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Vaziri GJ, Reid NM, Rittenhouse TAG, Bolnick DI. Winter break? The effect of overwintering on immune gene expression in wood frogs. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2024; 52:101296. [PMID: 39096759 DOI: 10.1016/j.cbd.2024.101296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 07/18/2024] [Accepted: 07/18/2024] [Indexed: 08/05/2024]
Abstract
Among terrestrial ectotherms, hibernation is a common response to extreme cold temperatures and is associated with reduced physiological rates, including immunity. When winter wanes and temperatures increase, so too do vital rates of both ectothermic hosts and their parasites. Due to metabolic scaling, if parasite activity springs back faster than host immune functions then cold seasons and transitions between cold and warm seasons may represent periods of vulnerability for ectothermic hosts. Understanding host regulation of physiological rates at seasonal junctions is a first step toward identifying thermal mismatches between hosts and parasites. Here we show that immune gene expression is responsive to transitions into and out of the cold season in a winter-adapted amphibian, the wood frog (Lithobates sylvaticus), and that frogs experienced parasitism by at least two nematode species throughout the entirety of the cold season. In both splenic and skin tissues, we observed a decrease in immune gene expression going from fall to winter, observed no changes between winter and emergence from hibernation, and observed increases in immune gene expression after hibernation ended. At all timepoints, differentially expressed genes from spleens were more highly enriched for immune system processes than those from ventral skin, especially with respect to terms related to adaptive immune processes. Infection with nematode lungworms was also associated with upregulation of immune processes in the spleen. We suggest that rather than being a period of stagnation, during which physiological processes and infection potential cease, the cold season is immunologically dynamic, requiring coordinated regulation of many biological processes, and that the reemergence period may be an important time during which hosts invest in preparatory immunity.
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Affiliation(s)
- Grace J Vaziri
- University of Connecticut, Department of Ecology and Evolutionary Biology, Storrs, CT, 06269, USA.
| | - Noah M Reid
- University of Connecticut, Institute for Systems Genomics, Storrs, CT, 06269, USA
| | - Tracy A G Rittenhouse
- University of Connecticut, Department of Natural Resources and the Environment, Storrs, CT, 06269, CT, USA
| | - Daniel I Bolnick
- University of Connecticut, Department of Ecology and Evolutionary Biology, Storrs, CT, 06269, USA
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2
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Viblanc VA, Criscuolo F, Sosa S, Schull Q, Boonstra R, Saraux C, Lejeune M, Roth JD, Uhlrich P, Zahn S, Dobson FS. Telomere dynamics in female Columbian ground squirrels: recovery after emergence and loss after reproduction. Oecologia 2022; 199:301-312. [PMID: 35713713 DOI: 10.1007/s00442-022-05194-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 05/20/2022] [Indexed: 10/18/2022]
Abstract
Telomeres are specialized non-coding DNA sequences located at the end of chromosomes and that protect genetic information. Telomere loss over lifespan is generally viewed as a phenomenon associated with aging in animals. Recently, telomere elongation after hibernation has been described in several mammals. Whether this pattern is an adaptation to repair DNA damage caused during rewarming from torpor or if it coevolved as a mechanism to promote somatic maintenance in preparation for the upcoming reproductive effort remains unclear. In a longitudinal study measuring telomere length using buccal swabs, we tested if telomere elongation was related to reproductive success in wild adult female Columbian ground squirrels (Urocitellus columbianus) that were monitored from emergence from hibernation to the end of the reproductive season. We found three key results. First, female telomere length increased at the start of the breeding season, both in breeding and non-breeding individuals. Second, post-emergence telomere lengthening was unrelated to female future reproductive output. Third, telomere length decreased in breeding females during lactation, but remained stable in non-breeding females over a similar period. Within breeders, telomeres shortened more in females producing larger and heavier litters. We concluded that telomere lengthening after hibernation did not constrain immediate female reproductive capacities. It was more likely to be part of the body recovery process that takes place after hibernation. Telomere erosion that occurs after birth may constitute a physiological cost of female reproduction.
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Affiliation(s)
- Vincent A Viblanc
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - François Criscuolo
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France.
| | - Sebastian Sosa
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - Quentin Schull
- MARBEC, University of Montpellier, IFREMER, IRD, CNRS, Avenue Jean Monnet CS 30171, 34203, Sète, France
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto, Scarborough, ON, M1C 1A4, Canada
| | - Claire Saraux
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - Mathilde Lejeune
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - Jeffrey D Roth
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Pierre Uhlrich
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - Sandrine Zahn
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
| | - F Stephen Dobson
- Université de Strasbourg, CNRS, IPHC UMR 7178, 67000, Strasbourg, France
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
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3
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Niu Y, Chen Q, Storey KB, Teng L, Li X, Xu T, Zhang H. Physiological ecology of winter hibernation by the high-altitude frog, Nanorana parkeri. Physiol Biochem Zool 2022; 95:201-211. [DOI: 10.1086/718764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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4
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Madelaire CB, Zena LA, Dillon D, Silva DP, Hunt KE, Loren Buck C, Bícego KC, Gomes FR. Who rules over immunology? Sseasonal variation in body temperature,, steroid hormones, and immune variables in a tegu lizard. Integr Comp Biol 2021; 61:1867-1880. [PMID: 34022037 DOI: 10.1093/icb/icab093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Multiple factors can influence the immune response of ectothermic vertebrates, including body temperature, gonadal steroids, and seasonality, in ways that are thought to reflect trade-offs between energetic investment in immunity vs. reproduction. Hibernating tegu lizards (Salvator merianae) are a unique model to investigate how immunocompetence might be influenced by different factors during their annual cycle. We assessed immunological measures (plasma bacterial killing ability, total and differential leukocyte count), plasma hormone levels (testosterone in males, estradiol and progesterone in females, and corticosterone in both sexes), body temperature, and body condition from adult tegus during each stage of their annual cycle: reproduction, post-reproduction/preparation for hibernation, and hibernation. Our hypothesis that immune traits present higher values during the reproductive phase, and a sharp decrease during hibernation, was partially supported. Immune variables did not change between life history stages, except for total number of leukocytes, which was higher at the beginning of the reproductive season (September) in both males and females. Average body temperature of the week prior to sampling was positively correlated with number of eosinophils, basophils, monocytes and azurophils, corroborating other studies showing that when animals maintain a high Tb, there is an increase in immune activity. Surprisingly, no clear relationship between immune traits and gonadal steroids or corticosterone levels was observed, even when including life history stage in the model. When gonadal hormones peaked in males and females, heterophil:lymphocyte ratio (which often elevates during physiological stress) also increased. Additionally, we did not observe any trade-off between reproduction and immunity traits, sex differences in immune traits or a correlation between body condition and immune response. Our results suggest that variation in patterns of immune response and correlations with body condition and hormone secretion across the year can depend upon the specific hormone and immune trait, and that experienced Tb is an important variable determining immune response in ectotherms.
