be the most cost-effective means to provide constant, permanent temperature control without impacting power production and flexibility in dam operation. The thermal model presented herein revealed that fish growth potential in the river would increase two to five times through selective withdrawal, temperature control. Temperature control is possible over the entire range of turbine discharge capacity, with very little effect on power production. Findings indicate that angling would improve through higher catch rates and larger fish. Temperature control will solve the most serious impact to river health. However, flow fluctuations will continue to effect insect production and usable fishery habitat in the Flathead River. A natural thermal regime combined with moderated flow fluctuation would further enhance riverine food production, trout growth and recreation potential

  14. Early regulation of axolotl limb regeneration.

    Science.gov (United States)

    Makanae, Aki; Satoh, Akira

    2012-10-01

    Amphibian limb regeneration has been studied for a long time. In amphibian limb regeneration, an undifferentiated blastema is formed around the region damaged by amputation. The induction process of blastema formation has remained largely unknown because it is difficult to study the induction of limb regeneration. The recently developed accessory limb model (ALM) allows the investigation of limb induction and reveals early events of amphibian limb regeneration. The interaction between nerves and wound epidermis/epithelium is an important aspect of limb regeneration. During early limb regeneration, neurotrophic factors act on wound epithelium, leading to development of a functional epidermis/epithelium called the apical epithelial cap (AEC). AEC and nerves create a specific environment that inhibits wound healing and induces regeneration through blastema formation. It is suggested that FGF-signaling and MMP activities participate in creating a regenerative environment. To understand why urodele amphibians can create such a regenerative environment and humans cannot, it is necessary to identify the similarities and differences between regenerative and nonregenerative animals. Here we focus on ALM to consider limb regeneration from a new perspective and we also reported that focal adhesion kinase (FAK)-Src signaling controlled fibroblasts migration in axolotl limb regeneration. Copyright © 2012 Wiley Periodicals, Inc.

  15. Continuous growth of the motor system in the axolotl

    International Nuclear Information System (INIS)

    Holder, N.; Clarke, J.D.; Stephens, N.; Wilson, S.W.; Orsi, C.; Bloomer, T.; Tonge, D.A.

    1991-01-01

    During growth of the axolotl, motor neurons, and muscle fibres are added to the motor system. By double labelling neurons with tritiated thymidine and retrogradely transported HRP, we show that some motor neurons are born at postembryonic stages. Further analysis of motor neurons with the aid of HRP reveals this population of newly born cells relatively frequently in small (5-7 cm long) axolotls, but only rarely in large (7-13 cm long) axolotls. Evidence is presented that suggests that these immature cells are in the process of migrating from close to the ependyma out to the ventral horn. HRP transport also reveals growth cones of advancing axons within spinal nerves in animals up to 6 cm in length. Cell counts by light and electron microscopic methods show that muscle fibres are generated throughout larval life in the iliotibialis, a typical limb muscle. This analysis provides data consistent with the notion that new muscle fibres are added from a localised growth zone situated at the superficial edge of the muscle. These results are discussed in terms of the correlation between continuous growth of the motor system and the ability of the axolotl to functionally repair lesions to the peripheral nervous system

  16. Novel axolotl cardiac function analysis method using magnetic resonance imaging

    NARCIS (Netherlands)

    Sanches, Pedro Gomes; Op 't Veld, Roel C.; de Graaf, Wolter; Strijkers, Gustav J.; Grüll, Holger

    2017-01-01

    The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a non-invasive technique to image heart function

  17. Novel axolotl cardiac function analysis method using magnetic resonance imaging

    NARCIS (Netherlands)

    Sanches, P.G.; Op ‘t Veld, R.C.; de Graaf, W.; Strijkers, G.J.; Grüll, H.

    2017-01-01

    The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a noninvasive technique to image heart function of

  18. Transcriptome dynamics along axolotl regenerative development are consistent with an extensive reduction in gene expression heterogeneity in dedifferentiated cells

    Directory of Open Access Journals (Sweden)

    Carlos Díaz-Castillo

    2017-11-01

    Full Text Available Although in recent years the study of gene expression variation in the absence of genetic or environmental cues or gene expression heterogeneity has intensified considerably, many basic and applied biological fields still remain unaware of how useful the study of gene expression heterogeneity patterns might be for the characterization of biological systems and/or processes. Largely based on the modulator effect chromatin compaction has for gene expression heterogeneity and the extensive changes in chromatin compaction known to occur for specialized cells that are naturally or artificially induced to revert to less specialized states or dedifferentiate, I recently hypothesized that processes that concur with cell dedifferentiation would show an extensive reduction in gene expression heterogeneity. The confirmation of the existence of such trend could be of wide interest because of the biomedical and biotechnological relevance of cell dedifferentiation-based processes, i.e., regenerative development, cancer, human induced pluripotent stem cells, or plant somatic embryogenesis. Here, I report the first empirical evidence consistent with the existence of an extensive reduction in gene expression heterogeneity for processes that concur with cell dedifferentiation by analyzing transcriptome dynamics along forearm regenerative development in Ambystoma mexicanum or axolotl. Also, I briefly discuss on the utility of the study of gene expression heterogeneity dynamics might have for the characterization of cell dedifferentiation-based processes, and the engineering of tools that afforded better monitoring and modulating such processes. Finally, I reflect on how a transitional reduction in gene expression heterogeneity for dedifferentiated cells can promote a long-term increase in phenotypic heterogeneity following cell dedifferentiation with potential adverse effects for biomedical and biotechnological applications.

  19. Functional characterization of the vertebrate primary ureter: Structure and ion transport mechanisms of the pronephric duct in axolotl larvae (Amphibia

    Directory of Open Access Journals (Sweden)

    Prehn Lea R

    2010-05-01

    Full Text Available Abstract Background Three kidney systems appear during vertebrate development: the pronephroi, mesonephroi and metanephroi. The pronephric duct is the first or primary ureter of these kidney systems. Its role as a key player in the induction of nephrogenic mesenchyme is well established. Here we investigate whether the duct is involved in urine modification using larvae of the freshwater amphibian Ambystoma mexicanum (axolotl as model. Results We investigated structural as well as physiological properties of the pronephric duct. The key elements of our methodology were: using histology, light and transmission electron microscopy as well as confocal laser scanning microscopy on fixed tissue and applying the microperfusion technique on isolated pronephric ducts in combination with single cell microelectrode impalements. Our data show that the fully differentiated pronephric duct is composed of a single layered epithelium consisting of one cell type comparable to the principal cell of the renal collecting duct system. The cells are characterized by a prominent basolateral labyrinth and a relatively smooth apical surface with one central cilium. Cellular impalements demonstrate the presence of apical Na+ and K+ conductances, as well as a large K+ conductance in the basolateral cell membrane. Immunolabeling experiments indicate heavy expression of Na+/K+-ATPase in the basolateral labyrinth. Conclusions We propose that the pronephric duct is important for the subsequent modification of urine produced by the pronephros. Our results indicate that it reabsorbs sodium and secretes potassium via channels present in the apical cell membrane with the driving force for ion movement provided by the Na+/K+ pump. This is to our knowledge the first characterization of the pronephric duct, the precursor of the collecting duct system, which provides a model of cell structure and basic mechanisms for ion transport. Such information may be important in understanding

  20. Transcriptome dynamics along axolotl regenerative development are consistent with an extensive reduction in gene expression heterogeneity in dedifferentiated cells

    Science.gov (United States)

    2017-01-01

    Although in recent years the study of gene expression variation in the absence of genetic or environmental cues or gene expression heterogeneity has intensified considerably, many basic and applied biological fields still remain unaware of how useful the study of gene expression heterogeneity patterns might be for the characterization of biological systems and/or processes. Largely based on the modulator effect chromatin compaction has for gene expression heterogeneity and the extensive changes in chromatin compaction known to occur for specialized cells that are naturally or artificially induced to revert to less specialized states or dedifferentiate, I recently hypothesized that processes that concur with cell dedifferentiation would show an extensive reduction in gene expression heterogeneity. The confirmation of the existence of such trend could be of wide interest because of the biomedical and biotechnological relevance of cell dedifferentiation-based processes, i.e., regenerative development, cancer, human induced pluripotent stem cells, or plant somatic embryogenesis. Here, I report the first empirical evidence consistent with the existence of an extensive reduction in gene expression heterogeneity for processes that concur with cell dedifferentiation by analyzing transcriptome dynamics along forearm regenerative development in Ambystoma mexicanum or axolotl. Also, I briefly discuss on the utility of the study of gene expression heterogeneity dynamics might have for the characterization of cell dedifferentiation-based processes, and the engineering of tools that afforded better monitoring and modulating such processes. Finally, I reflect on how a transitional reduction in gene expression heterogeneity for dedifferentiated cells can promote a long-term increase in phenotypic heterogeneity following cell dedifferentiation with potential adverse effects for biomedical and biotechnological applications. PMID:29134148

  1. Nutritive and replacement value of hungry rice ''Acha'' ( Digitaria ...

    African Journals Online (AJOL)

    The hungry rice grains (HG) were determined for nutrients and anti nutrients and evaluated for growth performance. Five dietary diets were formulated with AG replacing maize at 0, 25, 50, 75 and 100 %. A total of 150 7days-old broiler chicks (Abor-Acre) were randomly allotted to five treatments of 30 birds each, replicated ...

  2. Benefits of a hungry mind: When hungry, exposure to food facilitates proactive interference resolution.

    Science.gov (United States)

    Maran, Thomas; Sachse, Pierre; Martini, Markus; Furtner, Marco

    2017-01-01

    Hunger is an everyday motivational state, which biases cognition to detect food. Although evidence exists on how hunger affects basic attentional and mnemonic processes, less is known about how motivational drive for food modulates higher cognition. We aimed to investigate the effects of food deprivation on proactive interference resolution, in the presence and absence of food. Normal-weight participants performed a recency probes paradigm providing an experimental block with food and object stimuli as well as a control block with object stimuli only, in a fasted and a sated state. Results showed that the interaction of shifts in nutritional state with the perception of food cues evoked an altered resolution of proactive interference. Satiety led to impaired performance, whereas a hungry state resulted in strengthened resistance to proactive interference and lying in between, the control block presenting neutral objects remained unaffected by nutritional state manipulation. Additionally, a further increase in proactive interference resolution occurred when the conflicting probe depicted food compared to non-food objects. We conclude that when exposed to food, hunger initiates biased competition of active memory representations in favor of prioritized source information at cost of familiar, but irrelevant information. The implications of these findings are discussed in terms of an arousal-biased competition in working memory. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Axolotl cells and tissues enhances cutaneous wound healing in mice

    OpenAIRE

    DEMIRCAN, Turan; KESKIN, Ilknur; GUNAL, Yalcin; ILHAN, Ayse Elif; KOLBASI, Bircan; OZTURK, Gurkan

    2017-01-01

    Adult mammalian skin wound repair is defective due to loss of the regulation in balancing the complete epithelial regeneration and excessive connective tissue production, and this repair process commonly results in scar tissue formation. However, unlike mammals, adult salamanders repair the wounds by regeneration compared to scarring. To elucidate the healing capability of a salamander, Axolotl, in a different species, here we addressed this question by treating the wounds in mice with Axolot...

  4. Diffusion tensor tractography reveals muscle reconnection during axolotl limb regeneration.

    Directory of Open Access Journals (Sweden)

    Cheng-Han Wu

    Full Text Available Axolotls have amazing ability to regenerate their lost limbs. Our previous works showed that after amputation the remnant muscle ends remained at their original location whilst sending satellite cells into the regenerating parts to develop into early muscle fibers in the late differentiation stage. The parental and the newly formed muscle fibers were not connected until very late stage. The present study used non-invasive diffusion tensor imaging (DTI to monitor weekly axolotl upper arm muscles after amputation of their upper arms. DTI tractography showed that the regenerating muscle fibers became visible at 9-wpa (weeks post amputation, but a gap was observed between the regenerating and parental muscles. The gap was filled at 10-wpa, indicating reconnection of the fibers of both muscles. This was confirmed by histology. The DTI results indicate that 23% of the muscle fibers were reconnected at 10-wpa. In conclusion, DTI can be used to visualize axolotls' skeletal muscles and the results of muscle reconnection were in accordance with our previous findings. This non-invasive technique will allow researchers to identify the timeframe in which muscle fiber reconnection takes place and thus enable the study of the mechanisms underlying this reconnection.

  5. Gene order data from a model amphibian (Ambystoma: new perspectives on vertebrate genome structure and evolution

    Directory of Open Access Journals (Sweden)

    Voss S Randal

    2006-08-01

    Full Text Available Abstract Background Because amphibians arise from a branch of the vertebrate evolutionary tree that is juxtaposed between fishes and amniotes, they provide important comparative perspective for reconstructing character changes that have occurred during vertebrate evolution. Here, we report the first comparative study of vertebrate genome structure that includes a representative amphibian. We used 491 transcribed sequences from a salamander (Ambystoma genetic map and whole genome assemblies for human, mouse, rat, dog, chicken, zebrafish, and the freshwater pufferfish Tetraodon nigroviridis to compare gene orders and rearrangement rates. Results Ambystoma has experienced a rate of genome rearrangement that is substantially lower than mammalian species but similar to that of chicken and fish. Overall, we found greater conservation of genome structure between Ambystoma and tetrapod vertebrates, nevertheless, 57% of Ambystoma-fish orthologs are found in conserved syntenies of four or more genes. Comparisons between Ambystoma and amniotes reveal extensive conservation of segmental homology for 57% of the presumptive Ambystoma-amniote orthologs. Conclusion Our analyses suggest relatively constant interchromosomal rearrangement rates from the euteleost ancestor to the origin of mammals and illustrate the utility of amphibian mapping data in establishing ancestral amniote and tetrapod gene orders. Comparisons between Ambystoma and amniotes reveal some of the key events that have structured the human genome since diversification of the ancestral amniote lineage.

  6. Injection of an antibody against a p21 c-Ha-ras protein inhibits cleavage in axolotl eggs.

    OpenAIRE

    Baltus, E; Hanocq-Quertier, J; Hanocq, F; Brachet, J

    1988-01-01

    The presence of a ras protein was demonstrated in cleaving axolotl eggs by selective immunoprecipitation with a polyclonal antibody against a peptide encoded by the c-Ha-ras oncogene, cellular homolog of the v-Ha-ras oncogene of Harvey rat sarcoma virus. Injection of this antibody into axolotl oocytes subjected to progesterone treatment does not prevent meiotic maturation. Injection of the same antibody into a blastomere of axolotl eggs at the 2- or 4-cell stage causes cleavage arrest in the ...

  7. A Tissue-Mapped Axolotl De Novo Transcriptome Enables Identification of Limb Regeneration Factors

    Directory of Open Access Journals (Sweden)

    Donald M. Bryant

    2017-01-01

    Full Text Available Mammals have extremely limited regenerative capabilities; however, axolotls are profoundly regenerative and can replace entire limbs. The mechanisms underlying limb regeneration remain poorly understood, partly because the enormous and incompletely sequenced genomes of axolotls have hindered the study of genes facilitating regeneration. We assembled and annotated a de novo transcriptome using RNA-sequencing profiles for a broad spectrum of tissues that is estimated to have near-complete sequence information for 88% of axolotl genes. We devised expression analyses that identified the axolotl orthologs of cirbp and kazald1 as highly expressed and enriched in blastemas. Using morpholino anti-sense oligonucleotides, we find evidence that cirbp plays a cytoprotective role during limb regeneration whereas manipulation of kazald1 expression disrupts regeneration. Our transcriptome and annotation resources greatly complement previous transcriptomic studies and will be a valuable resource for future research in regenerative biology.

  8. Acid precipitation and reproductive success of Ambystoma salamanders

    Energy Technology Data Exchange (ETDEWEB)

    Pough, R H; Wilson, R E

    1976-01-01

    The two species of mole salamander that occur in the Ithaca, New York, region (Ambystoma maculatum and A. jeffersonianum) breed in temporary ponds that are formed by accumulation of melted snow and spring rains. Water in many of these pools during the breeding season is acid; pH values as low as 3.5 have been measured. In laboratory experiments A. maculatum tolerated pHs from 6 to 10 and had greatest hatching success at pH 7 to 9. Ambystoma Jeffersonianum tolerated pH 4 to 8 and was most successful at pH 5 to 6. Mortality rose abruptly beyond the tolerance limits. The pH optimum shifted upward with increasing temperature for A. jeffersonianum and downward for A. maculatum. Judging from our laboratory studies, the acidity measured in breeding ponds should cause mortality in A. maculatum and permit normal development in A. jeffersonianum. In a four-year study of a large acidic vernal pond, 938 adult A. maculatum produced 486 metamorphosed juveniles (0.52 juvenile/adult), while 686 adult A. jeffersonianum produced 2157 juveniles (3.14 juveniles/adult). Because the effects of acid precipitation on the salamanders' breeding ponds are cumulative from year to year, profound changes in the salamander populations can be anticipated.

  9. Acid precipitation and reproductive success of Ambystoma salamanders

    Energy Technology Data Exchange (ETDEWEB)

    Pough, F H; Wilson, R E

    1977-03-01

    The two species of mole salamander that occur in the Ithaca, New York, region (Ambystoma maculatum and A. jeffersonianum) breed in temporary ponds that are formed by accumulation of melted snow and spring rains. Water in many of these pools during the breeding season is acid; pH values as low as 3.5 have been measured. In laboratory experiments A. maculatum tolerated pHs from 6 to 10 and had greatest hatching success at pH 7 to 9. Ambystoma jeffersonianum tolerated pH 4 to 8 and was most successful at pH 5 to 6. Mortality rose abruptly beyond the tolerance limits. The pH optimum shifted upward with increasing temperature for A. jeffersonianum and downward for A. maculatum. Judging from our laboratory studies, the acidity measured in breeding ponds should cause mortality in A. maculatum and permit normal development in A. jeffersonianum. In a 4 yr study of a large, acidic vernal pond, 938 adult A. maculatum produced 486 metamorphosed juveniles (0.52 juvenile/adult), while 686 adult A. jeffersonianum produced 2157 juveniles (3.14 juveniles/adult). Because the effects of acid precipitation on the salamanders' breeding ponds are cumulative from year to year, profound changes in the salamander populations can be anticipated.

  10. 2020 Focus briefs on the world's poor and hungry people:

    OpenAIRE

    IFPRI

    2007-01-01

    Contents: 1.The Changing Profile of Poverty in the World/Shaohua Chen and Martin Ravallion. 2.Characteristics and Causes of Severe Poverty and Hunger/Akhter U. Ahmed, Ruth Vargas Hill, Lisa C. Smith, and Tim Frankenberger. 3.The Poorest and Hungry: Looking Below the Line/Akhter U. Ahmed, Ruth Vargas Hill, and Doris M. Wiesmann. 4.Mapping Where the Poor Live/Todd Benson, Michael Epprecht, and Nicholas Minot 5.Child Malnutrition in India and China/Peter Svedberg. 6.Poverty and the Globalization...

  11. Data on chemical activation of Wnt/β-catenin during axolotl limb regeneration

    Directory of Open Access Journals (Sweden)

    Sabina Wischin

    2017-04-01

    Full Text Available Limb amputation in axolotls was performed to obtain data demonstrating that a chemical agonist of Wnt (int-related protein/β-catenin signalling can have a role in axolotl limb regeneration (Wischin et al., 2017 [1]. The data revealed that active β-catenin protein was present during limb regeneration in some Leydig cells in the epithelium; after the chemical treatment, it was observed in more Leydig cells. In addition, the chemical agonist of Wnt generated distinct limb malformation.

  12. Comparison of tissue processing methods for microvascular visualization in axolotls.

    Science.gov (United States)

    Montoro, Rodrigo; Dickie, Renee

    2017-01-01

    The vascular system, the pipeline for oxygen and nutrient delivery to tissues, is essential for vertebrate development, growth, injury repair, and regeneration. With their capacity to regenerate entire appendages throughout their lifespan, axolotls are an unparalleled model for vertebrate regeneration, but they lack many of the molecular tools that facilitate vascular imaging in other animal models. The determination of vascular metrics requires high quality image data for the discrimination of vessels from background tissue. Quantification of the vasculature using perfused, cleared specimens is well-established in mammalian systems, but has not been widely employed in amphibians. The objective of this study was to optimize tissue preparation methods for the visualization of the microvascular network in axolotls, providing a basis for the quantification of regenerative angiogenesis. To accomplish this aim, we performed intracardiac perfusion of pigment-based contrast agents and evaluated aqueous and non-aqueous clearing techniques. The methods were verified by comparing the quality of the vascular images and the observable vascular density across treatment groups. Simple and inexpensive, these tissue processing techniques will be of use in studies assessing vascular growth and remodeling within the context of regeneration. Advantages of this method include: •Higher contrast of the vasculature within the 3D context of the surrounding tissue •Enhanced detection of microvasculature facilitating vascular quantification •Compatibility with other labeling techniques.

  13. Temperature and ontogenetic effects on color change in the larval salamander species Ambystoma barbouri and Ambystoma texanum

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, T S; Straus, R; Sih, A [Univ. of Kentucky, Dept. of Biological Sciences, Lexington, Kentucky (United States)

    2003-04-01

    Temperature has been shown to affect body color in several species of amphibians. The interaction between color and temperature may also change over larval ontogeny, perhaps because of age-related or seasonal changes in selection pressures on color. We quantified the effects of temperature on the color of the salamander sister species Ambystoma barbouri and Ambystoma texanum over larval ontogeny. We found that early-stage larvae responded to cold temperatures with a dark color relative to that of the warm temperature response. Both species then exhibited an ontogenetic shift in larval color, with larvae becoming lighter with age. Interestingly, older larvae showed decreased plasticity in color change to temperature when compared with younger stages. Older A. texanum larvae exhibited a reversal in the direction of color change, with cold temperatures inducing a lighter color relative to warm temperatures. We suggest that the overall pattern of color change (a plastic color response to temperature for young larvae, a progressive lightening of larvae over development, and an apparent loss of color plasticity to temperature over ontogeny) can be plausibly explained by seasonal changes in environmental factors (temperature, ultraviolet radiation) selecting for body color. (author)

  14. Temperature and ontogenetic effects on color change in the larval salamander species Ambystoma barbouri and Ambystoma texanum

    International Nuclear Information System (INIS)

    Garcia, T.S.; Straus, R.; Sih, A.

    2003-01-01

    Temperature has been shown to affect body color in several species of amphibians. The interaction between color and temperature may also change over larval ontogeny, perhaps because of age-related or seasonal changes in selection pressures on color. We quantified the effects of temperature on the color of the salamander sister species Ambystoma barbouri and Ambystoma texanum over larval ontogeny. We found that early-stage larvae responded to cold temperatures with a dark color relative to that of the warm temperature response. Both species then exhibited an ontogenetic shift in larval color, with larvae becoming lighter with age. Interestingly, older larvae showed decreased plasticity in color change to temperature when compared with younger stages. Older A. texanum larvae exhibited a reversal in the direction of color change, with cold temperatures inducing a lighter color relative to warm temperatures. We suggest that the overall pattern of color change (a plastic color response to temperature for young larvae, a progressive lightening of larvae over development, and an apparent loss of color plasticity to temperature over ontogeny) can be plausibly explained by seasonal changes in environmental factors (temperature, ultraviolet radiation) selecting for body color. (author)

  15. An Ambystoma mexicanum EST sequencing project: analysis of 17,352 expressed sequence tags from embryonic and regenerating blastema cDNA libraries

    Science.gov (United States)

    Habermann, Bianca; Bebin, Anne-Gaelle; Herklotz, Stephan; Volkmer, Michael; Eckelt, Kay; Pehlke, Kerstin; Epperlein, Hans Henning; Schackert, Hans Konrad; Wiebe, Glenis; Tanaka, Elly M

    2004-01-01

    Background The ambystomatid salamander, Ambystoma mexicanum (axolotl), is an important model organism in evolutionary and regeneration research but relatively little sequence information has so far been available. This is a major limitation for molecular studies on caudate development, regeneration and evolution. To address this lack of sequence information we have generated an expressed sequence tag (EST) database for A. mexicanum. Results Two cDNA libraries, one made from stage 18-22 embryos and the other from day-6 regenerating tail blastemas, generated 17,352 sequences. From the sequenced ESTs, 6,377 contigs were assembled that probably represent 25% of the expressed genes in this organism. Sequence comparison revealed significant homology to entries in the NCBI non-redundant database. Further examination of this gene set revealed the presence of genes involved in important cell and developmental processes, including cell proliferation, cell differentiation and cell-cell communication. On the basis of these data, we have performed phylogenetic analysis of key cell-cycle regulators. Interestingly, while cell-cycle proteins such as the cyclin B family display expected evolutionary relationships, the cyclin-dependent kinase inhibitor 1 gene family shows an unusual evolutionary behavior among the amphibians. Conclusions Our analysis reveals the importance of a comprehensive sequence set from a representative of the Caudata and illustrates that the EST sequence database is a rich source of molecular, developmental and regeneration studies. To aid in data mining, the ESTs have been organized into an easily searchable database that is freely available online. PMID:15345051

  16. Annual air pollution caused by the Hungry Ghost Festival.

    Science.gov (United States)

    Khezri, B; Chan, Y Y; Tiong, L Y D; Webster, R D

    2015-09-01

    Burning of joss paper and incense is still a very common traditional custom in countries with a majority Chinese population. The Hungry Ghost Festival which is celebrated in the 7 month of the Chinese calendar is one of the events where joss paper and incense are burned as offerings. This study investigates the impact of the Ghost Month Festival (open burning event) on air quality by analysis of the chemical composition of particulate matter (PM) and rainwater samples collected during this event, compared with data collected throughout the year, as well as bottom ash samples from burning the original joss paper and incense. The results showed that the change in the chemical composition of the rainwater and PM2.5 (PM ≤ 2.5 μm) atmospheric samples could be correlated directly with burning events during this festival, with many elements increasing between 18% and 60% during August and September compared to the yearly mean concentrations. The order of percentage increase in elemental composition (in rain water and PM2.5) during the Hungry Ghost Festival is as follows: Zn > Ca > K > Mg > Fe > Al > Na ∼ Mn ∼ Ti ∼ V > Cu > As > Ni > Co > Cd > Cr > Pb. The chemical composition of the original source materials (joss paper and incense for combustion) and their associated bottom ash were analysed to explain the impact of burning on air quality.

  17. Hungry Horse Mitigation : Flathead Lake : Annual Progress Report 2008.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Barry; Evarts, Les [Confederated Salish and Kootenai Tribes

    2009-08-06

    The Confederated Salish and Kootenai Tribes (CSKT) and Montana Fish Wildlife and Parks (MFWP) wrote the 'Fisheries Mitigation Plan for Losses Attributable to the Construction and Operation of Hungry Horse Dam' in March 1991 to define the fisheries losses, mitigation alternatives and recommendations to protect, mitigate and enhance resident fish and aquatic habitat affected by Hungry Horse Dam. On November 12, 1991, the Northwest Power Planning Council (NPPC) approved the mitigation plan with minor modifications, called for a detailed implementation plan, and amended measures 903(h)(1) through (7). A long-term mitigation plan was submitted in August 1992, was approved by the Council in 1993, and the first contract for this project was signed on November 11, 1993. The problem this project addresses is the loss of habitat, both in quality and quantity, in the Flathead Lake and River basin resulting from the construction and operation of Hungry Horse Dam. The purpose of the project is to both implement mitigation measures and monitor the biological responses to those measures including those implemented by Project Numbers 9101903 and 9101904. Goals and objectives of the 1994 Fish and Wildlife Program (Section 10.1) addressed by this project are the rebuilding to sustainable levels weak, but recoverable, native populations injured by the hydropower system. The project mitigates the blockage of spawning runs by Hungry Horse Dam by restoring and even creating spawning habitats within direct drainages to Flathead Lake. The project also addresses the altered habitat within Flathead Lake resulting from species shifts and consequent dominance of new species that restricts the potential success of mitigation measures. Specific goals of this project are to create and restore habitat and quantitatively monitor changes in fish populations to verify the efficacy of our mitigation measures. The project consists of three components: monitoring, restoration and research

  18. Hungry Horse Mitigation : Flathead Lake : Annual Progress Report 2007.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Barry; Evarts, Les [Confederated Salish and Kootenai Tribes

    2008-12-22

    The Confederated Salish and Kootenai Tribes (CSKT) and Montana Fish Wildlife and Parks (MFWP) wrote the 'Fisheries Mitigation Plan for Losses Attributable to the Construction and Operation of Hungry Horse Dam' in March 1991 to define the fisheries losses, mitigation alternatives and recommendations to protect, mitigate and enhance resident fish and aquatic habitat affected by Hungry Horse Dam. On November 12, 1991, the Northwest Power Planning Council (NPPC) approved the mitigation plan with minor modifications, called for a detailed implementation plan, and amended measures 903(h)(1) through (7). A long-term mitigation plan was submitted in August 1992, was approved by the Council in 1993, and the first contract for this project was signed on November 11, 1993. The problem this project addresses is the loss of habitat, both in quality and quantity, in the Flathead Lake and River basin resulting from the construction and operation of Hungry Horse Dam. The purpose of the project is to both implement mitigation measures and monitor the biological responses to those measures including those implemented by Project Numbers 9101903 and 9101904. Goals and objectives of the 1994 Fish and Wildlife Program (Section 10.1) addressed by this project are the rebuilding to sustainable levels weak, but recoverable, native populations injured by the hydropower system. The project mitigates the blockage of spawning runs by Hungry Horse Dam by restoring and even creating spawning habitats within direct drainages to Flathead Lake. The project also addresses the altered habitat within Flathead Lake resulting from species shifts and consequent dominance of new species that restricts the potential success of mitigation measures. Specific goals of this project are to create and restore habitat and quantitatively monitor changes in fish populations to verify the efficacy of our mitigation measures. The project consists of three components: monitoring, restoration and research

  19. Network based transcription factor analysis of regenerating axolotl limbs

    Directory of Open Access Journals (Sweden)

    Cameron Jo Ann

    2011-03-01

    Full Text Available Abstract Background Studies on amphibian limb regeneration began in the early 1700's but we still do not completely understand the cellular and molecular events of this unique process. Understanding a complex biological process such as limb regeneration is more complicated than the knowledge of the individual genes or proteins involved. Here we followed a systems biology approach in an effort to construct the networks and pathways of protein interactions involved in formation of the accumulation blastema in regenerating axolotl limbs. Results We used the human orthologs of proteins previously identified by our research team as bait to identify the transcription factor (TF pathways and networks that regulate blastema formation in amputated axolotl limbs. The five most connected factors, c-Myc, SP1, HNF4A, ESR1 and p53 regulate ~50% of the proteins in our data. Among these, c-Myc and SP1 regulate 36.2% of the proteins. c-Myc was the most highly connected TF (71 targets. Network analysis showed that TGF-β1 and fibronectin (FN lead to the activation of these TFs. We found that other TFs known to be involved in epigenetic reprogramming, such as Klf4, Oct4, and Lin28 are also connected to c-Myc and SP1. Conclusions Our study provides a systems biology approach to how different molecular entities inter-connect with each other during the formation of an accumulation blastema in regenerating axolotl limbs. This approach provides an in silico methodology to identify proteins that are not detected by experimental methods such as proteomics but are potentially important to blastema formation. We found that the TFs, c-Myc and SP1 and their target genes could potentially play a central role in limb regeneration. Systems biology has the potential to map out numerous other pathways that are crucial to blastema formation in regeneration-competent limbs, to compare these to the pathways that characterize regeneration-deficient limbs and finally, to identify stem

  20. Transforming growth factor: beta signaling is essential for limb regeneration in axolotls.

    Directory of Open Access Journals (Sweden)

    Mathieu Lévesque

    2007-11-01

    Full Text Available Axolotls (urodele amphibians have the unique ability, among vertebrates, to perfectly regenerate many parts of their body including limbs, tail, jaw and spinal cord following injury or amputation. The axolotl limb is the most widely used structure as an experimental model to study tissue regeneration. The process is well characterized, requiring multiple cellular and molecular mechanisms. The preparation phase represents the first part of the regeneration process which includes wound healing, cellular migration, dedifferentiation and proliferation. The redevelopment phase represents the second part when dedifferentiated cells stop proliferating and redifferentiate to give rise to all missing structures. In the axolotl, when a limb is amputated, the missing or wounded part is regenerated perfectly without scar formation between the stump and the regenerated structure. Multiple authors have recently highlighted the similarities between the early phases of mammalian wound healing and urodele limb regeneration. In mammals, one very important family of growth factors implicated in the control of almost all aspects of wound healing is the transforming growth factor-beta family (TGF-beta. In the present study, the full length sequence of the axolotl TGF-beta1 cDNA was isolated. The spatio-temporal expression pattern of TGF-beta1 in regenerating limbs shows that this gene is up-regulated during the preparation phase of regeneration. Our results also demonstrate the presence of multiple components of the TGF-beta signaling machinery in axolotl cells. By using a specific pharmacological inhibitor of TGF-beta type I receptor, SB-431542, we show that TGF-beta signaling is required for axolotl limb regeneration. Treatment of regenerating limbs with SB-431542 reveals that cellular proliferation during limb regeneration as well as the expression of genes directly dependent on TGF-beta signaling are down-regulated. These data directly implicate TGF

  1. Infection of spotted salamanders (Ambystoma maculatum) with Ichthyophonus-like organisms in Virginia.

    Science.gov (United States)

    Ware, Joy L; Viverette, Cathy; Kleopfer, John D; Pletcher, Leeanna; Massey, Davis; Wright, Anne

    2008-01-01

    Ichthyophonus-like organisms were found in two free-ranging adult spotted salamanders (Ambystoma maculatum) captured within two different vernal ponds in the Virginia Commonwealth University Rice Center for Environmental Life Sciences in Charles City County, Virginia. Histopathologic examination of necropsied specimens revealed large spores, often enclosed by granulomas. These enclosed spores resembled those caused by the fish pathogen Ichthyophonus hoeferi. One salamander displayed an externally visible large swelling beneath the jaws. The other lacked macroscopic abnormalities, but histologic sections of ventral muscle revealed early-stage Ichthyophonus-like organisms and minimal granulomatous reactions. This is the first report of Ichthyophonus-like infection of Ambystoma maculatum in Virginia.

  2. Food loss in a hungry world, a problem?

    Directory of Open Access Journals (Sweden)

    Natalia Martínez Z.

    2014-08-01

    Full Text Available Mainly in developing countries, food loss and waste is a problem that is difficult to measure. Investigations have been conducted in industrialized countries; however, consistent evidence of how much is really being depleted is limited. The accessible data give the illusion of evidence, but are supported by very restricted facts. In recent years, food waste and loss have gained importance because more than 35% of food is wasted. Nevertheless, with this percentage of food, most of the 800 million people that go hungry every day in the world could be fed. This reflection paper aims to describe the different approaches and meanings of food waste, food loss and food wastage. Similarly, this article identifies the phases of the food supply chain where food is being lost and wasted. Based on the available data, developed and developing countries are compared. It was concluded that, in developed countries, the most important losses are in the consumption phase; in developing countries, the losses take place in the growing and harvesting phase. Changing consumption habits as well as the improvement of cropping and harvesting processes could be an option for reducing this problem, especially in developing countries.

  3. Axolotl/Bichos Raros Crónica

    Directory of Open Access Journals (Sweden)

    Susana Chávez-Silverman

    2012-11-01

    Full Text Available In this crónica, I pay homage (and talk back to! one of my favourite authors, Julio Cortázar, who I had the great privilege and pleasure of befriending in 1980, when he was a visiting professor at UC-Berkeley. I have been obsessed with time-travel, doubling, and interstitiality since I was very young; even the most casual Cortázar reader (if such a thing is possible will immediately recognise these as recurrent themes in his work. Here, faced with several actual axolotl in a Buenos Aires aquarium, I explore and comment on Cortázar’s strangely mesmerising meditation on identity and transformation. My personal connection is (as in much of my writing concerned with aspects of gender and sexuality suppressed or (more likely ignored in Cortázar’s version. I identify, too, with a poignant in-betweenness and ambiguity I read in the figure of the axolotl—and in the work of Cortázar and Alejandra Pizarnik.

  4. Enzyme clusters during the metamorphic period of Ambystoma mexicanum: role of thyroid hormone

    NARCIS (Netherlands)

    Lamers, W. H.; Mooren, P. G.; de Graaf, A.

    1982-01-01

    Enzyme activities and DNA content have been measure in axolotl liver during the metamorphic period (4-8 months after spawning). Three different types of enzyme activity profiles were observed. In the type I profile (carbamoyl-phosphate synthase, arginase, ornithine transcarbamoylase, and glutamate

  5. Multiple regeneration from axolotl limb stumps bearing cross-transplanted minced muscle regenerates : brief note

    NARCIS (Netherlands)

    Carlson, Bruce M.

    Flexor and extensor muscles in the upper arms of axolotls were minced and cross-transplanted. The limbs were amputated 5 and 30 days after mincing. In each experiment a high percentage of the regenerates consisted of multiple limbs. This demonstrates that the morphogenetic information which produces

  6. Reproductive biology of Ambystoma salamanders in the southeastern United States

    Science.gov (United States)

    Glorioso, Brad M.; Waddle, J. Hardin; Hefner, J. M.

    2015-01-01

    Reproductive aspects of Ambystoma salamanders were investigated at sites in Louisiana (2010–12) and Mississippi (2013). Three species occurred at the Louisiana site, Spotted Salamander (A. maculatum), Marbled Salamander (A. opacum), and Mole Salamander (A. talpoideum), whereas only Spotted Salamanders were studied at the Mississippi site. A total of 162 and 71 egg masses of Spotted Salamanders were examined at the Louisiana and Mississippi sites, respectively. Significantly more Spotted Salamander eggs per egg mass were observed at the Mississippi site (x̄ = 78.2) than the Louisiana site (x̄ = 53.8; P < 0.001). The mean snout–vent length of female Spotted Salamanders at the Mississippi site (82.9 mm) was significantly larger than the Louisiana site (76.1 mm; P < 0.001). Opaque Spotted Salamander egg masses were not found at the Mississippi site, but accounted for 11% of examined egg masses at the Louisiana site. The mean number of eggs per egg mass at the Louisiana site did not differ between opaque (47.3) and clear (54.6) egg masses (P = 0.21). A total of 47 egg masses of the Mole Salamander were examined, with a mean number of 6.7 embryos per mass. Twenty-three individual nests of the Marbled Salamander were found either under or in decaying logs in the dry pond basins. There was no difference between the mean numbers of eggs per mass of attended nests (93.0) versus those that were discovered unattended (86.6; P = 0.67). Females tended to place their nests at intermediate heights within the pond basin.

