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Akat E, Yenmiş M, Pombal MA, Molist P, Megías M, Arman S, Veselỳ M, Anderson R, Ayaz D. Comparison of Vertebrate Skin Structure at Class Level: A Review. Anat Rec (Hoboken) 2022; 305:3543-3608. [DOI: 10.1002/ar.24908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/14/2022] [Accepted: 02/21/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Esra Akat
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
| | - Melodi Yenmiş
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
| | - Manuel A. Pombal
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Pilar Molist
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Manuel Megías
- Universidade de Vigo, Departamento de Bioloxía Funcional e Ciencias da Saúde, Facultade de Bioloxía‐IBIV Vigo, España
| | - Sezgi Arman
- Sakarya University, Faculty of Science and Letters, Biology Department Sakarya Turkey
| | - Milan Veselỳ
- Palacky University, Faculty of Science, Department of Zoology Olomouc Czechia
| | - Rodolfo Anderson
- Departamento de Zoologia, Instituto de Biociências Universidade Estadual Paulista São Paulo Brazil
| | - Dinçer Ayaz
- Ege University, Faculty of Science, Biology Department Bornova, İzmir Turkey
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Heimroth RD, Casadei E, Benedicenti O, Amemiya CT, Muñoz P, Salinas I. The lungfish cocoon is a living tissue with antimicrobial functions. SCIENCE ADVANCES 2021; 7:eabj0829. [PMID: 34788085 PMCID: PMC8597997 DOI: 10.1126/sciadv.abj0829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 09/29/2021] [Indexed: 06/13/2023]
Abstract
Terrestrialization is an extreme physiological adaptation by which African lungfish survive dry seasons. For months and up to several years, lungfish live inside a dry mucus cocoon that protects them from desiccation. Light and electron microscopy reveal that the lungfish cocoon is a living tissue that traps bacteria. Transcriptomic analyses identify a global state of inflammation in the terrestrialized lungfish skin characterized by granulocyte recruitment. Recruited granulocytes transmigrate into the cocoon where they release extracellular traps. In vivo DNase I surface spraying during terrestrialization results in dysbiosis, septicemia, skin wounds, and hemorrhages. Thus, lungfish have evolved unique immunological adaptations to protect their bodies from infection for extended periods of time while living on land. Trapping bacteria outside their bodies may benefit estivating vertebrates that undergo metabolic torpor.
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Affiliation(s)
- Ryan Darby Heimroth
- Center for Evolutionary and Theoretical Immunology, Biology Department, University of New Mexico, Albuquerque, NM, USA
| | - Elisa Casadei
- Center for Evolutionary and Theoretical Immunology, Biology Department, University of New Mexico, Albuquerque, NM, USA
| | - Ottavia Benedicenti
- Center for Evolutionary and Theoretical Immunology, Biology Department, University of New Mexico, Albuquerque, NM, USA
| | - Chris Tsuyoshi Amemiya
- Department of Molecular and Cell Biology, University of California, Merced, Merced, CA, USA
| | - Pilar Muñoz
- Department of Animal Health, Campus de Espinardo, University of Murcia, 30100 Murcia, Spain
| | - Irene Salinas
- Center for Evolutionary and Theoretical Immunology, Biology Department, University of New Mexico, Albuquerque, NM, USA
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3
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Mailho‐Fontana PL, Titon B, Antoniazzi MM, Gomes FR, Jared C. Skin and poison glands in toads (
Rhinella
) and their role in defence and water balance. ACTA ZOOL-STOCKHOLM 2021. [DOI: 10.1111/azo.12390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
| | - Braz Titon
- Departamento de Fisiologia Geral Instituto de Biociências, Universidade de São Paulo São Paulo Brazil
| | | | - Fernando Ribeiro Gomes
- Departamento de Fisiologia Geral Instituto de Biociências, Universidade de São Paulo São Paulo Brazil
| | - Carlos Jared
- Laboratório de Biologia Estrutural Instituto Butantan São Paulo Brazil
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4
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The NOS/NO system in an example of extreme adaptation: The African lungfish. J Therm Biol 2020; 90:102594. [PMID: 32479389 DOI: 10.1016/j.jtherbio.2020.102594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 03/21/2020] [Accepted: 04/07/2020] [Indexed: 12/30/2022]
Abstract
African dipnoi (lungfish) are aestivating fish and obligate air breathers that, throughout their complex life cycle, undergo remarkable morpho-functional organ readjustment from biochemical to morphological level. In the present review we summarize the changes of the NOS/NO (Nitric Oxide Synthase/Nitric Oxide) system occurring in lungs, gills, kidney, heart, and myotomal muscle of African lungfish of the genus Protopterus (P. dolloi and P. annectens), in relation to the switch from freshwater to aestivation, and vice-versa. In particular, the expression and localization patterns of NOS, and its protein partners Akt, Hsp-90 and HIF-1α, have been discussed, together with the apoptosis rate, evaluated by TUNEL technique. We hypothesize that all these molecular components are crucial in signalling transduction/integration networks induced by environmental challenges (temperature, dehydration, inactivity)experienced at the beginning, during, and at the end of the dry season.
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5
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Ohmer MEB, Cramp RL, White CR, Harlow PS, McFadden MS, Merino-Viteri A, Pessier AP, Wu NC, Bishop PJ, Franklin CE. Phylogenetic investigation of skin sloughing rates in frogs: relationships with skin characteristics and disease-driven declines. Proc Biol Sci 2020; 286:20182378. [PMID: 30963925 DOI: 10.1098/rspb.2018.2378] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amphibian skin is highly variable in structure and function across anurans, and plays an important role in physiological homeostasis and immune defence. For example, skin sloughing has been shown to reduce pathogen loads on the skin, such as the lethal fungus Batrachochytrium dendrobatidis ( Bd), but interspecific variation in sloughing frequency is largely unknown. Using phylogenetic linear mixed models, we assessed the relationship between skin turnover rate, skin morphology, ecological traits and overall evidence of Bd-driven declines. We examined skin sloughing rates in 21 frog species from three continents, as well as structural skin characteristics measured from preserved specimens. We found that sloughing rate varies significantly with phylogenetic group, but was not associated with evidence of Bd-driven declines, or other skin characteristics examined. This is the first comparison of sloughing rate across a wide range of amphibian species, and creates the first database of amphibian sloughing behaviour. Given the strong phylogenetic signal observed in sloughing rate, approximate sloughing rates of related species may be predicted based on phylogenetic position. While not related to available evidence of declines, understanding variation in sloughing rate may help explain differences in the severity of infection in genera with relatively slow skin turnover rates (e.g. Atelopus).