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Affiliation(s)
- Carla B Madelaire
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA.,Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil
| | - Lucas A Zena
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA.,Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil.,Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, 14884-900, Brazil
| | - Danielle Dillon
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - Diego P Silva
- Smithsonian-Mason School of Conservation & George Mason University, 1500 Remount Rd, Front Royal, VA, 22630, USA
| | - Kathleen E Hunt
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, 1899 S San Francisco St, Flagstaff, AZ, 86001, USA
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, 14884-900, Brazil
| | - Fernando R Gomes
- Department of Physiology, Institute of Biosciences, University of São Paulo, Trav. 14 da Rua do Matão, 321, São Paulo, SP, 05508-090, Brazil
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Winter is coming-Temperature affects immune defenses and susceptibility to Batrachochytrium salamandrivorans. PLoS Pathog 2021; 17:e1009234. [PMID: 33600433 PMCID: PMC7891748 DOI: 10.1371/journal.ppat.1009234] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 12/08/2020] [Indexed: 12/24/2022] Open
Abstract
Environmental temperature is a key factor driving various biological processes, including immune defenses and host-pathogen interactions. Here, we evaluated the effects of environmental temperature on the pathogenicity of the emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal), using controlled laboratory experiments, and measured components of host immune defense to identify regulating mechanisms. We found that adult and juvenile Notophthalmus viridescens died faster due to Bsal chytridiomycosis at 14°C than at 6 and 22°C. Pathogen replication rates, total available proteins on the skin, and microbiome composition likely drove these relationships. Temperature-dependent skin microbiome composition in our laboratory experiments matched seasonal trends in wild N. viridescens, adding validity to these results. We also found that hydrophobic peptide production after two months post-exposure to Bsal was reduced in infected animals compared to controls, perhaps due to peptide release earlier in infection or impaired granular gland function in diseased animals. Using our temperature-dependent susceptibility results, we performed a geographic analysis that revealed N. viridescens populations in the northeastern United States and southeastern Canada are at greatest risk for Bsal invasion, which shifted risk north compared to previous assessments. Our results indicate that environmental temperature will play a key role in the epidemiology of Bsal and provide evidence that temperature manipulations may be a viable disease management strategy. In 2010, a new skin-eating fungus, Batrachochytrium salamandrivorans (Bsal), was discovered killing salamanders in the Netherlands. Since then, the pathogen has spread to other European countries. Bsal is believed to be from Asia and is being translocated through the international trade of amphibians. To our knowledge, Bsal has not arrived to North America. As a proactive strategy for disease control, we evaluated how a range of environmental temperatures in North America could affect invasion risk of Bsal into a widely distributed salamander species, the eastern newt (Notophthalmus viridescens). Our results show that northeastern USA, southeastern Canada, and the higher elevations of the Appalachian Mountains have the greatest likelihood of Bsal invasion, when temperature-dependent susceptibility is included in risk analyses. Changes in eastern newt susceptibility to Bsal infection associated with temperature are likely an interaction between pathogen replication rate and host immune defenses, including changes in skin microbiome composition and the host’s ability to produce Bsal-killing proteins on the skin. Our study provides new insights into how latitude, elevation and season can impact the epidemiology of Bsal, and suggests that strategies that manipulate microclimate of newt habitats could be useful in managing Bsal outbreaks and that climate change will impact Bsal invasion probability.
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6
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Le Sage EH, LaBumbard BC, Reinert LK, Miller BT, Richards-Zawacki CL, Woodhams DC, Rollins-Smith LA. Preparatory immunity: Seasonality of mucosal skin defences and Batrachochytrium infections in Southern leopard frogs. J Anim Ecol 2020; 90:542-554. [PMID: 33179786 DOI: 10.1111/1365-2656.13386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/28/2020] [Indexed: 12/14/2022]
Abstract
Accurately predicting the impacts of climate change on wildlife health requires a deeper understanding of seasonal rhythms in host-pathogen interactions. The amphibian pathogen, Batrachochytrium dendrobatidis (Bd), exhibits seasonality in incidence; however, the role that biological rhythms in host defences play in defining this pattern remains largely unknown. The aim of this study was to examine whether host immune and microbiome defences against Bd correspond with infection risk and seasonal fluctuations in temperature and humidity. Over the course of a year, five populations of Southern leopard frogs (Rana [Lithobates] sphenocephala) in Tennessee, United States, were surveyed for host immunity, microbiome and pathogen dynamics. Frogs were swabbed for pathogen load and skin bacterial diversity and stimulated to release stored antimicrobial peptides (AMPs). Secretions were analysed to estimate total hydrophobic peptide concentrations, presence of known AMPs and effectiveness of Bd growth inhibition in vitro. The diversity and proportion of bacterial reads with a 99% match to sequences of isolates known to inhibit Bd growth in vitro were used as an estimate of predicted anti-Bd function of the skin microbiome. Batrachochytrium dendrobatidis dynamics followed the expected seasonal fluctuations-peaks in cooler months-which coincided with when host mucosal defences were most potent against Bd. Specifically, the concentration and expression of stored AMPs cycled synchronously with Bd dynamics. Although microbiome changes followed more linear trends over time, the proportion of bacteria that can function to inhibit Bd growth was greatest when risk of Bd infection was highest. We interpret the increase in peptide storage in the fall and the shift to a more anti-Bd microbiome over winter as a preparatory response for subsequent infection risk during the colder periods when AMP synthesis and bacterial growth is slow and pathogen pressure from this cool-adapted fungus is high. Given that a decrease in stored AMP concentrations as temperatures warm in spring likely means greater secretion rates, the subsequent decrease in prevalence suggests seasonality of Bd in this host may be in part regulated by annual immune rhythms, and dominated by the effects of temperature.
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Affiliation(s)
- Emily H Le Sage
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | - Laura K Reinert
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Brian T Miller
- Department of Biology, Middle Tennessee State University, Murfreesboro, TN, USA
| | | | - Doug C Woodhams
- Department of Biology, University of Massachusetts, Boston, MA, USA
| | - Louise A Rollins-Smith
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.,Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA
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7
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Rollins-Smith LA. Global Amphibian Declines, Disease, and the Ongoing Battle between Batrachochytrium Fungi and the Immune System. HERPETOLOGICA 2020. [DOI: 10.1655/0018-0831-76.2.178] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Louise A. Rollins-Smith
- Departments of Pathology, Microbiology and Immunology and Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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8
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Campbell L, Bower DS, Clulow S, Stockwell M, Clulow J, Mahony M. Interaction between temperature and sublethal infection with the amphibian chytrid fungus impacts a susceptible frog species. Sci Rep 2019; 9:83. [PMID: 30643160 PMCID: PMC6331562 DOI: 10.1038/s41598-018-35874-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 11/07/2018] [Indexed: 11/09/2022] Open
Abstract
The amphibian chytrid fungus Batrachochytrium dendrobatidis is an emerging infectious pathogen present on every continent except Antarctica. It causes the disease chytridiomycosis in a subset of species but does not always result in disease or death for every host. Ambient temperature influences both amphibian metabolism and chytrid pathogenicity, however the interactive effects on host physiology is not well understood. We investigated the sublethal effect of B. dendrobatidis infection on a susceptible host, Litoria aurea to test (1) whether the infection load, metabolic activity, body fat and gonad size differed in L. aurea at either 24 °C or 12 °C ambient temperatures and (2) whether previous Bd infection caused long-term changes to body fat and gonad size. Litoria aurea in 12 °C treatments had higher infection loads of B. dendrobatidis and lower survivorship. Metabolic rate was higher and fat mass was lower in infected individuals and in animals in 24 °C treatments. Male L. aurea previously infected with B. dendrobatidis had smaller testes 5 months-post clearance of infection, an effect likely to translate to fitness costs in wild populations. These experiments demonstrate a physiological cost to sublethal B. dendrobatidis infection, which suggests a reduction in host fitness mediated by temperature in the host's environment regardless of whether infection leads to mortality.