  7. Proteomic analysis of blastema formation in regenerating axolotl limbs

    Directory of Open Access Journals (Sweden)

    Nye Holly LD

    2009-11-01

    Full Text Available Abstract Background Following amputation, urodele salamander limbs reprogram somatic cells to form a blastema that self-organizes into the missing limb parts to restore the structure and function of the limb. To help understand the molecular basis of blastema formation, we used quantitative label-free liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS-based methods to analyze changes in the proteome that occurred 1, 4 and 7 days post amputation (dpa through the mid-tibia/fibula of axolotl hind limbs. Results We identified 309 unique proteins with significant fold change relative to controls (0 dpa, representing 10 biological process categories: (1 signaling, (2 Ca2+ binding and translocation, (3 transcription, (4 translation, (5 cytoskeleton, (6 extracellular matrix (ECM, (7 metabolism, (8 cell protection, (9 degradation, and (10 cell cycle. In all, 43 proteins exhibited exceptionally high fold changes. Of these, the ecotropic viral integrative factor 5 (EVI5, a cell cycle-related oncoprotein that prevents cells from entering the mitotic phase of the cell cycle prematurely, was of special interest because its fold change was exceptionally high throughout blastema formation. Conclusion Our data were consistent with previous studies indicating the importance of inositol triphosphate and Ca2+ signaling in initiating the ECM and cytoskeletal remodeling characteristic of histolysis and cell dedifferentiation. In addition, the data suggested that blastema formation requires several mechanisms to avoid apoptosis, including reduced metabolism, differential regulation of proapoptotic and antiapoptotic proteins, and initiation of an unfolded protein response (UPR. Since there is virtually no mitosis during blastema formation, we propose that high levels of EVI5 function to arrest dedifferentiated cells somewhere in the G1/S/G2 phases of the cell cycle until they have accumulated under the wound epidermis and enter mitosis in response to

  8. Anatomy of the pectoral and forelimb muscles of wildtype and green fluorescent protein-transgenic axolotls and comparison with other tetrapods including humans: a basis for regenerative, evolutionary and developmental studies

    Science.gov (United States)

    Diogo, R; Tanaka, E M

    2012-01-01

    The axolotl Ambystoma mexicanum is one of the most used model organisms in evolutionary, developmental and regenerative studies, particularly because it can reconstitute a fully functional and complete forelimb/hindlimb. Surprisingly, there is no publication that describes all the pectoral and forelimb muscles of this species or provides a comparative framework between these muscles and those of other model organisms and of modern humans. In the present paper we describe and illustrate all these muscles in A. mexicanum and provide the first report about the myology of adults of a model organism that is based on analyses and dissections of both wildtype animals and transgenic animals that express green fluorescent protein (GFP) in muscle fibers. On the one hand, the inclusion of GFP-transgenic animals allows us to show the muscles as more commonly seen, and thus easier to understand, by current developmental and regenerative biologists. On the other hand, by including wildtype and GFP-transgenic animals and by visualizing these latter animals with and without a simultaneous transmission laser light, we were able to obtain a more complete and clearer understanding of the exact limit of the fleshy and tendinous parts of the muscles and their specific connections with the skeletal elements. This in turn allowed us to settle some controversies in previous anatomical and comparative studies. As most developmental, regenerative and evolutionary biologists are interested in comparing their observations of A. mexicanum with observations in other model organisms, and ultimately in using this information to increase the understanding of human evolution and medicine, we also provide tables showing the homologies between the pectoral and forelimb muscles of axolotls, of model organisms such as mice, frogs and chicken, and of Homo sapiens. An example illustrating the outcomes of using our methodology and of our observations is that they revealed that, contrary to what is often

  9. Anatomy of the pectoral and forelimb muscles of wildtype and green fluorescent protein-transgenic axolotls and comparison with other tetrapods including humans: a basis for regenerative, evolutionary and developmental studies.

    Science.gov (United States)

    Diogo, R; Tanaka, E M

    2012-12-01

    The axolotl Ambystoma mexicanum is one of the most used model organisms in evolutionary, developmental and regenerative studies, particularly because it can reconstitute a fully functional and complete forelimb/hindlimb. Surprisingly, there is no publication that describes all the pectoral and forelimb muscles of this species or provides a comparative framework between these muscles and those of other model organisms and of modern humans. In the present paper we describe and illustrate all these muscles in A. mexicanum and provide the first report about the myology of adults of a model organism that is based on analyses and dissections of both wildtype animals and transgenic animals that express green fluorescent protein (GFP) in muscle fibers. On the one hand, the inclusion of GFP-transgenic animals allows us to show the muscles as more commonly seen, and thus easier to understand, by current developmental and regenerative biologists. On the other hand, by including wildtype and GFP-transgenic animals and by visualizing these latter animals with and without a simultaneous transmission laser light, we were able to obtain a more complete and clearer understanding of the exact limit of the fleshy and tendinous parts of the muscles and their specific connections with the skeletal elements. This in turn allowed us to settle some controversies in previous anatomical and comparative studies. As most developmental, regenerative and evolutionary biologists are interested in comparing their observations of A. mexicanum with observations in other model organisms, and ultimately in using this information to increase the understanding of human evolution and medicine, we also provide tables showing the homologies between the pectoral and forelimb muscles of axolotls, of model organisms such as mice, frogs and chicken, and of Homo sapiens. An example illustrating the outcomes of using our methodology and of our observations is that they revealed that, contrary to what is often

  10. Cartilage and bone cells do not participate in skeletal regeneration in Ambystoma mexicanum limbs.

    Science.gov (United States)

    McCusker, Catherine D; Diaz-Castillo, Carlos; Sosnik, Julian; Q Phan, Anne; Gardiner, David M

    2016-08-01

    The Mexican Axolotl is one of the few tetrapod species that is capable of regenerating complete skeletal elements in injured adult limbs. Whether the skeleton (bone and cartilage) plays a role in the patterning and contribution to the skeletal regenerate is currently unresolved. We tested the induction of pattern formation, the effect on cell proliferation, and contributions of skeletal tissues (cartilage, bone, and periosteum) to the regenerating axolotl limb. We found that bone tissue grafts from transgenic donors expressing GFP fail to induce pattern formation and do not contribute to the newly regenerated skeleton. Periosteum tissue grafts, on the other hand, have both of these activities. These observations reveal that skeletal tissue does not contribute to the regeneration of skeletal elements; rather, these structures are patterned by and derived from cells of non-skeletal connective tissue origin. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Aid as Obstacle: Twenty Questions about Our Foreign Aid and the Hungry.

    Science.gov (United States)

    Lappe, Frances Moore; And Others

    Reasons why U.S. foreign aid fails to alleviate hunger and poverty are discussed and a solution to the problem is presented. The United States now channels more foreign aid than ever to the world's poor and hungry through the Agency for International Development, food aid programs, the World Bank, and other multilateral aid agencies, which report…

  12. A brief mindfulness intervention reduces unhealthy eating when hungry, but not the portion size effect

    NARCIS (Netherlands)

    Marchiori, D.R.; Papies, E.K.

    2014-01-01

    Objective: The present research examined the effects of a mindfulness-based intervention to foster healthy eating. Specifically, we tested whether a brief mindfulness manipulation can prevent the portion size effect, and reduce overeating on unhealthy snacks when hungry. Methods: 110 undergraduate

  13. Expression of Msx-2 during development, regeneration, and wound healing in axolotl limbs.

    Science.gov (United States)

    Carlson, M R; Bryant, S V; Gardiner, D M

    1998-12-15

    Msx genes are transcription factors that are expressed during embryogenesis of developing appendages in regions of epithelial-mesenchymal interactions. Various lines of evidence indicate that these genes function to maintain embryonic tissues in an undifferentiated, proliferative state. We have identified the axolotl homolog of Msx-2, and investigated its expression during limb development, limb regeneration, and wound healing. As in limb buds of higher vertebrates, axolotl Msx-2 is expressed in the apical epidermis and mesenchyme; however, its expression domain is more extensive, reflecting the broader region of the apical epidermal cap in amphibians. Msx-2 expression is downregulated at late stages of limb development, but is reexpressed within one hour after limb amputation. Msx-2 is also reexpressed during wound healing, and may be essential in the early stages of initiation of the limb regeneration cascade.

  14. Regulation of antibody synthesis in the X-irradiated Mexican axolotl

    International Nuclear Information System (INIS)

    Charlemagne, J.

    1981-01-01

    The effects of X-irradiation were studied on the Mexican axolotl antibody synthesis. To reduce the anti-horse red blood cell (HRBC) antibody titers, 150 rd and smaller doses are ineffective, 200-450 rd are increasingly effective, and 700 rd are maximally effective (and lethal). A significant enhancement of the anti-HRBC titers was observed in low doses (50-150 rd X-irradiated animals). This enhancement was also observed when a low X-ray dose was applied only on the thymic areas. In whole body, but thymus area-shielded, 100 rd X-irradiated animals, the anti-HRBC titers were similar to those of the nonirradiated, HRBC-immunized control group. To explain these phenomena, it is suggested that a radiosensitive, adult thymectomy-sensitive and hydrocortisone-sensitive suppressor T cell subpopulation regulates the antibody synthesis in the axolotl. (orig.) [de

  15. Regulation of antibody synthesis in the X-irradiated Mexican axolotl

    Energy Technology Data Exchange (ETDEWEB)

    Charlemagne, J.

    1981-09-01

    The effects of X-irradiation were studied on the Mexican axolotl antibody synthesis. To reduce the anti-horse red blood cell (HRBC) antibody titers, 150 rd and smaller doses are ineffective, 200-450 rd are increasingly effective, and 700 rd are maximally effective (and lethal). A significant enhancement of the anti-HRBC titers was observed in low doses (50-150 rd X-irradiated animals). This enhancement was also observed when a low X-ray dose was applied only on the thymic areas. In whole body, but thymus area-shielded, 100 rd X-irradiated animals, the anti-HRBC titers were similar to those of the nonirradiated, HRBC-immunized control group. To explain these phenomena, it is suggested that a radiosensitive, adult thymectomy-sensitive and hydrocortisone-sensitive suppressor T cell subpopulation regulates the antibody synthesis in the axolotl.

  16. Effects of acid precipitation on embryonic mortality of Ambystoma salamanders in the Connecticut Valley of Massachusetts

    Energy Technology Data Exchange (ETDEWEB)

    Cook, R P

    1983-01-01

    An investigation of increased embryonic mortality of the spotted salamander Ambystoma maculatum concomitant with breeding pond acidification from acid rainfall in the Connecticut Valley of Massachusetts analyzes the pH and chemistry of rain and pond water and monitored embryonic mortality in 1976 and 1977. Although acid rain continues to occur in the area and Ambystoma breeding ponds are acidic, the average pH of six ponds dropped from 5.62 to 5.10 during the study. Pond pH decreased up to 0.75 pH units following heavy rainfall. Despite this, embryonic mortality of spotted and Jefferson salamanders was low, and no significant correlation between pond pH and percent embryonic mortality was found. The size of present populations and the embryonic acid tolerance exhibited by the salamander indicate that acid rain has not had an effect in this location. 22 references, 2 figures, 4 tables.

  17. Pathological changes of Golgi complex in hemocytoblasts of spleen of young axolotls after x-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Turska, R.

    1975-01-01

    The data available up to now concerning the structure of Golgi complex in different types of normal and pathologically changed cells are very divergent. Results are reported from detailed studies on changes occurring within the Golgi complex in the spleen of three-month old axolotls after x-ray irradiation with a single dose of 1,200 R and killed by decapitation 15, 30, 60 minutes and 3, 6, and 12 hours after irradiation.

  18. Expression of Msx genes in regenerating and developing limbs of axolotl.

    Science.gov (United States)

    Koshiba, K; Kuroiwa, A; Yamamoto, H; Tamura, K; Ide, H

    1998-12-15

    Msx genes, homeobox-containing genes, have been isolated as homologues of the Drosophila msh gene and are thought to play important roles in the development of chick or mouse limb buds. We isolated two Msx genes, Msx1 and Msx2, from regenerating blastemas of axolotl limbs and examined their expression patterns using Northern blot and whole mount in situ hybridization during regeneration and development. Northern blot analysis revealed that the expression level of both Msx genes increased during limb regeneration. The Msx2 expression level increased in the blastema at the early bud stage, and Msx1 expression level increased at the late bud stage. Whole mount in situ hybridization revealed that Msx2 was expressed in the distal mesenchyme and Msx1 in the entire mesenchyme of the blastema at the late bud stage. In the developing limb bud, Msx1 was expressed in the entire mesenchyme, while Msx2 was expressed in the distal and peripheral mesenchyme. The expression patterns of Msx genes in the blastemas and limb buds of the axolotl were different from those reported for chick or mouse limb buds. These expression patterns of axolotl Msx genes are discussed in relation to the blastema or limb bud morphology and their possible roles in limb patterning.

  19. Hungry Horse Dam Fisheries Mitigation Implementation Plan, 1990-2003 Progress (Annual) Report.

    Energy Technology Data Exchange (ETDEWEB)

    Montana Department of Fish, Wildlife and Parks; Confederated Salish and Kootenai Tribes

    1993-03-10

    In this document the authors present mitigation implementation activities to protect and enhance resident fish and aquatic habitat affected by the construction and operation of Hungry Horse Dam. This plan only addresses non-operational actions (mitigation measures that do not affect dam operation) described in the 'Fisheries Mitigation Plan for Losses Attributable to the Construction and Operation of Hungry Horse Dam' (Mitigation Plan) submitted to the Northwest Power Planning Council (Council) in March 1991 and in accordance with subsequent Council action on that Mitigation Plan. Operational mitigation was deferred for consideration under the Columbia Basin System Operation Review (SOR) process. This document represents an implementation plan considered and conditionally approved by the Council in March of 1993.

  20. A brief mindfulness intervention reduces unhealthy eating when hungry, but not the portion size effect.

    Science.gov (United States)

    Marchiori, David; Papies, Esther K

    2014-04-01

    The present research examined the effects of a mindfulness-based intervention to foster healthy eating. Specifically, we tested whether a brief mindfulness manipulation can prevent the portion size effect, and reduce overeating on unhealthy snacks when hungry. 110 undergraduate participants (MAge=20.9±2.3; MBMI=22.3±2.5) were served a small or a large portion of chocolate chip cookies after listening to an audio book or performing a mindfulness exercise (i.e., body scan). Current level of hunger was assessed unobtrusively on a visual analog scale before the eating situation. Calorie intake from chocolate chip cookies. When presented with a large compared to a small portion, participants consumed more cookies (+83kcal). This was not affected by the mindfulness intervention or by hunger. However, while control participants ate more unhealthy food when hungry than when not hungry (+67kcal), participants in the mindfulness condition did not (+1kcal). Findings confirm the prevalence and robustness of the portion size effect and suggest that it may be independent from awareness of internal cues. Prevention strategies may benefit more from targeting awareness of the external environment. However, mindfulness-based interventions may be effective to reduce effects of hunger on unhealthy food consumption. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Virtual Genome Walking across the 32 Gb Ambystoma mexicanum genome; assembling gene models and intronic sequence.

    Science.gov (United States)

    Evans, Teri; Johnson, Andrew D; Loose, Matthew

    2018-01-12

    Large repeat rich genomes present challenges for assembly using short read technologies. The 32 Gb axolotl genome is estimated to contain ~19 Gb of repetitive DNA making an assembly from short reads alone effectively impossible. Indeed, this model species has been sequenced to 20× coverage but the reads could not be conventionally assembled. Using an alternative strategy, we have assembled subsets of these reads into scaffolds describing over 19,000 gene models. We call this method Virtual Genome Walking as it locally assembles whole genome reads based on a reference transcriptome, identifying exons and iteratively extending them into surrounding genomic sequence. These assemblies are then linked and refined to generate gene models including upstream and downstream genomic, and intronic, sequence. Our assemblies are validated by comparison with previously published axolotl bacterial artificial chromosome (BAC) sequences. Our analyses of axolotl intron length, intron-exon structure, repeat content and synteny provide novel insights into the genic structure of this model species. This resource will enable new experimental approaches in axolotl, such as ChIP-Seq and CRISPR and aid in future whole genome sequencing efforts. The assembled sequences and annotations presented here are freely available for download from https://tinyurl.com/y8gydc6n . The software pipeline is available from https://github.com/LooseLab/iterassemble .

  2. Comparative RNA-seq analysis in the unsequenced axolotl: the oncogene burst highlights early gene expression in the blastema.

    Directory of Open Access Journals (Sweden)

    Ron Stewart

    Full Text Available The salamander has the remarkable ability to regenerate its limb after amputation. Cells at the site of amputation form a blastema and then proliferate and differentiate to regrow the limb. To better understand this process, we performed deep RNA sequencing of the blastema over a time course in the axolotl, a species whose genome has not been sequenced. Using a novel comparative approach to analyzing RNA-seq data, we characterized the transcriptional dynamics of the regenerating axolotl limb with respect to the human gene set. This approach involved de novo assembly of axolotl transcripts, RNA-seq transcript quantification without a reference genome, and transformation of abundances from axolotl contigs to human genes. We found a prominent burst in oncogene expression during the first day and blastemal/limb bud genes peaking at 7 to 14 days. In addition, we found that limb patterning genes, SALL genes, and genes involved in angiogenesis, wound healing, defense/immunity, and bone development are enriched during blastema formation and development. Finally, we identified a category of genes with no prior literature support for limb regeneration that are candidates for further evaluation based on their expression pattern during the regenerative process.

  3. The effects of rotation and positional change of stump tissues upon morphogenesis of the regenerating axolotl limb

    NARCIS (Netherlands)

    Carlson, Bruce M.

    1972-01-01

    Rotation of a skin cuff 180° around the proximodistal axis of the upper arm in the axolotl results in the formation of multiple regenerates in about 80° of cases after amputation of the limb through the rotated skin. Rotation of the dermis or the flexor and extensor muscles folowed by amputation

  4. Intracellular ionic compartmentation, electrical membrane properties, and cell membrane permeability before and during first cleavage in the Ambystoma egg

    NARCIS (Netherlands)

    Laat, S.W. de; Wouters, W.; Silva Pimenta Guarda, M.M. Marques da; Silva Guarda, M.A. da

    The intracellular ionic distribution in uncleaved and cleaving Ambystoma eggs was investigated by analysing the influx of 3H2O, by determining the total content of Na+, K+ and Cl− in extracts of eggs at different stages by both flame spectrophotometry and ion-selective microelectrodes, and by the

  5. Hungry Horse Mitigation Plan; Fisheries Mitigation Plan for Losses Attributable to the Construction and Operation of Hungry Horse Dam, 1990-2003 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Fraley, John J.; Marotz, Brian L. (Montana Department of Fish, Wildlife and Parks, Helena, MT); DosSantos, Joseph M. (Confederated Salish and Kootenai Tribes of the Flathead Nation, Pablo, MT)

    2003-04-01

    In this document we present fisheries losses, mitigation alternatives, and recommendations to protect, mitigate, and enhance resident fish and aquatic habitat affected by the construction and operation of Hungry Horse Dam. This plan addresses six separate program measures in the 1987 Columbia Basin Fish and Wildlife Program. We designed the plan to be closely coordinated in terms of dam operations, funding, and activities with the Kerr Mitigation Plan presently before the Federal Energy Regulatory Commission. This document represents a mitigation plan for consideration by the Northwest Power Planning Council process; it is not an implementation plan. Flathead Lake is one of the cleanest lakes of its size in the world. The exceptional water quality and unique native fisheries make the Flathead Lake/River system extremely valuable to the economy and quality of life in the basin. The recreational fishery in Flathead Lake has an estimated value of nearly eight million dollars annually. This mitigation process represents our best opportunity to reduce the impacts of hydropower in this valuable aquatic system and increase angling opportunity. We based loss estimates and mitigation alternatives on an extensive data base, agency reports, nationally and internationally peer-reviewed scientific articles, and an innovative biological model for Hungry Horse Reservoir and the Flathead River. We conducted an extensive, 14-month scoping and consultation process with agency representatives, representatives of citizen groups, and the general public. This consultation process helped identify issues, areas of agreement, areas of conflict, and advantages and disadvantages of mitigation alternatives. The results of the scoping and consultation process helped shape our mitigation plan. Our recommended plan is based firmly on principles of adaptive management and recognition of biological uncertainty. After we receive direction from the NPPC, we will add more detailed hypotheses and

  6. Time--temperature relation of embryonic development in the northwestern salamander, Ambystoma gracile

    Energy Technology Data Exchange (ETDEWEB)

    Brown, H A

    1976-04-01

    A field and laboratory study on temperature-related embryonic development of Ambystoma gracile was made on a population from northwestern Washington. Natural spawning began in the beaver pond during early March, and the duration of embryonic development (stages 1 to 46) was about 62 days. Average water temperature in the pond during embryonic development was 8.5/sup 0/C (range, 4.4 to 14.3/sup 0/C). The laboratory data of embryonic development at constant temperatures show that the limits of temperature tolerance are about 5 to 22.5/sup 0/C. Rate of development was measured by determining time required to develop from first cleavage (stage 2) to gill circulation (stage 37); representative rates are 12.7 days at 20/sup 0/C, 27 days at 12/sup 0/C, and 89 days at 7/sup 0/C. Embryos of A. gracile have the slowest rate of development when compared with embryos of four other species of Ambystoma (maculatum, mexicanum, tigrinum, and jeffersonianum) and with embryos of three Pacific Northwest frogs (Ascaphus truei, Rana aurora, and Hyla regilla).

  7. Temporal response of the tiger salamander (Ambystoma tigrinum to 3,000 years of climatic variation

    Directory of Open Access Journals (Sweden)

    Long Webb

    2005-09-01

    Full Text Available Abstract Background Amphibians are sensitive indicators of environmental conditions and show measurable responses, such as changes in phenology, abundance and range limits to local changes in precipitation and temperature regimes. Amphibians offer unique opportunities to study the important ecological and evolutionary implications of responses in life history characteristics to climatic change. We analyzed a late-Holocene fossil record of the Tiger Salamander (Ambystoma tigrinum for evidence of population-level changes in body size and paedomorphosis to climatic change over the last 3000 years. Results We found a significant difference in body size index between paedomorphic and metamorphic individuals during the time interval dominated by the Medieval Warm Period. There is a consistent ratio of paedomorphic to metamorphic specimens through the entire 3000 years, demonstrating that not all life history characteristics of the population were significantly altered by changes in climate on this timescale. Conclusion The fossil record of Ambystoma tigrinum we used spans an ecologically relevant timescale appropriate for understanding population and community response to projected climatic change. The population-level responses we documented are concordant with expectations based on modern environmental studies, and yield insight into population-level patterns across hundreds of generations, especially the independence of different life history characteristics. These conclusions lead us to offer general predictions about the future response of this species based on likely scenarios of climatic warming in the Rocky Mountain region.

  8. Live Imaging of Axolotl Digit Regeneration Reveals Spatiotemporal Choreography of Diverse Connective Tissue Progenitor Pools.

    Science.gov (United States)

    Currie, Joshua D; Kawaguchi, Akane; Traspas, Ricardo Moreno; Schuez, Maritta; Chara, Osvaldo; Tanaka, Elly M

    2016-11-21

    Connective tissues-skeleton, dermis, pericytes, fascia-are a key cell source for regenerating the patterned skeleton during axolotl appendage regeneration. This complexity has made it difficult to identify the cells that regenerate skeletal tissue. Inability to identify these cells has impeded a mechanistic understanding of blastema formation. By tracing cells during digit tip regeneration using brainbow transgenic axolotls, we show that cells from each connective tissue compartment have distinct spatial and temporal profiles of proliferation, migration, and differentiation. Chondrocytes proliferate but do not migrate into the regenerate. In contrast, pericytes proliferate, then migrate into the blastema and give rise solely to pericytes. Periskeletal cells and fibroblasts contribute the bulk of digit blastema cells and acquire diverse fates according to successive waves of migration that choreograph their proximal-distal and tissue contributions. We further show that platelet-derived growth factor signaling is a potent inducer of fibroblast migration, which is required to form the blastema. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  9. The axolotl limb blastema: cellular and molecular mechanisms driving blastema formation and limb regeneration in tetrapods

    Science.gov (United States)

    McCusker, Catherine; Bryant, Susan V.

    2015-01-01

    Abstract The axolotl is one of the few tetrapods that are capable of regenerating complicated biological structures, such as complete limbs, throughout adulthood. Upon injury the axolotl generates a population of regeneration‐competent limb progenitor cells known as the blastema, which will grow, establish pattern, and differentiate into the missing limb structures. In this review we focus on the crucial early events that occur during wound healing, the neural−epithelial interactions that drive the formation of the early blastema, and how these mechanisms differ from those of other species that have restricted regenerative potential, such as humans. We also discuss how the presence of cells from the different axes of the limb is required for the continued growth and establishment of pattern in the blastema as described in the polar coordinate model, and how this positional information is reprogrammed in blastema cells during regeneration. Multiple cell types from the mature limb stump contribute to the blastema at different stages of regeneration, and we discuss the contribution of these types to the regenerate with reference to whether they are “pattern‐forming” or “pattern‐following” cells. Lastly, we explain how an engineering approach will help resolve unanswered questions in limb regeneration, with the goal of translating these concepts to developing better human regenerative therapies. PMID:27499868

  10. Abdominal Distension Associated with Luminal Fungi in the Intestines of Axolotl Larvae

    Directory of Open Access Journals (Sweden)

    Chiara Zullian

    2015-01-01

    Full Text Available Axolotls show a remarkable regeneration capacity compared with higher vertebrates, regenerating missing appendages such as limbs and tail as well as other body parts (i.e., apex of the heart, forebrain, and jaw after amputations which makes this animal a very interesting research model for tissue regeneration mechanisms. Larvae are individually housed in a 20% Holtfreter’s solution within clear plastic containers. The photoperiod light : darkness cycle is 12 : 12 h. Larvae with a total body length of less than 5 cm are fed once a day with large brine shrimp and blood worm. Albino larvae appeared to have a tendency to exhibit abdominal distention. No clinical signs of illness seemed to be associated with the condition; however, these animals exhibit a relatively slower growth rate. To better characterize this condition, we performed histological sectioning for cross sectional slide preparation on wild type and albino axolotl larvae following euthanasia. The only lesion seen in the albino larvae was a thickened gut wall and the presence of fungi within the intestines. We hypothesize that this may be due to a lower efficacy of the albino larvae’s immune system.

  11. On the participation of irradiated tissues in the formation of limb regenerate in axolotls

    International Nuclear Information System (INIS)

    Tuchkova, S.Ya.

    1976-01-01

    The aim of the study was to obtain further information on the participation of irradiated tissue cells in formation of regenerated limbs after X-irradiation of axolotls and experimental restoration of the regenerational ability. Cells of irradiated tissues were labeled with H 3 -thymidine; the presence of the label in regenerated tissues would be indicative of participation of irradiated cells in the regeneration process. Irradiation dose was 700 R. 30 axolotls with irradiated limbs were intramuscularly injected with rat muscle homogenate into the right limb once a day beginning from the day of treatment. 15 similarly irradiated animals which did not receive homogenate served as a control. The authors concluded that the presence of highly labeled cells in regenerated tissues was likely to indicate the participation of irradiated tissue cells in regeneration of the limb. However, the quantitative contribution of such cells was impossible to determine since remaining irradiated tissues of the organ contained mostly unlabeled cells. It was also impossible to rule out the possibility of cell migration from non-irradiated tissues [ru

  12. Evidence for an RNA polymerization activity in axolotl and Xenopus egg extracts.

    Directory of Open Access Journals (Sweden)

    Hélène Pelczar

    2010-12-01

    Full Text Available We have previously reported a post-transcriptional RNA amplification observed in vivo following injection of in vitro synthesized transcripts into axolotl oocytes, unfertilized (UFE or fertilized eggs. To further characterize this phenomenon, low speed extracts (LSE from axolotl and Xenopus UFE were prepared and tested in an RNA polymerization assay. The major conclusions are: i the amphibian extracts catalyze the incorporation of radioactive ribonucleotide in RNase but not DNase sensitive products showing that these products correspond to RNA; ii the phenomenon is resistant to α-amanitin, an inhibitor of RNA polymerases II and III and to cordycepin (3'dAMP, but sensitive to cordycepin 5'-triphosphate, an RNA elongation inhibitor, which supports the existence of an RNA polymerase activity different from polymerases II and III; the detection of radiolabelled RNA comigrating at the same length as the exogenous transcript added to the extracts allowed us to show that iii the RNA polymerization is not a 3' end labelling and that iv the radiolabelled RNA is single rather than double stranded. In vitro cell-free systems derived from amphibian UFE therefore validate our previous in vivo results hypothesizing the existence of an evolutionary conserved enzymatic activity with the properties of an RNA dependent RNA polymerase (RdRp.

  13. An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors

    Science.gov (United States)

    Srbinovski, Bruno; Magno, Michele; Edwards-Murphy, Fiona; Pakrashi, Vikram; Popovici, Emanuel

    2016-01-01

    Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN) are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA) for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind). Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA) in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources) and power hungry sensors (ultrasonic wind sensor and gas sensors). The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA. PMID:27043559

  14. An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors

    Directory of Open Access Journals (Sweden)

    Bruno Srbinovski

    2016-03-01

    Full Text Available Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind. Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources and power hungry sensors (ultrasonic wind sensor and gas sensors. The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA.

  15. Collagen reconstitution is inversely correlated with induction of limb regeneration in Ambystoma mexicanum.

    Science.gov (United States)

    Satoh, Akira; Hirata, Ayako; Makanae, Aki

    2012-03-01

    Amphibians can regenerate missing body parts, including limbs. The regulation of collagen has been considered to be important in limb regeneration. Collagen deposition is suppressed during limb regeneration, so we investigated collagen deposition and apical epithelial cap (AEC) formation during axolotl limb regeneration. The accessory limb model (ALM) has been developed as an alternative model for studying limb regeneration. Using this model, we investigated the relationship between nerves, epidermis, and collagen deposition. We found that Sp-9, an AEC marker gene, was upregulated by direct interaction between nerves and epidermis. However, collagen deposition hindered this interaction, and resulted in the failure of limb regeneration. During wound healing, an increase in deposition of collagen caused a decrease in the blastema induction rate in ALM. Wound healing and limb regeneration are alternate processes.

  16. Distribution of the Sonora Tiger Salamander (Ambystoma mavortium stebbinsi) in Mexico

    Science.gov (United States)

    Hossack, Blake R.; Muths, Erin L.; Rorabaugh, James C.; Lemos Espinal, Julio A.; Sigafus, Brent H.; Chambert, Thierry A.; Carreon Arroyo, Gerardo; Hurtado Felix, David; Toyos Martinez, Daniel; Jones, Thomas R.

    2016-01-01

    The Sonoran Tiger Salamander (Ambystoma mavortium stebbinsi Lowe, 1954) was listed as federally endangered in the USA in 1997 (USFWS 1997). In the USA, the distribution of A. mavortium stebbinsi is limited to the San Rafael Valley (approximately 567 km2), between the Sierra San Antonio (called the Patagonia Mountains in Arizona) and Huachuca Mountains, and south of the Canelo Hills, Arizona (Fig. 1). The USA listing was triggered by loss of natural wetland habitats, threats from invasive predators, frequent die-offs from disease, introgression with the introduced Barred Tiger Salamander (A. mavortium mavortium), and small range and number of breeding sites that increases susceptibility to stochastic events (USFWS 1997). Small population sizes and limited gene flow have caused inbreeding, which may further reduce population viability and the potential for recovery (Jones et al. 1988; Storfer et al. 2014). 

  17. A retrospective study of diseases in Ambystoma mexicanum: a report of 97 cases.

    Science.gov (United States)

    Takami, Yoshinori; Une, Yumi

    2017-06-16

    Ambystoma mexicanum kept as pets are affected by a variety of diseases. However, no reports regarding the incidence of specific diseases are available. This study aimed to identify the diseases that occur frequently in this species by surveying the incidence of conditions in pet A. mexicanum specimens brought to a veterinary hospital. The sample comprised 97 pet A. mexicanum individuals brought to the authors' hospital during the 82-month period, i.e., from January 2008 to October 2014. In total, 116 diseases were identified. The most common disease was hydrocoelom (32 cases; 27.5% of all cases). Elucidating the pathogenesis of hydrocoelom, which has a high prevalence rate, is vital to maintaining the long-term health of A. mexicanum pets.

  18. Lineage tracing of genome-edited alleles reveals high fidelity axolotl limb regeneration.

    Science.gov (United States)

    Flowers, Grant Parker; Sanor, Lucas D; Crews, Craig M

    2017-09-16

    Salamanders are unparalleled among tetrapods in their ability to regenerate many structures, including entire limbs, and the study of this ability may provide insights into human regenerative therapies. The complex structure of the limb poses challenges to the investigation of the cellular and molecular basis of its regeneration. Using CRISPR/Cas, we genetically labelled unique cell lineages within the developing axolotl embryo and tracked the frequency of each lineage within amputated and fully regenerated limbs. This allowed us, for the first time, to assess the contributions of multiple low frequency cell lineages to the regenerating limb at once. Our comparisons reveal that regenerated limbs are high fidelity replicas of the originals even after repeated amputations.

  19. Proliferation zones in the axolotl brain and regeneration of the telencephalon

    Directory of Open Access Journals (Sweden)

    Maden Malcolm

    2013-01-01

    Full Text Available Abstract Background Although the brains of lower vertebrates are known to exhibit somewhat limited regeneration after incisional or stab wounds, the Urodele brain exhibits extensive regeneration after massive tissue removal. Discovering whether and how neural progenitor cells that reside in the ventricular zones of Urodeles proliferate to mediate tissue repair in response to injury may produce novel leads for regenerative strategies. Here we show that endogenous neural progenitor cells resident to the ventricular zone of Urodeles spontaneously proliferate, producing progeny that migrate throughout the telencephalon before terminally differentiating into neurons. These progenitor cells appear to be responsible for telencephalon regeneration after tissue removal and their activity may be up-regulated by injury through an olfactory cue. Results There is extensive proliferation of endogenous neural progenitor cells throughout the ventricular zone of the adult axolotl brain. The highest levels are observed in the telencephalon, especially the dorsolateral aspect, and cerebellum. Lower levels are observed in the mesencephalon and rhombencephalon. New cells produced in the ventricular zone migrate laterally, dorsally and ventrally into the surrounding neuronal layer. After migrating from the ventricular zone, the new cells primarily express markers of neuronal differentiative fates. Large-scale telencephalic tissue removal stimulates progenitor cell proliferation in the ventricular zone of the damaged region, followed by proliferation in the tissue that surrounds the healing edges of the wound until the telencephalon has completed regeneration. The proliferative stimulus appears to reside in the olfactory system, because telencephalic regeneration does not occur in the brains of olfactory bulbectomized animals in which the damaged neural tissue simply heals over. Conclusion There is a continual generation of neuronal cells from neural progenitor cells

  20. Environmental assessment and finding of no significant impact: Hungry Horse--Columbia Falls line rebuild and relocation project

    International Nuclear Information System (INIS)

    1993-09-01

    Bonneville Power Administration (BPA) has identified a need to rebuild the Hungry Horse-Columbia Falls 115,000-volt (115-kV) transmission line to 230-kV. This line supplies power to customers in the area of Columbia Falls, Montana, and integrates generation at the US Bureau of Reclamation's (USBR) Hungry Horse Dam into BPA's transmission grid. There are several problems with the existing system. The Hungry Horse-Columbia Falls 1 15-kV line is 45 years old and requires excessive maintenance. The USBR has decided to replace their aging 115-kV transformers at the dam with 230-kV transformers, which also would increase their operational flexibility. With the small conductor size and voltage of the line presently being used, significant amounts of energy are lost as the power moves across the line. Transformer failure at Hungry Horse Dam has led to joint planning between BPA and the USBR. (USBR and the US Forest Service are cooperating agencies on the proposed project.) The proposal to eliminate the 115-kV equipment and convert to 230-kV operation was the least costly of the options studied. By rebuilding the line, maintenance costs (and time required for outages) would be reduced. The increased generation at the USBR dam would be safely and consistently transmitted over the improved system, and less energy would be lost from the line, a cost and energy savings

  1. Metamorfosis: La animalidad y el mito en La Metamorfosis de Kafka y Axolotl de Cortázar

    Directory of Open Access Journals (Sweden)

    Catalina Villalobos Díaz

    2017-07-01

    Full Text Available El presente artículo propone una lectura de la animalidad, principalmente de la metamorfosis, por medio de dos relatos de dos grandes escritores de la literatura: Axolotl, de Julio Cortázar, y La Metamorfosis, de Franz Kafka. A través de estos textos, se plantea un análisis con respecto a lo que representa una transformación y el mito tras la metamorfosis como tal.

  2. The discrete hungry Lotka Volterra system and a new algorithm for computing matrix eigenvalues

    Science.gov (United States)

    Fukuda, Akiko; Ishiwata, Emiko; Iwasaki, Masashi; Nakamura, Yoshimasa

    2009-01-01

    The discrete hungry Lotka-Volterra (dhLV) system is a generalization of the discrete Lotka-Volterra (dLV) system which stands for a prey-predator model in mathematical biology. In this paper, we show that (1) some invariants exist which are expressed by dhLV variables and are independent from the discrete time and (2) a dhLV variable converges to some positive constant or zero as the discrete time becomes sufficiently large. Some characteristic polynomial is then factorized with the help of the dhLV system. The asymptotic behaviour of the dhLV system enables us to design an algorithm for computing complex eigenvalues of a certain band matrix.

