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Buckingham LJ, Ashby B. Coevolution of Age-Structured Tolerance and Virulence. Bull Math Biol 2024; 86:62. [PMID: 38662120 PMCID: PMC11045647 DOI: 10.1007/s11538-024-01292-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/03/2024] [Indexed: 04/26/2024]
Abstract
Hosts can evolve a variety of defences against parasitism, including resistance (which prevents or reduces the spread of infection) and tolerance (which protects against virulence). Some organisms have evolved different levels of tolerance at different life-stages, which is likely to be the result of coevolution with pathogens, and yet it is currently unclear how coevolution drives patterns of age-specific tolerance. Here, we use a model of tolerance-virulence coevolution to investigate how age structure influences coevolutionary dynamics. Specifically, we explore how coevolution unfolds when tolerance and virulence (disease-induced mortality) are age-specific compared to when these traits are uniform across the host lifespan. We find that coevolutionary cycling is relatively common when host tolerance is age-specific, but cycling does not occur when tolerance is the same across all ages. We also find that age-structured tolerance can lead to selection for higher virulence in shorter-lived than in longer-lived hosts, whereas non-age-structured tolerance always leads virulence to increase with host lifespan. Our findings therefore suggest that age structure can have substantial qualitative impacts on host-pathogen coevolution.
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Affiliation(s)
- Lydia J Buckingham
- Department of Mathematical Sciences, University of Bath, Bath, UK.
- Milner Centre for Evolution, University of Bath, Bath, UK.
| | - Ben Ashby
- Department of Mathematical Sciences, University of Bath, Bath, UK
- Milner Centre for Evolution, University of Bath, Bath, UK
- Department of Mathematics, Simon Fraser University, Burnaby, BC, Canada
- Pacific Institute on Pathogens, Pandemics and Society, Burnaby, BC, Canada
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2
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Malmberg JL, Allen SE, Jennings-Gaines JE, Johnson M, Luukkonen KL, Robbins KM, Cornish TE, Smiley RA, Wagler BL, Gregory Z, Lutz D, Hnilicka P, Monteith KL, Edwards WH. Pathology of Chronic Mycoplasma ovipneumoniae Carriers in a Declining Bighorn Sheep (Ovis canadensis) Population. J Wildl Dis 2024; 60:448-460. [PMID: 38329742 DOI: 10.7589/jwd-d-23-00132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 01/02/2024] [Indexed: 02/09/2024]
Abstract
Bighorn sheep (Ovis canadensis) across North America commonly experience population-limiting epizootics of respiratory disease. Although many cases of bighorn sheep pneumonia are polymicrobial, Mycoplasma ovipneumoniae is most frequently associated with all-age mortality events followed by years of low recruitment. Chronic carriage of M. ovipneumoniae by adult females serves as a source of exposure of naïve juveniles; relatively few ewes may be responsible for maintenance of infection within a herd. Test-and-remove strategies focused on removal of adult females with evidence of persistent or intermittent shedding (hereafter chronic carriers) may reduce prevalence and mitigate mortality. Postmortem confirmation of pneumonia in chronic carriers has been inadequately reported and the pathology has not been thoroughly characterized, limiting our understanding of important processes shaping the epidemiology of pneumonia in bighorn sheep. Here we document postmortem findings and characterize the lesions of seven ewes removed from a declining bighorn sheep population in Wyoming, USA, following at least two antemortem detections of M. ovipneumoniae within a 14-mo period. We confirmed that 6/7 (85.7%) had variable degrees of chronic pneumonia. Mycoplasma ovipneumoniae was detected in the lung of 4/7 (57.1%) animals postmortem. Four (57.1%) had paranasal sinus masses, all of which were classified as inflammatory, hyperplastic lesions. Pasteurella multocida was detected in all seven (100%) animals, while Trueperella pyogenes was detected in 5/7 (71.4%). Our findings indicate that not all chronic carriers have pneumonia, nor do all have detectable M. ovipneumoniae in the lung. Further, paranasal sinus masses are a common but inconsistent finding, and whether sinus lesions predispose to persistence or result from chronic carriage remains unclear. Our findings indicate that disease is variable in chronic M. ovipneumoniae carriers, underscoring the need for further efforts to characterize pathologic processes and underlying mechanisms in this system to inform management.