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Affiliation(s)
- Michel E B Ohmer
- 1 School of Biological Sciences, The University of Queensland , St Lucia, Queensland 4072 , Australia.,2 Department of Biological Sciences, University of Pittsburgh , Pittsburgh, PA 15260 , USA
| | - Rebecca L Cramp
- 1 School of Biological Sciences, The University of Queensland , St Lucia, Queensland 4072 , Australia
| | - Craig R White
- 3 School of Biological Sciences, Monash University, Centre for Geometric Biology , Victoria 3800 , Australia
| | - Peter S Harlow
- 4 Taronga Conservation Society Australia, Herpetofauna Division , Mosman, New South Wales , Australia
| | - Michael S McFadden
- 4 Taronga Conservation Society Australia, Herpetofauna Division , Mosman, New South Wales , Australia
| | - Andrés Merino-Viteri
- 5 Laboratorio de Ecofisiología/Museo de Zoología (QCAZ), Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador , Quito , Ecuador
| | - Allan P Pessier
- 6 Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University , Pullman, WA 99164 , USA
| | - Nicholas C Wu
- 1 School of Biological Sciences, The University of Queensland , St Lucia, Queensland 4072 , Australia
| | - Phillip J Bishop
- 7 Department of Zoology, University of Otago , Dunedin , New Zealand
| | - Craig E Franklin
- 1 School of Biological Sciences, The University of Queensland , St Lucia, Queensland 4072 , Australia
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6
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Life history of frogs of the Brazilian semi‐arid (Caatinga), with emphasis in aestivation. ACTA ZOOL-STOCKHOLM 2019. [DOI: 10.1111/azo.12295] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Ge D, Lavidis N. Climatic modulation of neurotransmitter release in amphibian neuromuscular junctions: role of dynorphin-A. Am J Physiol Regul Integr Comp Physiol 2018; 314:R716-R723. [DOI: 10.1152/ajpregu.00263.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amphibian neuromuscular junctions (NMJs) become relatively more silent during the dry winter season in Australia. During the dry, calcium sensitivity is reduced, whereas calcium dependence remains unchanged. Endogenous opioid peptides play an important role in the regulation of the physiological functions of active and dormant vertebrates. Previous findings suggest that dynorphin-A is more potent than other opiates in decreasing evoked neurotransmission in amphibian NMJs. Dynorphin-A has been shown not to alter the amplitude or the frequency of miniature quantal neurotransmitter release. In the present study, we report that dynorphin-A exerted a more pronounced inhibitory effect on evoked neurotransmitter release during the dry (hibernating period) when compared with the wet (active period) season. Dynorphin-A increased the frequency and decreased the amplitude of miniature neurotransmitter release only at relatively high concentration during the dry season. In the present study, we propose that dynorphin-A suppresses evoked neurotransmitter release and thus contraction of skeletal muscles, while allowing subthreshold activation of the NMJ by miniature neurotransmission, thus preventing any significant neuromuscular remodeling. The inhibitory effect of dynorphin-A on evoked transmitter release is reduced by increasing the extracellular calcium concentration.
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Affiliation(s)
- Dengyun Ge
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Nickolas Lavidis
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, Australia
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8
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Bradshaw SD. A state of non-specific tension in living matter? Stress in Australian animals. Gen Comp Endocrinol 2017; 244:118-129. [PMID: 26449159 DOI: 10.1016/j.ygcen.2015.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 09/27/2015] [Accepted: 10/03/2015] [Indexed: 10/22/2022]
Abstract
Evidence of stress responses in Australian animals is reviewed through a series of case studies involving desert frogs and lizards, small carnivorous marsupials, desert wallabies, a dwarf kangaroo species, the quokka wallaby and a small nectarivorous bird. An operational definition of stress as "the physiological resultant of demands that exceed an animal's homeostatic capacities" is used to identify instances of stress responses in the field, and to gauge their intensity. Clear evidence of stress responses is found in small dasyurid marsupial carnivores, and desert agamid lizards, both of which are semelparous. Other instances of seasonal stress responses include the Rottnest Island quokka, the Barrow Island euro kangaroo and a small nectarivorous bird, the Silvereye. The review also highlights the high level of physiological adaptation of some desert wallabies, such as the Spectacled hare wallaby, which is able to maintain physiological homeostasis in the field when challenged by conditions of extreme drought. The importance of thermal and hygric refugia for the long-term survival or rock wallabies, which apparently lack any hormonal control of renal function, is also highlighted.
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Affiliation(s)
- S Don Bradshaw
- School of Animal Biology, The University of Western Australia, Perth, WA 6009, Australia.