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Affiliation(s)
- Lachlan Campbell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia.
| | - Deborah S Bower
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia.,James Cook University, Townsville, 4811, Qld, Australia
| | - Simon Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia.,Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Michelle Stockwell
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia
| | - John Clulow
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia
| | - Michael Mahony
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, Newcastle, 2300, NSW, Australia
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9
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Bower DS, Brannelly LA, McDonald CA, Webb RJ, Greenspan SE, Vickers M, Gardner MG, Greenlees MJ. A review of the role of parasites in the ecology of reptiles and amphibians. AUSTRAL ECOL 2018. [DOI: 10.1111/aec.12695] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Deborah S. Bower
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
- School of Environmental and Rural Science; University of New England; Armidale New South Wales Australia
| | - Laura A. Brannelly
- Department of Biological Sciences; University of Pittsburgh; Pittsburgh Pennsylvania USA
| | - Cait A. McDonald
- Department of Ecology and Evolutionary Biology; Cornell University; Ithaca New York USA
| | - Rebecca J. Webb
- College of Public Health, Medical and Veterinary Sciences; James Cook University; Townsville Queensland Australia
| | - Sasha E. Greenspan
- Department of Biological Sciences; University of Alabama; Tuscaloosa Alabama USA
| | - Mathew Vickers
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
| | - Michael G. Gardner
- College of Science and Engineering; Flinders University; Adelaide South Australia Australia
- Evolutionary Biology Unit; South Australian Museum; Adelaide South Australia Australia
| | - Matthew J. Greenlees
- School of Life and Environmental Sciences; University of Sydney; Sydney New South Wales Australia
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10
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Greenspan SE, Bower DS, Webb RJ, Berger L, Rudd D, Schwarzkopf L, Alford RA. White blood cell profiles in amphibians help to explain disease susceptibility following temperature shifts. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 77:280-286. [PMID: 28870450 DOI: 10.1016/j.dci.2017.08.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
Temperature variability, and in particular temperature decreases, can increase susceptibility of amphibians to infections by the fungus Batrachochytrium dendrobatidis (Bd). However, the effects of temperature shifts on the immune systems of Bd-infected amphibians are unresolved. We acclimated frogs to 16 °C and 26 °C (baseline), simultaneously transferred them to an intermediate temperature (21 °C) and inoculated them with Bd (treatment), and tracked their infection levels and white blood cell profiles over six weeks. Average weekly infection loads were consistently higher in 26°C-history frogs, a group that experienced a 5 °C temperature decrease, than in 16°C-history frogs, a group that experienced a 5 °C temperature increase, but this pattern only approached statistical significance. The 16°C-acclimated frogs had high neutrophil:lymphocyte (N:L) ratios (suggestive of a hematopoietic stress response) at baseline, which were conserved post-treatment. In contrast, the 26°C-acclimated frogs had low N:L ratios at baseline which reversed to high N:L ratios post-treatment (suggestive of immune system activation). Our results suggest that infections were less physiologically taxing for the 16°C-history frogs than the 26°C-history frogs because they had already adjusted immune parameters in response to challenging conditions (cold). Our findings provide a possible mechanistic explanation for observations that amphibians are more susceptible to Bd infection following temperature decreases compared to increases and underscore the consensus that increased temperature variability associated with climate change may increase the impact of infectious diseases.
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Affiliation(s)
- Sasha E Greenspan
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia.
| | - Deborah S Bower
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Donna Rudd
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lin Schwarzkopf
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Ross A Alford
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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11
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Udroiu I, Sgura A. The Phylogeny of the Spleen. THE QUARTERLY REVIEW OF BIOLOGY 2017. [DOI: 10.1086/695327] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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12
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Madelaire CB, Sokolova I, Gomes FR. Seasonal Patterns of Variation in Steroid Plasma Levels and Immune Parameters in Anurans from Brazilian Semiarid Area. Physiol Biochem Zool 2017; 90:415-433. [PMID: 28398155 DOI: 10.1086/691202] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Elevated androgens and glucocorticoids displayed by males during the reproductive season have been proposed to mediate a possible trade-off between reproduction and immunocompetence. Anurans living in arid and semiarid environments display a strong seasonal reproduction, which could accentuate the variation in physiological, immunological, and behavioral parameters. We studied covariation between steroid plasma levels, morphometric variables associated with body condition and immunity, leukocyte profile, parasite load, and response to an immunological challenge across different phases of the annual life-history cycle of three anuran species from a Brazilian semiarid area. Our results showed a seasonal pattern of covariation among leukocyte parameters, kidney mass, and steroid plasma levels, with higher values measured during the reproductive season, particularly when males were sampled during calling activity. Moreover, these anurans showed a stronger response to an immunological challenge during the reproductive period. The immunosuppression during the dry period was particularly evident for the species that aestivate, indicating that the availability of energetic resources might be an important factor determining seasonal variation in inflammatory response. Intensity of the helminth infection was associated with eosinophil count but showed a more complex pattern with regard to androgens levels. These data emphasize that variations in the intensity of helminth infection might be more closely related to specific aspects of the immune response than to the general seasonal patterns of variation in steroid plasma levels, total circulating leukocytes, and inflammatory response.
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13
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Origgi FC, Schmidt BR, Lohmann P, Otten P, Akdesir E, Gaschen V, Aguilar-Bultet L, Wahli T, Sattler U, Stoffel MH. Ranid Herpesvirus 3 and Proliferative Dermatitis in Free-Ranging Wild Common Frogs (Rana Temporaria). Vet Pathol 2017; 54:686-694. [PMID: 28494706 DOI: 10.1177/0300985817705176] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Amphibian pathogens are of current interest as contributors to the global decline of amphibians. However, compared with chytrid fungi and ranaviruses, herpesviruses have received relatively little attention. Two ranid herpesviruses have been described: namely, Ranid herpesvirus 1 (RHV1) and Ranid herpesvirus 2 (RHV2). This article describes the discovery and partial characterization of a novel virus tentatively named Ranid herpesvirus 3 (RHV3), a candidate member of the genus Batrachovirus in the family Alloherpesviridae. RHV3 infection in wild common frogs (Rana temporaria) was associated with severe multifocal epidermal hyperplasia, dermal edema, a minor inflammatory response, and variable mucous gland degeneration. Intranuclear inclusions were numerous in the affected epidermis together with unique extracellular aggregates of herpesvirus-like particles. The RHV3-associated skin disease has features similar to those of a condition recognized in European frogs for the last 20 years and whose cause has remained elusive. The genome of RHV3 shares most of the features of the Alloherpesviruses. The characterization of this presumptive pathogen may be of value for amphibian conservation and for a better understanding of the biology of Alloherpesviruses.
