Antimicrobial peptide defenses of the mountain yellow-legged frog (Rana muscosa)

Rollins‐Smith, Louise A.; Woodhams, Douglas C.; Reinert, Laura K.; Vredenburg, Vance T.; Briggs, Cheryl J.; Nielsen, Per F.; Conlon, J. Michael

doi:10.1016/j.dci.2005.10.005

Cited by 98 publications

(73 citation statements)

References 43 publications

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“…First, the reduced susceptibility of frogs from persistent populations could be an outcome of natural selection (36) on R. sierrae that occurred after the arrival of Bd in Yosemite's frog populations, selection to which the naïve frog populations would not have been subject. For example, if the initial invasion of Bd into Yosemite decades ago resulted in high levels of frog mortality, then the remaining populations may be descendants of individuals that possessed more effective innate or adaptive defenses against Bd (35,37). Second, the lower susceptibility could be the result of an acquired immune response in frogs from persistent populations after their exposure to Bd in the wild, a response that itself could be subject to natural selection.…”

Section: Resultsmentioning

confidence: 99%

Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors

Knapp¹,

Fellers

Kleeman

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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129

118

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Amphibians are one of the most threatened animal groups, with 32% of species at risk for extinction. Given this imperiled status, is the disappearance of a large fraction of the Earth's amphibians inevitable, or are some declining species more resilient than is generally assumed? We address this question in a species that is emblematic of many declining amphibians, the endangered Sierra Nevada yellowlegged frog (Rana sierrae). Based on >7,000 frog surveys conducted across Yosemite National Park over a 20-y period, we show that, after decades of decline and despite ongoing exposure to multiple stressors, including introduced fish, the recently emerged disease chytridiomycosis, and pesticides, R. sierrae abundance increased sevenfold during the study and at a rate of 11% per year. These increases occurred in hundreds of populations throughout Yosemite, providing a rare example of amphibian recovery at an ecologically relevant spatial scale. Results from a laboratory experiment indicate that these increases may be in part because of reduced frog susceptibility to chytridiomycosis. The disappearance of nonnative fish from numerous water bodies after cessation of stocking also contributed to the recovery. The large-scale increases in R. sierrae abundance that we document suggest that, when habitats are relatively intact and stressors are reduced in their importance by active management or species' adaptive responses, declines of some amphibians may be partially reversible, at least at a regional scale. Other studies conducted over similarly large temporal and spatial scales are critically needed to provide insight and generality about the reversibility of amphibian declines at a global scale.amphibians | recovery | disease | Rana sierrae | Yosemite

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Section: Resultsmentioning

confidence: 99%

Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors

Knapp¹,

Fellers

Kleeman

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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129

118

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“…Under this scenario, Bd growth rates do in fact decline with temperature as predicted but do not translate into the expected reduced infection intensities on frogs because both the innate and acquired immune systems of amphibians are less effective at these low temperatures (Carey et al 1999). For example, amphibians, including mountain yellow-legged frogs, produce a wide variety of antimicrobial skin peptides that strongly suppress the growth of Bd (Rollins-Smith et al 2002, Rollins-Smith et al 2006) but production of these peptides is greatly reduced at low temperatures (Matutte et al 2000, Ribas et al 2009. Similarly, proliferation of T lymphocytes is much lower at cold temperatures than at higher temperatures (Maniero and Carey 1997).…”

Section: Predictive Failure Of the Temperature-bd Growth Relationshipmentioning

confidence: 99%

Nowhere to hide: impact of a temperature-sensitive amphibian pathogen along an elevation gradient in the temperate zone