  3. The discrete hungry Lotka–Volterra system and a new algorithm for computing matrix eigenvalues

    International Nuclear Information System (INIS)

    Fukuda, Akiko; Ishiwata, Emiko; Iwasaki, Masashi; Nakamura, Yoshimasa

    2009-01-01

    The discrete hungry Lotka–Volterra (dhLV) system is a generalization of the discrete Lotka–Volterra (dLV) system which stands for a prey–predator model in mathematical biology. In this paper, we show that (1) some invariants exist which are expressed by dhLV variables and are independent from the discrete time and (2) a dhLV variable converges to some positive constant or zero as the discrete time becomes sufficiently large. Some characteristic polynomial is then factorized with the help of the dhLV system. The asymptotic behaviour of the dhLV system enables us to design an algorithm for computing complex eigenvalues of a certain band matrix

  4. The Center for Regenerative Biology and Medicine at Mount Desert Island Biological Laboratory

    Science.gov (United States)

    2015-08-01

    TERMS limb regeneration Positional Memory Code Axolotl microRNAs Zebrafish Polypterus 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18...injury induced regeneration of limbs/appendage tissues in Ambystoma ( axolotl ) and Polypterus animals. The defining feature of limb/appendage...downregulated in UPREGULATED DOWNREGULATED Figure 1: Venn diagram of UniProt protein sequence IDs among Axolotl and Polypterus contigs that

  5. BMP-2 functions independently of SHH signaling and triggers cell condensation and apoptosis in regenerating axolotl limbs

    Directory of Open Access Journals (Sweden)

    Finnson Kenneth

    2010-02-01

    Full Text Available Abstract Background Axolotls have the unique ability, among vertebrates, to perfectly regenerate complex body parts, such as limbs, after amputation. In addition, axolotls pattern developing and regenerating autopods from the anterior to posterior axis instead of posterior to anterior like all tetrapods studied to date. Sonic hedgehog is important in establishing this anterior-posterior axis of limbs in all tetrapods including axolotls. Interestingly, its expression is conserved (to the posterior side of limb buds and blastemas in axolotl limbs as in other tetrapods. It has been suggested that BMP-2 may be the secondary mediator of sonic hedgehog, although there is mounting evidence to the contrary in mice. Since BMP-2 expression is on the anterior portion of developing and regenerating limbs prior to digit patterning, opposite to the expression of sonic hedgehog, we examined whether BMP-2 expression was dependent on sonic hedgehog signaling and whether it affects patterning of the autopod during regeneration. Results The expression of BMP-2 and SOX-9 in developing and regenerating axolotl limbs corresponded to the first digits forming in the anterior portion of the autopods. The inhibition of sonic hedgehog signaling with cyclopamine caused hypomorphic limbs (during development and regeneration but did not affect the expression of BMP-2 and SOX-9. Overexpression of BMP-2 in regenerating limbs caused a loss of digits. Overexpression of Noggin (BMP inhibitor in regenerating limbs also resulted in a loss of digits. Histological analysis indicated that the loss due to BMP-2 overexpression was the result of increased cell condensation and apoptosis while the loss caused by Noggin was due to a decrease in cell division. Conclusion The expression of BMP-2 and its target SOX-9 was independent of sonic hedgehog signaling in developing and regenerating limbs. Their expression correlated with chondrogenesis and the appearance of skeletal elements has

  6. Effects of the Operation of Hungry Horse Dam on the Kokanee Fishery in the Flathead River System, 1983 Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Fraley, John J.

    1983-11-01

    This study was undertaken to assess the effects of the operation of Hungry Horse Dam on the kokanee fishery in the Flathead River system. This annual report covers the 1982-1983 field season concerning the effects of Hungry Horse operations on kokanee abundance, migration, spawning, egg incubation and fry emergence in the Flathead River system. This report also addresses the expected recovery of the mainstem kokanee population under the flow regime recommended by the Department of Fish, Wildlife and Parks in 1982.

  7. The testicular sperm ducts and genital kidney of male Ambystoma maculatum (Amphibia, Urodela, Ambystomatidae).

    Science.gov (United States)

    Siegel, Dustin S; Aldridge, Robert D; Rheubert, Justin L; Gribbins, Kevin M; Sever, David M; Trauth, Stanley E

    2013-03-01

    The ducts associated with sperm transport from the testicular lobules to the Wolffian ducts in Ambystoma maculatum were examined with transmission electron microscopy. Based on the ultrastructure and historical precedence, new terminology for this network of ducts is proposed that better represents primary hypotheses of homology. Furthermore, the terminology proposed better characterizes the distinct regions of the sperm transport ducts in salamanders based on anatomy and should, therefore, lead to more accurate comparisons in the future. While developing the above ontology, we also tested the hypothesis that nephrons from the genital kidney are modified from those of the pelvic kidney due to the fact that the former nephrons function in sperm transport. Our ultrastructural analysis of the genital kidney supports this hypothesis, as the basal plasma membrane of distinct functional regions of the nephron (proximal convoluted tubule, distal convoluted tubule, and collecting tubule) appear less folded (indicating decreased surface area and reduced reabsorption efficiency) and the proximal convoluted tubule possesses ciliated epithelial cells along its entire length. Furthermore, visible luminal filtrate is absent from the nephrons of the genital kidney throughout their entire length. Thus, it appears that the nephrons of the genital kidney have reduced reabsorptive capacity and ciliated cells of the proximal convoluted tubule may increase the movement of immature sperm through the sperm transport ducts or aid in the mixing of seminal fluids within the ducts. Copyright © 2012 Wiley Periodicals, Inc.

  8. Comparative transcriptional profiling of the axolotl limb identifies a tripartite regeneration-specific gene program.

    Directory of Open Access Journals (Sweden)

    Dunja Knapp

    Full Text Available Understanding how the limb blastema is established after the initial wound healing response is an important aspect of regeneration research. Here we performed parallel expression profile time courses of healing lateral wounds versus amputated limbs in axolotl. This comparison between wound healing and regeneration allowed us to identify amputation-specific genes. By clustering the expression profiles of these samples, we could detect three distinguishable phases of gene expression - early wound healing followed by a transition-phase leading to establishment of the limb development program, which correspond to the three phases of limb regeneration that had been defined by morphological criteria. By focusing on the transition-phase, we identified 93 strictly amputation-associated genes many of which are implicated in oxidative-stress response, chromatin modification, epithelial development or limb development. We further classified the genes based on whether they were or were not significantly expressed in the developing limb bud. The specific localization of 53 selected candidates within the blastema was investigated by in situ hybridization. In summary, we identified a set of genes that are expressed specifically during regeneration and are therefore, likely candidates for the regulation of blastema formation.

  9. DNA Methylation Dynamics Regulate the Formation of a Regenerative Wound Epithelium during Axolotl Limb Regeneration.

    Directory of Open Access Journals (Sweden)

    Cristian Aguilar

    Full Text Available The formation of a blastema during regeneration of an axolotl limb involves important changes in the behavior and function of cells at the site of injury. One of the earliest events is the formation of the wound epithelium and subsequently the apical epidermal cap, which involves in vivo dedifferentiation that is controlled by signaling from the nerve. We have investigated the role of epigenetic modifications to the genome as a possible mechanism for regulating changes in gene expression patterns of keratinocytes of the wound and blastema epithelium that are involved in regeneration. We report a modulation of the expression DNMT3a, a de novo DNA methyltransferase, within the first 72 hours post injury that is dependent on nerve signaling. Treatment of skin wounds on the upper forelimb with decitabine, a DNA methyltransferase inhibitor, induced changes in gene expression and cellular behavior associated with a regenerative response. Furthermore, decitabine-treated wounds were able to participate in regeneration while untreated wounds inhibited a regenerative response. Elucidation of the specific epigenetic modifications that mediate cellular dedifferentiation likely will lead to insights for initiating a regenerative response in organisms that lack this ability.

  10. Flavour-flavour learning occurs automatically and only in hungry participants.

    Science.gov (United States)

    Brunstrom, Jeffrey M; Fletcher, Hollie Z

    2008-01-28

    A novel flavour may become liked if it is presented repeatedly and in combination with a second flavour that is already liked. Conceptually, this 'flavour-flavour learning' is important, because it can account for many of our everyday food and flavour preferences. However, relatively little is known about the underlying process because learning paradigms have lacked reliability. Based on previous research we explored whether learning is determined by three variables; i) hunger state, ii) demand and contingency awareness, and iii) dietary restraint. Participants (male n=15/female n=15) consumed three different and novel-tasting fruit teas. One of the teas had a non-caloric sweetener added (CS+) and two were unsweetened (CS-). Before and after this training the participants ranked their preference for unsweetened versions of the three teas. We found that the training increased preference for the CS+ relative to the CS- teas. However, this effect was only found in hungry participants. We also found little evidence that learning was related to whether the participants could identify (recognition test) the specific tea that had been sweetened during training, suggesting that the underlying process is automatic and it operates outside conscious awareness. Learning was not predicted by dietary restraint (measured using the DEBQ-R scale). Together, these findings provide further evidence for a linkage between flavour-flavour learning and flavour-nutrient learning.

  11. At the Table with Hungry Ghosts: Intimate Borderwork in Mexico City

    Directory of Open Access Journals (Sweden)

    Jean Duruz

    2011-09-01

    Full Text Available This article focuses on the project of sustaining cultural diversity within global cities’ intimate spaces. Specifically, it sketches the culinary histories of an Anglo-Australian woman (who, in 1968, settled permanently in Mexico and her male partner (who grew up in Mexico; his mother Mexican, his father Cantonese. Drawing on the tools of ‘borderwork’ (Hodge and O’Carroll, the argument positions culturally diverse landscapes of ‘Sydney’, ‘China’ and ‘Mexico City’ as distinct yet overlapping geographies. Meanwhile, analysis of curious moments in the couple’s intersecting histories contributes much fluidity to this cartography. In the process, a company of hungry ghosts appears at the dinner table – ghosts of diversity, diaspora and cosmopolitanism; nostalgia and memory; gender and ethnicity; home and belonging. The article concludes that even when borderwork is conducted amiably behind closed doors, it relies on contradictions for cultural sustenance. At the same time, its tensions resonate with possibilities for creative practice.

  12. Libby/Hungry Horse Dams Wildlife Mitigation Habitat Protection : Interim Report.

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Marilyn

    1991-04-01

    The Columbia River Basin Fish and Wildlife Program identified mitigation goals for Hungry Horse and Libby dams (1987). Specific programs goals included: (1) protect and/or enhance 4565 acres of wetland habitat in the Flathead Valley; (2) protect 2462 acres of prairie habitat within the vicinity of the Tobacco Plains Columbian sharp-tailed grouse; (3) protect 8590 acres riparian habitat in northwest Montana for grizzly and black bears; and (4) protect 11,500 acres of terrestrial furbearer habitat through cooperative agreements with state and federal agencies and private landowners. The purpose of this project is to continue to develop and obtain information necessary to evaluate and implement specific wildlife habitat protection actions in northwestern Montana. This report summarizes project work completed between May 1, 1990, and December 31, 1990. There were three primary project objectives during this time: obtain specific information necessary to develop the mitigation program for Columbian sharp-tailed grouse; continue efforts necessary to develop, refine, and coordinate the mitigation programs for waterfowl/wetlands and grizzly/black bears; determine the opportunity and appropriate strategies for protecting terrestrial furbearer habitat by lease or management agreements on state, federal and private lands. 19 refs., 1 tab.

  13. Role of thyroid hormones in the normal and glucocorticosteroid hormone-induced evolution of carbamoyl-phosphate synthase (ammonia) activity in axolotl liver

    NARCIS (Netherlands)

    Lamers, W. H.; Vink, C.; Charles, R.

    1978-01-01

    1. In axolotl liver, the activity of carbamoyl-phosphate synthase (ammonia), expressed per mg liver protein, decreases to a minimum at 5 months of age, then increases to a maximum at 8 months of age which is followed by a decrease again. The initial decrease between 3 and 5 months of age appears to

  14. FGF and BMP derived from dorsal root ganglia regulate blastema induction in limb regeneration in Ambystoma mexicanum.

    Science.gov (United States)

    Satoh, Akira; Makanae, Aki; Nishimoto, Yurie; Mitogawa, Kazumasa

    2016-09-01

    Urodele amphibians have a remarkable organ regeneration ability that is regulated by neural inputs. The identification of these neural inputs has been a challenge. Recently, Fibroblast growth factor (Fgf) and Bone morphogenic protein (Bmp) were shown to substitute for nerve functions in limb and tail regeneration in urodele amphibians. However, direct evidence of Fgf and Bmp being secreted from nerve endings and regulating regeneration has not yet been shown. Thus, it remained uncertain whether they were the nerve factors responsible for successful limb regeneration. To gather experimental evidence, the technical difficulties involved in the usage of axolotls had to be overcome. We achieved this by modifying the electroporation method. When Fgf8-AcGFP or Bmp7-AcGFP was electroporated into the axolotl dorsal root ganglia (DRG), GFP signals were detectable in the regenerating limb region. This suggested that Fgf8 and Bmp7 synthesized in neural cells in the DRG were delivered to the limbs through the long axons. Further knockdown experiments with double-stranded RNA interference resulted in impaired limb regeneration ability. These results strongly suggest that Fgf and Bmp are the major neural inputs that control the organ regeneration ability. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Tiger salamanders' (Ambystoma tigrinum) response learning and usage of visual cues.

    Science.gov (United States)

    Kundey, Shannon M A; Millar, Roberto; McPherson, Justin; Gonzalez, Maya; Fitz, Aleyna; Allen, Chadbourne

    2016-05-01

    We explored tiger salamanders' (Ambystoma tigrinum) learning to execute a response within a maze as proximal visual cue conditions varied. In Experiment 1, salamanders learned to turn consistently in a T-maze for reinforcement before the maze was rotated. All learned the initial task and executed the trained turn during test, suggesting that they learned to demonstrate the reinforced response during training and continued to perform it during test. In a second experiment utilizing a similar procedure, two visual cues were placed consistently at the maze junction. Salamanders were reinforced for turning towards one cue. Cue placement was reversed during test. All learned the initial task, but executed the trained turn rather than turning towards the visual cue during test, evidencing response learning. In Experiment 3, we investigated whether a compound visual cue could control salamanders' behaviour when it was the only cue predictive of reinforcement in a cross-maze by varying start position and cue placement. All learned to turn in the direction indicated by the compound visual cue, indicating that visual cues can come to control their behaviour. Following training, testing revealed that salamanders attended to stimuli foreground over background features. Overall, these results suggest that salamanders learn to execute responses over learning to use visual cues but can use visual cues if required. Our success with this paradigm offers the potential in future studies to explore salamanders' cognition further, as well as to shed light on how features of the tiger salamanders' life history (e.g. hibernation and metamorphosis) impact cognition.

  16. Mechanics of lung ventilation in a post-metamorphic salamander, Ambystoma Tigrinum.

    Science.gov (United States)

    Simons, R S; Bennett, W O; Brainerd, E L

    2000-03-01

    The mechanics of lung ventilation in frogs and aquatic salamanders has been well characterized, whereas lung ventilation in terrestrial-phase (post-metamorphic) salamanders has received little attention. We used electromyography (EMG), X-ray videography, standard videography and buccal and body cavity pressure measurements to characterize the ventilation mechanics of adult (post-metamorphic) tiger salamanders (Ambystoma tigrinum). Three results emerged: (i) under terrestrial conditions or when floating at the surface of the water, adult A. tigrinum breathed through their nares using a two-stroke buccal pump; (ii) in addition to this narial two-stroke pump, adult tiger salamanders also gulped air in through their mouths using a modified two-stroke buccal pump when in an aquatic environment; and (iii) exhalation in adult tiger salamanders is active during aquatic gulping breaths, whereas exhalation appears to be passive during terrestrial breathing at rest. Active exhalation in aquatic breaths is indicated by an increase in body cavity pressure during exhalation and associated EMG activity in the lateral hypaxial musculature, particularly the M. transversus abdominis. In terrestrial breathing, no EMG activity in the lateral hypaxial muscles is generally present, and body cavity pressure decreases during exhalation. In aquatic breaths, tidal volume is larger than in terrestrial breaths, and breathing frequency is much lower (approximately 1 breath 10 min(-)(1 )versus 4-6 breaths min(-)(1)). The use of hypaxial muscles to power active exhalation in the aquatic environment may result from the need for more complete exhalation and larger tidal volumes when breathing infrequently. This hypothesis is supported by previous findings that terrestrial frogs ventilate their lungs with small tidal volumes and exhale passively, whereas aquatic frogs and salamanders use large tidal volumes and and exhale actively.

  17. Diet of larval Ambystoma rivulare (Caudata: Ambystomatidae, a threatened salamander from the Volcán Nevado de Toluca, Mexico

    Directory of Open Access Journals (Sweden)

    Julio A. Lemos-Espinal

    2015-06-01

    Full Text Available Several species of salamander in the genus Ambystoma occur in the mountains surrounding Mexico City and are considered at risk of extinction. However, little is known about their ecology and natural history. The Toluca Stream Siredon (Ambystoma rivulare is classified as “Data Deficient” by the IUCN, and considered “Threatened” under Mexican law. From October 2013 to September 2014, we examined the diet of larval A. rivulare from a stream on the Volcán Nevado de Toluca in Mexico to provide insight into the suitability of the habitat to support this population of salamanders. Ostracods accounted for approximately 90% of all prey items consumed by larval A. rivulare. The number of ostracods found in stomachs increased with individual body size, but the proportion of ostracods in stomachs did not vary with body size. Nematodes were observed in approximately one third of the stomachs we examined. The diversity of prey in the diet of A. rivulare in the stream we studied is low and dominated by a single prey taxon, ostracods. Our results suggest that if environmental conditions in the stream change such that ostracods are negatively affected then the long-term persistence of this population of A. rivulare might be in jeopardy.

  18. Ion channel signaling influences cellular proliferation and phagocyte activity during axolotl tail regeneration.

    Science.gov (United States)

    Franklin, Brandon M; Voss, S Randal; Osborn, Jeffrey L

    2017-08-01

    Little is known about the potential for ion channels to regulate cellular behaviors during tissue regeneration. Here, we utilized an amphibian tail regeneration assay coupled with a chemical genetic screen to identify ion channel antagonists that altered critical cellular processes during regeneration. Inhibition of multiple ion channels either partially (anoctamin1/Tmem16a, anoctamin2/Tmem16b, K V 2.1, K V 2.2, L-type Ca V channels and H/K ATPases) or completely (GlyR, GABA A R, K V 1.5 and SERCA pumps) inhibited tail regeneration. Partial inhibition of tail regeneration by blocking the calcium activated chloride channels, anoctamin1&2, was associated with a reduction of cellular proliferation in tail muscle and mesenchymal regions. Inhibition of anoctamin 1/2 also altered the post-amputation transcriptional response of p44/42 MAPK signaling pathway genes, including decreased expression of erk1/erk2. We also found that complete inhibition via voltage gated K + channel blockade was associated with diminished phagocyte recruitment to the amputation site. The identification of H + pumps as required for axolotl tail regeneration supports findings in Xenopus and Planaria models, and more generally, the conservation of ion channels as regulators of tissue regeneration. This study provides a preliminary framework for an in-depth investigation of the mechanistic role of ion channels and their potential involvement in regulating cellular proliferation and other processes essential to wound healing, appendage regeneration, and tissue repair. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Wildlife Loss Estimates and Summary of Previous Mitigation Related to Hydroelectric Projects in Montana, Volume Three, Hungry Horse Project.

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Daniel

    1984-10-01

    This assessment addresses the impacts to the wildlife populations and wildlife habitats due to the Hungry Horse Dam project on the South Fork of the Flathead River and previous mitigation of theses losses. In order to develop and focus mitigation efforts, it was first necessary to estimate wildlife and wildlife hatitat losses attributable to the construction and operation of the project. The purpose of this report was to document the best available information concerning the degree of impacts to target wildlife species. Indirect benefits to wildlife species not listed will be identified during the development of alternative mitigation measures. Wildlife species incurring positive impacts attributable to the project were identified.

  20. The pelvic kidney of male Ambystoma maculatum (Amphibia, urodela, ambystomatidae) with special reference to the sexual collecting ducts.

    Science.gov (United States)

    Siegel, Dustin S; Sever, David M; Aldridge, Robert D

    2010-12-01

    This study details the gross and microscopic anatomy of the pelvic kidney in male Ambystoma maculatum. The nephron of male Ambystoma maculatum is divided into six distinct regions leading sequentially away from a renal corpuscle: (1) neck segment, which communicates with the coelomic cavity via a ventrally positioned pleuroperitoneal funnel, (2) proximal tubule, (3) intermediate segment, (4) distal tubule, (5) collecting tubule, and (6) collecting duct. The proximal tubule is divided into a vacuolated proximal region and a distal lysosomic region. The basal plasma membrane is modified into intertwining microvillus lamellae. The epithelium of the distal tubule varies little along its length and is demarcated by columns of mitochondria with their long axes oriented perpendicular to the basal lamina. The distal tubule possesses highly interdigitating microvillus lamellae from the lateral membranes and pronounced foot processes of the basal membrane that are not intertwined, but perpendicular to the basal lamina. The collecting tubule is lined by an epithelium with dark and light cells. Light cells are similar to those observed in the distal tuble except with less mitochondria and microvillus lamellae of the lateral and basal plasma membrane. Dark cells possess dark euchromatic nuclei and are filled with numerous small mitochondria. The epithelium of the neck segment, pleuroperitoneal funnel, and intermediate segment is composed entirely of ciliated cells with cilia protruding from only the central portion of the apical plasma membrane. The collecting duct is lined by a highly secretory epithelium that produces numerous membrane bound granules that stain positively for neutral carbohydrates and proteins. Apically positioned ciliated cells are intercalated between secretory cells. The collecting ducts anastomose caudally and unite with the Wolffian duct via a common collecting duct. The Wolffian duct is secretory, but not to the extent of the collecting duct

  1. Hungry Horse Dam fisheries mitigation program: Fish passage and habitat improvement in the Upper Flathead River basin

    International Nuclear Information System (INIS)

    Knotek, W.L.; Deleray, M.; Marotz, B.

    1997-08-01

    In the past 50 years, dramatic changes have occurred in the Flathead Lake and River system. Degradation of fishery resources has been evident, in part due to deterioration of aquatic habitat and introduction of non-endemic fish and invertebrate species. Habitat loss has been attributed to many factors including the construction and operation of Hungry Horse Dam, unsound land use practices, urban development, and other anthropogenic and natural disturbances. Fish migration has also been limited by barriers such as dams and impassible culverts. Cumulatively, these factors have contributed to declines in the distribution and abundance of native fish populations. Recovery of fish populations requires that a watershed approach be developed that incorporates long-term aquatic habitat needs and promotes sound land use practices and cooperation among natural resource management agencies. In this document, the authors (1) describe completed and ongoing habitat improvement and fish passage activities under the Hungry Horse Fisheries Mitigation Program, (2) describe recently identified projects that are in the planning stage, and (3) develop a framework for identifying prioritizing, implementing, and evaluating future fish habitat improvement and passage projects

  2. Atypical Parathyroid Adenoma Complicated with Protracted Hungry Bone Syndrome after Surgery: A Case Report and Literature Review

    Directory of Open Access Journals (Sweden)

    Óscar Alfredo Juárez-León

    2015-01-01

    Full Text Available Hungry Bone Syndrome refers to the severe and prolonged hypocalcemia and hypophosphatemia, following parathyroidectomy in patients with hyperparathyroidism. We present the case of an eighteen-year-old woman with a four-year history of hyporexia, polydipsia, weight loss, growth retardation, and poor academic performance. The diagnostic work-up demonstrated primary hyperparathyroidism with hypercalcemia of 13.36 mg/dL, a PTH level of 2551 pg/mL, bone brown tumors, and microcalcifications within pancreas and kidneys. Neck ultrasonography revealed a parathyroid adenoma of 33 × 14 × 14 mm, also identified on 99Tc-sestamibi scan. Bone densitometry showed decreased Z-Score values (total lumbar Z-Score of −4.2. A right hemithyroidectomy and right lower parathyroidectomy were performed. Pathological examination showed an atypical parathyroid adenoma, of 3.8 g of weight and 2.8 cm in diameter. After surgery she developed hypocalcemia with tetany and QTc interval prolongation. The patient required 3 months of oral and intravenous calcium supplementation due to Hungry Bone Syndrome (HBS. After 42 months, she is still under oral calcium. Usually HBS lasts less than 12 months. Therefore we propose the term “Protracted HBS” in patients with particularly long recovery of 1 year. We present a literature review of the diagnosis, pathophysiology, and treatment of HBS.

  3. Limb regeneration from X-irradiated tails of Ambystoma mexicanum following transplantation of flank skin from region adjacent to hindlimb

    International Nuclear Information System (INIS)

    Hofmann, D.K.; Kleinebeckel, D.; Luther, W.

    1978-01-01

    In the experiments performed by W. Luther on young Ambystoma mexicanum, tails of host animals were irradiated with 2000 r. Afterwards a skin cuff was removed from the mid-tail region. From non-irradiated donor animals, square pieces of skin dorsally adjacent to both hindlimbs were grafted (either 90 0 -rotated or unrotated) to both sides of the denuded area of the irradiated host tail. After 3 weeks the tails were amputated across the skin transplants, and the structures which had regenerated from the distal portions of the tails were fixed 6-16 weeks later. Morhological and histological investigation revealed that 4 out of 12 regenerates from rotated grafts showed clear limb characteristics. (orig./AJ) [de

  4. Effects of atrazine on egg masses of the yellow-spotted salamander (Ambystoma maculatum) and its endosymbiotic alga (Oophila amblystomatis)

    International Nuclear Information System (INIS)

    Baxter, Leilan; Brain, Richard A.; Hosmer, Alan J.; Nema, Mohini; Müller, Kirsten M.; Solomon, Keith R.; Hanson, Mark L.

    2015-01-01

    Embryonic growth of the yellow-spotted salamander (Ambystoma maculatum) is enhanced by the presence of the green alga Oophila amblystomatis, in the egg capsule. To further assess potential impacts of herbicides on this relationship, A. maculatum egg masses were exposed to atrazine (0–338 μg/L) until hatching (up to 66 days). Exposure to atrazine reduced PSII yield of the symbiotic algae in a concentration-dependent manner, but did not significantly affect visible algal growth or any metrics associated with salamander development. Algal cells were also cultured in the laboratory for toxicity testing. In the 96-h growth inhibition test (0–680 μg/L), ECx values were generally greater than those reported for standard algal test species. Complete recovery of growth rates occurred within 96-h of transferring cells to untreated media. Overall, development of A. maculatum embryos was not affected by exposure to atrazine at concentrations and durations exceeding those found in the environment. - Highlights: • The yellow-spotted salamander produces eggs that are colonized by a symbiotic green alga. • We tested the sensitivity of this system to the herbicide atrazine. • Embryo development was not significantly affected by exposure at up to 300 μg/L. • The alga was isolated and 96-h growth tests were performed in the laboratory. • EC50s for Oophila sp. were >100 μg/L. - Development of Ambystoma maculatum embryos in egg masses was not impacted by exposure to atrazine at concentrations and durations exceeding those commonly found in the environment.

  5. Model Development to Establish Integrated Operational Rule Curves for Hungry Horse and Libby Reservoirs - Montana, 1996 Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Marotz, Brian; Althen, Craig; Gustafson, Daniel

    1996-01-01

    Hungry Horse and Libby dams have profoundly affected the aquatic ecosystems in two major tributaries of the Columbia River by altering habitat and water quality, and by imposing barriers to fish migration. In 1980, the U.S. Congress passed the Pacific Northwest Electric Power Planning and Conservation Act, designed in part to balance hydropower development with other natural resources in the Columbia System. The Act formed the Northwest Power Planning Council (Council) who developed a program to protect, mitigate and enhance fish and wildlife on the Columbia River and its tributaries. Pursuant to the Council`s Fish and Wildlife Program for the Columbia River System (1987), we constructed computer models to simulate the trophic dynamics of the reservoir biota as related to dam operation. Results were used to develop strategies to minimize impacts and enhance the reservoir and riverine fisheries, following program measures 903(a)(1-4) and 903(b)(1-5). Two FORTRAN simulation models were developed for Hungry Horse and Libby reservoirs located in northwestern Montana. The models were designed to generate accurate, short-term predictions specific to two reservoirs and are not directly applicable to other waters. The modeling strategy, however, is portable to other reservoir systems where sufficient data are available. Reservoir operation guidelines were developed to balance fisheries concerns in the headwaters with anadromous species recovery actions in the lower Columbia (Biological Rule Curves). These BRCs were then integrated with power production and flood control to reduce the economic impact of basin-wide fisheries recovery actions. These Integrated Rule Curves (IRCs) were developed simultaneously in the Columbia Basin System Operation Review (SOR), the Council`s phase IV amendment process and recovery actions associated with endangered Columbia Basin fish species.

  6. Visualisation of axolotl blastema cells and pig endothelial progenitor cells using very small super paramagnetic iron oxide particles in MRI: A technique with applications for non invasive visualisation of regenerative processes

    DEFF Research Database (Denmark)

    Lauridsen, Henrik; Kjær, N.B.; Bek, Maria

    oxide particles (VSOP) in animal cells enable non invasive cell tracking using magnetic resonance imaging (MRI) and can prove useful, when visualising regenerative processes. This study examines the possibility of labelling limited numbers of axolotl blastema cells (aBC) and pig endothelial progenitor...... implanted in live axolotl tail and dead porcine heart, respectively. Cellular iron uptake was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Results: T2*-weighted 2D gradient-echo sequences on samples of 10˄5 cells yielded at significant linear correlations between...

  7. Intracellular Signalling in Retinal Ischemia

    Science.gov (United States)

    1990-07-01

    spatial buffering capacity of the Miller cells of axolotl retina indicated that gap junctional coupling can increase the capacity of the Muller cell to...1974. 27 33. Mobbs P, Brew H, and Atwell D: A quantitative analysis of glial cell coupling in the retina of the axolotl (Ambystoma mexicanum). Brain

  8. The effects of simulated solar UVB radiation on early developmental stages of the Northwestern Salamander (Ambystoma gracile) from three lakes

    Science.gov (United States)

    Calfee, Robin D.; Little, Edward E.; Pearl, Christopher A.; Hoffman, Robert L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290–320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66% of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation.

  9. Liver histological changes and lipid peroxidation in the amphibian Ambystoma mexicanum induced by sediment elutriates from the Lake Xochimilco.

    Science.gov (United States)

    Ortiz-Ordoñez, Esperanza; López-López, Eugenia; Sedeño-Díaz, Jacinto Elías; Uría, Esther; Morales, Ignacio Andrés; Pérez, María Estela; Shibayama, Mineko

    2016-08-01

    Lacustrine sediments accumulate pollutants that input from the lake watershed and can be released to the water column by sediment resuspension; thus, pollutants can change their bioavailability and exert adverse effects to aquatic biota. Shallow-urban lakes are particularly susceptible to receive pollutants from urban discharges and sediment resuspension. Lake Xochimilco, in Mexico City, an urban-shallow lake, faces multiple problems: urban sprawl, overexploitation of aquifers, drying of springs, discharge of wastewater from treatment plants, and sediment resuspension. The aquatic biota living in this ecosystem is continuously exposed to the release of pollutants from the sediments. We assessed the risk that pollutants released from sediments from Lake Xochimilco, Touristic (TZ) and Agriculture zone (AZ), can exert on a native amphibian species of the lake (Ambystoma mexicanum) through exposure bioassays to sediment elutriates. We evaluate alterations in the amphibian by three approaches: biochemical (level of lipid peroxidation, LPO), cellular (ultrastructure) and the liver histology of A. mexicanum and we compare them with a batch control. Additionally, we assessed heavy metals (Pb, Cd and Hg) in elutriates. Elutriates from TZ showed the highest concentrations of the metals assessed. Organisms exposed to sediment elutriates from either study sites showed higher LPO values than control organisms (pXochimilco. Copyright © 2016. Published by Elsevier B.V.

  10. The effects of food level and conspecific density on biting and cannibalism in larval long-toed salamanders, Ambystoma macrodactylum.

    Science.gov (United States)

    Wildy, Erica L; Chivers, Douglas P; Kiesecker, Joseph M; Blaustein, Andrew R

    2001-07-01

    Previous studies have examined abiotic and biotic factors that facilitate agonistic behavior. For larval amphibians, food availability and conspecific density have been suggested as important factors influencing intraspecific aggression and cannibalism. In this study, we examined the separate and combined effects of food availability and density on the agonistic behavior and life history of larval long-toed salamanders, Ambystoma macrodactylum. We designed a 2×2 factorial experiment in which larvae were raised with either a high or low density of conspecifics and fed either a high or low level of food. For each treatment, we quantified the amount of group size variation, biting, and cannibalism occurring. Additionally, we examined survival to, time to and size at metamorphosis for all larvae. Results indicated that differences in both density and food level influenced all three life history traits measured. Moreover, differences in food level at which larvae were reared resulted in higher within-group size variation and heightened intraspecific biting while both density and food level contributed to increased cannibalism. We suggest that increased hunger levels and an uneven size structure promoted biting among larvae in the low food treatments. Moreover, these factors combined with a higher encounter rate with conspecifics in the high density treatments may have prompted larger individuals to seek an alternative food source in the form of smaller conspecifics.

  11. Food words distract the hungry: Evidence of involuntary semantic processing of task-irrelevant but biologically-relevant unexpected auditory words.

    Science.gov (United States)

    Parmentier, Fabrice B R; Pacheco-Unguetti, Antonia P; Valero, Sara

    2018-01-01

    Rare changes in a stream of otherwise repeated task-irrelevant sounds break through selective attention and disrupt performance in an unrelated visual task by triggering shifts of attention to and from the deviant sound (deviance distraction). Evidence indicates that the involuntary orientation of attention to unexpected sounds is followed by their semantic processing. However, past demonstrations relied on tasks in which the meaning of the deviant sounds overlapped with features of the primary task. Here we examine whether such processing is observed when no such overlap is present but sounds carry some relevance to the participants' biological need to eat when hungry. We report the results of an experiment in which hungry and satiated participants partook in a cross-modal oddball task in which they categorized visual digits (odd/even) while ignoring task-irrelevant sounds. On most trials the irrelevant sound was a sinewave tone (standard sound). On the remaining trials, deviant sounds consisted of spoken words related to food (food deviants) or control words (control deviants). Questionnaire data confirmed state (but not trait) differences between the two groups with respect to food craving, as well as a greater desire to eat the food corresponding to the food-related words in the hungry relative to the satiated participants. The results of the oddball task revealed that food deviants produced greater distraction (longer response times) than control deviants in hungry participants while the reverse effect was observed in satiated participants. This effect was observed in the first block of trials but disappeared thereafter, reflecting semantic saturation. Our results suggest that (1) the semantic content of deviant sounds is involuntarily processed even when sharing no feature with the primary task; and that (2) distraction by deviant sounds can be modulated by the participants' biological needs.

  12. Risk factors and clinical course of hungry bone syndrome after total parathyroidectomy in dialysis patients with secondary hyperparathyroidism.

    Science.gov (United States)

    Ho, Lo-Yi; Wong, Ping-Nam; Sin, Ho-Kwan; Wong, Yuk-Yi; Lo, Kwok-Chi; Chan, Shuk-Fan; Lo, Man-Wai; Lo, Kin-Yee; Mak, Siu-Ka; Wong, Andrew Kui-Man

    2017-01-10

    Hungry bone syndrome (HBS) is an important postoperative complication after parathyroidectomy for severe secondary hyperparathyroidism (SHPT). There is, however, little data in the literature on its detailed clinical course, and the associated risk factors remain controversial. We did a single-center retrospective study on 62 consecutive dialysis patients who underwent total parathyroidectomy for SHPT to examine the risk factors, clinical course and outcome. Data on demographic characteristics, perioperative laboratory parameters including serum calcium, phosphate, alkaline phosphatase (ALP) and parathyroid hormone (PTH), drug treatment for SHPT and operative details of parathyroidectomy were collected. Seventeen (27.4%) patients developed severe postoperative hypocalcemia with HBS. The serum calcium dropped progressively while serum ALP rose after operation until 2 weeks later when serum calcium reached the trough and serum ALP peaked. Serum phosphate also fell but stabilized between 4 and 14 days. The total postoperative calcium and vitamin D supplementation was significantly larger, and hospital stay was significantly longer in the group with HBS as compared with those without HBS. Young age, high body weight, high preoperative ALP level, and low preoperative calcium level independently predicted the development of HBS while preoperative PTH and use of cinacalcet or paricalcitol did not. HBS was common after total parathyroidectomy in patients with SHPT, and it is important to closely monitor the postoperative serum calcium, phosphate and ALP levels in the following 2 weeks, especially for those at risk. The implications of our findings on perioperative management are discussed.

  13. Effects of simulated solar UVB radiation on early developmental stages of the northwestern salamander (Ambystoma gracile) from three lakes

    Science.gov (United States)

    Calfee, R.D.; Little, E.E.; Pearl, C.A.; Hoffman, R.L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290-320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66 of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation. Copyright 2010 Society for the Study of Amphibians and Reptiles.

  14. CRISPR-Mediated Genomic Deletion of Sox2 in the Axolotl Shows a Requirement in Spinal Cord Neural Stem Cell Amplification during Tail Regeneration

    Directory of Open Access Journals (Sweden)

    Ji-Feng Fei

    2014-09-01

    Full Text Available The salamander is the only tetrapod that functionally regenerates all cell types of the limb and spinal cord (SC and thus represents an important regeneration model, but the lack of gene-knockout technology has limited molecular analysis. We compared transcriptional activator-like effector nucleases (TALENs and clustered regularly interspaced short palindromic repeats (CRISPRs in the knockout of three loci in the axolotl and find that CRISPRs show highly penetrant knockout with less toxic effects compared to TALENs. Deletion of Sox2 in up to 100% of cells yielded viable F0 larvae with normal SC organization and ependymoglial cell marker expression such as GFAP and ZO-1. However, upon tail amputation, neural stem cell proliferation was inhibited, resulting in spinal-cord-specific regeneration failure. In contrast, the mesodermal blastema formed normally. Sox3 expression during development, but not regeneration, most likely allowed embryonic survival and the regeneration-specific phenotype. This analysis represents the first tissue-specific regeneration phenotype from the genomic deletion of a gene in the axolotl.

  15. Morphology and evolutionary implications of the annual cycle of secretion and sperm storage in spermathecae of the salamander Ambystoma opacum (Amphibia: Ambystomatidae).