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Affiliation(s)
- F C Origgi
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland.,2 Institute of Veterinary Bacteriology, DIP, Bern, Switzerland
| | - B R Schmidt
- 3 KARCH, Neuchâtel, Switzerland, and Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | | | - P Otten
- 5 Fasteris SA, Geneva, Switzerland
| | - E Akdesir
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland
| | - V Gaschen
- 6 Division of Veterinary Anatomy, University of Bern, Bern, Switzerland
| | | | - T Wahli
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland
| | - U Sattler
- 1 Department of Infectious Diseases and Pathobiology (DIP), Centre for Fish and Wildlife Health (FIWI), University of Bern, Bern, Switzerland
| | - M H Stoffel
- 6 Division of Veterinary Anatomy, University of Bern, Bern, Switzerland
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14
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Lillywhite HB, Shine R, Jacobson E, DeNardo DF, Gordon MS, Navas CA, Wang T, Seymour RS, Storey KB, Heatwole H, Heard D, Brattstrom B, Burghardt GM. Anesthesia and Euthanasia of Amphibians and Reptiles Used in Scientific Research: Should Hypothermia and Freezing Be Prohibited? Bioscience 2016. [DOI: 10.1093/biosci/biw143] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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15
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Hibernal Habitat Selection by Wood Frogs (Lithobates sylvaticus) in a Northern New England Montane Landscape. J HERPETOL 2016. [DOI: 10.1670/15-131r1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Forbes MR, Mcruer DL, Rutherford PL. Prevalence of Aeromonas hydrophila in relation to timing and duration of breeding in three species of ranid frogs. ECOSCIENCE 2016. [DOI: 10.1080/11956860.2004.11682834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Mark R. Forbes
- Department of Biology, 209 Nesbitt Building, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario KlS 5B6, Canada
| | - David L. Mcruer
- Department of Biology, 209 Nesbitt Building, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario KlS 5B6, Canada
| | - Pamela L. Rutherford
- Department of Biology, 209 Nesbitt Building, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario KlS 5B6, Canada
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Sieckmann DG, Jaffe H, Golech S, Cai D, Hallenbeck JM, McCarron RM. Anti-lymphoproliferative activity of alpha-2-macroglobulin in the plasma of hibernating 13-lined ground squirrels and woodchucks. Vet Immunol Immunopathol 2014; 161:1-11. [PMID: 25113962 DOI: 10.1016/j.vetimm.2014.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 03/14/2014] [Accepted: 05/10/2014] [Indexed: 11/19/2022]
Abstract
Plasma from hibernating (HIB) woodchucks (Marmota monax) or 13-lined ground squirrels (Ictidomys tridecemlineatus) suppressed (3)H-thymidine uptake in mouse spleen cell cultures stimulated with Concanavalin A (ConA); plasma from non-hibernating animals were only slightly inhibitory. Maximum inhibition occurred when HIB plasma was added to the cultures prior to ConA. After HPLC size exclusion chromatography of the HIB ground squirrel plasma, a single fraction (fraction-14) demonstrated inhibitory activity. Assay of fraction-14 from 8 HIB squirrels showed inhibition ranging from 13 to 95%; inhibition was correlated to the time the squirrels were exposed to cold prior to hibernation. Western blot analysis showed the factor to be a large molecular weight protein (>300 kDa), and mass spectrometry identified sequences that were 100% homologous with alpha-2-macroglobulin from humans and other species. These findings indicate a hibernation-related protein that may be responsible for immune system down regulation.
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Affiliation(s)
- Donna G Sieckmann
- Naval Medical Research Center, Silver Spring, MD 20910, United States.
| | - Howard Jaffe
- LNC-NINDS Protein/Peptide Sequencing Facility, NINDS, NIH, Bethesda, MD 20892, United States
| | - Susanne Golech
- Naval Medical Research Center, Silver Spring, MD 20910, United States
| | - DeCheng Cai
- Stroke Branch, NINDS, NIH, Bethesda, MD 20892, United States
| | | | - Richard M McCarron
- Naval Medical Research Center, Silver Spring, MD 20910, United States; Department of Pathology, USUHS, Bethesda, MD 20814, United States.
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Sahdo B, Evans AL, Arnemo JM, Fröbert O, Särndahl E, Blanc S. Body temperature during hibernation is highly correlated with a decrease in circulating innate immune cells in the brown bear (Ursus arctos): a common feature among hibernators? Int J Med Sci 2013; 10:508-14. [PMID: 23532623 PMCID: PMC3607235 DOI: 10.7150/ijms.4476] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 02/10/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Hibernation involves periods of severely depressed metabolism (torpor) and decreases in body temperature (Tb). Small arctic mammals (<5kg), in which Tb generally drop drastically, display leukopenia during hibernation. This raised the question of whether the decreased leukocyte counts in mammalian hibernators is due to torpor per se or is secondary to low Tb. The present study examined immune cell counts in brown bears (Ursus arctos), where torpor is only associated with shallow decreases in Tb. The results were compared across hibernator species for which immune and Tb data were available. METHODS AND RESULTS The white blood cell counts were determined by flow cytometry in 13 bears captured in the field both during summer and winter over 2 years time. Tb dropped from 39.6±0.8 to 33.5±1.1°C during hibernation. Blood neutrophils and monocytes were lower during hibernation than during the active period (47%, p= 0.001; 43%, p=0.039, respectively), whereas no change in lymphocyte counts was detected (p=0.599). Further, combining our data and those from 10 studies on 9 hibernating species suggested that the decline in Tb explained the decrease in innate immune cells (R(2)=0.83, p<0.0001). CONCLUSIONS Bears have fewer innate immune cells in circulation during hibernation, which may represent a suppressed innate immune system. Across species comparison suggests that, both in small and large hibernators, Tb is the main driver of immune function regulation during winter dormancy. The lack of a difference in lymphocyte counts in this context requires further investigations.
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Affiliation(s)
- Berolla Sahdo
- 1. Department of Clinical Medicine, School of Health and Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
| | - Alina L. Evans
- 2. Department of Forestry and Wildlife Management, Hedmark University College, Campus Evenstad NO-2418 Elverum, Norway
- 3. Section of Arctic Veterinary Medicine, Norwegian School of Veterinary Science, NO-9292 Tromsø, Norway
| | - Jon M. Arnemo
- 2. Department of Forestry and Wildlife Management, Hedmark University College, Campus Evenstad NO-2418 Elverum, Norway
- 4. Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Ole Fröbert
- 5. Department of Cardiology, Örebro University Hospital, SE-701 85 Örebro, Sweden
| | - Eva Särndahl
- 1. Department of Clinical Medicine, School of Health and Medical Sciences, Örebro University, SE-701 82 Örebro, Sweden
- 5. Department of Cardiology, Örebro University Hospital, SE-701 85 Örebro, Sweden
| | - Stéphane Blanc
- 6. Université de Strasbourg, IPHC, 23 rue Becquerel 67087 Strasbourg, France, CNRS, UMR7178, 67037 Strasbourg, France
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Christin MS, Ménard L, Giroux I, Marcogliese DJ, Ruby S, Cyr D, Fournier M, Brousseau P. Effects of agricultural pesticides on the health of Rana pipiens frogs sampled from the field. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:601-611. [PMID: 22992987 DOI: 10.1007/s11356-012-1160-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 08/27/2012] [Indexed: 06/01/2023]
Abstract
There is evidence that over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations due to disease outbreaks. Multiple causes have been suggested to explain this increase in disease incidence. Among these, climate changes, environmental pollution and reduced water quality are gaining attention. Indeed, some chemicals of environmental concerns are known to alter the immune system. It is possible that exposure to these pollutants could alter the immune system of anurans and render them more susceptible to different pathogens. In this study, we sampled Rana pipiens in five different sites near St. Lawrence River (Quebec, Canada) during the months of July and September in 2001. Two of these sites were protected areas, in which low levels of pesticides were detected, while the remaining three sites were located in areas with intensive corn and soybeans cultivations. Our results demonstrated that frogs living in agricultural regions are smaller in size and weight than frogs living in areas with lower levels of pesticides at both sampling times. Moreover, we have observed a significant decrease in the number of splenocytes (cellularity) and the phagocytic activity in frogs sampled in impacted sites. Taken together, these results suggest that frogs living in agricultural regions might be more vulnerable to infections and diseases through their smaller size and alteration of their immune system. Our results also contribute to the overall discussion on factors involved in amphibian declines.
