Osmoregulation in Amphibians and Reptiles

Shoemaker, Vaughan H.; Nagy, Kenneth A.

doi:10.1146/annurev.ph.39.030177.002313

Cited by 261 publications

(136 citation statements)

References 56 publications

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“…Numerous species of fishes, birds, reptiles, marine mammals and some amphibians perform annual migrations or dispersions in which they are subject to large changes in the salinity of their environment. Osmoregulation is a major physiological challenge for these vertebrates (Peaker and Linzell, 1975;Skadhauge, 1981;Sabat, 2000;Bentley, 2002), and most of them possess the ability to osmoregulate in dynamic environments by means of physiological and behavioural adaptations (SchmidtNielsen, 1960;Peaker and Linzell, 1975;Shoemaker and Nagy, 1977;Shuttleworth and Hildebrandt, 1999;Sabat, 2000;Hildebrandt, 2001;Ortiz, 2001;Bentley, 2002). Apart from kidneys, nonmammalian vertebrates possess accessory organs (e.g.…”

Section: Introductionmentioning

confidence: 99%

Understanding the energetic costs of living in saline environments: effects of salinity on basal metabolic rate, body mass and daily energy consumption of a long-distance migratory shorebird

Gutiérrez

Masero

Abad‐Gómez

et al. 2011

Journal of Experimental Biology

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SUMMARYMany migratory vertebrates typically move between habitats with varying salinities during the annual cycle. These organisms clearly exhibit a remarkable phenotypic flexibility in their 'osmoregulatory machinery', but the metabolic consequences of salinity acclimatization are still not well understood. We investigated the effects of salinity on basal metabolic rate (BMR), body mass and daily energy consumption of a long-distance migratory shorebird, the dunlin (Calidris alpina), outside the breeding season. Masscorrected BMR and daily energy consumption increased significantly by 17 and 20% between freshwater (0.3‰ NaCl) and saltwater (33.0-35.0‰ NaCl), respectively. Body mass in both captive and wild dunlins was lower (9-16%) in saline than in freshwater environments. These changes on BMR and body mass were quickly reversed by returning the birds to freshwater, suggesting that metabolic adjustment to saltwater and metabolic readjustment to freshwater are both processes that occur in a few days. Our findings support empirically that the processes of developing and maintaining an active osmoregulatory machinery are energetically expensive, and they could help to explain diet and/or habitat selection patterns along the flyway. Finally, we discuss whether body mass loss in saltwater may be a strategy to reduce maintenance cost in osmotically stressful conditions such as overwintering in marine habitats, and raise some methodological implications for studies of BMR-related outcomes using captive birds captured in saline environments.

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Section: Introductionmentioning

confidence: 99%

Understanding the energetic costs of living in saline environments: effects of salinity on basal metabolic rate, body mass and daily energy consumption of a long-distance migratory shorebird

Gutiérrez

Masero

Abad‐Gómez

et al. 2011

Journal of Experimental Biology

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“…There have been many studies of the ways in which frogs are able to survive quite inhospitable environments (for reviews, see Deyrup, 1964;Bentley, 1966;Heatwole, 1984;Toledo and Jared, 1993). Most frogs have not developed a resistance to cutaneous water loss (Bentley, 1966;Shoemaker and Nagy, 1977;Toledo and Jared, 1993), probably because of the importance of a moist skin in respiration (Chew, 1961). There are, however, important exceptions.…”

Section: Introductionmentioning

confidence: 99%

Lipid-reduced evaporative water loss in two arboreal hylid frogs

Amey

Grigg

1995

Comparative Biochemistry and Physiology Part A: Physiology

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Rates of evaporative water loss were measured in seven species of Australian frogs from different habitats and compared with agar replicas. The two arboreal species, Litoria fallax and Litoria peroni, showed a marked resistance to water loss, and each has a cutaneous lipid layer which appears to provide the waterproofing mechanism. Rates of water loss were compared between Litoria peroni and one of the other species, Limnodynastes fletcheri, at 20, 25, 35 and 40°C. Even at the highest temperatures, Litoria peroni maintained its resistance to water loss, implying no attempt at thermoregulation by evaporative cooling.

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“…The skin of amphibians is highly permeable, and regulates water uptake, salt balance (Greenwald, 1971;Shoemaker and Nagy, 1977) and gas exchange during normal and hypoxic conditions (West and Burggren, 1984;Boutilier et al, 1986;Pinder and Burggren, 1986). Owing to their highly permeable skin, amphibians have a high susceptibility to evaporative water loss.…”

Section: Discussionmentioning

confidence: 99%

Regulation of theRana sylvaticabrevinin-1SY antimicrobial peptide during development and in dorsal and ventral skin in response to freezing, anoxia, and dehydration

Katzenback

Holden

Falardeau

et al. 2014

Journal of Experimental Biology

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Brevinin-1SY is the only described antimicrobial peptide (AMP) of Rana sylvatica. As AMPs are important innate immune molecules that inhibit microbes, this study examined brevinin-1SY regulation during development and in adult frogs in response to environmental stress. The brevinin-1SY nucleotide sequence was identified and used for protein modeling. Brevinin-1SY was predicted to be an amphipathic, hydrophobic, alpha helical peptide that inserts into a lipid bilayer. Brevinin-1SY transcripts were detected in tadpoles and were significantly increased during the later stages of development. Effects of environmental stress (24 h anoxia, 40% dehydration or 24 h frozen) on the mRNA levels of brevinin-1SY in the dorsal and ventral skin were examined. The brevinin-1SY mRNA levels were increased in dorsal and ventral skin of dehydrated frogs, and in ventral skin of anoxic frogs, compared with controls (non-stressed). Brevinin-1SY protein levels in peptide extracts of dorsal skin showed a similar, but not significant, trend to that of brevinin-1SY mRNA levels. Antimicrobial activity of skin extracts from control and stressed animals were assessed for Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae, Botrytis cinerea, Rhizopus stolonifer and Pythium sulcatum using disk diffusion assays. Peptide extracts of dorsal skin from anoxic, frozen and dehydrated animals showed significantly higher inhibition of E. coli and P. sulcatum than from control animals. In ventral skin peptide extracts, significant growth inhibition was observed in frozen animals for E. coli and P. sulcatum, and in anoxic animals for B. cinerea, compared with controls. Environmental regulation of brevinin-1SY may have important implications for defense against pathogens.

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Osmoregulation in Amphibians and Reptiles

Cited by 261 publications

References 56 publications

Understanding the energetic costs of living in saline environments: effects of salinity on basal metabolic rate, body mass and daily energy consumption of a long-distance migratory shorebird

Understanding the energetic costs of living in saline environments: effects of salinity on basal metabolic rate, body mass and daily energy consumption of a long-distance migratory shorebird

Lipid-reduced evaporative water loss in two arboreal hylid frogs

Regulation of theRana sylvaticabrevinin-1SY antimicrobial peptide during development and in dorsal and ventral skin in response to freezing, anoxia, and dehydration

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