    Science.gov (United States)

    Sever, David M; Krenz, John D; Johnson, Kristin M; Rania, Lisa C

    1995-01-01

    Females of the marbled salamander, Ambystoma opacum, store sperm in exocrine glands called spermathecae in the roof of the cloaca. Eggs are fertilized by sperm released from the spermathecae during oviposition. Some sperm remain in the spermathecae following oviposition, but these sperm degenerate within a month and none persists more than 6 mo after oviposition. Thus, sperm storage between successive breeding seasons does not occur. Apical secretory vaculoes are abundant during the fall mating season and contain a substance that is alcian blue+ at pH 2.5. Production of secretory vacuoles decreases markedly after oviposition, and the glands are inactive by the summer months. Ambystoma opacum is a terrestrial breeder, and some mating occurs prior to arrival at pond basins where oviposition occurs. Mating prior to arrival at the ovipository site may prolong the breeding season, leading to fitness implications for both males and females. Females have opportunities for more matings, and the possibilities for sperm competition in the spermathecae are enhanced. © 1995 Wiley-Liss, Inc. Copyright © 1995 Wiley-Liss, Inc.

  16. Effects of metamorphosis and captivity on the in vitro sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin

    International Nuclear Information System (INIS)

    Norman, M.F.; Norris, D.O.

    1987-01-01

    The sensitivity of thyroid glands from the tiger salamander, Ambystoma tigrinum, to bovine thyrotropin (bTSH) was tested in vitro. Thyroids were taken from subjects representing metamorphic stages I (premetamorphic larvae), II (onset of climax), and VII (completion of gill resorption), as well as from captivity control larvae. Exogenous TSH reduced the cumulative uptake of 125 I in vitro by thyroids from stage I larvae after 24 and 48 hr. The capacity of thyroids to release thyroxine (T4) in vitro was used subsequently as a measure of their responsiveness to TSH. Baseline levels of T4 release in vitro were variable but did not differ significantly among developmental stages. A low dose of bTSH (5 X 10(-6) IU/ml) did not increase in vitro T4 release compared with that of controls. A larger dose (5 X 10(-4) IU/ml) caused greater increases in T4 release from thyroids of stage II and VII subjects than from those of controls. This dose produced only a small response by thyroids from captivity-control subjects. The results suggest that the thyroids of Ambystoma increase in their capacity to respond to TSH during the process of metamorphosis

  17. Hungry Horse Dam Fisheries Mitigation : Fish Passage and Habitat Improvement in the Upper Flathead River Basin, 1991-1996 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Knotek, W.Ladd; Deleray, Mark; Marotz, Brian L.

    1997-08-01

    In the past 50 years, dramatic changes have occurred in the Flathead Lake and River system. Degradation of fishery resources has been evident, in part due to deterioration of aquatic habitat and introduction of non-endemic fish and invertebrate species. Habitat loss has been attributed to many factors including the construction and operation of Hungry Horse Dam, unsound land use practices, urban development, and other anthropogenic and natural disturbances. Fish migration has also been limited by barriers such as dams and impassible culverts. Cumulatively, these factors have contributed to declines in the distribution and abundance of native fish populations. Recovery of fish populations requires that a watershed approach be developed that incorporates long-term aquatic habitat needs and promotes sound land use practices and cooperation among natural resource management agencies. In this document, the authors (1) describe completed and ongoing habitat improvement and fish passage activities under the Hungry Horse Fisheries Mitigation Program, (2) describe recently identified projects that are in the planning stage, and (3) develop a framework for identifying prioritizing, implementing, and evaluating future fish habitat improvement and passage projects.

  18. Effects of the Operation of Hungry Horse Dam on the Kokanee Fishery in the Flathead River System, 1984 Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Fraley, John J.

    1984-12-01

    This study assessed the effects of the operation of Hungry Horse Dam on the kokanee fishery in the Flathead River system. This report covers the 1983-84 field season concerning the effects of Hungry Horse operations on kokanee abundance and reproductive success in the upper Flathead River system. This report also addresses the projected recovery of the main stem kokanee run under the flow regime recommended by the Department of Fish, Wildlife and Parks and implemented by the Bureau of Reclamation and Bonneville Power Administration in 1982. An estimated 58,775 kokanee reached spawning grounds in the Flathead River System in 1983. The 1983 spawning run was composed of 92% age III + fish, as compared to an average of 80% from 1972-1983. A total of 6883 kokanee redds were enumerated in the main stem Flathead River in 1983. A total of 2366 man-days of angling pressure was estimated during the 1983 kokanee lure fishery in the Flathead River system. Estimated numbers of fry emigrating from McDonald Creek, the Whitefish River and Brenneman's Slough were 13,100,000, 66,254 and 37,198, yielding egg to fry survival rates of 76%, 10.4% and 19.2%.

  19. Effects of the Operation of Kerr and Hungry Horse Dams on the Kokanee Fishery in the Flathead River System, 1979-1985 Final Research Report.

    Energy Technology Data Exchange (ETDEWEB)

    Clancy, Patrick

    1986-05-01

    This study was undertaken to assess the effects of the operation of Hungry Horse Dam on the kokanee fishery in the Flathead River system. Studies concerning operation of the dam on the Flathead River aquatic biota began in 1979 and continued to 1982 under Bureau of Reclamation funding. These studies resulted in flow recommendations for the aquatic biota in the main stem Flathead River, below the influence of Hungry Horse Dam on the South Fork. Studies concerned specifically with kokanee salmon have continued under Bonneville Power Administration funding since 1982. This completion report covers the entire study period (September 1979 to June 1985). Major results of this study were: (1) development and refinement of methods to assess hydropower impacts on spawning and incubation success of kokanee; (2) development of a model to predict kokanee year class strength from Flathead River flows; and (3) implementation of flows favorable for successful kokanee reproduction. A monitoring program has been developed which will assess the recovery of the kokanee population as it proceeds, and to recommend management strategies to maintain management goals for the kokanee fishery in the river system.

  20. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suprressed by X-irradiation

    International Nuclear Information System (INIS)

    Teplits, N.A.

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state. (E.T.)

  1. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suppressed by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Teplits, N A [AN SSSR, Moscow. Inst. Biologii Razvitiya

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state.

  2. A populational survey of 45S rDNA polymorphism in the Jefferson salamander Ambystoma jeffersonianum revealed by fluorescence in situ hybridization (FISH

    Directory of Open Access Journals (Sweden)

    Jinzhong FU

    2009-04-01

    Full Text Available The chromosomal localization of 45S ribosomal RNA genes in Ambystoma jeffersonianum was determined by fluorescence in situ hybridization with 18S rDNA fragment as a probe (FISH-rDNA. Our results revealed the presence of rDNA polymorphism among A.jeffersonianum populations in terms of number, location and FISH signal intensity on the chromosomes. Nine rDNA cytotypes were found in ten geographically isolated populations and most of them contained derivative rDNA sites. Our preliminary study provides strong indication of karyotypic diversification of A.jeffersonianum that is demonstrated by intraspecific variation of 45S rDNA cytotypes. rDNA cytotype polymorphism has been described in many other caudate amphibians. We predict that habitat isolation, low dispersal ability and decline of effective population size could facilitate the fixation and accumulation of variable rDNA cytotypes during their chromosome evolution.

  3. Regeneración miocárdica en Ambystoma mexicanum después de lesión quirúrgica

    OpenAIRE

    Vargas-González, Alvaro; Prado-Zayago, Esteban; León-Olea, Martha; Guarner-Lans, Verónica; Cano-Martínez, Agustina

    2005-01-01

    Se realizó resección ventricular en el corazón de Ambystoma mexicanum, se evaluó si la restitución del tejido resulta de hipertrofia o de hiperplasia. Por medio de una tinción tricrómica se encontró que 5 días después del daño en el espacio de la resección se encontró un coágulo rodeado de fibras de colágena (83 ± 6%), músculo (10 ± 3%) y zonas sin tejido (7 ± 2%). Una proporción de 50 ± 4 y 90 ± 2% correspondió a tejido muscular 10 y 30 días después de la lesión. La tinción con bis-Benzimida...

  4. The green against hungry

    International Nuclear Information System (INIS)

    Slovak, K.

    2007-01-01

    In this paper author deals with the instruction of the European Commission about using of renewable energy (20 %) in European Union up to 2020 and share of biological components in fuels should be 5.75 % up to 2010. However, is it really advantageous to produce bio-fuels? So the scientists found, that e. g. by production of ethanol from corn in 29 per cent more energy is consumed as final product contains. It is similar also by production of bio-oil. Production of bio-oil from soya consumes in 27 per cent more energy from fossil fuels as it is possible to use from final biological product. In the present time the Swedish turnip is grown on the fivefold larger area as five years ago. More than tenth of silviculture soil in Germany is sowed by Swedish turnip. However, bio-oil produced from Swedish turnip grown on this area reaches only two-percent share on total consumption of oil. And just here also another problem is hidden, of which already several non-governmental organisations warn. Is concerned about cultivation of energetic plants at the expense of other plants, which can be used in food industry. In European Union there is not sufficiency of soil to cover the given shares of biological fuel on total consumption from own production. According to German protectionist organisation the Save wildwood the energetic plants can harm natural ecosystems. This organisation presents as example the soya plantages, because of which Amazon wildwood is cut down. Question of climatic changes, which the countries of north hemisphere decided to solve, can't be handled according them thereby, that new problems are formed in developing countries

  5. Quantification of Hungry Horse Reservoir Water Levels Needed to Maintain or Enhance Reservoir Fisheries; Methods and Data, 1983-1987 Summary Report.

    Energy Technology Data Exchange (ETDEWEB)

    May, Bruce; Michael, Gary; Wachsmuth, John (Montana Department of Fish, Wildlife and Parks, Kalispell, MT)

    1988-06-01

    The Hungry Horse Reservoir study is part of the Northwest Power Planning Council's resident fish and wildlife plan. The plan is responsible for mitigating damages to the fish and wildlife resources caused by hydroelectric development in the Columbia River Basin. The major goal of our study is to quantify seasonal water levels needed to maintain or enhance the reservoir fishery. This study began in May, 1983, and the initial phase will be completed July, 1988. This report summarizes limnological, fish abundance, fish distribution and fish food habits data collected from 1983 to 1988. The effect of reservoir operation upon fish habitat, fish food organisms and fish growth is discussed. 71 refs., 36 figs., 46 tabs.

  6. Role of habitat complexity in predator-prey dynamics between an introduced fish and larval Long-toed Salamanders (Ambystoma macrodactylum)

    Science.gov (United States)

    Kenison, Erin K; Litt, Andrea R.; Pilliod, David S.; McMahon, Tom E

    2016-01-01

    Predation by nonnative fishes has reduced abundance and increased extinction risk for amphibian populations worldwide. Although rare, fish and palatable amphibians have been observed to coexist where aquatic vegetation and structural complexity provide suitable refugia. We examined whether larval long-toed salamanders (Ambystoma macrodactylum Baird, 1849) increased use of vegetation cover in lakes with trout and whether adding vegetation structure could reduce predation risk and nonconsumptive effects (NCEs), such as reductions in body size and delayed metamorphosis. We compared use of vegetation cover by larval salamanders in lakes with and without trout and conducted a field experiment to investigate the influence of added vegetation structure on salamander body morphology and life history. The probability of catching salamanders in traps in lakes with trout was positively correlated with the proportion of submerged vegetation and surface cover. Growth rates of salamanders in enclosures with trout cues decreased as much as 85% and the probability of metamorphosis decreased by 56%. We did not find evidence that adding vegetation reduced NCEs in experimental enclosures, but salamanders in lakes with trout utilized more highly-vegetated areas which suggests that adding vegetation structure at the scale of the whole lake may facilitate coexistence between salamanders and introduced trout.

  7. Effect of the Operation of Kerr and Hungry Horse Dams on the Reproductive Success of Kokanee in the Flathead System; Technical Addendum to the Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, Will; Tohtz, Joel

    1990-03-01

    This addendum to the Final Report presents results of research on the zooplankton and fish communities of Flathead Lade. The intent of the Study has been to identify the impacts of hydroelectric operations at Kerr and Hungry Horse Dam on the reproductive success of kokanee an to propose mitigation for these impacts. Recent changes in the trophic ecology of the lake, have reduced the survival of kokanee. In the last three year the Study has been redirected to identify, if possible, the biological mechanisms which now limit kokanee survival, and to test methods of enhancing the kokanee fishery by artificial supplementation. These studies were necessary to the formulation of mitigation plans. The possibility of successfully rehabilitating the kokanee population, is the doubt because of change in the trophic ecology of the system. This report first presents the results of studies of the population dynamics of crustacean zooplankton, upon which planktivorous fish depend. A modest effort was directed to measuring the spawning escapement of kokanee in 1988. Because of its relevance to the study, we also report assessments of 1989 kokanee spawning escapement. Hydroacoustic assessment of the abundance of all fish species in Flathead Lake was conducted in November, 1988. Summary of the continued efforts to document the growth rates and food habits of kokanee and lake whitefish are included in this report. Revised kokanee spawning and harvest estimates, and management implications of the altered ecology of Flathead Lake comprise the final sections of this addendum. 83 refs., 20 figs., 25 tabs.

  8. Effect of the Operation of Kerr and Hungry Horse Dams on the Reproductive Success of Kokanee in the Flathead System, 1987 Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, Will; Zubik, Raymond; Clancey, Patrick

    1988-05-01

    Studies of kokanee reproductive success in the Flathead system from 1981 to 1987 have assessed the losses in fish production attributable to hydroelectric operations. We estimated that the Flathead Lake shoreline spawning stock has lost at least 50,000 fish annually, since Kerr Dam was completed in 1938. The Flathead River spawning stock has lost 95,000 spawners annually because of the operations of Hungry Horse Dam. Lakeshore spawning has been adversely affected because Flathead Lake has been drafted to minimum pool during the winter when kokanee eggs are incubating in shallow shoreline redds. Egg mortality from exposure and desiccation of kokanee redds has increased since the mid 1970's. When the lake was drafted more quickly and held longer at minimum pool. Escapement surveys in the early 1950's, and a creel survey in the early 1960's have provided a baseline to which the present escapement levels can be compared, and loss estimated. Main stem Flathead River spawning has also declined since the mid 1970's when fluctuating discharge from Hungry Horse Dam during the spawning and incubation season exposed redds at the river margin and increased mortality. This decline followed an increase in main stem spawning in the late 1950's through the mid 1960's attributable to higher winter water temperature and relatively stable discharge from Hungry Horse Dam. Spawning escapement in the main stem exceeded 300,000 kokanee in the early 1970's as a result. Spawning in spring-influenced sites has comprised 35 percent of the main stem escapement from 1979 to 1986. We took that proportion of the early 1970's escapement (105,000) as the baseline against which to measure historic loss. Agricultural and suburban development has contributed less significantly to degradation of kokanee spawning habitat in the river system and on the Flathead Lake shoreline. Their influence on groundwater quality and substrate composition has limited

  9. Ion transport by the amphibian primary ureter

    DEFF Research Database (Denmark)

    Møbjerg, Nadja

    2008-01-01

    putative ion transport mechanisms in the primary ureter of the freshwater amphibian Ambystoma mexicanum (axolotl). Primary ureters isolated from axolotl larvae were perfused in vitro and single cells were impaled across the basal cell membrane with glass microelectrodes. In 42 cells the membrane potential......+] steps from 3 to 20 mmol/l and a hyperpolarization of Vm upon lowering [Na+] from 102 to 2 mmol/l, indicating the presence of luminal K+ and Na+ conductances. This study provides the first functional data on the vertebrate primary ureter. The data show that the primary ureter of axolotl larvae...

  10. Hungry Tiger Eager To Grow

    Science.gov (United States)

    2015-06-01

    For example, in the Indian security perspective, China was a potential threat and motivated India to ruminate over the question of nuclear...a secretary of defense in the Clinton administration, contends that “India sees itself in a different light—not looking so much inward and looking...has undertaken several high-profile deployments to the South China Sea and the Persian Gulf,” and he contends that such deployments are significant

  11. Effect of the Operation of Kerr and Hungry Horse Dams on the Reproduction Success of Kokanee in the Flathead River System, 1986 Annual Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, Will; Clancey, Patrick

    1987-03-01

    Flathead Lake. Our results show that egg survival in the river has improved in response to stabilized discharge from Hungry Horse Dam. Drawdown exposure continues to limit egg survival in lakeshore redds. Study of the variability in growth and survival of young-of-the-year fish in Flathead Lake will further the understanding of factors which cause fluctuation in the kokanee population.

  12. Genic regions of a large salamander genome contain long introns and novel genes

    Directory of Open Access Journals (Sweden)

    Bryant Susan V

    2009-01-01

    Full Text Available Abstract Background The basis of genome size variation remains an outstanding question because DNA sequence data are lacking for organisms with large genomes. Sixteen BAC clones from the Mexican axolotl (Ambystoma mexicanum: c-value = 32 × 109 bp were isolated and sequenced to characterize the structure of genic regions. Results Annotation of genes within BACs showed that axolotl introns are on average 10× longer than orthologous vertebrate introns and they are predicted to contain more functional elements, including miRNAs and snoRNAs. Loci were discovered within BACs for two novel EST transcripts that are differentially expressed during spinal cord regeneration and skin metamorphosis. Unexpectedly, a third novel gene was also discovered while manually annotating BACs. Analysis of human-axolotl protein-coding sequences suggests there are 2% more lineage specific genes in the axolotl genome than the human genome, but the great majority (86% of genes between axolotl and human are predicted to be 1:1 orthologs. Considering that axolotl genes are on average 5× larger than human genes, the genic component of the salamander genome is estimated to be incredibly large, approximately 2.8 gigabases! Conclusion This study shows that a large salamander genome has a correspondingly large genic component, primarily because genes have incredibly long introns. These intronic sequences may harbor novel coding and non-coding sequences that regulate biological processes that are unique to salamanders.

  13. Feeding a hungry world through science

    International Development Research Centre (IDRC) Digital Library (Canada)

    kferguson

    significantly reduce post-harvest losses of nutrient-rich mangoes. ... babwe, and even the United States have expressed interest. The project is also ... practices can increase yields and profits for farmers in the dry, rural regions of Kenya.

  14. Ultrasound for critical care physicians: hungry heart

    Directory of Open Access Journals (Sweden)

    Villalobos N

    2016-01-01

    Full Text Available No abstract available. Article truncated after 150 words. A 31-year-old incarcerated man with a past medical history of intravenous drug use and hepatitis C, presented with a one week history of dry, non-productive cough, orthopnea and exertional dyspnea. He denied current intravenous drug use, and endorsed that the last time he used was before he was incarcerated over 3 years ago, his last tattoo was in prison, 6 months prior. He was found to have an oxygen saturation of 77% on room air, fever of 40º C, heart rate of 114 bpm, and blood pressure of 80/50 mmHg. The patient had a leukocytosis of 14 x109/L, and a chest x-ray demonstrating patchy airspace disease. Blood cultures were sent and he was treated with antibiotics and vasopressors for septic shock. The patient was intubated for acute hypoxemic respiratory failure secondary to multifocal pneumonia. A bedside transthoracic echocardiogram was performed. What is the likely diagnosis supported by the echocardiogram? 1. ...

  15. Intrauterine Growth Restriction: Hungry for an Answer

    Science.gov (United States)

    Chu, Alison

    2016-01-01

    Intrauterine growth restriction (IUGR) has been defined in several ways, but in general describes a condition in which the fetus exhibits poor growth in utero. This complication of pregnancy poses a significant public health burden as well as increased morbidity and mortality for the offspring. In human IUGR, alteration in fetal glucose and insulin homeostasis occurs in an effort to conserve energy and survive at the expense of fetal growth in an environment of inadequate nutrient provision. Several animal models of IUGR have been utilized to study the effects of IUGR on fetal glucose handling, as well as the postnatal reprogramming of energy metabolite handling, which may be unmasked in adulthood as a maladaptive propensity for cardiometabolic disease. This developmental programming may be mediated in part by epigenetic modification of essential regulators of glucose homeostasis. Several pharmacological therapies and nonpharmacological lifestyle modifications have shown early promise in mitigating the risk for or severity of adult metabolic phenotypes but still require further study of unanticipated and/or untoward side effects. PMID:26889018

  16. Hungry Neurons: Metabolic Insights on Seizure Dynamics

    Directory of Open Access Journals (Sweden)

    Paolo Bazzigaluppi

    2017-10-01

    Full Text Available Epilepsy afflicts up to 1.6% of the population and the mechanisms underlying the appearance of seizures are still not understood. In past years, many efforts have been spent trying to understand the mechanisms underlying the excessive and synchronous firing of neurons. Traditionally, attention was pointed towards synaptic (dysfunction and extracellular ionic species (dysregulation. Recently, novel clinical and preclinical studies explored the role of brain metabolism (i.e., glucose utilization of seizures pathophysiology revealing (in most cases reduced metabolism in the inter-ictal period and increased metabolism in the seconds preceding and during the appearance of seizures. In the present review, we summarize the clinical and preclinical observations showing metabolic dysregulation during epileptogenesis, seizure initiation, and termination, and in the inter-ictal period. Recent preclinical studies have shown that 2-Deoxyglucose (2-DG, a glycolysis blocker is a novel therapeutic approach to reduce seizures. Furthermore, we present initial evidence for the effectiveness of 2-DG in arresting 4-Aminopyridine induced neocortical seizures in vivo in the mouse.

  17. Hungry Neurons: Metabolic Insights on Seizure Dynamics

    OpenAIRE

    Paolo Bazzigaluppi; Azin Ebrahim Amini; Iliya Weisspapir; Bojana Stefanovic; Peter L. Carlen

    2017-01-01

    Epilepsy afflicts up to 1.6% of the population and the mechanisms underlying the appearance of seizures are still not understood. In past years, many efforts have been spent trying to understand the mechanisms underlying the excessive and synchronous firing of neurons. Traditionally, attention was pointed towards synaptic (dys)function and extracellular ionic species (dys)regulation. Recently, novel clinical and preclinical studies explored the role of brain metabolism (i.e., glucose utilizat...

  18. Food industry hungry for energy savings

    Energy Technology Data Exchange (ETDEWEB)

    Blackburn, D

    1989-04-01

    The United Kingdom food and drink industry is a significant user of energy. Energy use figures are given showing the breakdown in terms of different sectors of the industry and also in terms of the fuel used. Four energy monitoring and target setting demonstration projects are outlined at factories typical of their type in different sectors. The projects have resulted in a much greater awareness by management in the factories involved of energy consumption and waste. Examples are given of improved energy efficiency and consequent energy savings which have resulted from this awareness. (U.K.).

  19. The Hungry Worm Feeds the Bird

    NARCIS (Netherlands)

    Onrust, J.; Piersma, T.

    2017-01-01

    Earthworms (Lumbricidae) are important prey for many birds. Based on theirown feeding ecology, earthworms can be separated into two ecotypes: the detritivoresthat feed on organic material and the geophages that feed on soil particlesand organic matter. Detritivores collect their food on the surface

  20. A Hungry Quasar Caught in the Act

    Science.gov (United States)

    2001-05-01

    The VLT Secures Spectacular Image of Distant Gravitational Interaction Summary A new image of a distant quasar (the luminous core of an "active" galaxy) shows that it is engaged in a gravitational battle with its neighbouring galaxies . It also provides information on how supermassive black holes present in the center of quasars are fed. Using the FORS2 multi-mode instrument at the ESO 8.2-m VLT KUEYEN telescope on Paranal (Chile), a team of German astronomers [1] obtained a spectacular image of the close and complex environment of the distant quasar "HE 1013-2136", located some 10 billion light-years away [2]. The remarkable structures revealed in this photo lend support to the hypothesis that quasar activity is connected to gravitational interaction between galaxies, already at this early epoch of the Universe (about 5 billion years after the Big Bang). PR Photo 20a/01 : A VLT image of the Quasar HE 1013-2136 . PR Photo 20b/01 : A sharpened version of the same image. Feeding the Black Hole "Quasars" (Quasi-Stellar Objects) were first discovered by Dutch-American astronomer Maarten Schmidt in 1963 as distant, energetic objects of star-like appearance. Since then, more than 15,000 quasars have been found and we now know that they are the luminous cores at the heart of distant galaxies. Such "Active Galactic Nuclei (AGN)" are thought to host Supermassive Black Holes of up to one billion solar masses at their centres. Black Holes represent the densest possible state of matter; if the Earth were to become one, it would measure no more than a few millimetres across. The Black Hole in a galaxy gobbles up the gas and dust of its host, a process that efficiently powers the luminous core that we observe as a point-like "quasar". A Black Hole must be continuously fed to remain active. During an active phase of typically 100 million years, the Black Hole in a quasar swallows material with a total weight of up to 10 solar masses every year. This may be predominantly in the form of gas and dust that happen to come too close to the hole. Our own galaxy, the Milky Way, is also very likely to harbour a Black Hole at its center. However, this hole apparently lacks material to swallow and is somewhat starved - in any case it is much less active than some holes in other galaxies. A key question in connection with the quasar phenomenon is therefore to understand how a large amount of material can be brought towards the center of the host galaxy . Most astronomers believe that disturbances caused by gravitational interaction with neighbouring galaxies constitute a triggering mechanism for fueling the centers of Active Galaxies. The efficiency of such tidal interactions taking place of course depends on how many galaxies are located in the immediate neighbourhood of the quasar as well as on the relative velocities of the quasar host and its companions. Searching for quasar companions ESO PR Photo 20a/01 ESO PR Photo 20a/01 [Preview - JPEG: 400 x 452 pix - 304k] [Normal - JPEG: 800 x 900 pix - 744k] ESO PR Photo 20b/01 ESO PR Photo 20b/01 [Preview - JPEG: 400 x 452 pix - 208k] [Normal - JPEG: 800 x 898 pix - 460k] Caption : PR Photo 20a/01 shows an image of the Quasar HE 1013-2136 (center) and its surroundings, as obtained with the FORS2 multi-mode instrument at the 8.2-m VLT KUEYEN telescope in February 2001. A spectacular arc-like tidal tail stretches from the quasar towards south-east (lower-left) over a distance of more than 150,000 light-years. Another, shorter tidal tail towards the east-northeast is barely visible. PR Photo 20b/01 shows the same field, but sharpened with a computer algorithm to bring out more details in the immediate neighbourhood of the quasar. Now numerous details can be recognized within the two tidal tails, including various knotty structures. In particular, a very close companion galaxy at 20,000 light-years projected distance to the quasar can now be seen (at the 5 o'clock position) that may be in gravitational interaction with the quasar host galaxy. Quasar activity is believed to be triggered by such dramatic events. Since some time, astronomers have therefore been searching for clear evidence for a connection between gravitational interaction and the quasar phenomenon. However, quasars are very bright objects and their light easily outshines all nearby objects. Any companion galaxies and structural features that may indicate interaction are therefore hard to detect. While observations with the Hubble Space Telescope (HST) have much improved our knowledge of the interaction-activity connection in some relatively nearby quasars, it has been difficult to probe the same phenomenon in more distant quasar environments. Such studies clearly require larger telescopes. The observations of the quasar HE 1013-2136 presented here result from a new programme that addresses this issue at earlier cosmic epochs. This 17-mag object is seen in the southern constellation Hydra (The Water Snake) and is located at a distance of about 10 billion light years (the redshift is z = 0.785) PR Photo 20a/01 shows an image of HE 1013-2136 and its immediate surroundings, obtained with the FORS2 multi-mode instrument at the 8.2-m VLT KUEYEN telescope under very good seeing conditions. The image resolution is about 0.6 arcsec, or about 10,000 light-years at the distance of the quasar. The image has been further sharpened by means of image processing software (the Lucy algorithm) in PR Photo 20b/01 , now also showing the distribution of objects very close to the bright quasar image. This impressively illustrates the light gathering and resolution power of the VLT. Tidal forces at HE 1013-2136 The quasar is the point-like object at the center of the images. It is embedded within a complex structure that mainly consists of two arc-like and knotty tails extending in different directions. Such tails are well-known from nearby galaxy interactions, cf. NGC 6872/IC4970 and are a consequence of tidal forces in the gravitational field of the galaxies. The astronomers believe that the two tidal tails result from a dramatic interaction between the quasar host galaxy and one or more of the close companion galaxies. The longer, southern tail extends over more than 150,000 light years, one-and-a-half times the diameter of the Milky Way. In many respects this distant interaction resembles the well known Antenna Galaxies (see the Hubble image ), where two nearby galaxies distort each other in a gravitational dance. Galaxy mergers in the young Universe In the case of HE 1013-2136 , a number of knots can be seen along both tidal tails. In particular, the object just below the quasar image, most easily seen in the sharpened image ( PR Photo 20b/01 ), lies at a projected distance of only 20,000 light years. This is about two-thirds of the distance from the Earth to the center of the Milky Way galaxy. This object is most likely a companion that is interacting with the quasar host. Recent observations of nearby quasars have revealed that they mostly reside in elliptical galaxies . Numerical simulations suggest that such galaxies can be formed by successive mergers of spiral galaxies. Klaus Jäger and his colleagues point out that " with the VLT observations of HE 1013-2136 , we may be directly witnessing such a dramatic merger of galaxies. The special significance of this observation is the great distance and hence the comparably early time at which this happens, when the Universe was about one third as old as it is now ". He adds: " This particular galaxy will most probably evolve into the same type of elliptical quasar host galaxy that we observe much nearer to us, that is, at much later times ". Notes [1] The team is composed of Klaus Jäger , Klaus J. Fricke (both Universitäts-Sternwarte Göttingen, Germany), Jochen Heidt and Immo Appenzeller (both Landessternwarte Heidelberg, Germany). [2] 1 billion = 1,000 million Technical information about the photos PR Photo 20a/01 is based on an image that was obtained in the morning of February 26, 2001 with the FORS2 instrument on VLT KUEYEN. It is composed of eight exposures in the I-band filter (effective wavelength 768 nm; FWHM 138 nm), lasting a total of 32 min. The combined image has a FWHM of 0.6 arcsec. In PR Photo 20b/01 this image has been processed by applying the Lucy algorithm with 15 iterations. The field shown measures 33 x 33 arcsec 2 , or 540,000 x 540,000 light-years 2 projected at the distance of the quasar; 1 pixel = 0.2 arcsec. North is up and East is left.

  1. Microarray analysis of a salamander hopeful monster reveals transcriptional signatures of paedomorphic brain development

    Science.gov (United States)

    2010-01-01

    Background The Mexican axolotl (Ambystoma mexicanum) is considered a hopeful monster because it exhibits an adaptive and derived mode of development - paedomorphosis - that has evolved rapidly and independently among tiger salamanders. Unlike related tiger salamanders that undergo metamorphosis, axolotls retain larval morphological traits into adulthood and thus present an adult body plan that differs dramatically from the ancestral (metamorphic) form. The basis of paedomorphic development was investigated by comparing temporal patterns of gene transcription between axolotl and tiger salamander larvae (Ambystoma tigrinum tigrinum) that typically undergo a metamorphosis. Results Transcript abundances from whole brain and pituitary were estimated via microarray analysis on four different days post hatching (42, 56, 70, 84 dph) and regression modeling was used to independently identify genes that were differentially expressed as a function of time in both species. Collectively, more differentially expressed genes (DEGs) were identified as unique to the axolotl (n = 76) and tiger salamander (n = 292) than were identified as shared (n = 108). All but two of the shared DEGs exhibited the same temporal pattern of expression and the unique genes tended to show greater changes later in the larval period when tiger salamander larvae were undergoing anatomical metamorphosis. A second, complementary analysis that directly compared the expression of 1320 genes between the species identified 409 genes that differed as a function of species or the interaction between time and species. Of these 409 DEGs, 84% exhibited higher abundances in tiger salamander larvae at all sampling times. Conclusions Many of the unique tiger salamander transcriptional responses are probably associated with metamorphic biological processes. However, the axolotl also showed unique patterns of transcription early in development. In particular, the axolotl showed a genome-wide reduction in mRNA abundance

  2. Microarray analysis of a salamander hopeful monster reveals transcriptional signatures of paedomorphic brain development

    Directory of Open Access Journals (Sweden)

    Putta Srikrishna

    2010-06-01

    Full Text Available Abstract Background The Mexican axolotl (Ambystoma mexicanum is considered a hopeful monster because it exhibits an adaptive and derived mode of development - paedomorphosis - that has evolved rapidly and independently among tiger salamanders. Unlike related tiger salamanders that undergo metamorphosis, axolotls retain larval morphological traits into adulthood and thus present an adult body plan that differs dramatically from the ancestral (metamorphic form. The basis of paedomorphic development was investigated by comparing temporal patterns of gene transcription between axolotl and tiger salamander larvae (Ambystoma tigrinum tigrinum that typically undergo a metamorphosis. Results Transcript abundances from whole brain and pituitary were estimated via microarray analysis on four different days post hatching (42, 56, 70, 84 dph and regression modeling was used to independently identify genes that were differentially expressed as a function of time in both species. Collectively, more differentially expressed genes (DEGs were identified as unique to the axolotl (n = 76 and tiger salamander (n = 292 than were identified as shared (n = 108. All but two of the shared DEGs exhibited the same temporal pattern of expression and the unique genes tended to show greater changes later in the larval period when tiger salamander larvae were undergoing anatomical metamorphosis. A second, complementary analysis that directly compared the expression of 1320 genes between the species identified 409 genes that differed as a function of species or the interaction between time and species. Of these 409 DEGs, 84% exhibited higher abundances in tiger salamander larvae at all sampling times. Conclusions Many of the unique tiger salamander transcriptional responses are probably associated with metamorphic biological processes. However, the axolotl also showed unique patterns of transcription early in development. In particular, the axolotl showed a genome

  3. Radioautographic investigation of retinal growth in mature amphibians

    International Nuclear Information System (INIS)

    Svistunov, S.A.; Mitashov, V.I.

    1986-01-01

    Growth of the retina was studied in mature intact amphibians, tritons, axolotls, ambystomas and clawed frogs, for six months using multiple injection of 3 H-thymidine. It was established that the source of replenishment of the retina by new cells is its terminal zone in all animals investigated. This is attested to by the gradual migration of labeled cells from the growth zone into differentiated layers of the retina. The most intensely labeled cells occupy a distal position relative to other labeled cells, therefore marking the boundary between the initial part of the retina, not containing labeled nuclei, and the part being augmented. For each species studied, a level of proliferative activity is characteristic for cells of the terminal zone, which decreases in the order axolotl-clawed frog-triton -ambystoma. In the axolotl and additional growth zone is noted in the retina, in addition to the terminal, which is located in the area of the unclosed section of the embryonic fissure. Results obtained serve as a basis for the regenerative potentials of eye tissues revealed previously in these amphibian species

  4. Origin of amphibian and avian chromosomes by fission, fusion, and retention of ancestral chromosomes

    Science.gov (United States)

    Voss, Stephen R.; Kump, D. Kevin; Putta, Srikrishna; Pauly, Nathan; Reynolds, Anna; Henry, Rema J.; Basa, Saritha; Walker, John A.; Smith, Jeramiah J.

    2011-01-01

    Amphibian genomes differ greatly in DNA content and chromosome size, morphology, and number. Investigations of this diversity are needed to identify mechanisms that have shaped the evolution of vertebrate genomes. We used comparative mapping to investigate the organization of genes in the Mexican axolotl (Ambystoma mexicanum), a species that presents relatively few chromosomes (n = 14) and a gigantic genome (>20 pg/N). We show extensive conservation of synteny between Ambystoma, chicken, and human, and a positive correlation between the length of conserved segments and genome size. Ambystoma segments are estimated to be four to 51 times longer than homologous human and chicken segments. Strikingly, genes demarking the structures of 28 chicken chromosomes are ordered among linkage groups defining the Ambystoma genome, and we show that these same chromosomal segments are also conserved in a distantly related anuran amphibian (Xenopus tropicalis). Using linkage relationships from the amphibian maps, we predict that three chicken chromosomes originated by fusion, nine to 14 originated by fission, and 12–17 evolved directly from ancestral tetrapod chromosomes. We further show that some ancestral segments were fused prior to the divergence of salamanders and anurans, while others fused independently and randomly as chromosome numbers were reduced in lineages leading to Ambystoma and Xenopus. The maintenance of gene order relationships between chromosomal segments that have greatly expanded and contracted in salamander and chicken genomes, respectively, suggests selection to maintain synteny relationships and/or extremely low rates of chromosomal rearrangement. Overall, the results demonstrate the value of data from diverse, amphibian genomes in studies of vertebrate genome evolution. PMID:21482624

  5. The Hungry Brain: The Nutrition/Cognition Connection

    Science.gov (United States)

    Marcus, Susan Archibald

    2007-01-01

    The brain gets fed first! That is an important idea that directly relates to the nutrition/cognition connection in schools. As the education community faces the challenges of childhood obesity, malnutrition of the brain, food allergies, disorders of metal metabolism and biochemical imbalances, educators are eager to learn about how to guide…

  6. How Is the Hungry Brain like a Sieve?

    OpenAIRE

    Myers, Martin G.

    2013-01-01

    Whether some hypothalamic neurons have direct access to circulating metabolic cues represents a crucial question that has been intensely debated. New findings reveal that fasting promotes “leakiness” of some hypothalamic blood vessels, increasing the access of circulating factors to certain hypothalamic neurons that control feeding (Langlet et al., 2013).

  7. Breakthrough supplies young fish to a hungry industry | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2010-10-28

    Oct 28, 2010 ... Southeast Asian Fisheries Development Centre (SEAFDEC) ... Research at SEAFDEC positively impacts on milkfish industry · Milkfish ... An important source of animal protein, it is vital to the country's food security.

  8. Hungry granulocyte: its fate and regulation of production

    International Nuclear Information System (INIS)

    Cronkite, E.P.

    1978-01-01

    The granulocyte, a phagocytic anti-1 bacterial defense cell, is discussed. Its production, the kinetics of its proliferation, the regulation of its production, and its loss from the blood are reviewed

  9. World Hunger Crisis Kit. Hope for the Hungry.

    Science.gov (United States)

    Woito, Robert, Ed.

    This booklet introduces the problem of world hunger and provides information, facts, and perspectives about the crisis. Section one presents the reader with the basic facts of the hunger crisis through a self-survey, a statistical study of the developed Oil Producing Export Countries (OPEC), and a one-page indication of what one would have to give…

  10. Hungry bone-syndrom ved vitamin D-mangel

    DEFF Research Database (Denmark)

    Chehaiber, Mohamad M; Jensen, Jens-Erik Beck

    2009-01-01

    An 85-year-old woman was admitted after being bedridden for six months with muscular weakness and diarrhoea. Vitamin 25-OH-D, serum calcium, magnesium and phosphate were low, and parathyroid hormone as well as alkaline phosphatase were increased. Dual x-ray absorption scan showed reduced bone...