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9
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Reilly BD, Franklin CE. Prevention of muscle wasting and osteoporosis: the value of examining novel animal models. J Exp Biol 2016; 219:2582-95. [DOI: 10.1242/jeb.128348] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ABSTRACT
Bone mass and skeletal muscle mass are controlled by factors such as genetics, diet and nutrition, growth factors and mechanical stimuli. Whereas increased mechanical loading of the musculoskeletal system stimulates an increase in the mass and strength of skeletal muscle and bone, reduced mechanical loading and disuse rapidly promote a decrease in musculoskeletal mass, strength and ultimately performance (i.e. muscle atrophy and osteoporosis). In stark contrast to artificially immobilised laboratory mammals, animals that experience natural, prolonged bouts of disuse and reduced mechanical loading, such as hibernating mammals and aestivating frogs, consistently exhibit limited or no change in musculoskeletal performance. What factors modulate skeletal muscle and bone mass, and what physiological and molecular mechanisms protect against losses of muscle and bone during dormancy and following arousal? Understanding the events that occur in different organisms that undergo natural periods of prolonged disuse and suffer negligible musculoskeletal deterioration could not only reveal novel regulatory factors but also might lead to new therapeutic options. Here, we review recent work from a diverse array of species that has revealed novel information regarding physiological and molecular mechanisms that dormant animals may use to conserve musculoskeletal mass despite prolonged inactivity. By highlighting some of the differences and similarities in musculoskeletal biology between vertebrates that experience disparate modes of dormancy, it is hoped that this Review will stimulate new insights and ideas for future studies regarding the regulation of atrophy and osteoporosis in both natural and clinical models of muscle and bone disuse.
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Affiliation(s)
- Beau D. Reilly
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Craig E. Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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10
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Reniers J, Brendonck L, Roberts JD, Verlinden W, Vanschoenwinkel B. Environmental harshness shapes life-history variation in an Australian temporary pool breeding frog: a skeletochronological approach. Oecologia 2015; 178:931-41. [PMID: 25694040 DOI: 10.1007/s00442-015-3258-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 01/29/2015] [Indexed: 01/29/2023]
Abstract
For many amphibians, high temperatures and limited precipitation are crucial habitat characteristics that limit species ranges and modulate life-history characteristics. Although knowledge of the ability of amphibians to cope with such environmental harshness is particularly relevant in the light of ongoing environmental change, relatively little is known about natural variation in age, maturation and associated life-history traits across species' ranges. We used the analysis of growth rings in bones to investigate the link between environmental harshness and life-history traits, including age and body size distribution, in specimens from 20 populations of the Australian bleating froglet, Crinia pseudinsignifera. Despite the short lifespan of the species, bone slides revealed geographic variation in average age, body size and reproductive investment linked to variation in temperature and rainfall. We found no difference in age at maturation in different climatic harshness regimes. Frogs from harsher environments invested less in their first reproductive event but grew older than their counterparts in more benign environments, thereby allowing for more reproductive events and buffering them against the increased chance of reproductive failure in the harsher environments. For individual frogs, climatic harshness experienced during an individual's life promoted larger body size. Overall, these results illustrate how bone structure analyses from preserved specimens allow both the testing of ecogeographic hypotheses and the assessment of the adaptive potential of species in the light of environmental change.
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Affiliation(s)
- Jane Reniers
- Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, Charles Deberiotstraat 32, 3000, Leuven, Belgium,
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11
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Reilly BD, Cramp RL, Franklin CE. Activity, abundance and expression of Ca2+-activated proteases in skeletal muscle of the aestivating frog, Cyclorana alboguttata. J Comp Physiol B 2014; 185:243-55. [DOI: 10.1007/s00360-014-0880-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 11/18/2014] [Accepted: 11/27/2014] [Indexed: 10/24/2022]
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12
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Faivovich J, Nicoli L, Blotto BL, Pereyra MO, Baldo D, Barrionuevo JS, Fabrezi M, Wild ER, Haddad CF. Big, Bad, and Beautiful: Phylogenetic Relationships of the Horned Frogs (Anura: Ceratophryidae). SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2014. [DOI: 10.2994/sajh-d-14-00032.1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Julián Faivovich
- División Herpetología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”—Consejo Nacional de Investigaciones Científicas y Técnicas, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina
| | - Laura Nicoli
- División Herpetología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”—Consejo Nacional de Investigaciones Científicas y Técnicas, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina
| | - Boris L. Blotto
- División Herpetología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”—Consejo Nacional de Investigaciones Científicas y Técnicas, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina
| | - Martín O. Pereyra
- División Herpetología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”—Consejo Nacional de Investigaciones Científicas y Técnicas, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina
| | - Diego Baldo
- Laboratorio de Genética Evolutiva, Instituto de Biología Subtropical (Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Misiones), Facultad de Ciencias Exactas Químicas y Naturales, Universidad Nacional de Misiones, N
| | - J. Sebastián Barrionuevo
- División Herpetología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”—Consejo Nacional de Investigaciones Científicas y Técnicas, Ángel Gallardo 470, C1405DJR, Buenos Aires, Argentina
| | - Marissa Fabrezi
- Instituto de Bio y Geociencias del NOA, Centro Científico Tecnológico-Salta, Consejo Nacional de Investigaciones Científicas y Técnicas, 9 de Julio 14, 4405, Rosario de Lerma, Salta, Argentina
| | - Erik R. Wild
- Department of Biology and Museum of Natural History, University of Wisconsin-Stevens Point. Stevens Point, Wisconsin, 54022, USA
| | - Célio F.B. Haddad
- Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, Avenida 24A1515, CEP 13506-900, Rio Claro, São Paulo, Brazil
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Cramp RL, McPhee RK, Meyer EA, Ohmer ME, Franklin CE. First line of defence: the role of sloughing in the regulation of cutaneous microbes in frogs. CONSERVATION PHYSIOLOGY 2014; 2:cou012. [PMID: 27293633 PMCID: PMC4806747 DOI: 10.1093/conphys/cou012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 05/22/2023]
Abstract
Amphibian populations worldwide are currently experiencing unprecedented declines due to the combined effects of emerging infectious disease and climate change. The skin is the first line of defence in preventing establishment of pathogens and associated infections. Although amphibians undergo regular sloughing of the outer layer of the skin, the potential for regular sloughing to play a role in influencing cutaneous microbial populations and pathogens has been largely overlooked. In the present study, we assessed the effect of skin sloughing on cultivable cutaneous bacterial abundance in the green tree frog (Litoria caerulea). We also examined the effects of temperature and hydric environment on sloughing frequency and microbial re-establishment rates. Our data showed that cultivable cutaneous bacterial abundance was significantly reduced by sloughing events, and frogs kept at 'summer' temperatures (23-33°C) sloughed almost twice as frequently as those maintained at 'winter' temperatures (13-23°C). No effect of hydric environment on sloughing frequency was observed, but we did find that sloughing in L. caerulea appeared to be linked to ambient light cycles. Examination of the effect of sloughing on microbial recolonization indicated that at cool temperatures, an extended intermoult interval allowed microbial abundance to reach higher levels than at warmer 'summer' temperatures (when the intermoult interval was significantly reduced). Our data suggest that sloughing may significantly influence the establishment and/or maintenance of cutaneous bacterial populations (pathogenic, mutualistic and/or commensal) and this, in turn, may be affected by environmental factors, such as ambient light and temperature. These findings are likely to be important for our understanding of the ecology of skin-based pathogens, such as the amphibian chytrid fungus, Batrachochytrium dendrobatidis.