Knapp¹,

Briggs

Smith

et al. 2011

Ecosphere

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Abstract. Amphibians are rapidly disappearing from habitats around the world and a major cause of these declines is the amphibian chytrid fungus, Batrachochytrium dendrobatidis (''Bd''). The growth rate of Bd is strongly temperature-dependent, and in areas where temperatures are well outside the envelope in which Bd has high growth rates, amphibians may be afforded a refuge from the effects of Bd. This possibility has received considerable empirical support in hot climates, but remains largely untested in cold climates. We conducted a five-year study of the impact of Bd on the declining Sierra Nevada yellow-legged frog (Rana sierrae) across an elevation/temperature gradient in Yosemite National Park using three approaches: (1) resurveys of all 285 R. sierrae populations to describe the landscape-scale patterns of Bd infection intensity, frog population size, and frog population persistence; (2) detailed description of seasonal patterns in temperatures and corresponding Bd infection intensities on R. sierrae; and (3) a frog translocation experiment in which infected R. sierrae from a single source lake were introduced into each of five lakes along an elevation gradient. We predicted that infection intensity should decrease with increasing elevation (i.e., decreasing temperature), and consequently frog survival, population size, and population persistence should increase with elevation. Results from resurveys indicated that frog population size increased with elevation but Bd infection intensity and frog population persistence were unrelated to elevation. Seasonal temperatures varied widely but had no significant effect on Bd infection intensity. Results from the translocation experiment indicated that Bd infection intensity and frog survival following translocation were also unrelated to water temperature. Therefore, contrary to the widely-accepted paradigm that cold environments should strongly limit effects of Bd on amphibians, we found little or no evidence of such limitation at even the highest elevations. Therefore, in temperate montane ecosystems it is unlikely that high elevations will provide amphibians with a refuge from Bd.

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“…Therefore, measurements of skin peptides reflect the most recent peptide release, which is influenced by sensitivity to noradrenaline as well as by the amount of peptides that are stored in the glands. Hydrophobic peptides were collected onto C-18 Sep-Pak cartridges (Waters Corporation, Milford, MA, USA) (Ramsey et al, 2010) and then eluted in elution buffer containing 70% acetonitrile, 29.9% water and 0.1% TFA (Rollins-Smith et al, 2006). Concentrations of peptides were determined using Micro BCA analysis (Pierce, Rockford, IL, USA) following the manufacturer's instructions, with the exception that bradykinin was used to establish a standard curve (Rollins-Smith et al, 2006).…”

Section: Skin Peptide Collectionmentioning

confidence: 99%

Interactive effects of competition and predator cues on immune responses of leopard frogs at metamorphosis

Groner

Rollins‐Smith

Reinert

et al. 2013

Journal of Experimental Biology

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Recent hypotheses suggest that immunosuppression, resulting from altered environmental conditions, may contribute to the increased incidence of amphibian disease around the world. Antimicrobial peptides (AMPs) in amphibian skin are an important innate immune defense against fungal, viral and bacterial pathogens. Their release is tightly coupled with release of the stress hormone noradrenaline (norepinephrine). During metamorphosis, AMPs may constitute the primary immune response in the skin of some species because acquired immune functions are temporarily suppressed in order to prevent autoimmunity against new adult antigens. Suppression of AMPs during this transitional stage may impact disease rates. We exposed leopard frog tadpoles (Lithobates pipiens) to a factorial combination of competitor and caged-predator environments and measured their development, growth and production of hydrophobic skin peptides after metamorphosis. In the absence of predator cues, or if the exposure to predator cues was late in ontogeny, competition caused more than a 250% increase in mass-standardized hydrophobic skin peptides. Predator cues caused a decrease in mass-standardized hydrophobic skin peptides when the exposure was late in ontogeny under low competition, but otherwise had no effect. Liquid chromatography tandem mass spectrometry of the skin peptides showed that they include six AMPs in the brevinin and temporin families and at least three of these peptides are previously uncharacterized. Both of these peptide families have previously been shown to inhibit harmful microbes including Batrachochytrium dendrobatidis, the fungal pathogen associated with global amphibian declines. Our study shows that amphibians may be able to adjust their skin peptide defenses in response to stressors that are experienced early in ontogeny and that these effects extend through an important life-history transition.

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Antimicrobial peptide defenses of the mountain yellow-legged frog (Rana muscosa)

Cited by 98 publications

References 43 publications

Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors

Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors

Nowhere to hide: impact of a temperature-sensitive amphibian pathogen along an elevation gradient in the temperate zone

Interactive effects of competition and predator cues on immune responses of leopard frogs at metamorphosis

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