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Affiliation(s)
- M S Christin
- INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, QC, Canada H7V 1B7
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21
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Flechas SV, Sarmiento C, Cárdenas ME, Medina EM, Restrepo S, Amézquita A. Surviving chytridiomycosis: differential anti-Batrachochytrium dendrobatidis activity in bacterial isolates from three lowland species of Atelopus. PLoS One 2012; 7:e44832. [PMID: 22970314 PMCID: PMC3438167 DOI: 10.1371/journal.pone.0044832] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 08/08/2012] [Indexed: 11/19/2022] Open
Abstract
In the Neotropics, almost every species of the stream-dwelling harlequin toads (genus Atelopus) have experienced catastrophic declines. The persistence of lowland species of Atelopus could be explained by the lower growth rate of Batrachochytrium dendrobatidis (Bd) at temperatures above 25 °C. We tested the complementary hypothesis that the toads' skin bacterial microbiota acts as a protective barrier against the pathogen, perhaps delaying or impeding the symptomatic phase of chytridiomycosis. We isolated 148 cultivable bacterial strains from three lowland Atelopus species and quantified the anti-Bd activity through antagonism assays. Twenty-six percent (38 strains representing 12 species) of the bacteria inhibited Bd growth and just two of them were shared among the toad species sampled in different localities. Interestingly, the strongest anti-Bd activity was measured in bacteria isolated from A. elegans, the only species that tested positive for the pathogen. The cutaneous bacterial microbiota is thus likely a fitness-enhancing trait that may (adaptation) or not (exaptation) have appeared because of natural selection mediated by chytridiomycosis. Our findings reveal bacterial strains for development of local probiotic treatments against chytridiomycosis and also shed light on the mechanisms behind the frog-bacteria-pathogen interaction.
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Affiliation(s)
- Sandra V. Flechas
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Carolina Sarmiento
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Martha E. Cárdenas
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Edgar M. Medina
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Silvia Restrepo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Adolfo Amézquita
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
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Rollins-Smith LA, Ramsey JP, Pask JD, Reinert LK, Woodhams DC. Amphibian immune defenses against chytridiomycosis: impacts of changing environments. Integr Comp Biol 2011; 51:552-62. [PMID: 21816807 DOI: 10.1093/icb/icr095] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Eco-immunology is the field of study that attempts to understand the functions of the immune system in the context of the host's environment. Amphibians are currently suffering devastating declines and extinctions in nearly all parts of the world due to the emerging infectious disease chytridiomycosis caused by the chytrid fungus, Batrachochytrium dendrobatidis. Because chytridiomycosis is a skin infection and remains confined to the skin, immune defenses of the skin are critical for survival. Skin defenses include secreted antimicrobial peptides and immunoglobulins as well as antifungal metabolites produced by symbiotic skin bacteria. Low temperatures, toxic chemicals, and stress inhibit the immune system and may impair natural defenses against B. dendrobatidis. Tadpoles' mouth parts can be infected by B. dendrobatidis. Damage to the mouth parts can impair growth, and the affected tadpoles maintain the pathogen in the environment even when adults have dispersed. Newly metamorphosing frogs appear to be especially vulnerable to infection and to the lethal effects of this pathogen because the immune system undergoes a dramatic reorganization at metamorphosis, and postmetamorphic defenses are not yet mature. Here we review our current understanding of amphibian immune defenses against B. dendrobatidis and the ability of the pathogen to resist those defenses. We also briefly review what is known about the impacts of temperature, environmental chemicals, and stress on the host-pathogen interactions and suggest future directions for research.
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Affiliation(s)
- Louise A Rollins-Smith
- Department of Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Direct and Indirect Effects of Climate Change on Amphibian Populations. DIVERSITY-BASEL 2010. [DOI: 10.3390/d2020281] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ribas L, Li MS, Doddington BJ, Robert J, Seidel JA, Kroll JS, Zimmerman LB, Grassly NC, Garner TWJ, Fisher MC. Expression profiling the temperature-dependent amphibian response to infection by Batrachochytrium dendrobatidis. PLoS One 2009; 4:e8408. [PMID: 20027316 PMCID: PMC2794374 DOI: 10.1371/journal.pone.0008408] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 11/20/2009] [Indexed: 01/31/2023] Open
Abstract
Amphibians are experiencing a panzootic of unprecedented proportions caused by the emergence of Batrachochytrium dendrobatidis (Bd). However, all species are not equally at risk of infection, and risk is further modified by environmental variables, specifically temperature. In order to understand how, and when, hosts mount a response to Bd we analysed infection dynamics and patterns of gene expression in the model amphibian species Silurana (Xenopus) tropicalis. Mathematical modelling of infection dynamics demonstrate the existence of a temperature-dependent protective response that is largely independent of the intrinsic growth-rate of Bd. Using temporal expression-profiling by microarrays and qRT-PCR, we characterise this response in the main amphibian lymphoid tissue, the spleen. We demonstrate that clearance of Bd at the host-optimal temperature is not clearly associated with an adaptive immune response, but rather is correlated with the induction of components of host innate immunity including the expression of genes that are associated with the production of the antimicrobial skin peptide preprocareulein (PPCP) as well as inflammatory responses. We find that adaptive immunity appears to be lacking at host-optimal temperatures. This suggests that either Bd does not stimulate, or suppresses, adaptive immunity, or that trade-offs exist between innate and adaptive limbs of the amphibian immune system. At cold temperatures, S. tropicalis loses the ability to mount a PPCP-based innate response, and instead manifests a more pronounced inflammatory reaction that is characterised by the production of proteases and higher pathogen burdens. This study demonstrates the temperature-dependency of the amphibian response to infection by Bd and indicates the influence that changing climates may exert on the ectothermic host response to pathogens.