  11. Resource-Hungry Ad Hoc Wireless etwork simulators

    African Journals Online (AJOL)

    Nafiisah

    The required resources, mainly computing equipment and physical space, are ... Cost of using the simulator is one of the main issues that affect its usage ... node to change its lane; (4) the Manhattan Mobility (MH) Model, which has been introduced to ..... Python. So, J-Sim is a dual-language simulation environment in which ...

  12. ANIMAL PRODUCTION IN A GRAIN HUNGRY WORLD - or ...

    African Journals Online (AJOL)

    ted plant matter. animal products are not essen- tial in human ... the energy of plant matter is lost in converting it to animal .... to electricity or by harnessing wind and wave power. nu- ..... nomy. will also adapt to the changing cost structure by.

  13. Peristaltic pumping in an elastic tube: feeding the hungry python

    Science.gov (United States)

    Takagi, Daisuke; Balmforth, Neil

    2010-11-01

    Biological ducts convey contents like food in the digestive system by peristaltic action, propagating waves of muscular contraction and relaxation. The motion is investigated theoretically by considering a radial force of sinusoidal or Gaussian form moving steadily down a fluid-filled axisymmetric tube. Effects of the prescribed force on the resultant fluid flow and elastic deformation of the tube wall are presented. The flow can induce a rigid object suspended in the fluid to propel in different ways, as demonstrated in numerous examples.

  14. Genomics of a Metamorphic Timing QTL: met1 Maps to a Unique Genomic Position and Regulates Morph and Species-Specific Patterns of Brain Transcription

    Science.gov (United States)

    Page, Robert B.; Boley, Meredith A.; Kump, David K.; Voss, Stephen R.

    2013-01-01

    Very little is known about genetic factors that regulate life history transitions during ontogeny. Closely related tiger salamanders (Ambystoma species complex) show extreme variation in metamorphic timing, with some species foregoing metamorphosis altogether, an adaptive trait called paedomorphosis. Previous studies identified a major effect quantitative trait locus (met1) for metamorphic timing and expression of paedomorphosis in hybrid crosses between the biphasic Eastern tiger salamander (Ambystoma tigrinum tigrinum) and the paedomorphic Mexican axolotl (Ambystoma mexicanum). We used existing hybrid mapping panels and a newly created hybrid cross to map the met1 genomic region and determine the effect of met1 on larval growth, metamorphic timing, and gene expression in the brain. We show that met1 maps to the position of a urodele-specific chromosome rearrangement on linkage group 2 that uniquely brought functionally associated genes into linkage. Furthermore, we found that more than 200 genes were differentially expressed during larval development as a function of met1 genotype. This list of differentially expressed genes is enriched for proteins that function in the mitochondria, providing evidence of a link between met1, thyroid hormone signaling, and mitochondrial energetics associated with metamorphosis. Finally, we found that met1 significantly affected metamorphic timing in hybrids, but not early larval growth rate. Collectively, our results show that met1 regulates species and morph-specific patterns of brain transcription and life history variation. PMID:23946331

  15. entre la pirámide y el axolotl

    Directory of Open Access Journals (Sweden)

    Paula Andrea Marín Colorado

    2006-01-01

    Full Text Available En este artículo se presenta un acercamiento a la novela Materia dispuesta, del escritor mexicano Juan Villoro. En esta aproximación analítica se pretende dilucidar la conexión entre la obra literaria y el medio en el que se gesta, así como con el momento histórico recreado en la anécdota de la novela (el terremoto ocurrido en Ciudad de México en 1985; lo anterior con el objetivo de establecer la propuesta estética del autor en esta obra y su relación con la visión que construye Materia dispuesta sobre los procesos de Modernidad y Postmodernidad en Latinoamérica. Para tal propósito se recurrirá a las investigaciones literarias y sociológicas de Mijail Bajtín, Zigmunt Bauman, Carlos Monsiváis y Octavio Paz, entre otros.

  16. Evolution of the head-trunk interface in tetrapod vertebrates

    Science.gov (United States)

    Sefton, Elizabeth M; Bhullar, Bhart-Anjan S; Mohaddes, Zahra; Hanken, James

    2016-01-01

    Vertebrate neck musculature spans the transition zone between head and trunk. The extent to which the cucullaris muscle is a cranial muscle allied with the gill levators of anamniotes or is instead a trunk muscle is an ongoing debate. Novel computed tomography datasets reveal broad conservation of the cucullaris in gnathostomes, including coelacanth and caecilian, two sarcopterygians previously thought to lack it. In chicken, lateral plate mesoderm (LPM) adjacent to occipital somites is a recently identified embryonic source of cervical musculature. We fate-map this mesoderm in the axolotl (Ambystoma mexicanum), which retains external gills, and demonstrate its contribution to posterior gill-levator muscles and the cucullaris. Accordingly, LPM adjacent to the occipital somites should be regarded as posterior cranial mesoderm. The axial position of the head-trunk border in axolotl is congruent between LPM and somitic mesoderm, unlike in chicken and possibly other amniotes. DOI: http://dx.doi.org/10.7554/eLife.09972.001 PMID:27090084

  17. Carbamoyl-phosphate synthase (ammonia) of rat and axolotl liver: determination of immunological cross-reactivity without purification of the axolotl enzyme

    NARCIS (Netherlands)

    Lamers, W. H.; de Graaf, A.; Mooren, P. G.; Moorman, A. F.; Charles, R.

    1982-01-01

    A method has been developed to establish the degree of cross-reactivity of an antiserum raised against purified carbamoyl-phosphate synthase (ammonia) from adult rat liver, toward a homologous enzyme from another species without purification of the latter enzyme. For that purpose the ratio between

  18. Hungry in hospital, well-fed in prison? A comparative analysis of food service systems.

    Science.gov (United States)

    Johns, Nick; Edwards, John S A; Hartwell, Heather J

    2013-09-01

    Meals served in prisons and hospitals are produced in similar ways and have similar characteristics, yet hospital patients are often at risk of being undernourished, while prisoners typically are not. This article examines field notes collected during nutritional studies of prison and hospital food service, which confirmed the difference in nutrient intake claimed by other authors. A comparison of food service processes and systems showed that the production of meals and the quality leaving the kitchen was similar in both types of institution. However, the delivery and service system was found to be much less coherent in hospital than in prison. Transport and service of hospital food were subject to delays and disruptions from a number of sources, including poor communication and the demands of medical professionals. These meant that meals reached hospital patients in a poorer, less appetising condition than those received by prisoners. The findings are discussed in the light of previous work and in terms of hospital food service practice. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  19. Climate-smart Kenyan crop hits a setback – hungry birds | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2013-08-07

    Aug 7, 2013 ... He says that seeds are a major part of the birds' diet “but they seem .... the Collaborative Adaptation Research Initiative in Africa and Asia, a joint initiative of IDRC and DFID. ... Exploring farmers' perceptions of climate variation and change in ... Au Kenya, des oiseaux nuisent à une culture adaptée au climat.

  20. Variably hungry caterpillars: predictive models and foliar chemistry suggest how to eat a rainforest

    Czech Academy of Sciences Publication Activity Database

    Segar, Simon Tristram; Volf, Martin; Isua, B.; Sisol, M.; Redmond, Conor; Rosati, M. E.; Gewa, B.; Molem, K.; Dahl, Chris; Holloway, J. D.; Basset, Yves; Miller, S. E.; Weiblen, G. D.; Salminen, J.-P.; Novotný, Vojtěch

    2017-01-01

    Roč. 284, č. 1866 (2017), č. článku 20171803. ISSN 0962-8452 R&D Projects: GA ČR(CZ) GA17-23862S; GA ČR GA15-24571S EU Projects: European Commission(XE) 669609 - Diversity6continents Grant - others:European Social Fund(CZ) CZ.1.07/2.3.00/30.0006 Institutional support: RVO:60077344 Keywords : biodiversity * food webs * Geometridae Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.940, year: 2016 http://rspb.royalsocietypublishing.org/content/royprsb/284/1866/20171803.full.pdf

  1. "Hungry Eyes": Visual Processing of Food Images in Adults with Prader-Willi Syndrome

    Science.gov (United States)

    Key, A. P. F.; Dykens, E. M.

    2008-01-01

    Background: Prader-Willi syndrome (PWS) is a genetic disorder associated with intellectual disabilities, compulsivity, hyperphagia and increased risks of life-threatening obesity. Food preferences in people with PWS are well documented, but research has yet to focus on other properties of food in PWS, including composition and suitability for…

  2. Efficient multi-site data movement using constraint programming for data hungry science

    Energy Technology Data Exchange (ETDEWEB)

    Zerola, Michal; Sumbera, Michal [Nuclear Physics Institute, Academy of Sciences of the Czech Republic (Czech Republic); Lauret, Jerome [Brookhaven National Laboratory, Upton (United States); Bartak, Roman, E-mail: michal.zerola@ujf.cas.c, E-mail: jlauret@bnl.go, E-mail: roman.bartak@mff.cuni.c, E-mail: sumbera@ujf.cas.c [Faculty of Mathematics and Physics, Charles University (Czech Republic)

    2010-04-01

    For the past decade, HENP experiments have been heading towards a distributed computing model in an effort to concurrently process tasks over enormous data sets that have been increasing in size as a function of time. In order to optimize all available resources (geographically spread) and minimize the processing time, it is necessary to face also the question of efficient data transfers and placements. A key question is whether the time penalty for moving the data to the computational resources is worth the presumed gain. Onward to the truly distributed task scheduling we present the technique using a Constraint Programming (CP) approach. The CP technique schedules data transfers from multiple resources considering all available paths of diverse characteristic (capacity, sharing and storage) having minimum user's waiting time as an objective. We introduce a model for planning data transfers to a single destination (data transfer) as well as its extension for an optimal data set spreading strategy (data placement). Several enhancements for a solver of the CP model will be shown, leading to a faster schedule computation time using symmetry breaking, branch cutting, well studied principles from job-shop scheduling field and several heuristics. Finally, we will present the design and implementation of a corner-stone application aimed at moving datasets according to the schedule. Results will include comparison of performance and trade-off between CP techniques and a Peer-2-Peer model from simulation framework as well as the real case scenario taken from a practical usage of a CP scheduler.

  3. Attentional bias for food cues in advertising among overweight and hungry children

    NARCIS (Netherlands)

    Folkvord, F.; Anschutz, D.J.; Buijzen, M.A.

    2015-01-01

    Attentional bias theory suggests that an increased motivation to receive or avoid a rewarding substance elevates automatic selective attention toward cues that are related to that specific substance. Until now, no study has examined attentional bias toward food cues in food advertisements, even

  4. Global nutrition 1990-2015: A shrinking hungry, and expanding fat world.

    Science.gov (United States)

    Peng, Wen; Berry, Elliot M

    2018-01-01

    Following its publication in 2008, the Global Nutritional Index (GNI) which captures the triple burden of malnutrition, has been updated to assess the overall nutritional status and nutritional trends of countries, regions and the world, including both under-nutrition and over-nutrition. The GNI was modeled on the Human Development Index, using geometric means of three normalized indicators: protein-energy malnutrition (PEM, measured by Disability-Adjusted Life Years (DALYs) from PEM), micronutrient deficiency (MID, measured by DALYs from MID), and penalizing obesity (percent female obesity). GNI (range 0-1) was calculated from 1990-2015 for 186 countries, in seven World Bank income and WHO region groupings. World GNI increased from 0.433 to 0.473 as decreased deficits overcompensated for the rise in obesity. GNI for African low- and middle-income countries (LMIC) (median 0.301 to 0.392) and South-East Asian LMIC (0.456 to 0.564) improved significantly (Phunger"-"reduce obesity".

  5. When I Was Hungry. A Hunger Course for High School Students. [Student Packet].

    Science.gov (United States)

    Bread for the World Educational Fund, Washington, DC.

    This student packet contains readings and exercises for examining the problem of world hunger. Materials, which are suitable for use by high school students, are presented from a Christian perspective. Twelve chapters cover justice and the right to food; causes of hunger (poverty, land use, the international economy, the arms race, resource abuse,…

  6. When I Was Hungry. A Hunger Course for High School Students. Teacher's Manual [and] Action Packet.

    Science.gov (United States)

    Bread for the World Educational Fund, Washington, DC.

    Designed to accompany a student activity packet on issues related to world hunger, this teacher's manual provides 12 units of study at the high school level. Materials are presented from a Christian perspective. The following topics are covered in separate chapters: introduction (justice and the right to food), the dimensions and scope of the…

  7. Hungry for housing: waqf real estate development - a social welfare alternative

    Directory of Open Access Journals (Sweden)

    Mohd Ali Siti Nadiah

    2016-01-01

    Full Text Available Islam has outlined 4 important elements to achieve fruitful life in the duniya and the akhirah. A famed hadith of Rasulullah (peace be upon him meaning “Four things that will bring joy to a person, which is (owning a pious woman (wife, a good house (spacious, a good neighbour, and a great vehicle” (Hadith narrated by Ibnu Hibban. It is clear from this hadith that Islam emphasised ownership of a comfortable home. The polemic remains that with skyrocketing housing prices in the market, would the low and middle income groups afford housing that is safe, comfortable and secure? Realising the importance of living in a secure and safe house, this study aims at investigating the possibility of leveraging the upward trend of waqf real estate development in empowering the Muslims’ economy in the country. Towards this end, the authors have conducted a study by collating primary and secondary data obtained from the Penang State Islamic Religious Council (Majlis Agama Islam Pulau Pinang for analysis. Thus the Penang Islamic Council is the study site. Semi structured interviews were conducted with 2 waqf officials who are in charge of coordinating waqf real estate developments in Penang. Based on the study conducted, it was found that Penang State Islamic Religious Council has succeeded in enhancing value added to waqf real estate developments through the implementation of 9 housing project developments using the ijarah concept. The Penang State Islamic Religious Council has enabled the low medium income groups to stay in comfortable and safe housing by utilising such holistic and efficient waqf product developments under shariah guidelines.

  8. A putative octopamine/tyramine receptor mediating appetite in a hungry fly

    Science.gov (United States)

    Ishida, Yuko; Ozaki, Mamiko

    2011-07-01

    In the blowfly Phormia regina, experience of simultaneous feeding with d-limonene exposure inhibits proboscis extension reflex (PER) due to decreased tyramine (TA) titer in the brain. To elucidate the molecular mechanism of TA signaling pathway related to the associated feeding behavior, we cloned cDNA encoding the octopamine/TA receptor (PregOAR/TAR). The deduced protein is composed of 607 amino acid residues and has 7 predicted transmembrane domains. Based on homology and phylogenetic analyses, this protein belongs to the OAR/TAR family. The PregOAR/TAR was mainly expressed in head, with low levels of expression in other tissues at adult stages. Gene expression profile is in agreement with a plethora of functions ascribed to TA in various insect tissues. The immunolabeled cell bodies and processes were localized in the medial protocerebrum, outer layer of lobula, antennal lobe, and subesophageal ganglion. These results suggest that decrease of TA level in the brain likely affects neurons expressing PregOAR/TAR, causing mediation of the sensitivity in the sensillum and/or output of motor neurons for PER.

  9. On feeding those hungry for praise : Person praise backfires in children with low self-esteem

    NARCIS (Netherlands)

    Brummelman, Eddie|info:eu-repo/dai/nl/337238529; Thomaes, Sander|info:eu-repo/dai/nl/303776528; Overbeek, Geertjan|info:eu-repo/dai/nl/25233602X; De Castro, Bram Orobio|info:eu-repo/dai/nl/166985422; Van Den Hout, Marcel A.|info:eu-repo/dai/nl/070445354; Bushman, Brad J.

    2014-01-01

    Child-rearing experts have long believed that praise is an effective means to help children with low self-esteem feel better about themselves. But should one praise these children for who they are, or for how they behave? Study 1 (N = 357) showed that adults are inclined to give children with low

  10. [The art of going hungry. Anorexia in medical texts in the late 19th century].

    Science.gov (United States)

    Diezemann, N

    2000-01-01

    The essay analyzes representations of anorexia in French, English and German medical literature from 1870 to 1900, paying specific attention to rhetorical patterns. Unlike other nervous diseases, anorexia was considered a somatic illness. Rather than subjects, patients were regarded simply as skeletal bodies. Most medical case histories enact the transformation of an emaciated body into a nubile woman-slender, perhaps, but ready for marriage. The patients are described as studious girls who 'devour' literature instead of food. This metaphor is taken from etiology to therapy, when the so-called "Mastkur" in the sanatorium replaces 'enormous' amounts of literature with 'enormous' amounts of food to be eaten.

  11. On feeding those hungry for praise: person praise backfires in children with low self-esteem.

    Science.gov (United States)

    Brummelman, Eddie; Thomaes, Sander; Overbeek, Geertjan; Orobio de Castro, Bram; van den Hout, Marcel A; Bushman, Brad J

    2014-02-01

    Child-rearing experts have long believed that praise is an effective means to help children with low self-esteem feel better about themselves. But should one praise these children for who they are, or for how they behave? Study 1 (N = 357) showed that adults are inclined to give children with low self-esteem more person praise (i.e., praise for personal qualities) but less process praise (i.e., praise for behavior) than they give children with high self-esteem. This inclination may backfire, however. Study 2 (N = 313; M(age) = 10.4 years) showed that person praise, but not process praise, predisposes children, especially those with low self-esteem, to feel ashamed following failure. Consistent with attribution theory, person praise seems to make children attribute failure to the self. Together, these findings suggest that adults, by giving person praise, may foster in children with low self-esteem the very emotional vulnerability they are trying to prevent.

  12. Hungry for love: the influence of self-regulation on infidelity.

    Science.gov (United States)

    Ciarocco, Natalie J; Echevarria, Jessica; Lewandowski, Gary W

    2012-01-01

    The current research examines the effect of self-regulation on the likelihood of committing infidelity. Thirty-two college students in exclusive romantic relationships interacted through a private chat room with an opposite-sex confederate. Prior to this interaction, a food-restriction task depleted half the participants of self-control. As predicted, depleted levels of self-regulation increased the likelihood of infidelity. Specifically, depleted participants were more likely to both accept a coffee date from and supply a personal telephone number to the confederate than non-depleted participants. Weakened self-control may be one potential cause for the levels of infidelity occurring in romantic partnerships today.

  13. Hungry Minds: the Eisenhower Administration and Cultural Assistance in Sub-Saharan Africa (1953-1961)

    NARCIS (Netherlands)

    Gerits, F.P.L.

    2017-01-01

    Dwight Eisenhower did not ignore the call for African independence because of the Soviet threat. Instead cultural assistance—education and information—were employed to foster self-government. This commitment to cultural assistance explains why aid to African countries in real numbers remained low:

  14. European Education Thesaurus: Meeting of the Thesaurus Management Group (Budapest, Hungry, November 6-8, 1996).

    Science.gov (United States)

    EURYDICE European Unit, Brussels (Belgium).

    This report offers the agenda for a meeting in Budapest in November 1996 of the Thesaurus Management Group of the Council of Europe. The report includes a list of participants, a report on previous meetings, information on availability of the 1991 version of the thesaurus and subsequent addenda, information on new versions to be created, and a…

  15. Nuclear vendors see rising prospects for investment in energy-hungry Africa

    Energy Technology Data Exchange (ETDEWEB)

    Shepherd, John [nuclear 24, St. George' s, Redditch (United Kingdom)

    2017-12-15

    The term 'Africa rising' derives from the economic growth witnessed across the continent between 2000 and 2014. However, weakened performance over the past couple of years, particularly in sub-Saharan Africa (SSA), has dented investor confidence and expectations. Nevertheless, the continent remains fertile ground for investment, including nuclear power, and at least two of the world's major nuclear operators and developers - Russia and and China - are stepping up interest in the region.

  16. Libby/Hungry Horse Dams Wildlife Mitigation : Montana Wildlife Habitat Protection : Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Marilyn

    1992-12-01

    The purpose of this project was to develop and obtain information necessary to evaluate and undertake specific wildlife habitat protection/enhancement actions in northwest Montana as outlined in the Columbia River Basin Fish and Wildlife Program. Three waterfowl projects were evaluated between September 1989 and June 1990. Weaver's Slough project involved the proposed acquisition of 200 acres of irrigated farmland and a donated conservation easement on an additional 213 acres. The proposal included enhancement of the agricultural lands by conversion to upland nesting cover. This project was rated the lowest priority based on limited potential for enhancement and no further action was pursued. The Crow Creek Ranch project involved the proposed acquisition of approximately 1830 acres of grazing and dryland farming lands. The intent would be to restore drained potholes and provide adjacent upland nesting cover to increase waterfowl production. This project received the highest rating based on the immediate threat of subdivision, the opportunity to restore degraded wetlands, and the overall benefits to numerous species besides waterfowl. Ducks Unlimited was not able to participate as a cooperator on this project due to the jurisdiction concerns between State and tribal ownership. The USFWS ultimately acquired 1,550 acres of this proposed project. No mitigation funds were used. The Ashley Creek project involved acquisition of 870 acres adjacent to the Smith Lake Waterfowl Production Area. The primary goal was to create approximately 470 acres of wetland habitat with dikes and subimpoundments. This project was rated second in priority due to the lesser threat of loss. A feasibility analysis was completed by Ducks Unlimited based on a concept design. Although adequate water was available for the project, soil testing indicated that the organic soils adjacent to the creek would not support the necessary dikes. The project was determined not feasible for mitigation implementation. Although no waterfowl/wetland projects were implemented using mitigation funds, 1,550 acres were protected based on work done under this project.

  17. Hungry women: sin and rebellion through food and music in the early modern era

    Directory of Open Access Journals (Sweden)

    Gioia Filocamo

    2015-01-01

    Full Text Available Longing for food has always had different implications for men and women: associated with power and strength for men, it tends to have a worrying proximity to sexual pleasure for women. Showing an interesting parallelism throughout the Cinquecento, Italian humanists and teachers insisted on forbidding women music and gluttony. Food and music were both considered dangerous stimulants for the female senses, and every woman was encouraged to consider herself as a kind of food to be offered to the only human beings authorized to feel and satisfy desires: men and babies. Women could properly express themselves only inside monastic circles: the most prolific female composer of the seventeenth century was a nun, as was the first woman who wrote down recipes. Elaborate music and food became the means to maintain a lively relationship with the external world. Moreover, nuns also escaped male control by using the opposite system of affirming themselves through fasting and mortifying the flesh.

  18. Hungry for Love: The Feeding Relationship in the Psychological Development of Young Children

    OpenAIRE

    Slaughter, Charles W; Bryant, Alika Hope

    2004-01-01

    At a time of increasing concern about childhood obesity, health care practitioners can exert pressure on parents and other caregivers to view meals and snacks primarily as opportunities to control children’s caloric intake and thus prevent or control childhood obesity. Yet feeding is about much more than the amount and kinds of food offered: Feeding can have a powerful influence not only on the physical health of children but also on their social and emotional health. The feeding interactions...

  19. Nuclear vendors see rising prospects for investment in energy-hungry Africa

    International Nuclear Information System (INIS)

    Shepherd, John

    2017-01-01

    The term 'Africa rising' derives from the economic growth witnessed across the continent between 2000 and 2014. However, weakened performance over the past couple of years, particularly in sub-Saharan Africa (SSA), has dented investor confidence and expectations. Nevertheless, the continent remains fertile ground for investment, including nuclear power, and at least two of the world's major nuclear operators and developers - Russia and and China - are stepping up interest in the region.

  20. Can Australia Power the Energy-Hungry Asia with Renewable Energy?

    Directory of Open Access Journals (Sweden)

    Ashish Gulagi

    2017-02-01

    Full Text Available The Paris Agreement points out that countries need to shift away from the existing fossil-fuel-based energy system to limit the average temperature rise to 1.5 or 2 °C. A cost-optimal 100% renewable energy based system is simulated for East Asia for the year 2030, covering demand by power, desalination, and industrial gas sectors on an hourly basis for an entire year. East Asia was divided into 20 sub-regions and four different scenarios were set up based on the level of high voltage grid connection, and additional demand sectors: power, desalination, industrial gas, and a renewable-energy-based synthetic natural gas (RE-SNG trading between regions. The integrated RE-SNG scenario gives the lowest cost of electricity (€52/MWh and the lowest total annual cost of the system. Results contradict the notion that long-distance power lines could be beneficial to utilize the abundant solar and wind resources in Australia for East Asia. However, Australia could become a liquefaction hub for exporting RE-SNG to Asia and a 100% renewable energy system could be a reality in East Asia with the cost assumptions used. This may also be more cost-competitive than nuclear and fossil fuel carbon capture and storage alternatives.

  1. Efficient multi-site data movement using constraint programming for data hungry science

    International Nuclear Information System (INIS)

    Zerola, Michal; Sumbera, Michal; Lauret, Jerome; Bartak, Roman

    2010-01-01

    For the past decade, HENP experiments have been heading towards a distributed computing model in an effort to concurrently process tasks over enormous data sets that have been increasing in size as a function of time. In order to optimize all available resources (geographically spread) and minimize the processing time, it is necessary to face also the question of efficient data transfers and placements. A key question is whether the time penalty for moving the data to the computational resources is worth the presumed gain. Onward to the truly distributed task scheduling we present the technique using a Constraint Programming (CP) approach. The CP technique schedules data transfers from multiple resources considering all available paths of diverse characteristic (capacity, sharing and storage) having minimum user's waiting time as an objective. We introduce a model for planning data transfers to a single destination (data transfer) as well as its extension for an optimal data set spreading strategy (data placement). Several enhancements for a solver of the CP model will be shown, leading to a faster schedule computation time using symmetry breaking, branch cutting, well studied principles from job-shop scheduling field and several heuristics. Finally, we will present the design and implementation of a corner-stone application aimed at moving datasets according to the schedule. Results will include comparison of performance and trade-off between CP techniques and a Peer-2-Peer model from simulation framework as well as the real case scenario taken from a practical usage of a CP scheduler.

  2. Hungry today, unhappy tomorrow? Childhood hunger and subjective wellbeing later in life.

    Science.gov (United States)

    Bertoni, Marco

    2015-03-01

    I use anchoring vignettes to show that, on data for eleven European countries, exposure to episodes of hunger in childhood leads people to adopt lower subjective standards to evaluate satisfaction with life in adulthood. I also show that, as a consequence, estimates of the association between childhood starvation and late-life wellbeing that do not allow for reporting heterogeneity are biased towards finding a positive correlation. These results highlight the need to consider rescaling when drawing inference on subjective outcomes. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Data protection legislation: A very hungry caterpillar: The case of mapping data in the European Union

    NARCIS (Netherlands)

    Ploeger, H.D.; van Loenen, Bastiaan; Kulk, Stefan

    2016-01-01

    The European Union's policy on open data aims at generating value through re-use of public sector information, such as mapping data. Open data policies should be applied in full compliance with the principles relating to the protection of personal data of the EU Data Protection Directive. Increased

  4. The Hungry Mind: From the Casa dei Bambini to Cosmic Education

    Science.gov (United States)

    Grazzini, Baiba Krumins

    2016-01-01

    Baiba Krumins Grazzini has generously transformed her lecture, delivered at the AMI-USA Refresher Course in 2014, into a legacy article. This article establishes the role of storytelling in Cosmic Education while capturing both the whole and the detailed parts of Montessori Cosmic Education. Working from the early childhood transition into the…

  5. Hungry earth and vengeful stars: soul loss and identity in the Peruvian Andes.

    Science.gov (United States)

    Greenway, C

    1998-10-01

    This article contributes to the cross-cultural literature on fright sickness and soul loss with an analysis of cases among Quechua indians (runa) in a rural community in the southern Peruvian Andes. One of the aims of this article is to incorporate an emic understanding of the intersection of the cosmological and social landscapes into discussions of Quechua conceptions of health and illness. It outlines Quechua constructions of body, self, and cosmos that are relevant to explaining the concepts of soul/spirit, interior/exterior, and runa/nonruna that are related to soul loss. The illness suffered by victims of fright sickness embodies the Quechua construction of self and is linked not only to broader sociopolitical realities of Peru but also to cosmological beliefs. The diagnosis of spirit loss and fright in this cultural context reveals a crisis of identity: sufferers represent nonruna, or nonhumans. They succumb to fright or soul loss because of an emic concept of vulnerability that transcends the characteristics of gender and age usually associated with soul loss cross-culturally. Treatments, therefore, involve a reaffirmation of ethnic identity and a reintegration of patients into their families in terms of a culturally specific understanding of identity, community, and cosmos. rights reserved

  6. Better Few than Hungry: Flexible Feeding Ecology of Collared Lemurs Eulemur collaris in Littoral Forest Fragments

    Science.gov (United States)

    Donati, Giuseppe; Kesch, Kristina; Ndremifidy, Kelard; Schmidt, Stacey L.; Ramanamanjato, Jean-Baptiste; Borgognini-Tarli, Silvana M.; Ganzhorn, Joerg U.

    2011-01-01

    Background Frugivorous primates are known to encounter many problems to cope with habitat degradation, due to the fluctuating spatial and temporal distribution of their food resources. Since lemur communities evolved strategies to deal with periods of food scarcity, these primates are expected to be naturally adapted to fluctuating ecological conditions and to tolerate a certain degree of habitat changes. However, behavioral and ecological strategies adopted by frugivorous lemurs to survive in secondary habitats have been little investigated. Here, we compared the behavioral ecology of collared lemurs (Eulemur collaris) in a degraded fragment of littoral forest of south-east Madagascar, Mandena, with that of their conspecifics in a more intact habitat, Sainte Luce. Methodology/Principal Findings Lemur groups in Mandena and in Sainte Luce were censused in 2004/2007 and in 2000, respectively. Data were collected via instantaneous sampling on five lemur groups totaling 1,698 observation hours. The Shannon index was used to determine dietary diversity and nutritional analyses were conducted to assess food quality. All feeding trees were identified and measured, and ranging areas determined via the minimum convex polygon. In the degraded area lemurs were able to modify several aspects of their feeding strategies by decreasing group size and by increasing feeding time, ranging areas, and number of feeding trees. The above strategies were apparently able to counteract a clear reduction in both food quality and size of feeding trees. Conclusions/Significance Our findings indicate that collared lemurs in littoral forest fragments modified their behavior to cope with the pressures of fluctuating resource availability. The observed flexibility is likely to be an adaptation to Malagasy rainforests, which are known to undergo periods of fruit scarcity and low productivity. These results should be carefully considered when relocating lemurs or when selecting suitable areas for their conservation. PMID:21625557

  7. Headless, hungry, and unhealthy: a video content analysis of obese persons portrayed in online news.

    Science.gov (United States)

    Puhl, Rebecca M; Peterson, Jamie Lee; DePierre, Jenny A; Luedicke, Joerg

    2013-01-01

    The news media has substantial influence on public perceptions of social and health issues. This study conducted a video content analysis to examine portrayals of obese persons in online news reports about obesity. The authors downloaded online news videos about obesity (N = 371) from 5 major news websites and systematically coded visual portrayals of obese and nonobese adults and youth in these videos. The authors found that 65% of overweight/obese adults and 77% of overweight/obese youth were portrayed in a negative, stigmatizing manner across multiple obesity-related topics covered in online news videos. In particular, overweight/obese individuals were significantly more likely than were nonoverweight individuals to be portrayed as headless, with an unflattering emphasis on isolated body parts, from an unflattering rear view of their excess weight, eating unhealthy foods, engaging in sedentary behavior, and dressed in inappropriately fitting clothing. Nonoverweight individuals were significantly more likely to be portrayed positively. In conclusion, obese children and adults are frequently stigmatized in online news videos about obesity. These findings have important implications for public perceptions of obesity and obese persons and may reinforce negative societal weight bias.

  8. Hungry for success: Urban consumer demand for wild animal products in Vietnam

    OpenAIRE

    Rebecca Drury

    2011-01-01

    Rising urban prosperity is escalating demand for wild animal products in Vietnam. Conservation interventions seek to influence consumer demand, but are based on a limited understanding of consumers and consumption behaviour. This report presents key findings of a structured survey (n=915) and semi-structured interviews (n=78) to investigate the social context of consumption of wild animal-derived products among the population of central Hanoi. Wildmeat is the product most commonly reported co...

  9. Hungry for success: Urban consumer demand for wild animal products in Vietnam

    Directory of Open Access Journals (Sweden)

    Rebecca Drury

    2011-01-01

    Full Text Available Rising urban prosperity is escalating demand for wild animal products in Vietnam. Conservation interventions seek to influence consumer demand, but are based on a limited understanding of consumers and consumption behaviour. This report presents key findings of a structured survey (n=915 and semi-structured interviews (n=78 to investigate the social context of consumption of wild animal-derived products among the population of central Hanoi. Wildmeat is the product most commonly reported consumed-predominantly by successful, high-income, high-status males of all ages and educational levels-and is used as a medium to communicate prestige and obtain social leverage. As Vietnam′s economy grows and its population ages, demand for wildmeat and medicinal products is likely to rise. Given the difficulties of acting on personal rather than collective interests and the symbolic role of wildmeat in an extremely status-conscious society, reducing demand is challenging. Influencing consumer behaviour over the long term requires social marketing expertise and has to be informed by an in-depth understanding, achieved using appropriate methods, of the social drivers of consumer demand for wild animal products. In the meantime, strengthened enforcement is needed to prevent the demand being met from consumers prepared to pay the rising costs of finding the last individuals of a species.

  10. Rapid Coeval Black Hole and Host Galaxy Growth in MRC 1138-262 : The Hungry Spider

    NARCIS (Netherlands)

    Seymour, N.; Altieri, B.; De Breuck, C.; Barthel, P.; Coia, D.; Conversi, L.; Dannerbauer, H.; Dey, A.; Dickinson, M.; Drouart, G.; Galametz, A.; Greve, T. R.; Haas, M.; Hatch, N.; Ibar, E.; Ivison, R.; Jarvis, M.; Kovacs, A.; Kurk, J.; Lehnert, M.; Miley, G.; Nesvadba, N.; Rawlings, J. I.; Rettura, A.; Rottgering, H.; Rocca-Volmerange, B.; Sanchez-Portal, M.; Santos, J. S.; Stern, D.; Stevens, J.; Valtchanov, I.; Vernet, J.; Wylezalek, D.

    2012-01-01

    We present a detailed study of the infrared spectral energy distribution of the high-redshift radio galaxy MRC 1138-26 at z = 2.156, also known as the Spiderweb Galaxy. By combining photometry from Spitzer, Herschel, and LABOCA we fit the rest-frame 5-300 mu m emission using a two-component,

  11. On feeding those hungry for praise: person praise backfires in children with low self-esteem

    NARCIS (Netherlands)

    Brummelman, E.; Thomaes, S.; Overbeek, G.; Orobio de Castro, B.; van den Hout, M.A.; Bushman, B.J.

    2014-01-01

    Child-rearing experts have long believed that praise is an effective means to help children with low self-esteem feel better about themselves. But should one praise these children for who they are, or for how they behave? Study 1 (N = 357) showed that adults are inclined to give children with low

  12. Feeding a Hungry World: Focus on Rice in Asia and the Pacific.

    Science.gov (United States)

    Mukai, Gary; And Others

    This unit introduces students to the diversity of rice culture and rice-based farming systems in Asia and the Pacific. Students examine issues related to the needs of the future global population. Six rice-producing countries are under study: Bangladesh, China, Indonesia, Japan, Philippines, and Thailand. The lessons include: (1) "Rice in…

  13. Climate-smart Kenyan crop hits a setback – hungry birds | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2013-08-08

    Aug 8, 2013 ... KITUI, Kenya (Thomson Reuters Foundation) – Gadam, a fast-maturing, ... with small fish and fish food, but not given adequate knowledge on how to ... with the Collaborative Adaptation Research Initiative in Africa and Asia, ...

  14. Hungry for an intervention? : Adolescents' ratings of acceptability of eating-related intervention strategies

    NARCIS (Netherlands)

    Stok, F Marijn; de Ridder, Denise T D; de Vet, Emely; Nureeva, Liliya; Luszczynska, Aleksandra; Wardle, Jane; Gaspar, Tania; de Wit, John B F

    2016-01-01

    BACKGROUND: Effective interventions promoting healthier eating behavior among adolescents are urgently needed. One factor that has been shown to impact effectiveness is whether the target population accepts the intervention. While previous research has assessed adults' acceptance of eating-related

  15. Hungry for an intervention? Adolescents' ratings of acceptability of eating-related intervention strategies

    NARCIS (Netherlands)

    Stok, F.M.; Ridder, de D.T.D.; Vet, de Emely; Nureeva, Liliya; Luszczynska, Aleksandra; Wardle, Jane; Gaspar, Tania; Wit, de J.B.F.

    2016-01-01

    Background: Effective interventions promoting healthier eating behavior among adolescents are urgently needed. One factor that has been shown to impact effectiveness is whether the target population accepts the intervention. While previous research has assessed adults' acceptance of

  16. Data protection legislation : A very hungry caterpillar. The case of mapping data in the European Union

    NARCIS (Netherlands)

    van Loenen, Bastiaan; Kulk, Stefan; Ploeger, Hendrik

    2016-01-01

    The European Union's policy on open data aims at generating value through re-use of public sector information, such as mapping data. Open data policies should be applied in full compliance with the principles relating to the protection of personal data of the EU Data Protection Directive. Increased

  17. Chinese Outbound Investments in the Food Sector: Hungry for Much More!

    Science.gov (United States)

    Wolff, Lutz-Christian

    2014-01-01

    This article analyses in its first part the almost dramatic increase of Chinese outbound investments in recent years with a special focus on the food industry. The second part outlines China's legal framework that has governed Chinese outbound investments over the past decade. In its main part this article explores recent steps to liberalize China's economy and assesses how the dismantling of existing restrictions will impact on Chinese investments overseas. It forecasts rather wide-ranging consequences for the non-Chinese food industry as food enterprises have become highly-sought after targets of Chinese outbound investment activities.

  18. Species Profile: Flatwoods Salamander (Ambystoma cingulatum) on Military Installations in the Southeastern United States

    National Research Council Canada - National Science Library

    Palis, John

    1997-01-01

    .... Fish and Wildlife Service. The species inhabits the lower Southeastern Coastal Plain from southern South Carolina to northern Florida, and westward through Georgia to extreme southwestern Alabama...