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Affiliation(s)
- Rebecca L. Cramp
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Rebecca K. McPhee
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Edward A. Meyer
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Michel E. Ohmer
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Craig E. Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
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Larsen EH, Deaton LE, Onken H, O'Donnell M, Grosell M, Dantzler WH, Weihrauch D. Osmoregulation and Excretion. Compr Physiol 2014; 4:405-573. [DOI: 10.1002/cphy.c130004] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Tracy CR, Tixier T, Le Nöene C, Christian KA. Field hydration state varies among tropical frog species with different habitat use. Physiol Biochem Zool 2014; 87:197-202. [PMID: 24642537 DOI: 10.1086/674537] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We have previously shown that ecological habit (e.g., arboreal, terrestrial, amphibious) correlates with thermoregulatory behaviors and water balance physiology among species of hylid frogs in northern Australia. We hypothesized that these frogs would be different with respect to their field hydration states because of the challenges associated with the different ecological habits. There are very few data on the hydration levels that frogs maintain in the field, and the existing data are from disparate species and locations and do not relate hydration state to habit or changes in seasonal water availability. We measured the hydration state of 15 species of frogs from tropical northern Australia to determine the influences of ecological habit and season on the hydration state that these frogs maintain. As predicted, frogs were significantly less hydrated in the dry season than they were in the wet season and showed significantly higher variation among individuals, suggesting that maintaining hydration is more challenging in the dry season. In the wet season, terrestrial species were significantly less hydrated than arboreal or amphibious species. During the dry season, amphibious species that sought refuge in cracking mud after the pond dried were significantly less hydrated than terrestrial or arboreal species. These data suggest that hydration behaviors and voluntary tolerance of dehydration vary with habitat use, even within closely related species in the same family or genus. Terrestrial and arboreal species might be expected to be the most vulnerable to changes in water availability, because they are somewhat removed from water sources, but the physiological characteristics of arboreal frogs that result in significant cutaneous resistance to water loss allow them to reduce the effects of their dehydrating microenvironment.
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Affiliation(s)
- Christopher R Tracy
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory 0909, Australia; 2Department of Zoology, University of Melbourne, Parkville, Victoria 3010, Australia; 3Unité de Formation et de Recherche des Sciences et Techniques, Université Jean Monnet, 42023 Saint-Etienne Cedex 2, France
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Meyer EA, Cramp RL, Bernal MH, Franklin CE. Changes in cutaneous microbial abundance with sloughing: possible implications for infection and disease in amphibians. DISEASES OF AQUATIC ORGANISMS 2012; 101:235-242. [PMID: 23324420 DOI: 10.3354/dao02523] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The emergence of disease as a significant global threat to amphibian diversity has generated considerable interest in amphibian defenses against cutaneous microbial infection and disease. To date, however, the influence of sloughing on the susceptibility of amphibians to infection and disease has been largely overlooked. To investigate the potential for sloughing to regulate topical microbial loads, the abundance of cultivable cutaneous bacteria and fungi in the cane toad Rhinella marina were compared before and after sloughing. Toads were also exposed to fluctuating thermal regimes (10-20 and 20-30°C) and variable photoperiods to investigate possible effects of season and climate on sloughing periodicity. Sloughing substantially reduced the abundance of cultivable cutaneous bacteria and fungi by up to 100%. The intermoult interval of toads maintained at 10-20°C was twice that of animals at 20-30°C and did not appear to thermally acclimate. Photoperiod had no discernable influence on sloughing periodicity. Results of this study suggest that normal sloughing cycles could play a significant role in controlling the persistence and build-up of cutaneous microbes, including pathogens. The loss of non-pathogenic commensal and protective skin microbiota after sloughing may also influence host susceptibility to cutaneous pathogens. We suggest that the spatio-temporal dynamics of chytridiomycosis, the widespread and often fatal disease caused by the fungal pathogen Batrachochytrium dendrobatidis, are related to temperature not only because of its effect on the growth of the fungus, but also because of its effect on the frequency of host sloughing.
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Affiliation(s)
- Edward A Meyer
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia
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17
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Groom DJE, Kuchel L, Richards JG. Metabolic responses of the South American ornate horned frog (Ceratophrys ornata) to estivation. Comp Biochem Physiol B Biochem Mol Biol 2012; 164:2-9. [PMID: 22902863 DOI: 10.1016/j.cbpb.2012.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 08/01/2012] [Accepted: 08/01/2012] [Indexed: 01/15/2023]
Abstract
We examined the metabolic responses of the South American frog, Ceratophrys ornata, to laboratory-induced estivation. Whole-animal and mass-specific oxygen consumption rates (VO(2)) did not change during fasting or 56days of estivation, despite observing significant decreases in body mass. The maintenance of mass-specific metabolic rate at routine levels during estivation suggests that metabolic rate suppression is not a major response to estivation in this species. There was a significant decline in liver glycogen and a loss of adipose tissue mass during estivation, suggesting that both carbohydrate and lipid pathways are used to fuel metabolism during estivation. The activity of pyruvate dehydrogenase, an important regulator of carbohydrate oxidation, and carnitine palmitoyltransferase and 3-hydroxyacyl-CoA dehydrogenase, regulators of lipid oxidation, showed no significant change in activity in liver, heart, and muscle between estivating and active frogs. There was an increase in plasma osmolality, which is characteristic of estivating animals. Overall, our metabolic analysis of estivation in C. ornata indicates that this species does not employ a dramatic suppression metabolic rate to survive dehydration stress and that both endogenous carbohydrates and lipids are used as metabolic fuels.