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Affiliation(s)
- Laia Ribas
- Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | - Ming-Shi Li
- Department of Paediatrics, Imperial College London, London, United Kingdom
| | | | - Jacques Robert
- University of Rochester Medical Centre, Rochester, New York, United States of America
| | - Judith A. Seidel
- Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | - J. Simon Kroll
- Department of Paediatrics, Imperial College London, London, United Kingdom
| | - Lyle B. Zimmerman
- Developmental Biology, National Institute for Medical Research, London, United Kingdom
| | - Nicholas C. Grassly
- Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | | | - Matthew C. Fisher
- Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
- * E-mail:
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25
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Dare OK, Forbes MR. Patterns of infection by lungworms, Rhabdias ranae and Haematoloechus spp., in northern leopard frogs: a relationship between sex and parasitism. J Parasitol 2009; 95:275-80. [PMID: 18712948 DOI: 10.1645/ge-1713.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Accepted: 08/14/2008] [Indexed: 11/10/2022] Open
Abstract
We examined a population of northern leopard frogs to determine whether sex biases in investment in immunity, previously reported for this host species under controlled exposures to lung nematodes, is predictive of patterns of parasitism in nature. We examined Rhabdias ranae and Haematoloechus spp. infections in 74 breeding adult, 28 non-breeding adult, and 53 juvenile frogs. Contrary to our predictions, R. ranae prevalence and mean abundance were higher in breeding female frogs (prevalence: 39.4%, abundance: 3.05 +/- 0.85) than on breeding males (prevalence: 26.0%, abundance: 1.17 +/- 0.52), although no sex bias was observed among non-breeding adults or juvenile frogs. Female frogs also carried larger R. ranae worms, on average, than did males (females: 6407.38 microm +/- 153.80; males: 5198 microm +/- 131.09), regardless of age or breeding condition. We observed no sex-linked patterns of parasitism by Haematoloechus spp. worms in either adult or juvenile frogs. Alternative hypotheses, such as differences among sexes in the selection of thermal clines for hibernation, may explain the observed female bias in parasitism by nematode lungworms in nature and, thus, need to be considered.
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Affiliation(s)
- Oluwayemisi K Dare
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada.
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26
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Woodhams DC, Alford RA, Briggs CJ, Johnson M, Rollins-Smith LA. Life-history trade-offs influence disease in changing climates: strategies of an amphibian pathogen. Ecology 2008; 89:1627-39. [PMID: 18589527 DOI: 10.1890/06-1842.1] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Life-history trade-offs allow many animals to maintain reproductive fitness across a range of climatic conditions. When used by parasites and pathogens, these strategies may influence patterns of disease in changing climates. The chytrid fungus, Batrachochytrium dendrobatidis, is linked to global declines of amphibian populations. Short-term growth in culture is maximal at 17 degrees-25 degrees C. This has been used in an argument that global warming, which increases the time that amphibians spend at these temperatures in cloud-covered montane environments, has led to extinctions. Here we show that the amphibian chytrid responds to decreasing temperatures with trade-offs that increase fecundity as maturation rate slows and increase infectivity as growth decreases. At 17 degrees-25 degrees C, infectious zoospores encyst (settle and develop a cell wall) and develop into the zoospore-producing stage (zoosporangium) faster, while at 7 degrees-10 degrees C, greater numbers of zoospores are produced per zoosporangium; these remain infectious for a longer period of time. We modeled the population growth of B. dendrobatidis through time at various temperatures using delayed differential equations and observational data for four parameters: developmental rate of thalli, fecundity, rate of zoospore encystment, and rate of zoospore survival. From the models, it is clear that life-history trade-offs allow B. dendrobatidis to maintain a relatively high long-term growth rate at low temperatures, so that it maintains high fitness across a range of temperatures. When a seven-day cold shock is simulated, the outcome is intermediate between the two constant temperature regimes, and in culture, a sudden drop in temperature induces zoospore release. These trade-offs can be ecologically important for a variety of organisms with complex life histories, including pathogenic microorganisms. The effect of temperature on amphibian mortality will depend on the interaction between fungal growth and host immune function and will be modified by host ecology, behavior, and life history. These results demonstrate that B. dendrobatidis populations can grow at high rates across a broad range of environmental temperatures and help to explain why it is so successful in cold montane environments.
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Affiliation(s)
- Douglas C Woodhams
- Department of Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee 37232, USA.
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Gupta V, Singh SM, Singh MP, Singh G. Effect of Intrauterine Exposure of Murine Fetus to Cyclophosphamide on Development of Thymus. Immunopharmacol Immunotoxicol 2008; 29:17-30. [PMID: 17464764 DOI: 10.1080/08923970701277635] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The objective of this study was to demonstrate thymic alterations produced by cyclophosphamide intervention during intrauterine life of murine fetus. Cyclophosphamide (CP) was administered to pregnant mice on day 11 of gestation in a single dose of 10 mg/kg body weight. Fetuses were dissected out on day 19 and studied for various effects on thymus. Thymus of fetuses exposed to cyclophosphamide showed thymic atrophy with retardation of thymic size and a remarkable shrinkage in lobular morphology. Histological studies showed a massive depletion of thymic cortex. Study of thymocytes revealed an increase in apoptotic cell count and percent DNA fragmentation along with a decrease in proliferation. Thymocytes obtained from fetuses of CP-treated mice showed a higher expression of caspase-activated DNase (CAD) indicating that the CP-dependent induction of apoptosis in thymocytes involved caspase pathway. The results of the present study may help in understanding the mechanism of the teratogenic effect of cyclophosphamide on thymus.
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Woodhams DC, Ardipradja K, Alford RA, Marantelli G, Reinert LK, Rollins-Smith LA. Resistance to chytridiomycosis varies among amphibian species and is correlated with skin peptide defenses. Anim Conserv 2007. [DOI: 10.1111/j.1469-1795.2007.00130.x] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Solís ME, Bandeff JM, Huang Y. HEMATOLOGY AND SERUM CHEMISTRY OF OZARK AND EASTERN HELLBENDERS (CRYPTOBRANCHUS ALLEGANIENSIS). HERPETOLOGICA 2007. [DOI: 10.1655/0018-0831(2007)63[285:hascoo]2.0.co;2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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RAFFEL TR, ROHR JR, KIESECKER JM, HUDSON PJ. Negative effects of changing temperature on amphibian immunity under field conditions. Funct Ecol 2006. [DOI: 10.1111/j.1365-2435.2006.01159.x] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Forbes MR, McRuer DL, Shutler D. White blood cell profiles of breeding American toads (Bufo americanus) relative to sex and body size. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/s00580-006-0623-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Rollins-Smith LA, Woodhams DC, Reinert LK, Vredenburg VT, Briggs CJ, Nielsen PF, Conlon JM. Antimicrobial peptide defenses of the mountain yellow-legged frog (Rana muscosa). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2006; 30:831-42. [PMID: 16330099 DOI: 10.1016/j.dci.2005.10.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Accepted: 10/07/2005] [Indexed: 05/05/2023]
Abstract
The mountain yellow-legged frog (Rana muscosa) inhabits high elevation lakes in California that are largely undisturbed by human activities. In spite of this habitation in remote sites, populations continue to decline. Although predation by non-native fish is one cause for declines, some isolated populations in fishless lakes are suffering new declines. One possible cause of the current wave of declines is the introduction of the pathogenic chytrid fungus (Batrachochytrium dendrobatidis) which invades the adult skin to cause chytridiomycosis. In many amphibian species, the skin is protected by antimicrobial peptides secreted into the mucous. Here we show that R. muscosa produces three previously unknown antimicrobial peptides belonging to the ranatuerin-2 and temporin-1 families of antimicrobial peptides. These three peptides, along with bradykinin, are the most abundant peptides in the skin secretions detected by mass spectrometry. Natural mixtures of peptides and individual purified peptides strongly inhibit chytrid growth. The concentration of total peptides recovered from the skin of frogs following a mild norepinephrine induction is sufficient to inhibit chytrid growth in vitro. A comparison of the species susceptibility to chytridiomycosis and the antichytrid activity of peptides between R. muscosa and R. pipiens suggest that although R. muscosa produces more total skin peptides, it appears to be more vulnerable to B. dendrobatidis in nature. Possible differences in the antimicrobial peptide repertoires and life history traits of the two species that may account for differences in susceptibility are discussed.