  19. Electrogenic glutamate uptake is a major current carrier in the membrane of axolotl retinal glial cells

    Science.gov (United States)

    Brew, Helen; Attwell, David

    1987-06-01

    Glutamate is taken up avidly by glial cells in the central nervous system1. Glutamate uptake may terminate the transmitter action of glutamate released from neurons1, and keep extracellular glutamate at concentrations below those which are neurotoxic. We report here that glutamate evokes a large inward current in retinal glial cells which have their membrane potential and intracellular ion concentrations controlled by the whole-cell patch-clamp technique2. This current seems to be due to an electrogenic glutamate uptake carrier, which transports at least two sodium ions with every glutamate anion carried into the cell. Glutamate uptake is strongly voltage-dependent, decreasing at depolarized potentials: when fully activated, it contributes almost half of the conductance in the part of the glial cell membrane facing the retinal neurons. The spatial localization, glutamate affinity and magnitude of the uptake are appropriate for terminating the synaptic action of glutamate released from photoreceptors and bipolar cells. These data challenge present explanations of how the b-wave of the electroretinogram is generated, and suggest a mechanism for non-vesicular voltage-dependent release of glutamate from neurons.

  20. Gene expression patterns specific to the regenerating limb of the Mexican axolotl

    Directory of Open Access Journals (Sweden)

    James R. Monaghan

    2012-07-01

    Salamander limb regeneration is dependent upon tissue interactions that are local to the amputation site. Communication among limb epidermis, peripheral nerves, and mesenchyme coordinate cell migration, cell proliferation, and tissue patterning to generate a blastema, which will form missing limb structures. An outstanding question is how cross-talk between these tissues gives rise to the regeneration blastema. To identify genes associated with epidermis-nerve-mesenchymal interactions during limb regeneration, we examined histological and transcriptional changes during the first week following injury in the wound epidermis and subjacent cells between three injury types; 1 a flank wound on the side of the animal that will not regenerate a limb, 2 a denervated limb that will not regenerate a limb, and 3 an innervated limb that will regenerate a limb. Early, histological and transcriptional changes were similar between the injury types, presumably because a common wound-healing program is employed across anatomical locations. However, some transcripts were enriched in limbs compared to the flank and are associated with vertebrate limb development. Many of these genes were activated before blastema outgrowth and expressed in specific tissue types including the epidermis, peripheral nerve, and mesenchyme. We also identified a relatively small group of transcripts that were more highly expressed in innervated limbs versus denervated limbs. These transcripts encode for proteins involved in myelination of peripheral nerves, epidermal cell function, and proliferation of mesenchymal cells. Overall, our study identifies limb-specific and nerve-dependent genes that are upstream of regenerative growth, and thus promising candidates for the regulation of blastema formation.

  1. ISOLATION AND CHARACTERIZATION OF AXOLOTL NPDC-1 AND ITS EFFECTS ON RETINOIC ACID RECEPTOR SIGNALING

    OpenAIRE

    Theodosiou, Maria; Monaghan, James R; Spencer, Michael L; Voss, S Randal; Noonan, Daniel J

    2007-01-01

    Retinoic acid, a key morphogen in early vertebrate development and tissue regeneration, mediates its effects through the binding of receptors that act as ligand-induced transcription factors. These binding events function to recruit an array of transcription co-regulatory proteins to specific gene promoters. One such co-regulatory protein, neuronal proliferation and differentiation control-1 (NPDC-1), is broadly expressed during mammalian development and functions as an in vitro repressor of ...

  2. Precise control of miR-125b levels is required to create a regeneration-permissive environment after spinal cord injury: a cross-species comparison between salamander and rat

    Directory of Open Access Journals (Sweden)

    Juan Felipe Diaz Quiroz

    2014-06-01

    Full Text Available Most spinal cord injuries lead to permanent paralysis in mammals. By contrast, the remarkable regenerative abilities of salamanders enable full functional recovery even from complete spinal cord transections. The molecular differences underlying this evolutionary divergence between mammals and amphibians are poorly understood. We focused on upstream regulators of gene expression as primary entry points into this question. We identified a group of microRNAs (miRNAs that are conserved between the Mexican axolotl salamander (Ambystoma mexicanum and mammals but show marked cross-species differences in regulation patterns following spinal cord injury. We found that precise post-injury levels of one of these miRNAs (miR-125b is essential for functional recovery, and guides correct regeneration of axons through the lesion site in a process involving the direct downstream target Sema4D in axolotls. Translating these results to a mammalian model, we increased miR-125b levels in the rat through mimic treatments following spinal cord transection. These treatments downregulated Sema4D and other glial-scar-related genes, and enhanced the animal’s functional recovery. Our study identifies a key regulatory molecule conserved between salamander and mammal, and shows that the expression of miR-125b and Sema4D must be carefully controlled in the right cells at the correct level to promote regeneration. We also show that these molecular components of the salamander’s regeneration-permissive environment can be experimentally harnessed to improve treatment outcomes for mammalian spinal cord injuries.

  3. Retrotransposon long interspersed nucleotide element-1 (LINE-1) is activated during salamander limb regeneration

    Science.gov (United States)

    Zhu, Wei; Kuo, Dwight; Nathanson, Jason; Satoh, Akira; Pao, Gerald M.; Yeo, Gene W.; Bryant, Susan V.; Voss, S. Randal; Gardiner, David M.; Hunter, Tony

    2012-01-01

    Salamanders possess an extraordinary capacity for tissue and organ regeneration when compared to mammals. In our effort to characterize the unique transcriptional fingerprint emerging during the early phase of salamander limb regeneration, we identified transcriptional activation of some germline-specific genes within the Mexican axolotl (Ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells into a germline-like state. In this work, we focus on one of these genes, the long interspersed nucleotide element-1 (LINE-1) retrotransposon, which is usually active in germ cells and silent in most of the somatic tissues in other organisms. LINE-1 was found to be dramatically upregulated during regeneration. In addition, higher genomic LINE-1 content was also detected in the limb regenerate when compared to that before amputation indicating that LINE-1 retrotransposition is indeed active during regeneration. Active LINE-1 retrotransposition has been suggested to have a potentially deleterious impact on genomic integrity. Silencing of activated LINE-1 by small RNAs has been reported to be part of the machinery aiming to maintain genomic integrity. Indeed, we were able to identify putative LINE-1-related piRNAs in the limb blastema. Transposable element-related piRNAs have been identified frequently in the germline in other organisms. Thus, we present here a scenario in which a unique germline-like state is established during axolotl limb regeneration, and the re-activation of LINE-1 may serve as a marker for cellular dedifferentiation in the early-stage of limb regeneration. PMID:22913491

  4. Microarray and cDNA sequence analysis of transcription during nerve-dependent limb regeneration

    Directory of Open Access Journals (Sweden)

    Bryant Susan V

    2009-01-01

    Full Text Available Abstract Background Microarray analysis and 454 cDNA sequencing were used to investigate a centuries-old problem in regenerative biology: the basis of nerve-dependent limb regeneration in salamanders. Innervated (NR and denervated (DL forelimbs of Mexican axolotls were amputated and transcripts were sampled after 0, 5, and 14 days of regeneration. Results Considerable similarity was observed between NR and DL transcriptional programs at 5 and 14 days post amputation (dpa. Genes with extracellular functions that are critical to wound healing were upregulated while muscle-specific genes were downregulated. Thus, many processes that are regulated during early limb regeneration do not depend upon nerve-derived factors. The majority of the transcriptional differences between NR and DL limbs were correlated with blastema formation; cell numbers increased in NR limbs after 5 dpa and this yielded distinct transcriptional signatures of cell proliferation in NR limbs at 14 dpa. These transcriptional signatures were not observed in DL limbs. Instead, gene expression changes within DL limbs suggest more diverse and protracted wound-healing responses. 454 cDNA sequencing complemented the microarray analysis by providing deeper sampling of transcriptional programs and associated biological processes. Assembly of new 454 cDNA sequences with existing expressed sequence tag (EST contigs from the Ambystoma EST database more than doubled (3935 to 9411 the number of non-redundant human-A. mexicanum orthologous sequences. Conclusion Many new candidate gene sequences were discovered for the first time and these will greatly enable future studies of wound healing, epigenetics, genome stability, and nerve-dependent blastema formation and outgrowth using the axolotl model.

  5. From biomedicine to natural history research: EST resources for ambystomatid salamanders

    Directory of Open Access Journals (Sweden)

    Bryant Susan V

    2004-08-01

    Full Text Available Abstract Background Establishing genomic resources for closely related species will provide comparative insights that are crucial for understanding diversity and variability at multiple levels of biological organization. We developed ESTs for Mexican axolotl (Ambystoma mexicanum and Eastern tiger salamander (A. tigrinum tigrinum, species with deep and diverse research histories. Results Approximately 40,000 quality cDNA sequences were isolated for these species from various tissues, including regenerating limb and tail. These sequences and an existing set of 16,030 cDNA sequences for A. mexicanum were processed to yield 35,413 and 20,599 high quality ESTs for A. mexicanum and A. t. tigrinum, respectively. Because the A. t. tigrinum ESTs were obtained primarily from a normalized library, an approximately equal number of contigs were obtained for each species, with 21,091 unique contigs identified overall. The 10,592 contigs that showed significant similarity to sequences from the human RefSeq database reflected a diverse array of molecular functions and biological processes, with many corresponding to genes expressed during spinal cord injury in rat and fin regeneration in zebrafish. To demonstrate the utility of these EST resources, we searched databases to identify probes for regeneration research, characterized intra- and interspecific nucleotide polymorphism, saturated a human – Ambystoma synteny group with marker loci, and extended PCR primer sets designed for A. mexicanum / A. t. tigrinum orthologues to a related tiger salamander species. Conclusions Our study highlights the value of developing resources in traditional model systems where the likelihood of information transfer to multiple, closely related taxa is high, thus simultaneously enabling both laboratory and natural history research.

  6. From biomedicine to natural history research: EST resources for ambystomatid salamanders

    Science.gov (United States)

    Putta, Srikrishna; Smith, Jeramiah J; Walker, John A; Rondet, Mathieu; Weisrock, David W; Monaghan, James; Samuels, Amy K; Kump, Kevin; King, David C; Maness, Nicholas J; Habermann, Bianca; Tanaka, Elly; Bryant, Susan V; Gardiner, David M; Parichy, David M; Voss, S Randal

    2004-01-01

    Background Establishing genomic resources for closely related species will provide comparative insights that are crucial for understanding diversity and variability at multiple levels of biological organization. We developed ESTs for Mexican axolotl (Ambystoma mexicanum) and Eastern tiger salamander (A. tigrinum tigrinum), species with deep and diverse research histories. Results Approximately 40,000 quality cDNA sequences were isolated for these species from various tissues, including regenerating limb and tail. These sequences and an existing set of 16,030 cDNA sequences for A. mexicanum were processed to yield 35,413 and 20,599 high quality ESTs for A. mexicanum and A. t. tigrinum, respectively. Because the A. t. tigrinum ESTs were obtained primarily from a normalized library, an approximately equal number of contigs were obtained for each species, with 21,091 unique contigs identified overall. The 10,592 contigs that showed significant similarity to sequences from the human RefSeq database reflected a diverse array of molecular functions and biological processes, with many corresponding to genes expressed during spinal cord injury in rat and fin regeneration in zebrafish. To demonstrate the utility of these EST resources, we searched databases to identify probes for regeneration research, characterized intra- and interspecific nucleotide polymorphism, saturated a human – Ambystoma synteny group with marker loci, and extended PCR primer sets designed for A. mexicanum / A. t. tigrinum orthologues to a related tiger salamander species. Conclusions Our study highlights the value of developing resources in traditional model systems where the likelihood of information transfer to multiple, closely related taxa is high, thus simultaneously enabling both laboratory and natural history research. PMID:15310388

  7. Multi-scale finite element modeling allows the mechanics of amphibian neurulation to be elucidated

    International Nuclear Information System (INIS)

    Chen Xiaoguang; Wayne Brodland, G

    2008-01-01

    The novel multi-scale computational approach introduced here makes possible a new means for testing hypotheses about the forces that drive specific morphogenetic movements. A 3D model based on this approach is used to investigate neurulation in the axolotl (Ambystoma mexicanum), a type of amphibian. The model is based on geometric data from 3D surface reconstructions of live embryos and from serial sections. Tissue properties are described by a system of cell-based constitutive equations, and parameters in the equations are determined from physical tests. The model includes the effects of Shroom-activated neural ridge reshaping and lamellipodium-driven convergent extension. A typical whole-embryo model consists of 10 239 elements and to run its 100 incremental time steps requires 2 days. The model shows that a normal phenotype does not result if lamellipodium forces are uniform across the width of the neural plate; but it can result if the lamellipodium forces decrease from a maximum value at the mid-sagittal plane to zero at the plate edge. Even the seemingly simple motions of neurulation are found to contain important features that would remain hidden, they were not studied using an advanced computational model. The present model operates in a setting where data are extremely sparse and an important outcome of the study is a better understanding of the role of computational models in such environments

  8. Multi-scale finite element modeling allows the mechanics of amphibian neurulation to be elucidated

    Science.gov (United States)

    Chen, Xiaoguang; Brodland, G. Wayne

    2008-03-01

    The novel multi-scale computational approach introduced here makes possible a new means for testing hypotheses about the forces that drive specific morphogenetic movements. A 3D model based on this approach is used to investigate neurulation in the axolotl (Ambystoma mexicanum), a type of amphibian. The model is based on geometric data from 3D surface reconstructions of live embryos and from serial sections. Tissue properties are described by a system of cell-based constitutive equations, and parameters in the equations are determined from physical tests. The model includes the effects of Shroom-activated neural ridge reshaping and lamellipodium-driven convergent extension. A typical whole-embryo model consists of 10 239 elements and to run its 100 incremental time steps requires 2 days. The model shows that a normal phenotype does not result if lamellipodium forces are uniform across the width of the neural plate; but it can result if the lamellipodium forces decrease from a maximum value at the mid-sagittal plane to zero at the plate edge. Even the seemingly simple motions of neurulation are found to contain important features that would remain hidden, they were not studied using an advanced computational model. The present model operates in a setting where data are extremely sparse and an important outcome of the study is a better understanding of the role of computational models in such environments.

  9. Hungry Unlike the Wolf: Ecology, Posthumanism, Narratology in Fred Vargas’s Seeking Whom He May Devour

    Directory of Open Access Journals (Sweden)

    John Parham

    2012-01-01

    Full Text Available This paper examines posthumanism as a philosophical position equipped to inform ecocriticism and the potential of popular fiction to articulate ecological complexity. Posthumanism will be reappraised as a dialectical model that decentres the human in relation to ‘evolutionary, ecological, or technological coordinates’ (Wolfe 2010: xvi while nevertheless retaining a sense of the integrity of, and boundaries between, human and nonhuman species or phenomena. It will be argued that a novelistic emphasis on human being, agency, and action, coupled with devices of genre, plot, atnd narrative – are consistent with the process of human self‐examinaion engendered by posthumanism. The essay will, thereafter, illustrate and examine this approach through the French crime writer Fred Vargas’s1999 novel Seeking Whom He May Devour. Identifying two human protagonists – the Canadian conservationist Johnstone and his girlfriend Camille – an initial decentring of the human subject will be examined in relation to two equivalent, nonhuman protagonists, the French Alps and the wolf. Utilising newspaper interviews that highlight Vargas’s own posthumanist perspective (grounded in her profession as an archaeologist, I will examine a how the novel explores appropriate relationships between human and nonhuman animals; b how Vargas utilises both the generic features of the crime novel – e.g. the resolution of a ‘crime’ – and the subtle narrative manipulations of character focalisation to construct (via the preferred ‘point of iew’ offered by Camille a posthumanist position on human/animal relations which argas explicitly opposes to the inhumanism represented by Johnstone.

  10. Identifying and Using Picture Books with Quality Mathematical Content: Moving beyond "Counting on Frank" and "The Very Hungry Caterpillar"

    Science.gov (United States)

    Marston, Jennie

    2014-01-01

    This article by Jennie Marston provides a framework to assist you in selecting appropriate picture books to present mathematical content. Jennie demonstrates the framework by applying three specific examples of picture books to the framework along with examples of activities.

  11. "I get hungry all the time": experiences of poverty and pregnancy in an urban healthcare setting in South Africa.

    Science.gov (United States)

    Scorgie, Fiona; Blaauw, Duane; Dooms, Tessa; Coovadia, Ashraf; Black, Vivian; Chersich, Matthew

    2015-08-25

    For pregnancy to result in a healthy mother and infant, women require adequate nutrition and to be able to access antenatal care, both of which require finances. While most women working in the formal sector in South Africa obtain some form of maternity leave, unemployed women receive no such support. Additional interventions in the form of expanded social assistance to vulnerable pregnant women are needed. To help inform such an approach, we undertook a series of qualitative interviews with low-income pregnant women in Johannesburg. Qualitative, in-depth interviews were held with 22 pregnant women at a public sector antenatal clinic in Johannesburg in 2011 to gather data on their greatest needs and priorities during pregnancy, their access to financial resources to meet these needs, and the overall experience of poverty while pregnant. A total of 22 women were interviewed, 5 of whom were primagravid. One woman was in the first trimester of pregnancy, while nine were almost full-term. All but one of the pregnancies were unplanned. Most participants (15/22) were unemployed, two were employed and on paid maternity leave, and the remaining five doing casual, part-time work. In most cases, pregnancy reduced participants' earning potential and heightened reliance on their partners. Women not living with the father of their children generally received erratic financial support from them. The highest monthly expenses mentioned were food, accommodation and transport costs, and shortfalls in all three were reportedly common. Some participants described insufficient food in the household, and expressed concern about whether they were meeting the additional dietary requirements of pregnancy. Preparing for the arrival of a new baby was also a considerable source of anxiety, and was prioritized even above meeting women's own basic needs. Though pregnancy is a normal life occurrence, it has the potential to further marginalise women and children living in already vulnerable households. Extending the Child Support Grant to include the period of pregnancy would not only serve to acknowledge and address the particular challenges faced by poor women, but also go some way to securing the health of newborn children and future generations.

  12. Effects of pH on embryo tolerance and adult behavior in the tiger salamander, Ambystoma tigrinum tigrinum

    Energy Technology Data Exchange (ETDEWEB)

    Whiteman, H H; Howard, R D; Whitten, K A [Purdue Univ., Lafayette, IN (United States). Dept. of Biological Sciences

    1995-08-01

    Adult discrimination ability and embryo performance was examined under different pH conditions in the eastern tiger salamander. Individuals from three populations were collected in habitats that differed naturally in pH. Two pH treatments were used to determine adult pH discrimination ability, and eight pH treatments to evaluate embryo performance. Results suggested that the pH of the source-population habitat could influence breeding-habitat discrimination by adults. Decreasing pH produced similar patterns of lethal and sublethal effects on embryos from the three populations, with reduced performance at low pH. The pH at which 50% mortality occurs was estimated at 4.2, suggesting that tiger salamanders were relatively acid tolerant. The study suggested that adult behavior patterns could influence the success of population reintroductions to previously acidified areas. 78 refs., 2 tabs., 4 figs.

  13. INTERACTIONS BETWEEN BRANCHIATE MOLE SALAMANDERS (AMBYSTOMA TALPOIDEUM) AND LESSER SIRENS (SIREN INTERMEDIA): ASYMMETRICAL COMPETITION AND INTRAGUILD PREDATION. (R825795)

    Science.gov (United States)

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

  14. Multiplicity of Buc copies in Atlantic salmon contrasts with loss of the germ cell determinant in primates, rodents and axolotl

    OpenAIRE

    Skugor, Adrijana; Tveiten, Helge; Johnsen, Hanne; Andersen, Øivind

    2016-01-01

    Background The primordial germ cells (PGCs) giving rise to gametes are determined by two different mechanisms in vertebrates. While the germ cell fate in mammals and salamanders is induced by zygotic signals, maternally delivered germ cell determinants specify the PGCs in birds, frogs and teleost fish. Assembly of the germ plasm in the oocyte is organized by the single Buc in zebrafish, named Velo1 in Xenopus, and by Oskar in Drosophila. Secondary loss of oskar in several insect lineages coin...

  15. Inhibition of the Processes of Growth and Differentiation in the Embryonic Development of the Axolotl (Ambystma mexicanum)

    NARCIS (Netherlands)

    Stolk, Anth.

    1954-01-01

    The problem of the retardation of the processes of growth and differentiation is certainly as important as the processes of growth and differentiation themselves. It is striking, therefore, that whereas the analysis of growth has been carried out for a considerable period of time already, the

  16. "I'm an Ogre so I'm Very Hungry!" "I'm Assistant Ogre": The Social Function of Sibling Imitation in Early Childhood

    Science.gov (United States)

    Howe, Nina; Rosciszewska, Joanna; Persram, Ryan J.

    2018-01-01

    Siblings' imitative behaviors were investigated in 39 middle-class dyads during six 90-min home sessions at both Time 1 (M age: older sibling = 4.4 years; younger sibling = 2.4 years) and Time 2 (2 years later). Although younger siblings imitated most often at T1 and T2, older siblings' imitation increased proportionally over time in comparison to…

  17. Hungry to learn: the prevalence and effects of food insecurity on health behaviors and outcomes over time among a diverse sample of university freshmen.

    Science.gov (United States)

    Bruening, Meg; van Woerden, Irene; Todd, Michael; Laska, Melissa N

    2018-01-18

    To examine longitudinal associations between food insecurity (FI) and health behaviors/outcomes among a diverse sample of university freshmen. Freshman students (n = 1138; 65% female; 49% non-white) participating in the Social impact of Physical Activity and nutRition in College study completed surveys on health behaviors and had height/weight measured up to 4 times (T1-T4) in Arizona during 2015-2016. Structural equation models were estimated to determine if, after adjusting for covariates, FI predicted concurrent behaviors/outcomes and subsequent behaviors/outcomes. Analyses reported here were conducted in 2017. The prevalence of FI was significantly higher at the end of each semester (35% and 36%, respectively) than at the start of the year (28%). Longitudinally, FI was not related to any health behaviors/outcomes at future time points. However, FI was significantly and inversely associated with concurrent breakfast consumption on most days of the week (OR = 0.67, 99% CI = 0.46, 0.99), daily evening meal consumption (OR = 0.55, 99% CI = 0.36, 0.86) healthy eating habits on campus (OR = 0.68, 99% CI = 0.46, 1.00), healthy physical activity habits on campus (OR = 0.66, 99% CI = 0.44, 1.00), and positively related to the likelihood of experiencing stress (OR = 1.69, 99% CI = 1.16, 2.46) and depressed mood (OR = 1.98, 99% CI = 1.34, 2.91). Compared with US prevalence rates, the sample FI prevalence was high. FI was related to poorer eating patterns, physical activity behaviors, and mental health, even after adjusting for prior levels of behavior.

  18. The interface theory of perception leaves me hungry for more: Commentary on Hoffman, Singh, and Prakash, "The interface theory of perception".

    Science.gov (United States)

    Schlesinger, Matthew

    2015-12-01

    The interface theory offers a rich blend of logic and mathematical modeling with a dash of evolutionary story-telling, leading to the conclusion that perceptual experience and physical reality are only loosely related. Is the theory convincing? I would have to say "almost"; although it certainly has many elements working in its favor, ultimately, I also found that some important questions were ignored or left unanswered (e.g., a more fully articulated account of how evolutionary mechanisms operate on perception). I am quite optimistic that the next iteration of the theory will be able to address these issues.

  19. Reconciling Self-Regard, Concern for Others, and a Passion for Teaching Music: Lessons from the Hunger Artist and the Hungry Ghost

    Science.gov (United States)

    Morton, Charlene A.

    2012-01-01

    In his book, Chris Higgins acknowledges the challenges of teaching associated with heavy workloads, increasing responsibilities, and often diminishing respect from the very public institutions that teachers serve. However, his purpose is not to deplore the external conditions of teaching but to raise concerns about its service culture. He argues…

  20. A new and improved algorithm for the quantification of chromatin condensation from microscopic data shows decreased chromatin condensation in regenerating axolotl limb cells.

    Directory of Open Access Journals (Sweden)

    Julian Sosnik

    Full Text Available The nuclear landscape plays an important role in the regulation of tissue and positional specific genes in embryonic and developing cells. Changes in this landscape can be dynamic, and are associated with the differentiation of cells during embryogenesis, and the de-differentiation of cells during induced pluripotent stem cell (iPSC formation and in many cancers. However, tools to quantitatively characterize these changes are limited, especially in the in vivo context, where numerous tissue types are present and cells are arranged in multiple layers. Previous tools have been optimized for the monolayer nature of cultured cells. Therefore, we present a new algorithm to quantify the condensation of chromatin in two in vivo systems. We first developed this algorithm to quantify changes in chromatin compaction and validated it in differentiating spermatids in zebrafish testes. Our algorithm successfully detected the typical increase in chromatin compaction as these cells differentiate. We then employed the algorithm to quantify the changes that occur in amphibian limb cells as they participate in a regenerative response. We observed that the chromatin in the limb cells de-compacts as they contribute to the regenerating organ. We present this new tool as an open sourced software that can be readily accessed and optimized to quantify chromatin compaction in complex multi-layered samples.

  1. Dicty_cDB: Contig-U11847-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 00512_699( AE000512 |pid:none) Thermotoga maritima MSB8, comple... 42 0.065 JC2551( JC2551 ) tropomyosin alpha chain - axolotl...AltName: Full=Myosin heavy chai... 42 0.11 JC6199( JC6199 ) alpha-tropomyosin S-1 - axolotl &U33450_1(U33450

  2. Electrically Mediated Trauma Repair

    Science.gov (United States)

    1994-07-07

    potential (TEP) (Johnston and Hoshiko, 1971; Rick et al., 1988; Shi and Borgens, 1994). In the axolotl neurulae, a gradient of 10 - 20 mV/mm is...reach 60-80 mV/mm. A more shallow voltage gradient is observed in the transverse plane of axolotl neurulae associated with mirror image outwardly

  3. Australia's uranium - greenhouse friendly fuel for an energy hungry world: a case study into the strategic importance of Australia's uranium resources for the inquiry into developing Australia's non-fossil fuel energy industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-11-15

    The terms of reference for the case study were to inquire into and report on the strategic importance of Australia's uranium resources. The Committee was asked to give particular attention to the: global demand for Australia's uranium resources and associated supply issues; potential implications for global greenhouse emission reductions from the further development and export of Australia's uranium resources; and the current regulatory environment of the uranium mining sector. The Committee indicated in its letters inviting submissions that it would also welcome comments in relation to six additional issues, relating to: whole of life cycle waste management; adequacy of social impact assessment, consultation and approval processes with traditional owners; health risks to workers and to the public from exposure to radiation; adequacy of regulation of uranium mining by the Commonwealth; the extent of federal subsidies and other mechanisms to facilitate uranium mining; and the effectiveness of safeguards regimes in addressing proliferation. These matters are addressed in the Committee's report, which consists of 12 chapters. The contents, findings and recommendations of each chapter are summarised as follows. The Committee's conclusions and recommendations are also summarised in a key messages section at the beginning of each chapter and in the conclusions section at the end of each chapter.

  4. Australia's uranium - greenhouse friendly fuel for an energy hungry world: a case study into the strategic importance of Australia's uranium resources for the inquiry into developing Australia's non-fossil fuel energy industry

    International Nuclear Information System (INIS)

    2006-11-01

    The terms of reference for the case study were to inquire into and report on the strategic importance of Australia's uranium resources. The Committee was asked to give particular attention to the: global demand for Australia's uranium resources and associated supply issues; potential implications for global greenhouse emission reductions from the further development and export of Australia's uranium resources; and the current regulatory environment of the uranium mining sector. The Committee indicated in its letters inviting submissions that it would also welcome comments in relation to six additional issues, relating to: whole of life cycle waste management; adequacy of social impact assessment, consultation and approval processes with traditional owners; health risks to workers and to the public from exposure to radiation; adequacy of regulation of uranium mining by the Commonwealth; the extent of federal subsidies and other mechanisms to facilitate uranium mining; and the effectiveness of safeguards regimes in addressing proliferation. These matters are addressed in the Committee's report, which consists of 12 chapters. The contents, findings and recommendations of each chapter are summarised as follows. The Committee's conclusions and recommendations are also summarised in a key messages section at the beginning of each chapter and in the conclusions section at the end of each chapter

  5. A Formal Approach to Discourse Anaphora

    Science.gov (United States)

    1978-05-01

    was given a nut by Wendy, and Druce did 0 too. 0 = ? 41. The aardvark was given two peanuts for its birthday, and the axolotl was 0 too. 0...given two peanuts for its birthday 42. Wendy avoidf the aardvark, and the axolotl was 0 too. 0 = 7 In the case of multiple passives (such as are...the axolotl was 0 too. 0 = given an apple 45. Bert is a super dentist and his father was 0 too. 0 = (be) a super dentist Moreover, it appeals to me

  6. Ecological Risk Assessment of Perchlorate in Avian Species, Rodents, Amphibians and Fish

    Science.gov (United States)

    2003-04-01

    http://www .indiana.edu/- axolotl ). 10.0 JUSTIFICATION OF TEST SYSTEM Perchlorate occurs in ground and surface waters in 44 states in the USA... axolotl ). * Sequentially numbered in order of the date that the change is effective Dept. of Biological Sciences (DBS) Box 43131 Lubbock, TX 79409...KCl, 0.025 giL; CaCh2 H20, 0.65 g/L; MgS04·7H20, 0.1 giL (http://www.indiana.edu/~ axolotl ). *Sequentially numbered in order of the date that the

  7. SPATIALLY AUTOCORRELATED DEMOGRAPHY AND INTERPOND MIGRATION IN THE CALIFORNIA TIGER SALAMANDER (AMBYSTOME CALIFORNIENSE)

    Science.gov (United States)

    We investigated the metapopulation structure of the California tiger salamander (Ambystoma californiense) using a combination of indirect and direct methods to evaluate two key requirements of modern metapopulation models: 1) that patches support somewhat independent populations ...

  8. Weight gain after quitting smoking: What to do

    Science.gov (United States)

    ... ahead to a roast chicken with vegetables for dinner. Never let yourself get too hungry. A little hunger is a good thing, but if you are so hungry that you have to eat right away, you are more likely to reach ...

  9. Contextual Modulation of Reading Rate for Direct versus Indirect Speech Quotations

    Science.gov (United States)

    Yao, Bo; Scheepers, Christoph

    2011-01-01

    In human communication, direct speech (e.g., "Mary said: "I'm hungry"") is perceived to be more vivid than indirect speech (e.g., "Mary said [that] she was hungry"). However, the processing consequences of this distinction are largely unclear. In two experiments, participants were asked to either orally (Experiment 1) or silently (Experiment 2,…

  10. Senescence gives insights into the morphogenetic evolution of anamniotes

    Directory of Open Access Journals (Sweden)

    Éric Villiard

    2017-06-01

    Full Text Available Senescence represents a mechanism to avoid undesired cell proliferation that plays a role in tumor suppression, wound healing and embryonic development. In order to gain insight on the evolution of senescence, we looked at its presence in developing axolotls (urodele amphibians and in zebrafish (teleost fish, which are both anamniotes. Our data indicate that cellular senescence is present in various developing structures in axolotls (pronephros, olfactory epithelium of nerve fascicles, lateral organs, gums and in zebrafish (epithelium of the yolk sac and in the lower part of the gut. Senescence was particularly associated with transient structures (pronephros in axolotls and yolk sac in zebrafish suggesting that it may play a role in the elimination of these tissues. Our data supports the notion that cellular senescence evolved early in vertebrate evolution to influence embryonic development.

  11. Urodele p53 tolerates amino acid changes found in p53 variants linked to human cancer

    Directory of Open Access Journals (Sweden)

    Villiard Éric

    2007-09-01

    Full Text Available Abstract Background Urodele amphibians like the axolotl are unique among vertebrates in their ability to regenerate and their resistance to develop cancers. It is unknown whether these traits are linked at the molecular level. Results Blocking p53 signaling in axolotls using the p53 inhibitor, pifithrin-α, inhibited limb regeneration and the expression of p53 target genes such as Mdm2 and Gadd45, suggesting a link between tumor suppression and regeneration. To understand this relationship we cloned the p53 gene from axolotl. When comparing its sequence with p53 from other organisms, and more specifically human we observed multiple amino acids changes found in human tumors. Phylogenetic analysis of p53 protein sequences from various species is in general agreement with standard vertebrate phylogeny; however, both mice-like rodents and teleost fishes are fast evolving. This leads to long branch attraction resulting in an artefactual basal emergence of these groups in the phylogenetic tree. It is tempting to assume a correlation between certain life style traits (e.g. lifespan and the evolutionary rate of the corresponding p53 sequences. Functional assays of the axolotl p53 in human or axolotl cells using p53 promoter reporters demonstrated a temperature sensitivity (ts, which was further confirmed by performing colony assays at 37°C. In addition, axolotl p53 was capable of efficient transactivation at the Hmd2 promoter but has moderate activity at the p21 promoter. Endogenous axolotl p53 was activated following UV irradiation (100 j/m2 or treatment with an alkylating agent as measured using serine 15 phosphorylation and the expression of the endogenous p53 target Gadd45. Conclusion Urodele p53 may play a role in regeneration and has evolved to contain multiple amino acid changes predicted to render the human protein defective in tumor suppression. Some of these mutations were probably selected to maintain p53 activity at low temperature. However

  12. The MHC molecules of nonmammalian vertebrates

    DEFF Research Database (Denmark)

    Kaufman, J; Skjoedt, K; Salomonsen, J

    1990-01-01

    class II distribution. The axolotl has a very poor immune response (as though there are no helper T cells), a wide class II distribution and, for most animals, no cell surface class I molecule. It would be enlightening to understand both the mechanisms for the regulation of the MHC molecules during...

  13. Visualisation of animal anatomy using MRI and CT

    DEFF Research Database (Denmark)

    Lauridsen, Henrik; Hansen, Kasper; Pedersen, Michael

    imaging (MRI) and CT. Various species (tarantula, horseshoe crab, carp, haddock, lungfish, axolotl) were subjected to multi-slice MRI and CT protocols to produce 2D images of body slices, followed by volume rendering producing 3D digital models of animal anatomy with applications for visualising specific...

  14. Development and regulation of response properties in spinal cord motoneurons

    DEFF Research Database (Denmark)

    Perrier, J F; Hounsgaard, J

    2000-01-01

    vertebrates in terms of both phylogeny and ontogeny. Spinal motoneurons in adults are remarkably similar in many respects ranging from the resting membrane potential to pacemaker properties. Apart from the axolotls, spinal motoneurons from all species investigated have latent intrinsic response properties...

  15. HBR's 10 must reads: the essentials

    National Research Council Canada - National Science Library

    2011-01-01

    .... That's what makes this book a "must read." These are 10 seminal articles by management's most influential experts, on topics of perennial concern to ambitious managers and leaders hungry for inspiration--and ready to run with big ideas...

  16. N•tuu,lloelt,·e

    African Journals Online (AJOL)

    . Lycaon pictus refers to the black, white and ... animals, with a remarkable degree of social organisa- tion. Young animals were favoured by the pack, and obviously hungry adults that had successfully run down. E. E. WITH A DIFFERENCE!

  17. Genetics Home Reference: proopiomelanocortin deficiency

    Science.gov (United States)

    ... are constantly hungry, which leads to excessive feeding (hyperphagia). The babies continuously gain weight and are severely ... brain dysregulates the body's energy balance, leading to overeating and severe obesity. POMC deficiency is a rare ...

  18. An American Paradox: Hunger in an Affluent Society

    Science.gov (United States)

    McGovern, George S.

    1974-01-01

    Nutritionally vulnerable mothers and children, American Indians and Alaskan Natives, migrant laborers, and the elderly are described as the hungry in America. Additional and more effective government food programs are proposed as the solution. (DE)

  19. Search Results | Page 4 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Results 31 - 40 of 59 ... The mission of the Caribbean Policy Research Institute (CaPRI) is to create ... Hungry Cities Initiative: Informality, Inclusive Growth, and Food Security in ... Opportunities in CARICOM Migration : Brain Circulation, Diasporic ...

  20. Variations of blood glucose in cancer patients during chemotherapy

    African Journals Online (AJOL)

    2016-05-23

    May 23, 2016 ... Purpose: The aim of this study was to analyze the blood glucose (BG) variations in cancer patients .... cancer, brain tumor, cervical cancer, and leukemia were the ... excess glucose supply for these glucose‑hungry cells and it.

  1. Hunger and Malnutrition

    Science.gov (United States)

    ... Videos for Educators Search English Español Hunger and Malnutrition KidsHealth / For Parents / Hunger and Malnutrition What's in ... to meet their needs. What Are Hunger and Malnutrition? Everyone feels hungry at times. Hunger is the ...

  2. HEAD AND NECK SURGERY

    African Journals Online (AJOL)

    +/-symptoms and signs), intravenous calcium gluconate and oral calcium lactate is .... facilitated by surgical stress, Vitamin D deficiency and hungry .... recurrence after thyroid surgery, excluding cancer. Chirurgie. ... Crea C, Alesina P, et al.

  3. Beta Cell Breakthroughs

    Science.gov (United States)

    ... Terms Research & News Recipes & Food Recipe Finder The Healthy Kitchen What Can I Eat? Main Dishes Salads & Sandwiches Breakfast Snacks Sides Dessert I'm Hungry! Body & Mind Well-Being Fitness Weight Loss Blood Glucose & Medications ...

  4. Publications | Page 93 | IDRC - International Development Research ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Results 921 - 930 of 6341 ... Visit the IDRC Digital Library now. ... As governments and businesses around the world struggle to guarantee the safety of their ... Going West: Why the Canadian Prairies might hold the key to feeding a hungry world.

  5. Animal vaccines key to poor farm families' health and prosperity in ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2013-10-29

    Oct 29, 2013 ... ... change, the grim reality is that today “about a billion people go to bed hungry every night. ... How new animal vaccines could keep more African farmers in business ... Building lasting solutions to reduce global hunger.

  6. Search Results | Page 10 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Results 91 - 100 of 162 ... Hungry Cities Initiative: Informality, Inclusive Growth, and Food Security in Cities of the Global South. As urban populations grow in developing countries, promoting inclusive growth that ensures food security for all is critical. Project.

  7. Northwest Montana Wildlife Mitigation Habitat Protection : Advance Design : Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Marilyn A.

    1993-02-01

    This report summarizes the habitat protection process developed to mitigate for certain wildlife and wildlife habitat losses due to construction of Hungry Horse and Libby dams in northwestern Montana.