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Affiliation(s)
- Derrick J E Groom
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada
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Reynolds SJ, Christian KA, Tracy CR, Hutley LB. Changes in body fluids of the cocooning fossorial frog Cyclorana australis in a seasonally dry environment. Comp Biochem Physiol A Mol Integr Physiol 2011; 160:348-54. [DOI: 10.1016/j.cbpa.2011.06.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 06/29/2011] [Accepted: 06/30/2011] [Indexed: 11/25/2022]
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Reynolds S, Christian K, Tracy C. The Cocoon of the Fossorial FrogCyclorana australisFunctions Primarily as a Barrier to Water Exchange with the Substrate. Physiol Biochem Zool 2010; 83:877-84. [DOI: 10.1086/656218] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Tracy CR, Christian KA, Tracy CR. Not just small, wet, and cold: effects of body size and skin resistance on thermoregulation and arboreality of frogs. Ecology 2010; 91:1477-84. [PMID: 20503879 DOI: 10.1890/09-0839.1] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We used simulations from a biophysical model that integrates interlinked exchanges of energy and water between frogs and their environments to address questions about the limits to thermoregulation and about adaptations for arboreality. Body size and cutaneous resistance (Rc) both significantly affected body temperature (Tb) and the time to desiccate to 70% of standard mass (an ecologically relevant metric of desiccation). Cutaneous resistances < 25 s/cm allow basking frogs to elevate their Tb several degrees above ambient, but Rc above 25 had little additional effect on Tb. Small frogs (<10 g) are able to elevate their Tb above ambient while basking, even with small Rc. Large frogs must have greater skin resistances to be able to elevate body temperatures above ambient, yet large frogs take longer to desiccate to 70% of their standard mass. Frogs can avoid rapid desiccation with high Rc, a large body size, or some combination of these traits. Our literature survey indicates that frogs with a combination of Rc and body size that would result in long times to desiccate to 70% of standard mass tend to be arboreal, suggesting that those species may be selectively favored in a niche that often requires frogs to be away from water sources for extended periods of time.
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Affiliation(s)
- Christopher R Tracy
- School of Environmental and Life Sciences, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
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Enzyme activity in the aestivating Green-striped burrowing frog (Cyclorana alboguttata). J Comp Physiol B 2010; 180:1033-43. [DOI: 10.1007/s00360-010-0471-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 03/11/2010] [Accepted: 03/13/2010] [Indexed: 10/19/2022]
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Titon B, Navas CA, Jim J, Gomes FR. Water balance and locomotor performance in three species of neotropical toads that differ in geographical distribution. Comp Biochem Physiol A Mol Integr Physiol 2010; 156:129-35. [PMID: 20096361 DOI: 10.1016/j.cbpa.2010.01.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 01/15/2010] [Accepted: 01/15/2010] [Indexed: 11/27/2022]
Abstract
Water availability in the environment is a fundamental factor in determining the limits of geographical distribution and the evolution of the physiological characters associated to water balance in anurans. In this paper, we compare some aspects of water balance and the sensitivity of locomotor performance to dehydration at different temperatures for three species of toads from the genus Rhinella, with different levels of dependence on forested environments. Results show patterns associated to interspecific differences in both geographical distribution and time of seasonal reproduction. Sensitivity of locomotor performance to dehydration was lower at low temperatures for R. icterica, the species that are reproductively active during winter and lower at intermediate temperatures for R. schneideri, the species that reproduces mostly during spring, suggesting a pattern of thermal adaptation of locomotor performance for these species. Otherwise, R. ornata, a species with broader reproductive season, shows high sensitivity of locomotor performance to dehydration at all temperatures tested, suggesting a stronger relation of breeding activity with patterns of rainfall than temperature variation. Furthermore, the low rates of water uptake of R. ornata may pose restrictions on the occupation of open areas by this species.
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Affiliation(s)
- Braz Titon
- Departamento de Fisiologia, Instituto de Biociências, Universidade Estadual Paulista, Campus Botucatu, Botucatu, SP, Brazil
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Tracy CR, Reynolds SJ, McArthur L, Tracy CR, Christian KA. Ecology of Aestivation in a Cocoon-forming Frog, Cyclorana Australis (Hylidae). COPEIA 2007. [DOI: 10.1643/0045-8511(2007)7[901:eoaiac]2.0.co;2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Role of calcium and vesicle-docking proteins in remobilising dormant neuromuscular junctions in desert frogs. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2007; 194:27-37. [DOI: 10.1007/s00359-007-0284-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2007] [Revised: 10/11/2007] [Accepted: 10/21/2007] [Indexed: 11/26/2022]
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Symonds BL, James RS, Franklin CE. Getting the jump on skeletal muscle disuse atrophy: preservation of contractile performance in aestivatingCyclorana alboguttata(Günther 1867). J Exp Biol 2007; 210:825-35. [PMID: 17297142 DOI: 10.1242/jeb.02711] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYProlonged immobilisation or unloading of skeletal muscle causes muscle disuse atrophy, which is characterised by a reduction in muscle cross-sectional area and compromised locomotory function. Animals that enter seasonal dormancy, such as hibernators and aestivators, provide an interesting model for investigating atrophy associated with disuse. Previous research on the amphibian aestivator Cyclorana alboguttata (Günther 1867)demonstrated an absence of muscle disuse atrophy after 3 months of aestivation, as measured by gastrocnemius muscle contractile properties and locomotor performance. In this study, we aimed to investigate the effect of aestivation on iliofibularis and sartorius muscle morphology and contractile function of C. alboguttata over a longer, more ecologically relevant time-frame of 9 months. We found that whole muscle mass, muscle cross-sectional area, fibre number and proportions of fibre types remained unchanged after prolonged disuse. There was a significant reduction in iliofibularis fibre cross-sectional area (declined by 36% for oxidative fibre area and 39% for glycolytic fibre area) and sartorius fibre density (declined by 44%). Prolonged aestivation had little effect on the isometric properties of the skeletal muscle of C. alboguttata. There was a significant reduction in the isometric contraction times of the relatively slow-twitch iliofibularis muscle, suggesting that the muscle was becoming slower after 9 months of aestivation (time to peak twitch increased by 25%, time from peak twitch to half relaxation increased by 34% and time from last stimulus to half tetanus relation increased by 20%). However, the results of the work-loop analysis clearly demonstrate that, despite changes to muscle morphology and isometric kinetics, the overall contractile performance and power output levels of muscles from 9-month aestivating C. alboguttata are maintained at control levels.