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Affiliation(s)
- Louise A Rollins-Smith
- Department of Microbiology and Immunology, Vanderbilt University, A-5301 Medical Center North, Nashville, TN 37232, USA.
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Abstract
Amphibians are a diverse group of species; much work remains to be done to elucidate the viruses of amphibians. Viral diseases may play an important role in wild and captive amphibian populations. Iridoviruses are a leading cause of wild amphibian mortality events in the United States and are a common cause of amphibian mortality events worldwide. In addition to frank viral diseases, viral infections may play a role in the establishment of bacterial, fungal, and parasitic diseases and are an underlying cause of neoplasia. It is important for the amphibian clinician to recognize disease syndromes and pathology that are consistent with viral etiology.
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Affiliation(s)
- April J Johnson
- College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
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34
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Shanker A. Is thymus redundant after adulthood? Immunol Lett 2004; 91:79-86. [PMID: 15019273 DOI: 10.1016/j.imlet.2003.12.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2003] [Revised: 12/20/2003] [Accepted: 12/28/2003] [Indexed: 11/29/2022]
Abstract
Thymus is considered to involute with age with a decline in thymic function. However, this generality is not universally and incontrovertibly true. Many studies performed in animals and men have proved to the contrary that thymic activity and function appear to be well maintained in the old age and may be indispensable for T cell reconstitution in different immunological settings. During some clinical situations where T cell pool needs to be regenerated, renewal of thymic activity and mass has been observed in an otherwise dormant thymic remnant. New studies have revealed a dynamic interplay between postnatal thymus output and peripheral T cell pool. Moreover, age-related loss of thymic function appears to be only quantitative and not qualitative. This review, thus, focuses on the different conditions that lead to thymic involution and attempts to bring about the emerging notion and the clinical relevance of continuous thymic activity well beyond the adulthood to optimise the function of the immune system in the context of cancer and infectious diseases.
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Affiliation(s)
- Anil Shanker
- Centre d'Immunologie de Marseille-Luminy, Institut National de la Santé et de la Recherche Médicale, Université de la Méditerranée, 163 Avenue de Luminy, Case 906, Marseille Cedex 09, 13288 France.
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Christin MS, Ménard L, Gendron AD, Ruby S, Cyr D, Marcogliese DJ, Rollins-Smith L, Fournier M. Effects of agricultural pesticides on the immune system of Xenopus laevis and Rana pipiens. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2004; 67:33-43. [PMID: 15019249 DOI: 10.1016/j.aquatox.2003.11.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Revised: 11/07/2003] [Accepted: 11/18/2003] [Indexed: 05/21/2023]
Abstract
Over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations. Multiple causes have been suggested to explain this decline. Among these, environmental pollution is gaining attention. Indeed, some chemicals of environmental concern are known to alter the immune system. Given that amphibians are frequently exposed to agricultural pesticides, it is possible that these pollutants alter their immune system and render them more susceptible to different pathogens. In this study, we exposed two frog species, Xenopus laevis and Rana pipiens, for a short period of time to a mixture of pesticides (atrazine, metribuzine, endosulfan, lindane, aldicarb and dieldrin) representative in terms of composition and concentrations to what it is found in the environment of the southwest region of the province of Quebec. The pesticides were known to be present in surface water of many tributaries of the St. Lawrence River (Quebec, Canada). Our results demonstrate that the mixture of pesticides could alter the cellularity and phagocytic activity of X. laevis and the lymphocyte proliferation of R. pipiens. Taken together, these results indicate that agricultural pesticides can alter some aspects of the immune response in frogs and could contribute to their global decline by rendering them more susceptible to certain infections.
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Affiliation(s)
- M S Christin
- INRS-Institut Armand-Frappier/Santé Humaine, 245 Hymus Blvd., Pointe-Claire, Que., Canada H9R 1G6
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Domínguez-Gerpe L, Rey-Méndez M. Evolution of the thymus size in response to physiological and random events throughout life. Microsc Res Tech 2003; 62:464-76. [PMID: 14635139 DOI: 10.1002/jemt.10408] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During embryogenesis and in the early stages of life, the thymus is a crucial organ for the generation of the T cell repertoire. T cells are generated from hematopoietic stem cells already differentiated to precursor T cells in the bone marrow. These cells enter the thymus guided by chemotactic factors secreted by this organ. The complex maturation process takes place that ensures self-tolerance and homeostasis. Thymocytes that show autoreactivity do not leave the thymus, but rather die by apoptosis. The final percentage of mature T cells that survive to migrate from the thymus to the periphery is very low: at most 5%, under optimal conditions. The highest migration occurs in childhood and adulthood, at least in mice and humans; however, it declines throughout life and is minimal in the elderly. Under normal circumstances, the thymus commences involution soon after birth, and this involution correlates with the capacity to export mature T cells to the periphery. Hormones, cytokines, and neurotransmitters all play a role in this age-associated process, but the reasons for and mechanisms of this involution remain unknown. Apart from physiological conditions that change throughout life and govern age-related thymus evolution, random states and events provoked by intrinsic or extrinsic factors can induce either thymus involution, as in reversible transient thymic hypoplasias, or thymic hyperplasias. The age-associated involution, unlike transient involutions, follows a regular pattern for all individuals, though there are clear differences between the sexes. Nevertheless, even the age-associated involution seems to be reversible, raising the possibility of therapeutic strategies aimed at enhancing thymus function in the elderly.
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Affiliation(s)
- Lourdes Domínguez-Gerpe
- Departamento de Bioquímica y Biología Molecular, Facultad de Biología, Universidad de Santiago de Compostela, 15706 Santiago de Compostela, La Coruña, Spain.
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Brodkin M, Vatnick I, Simon M, Hopey H, Butler-Holston K, Leonard M. Effects of acid stress in adult Rana pipiens. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, COMPARATIVE EXPERIMENTAL BIOLOGY 2003; 298:16-22. [PMID: 12840835 DOI: 10.1002/jez.a.10270] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The decline in frog populations is a well-recognized worldwide phenomenon and infectious disease has been implicated as a major cause in the global decline of amphibian populations. Rana pipiens are disappearing from many habitats where they used to flourish, and environmental acidification has been considered as a possible contributor to this disappearance. We present a model that integrates the results of several experiments on the effects of acid exposure on natural resistance and mortality of adult Rana pipiens. These studies suggest that different components of the natural defense mechanisms of these frogs have different acid sensitivities. We have shown previously that exposure to pH 5.5 leads to a reduction in splenic white blood cell number, viability, and to colonization of the spleen with both Gram positive and Gram negative bacteria. In this paper we show that exposure to pH 6.0 did not affect the number or viability of splenic white blood cells but did result in colonization of the spleen by bacteria. We also show that cold exposure by itself does not cause a systemic bacterial infection in adult Rana pipiens, but acid stress following cold exposure does. The data presented in this paper provide empirical evidence to support the hypothesis that acid stress may be a contributor to the decline of Rana pipiens in the northeastern region of the United States.