  8. Pop / Mart Kuldkepp

    Index Scriptorium Estoniae

    Kuldkepp, Mart

    2008-01-01

    Heliplaatidest: Me, Myself and I "Aastaajad", Madonna "Hard Candy", Kathryn Williams and Neill MacColl "Two", Tindersticks "The Hungry Saw", Joy Division "The Best of Joy Divison", Quiet Village "Silent Movie"

  9. Space-Qualifiable Digital Radar Transceiver, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Historically, radar systems have tended to be either large, complex, power-hungry, purpose-built systems, or extremely simple systems of limited capability. More...

  10. Adaptive bio-inspired navigation for planetary exploration, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Exploration of planetary environments with current robotic technologies relies on human control and power-hungry active sensors to perform even the most elementary...

  11. Food Security in Azerbaijan

    Institute of Scientific and Technical Information of China (English)

    Kamran Ismayilov

    2009-01-01

    @@ In the 21st century the society got some achievements in technological,education,economic,social-political,cultural and etc.sectors.But society couldn't solve fully the food security problem yet.According to the information given by FAO if in 1970 there were 400 billion hungry people in the world,in 2008 the number of hungry people was doubled and increased to 800 billion people.

  12. Lifelong Brain Health is a Lifelong Challenge: From Evolutionary Principles to Empirical Evidence

    OpenAIRE

    Mattson, Mark P.

    2015-01-01

    Although the human brain is exceptional in size and information processing capabilities, it is similar to other mammals with regards to the factors that promote its optimal performance. Three such factors are the challenges of physical exercise, food deprivation/fasting, and social/intellectual engagement. Because it evolved, in part, for success in seeking and acquiring food, the brain functions best when the individual is hungry and physically active, as typified by the hungry lion stalking...

  13. The Analysis of Service Quality, Innovation, and Corporate Image on Customer Loyalty of Ragey Von Von Restaurant

    OpenAIRE

    Mongdong, Meidy Angel

    2015-01-01

    People always get hungry so they need food and people find themselves hungry with no time to cook, so they eat out. That€™s why booming the restaurant industry. The restaurant business in North Sulawesi especially in Tomohon have been growing rapidly, particulary minahasa restaurant that selling typical local food Tomohon or Manado because the majority is Christian people therefore many restaurant selling Minahasa food. Service quality, innovation and corporate image is very supportive of cus...

  14. Journal of Genetics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics. ARMANDO SUNNY. Articles written in Journal of Genetics. Volume 96 Issue 6 December 2017 pp 873-883 RESEARCH ARTICLE. Genetic variability and structure of an isolated population of Ambystoma altamirani , a mole salamander that lives in the mountains of one of the largest ...

  15. Environmental Assessment for Conversion of the Existing Aero Club Runway to Emergency Helipad for David Grant Medical Center Travis Air Force Base, Fairfield, California

    Science.gov (United States)

    2010-07-01

    FT Potential Ambystoma californiense California tiger salamander FT Known Branchinecta conservatio Conservancy fairy shrimp FE Potential Elaphrus...elderberry longhorn beetle FT Potential Branchinecta lynchi Vernal pool fairy shrimp FT Known Lepidurus packardi Vernal pool tadpole shrimp FE...Area. During 2008 vernal pool invertebrate monitoring, CTS larvae were discovered in the northeastern part of Travis AFB, in the Castle Terrace

  16. Environmental Assessment 819th Red Horse Five Year Plan, Malmstrom Air Force Base, Montana

    Science.gov (United States)

    2007-08-07

    the health of sensitive populations such as people with asthma , children, and the 23 elderly. Secondary standards define levels of air quality...pipiens), the tiger salamander 38 (Ambystoma tigrinum), and painted turtle (Chrysemys picta) (MTNHP 2006a). Other species 39 that may live in the

  17. Assessing Projection Bias in Consumers' Food Preferences.

    Directory of Open Access Journals (Sweden)

    Tiziana de-Magistris

    Full Text Available The aim of this study is to test whether projection bias exists in consumers' purchasing decisions for food products. To achieve our aim, we used a non-hypothetical experiment (i.e., experimental auction, where hungry and non-hungry participants were incentivized to reveal their willingness to pay (WTP. The results confirm the existence of projection bias when consumers made their decisions on food products. In particular, projection bias existed because currently hungry participants were willing to pay a higher price premium for cheeses than satiated ones, both in hungry and satiated future states. Moreover, participants overvalued the food product more when they were delivered in the future hungry condition than in the satiated one. Our study provides clear, quantitative and meaningful evidence of projection bias because our findings are based on economic valuation of food preferences. Indeed, the strength of this study is that findings are expressed in terms of willingness to pay which is an interpretable amount of money.

  18. TRACKING STEM CELLS IN AN INHERENTLY REGENRATIVE ENVIRONMENT

    DEFF Research Database (Denmark)

    Lauridsen, Henrik; Foldager, Casper Bindzus; Hagensen, Mette

    2012-01-01

    of such therapies. The objective of this study was to non-invasively evaluate regeneration over time in a truly regenerative process, the regeneration of an axolotl limb, employing superparamagnetic iron oxide particles (SPIO) contrast agents for stem cell tracking in MRI. Materials and Methods: Amputation of one...... in conjugation with the transfection agent poly-L-lysin (PLL) was tested on cultures of axolotl blastema cells from 7 animals in vitro. PicoGreen-DNA quantification following 3 weeks of culturing was performed to quantify cell viability. MRI-tracking of SPIO labelled blastema cells in the regenerating limb of 5....... Results: SPIO labelling with neither VSOP-C200, Resovist nor Resovist/PLL had any significant effect on blastema cell viability in vitro. Labelled tissue was clearly detectable in vivo 49 days after amputation using MRI (Fig. 1) and a significant decline in signal intensity of labelled limbs versus sham...

  19. Hibridez y metamorfosis en Juan Villoro: el universo mágico-mitológico del ajolote

    Directory of Open Access Journals (Sweden)

    An Van Hecke

    2014-06-01

    This study focuses on the symbolic meanings of the axolotl in Juan Villoro’s novel Materia dispuesta and the way the author approaches the concept of identity from both, the adolescent protagonist and Mexicans in general. This novel will be read in light of Roger Bartra’s essay, La jaula de la melancolía. Bartra uses the metaphor of the axolotl to analyse the concept of metamorphosis in the Mexican identity. Thereafter, Villoro’s novel will be compared with Julio Cortazar’s short story “Axolotl”, and Octavio Paz’s poem “Salamandra”. This comparison will allow to amplify the perspective and deepen the analysis of this hybrid animal by Villoro. The study of the axolotl demonstrates that Villoro revives the ancient aztec mythology about this amphibian, that was the representation of the god Xolotl, and that he introduces at the same time new meanings. It is in that combination of both perspectives that the richness of Villoro’s literary universe will be revealed.

  20. About several classes of bi-orthogonal polynomials and discrete integrable systems

    International Nuclear Information System (INIS)

    Chang, Xiang-Ke; Chen, Xiao-Min; Hu, Xing-Biao; Tam, Hon-Wah

    2015-01-01

    By introducing some special bi-orthogonal polynomials, we derive the so-called discrete hungry quotient-difference (dhQD) algorithm and a system related to the QD-type discrete hungry Lotka–Volterra (QD-type dhLV) system, together with their Lax pairs. These two known equations can be regarded as extensions of the QD algorithm. When this idea is applied to a higher analogue of the discrete-time Toda (HADT) equation and the quotient–quotient-difference (QQD) scheme proposed by Spicer, Nijhoff and van der Kamp, two extended systems are constructed. We call these systems the hungry forms of the higher analogue discrete-time Toda (hHADT) equation and the quotient-quotient-difference (hQQD) scheme, respectively. In addition, the corresponding Lax pairs are provided. (paper)

  1. Environmental Assessment to Construct a Perimeter Fence at Georgetown Military Family Housing Travis Air Force Base, Fairfield, California

    Science.gov (United States)

    2011-07-06

    Herpetology 28(2): 159-164. California Department ofFish and Game. 2011. RAREFIND. Natural Heritage Division, Sacramento, California. Feaver, P. E...California tiger salamander. Journal of Herpetology 30(2): 282-285. Morey, S. R. 1998. Pool duration influences age and body mass at metamorphosis in the...V.J. 1998. Natural History Notes: Ambystoma ca/iforniense (Central California tiger salamander). Survey technique. Herpetological Review 29:96

  2. Environmental Assessment: Invasive Pest Plant Management

    Science.gov (United States)

    2005-01-01

    Silvilagus floridanus Amphibians Eastern newt Notophthalmus viridescens Spotted salamander Ambystoma maculatum Two-lined salamander Eurycea...Annual EnQeron annuus c A Geranium. Carolina Geranium carotinia.num - c WA!B Geranium, Cranesbill Geranium maculatum c c WA!B Ground 01erry...Physalis heterophyffa c p Hemlock, Poison Conium macula/urn c 6 B Hen bit Lamium amplexicau/e c 3 WA/B Hoary Cress Cardarfa spp. c p Houndstongue

  3. Ecological equivalency as a tool for endangered species management.

    Science.gov (United States)

    Searcy, Christopher A; Rollins, Hilary B; Shaffer, H Bradley

    2016-01-01

    The use of taxon substitutes for extinct or endangered species is a controversial conservation measure. We use the example of the endangered California tiger salamander (Ambystoma californiense; CTS), which is being replaced by hybrids with the invasive barred tiger salamander (Ambystoma mavortium), to illustrate a strategy for evaluating taxon substitutes based on their position in a multivariate community space. Approximately one-quarter of CTS's range is currently occupied by "full hybrids" with 70% nonnative genes, while another one-quarter is occupied by "superinvasives" where a specific set of 3/68 genes comprising 4% of the surveyed genome is nonnative. Based on previous surveys of natural CTS breeding ponds, we stocked experimental mesocosms with field-verified, realistic densities of tiger salamander larvae and their prey, and used these mesocosms to evaluate ecological equivalency between pure CTS, full hybrids, and superinvasives in experimental pond communities. We also included a fourth treatment with no salamanders present to evaluate the community effects of eliminating Ambystoma larvae altogether. We found that pure CTS and superinvasive larvae were ecologically equivalent, because their positions in the multivariate community space were statistically indistinguishable and they did not differ significantly along any univariate community axes. Full hybrids were ecologically similar, but not equivalent, to the other two genotypes, and the no-Ambystoma treatment was by far the most divergent. We conclude that, at least for the larval stage, superinvasives are adequate taxon substitutes for pure CTS and should probably be afforded protection under the Endangered Species Act. The proper conservation status for full hybrids remains debatable.

  4. “Yummy” versus “Yucky”!

    DEFF Research Database (Denmark)

    Piqueras-Fiszman, Betina; Kraus, Alexandra Anita; Spence, Charles

    2014-01-01

    designed to investigate motivational approach and avoidance responses towards foods. Fifty non-dieting participants varying in terms of their hunger state (hungry vs. not hungry) reported their explicit evaluations of pleasantness, wanting, and disgust towards the idea of tasting each of the food images...... that were shown. Their motivational tendencies towards those food items were assessed indirectly using a joystick-based approach-avoidance procedure. For each of the food images that were presented, the participants had to move the joystick either towards or away from themselves (approach and avoidance...

  5. Biståndets framgång i Ghana : En jämförande fallstudie av Hungerprojektet och ActionAids biståndsarbete i Ghana

    OpenAIRE

    Drugge, Jessica; Svensson, Elizabeth

    2015-01-01

    In the world today there are 842 million people hungry, which corresponds to the population of the US, Japan and Europe combined. The reason for their hunger is not lack of food, according to the UN, there are enough resources in the world for everyone to be satisfied. The majority of the hungry live in developing countries; in rural or slum areas and its mainly women and children.1 In order to among other things, to correct this untenable situation the Millennium Development Goals were creat...

  6. Facilitating Smoking Cessation and Preventing Relapse in Primary Care: Minimizing Weight Gain by Reducing Alcohol Consumption

    Science.gov (United States)

    2012-01-01

    free yogurt , when you are hungry between meals. ! Do not deny yourself an occasional “treat.” If you crave ice cream, enjoy a small cone. ! Choose...fattening alternative. Wine • Sweet wines, such as port, sherry, and dessert wines, have sugar added to the fermentation and thus have a higher

  7. Museum Web search behavior of special interest visitors

    DEFF Research Database (Denmark)

    Skov, Mette; Ingwersen, Peter

    2014-01-01

    content analysis. It was found that metadata elements on factual object related information, provenience, and historic context was indicated to be relevant by the majority of the respondents, characterising the group of special interest museum visitors as information hungry. Further, four main...

  8. Feeding broiler breeder flocks in relation to bird welfare aspects

    NARCIS (Netherlands)

    Jong, de I.C.; Krimpen, van M.M.

    2011-01-01

    To ensure health and reproductive capacity of the birds, broiler breeders are fed restricted during the rearing period, and to a lesser extent also during the production period. Although restricted feeding improves health and thereby bird welfare, on the other hand the birds are chronically hungry

  9. Impact of nutrition on welfare aspects of broiler breeder flocks

    NARCIS (Netherlands)

    Krimpen, van M.M.; Jong, de I.C.

    2014-01-01

    To ensure health and reproductive performance, broiler breeders are feed restricted during the rearing period and, to a lesser extent, during the production period. Although restricted feeding improves health and bird welfare, on the other hand the birds are chronically hungry and suffer from

  10. The State of Food Insecurity in the World: A news brief from Food ...

    African Journals Online (AJOL)

    In the developing world, 790 million people do not have enough to eat, according to the most recent estimates (1995/97). That represents a decline of 40 million compared to 1990/92. At the World Food Summit in 1996, world leaders pledged to reduce the number of hungry people to around 400 million by 2015. At the ...

  11. I AM THE BREAD OF LIFE. IMAGERY IN JOHN 6:32-51

    African Journals Online (AJOL)

    admin

    by referring to his special relation to the Father (John 1:18; 5:19ff.). If they are people who are ..... of images of the Father giving bread from heaven to hungry people who eat it and will be ... and meet destiny from hunger”. Hunger is indeed a ...

  12. A Unit History of the 315th Bomb Wing: 1944-1946

    Science.gov (United States)

    1986-03-01

    Commanding Officer down to the newest buck private, of a coming rendezvous with destiny , one would have to come to its present location at Robins Field...tired, hungry, and grimy men reached the pitch black confines of the embryo airfield, loaded with one another’s gear and equipment." (38:Apr 45) Col

  13. Sustainable Product Innovation : The Importance of the Front-End Stage in the Innovation Process

    NARCIS (Netherlands)

    Dewulf, K.R.

    2013-01-01

    With an overpopulated planet, hungry for electricity and resources, sustainability will be one of the biggest challenges in the future. Present production and consumption patterns are causing serious environmental and human problems and cannot be sustained in a world with rising human aspirations.

  14. Fast Huffman decoding by exploiting data level parallelism

    NARCIS (Netherlands)

    Drijvers, T.; Alba Pinto, C.A.; Corporaal, H.; Mesman, B.; Braak, van den G.J.W.; Kurdahi, F.J.; Takala, J.

    2010-01-01

    The frame rates and resolutions of digital videos are on the rising edge. Thereby, pushing the compression ratios of video coding standards to their limits, resulting in more complex and computational power hungry algorithms. Programmable solutions are gaining interest to keep up the pace of the

  15. How Do We Think about Death?--A Cultural Glance of Superstitious Ideas from Chinese and Western Ghost Festivals

    Science.gov (United States)

    Zhang, Wenli

    2009-01-01

    Superstitious ideas are always in people's life in spite of scientific and technological advancement. Hungry Ghost Festival in China, Halloween in some western countries and Day of the Dead in Mexico are three religious festivals which are observed every year. They reveal people's idea about ghosts and spirits after death. They also include…

  16. Emotional stimuli exert parallel effects on attention and memory.

    Science.gov (United States)

    Talmi, Deborah; Ziegler, Marilyne; Hawksworth, Jade; Lalani, Safina; Herman, C Peter; Moscovitch, Morris

    2013-01-01

    Because emotional and neutral stimuli typically differ on non-emotional dimensions, it has been difficult to determine conclusively which factors underlie the ability of emotional stimuli to enhance immediate long-term memory. Here we induced arousal by varying participants' goals, a method that removes many potential confounds between emotional and non-emotional items. Hungry and sated participants encoded food and clothing images under divided attention conditions. Sated participants attended to and recalled food and clothing images equivalently. Hungry participants performed worse on the concurrent tone-discrimination task when they viewed food relative to clothing images, suggesting enhanced attention to food images, and they recalled more food than clothing images. A follow-up regression analysis of the factors predicting memory for individual pictures revealed that food images had parallel effects on attention and memory in hungry participants, so that enhanced attention to food images did not predict their enhanced memory. We suggest that immediate long-term memory for food is enhanced in the hungry state because hunger leads to more distinctive processing of food images rendering them more accessible during retrieval.

  17. Using a Study Circle Model to Improve Teacher Confidence and Proficiency in Delivering Pronunciation Instruction in the Classroom

    Science.gov (United States)

    Echelberger, Andrea; McCurdy, Suzanne Gichrist; Parrish, Betsy

    2018-01-01

    Adult English language learners are hungry for pronunciation instruction that helps them to "crack the code" of speaking intelligible English (Derwing, 2003). Research indicates benefits of pronunciation instruction with adult learners, yet many teachers believe they lack the knowledge and background to make sound instructional decisions…

  18. 78 FR 62335 - National School Lunch Week, 2013

    Science.gov (United States)

    2013-10-18

    ... more of our children are at risk for preventable health problems including diabetes and heart disease... their children with decent meals for the long school day, President Harry Truman signed the National... child should go hungry. And today, with more than 32 million children participating in the National...

  19. The size of the thymus: an important immunological diagnostic tool?

    DEFF Research Database (Denmark)

    Jeppesen, Dorthe Lisbeth

    2003-01-01

    The report on the influence of seasonal factors on thymic size in early life describes a pattern of ultrasonographically measured thymic growth in Gambian infants including the finding of a smaller thymus in the hungry season. These factors raise a number of important questions: Is the size...

  20. World Hunger: Ten Myths. Fourth Edition, Revised.

    Science.gov (United States)

    Lappe, Frances Moore; Collins, Joseph

    Although there are a number of complex political, economic, and ecological issues at the root of world hunger, a number of myths have been perpetuated to explain why hunger exists. One myth says that people are hungry because of scarcity; in fact, hunger exists in the face of plenty. The earth is producing more than enough to nourish every human…

  1. Confronting World Hunger.

    Science.gov (United States)

    Huddleston, Barbara

    1983-01-01

    The idea that food should be a universally accepted human right has been the focus of worldwide attention aimed primarily at increasing production at the national level and on reducing price fluctuations in world markets. However, the problem of individual human needs must be simultaneously addressed. The largest number of hungry people live in…

  2. Hunger: The World's Oldest Sorrow.

    Science.gov (United States)

    Miller, Judith; Miller, Mark

    1985-01-01

    No human problem is older than starvation. Authorities agree that poverty and unequal distribution of resources are the basic causes of hunger. The hungry are ignored by the world because they have no political power and even less economic strength. How to build a world without hunger is discussed. (RM)

  3. Transgenic Crops to Address Third World Hunger? A Critical Analysis

    Science.gov (United States)

    Rosset, Peter M.

    2005-01-01

    Industry and mainstream research and policy institutions often suggest that transgenic crop varieties can raise the productivity of poor third world farmers, feed the hungry, and reduce poverty. These claims are critically evaluated by examining global-hunger data, the constraints that affect the productivity of small farmers in the third world,…

  4. Finding Solutions to Hunger: Kids Can Make a Difference. A Sourcebook for Middle and Upper School Teachers.

    Science.gov (United States)

    Kempf, Stephanie

    This manual engages young people in the task of helping save their less fortunate peers from hunger and starvation. The activities give students the knowledge to take action on the causes of hunger and their capacity to change the world. Global hunger, caused by the economic and social forces that result in a billion people going to bed hungry on…

  5. Overcoming World Hunger: The Challenge Ahead. Report of the Presidential Commission on World Hunger. An Abridged Version.

    Science.gov (United States)

    Presidential Commission on World Hunger, Washington, DC.

    This U.S. presidential commission report outlines specific recommendations for eliminating world hunger in the 1980's. Following a summarization of world hunger problems, the report addresses specific ways to deal with world hunger. Short-term goals include taking immediate action to ensure that poor people are not hungry, assuring that infants…

  6. World Hunger: Learning to Meet the Challenge.

    Science.gov (United States)

    Joy, Carrol; Regan, Patrick

    This elementary and secondary level world hunger curriculum guide is designed both to educate teachers and students in the basics of world hunger, and to guide them in organizing student groups to take action that will combat hunger. A background information section is presented in part 1, which describes who and where the hungry are, what it is…

  7. Bread for the World Membership Survey and Analysis Project. Final Report.

    Science.gov (United States)

    Whitaker, William H.; And Others

    This survey was conducted in 1984 of current and former members of Bread for the World (BFW) in order to further understanding of the characteristics, attitudes, level of participation, and needs of people involved with hunger issues and the needs of hungry people. A questionnaire was mailed to 1,296 current and 738 former members. This final…

  8. World Food Day: Curriculum, Grades 8-12.

    Science.gov (United States)

    Shiman, David

    Over one billion of the world's people are chronically hungry. For them, life is a hunger cycle characterized by vulnerability to disease, stunted physical and mental development, reduced energy and motivation, and low work productivity. This curriculum guide is designed to channel student awareness and concern into effective action. The…

  9. Modeling User Behavior and Attention in Search

    Science.gov (United States)

    Huang, Jeff

    2013-01-01

    In Web search, query and click log data are easy to collect but they fail to capture user behaviors that do not lead to clicks. As search engines reach the limits inherent in click data and are hungry for more data in a competitive environment, mining cursor movements, hovering, and scrolling becomes important. This dissertation investigates how…

  10. Global communication schemes for the numerical solution of high-dimensional PDEs

    DEFF Research Database (Denmark)

    Hupp, Philipp; Heene, Mario; Jacob, Riko

    2016-01-01

    The numerical treatment of high-dimensional partial differential equations is among the most compute-hungry problems and in urgent need for current and future high-performance computing (HPC) systems. It is thus also facing the grand challenges of exascale computing such as the requirement...

  11. Good Choices in Hard Times: Fifteen Ideas for States To Reduce Hunger and Stimulate the Economy.

    Science.gov (United States)

    Albee, Michelle; Cates, Jessica; Hayes, Louise; Henchy, Geri; Hess, Doug; Odell, Denise; Parker, Lynn; Phelps, Anne; Schwartz, Sonya; Vollinger, Ellen; Weedall, Crystal; Weill, Jim; Woo, Nicole

    This resource guide puts forth 15 ideas for actions in food stamp and other child nutrition programs that states, schools, and cities can implement to feed more hungry low-income residents, especially children, and provide a direct federal economic stimulus for the state and its businesses. The guide asserts that states risk accelerating a…

  12. Model checking and evaluating QoS of batteries in MPSoC dataflow applications via hybrid automata (extended version)

    NARCIS (Netherlands)

    Ahmad, W.; Jongerden, M.R.; Stoelinga, Mariëlle Ida Antoinette; van de Pol, Jan Cornelis

    2016-01-01

    System lifetime is always a major design impediment for battery-powered mobile embedded systems such as, cell phones and satellites. The increasing gap between energy demand of portable devices and their battery capacities is further limiting durability of mobile devices. For example, energy-hungry

  13. Aberrant Cerebral Blood Flow in Response to Hunger and Satiety in Women Remitted from Anorexia Nervosa

    Directory of Open Access Journals (Sweden)

    Christina E. Wierenga

    2017-07-01

    Full Text Available The etiology of pathological eating in anorexia nervosa (AN remains poorly understood. Cerebral blood flow (CBF is an indirect marker of neuronal function. In healthy adults, fasting increases CBF, reflecting increased delivery of oxygen and glucose to support brain metabolism. This study investigated whether women remitted from restricting-type AN (RAN have altered CBF in response to hunger that may indicate homeostatic dysregulation contributing to their ability to restrict food. We compared resting CBF measured with pulsed arterial spin labeling in 21 RAN and 16 healthy comparison women (CW when hungry (after a 16-h fast and after a meal. Only remitted subjects were examined to avoid the confounding effects of malnutrition on brain function. Compared to CW, RAN demonstrated a reduced difference in the Hungry − Fed CBF contrast in the right ventral striatum, right subgenual anterior cingulate cortex (pcorr < 0.05 and left posterior insula (punc < 0.05; RAN had decreased CBF when hungry versus fed, whereas CW had increased CBF when hungry versus fed. Moreover, decreased CBF when hungry in the left insula was associated with greater hunger ratings on the fasted day for RAN. This represents the first study to show that women remitted from AN have aberrant resting neurovascular function in homeostatic neural circuitry in response to hunger. Regions involved in homeostatic regulation showed group differences in the Hungry − Fed contrast, suggesting altered cellular energy metabolism in this circuitry that may reduce motivation to eat.

  14. INCREASE IN DOPAMINE RELEASE FROM THE NUCLEUS-ACCUMBENS IN RESPONSE TO FEEDING - A MODEL TO STUDY INTERACTIONS BETWEEN DRUGS AND NATURALLY ACTIVATED DOPAMINERGIC-NEURONS IN THE RAT-BRAIN

    NARCIS (Netherlands)

    WESTERINK, BHC; TEISMAN, A; DEVRIES, JB

    The aim of the present study was to investigate the interactions between the in vivo release of dopamine and certain drugs, during conditions of increased dopaminergic activity. Dopaminergic neurons in the nucleus accumbens were activated by feeding hungry rats. 48-96 h after implantation of a

  15. The Real Rebalancing: American Diplomacy and the Tragedy of President Obama’s Foreign Policy

    Science.gov (United States)

    2015-10-01

    engagement” to its list of warfight- ing functions, along with mission command, move- ment and maneuver, intelligence , fires, sustainment, and protection...technologies, and foreign intelligence collection. Even earlier, see National Security Strategy, Washington, DC: The White House, August 1991, p. 8... Malnutrition , illiteracy and poverty put dangerous pressures on democratic institutions as hungry, uneducated or poorly 33 housed citizens are ripe for

  16. Very wide register : an asymmetric register file organization for low power embedded processors.

    NARCIS (Netherlands)

    Raghavan, P.; Lambrechts, A.; Jayapala, M.; Catthoor, F.; Verkest, D.T.M.L.; Corporaal, H.

    2007-01-01

    In current embedded systems processors, multi-ported register files are one of the most power hungry parts of the processor, even when they are clustered. This paper presents a novel register file architecture, which has single ported cells and asymmetric interfaces to the memory and to the

  17. A blind spot in food and nutrition security: where culture and social change shape the local food plate

    NARCIS (Netherlands)

    Noack, A.L.; Pouw, N.R.M.

    2015-01-01

    It is estimated that over 800 million people are hungry each day and two billion are suffering from the consequences of vitamin and mineral deficiencies. While a paradigm shift towards a multi-dimensional and multi-sectoral approach to food and nutrition insecurity is emerging, technical approaches

  18. Quantum-dot based microdisk lasers and semiconductor optical amplifiers operating at 1.55 μm

    NARCIS (Netherlands)

    Solis Trapala, K.

    2011-01-01

    Optical data transmission allows for high-speed and low-loss transmission over longer distances than the electronic counterpart. Yet, the advantage of using fiber-optic communications has been restrained by power hungry opto-electronic conversions at the nodes. These are required for switching

  19. School Breakfast Scorecord, 2002. Twelfth Annual Status Report on the School Breakfast Program.

    Science.gov (United States)

    Hess, Doug; Woo, Nicole; Phelps, Anne; Parker, Lynn; Weill, Jim

    The School Breakfast Program provides breakfast to millions of children from low-income families who otherwise might go hungry in the morning and be less ready to learn. This report is the eleventh from the Food Research and Action Center (FRAC) to examine the program, its benefits, and the performance of the nation and of each state in reaching…

  20. School Breakfast Scorecard, 2003: Thirteenth Annual Status Report on the School Breakfast Program.

    Science.gov (United States)

    Woo, Nicole; Parker, Lynn; Weill, Jim; Vuong, Bi; Hess, Doug; Weinstein-Tull, Justin; Putney, Wanda

    The School Breakfast Program provides breakfast to millions of children from low-income families who otherwise might go hungry in the morning and be less ready to learn. This report is the thirteenth from the Food Research and Action Center (FRAC) to examine the program, its benefits, and the performance of the nation and of each state in reaching…

  1. Agriculture’s Ethical Horizon, book review

    Science.gov (United States)

    Roughly 6.5 billion people inhabit the earth, but over 1 billion people regularly go hungry. This food shortfall poses an ethical dilemma for agriculture, and Agriculture's Ethical Horizon grapples with this dilemma. It argues that agricultural productivity has been the quintessential value of agr...

  2. Seeking to Expand Middle Level Success to All Students: A Not-So-Secret Recipe

    Science.gov (United States)

    White, Jesse

    2014-01-01

    The recipe for success of Strive Preparatory Charter School (formerly West Denver Preparatory Charter School) is not a secret. This summer program, turned four-campus, middle level phenomenon, is proving to satisfy the appetite of parents hungry for a change in their children's educational opportunities. The intent of this article is to share a…

  3. Boar taint detection using parasitoid biosensors

    Science.gov (United States)

    To evaluate the potential for a non-stinging wasp to be used as a biosensor in the pig industry, we trained wasps to 3 individual chemicals associated with boar taint. Training consisted of presenting the odors to hungry wasps while they were feeding on sugar. This associates the chemical with a fo...

  4. Child Advocacy in the United States: The Work of the Children's Defense Fund. Innocenti Essays No. 2.

    Science.gov (United States)

    Weill, James D.

    This essay provides an overview of the goals and activities of the Children's Defense Fund (CDF), an advocacy group headquartered in Washington, D.C. that works to improve the well-being of American children through systemic change and whose goal is to make it unacceptable for any child in the United States to grow up homeless, hungry, sick,…

  5. A Survey of the Purpose of Extra Classes Provided in Primary ...

    African Journals Online (AJOL)

    Is it a money-spinning venture for the cash hungry teachers or is it a valid teaching exercise with recognisable benefits to the learner? The focus of this study was to investigate the nature and purpose of extra lessons and how they impact on the quality of education that is provided in the schools. The study was a descriptive ...

  6. The household food budget of the wealthy and the poor in South Africa

    African Journals Online (AJOL)

    BlignautAS

    ISSN 0378-5254 Journal of Family Ecology and Consumer Sciences, Vol 33, 2005. The household food ... waaronder bees- en kalfsvleis, pluimvee, skaap- en lamsvleis ... lion children under the age of 12 in America go hungry during parts of ...

  7. Neural Correlates of Decision Making on a Gambling Task

    Science.gov (United States)

    Carlson, Stephanie M.; Zayas, Vivian; Guthormsen, Amy

    2009-01-01

    Individual differences in affective decision making were examined by recording event-related potentials (ERPs) while 74 typically developing 8-year-olds (38 boys, 36 girls) completed a 4-choice gambling task (Hungry Donkey Task; E. A. Crone & M. W. van der Molen, 2004). ERP results indicated: (a) a robust P300 component in response to feedback…

  8. Higher Prices, Fewer Choices: Shopping for Food in Rural America.

    Science.gov (United States)

    Morris, Patricia McGrath

    The Food Stamp Program is the U.S. government's primary program to prevent the rural poor from going hungry. Food stamp allotments are set each year based on the cost of the "Thrifty Food Plan" (TFP), a minimally adequate diet defined by the U.S. Department of Agriculture (USDA), which sets costs by examining average food prices in urban…

  9. Crops in silico: Generating virtual crops using an integrative and multi-scale modeling platform

    Science.gov (United States)

    There are currently 795 million hungry people in the world and 98 percent of them are in developing countries. Food demand is expected to increase by 70% by 2050. With a reduction in arable land, decreases in water availability, and an increasing impact of climate change, innovative technologies are...

  10. Protective Services Chili Cookoff Full of Good Food, Good Fun, and “Tough Choices” | Poster

    Science.gov (United States)

    This year’s Protective Services Chili Cookoff was marked by blazing-hot chili and fiery competition as 15 entrants contended for the attention and adoration of approximately 150 hungry attendees. The competition is a fixture at NCI at Frederick and regularly features an array of culinary concoctions, from which the visitors rank their choices for first, second, and third place.

  11. Multi-core fiber amplifier arrays for intra-satellite links

    Science.gov (United States)

    Kechagias, Marios; Crabb, Jonathan; Stampoulidis, Leontios; Farzana, Jihan; Kehayas, Efstratios; Filipowicz, Marta; Napierala, Marek; Murawski, Michal; Nasilowski, Tomasz; Barbero, Juan

    2017-09-01

    In this paper we present erbium doped fibre (EDF) aimed at signal amplification within satellite photonic payload systems operating in C telecommunication band. In such volume-hungry applications, the use of advanced optical transmission techniques such as space division multiplexing (SDM) can be advantageous to reduce the component and cable count.

  12. Cystic fibrosis - nutrition

    Science.gov (United States)

    ... and crackers, muffins, or trail mix. Try to eat regularly, even if it is only a few bites. Or, include a nutrition supplement or milkshake. Be flexible. If you aren't hungry at dinner time, make breakfast, mid-morning snacks, and lunch ...

  13. Be a Healthy Role Model for Children: 10 Tips for Setting Good Examples

    Science.gov (United States)

    ... Discuss where vegetables, fruits, grains, dairy, and protein foods calls later. Try to make eating meals a stress-free time. 7 listen to your child If your child says he or she is hungry, offer a small, healthy snack—even if it is not a scheduled ...

  14. Publications | Page 93 | IDRC - International Development Research ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Results 921 - 930 of 6389 ... Going West: Why the Canadian Prairies might hold the key to feeding a hungry world. More than two decades ago, southern Manitoba rancher and federal agriculture minister Charlie Mayer returned to Canada from a United Nations meeting in Rome troubled by what he had heard.

  15. Overestimating resource value and its effects on fighting decisions.

    Directory of Open Access Journals (Sweden)

    Lee Alan Dugatkin

    Full Text Available Much work in behavioral ecology has shown that animals fight over resources such as food, and that they make strategic decisions about when to engage in such fights. Here, we examine the evolution of one, heretofore unexamined, component of that strategic decision about whether to fight for a resource. We present the results of a computer simulation that examined the evolution of over- or underestimating the value of a resource (food as a function of an individual's current hunger level. In our model, animals fought for food when they perceived their current food level to be below the mean for the environment. We considered seven strategies for estimating food value: 1 always underestimate food value, 2 always overestimate food value, 3 never over- or underestimate food value, 4 overestimate food value when hungry, 5 underestimate food value when hungry, 6 overestimate food value when relatively satiated, and 7 underestimate food value when relatively satiated. We first competed all seven strategies against each other when they began at approximately equal frequencies. In such a competition, two strategies--"always overestimate food value," and "overestimate food value when hungry"--were very successful. We next competed each of these strategies against the default strategy of "never over- or underestimate," when the default strategy was set at 99% of the population. Again, the strategies of "always overestimate food value" and "overestimate food value when hungry" fared well. Our results suggest that overestimating food value when deciding whether to fight should be favored by natural selection.

  16. A Fully Integrated Bluetooth Low-Energy Transmitter in 28 nm CMOS With 36% System Efficiency at 3 dBm

    NARCIS (Netherlands)

    Babaie, M.; Kuo, F.W.; Chen, H; Cho, L.C.; Jou, C.P.; Hsueh, F.L.; Shahmohammadi, M.; Staszewski, R.B.

    2016-01-01

    We propose a new transmitter architecture for ultra-low power radios in which the most energy-hungry RF circuits operate at a supply just above a threshold voltage of CMOS transistors. An all-digital PLL employs a digitally controlled oscillator with switching current sources to reduce supply

  17. Headache Sufferers' Diet

    Science.gov (United States)

    ... at each meal/snack (i.e. milk, meat, fish) and should avoid eating high sugar foods by themselves, especially when excessively hungry. These actions ... following lists). You can introduce them one ‘new’ food every three days and ... can have an additive effect. For instance, being over tired is a ...

  18. These Tough Economic Times

    Science.gov (United States)

    Desrochers, John E.; Cowan, Katherine C.; Christner, Ray W.

    2009-01-01

    Research has shown that students' social, emotional, and behavioral health affects their academic achievement. This has enormous implications for teachers, school mental health providers, and the students themselves. A student who is hungry, disengaged, preoccupied, or behaviorally disruptive simply is not going to respond as well to even the best…

  19. Search Results | Page 849 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Results 8481 - 8490 of 9176 ... Farmer groups key to boosting technology adoption in Kenya ... Climate-smart Kenyan crop hits a setback – hungry birds ... outside the home because of their dual role as caregivers and breadwinners, and the lack ...

  20. Functional neuroimaging of satiation and satiety

    NARCIS (Netherlands)

    Spetter, M.S.

    2012-01-01

    The main aim of this research project was to understand the effect of internal state on brain activity associated with different food and odour properties. To this end, the brain activation in response to differential taste and odour stimuli when either being hungry or satiated, and additionally,

  1. Microbolometer spectrometer opens hoist of new applications

    NARCIS (Netherlands)

    Leijtens, J.A.P.; Smorenburg, C.; Escudero, I.; Boslooper, E.C.; Visser, H.; Helden, W.A. van; Breussin, F.N.

    2004-01-01

    Current Thermal infra red ( 7..14μm) multispectral imager instruments use cryogenically cooled Mercury Cadmium Telluride (MCT or HgCdTe) detectors. This causes the instruments to be bulky, power hungry and expensive. For systems that have medium NETD (Noise Equivalent Temperature Difference)

  2. Näljane vaim : sihi otsimine kaasaegses maailmas / Charles Handy

    Index Scriptorium Estoniae

    Handy, Charles

    2002-01-01

    Kapitalistlik ühiskond ja raha on vahendid, mitte eesmärgid; eesmärgid peaks iga inimene püstitama endale ise, lähtuvalt oma sisetunnetusest. Lühendatud tõlge Charles Handy raamatust - "The Hungry Spirit Beyond Capitalism - a Quest of Purpose in the Modern World"

  3. Deontic Introduction: A Theory of Inference from Is to Ought

    Science.gov (United States)

    Elqayam, Shira; Thompson, Valerie A.; Wilkinson, Meredith R.; Evans, Jonathan St. B. T.; Over, David E.