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Affiliation(s)
- Beth L Symonds
- School of Integrative Biology, The University of Queensland, St Lucia, Queensland 4072, Australia
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Abstract
Reproduction technologies for amphibians are increasingly used for the in vitro treatment of ovulation, spermiation, oocytes, eggs, sperm, and larvae. Recent advances in these reproduction technologies have been driven by (1) difficulties with achieving reliable reproduction of threatened species in captive breeding programs, (2) the need for the efficient reproduction of laboratory model species, and (3) the cost of maintaining increasing numbers of amphibian gene lines for both research and conservation. Many amphibians are particularly well suited to the use of reproduction technologies due to external fertilization and development. However, due to limitations in our knowledge of reproductive mechanisms, it is still necessary to reproduce many species in captivity by the simulation of natural reproductive cues. Recent advances in reproduction technologies for amphibians include improved hormonal induction of oocytes and sperm, storage of sperm and oocytes, artificial fertilization, and high-density rearing of larvae to metamorphosis. The storage of sperm in particular can both increase the security and reduce the cost of maintaining genetic diversity. It is possible to cryopreserve sperm for millennia, or store it unfrozen for weeks in refrigerators. The storage of sperm can enable multiple parentages of individual females' clutches of eggs and reduce the need to transport animals. Cryopreserved sperm can maintain the gene pool indefinitely, reduce the optimum number of males in captive breeding programs, and usher in new generations of Xenopus spp. germ lines for research. Improved in vitro fertilization using genetic diversity from stored sperm means that investigators need the oocytes from only a few females to produce genetically diverse progeny. In both research and captive breeding programs, it is necessary to provide suitable conditions for the rearing of large numbers of a diverse range of species. Compared with traditional systems, the raising of larvae at high densities has the potential to produce these large numbers of larvae in smaller spaces and to reduce costs.
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Affiliation(s)
- Robert K Browne
- Perth Zoo, 20 Labouchere Road, South Perth, Western Australia, 6151, Australia. robert.browne2gmail.com
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Cartledge VA, Withers PC, McMaster KA, Thompson GG, Bradshaw SD. Water balance of field-excavated aestivating Australian desert frogs, the cocoon-formingNeobatrachus aquiloniusand the non-cocooningNotaden nichollsi(Amphibia: Myobatrachidae). J Exp Biol 2006; 209:3309-21. [PMID: 16916967 DOI: 10.1242/jeb.02393] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYBurrowed aestivating frogs of the cocoon-forming species Neobatrachus aquilonius and the non-cocooning species Notaden nichollsi were excavated in the Gibson Desert of central Australia. Their hydration state(osmotic pressure of the plasma and urine) was compared to the moisture content and water potential of the surrounding soil. The non-cocooning N. nichollsi was consistently found in sand dunes. While this sand had favourable water potential properties for buried frogs, the considerable spatial and temporal variation in sand moisture meant that frogs were not always in positive water balance with respect to the surrounding soil. The cocoon-forming N. aquilonius was excavated from two distinct habitat types, a claypan in which frogs had a well-formed cocoon and a dune swale where frogs did not have a cocoon. Cocoons of excavated frogs ranged in thickness from 19.4 μm to 55.61 μm and consisted of 81-229 layers. Cocooned claypan N. aquilonius were nearing exhaustion of their bladder water reserves and had a urine osmolality approaching that of the plasma. By contrast, non-cocooned N. aquilonius from the dune swale were fully hydrated, although soil moisture levels were not as high as calculated to be necessary to maintain water balance. Both species had similar plasma arginine vasotocin (AVT) concentrations ranging from 9.4 to 164 pg ml-1, except for one cocooned N. aquilonius with a higher concentration of 394 pg ml-1. For both species, AVT showed no relationship with plasma osmolality over the lower range of plasma osmolalities but was appreciably increased at the highest osmolality recorded. This study provides the first evidence that cocoon formation following burrowing is not obligatory in species that are capable of doing so, but that cocoon formation occurs when soil water conditions are more desiccating than for non-cocooned frogs.
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Affiliation(s)
- Victoria A Cartledge
- Zoology, School of Animal Biology, MO92, University of Western Australia, Crawley, Western Australia 6009, Australia.
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Booth D. Effect of soil type on burrowing behavior and cocoon formation in the green-striped burrowing frog, Cyclorana alboguttata. CAN J ZOOL 2006. [DOI: 10.1139/z06-062] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the effect of soil type on burrowing behaviour and cocoon formation during aestivation in the green-striped burrowing frog, Cyclorana alboguttata (Günther, 1867). Given a choice, frogs always chose to burrow in wet sand in preference to wet clay. Frogs buried themselves faster and dug deeper burrows in sandy soil. However, under my laboratory conditions, there was little difference in the pattern of soil drying between the two soil types. Frogs in both sand and clay soil experienced hydrating conditions for the first 3 months and dehydrating conditions for the last 3 months of the 6-month aestivation period, and cocoons were not formed until after 3 months of aestivation. After 6 months, there were more layers in the cocoons of frogs aestivating in sand than those aestivating in clay. Frogs were able to absorb water from sandy soil with water potentials greater than –400 kPa, but lost water when placed on sand with a water potential of –1000 kPa.