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Affiliation(s)
- Marc Brodkin
- Department of Biology, Science Division, Widener University, Chester, Pennsylvania 19013, USA.
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Palenske NM, Saunders DK. Blood viscosity and hematology of American bullfrogs (Rana catesbeiana) at low temperature. J Therm Biol 2003. [DOI: 10.1016/s0306-4565(03)00002-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Christin MS, Gendron AD, Brousseau P, Ménard L, Marcogliese DJ, Cyr D, Ruby S, Fournier M. Effects of agricultural pesticides on the immune system of Rana pipiens and on its resistance to parasitic infection. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2003; 22:1127-1133. [PMID: 12729224 DOI: 10.1002/etc.5620220522] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the past 30 years, many amphibian species have suffered population declines throughout the world. Mass mortality have been frequently reported, and in several instances, infectious diseases appear to be the cause of death. The role that contaminants could play in these die-offs through immunotoxic effects has been poorly investigated. In this study, juvenile leopard frogs (Rana pipiens) were exposed for 21 d to a mixture of six pesticides (atrazine, metribuzin, aldicarb, endosulfane, lindane, and dieldrin) and subsequently challenged with a parasitic nematode, Rhabdias ranae. Exposure to the mixture at environmentally realistic concentrations significantly reduced lymphocyte proliferation. Three weeks after the end of the exposure, lymphocyte proliferation had recovered and was stimulated in frogs challenged with parasites with the exception of those previously exposed to the highest concentration. No pesticide effects on phagocytosis and splenocyte numbers were detectable at the end of the exposure period, but these two parameters were diminished 21 d after the infection challenge in frogs previously exposed to the highest levels of pesticides. In these animals, the prevalence of lung infection by R. ranae also tended to be higher. These results suggest that agricultural pesticides can alter the immune response of frogs and affect their ability to deal with parasitic infection.
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Affiliation(s)
- Marie-Soleil Christin
- INRS-Institut Armand-Frappier-Santé humaine, 245 Hymus Boulevard, Pointe-Claire, Quebec H9R 1G6, Canada
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Rollins-Smith LA, Carey C, Longcore J, Doersam JK, Boutte A, Bruzgal JE, Conlon JM. Activity of antimicrobial skin peptides from ranid frogs against Batrachochytrium dendrobatidis, the chytrid fungus associated with global amphibian declines. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2002; 26:471-479. [PMID: 11906726 DOI: 10.1016/s0145-305x(01)00088-x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Accumulating evidence suggests that a chytrid fungus, Batrachochytrium dendrobatidis, is responsible for recent declines in amphibian populations in Australia, Central America, Europe, and North America. Because the chytrid infects the keratinized epithelium of the skin, we investigated the possible role of antimicrobial peptides produced in the skin as inhibitors of infection and growth. We show here that 10 peptides representing eight families of peptides derived from North American ranid frogs can effectively inhibit growth of this chytrid. The peptides are members of the ranatuerin-1, ranatuerin-2, esculentin-1, esculentin-2, brevinin-2, temporin, palustrin-3, and ranalexin families. All the tested peptides inhibit growth of mature fungal cells at concentrations above 25 microM, and some of them inhibit at concentrations as low as 2 microM. A comparison of the sensitivity of infectious zoospores with that of mature cells showed that the zoospores are inhibited at significantly lower concentrations of peptides. To determine whether cold temperature interferes with the inhibitory effects of these peptides, we tested their effectiveness at both 22 and 10 degrees C. Although the peptides inhibit at both temperatures, they appear to be more effective against zoospores at the lower temperature. These results suggest that the ranid frogs have, within their repertoire of antimicrobial substances, a number of skin peptides that should be a deterrent to chytrid infection. This may provide some natural resistance to infection, but if environmental factors inhibit the synthesis and release of the skin peptides, the pathogen could gain the advantage.
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Affiliation(s)
- Louise A Rollins-Smith
- Departments of Microbiology and Immunology & Pediatrics, Vanderbilt University, Medical Center North, A-5301, Nashville, TN 37232, USA.
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Mondal S, Rai U. In vitro effect of temperature on phagocytic and cytotoxic activities of splenic phagocytes of the wall lizard, Hemidactylus flaviviridis. Comp Biochem Physiol A Mol Integr Physiol 2001; 129:391-8. [PMID: 11423311 DOI: 10.1016/s1095-6433(00)00356-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The in vitro effect of temperature on phagocytosis, nitric oxide production and interleukin-1 (IL-1) secretion by splenic phagocytes isolated from the wall lizard (Hemidactylus flaviviridis) demonstrated that changes in temperature altered non-specific defenses. The LPS-induced percentage phagocytosis and phagocytic index were recorded maximum at 25 degrees C. The phagocytic activity declined considerably when the phagocytes were incubated at low (7 and 15 degrees C) or high (37 degrees C) temperatures. The presence of bacterial lipopolysaccharide (LPS) in the incubation medium could considerably enhance the phagocytic activity of splenic phagocytes. A similar temperature-related effect was also observed on LPS-induced cytotoxic activity of phagocytes. LPS could stimulate the nitrite release indicating nitric oxide production only at 25 degrees C. Likewise, the proliferative responses of immature rat's thymocytes to LPS-induced phagocyte-conditioned medium suggest that IL-1 secretion was enhanced when phagocytes were cultured at 25 degrees C. This suggests that 25 degrees C is the optimal temperature for phagocyte functions in H. flaviviridis. The decrease or increase in temperature other than at 25 degrees C dramatically suppressed the phagocyte activities.
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Affiliation(s)
- S Mondal
- Department of Zoology, University of Delhi, Delhi 110007, India.
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Carey C, Cohen N, Rollins-Smith L. Amphibian declines: an immunological perspective. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1999; 23:459-72. [PMID: 10512457 DOI: 10.1016/s0145-305x(99)00028-2] [Citation(s) in RCA: 264] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Many, but not all, amphibian populations have been declining on all six continents on which they live. Although habitat destruction, direct application of toxicants, and introduction of predators/competitors are obvious causes of amphibian declines, many amphibians are dying of infectious diseases in relatively pristine habitats on several continents. In this paper, we review the patterns of these disease outbreaks and the characteristics of amphibian immune systems. Hypotheses are presented to explain the apparent susceptibility of amphibians to these pathogens. Natural and man-made factors that can alter amphibian immune responses to pathogens are discussed. Additional research is needed on the biology of the specific pathogens, the pattern of immune responses they elicit, and the nature of environmental stressors that may increase susceptibility to infectious disease.
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Affiliation(s)
- C Carey
- Department of EPO Biology, University of Colorado, Boulder 80309-0334, USA.
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George AJ, Ritter MA. Thymic involution with ageing: obsolescence or good housekeeping? IMMUNOLOGY TODAY 1996; 17:267-72. [PMID: 8962629 DOI: 10.1016/0167-5699(96)80543-3] [Citation(s) in RCA: 243] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- A J George
- Dept of Immunology, Royal Postgraduate Medical School, London, UK.
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Cooper EL, Parrinello N. Comparative immunologic models can enhance analyses of environmental immunotoxicity. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0959-8030(96)90013-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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