    2015-01-01

    Humans have a unique ability to generate novel norms. Faced with the knowledge that there are hungry children in Somalia, we easily and naturally infer that we ought to donate to famine relief charities. Although a contentious and lively issue in metaethics, such inference from "is" to "ought" has not been systematically…

  4. To dare or not to dare? Risk management by owls in a predator-prey foraging game.

    Science.gov (United States)

    Embar, Keren; Raveh, Ashael; Burns, Darren; Kotler, Burt P

    2014-07-01

    In a foraging game, predators must catch elusive prey while avoiding injury. Predators manage their hunting success with behavioral tools such as habitat selection, time allocation, and perhaps daring-the willingness to risk injury to increase hunting success. A predator's level of daring should be state dependent: the hungrier it is, the more it should be willing to risk injury to better capture prey. We ask, in a foraging game, will a hungry predator be more willing to risk injury while hunting? We performed an experiment in an outdoor vivarium in which barn owls (Tyto alba) were allowed to hunt Allenby's gerbils (Gerbillus andersoni allenbyi) from a choice of safe and risky patches. Owls were either well fed or hungry, representing the high and low state, respectively. We quantified the owls' patch use behavior. We predicted that hungry owls would be more daring and allocate more time to the risky patches. Owls preferred to hunt in the safe patches. This indicates that owls manage risk of injury by avoiding the risky patches. Hungry owls doubled their attacks on gerbils, but directed the added effort mostly toward the safe patch and the safer, open areas in the risky patch. Thus, owls dared by performing a risky action-the attack maneuver-more times, but only in the safest places-the open areas. We conclude that daring can be used to manage risk of injury and owls implement it strategically, in ways we did not foresee, to minimize risk of injury while maximizing hunting success.

  5. New Parents: How to Get the Sleep You Need

    Science.gov (United States)

    ... Give watchful waiting a try. Sometimes, you might need to let your baby cry himself or herself to sleep. Unless you suspect that your baby is hungry ... conditions can help you get the rest you need. Remember, taking good care of ... — including getting adequate sleep — will help you take the best care of ...

  6. Battery Management Systems: Accurate State-of-Charge Indication for Battery-Powered Applications

    NARCIS (Netherlands)

    Pop, V.; Bergveld, H.J.; Danilov, D.; Regtien, Paulus P.L.; Notten, P.H.L.

    2008-01-01

    Battery Management Systems – Universal State-of-Charge indication for portable applications describes the field of State-of-Charge (SoC) indication for rechargeable batteries. With the emergence of battery-powered devices with an increasing number of power-hungry features, accurately estimating the

  7. Dallas Zoo hunts for escaped vulture

    African Journals Online (AJOL)

    shows eating off the antelopes that lions kill and everything,” Mr Brown said. The African White-backed vultures have been at the zoo since August. They're expected to be part of an exhibit that is undergoing renovations. Mr Brown said vultures are hardy, resourceful animals. When the missing bird becomes hungry,.

  8. Patterns of Radicalization: Identifying the Markers and Warning Signs of Domestic Lone Wolf Terrorists in Our Midst

    Science.gov (United States)

    2009-12-01

    from Michigan to Waco to see if he could help. “In March 1993, McVeigh was captured on film by Texas television KTVT, a CBS affiliate, sitting on the...hungry, and forsaken. Catholic Workers protest injustice, war, racism , and violence of all forms.126 Patricia participated in numerous protests

  9. On the Control of Surface Waves in Integrated Antennas : Analysis and Design Exploiting Artificial Dielectric Layers

    NARCIS (Netherlands)

    Syed, W.H.

    2015-01-01

    Planar printed antenna technologies, due to their light weight, low profile, cost effectiveness and ease of connection with the active devices (e.g., amplifiers etc.), are becoming an attractive solution for the commercial data-hungry applications, such as 60 GHz high-data rate communication.

  10. Reflections on "La Esperanza"

    Science.gov (United States)

    Cortez, Anita

    2007-01-01

    The author was recently asked to reflect on her "educational journey." As far as she can remember she has been hungry to learn. A friend once described her as having "hambres atrasadas," which he described as a kind of "hunger nipping at her heels." It goes back, of course, to her parents: Her father's and her early…

  11. Interstate Migrant Education Task Force: Migrant Health.

    Science.gov (United States)

    Education Commission of the States, Denver, CO.

    Because ill-clothed, sick, or hungry migrant children learn poorly, the Task Force has emphasized the migrant health situation in 1979. Migrant workers have a 33% shorter life expectancy, a 25% higher infant mortality rate, and a 25% higher death rate from tuberculosis and other communicable diseases than the national average. Common among…

  12. Search Results | Page 785 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Results 7841 - 7850 of 8531 ... Farmers select innovations and practices that work for them ... Climate-smart Kenyan crop hits a setback – hungry birds ... Research shows that women face particular challenges in engaging in work outside the home because of their dual role as caregivers and breadwinners, and the lack of ...

  13. 75 FR 77638 - Granting of Request for Early Termination of the Waiting Period Under the Premerger Notification...

    Science.gov (United States)

    2010-12-13

    .... 20110196 G Barry Diller. G Barry Diller. G IAC/InterActiveCorp. 20110197 G Barry Diller. G Liberty Media... Machine, Inc. d/b/a Living Social G Hungry Machine, Inc. 02-DEC-10 20110212 G Right Choice Credit Union, G.... 20110185 G Excellere Partners. G The SV Partners Limited Partnership. G AxelaCare Health Solutions, LLC...

  14. Irradiation processing of food

    International Nuclear Information System (INIS)

    Anunuso, C.I.

    1988-01-01

    Ionizing radiation is now showing new promise of contributing to the feeding of hungry populations, solving solid and liquid waste disposal problems, providing safer medical supplies, pharmaceuticals, and other commodities, and at the same time reducing energy consumption in industrial processing in general. (author)

  15. Harlem, History, and First-Year Composition: Reconstructing the Harlem of the 1930s through Multiple Research Methods

    Science.gov (United States)

    Wilson, James

    2003-01-01

    Describing the Harlem Riot of 1935, black author and poet Claude McKay wrote, "On Tuesday the crowds went crazy like the remnants of a defeated, abandoned, and hungry army. Their rioting was the gesture of despair of a bewildered, baffled, and disillusioned people". By nearly all accounts, the riot marks the historical end of the Harlem…

  16. Synthesis, physicochemical characterization, and functional ...

    African Journals Online (AJOL)

    Acha (Digitaria exilis Stapf), also known as Findi, Hungry rice, Petit mil and White fonio, is a small seeded cereal, indigenous to West Africa, which is generally classified as millet. It grows in various parts of Nigeria, Sierra Leone, Ghana, Guinea Bissau and Benin Republic. That species is the most important of a diverse ...

  17. Doubting What to Eat: A Computational Model for Food Choice Using Different Valuing Perspectives

    NARCIS (Netherlands)

    Abro, Altaf H.; Treur, Jan; Hirose, Akira; Ozawa, Seiichi; Doya, Kenji; Lee, Minho; Liu, Derong

    2016-01-01

    In this paper a computational model for the decision making process of food choices is presented that takes into account a number of aspects on which a decision can be based, for example, a temptation triggered by the food itself, a desire for food triggered by being hungry, valuing by the expected

  18. Brain Activation by Visual Food-Related Stimuli and Correlations with Metabolic and Hormonal Parameters: A fMRI Study

    NARCIS (Netherlands)

    Jakobsdottir, S.; de Ruiter, M.B.; Deijen, J.B.; Veltman, D.J.; Drent, M.L.

    2012-01-01

    Regional brain activity in 15 healthy, normal weight males during processing of visual food stimuli in a satiated and a hungry state was examined and correlated with neuroendocrine factors known to be involved in hunger and satiated states. Two functional Magnetic Resonance Imaging (fMRI) sessions

  19. The Hunger Games: Using hunger to promote healthy choices in self-control conflicts.

    Science.gov (United States)

    Cheung, Tracy T L; Kroese, Floor M; Fennis, Bob M; De Ridder, Denise T D

    2017-09-01

    The majority of existing research and conventional wisdom would advise against shopping on an empty stomach as hunger is assumed to encourage impulsive choices that typically lead to self-control failure (i.e., favouring short-term gratifications at the expense of long-term goals). Nonetheless, through two studies the current research aims to demonstrate that hungry consumers would not always be disadvantaged when encountering a self-control conflict involving a trade-off choice between a healthy vs. a more palatable but unhealthy choice. Particularly we posit that the choice outcome of the self-control conflict is dependent on contextual cues, such that hungry consumers with the tendency to make fast decisions could benefit from following a social proof heuristic promoting the healthy options. In Study 1, we indeed observed participants' self-reported hunger to be negatively associated with state self-control, but as most participants generally experienced low levels of hunger we did not observe apparent effects of hunger on food choice (DV), and correspondingly the potential influence of the social proof heuristic in moderating the choice outcome. However, in Study 2 where hunger was manipulated, we found hungry participants making significantly less healthy choices than satiated participants, but a social proof heuristic mitigated this effect (i.e., in the presence of social proof heuristic hungry participants made just as many healthy food choices as satiated participants; and hungry participants made more healthy choices in the social proof condition than in the no heuristic condition). These findings support our approach of providing contextual cues in the environment in order to work with, rather than against, the impulsivity triggered by hunger to promote successful self-control behaviours. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Spatial distribution of prominin-1 (CD133-positive cells within germinative zones of the vertebrate brain.

    Directory of Open Access Journals (Sweden)

    József Jászai

    Full Text Available In mammals, embryonic neural progenitors as well as adult neural stem cells can be prospectively isolated based on the cell surface expression of prominin-1 (CD133, a plasma membrane glycoprotein. In contrast, characterization of neural progenitors in non-mammalian vertebrates endowed with significant constitutive neurogenesis and inherent self-repair ability is hampered by the lack of suitable cell surface markers. Here, we have investigated whether prominin-1-orthologues of the major non-mammalian vertebrate model organisms show any degree of conservation as for their association with neurogenic geminative zones within the central nervous system (CNS as they do in mammals or associated with activated neural progenitors during provoked neurogenesis in the regenerating CNS.We have recently identified prominin-1 orthologues from zebrafish, axolotl and chicken. The spatial distribution of prominin-1-positive cells--in comparison to those of mice--was mapped in the intact brain in these organisms by non-radioactive in situ hybridization combined with detection of proliferating neural progenitors, marked either by proliferating cell nuclear antigen or 5-bromo-deoxyuridine. Furthermore, distribution of prominin-1 transcripts was investigated in the regenerating spinal cord of injured axolotl.Remarkably, a conserved association of prominin-1 with germinative zones of the CNS was uncovered as manifested in a significant co-localization with cell proliferation markers during normal constitutive neurogenesis in all species investigated. Moreover, an enhanced expression of prominin-1 became evident associated with provoked, compensatory neurogenesis during the epimorphic regeneration of the axolotl spinal cord. Interestingly, significant prominin-1-expressing cell populations were also detected at distinct extraventricular (parenchymal locations in the CNS of all vertebrate species being suggestive of further, non-neurogenic neural function

  1. Irradiation inhibits the regeneration of aneurogenic limbs

    International Nuclear Information System (INIS)

    Wallace, H.; Maden, M.

    1976-01-01

    The developing arms of axolotl larvae from the 2-digit stage onward and the aneurogenic arms of surgically denervated larvae maintained in parabiosis are able to regenerate after amputation. Such regeneration is uniformly inhibited by local irradiation of the arm, whether innervated or not. This demonstration refutes a recent hypothesis that x-rays interfere with a special activity of nerves required for regeneration, and supports the earlier concept that x-rays act directly on those cells which must proliferate to form the regenerated tissues

  2. Open Source Software Projects Needing Security Investments

    Science.gov (United States)

    2015-06-19

    modtls, BouncyCastle, gpg, otr, axolotl. 7. Static analyzers: Clang, Frama-C. 8. Nginx. 9. OpenVPN . It was noted that the funding model may be similar...to OpenSSL, where consulting funds the company. It was also noted that OpenVPN needs to correctly use OpenSSL in order to be secure, so focusing on...Dovecot 4. Other high-impact network services: OpenSSH, OpenVPN , BIND, ISC DHCP, University of Delaware NTPD 5. Core infrastructure data parsers

  3. Amphioxus and lamprey AP-2 genes: implications for neural crest evolution and migration patterns

    Science.gov (United States)

    Meulemans, Daniel; Bronner-Fraser, Marianne

    2002-01-01

    The neural crest is a uniquely vertebrate cell type present in the most basal vertebrates, but not in cephalochordates. We have studied differences in regulation of the neural crest marker AP-2 across two evolutionary transitions: invertebrate to vertebrate, and agnathan to gnathostome. Isolation and comparison of amphioxus, lamprey and axolotl AP-2 reveals its extensive expansion in the vertebrate dorsal neural tube and pharyngeal arches, implying co-option of AP-2 genes by neural crest cells early in vertebrate evolution. Expression in non-neural ectoderm is a conserved feature in amphioxus and vertebrates, suggesting an ancient role for AP-2 genes in this tissue. There is also common expression in subsets of ventrolateral neurons in the anterior neural tube, consistent with a primitive role in brain development. Comparison of AP-2 expression in axolotl and lamprey suggests an elaboration of cranial neural crest patterning in gnathostomes. However, migration of AP-2-expressing neural crest cells medial to the pharyngeal arch mesoderm appears to be a primitive feature retained in all vertebrates. Because AP-2 has essential roles in cranial neural crest differentiation and proliferation, the co-option of AP-2 by neural crest cells in the vertebrate lineage was a potentially crucial event in vertebrate evolution.

  4. Social Welfare and the Psychology of Food Sharing: Short-Term Hunger Increases Support for Social Welfare

    DEFF Research Database (Denmark)

    Petersen, Michael Bang; Aarøe, Lene; Jensen, Niels Holm

    2014-01-01

    Do politically irrelevant events influence important policy opinions? Previous research on social welfare attitudes has emphasized the role of political factors such as economic self-interest and ideology. Here, we demonstrate that attitudes to social welfare are also influenced by short-term flu......—we consistently find that hungry individuals act in a greedier manner but describe themselves as more cooperative and express greater support for social welfare.......Do politically irrelevant events influence important policy opinions? Previous research on social welfare attitudes has emphasized the role of political factors such as economic self-interest and ideology. Here, we demonstrate that attitudes to social welfare are also influenced by short......-term fluctuations in hunger. Using theories in evolutionary psychology, we predict that hungry individuals will be greedier and take more resources from others while also attempting to induce others to share by signaling cooperative intentions and expressing support for sharing, including evolutionarily novel forms...

  5. Always gamble on an empty stomach: hunger is associated with advantageous decision making.

    Directory of Open Access Journals (Sweden)

    Denise de Ridder

    Full Text Available Three experimental studies examined the counterintuitive hypothesis that hunger improves strategic decision making, arguing that people in a hot state are better able to make favorable decisions involving uncertain outcomes. Studies 1 and 2 demonstrated that participants with more hunger or greater appetite made more advantageous choices in the Iowa Gambling Task compared to sated participants or participants with a smaller appetite. Study 3 revealed that hungry participants were better able to appreciate future big rewards in a delay discounting task; and that, in spite of their perception of increased rewarding value of both food and monetary objects, hungry participants were not more inclined to take risks to get the object of their desire. Together, these studies for the first time provide evidence that hot states improve decision making under uncertain conditions, challenging the conventional conception of the detrimental role of impulsivity in decision making.

  6. Always gamble on an empty stomach: hunger is associated with advantageous decision making.

    Science.gov (United States)

    de Ridder, Denise; Kroese, Floor; Adriaanse, Marieke; Evers, Catharine

    2014-01-01

    Three experimental studies examined the counterintuitive hypothesis that hunger improves strategic decision making, arguing that people in a hot state are better able to make favorable decisions involving uncertain outcomes. Studies 1 and 2 demonstrated that participants with more hunger or greater appetite made more advantageous choices in the Iowa Gambling Task compared to sated participants or participants with a smaller appetite. Study 3 revealed that hungry participants were better able to appreciate future big rewards in a delay discounting task; and that, in spite of their perception of increased rewarding value of both food and monetary objects, hungry participants were not more inclined to take risks to get the object of their desire. Together, these studies for the first time provide evidence that hot states improve decision making under uncertain conditions, challenging the conventional conception of the detrimental role of impulsivity in decision making.

  7. The State of Food Security Report 2012 and the Enigma of Achieving Millennium Development Goals

    Directory of Open Access Journals (Sweden)

    Vikas Bajpai

    2013-07-01

    Full Text Available Globally quoted and unquestioningly accepted, the State of the Food Insecurity in the world report 2012, has made significant reduction in the numbers of hungry globally at 868 million. In case of India it has made significant upward revision of hunger prevalence in 1990-92 and significant downward revision for 2010 resulting in 34.9% estimated hunger decline. In the midst of claims of robust methodological revisions, its calculations and assumptions set a dangerous precedence for the policy-makers and planners of the reluctant country governments and worst for the hungry of the world. This paper discusses the SOFI 2012, critiques the declining hunger numbers in SOFI 2012 and produces alternate data sets including independent surveys of Government of India, to counter the reduction claims. It also makes a case for greater public dialogue and engagement in such reports, their methods, metrics and numbers.

  8. Hunger promotes acquisition of nonfood objects.

    Science.gov (United States)

    Xu, Alison Jing; Schwarz, Norbert; Wyer, Robert S

    2015-03-03

    Hunger motivates people to consume food, for which finding and acquiring food is a prerequisite. We test whether the acquisition component spills over to nonfood objects: Are hungry people more likely to acquire objects that cannot satisfy their hunger? Five laboratory and field studies show that hunger increases the accessibility of acquisition-related concepts and the intention to acquire not only food but also nonfood objects. Moreover, people act on this intention and acquire more nonfood objects (e.g., binder clips) when they are hungry, both when these items are freely available and when they must be paid for. However, hunger does not influence how much they like nonfood objects. We conclude that a basic biologically based motivation can affect substantively unrelated behaviors that cannot satisfy the motivation. This presumably occurs because hunger renders acquisition-related concepts and behaviors more accessible, which influences decisions in situations to which they can be applied.

  9. S.O.S Europa Faminta. Comitê de Socorro à Europa Faminta – SEF – (1946-1949

    Directory of Open Access Journals (Sweden)

    Evandro Fernandes

    2014-04-01

    This article analyzes the performance of the humanitarian aid organization called the Committee for Relief to the Hungry Europe, SEF, in the Brazilian context and internationally between the years 1946 and 1949. The analysis shows the importance of the aid agencies role for the reconstruction of Germany’s post-war in Brazil, it identifies the political and ideological motivations that caused the elites of the German ethnic group in the country to mobilize in favor of Germany as well as it highlights its role in the creation and articulation of the committee. The article identifies the difficulties faced by the Committee for Relief to the Hungry in the shipment of humanitarian aid to Europe, especially to Germany, as well as the social groups that have taken part in the collections, the articulation strategies of their leadership along with the power circles, the social and ideological function of the committee for the ethnic German community in Brazil.

  10. Clearing out a maze: A model of chemotactic motion in porous media

    Science.gov (United States)

    Schilling, Tanja; Voigtmann, Thomas

    2017-12-01

    We study the anomalous dynamics of a biased "hungry" (or "greedy") random walk on a percolating cluster. The model mimics chemotaxis in a porous medium: In close resemblance to the 1980s arcade game PAC-MA N ®, the hungry random walker consumes food, which is initially distributed in the maze, and biases its movement towards food-filled sites. We observe that the mean-squared displacement of the process follows a power law with an exponent that is different from previously known exponents describing passive or active microswimmer dynamics. The change in dynamics is well described by a dynamical exponent that depends continuously on the propensity to move towards food. It results in slower differential growth when compared to the unbiased random walk.

  11. Brain 'talks over' boring quotes: top-down activation of voice-selective areas while listening to monotonous direct speech quotations.

    Science.gov (United States)

    Yao, Bo; Belin, Pascal; Scheepers, Christoph

    2012-04-15

    In human communication, direct speech (e.g., Mary said, "I'm hungry") is perceived as more vivid than indirect speech (e.g., Mary said that she was hungry). This vividness distinction has previously been found to underlie silent reading of quotations: Using functional magnetic resonance imaging (fMRI), we found that direct speech elicited higher brain activity in the temporal voice areas (TVA) of the auditory cortex than indirect speech, consistent with an "inner voice" experience in reading direct speech. Here we show that listening to monotonously spoken direct versus indirect speech quotations also engenders differential TVA activity. This suggests that individuals engage in top-down simulations or imagery of enriched supra-segmental acoustic representations while listening to monotonous direct speech. The findings shed new light on the acoustic nature of the "inner voice" in understanding direct speech. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Optical Multidimensional Switching for Data Center Networks

    OpenAIRE

    Kamchevska, Valerija; Galili, Michael; Oxenløwe, Leif Katsuo; Berger, Michael Stübert

    2017-01-01

    Optical switches are known for the ability to provide high bandwidth connectivity at a relatively low power consumption and low latency. Several recent demonstrations on optical data center architectures confirm the potential for introducing all-optical switching within the data center, thus avoiding power hungry optical-electrical-optical conversions at each node. This Ph.D. thesis focuses precisely on the application of optical technologies in data center networks where optics is not only u...

  13. Social Protection for Enhanced Food Security in Sub-Saharan Africa

    OpenAIRE

    Stephen Devereux

    2012-01-01

    This paper identifies several positive synergies between social protection programmes and food security outcomes. One function of social protection is to manage and reduce vulnerability, and several instruments are reviewed – weather-indexed insurance, public works programmes, emergency food aid and buffer stock management – which all contribute to stabilising income and access to food across good and bad years, or between the harvest and the hungry season. Other social protection instruments...

  14. Ghrelin Signalling on Food Reward: A Salient Link Between the Gut and the Mesolimbic System

    OpenAIRE

    Perello, M.; Dickson, S. L.

    2015-01-01

    ?Hunger is the best spice? is an old and wise saying that acknowledges the fact that almost any food tastes better when we are hungry. The neurobiological underpinnings of this lore include activation of the brain's reward system and the stimulation of this system by the hunger?promoting hormone ghrelin. Ghrelin is produced largely from the stomach and levels are higher preprandially. The ghrelin receptor is expressed in many brain areas important for feeding control, including not only the h...

  15. Deprivation selectively modulates brain potentials to food pictures

    OpenAIRE

    Stockburger, Jessica; Weike, Almut I.; Hamm, Alfons O.; Schupp, Harald Thomas

    2008-01-01

    Event-related brain potentials (ERPs) were used to examine whether the processing of food pictures is selectively modulated by changes in the motivational state of the observer. Sixteen healthy male volunteers were tested twice 1 week apart, either after 24 hr of food deprivation or after normal food intake. ERPs were measured while participants viewed appetitive food pictures as well as standard emotional and neutral control pictures. Results show that the ERPs to food pictures in a hungry, ...

  16. Green IGP Link Weights for Energy-efficiency and Load-balancing in IP Backbone Networks

    OpenAIRE

    Francois, Frederic; Wang, Ning; Moessner, Klaus; Georgoulas, Stylianos; Xu, Ke

    2013-01-01

    The energy consumption of backbone networks has become a primary concern for network operators and regulators due to the pervasive deployment of wired backbone networks to meet the requirements of bandwidth-hungry applications. While traditional optimization of IGP link weights has been used in IP based load-balancing operations, in this paper we introduce a novel link weight setting algorithm, the Green Load-balancing Algorithm (GLA), which is able to jointly optimize both energy efficiency ...

  17. Discarding food vs. starving people: Inefficient and immoral?

    OpenAIRE

    Koester, Ulrich

    2012-01-01

    Intensive discussions about discarding food in recent weeks were prompted by a study commissioned by the German Bundestag and supported by the German Federal Ministry of Nutrition, Agriculture, and Consumer Protection. Spiegel online said on March 13, 2012: Europe's waste would suffice twice to feed the world's hungry. This statement startled many people. Food is discarded in Europe and other prosperous countries while many people in poor countries are starving. Hence, it seems that the globa...

  18. Hardware Support for Embedded Java

    DEFF Research Database (Denmark)

    Schoeberl, Martin

    2012-01-01

    The general Java runtime environment is resource hungry and unfriendly for real-time systems. To reduce the resource consumption of Java in embedded systems, direct hardware support of the language is a valuable option. Furthermore, an implementation of the Java virtual machine in hardware enables...... worst-case execution time analysis of Java programs. This chapter gives an overview of current approaches to hardware support for embedded and real-time Java....

  19. Profitable mining with the help of radiation technology

    International Nuclear Information System (INIS)

    Quevenco, Rodolfo

    2015-01-01

    During the boom years of the 2000s, the global mining industry expanded quickly, with many countries and companies investing large amounts of money in efforts to increase production and satisfy a rapidly growing global economy hungry for natural resources. Now, with lower commodity prices, decreasing ore quality and higher production costs, keeping these mines open means streamlining operations and improving productivity. Radiotracers and nucleonic gauges are among the techniques that enable the industry to achieve this increased efficiency.

  20. Přístupy k řešení problematiky hladu ve vybraných zemích subsaharské Afriky

    OpenAIRE

    Sommernitzová, Tereza

    2012-01-01

    This thesis discusses the methods of solving hunger in the two selected countries of Sub-Saharan Africa (Ghana, Burundi). Its aim is to introduce the various possibilities of solving the problem of hunger in the world and than comparing these two contrasting economies assess, whether the states use only the different methods of combating hunger, or not. The thesis also suggestes what the selected countries should focus on in the future in order to quickly reduce the number of hungry people. G...

  1. The Valjean Effect: Visceral States and Cheating

    OpenAIRE

    Williams, Elanor F.; Pizarro, David; Ariely, Dan; Weinberg, James D.

    2016-01-01

    Visceral states like thirst, hunger, and fatigue can alter motivations, predictions, and even memory. Across three studies, we demonstrate that such “hot” states can also shift moral standards and increase dishonest behavior. Compared to participants who had just eaten or who had not yet exercised, hungry and thirsty participants were more likely to behave dishonestly in order to win a prize. Consistent with the specificity of motivation that is characteristic of visceral states, participants...

  2. Big River Reservoir Project. Pawcatuck River and Narragansett Bay Drainage Basins. Water and Related Land Resources Study. Volume I. Main Report.

    Science.gov (United States)

    1981-07-01

    Reservoir (boating), Carr Pond (swimming, boating, trails), Phelps Pond ( swiming , picnicking), and Hungry and Harkney Hills (camping) would allow this...dredged from navigable waters. Eutrophic** Rich in nutritive matter. Fill Material*. Any pollutant used to create fill in the sense of replacing an...intermittent streams. Oligotrophlc**. Poor in nutritive matter. Plankton. The passively floating or swimming, usually minute animal and plant life, of a

  3. Who eats whom, when and why? Juvenile cannibalism in fish Asian seabass

    Directory of Open Access Journals (Sweden)

    Xiaojun Liu

    2017-01-01

    Full Text Available While juvenile cannibalism plays an important role in the evolution of organisms in natural populations, it is a serious problem in aquaculture. A number of genetic and environmental factors result in different rates of cannibalism. Whether there is kin recognition in juvenile cannibalism in fish is poorly understood. We studied cannibalism and kinship recognition in juveniles of Asian seabass using molecular parentage analysis with polymorphic microsatellites. In the three mass crosses, under an ordinary feeding scheme without size grading, the rate of juvenile loss due to cannibalism was 1.08% per day. In the group without feeding for 24 h, 2.30% ± 0.43% of offspring per day were lost within 24 h due to cannibalism. We detected that juveniles avoided cannibalizing their siblings when they were not hungry, whereas cannibalism among siblings increased when they were hungry. These data suggest that there is kin discrimination in fish cannibalism. Raising genetically closely related offspring in the same tanks and appropriate levels of feeding may reduce the rate of cannibalism. We hypothesized that the chemical cues for kin discrimination might be secreted by fish skins. To test this hypothesis, we analyzed gene expression profiles in the skins of juveniles under slightly and very hungry conditions using RNA sequencing and bioinformatics analysis. Genes differently expressed under slightly and very hungry conditions were identified. Among them, genes from the trypsin family were significantly down-regulated under starved conditions, suggesting that they may play a role in kin discrimination.

  4. JPRS Report, Near East & South Asia

    Science.gov (United States)

    1989-08-24

    no responsibility for the form, sufficiency, accuracy, genuineness, falsification or legal effect of any document.... Nor do they assume any...babies go hungry by depriving them of milk no longer disturbs them. Cries from the heart have never been a stumblingblock preventing the construction...complicated. They were tired of buying Algerian milk for babies in Oujda [Morocco] and at times paying for it in Moroccan currency. They openly expressed

  5. Enabling Energy-Efficient Advertising for Mobile Applications

    OpenAIRE

    Prochkova, Irena

    2013-01-01

    Advertisements are the main source of revenue for many free mobile applications, however, they increase the energy consumption of the mobile device. In particu- lar, the radio communication used for the advertisement data transfer is energy hungry, so advertisement sponsored applications (free) consume more energy than paid applications.In this thesis, we analyse the effect that advertisements have on the mobile device performance, especially, the energy consumption of transferring and displa...

  6. Filipinos in the Navy: Service, Interpersonal Relations, and Cultural Adaptation

    Science.gov (United States)

    1977-01-01

    self i:age involves racial identity. Not only do they make - heavy references to Malaysian , Filipino, Asian, and other labels with ethnic-racial...example, the responses in the various food categories elicited by the stimulus words HUNGRY and TO EAT reflect the main items of the group’s diet ...cultural groups’ diet . For example, the Korean group receives a high score for RICE, the U. S. group a very much lower score, and the Colombian group

  7. Kogi Truck Culture

    OpenAIRE

    Choy, Vivian

    2011-01-01

    Food trucks have become a large phenomenon in many parts of Southern California. In fact, the University of California, Los Angeles had begun permitting several food trucks to park on campus for hungry students, in response to the closure of the Bombshelter, a major campus food court. These trucks’ budding popularity has been spurred by the notable Kogi Trucks, which began its business serving those in Los Angeles. To explore the heart of this Kogi hype, I took two trips to the intersectio...

  8. Low Cost Silicon Coriolis' Gyroscope Paves the Way to Consumer IMU

    Science.gov (United States)

    Vigna, Benedetto; Pasolini, Fabio; de Nuccio, Roberto; Capovilla, Macro; Prandi, Luciano; Biganzoli, Fabio

    During the last two years MEMS linear accelerometers have reinvented the way of playing a game, protecting your sensitive data on HDD, using your mobile devices smartly or making your washing machine less power hungry. Consumer and Industrial Markets have taken advantage from "The MEMS Consumerization Wave", driven by STMicroelectronics, which introduced a wide portfolio of two and three-axis motion sensors meeting customer requirements in terms of size, performances, quality and price.

  9. Motherhood and the "Madness of Hunger": "...Want Almal Vra vir My vir 'n Stukkie Brood" ("...Because Everyone Asks Me for a Little Piece of Bread").

    Science.gov (United States)

    Kruger, Lou-Marié; Lourens, Marleen

    2016-03-01

    It is widely assumed that the social and economic conditions of poverty can be linked to common mental disorders in low-, middle- and high-income countries. Despite the considerable increase in quantitative studies investigating the link between poverty and mental health, the nature of the connection between poverty and emotional well-being/distress is still not fully comprehended. In this qualitative study, exploring how one group of Coloured South African women, diagnosed with depression and residing in a semi-rural low-income South African community, subjectively understand and experience their emotional distress, data was collected by means of in-depth semi-structured interviews and social constructionist grounded theory was used to analyse the data. We will attempt to show (1) that the depressed women in this group of respondents frequently refer to the emotional distress caused by hungry children and (2) that the emotional distress described by the respondents included emotions typically associated with depression (such as sadness, hopelessness and guilt), but also included emotions not necessarily associated with depression (such as anxiety, anger and anomie). In our attempt to understand (both psychologically and politically) the complex emotional response of mothers to their children's hunger, we argue that powerful gender and neo-liberal discourses within which mothers are interpellated to care for children, and more specifically, to make sure that children are not hungry, mean that the mothers of hungry children felt that they were not fulfilling their responsibilities and thus felt guilty and ashamed. This shame seemed, in turn, to lead to anger and/or anomie, informing acting out behaviours ranging from verbal and physical aggression to passive withdrawal. A vicious cycle of hunger, sadness and anxiety, shame, anger and anomie, aggression and withdrawal, negative judgement, and more shame, are thus maintained. As such, the unbearable rebukes of hungry

  10. Metabolic state alters economic decision making under risk in humans.

    OpenAIRE

    Mkael Symmonds; Julian J Emmanuel; Megan E Drew; Rachel L Batterham; Raymond J Dolan

    2010-01-01

    Background Animals' attitudes to risk are profoundly influenced by metabolic state (hunger and baseline energy stores). Specifically, animals often express a preference for risky (more variable) food sources when below a metabolic reference point (hungry), and safe (less variable) food sources when sated. Circulating hormones report the status of energy reserves and acute nutrient intake to widespread targets in the central nervous system that regulate feeding behaviour, including brain regio...

  11. Applications of Graph-Theoretic Tests to Online Change Detection

    Science.gov (United States)

    2014-05-09

    stock broker decides to sell a majority of his positions due to a change in the markets; a child grabs a snack because he has become hungry; an alarm...detected and the time when a negative result will occur (i.e. machine death through mechanical failure) or a positive chance squandered (not buying ...and moving low pressure systems in the atmosphere, and these systems cause persistence to daily rainfall. The daily weather in this area is a

  12. Unethical practices relating to cattle freedom, care and control ...

    African Journals Online (AJOL)

    In animal care, 40.0%, 31.3%, 30.0%, 12.5%, 7.5% and 5.0% were of the opinion that cattle could be respectively tired, hungry, sick, heady, injured and being in a strange environment might be the reasons for their refusal to obey the instruction of the handlers. In controlling the cattle for a direction, 85.7%, 10.4% and 3.9% ...

  13. Korean Affairs Report

    Science.gov (United States)

    1985-09-20

    Pyongyang station, the South Korean delegation boarded 16 Mercedes Benz sedans and seven buses, then headed for the Koryo Hotel. The South Korean...money-making, loudly advertising "relief of hungry children, "relief of the destitute" and "programme for the rebirth of narcotic addicts. It was with... market are twin pains these days. When they convert what they earned on the bearish stock exchange into dol- lars, their returns show minus gains

  14. Bureaucratic (?) Failures: Causes and Cures

    OpenAIRE

    Fiorina, Morris P.

    1982-01-01

    Bureaucracy is a traditional object of disparaging commentary, but in recent years it has received more than a proportionate share of popular and political criticism. Perceived problems of wasteful, unresponsive, power-hungry, and out-of-control bureaucracy have generated calls for across the board cut-backs in bureaucratic size and authority, as well as for various structural reforms designed to limit the activities of what is left after the pruning. This paper argues that much criticism of ...

  15. Application of Selective Algorithm for Effective Resource Provisioning in Cloud Computing Environment

    OpenAIRE

    Katyal, Mayanka; Mishra, Atul

    2014-01-01

    Modern day continued demand for resource hungry services and applications in IT sector has led to development of Cloud computing. Cloud computing environment involves high cost infrastructure on one hand and need high scale computational resources on the other hand. These resources need to be provisioned (allocation and scheduling) to the end users in most efficient manner so that the tremendous capabilities of cloud are utilized effectively and efficiently. In this paper we discuss a selecti...

  16. Incorporating solid state drives into distributed storage systems

    OpenAIRE

    Wacha, Rosie

    2012-01-01

    Big data stores are becoming increasingly important in a variety of domains including scientific computing, internet applications, and business applications. For price and performance reasons, such storage is comprised of magnetic hard drives. To achieve the necessary degree of performance and reliability, the drives are configured into storage subsystems based on RAID (Redundant Array of Independent Disks). Because of their mechanical nature, hard drives are relatively power-hungry and slow ...

  17. International trends in health science librarianship: Part 6 Central Europe series.

    Science.gov (United States)

    Viragos, Marta

    2013-06-01

    This is the 6th in a series of articles exploring international trends in health science librarianship with a focus on Central Europe in the first decade of the 21st century. The invited authors are from Hungry, Poland and Czech Republic. Future issues will track trends the Middle East and then the Far East. JM. © 2013 The authors. Health Information and Libraries Journal © 2013 Health Libraries Group.

  18. Recognition of a Baby's Emotional Cry Towards Robotics Baby Caregiver

    OpenAIRE

    Yamamoto, Shota; Yoshitomi, Yasunari; Tabuse, Masayoshi; Kushida, Kou; Asada, Taro

    2013-01-01

    We developed a method for pattern recognition of baby's emotions (discomfortable, hungry, or sleepy) expressed in the baby's cries. A 32-dimensional fast Fourier transform is performed for sound form clips, detected by our reported method and used as training data. The power of the sound form judged as a silent region is subtracted from each power of the frequency element. The power of each frequency element after the subtraction is treated as one of the elements of the feature vector. We per...

  19. Technology on the Horizon

    Science.gov (United States)

    Criswell, Chad

    2011-01-01

    Each day, dozens of new pieces of technology are released to gadget-hungry consumers. While many of these devices are geared toward the general public, a number of them are finding their way into the music classroom. Certain new products, such as the Apple iPad and iPod, have caused a major stir among music teachers of all grade levels and content…

  20. Heightened eating drive and visual food stimuli attenuate central nociceptive processing.

    Science.gov (United States)

    Wright, Hazel; Li, Xiaoyun; Fallon, Nicholas B; Giesbrecht, Timo; Thomas, Anna; Harrold, Joanne A; Halford, Jason C G; Stancak, Andrej

    2015-03-01

    Hunger and pain are basic drives that compete for a behavioral response when experienced together. To investigate the cortical processes underlying hunger-pain interactions, we manipulated participants' hunger and presented photographs of appetizing food or inedible objects in combination with painful laser stimuli. Fourteen healthy participants completed two EEG sessions: one after an overnight fast, the other following a large breakfast. Spatio-temporal patterns of cortical activation underlying the hunger-pain competition were explored with 128-channel EEG recordings and source dipole analysis of laser-evoked potentials (LEPs). We found that initial pain ratings were temporarily reduced when participants were hungry compared with fed. Source activity in parahippocampal gyrus was weaker when participants were hungry, and activations of operculo-insular cortex, anterior cingulate cortex, parahippocampal gyrus, and cerebellum were smaller in the context of appetitive food photographs than in that of inedible object photographs. Cortical processing of noxious stimuli in pain-related brain structures is reduced and pain temporarily attenuated when people are hungry or passively viewing food photographs, suggesting a possible interaction between the opposing motivational forces of the eating drive and pain. Copyright © 2015 the American Physiological Society.