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Affiliation(s)
- D.T. Booth
- School of Integrative Biology, The University of Queensland, Brisbane 4072, Australia
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Hudson NJ, Lehnert SA, Ingham AB, Symonds B, Franklin CE, Harper GS. Lessons from an estivating frog: sparing muscle protein despite starvation and disuse. Am J Physiol Regul Integr Comp Physiol 2006; 290:R836-43. [PMID: 16239372 DOI: 10.1152/ajpregu.00380.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long (6- to 9-mo) bouts of estivation in green-striped burrowing frogs lead to 28% atrophy of cruralis oxidative fibers ( P < 0.05) and some impairment of in vitro gastrocnemius endurance ( P < 0.05) but no significant deficit in maximal twitch force production. These data suggest the preferential atrophy of oxidative fibers at a rate slower than, but comparable to, laboratory disuse models. We tested the hypothesis that the frog limits atrophy by modulating oxidative stress. We assayed various proteins at the transcript level and verified these results for antioxidant enzymes at the biochemical level. Transcript data for NADH ubiquinone oxidoreductase subunit 1 (71% downregulated, P < 0.05) and ATP synthase (67% downregulated, P < 0.05) are consistent with mitochondrial quiescence and reduced oxidant production. Meanwhile, uncoupling protein type 2 transcription ( P = 0.31), which is thought to reduce mitochondrial leakage of reactive oxygen species, was maintained. Total antioxidant defense of water-soluble (22.3 ± 1.7 and 23.8 ± 1.5 μM/μg total protein in control and estivator, respectively, P = 0.53) and membrane-bound proteins (31.5 ± 1.9 and 42.1 ± 7.3 μM/μg total protein in control and estivator, respectively, P = 0.18) was maintained, equivalent to a bolstering of defense relative to oxygen insult. This probably decelerates muscle atrophy by preventing accumulation of oxidative damage in static protein reserves. Transcripts of the mitochondrially encoded antioxidant superoxide dismutase type 2 (67% downregulated, P < 0.05) paralleled mitochondrial activity, whereas nuclear-encoded catalase and glutathione peroxidase were maintained at control values ( P = 0.42 and P = 0.231), suggesting a dissonance between mitochondrial and nuclear antioxidant expression. Pyruvate dehydrogenase kinase 4 transcription was fourfold lower in estivators ( P = 0.11), implying that, in contrast to mammalian hibernators, this enzyme does not drive the combustion of lipids that helps spare hypometabolic muscle.
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Affiliation(s)
- Nicholas J Hudson
- Commonwealth Scientific and Industrial Research Organization Livestock Industries, 306 Carmody Rd., St. Lucia, Brisbane, Queensland 4072, Australia.
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Abstract
SUMMARYThe vertebrate integument represents an evolutionary compromise between the needs for mechanical protection and those of sensing the environment and regulating the exchange of materials and energy. Fibrous keratins evolved as a means of strengthening the integument while simultaneously providing a structural support for lipids, which comprise the principal barrier to cutaneous water efflux in terrestrial taxa. Whereas lipids are of fundamental importance to water barriers, the efficacy of these barriers depends in many cases on structural features that enhance or maintain the integrity of function. Amphibians are exceptional among tetrapods in having very little keratin and a thin stratum corneum. Thus, effective lipid barriers that are present in some specialized anurans living in xeric habitats are external to the epidermis, whereas lipid barriers of amniotes exist as a lipid-keratin complex within the stratum corneum. Amphibians prevent desiccation of the epidermis and underlying tissues either by evaporating water from a superficial aqueous film, which must be replenished, or by shielding the stratum corneum with superficial lipids. Water barrier function in vertebrates generally appears to be relatively fixed, although various species have`plasticity' to adjust the barrier effectiveness facultatively. While it is clear that both phenotypic plasticity and genetic adaptation can account for covariation between environment and skin resistance to water efflux, studies of the relative importance of these two phenomena are few. Fundamental mechanisms for adjusting the skin water barrier include changes in barrier thickness, composition and physicochemical properties of cutaneous lipids,and/or geometry of the barrier within the epidermis. While cutaneous lipids have been studied extensively in the contexts of disease and cosmetics,relatively little is known about the processes of permeability barrier ontogenesis related to adaptation and environment. Advances in such knowledge have didactic significance for understanding vertebrate evolution as well as practical application to clinical dermatology.
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Cartledge VA, Withers PC, Thompson GG, McMaster KA. Water relations of the burrowing sandhill frog, Arenophryne rotunda (Myobatrachidae). J Comp Physiol B 2005; 176:295-302. [PMID: 16315052 DOI: 10.1007/s00360-005-0051-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2005] [Revised: 10/17/2005] [Accepted: 10/26/2005] [Indexed: 10/25/2022]
Abstract
Arenophryne rotunda is a small (2-8 g) terrestrial frog that inhabits the coastal sand dunes of central Western Australia. While sand burrowing is a strategy employed by many frog species inhabiting Australia's semi-arid and arid zones, A. rotunda is unique among burrowing species because it lives independently of free water and can be found nocturnally active on the dune surface for relatively extended periods. Consequently, we examined the physiological factors that enable this unique frog to maintain water balance. A. rotunda was not found to have any special adaptation to reduce EWL (being equivalent to a free water surface) or rehydrate from water (having the lowest rehydration rate measured for 15 Western Australian frog species), but it was able to maintain water balance in sand of very low moisture (1-2%). Frogs excavated in the field were in dune sand of 4.4% moisture content, as a consequence of recent rain, which was more than adequate for these frogs to maintain water balance as reflected by their low plasma and urine osmotic concentrations. We suggest that in dry periods of the year, A. rotunda can achieve positive water balance by cutaneous water uptake by burrowing deeper into the substrate to where the percent water content is greater than 1.5%.
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Affiliation(s)
- V A Cartledge
- Zoology, School of Animal Biology, MO92, University of Western Australia, 6009, Crawley, WA, Australia.
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Young JE, Christian KA, Donnellan S, Tracy CR, Parry D. Comparative analysis of cutaneous evaporative water loss in frogs demonstrates correlation with ecological habits. Physiol Biochem Zool 2005; 78:847-56. [PMID: 16052451 DOI: 10.1086/432152] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2004] [Indexed: 11/03/2022]
Abstract
Most frog species show little resistance to evaporative water loss (EWL), but some arboreal species are known to have very high resistances. We measured EWL and cutaneous resistance to evaporation (Rc) in 25 species of frogs from northern Australia, including 17 species in the family Hylidae, six species in the Myobatrachidae, and one each in the Bufonidae and the Microhylidae. These species display a variety of ecological habits, including aquatic, terrestrial, and arboreal specialisations, with the complete range of habits displayed within just the one hylid genus, Litoria. The 25 species measured in this study have resistances that range from Rc=0 to 63.1. These include low values indistinguishable from a free water surface to high values typical of "waterproof" anuran species. There was a strong correlation between ecological habit and Rc, even taking phylogenetic relationships into account; arboreal species had the highest resistance, aquatic species tended to have little or no resistance, and terrestrial species tended to have resistance between those of arboreal and aquatic frogs. For one species, Litoria rubella, we found no significant changes in EWL along a 1,500-km aridity gradient. This study represents the strongest evidence to date of a link between ecological habits and cutaneous resistance to water loss among species of frogs.
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Affiliation(s)
- Jeanne E Young
- School of Science, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
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Shalan AG, Bradshaw SD, Withers PC, Thompson G, Bayomy MFF, Bradshaw FJ, Stewart T. Spermatogenesis and plasma testosterone levels in Western Australian burrowing desert frogs, Cyclorana platycephala, Cyclorana maini, and Neobatrachus sutor, during aestivation. Gen Comp Endocrinol 2004; 136:90-100. [PMID: 14980800 DOI: 10.1016/j.ygcen.2003.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Revised: 12/09/2003] [Accepted: 12/09/2003] [Indexed: 10/26/2022]
Abstract
Changes in testis size, histological status, and plasma levels of testosterone were monitored for males of three species of Western Australian desert frogs, Cyclorana maini, Cyclorana platycephala, and Neobatrachus sutor during aestivation. The frogs were induced to burrow and form cocoons soon after their capture and then disinterred at intervals in order to monitor changes in reproductive activity of the testes. All stages of spermatogenesis were evident in active frogs, which were collected a few days following rain from breeding choruses. Relative testis mass declined gradually in all species during the first 7 months of aestivation and then increased significantly at 16-19 months in the two species for which extended data were available (C. maini and N. sutor). A decrease in the number of sperm bundles 2-4 months after cocooning was associated with an initial increase in the number of free spermatazoa in all three species, which then returned to the levels seen in active animals after 7 months. Increases in the number of primary and secondary spermatogonia were most evident in C. platycephala after 4-7 months of aestivation, but early stages of spermatocytogenesis were evident in all species after 7 months of aestivation, especially in individuals that contained neither sperm bundles nor mature spermatazoa. Changes in plasma testosterone levels correlated significantly with variations in the diameter of the seminiferous tubules and the GSI, suggesting that this hormone plays a major role in controlling testicular recrudescence in aestivating, cocooned, desert frogs. Data from this study show that, in the absence of any external cues, testicular recrudescence is evident after approximately one year of aestivation in desert frogs which prepares them to breed again, once rain falls.
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Affiliation(s)
- A G Shalan
- School of Animal Biology and Centre for Native Animal Research, The University of Western Australia, Perth, WA 6009, Australia
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Bayomy MFF, Shalan AG, Bradshaw SD, Withers PC, Stewart T, Thompson G. Water content, body weight and acid mucopolysaccharides, hyaluronidase and beta-glucuronidase in response to aestivation in Australian desert frogs. Comp Biochem Physiol A Mol Integr Physiol 2002; 131:881-92. [PMID: 11897199 DOI: 10.1016/s1095-6433(02)00004-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study investigates the effects of aestivation on body water content, body mass, acid mucopolysaccharide (AMPS) and some of its degrading enzymes in different tissues for some Australian desert frogs. The AMPS component of the liver, kidney, skin and cocoon alter during aestivation to help retain water, which is unchanged in most tissues of all frog species, and to protect the frogs from desiccation during extended periods of aestivation. Hepatic AMPS was unaltered in Cyclorana maini, C. platycephala and Neobatrachus sutor but increased significantly after 2 months of aestivation in C. australis. The level of AMPS in the kidney was elevated in all four frog species after 5 months of aestivation. Skin AMPS content in the skin of awake frogs decreases with aestivation period and increases in the cocoon. AMPS in the cocoon probably works as a cement between the cocoons' layers and its physical presence presumably contributes to preventing water flux. Changes in AMPS content in different tissues were accompanied by significant changes in both hyaluronidase and beta-glucuronidase activities, which play an important role in AMPS metabolism. Alcian blue staining of control and digested skin of C. australis and C. platycephala with testicular hyaluronidase indicated the presence of AMPS, concentrated in a thin layer (called ground substance, GS) located between stratum compactum and stratum spongiosum, and acid mucin concentrated in the mucous glands and in a 'tubular' structure which could be observed in the epidermal layer. Hyaluronidase digestion of the cocoon slightly changed the Alcian Blue colour, suggesting the presence of a large amount of acid mucin similar to that found in the skin mucous gland. The results of this study present data for the redistribution of AMPS, which may help in reducing water loss across the cocoon and reabsorption of water in the kidney during aestivation.
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Affiliation(s)
- M F F Bayomy
- Department of Zoology, Faculty of Science, Menoufia University, Shiben El-Kom, Egypt.
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Withers PC, Hillman SS. Allometric and ecological relationships of ventricle and liver mass in anuran amphibians. Funct Ecol 2001. [DOI: 10.1046/j.1365-2435.2001.00495.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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