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Affiliation(s)
- Jennifer L Malmberg
- Department of Veterinary Sciences, University of Wyoming, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA
- Wyoming State Veterinary Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070
- Current affiliation and address: National Wildlife Research Center, Wildlife Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, 4101 LaPorte Avenue, Fort Collins, Colorado 80521, USA
| | - Samantha E Allen
- Wyoming Game and Fish Department, Veterinary Services, 1212 South Adams Street, Laramie, Wyoming 82070, USA
| | - Jessica E Jennings-Gaines
- Wyoming Game and Fish Department, Veterinary Services, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA
| | - Marguerite Johnson
- Wyoming Game and Fish Department, Veterinary Services, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA
| | - Katie L Luukkonen
- Wyoming Game and Fish Department, Veterinary Services, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA
| | - Kara M Robbins
- Wyoming Game and Fish Department, Veterinary Services, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA
| | - Todd E Cornish
- California Animal Health and Food Safety Lab, University of California-Davis, 18760 Road 112, Tulare, California 93274, USA
| | - Rachel A Smiley
- University of Wyoming, Haub School of the Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, 804 East Fremont Street, Laramie, Wyoming 82071, USA
| | - Brittany L Wagler
- University of Wyoming, Haub School of the Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, 804 East Fremont Street, Laramie, Wyoming 82071, USA
| | - Zach Gregory
- Wyoming Game and Fish Department, 260 Buena Vista Drive, Lander, Wyoming 82520, USA
| | - Daryl Lutz
- Wyoming Game and Fish Department, 260 Buena Vista Drive, Lander, Wyoming 82520, USA
| | - Pat Hnilicka
- US Fish and Wildlife Service, 170 North First Street, Lander, Wyoming 82520, USA
| | - Kevin L Monteith
- University of Wyoming, Haub School of the Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, 804 East Fremont Street, Laramie, Wyoming 82071, USA
| | - William H Edwards
- Wyoming Game and Fish Department, Veterinary Services, Wildlife Health Laboratory, 1174 Snowy Range Road, Laramie, Wyoming 82070, USA
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3
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Pfenning-Butterworth AC, Vetter RE, Hite JL. Natural variation in host feeding behaviors impacts host disease and pathogen transmission potential. Ecol Evol 2023; 13:e9865. [PMID: 36911315 PMCID: PMC9992943 DOI: 10.1002/ece3.9865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/09/2023] [Indexed: 03/10/2023] Open
Abstract
Animals ranging from mosquitoes to humans often vary their feeding behavior when infected or merely exposed to pathogens. These so-called "sickness behaviors" are part of the innate immune response with many consequences, including avoiding orally transmitted pathogens. Fully understanding the role of this ubiquitous behavior in host defense and pathogen evolution requires a quantitative account of its impact on host and pathogen fitness across environmentally relevant contexts. Here, we use a zooplankton host and fungal pathogen as a case study to ask if infection-mediated feeding behaviors vary across pathogen exposure levels and natural genetic variation in susceptibility to infection. Then, we connect these changes in behavior to pathogen transmission potential (spore yield) and fitness and growth costs to the host. Our results validate a protective effect of altered feeding behavior during pathogen exposure while also revealing significant variation in the magnitude of this response across host susceptibility and pathogen exposure levels. Across all four host genotypes, feeding rates were negatively correlated with susceptibility to infection and transmission potential. The most susceptible genotypes exhibited either strong anorexia, reducing food intake by 26%-42%, ("Standard") or pronounced hyperphagia, increasing food intake by 20%-54% ("A45"). Together, these results suggest that infection-mediated changes in host feeding behavior-which are traditionally interpreted as immunopathology- may in fact serve as crucial components of host defense strategies and warrant further investigation.
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Affiliation(s)
- Alaina C Pfenning-Butterworth
- School of Biological Sciences University of Nebraska Lincoln Nebraska USA.,Department of Botany University of British Columbia Vancouver British Columbia Canada
| | - Rachel E Vetter
- School of Biological Sciences University of Nebraska Lincoln Nebraska USA
| | - Jessica L Hite
- School of Biological Sciences University of Nebraska Lincoln Nebraska USA.,Department of Pathobiological Sciences University of Wisconsin Madison Wisconsin USA
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4
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Fracasso G, Matthysen E, Heylen D. Heritable variation in host quality as measured through an ectoparasite's performance. OIKOS 2021. [DOI: 10.1111/oik.08824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | | | - Dieter Heylen
- Interuniversity Inst. for Biostatistics and Statistical Bioinformatics, Hasselt Univ. Diepenbeek Belgium
- Eco‐Epidemiology Group, Dept of Biomedical Sciences, Inst. of Tropical Medicine Antwerp Belgium
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5
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Marian V, Bartolotti J, Daniel NL, Hayakawa S. Spoken words activate native and non-native letter-to-sound mappings: Evidence from eye tracking. BRAIN AND LANGUAGE 2021; 223:105045. [PMID: 34741984 PMCID: PMC8633124 DOI: 10.1016/j.bandl.2021.105045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
Many languages use the same letters to represent different sounds (e.g., the letter P represents /p/ in English but /r/ in Russian). We report two experiments that examine how native language experience impacts the acquisition and processing of words with conflicting letter-to-sound mappings. Experiment 1 revealed that individual differences in nonverbal intelligence predicted word learning and that novel words with conflicting orthography-to-phonology mappings were harder to learn when their spelling was more typical of the native language than less typical (due to increased competition from the native language). Notably, Experiment 2 used eye tracking to reveal, for the first time, that hearing non-native spoken words activates native language orthography and both native and non-native letter-to-sound mappings. These findings evince high interactivity in the language system, illustrate the role of orthography in phonological learning and processing, and demonstrate that experience with written form changes the linguistic mind.
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6
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Singh P, Best A. Simultaneous evolution of host resistance and tolerance to parasitism. J Evol Biol 2021; 34:1932-1943. [PMID: 34704334 DOI: 10.1111/jeb.13947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 09/17/2021] [Accepted: 10/11/2021] [Indexed: 12/22/2022]
Abstract
Tolerance and resistance are two modes of defence mechanisms used by hosts when faced with parasites. Here, we assume tolerance reduces infection-induced mortality rate and resistance reduces the susceptibility of getting infected. Importantly, a negative association between these two strategies has often been found experimentally. We study the simultaneous evolution of resistance and tolerance in a host population where they are related by such a trade-off. Using evolutionary invasion theory, we examine the patterns of optimal investment in each defence strategy, under different ecological scenarios. Our focus is on predicting which of the two strategies is favoured under various epidemiological and ecological conditions. Our key findings surround the impact of recovery and sterility of infected hosts. As the rate at which infected hosts recover from the infection, that is the recovery rate increases, the investment in tolerance increases (resistance decreases) when infected hosts are sterile, but this pattern reverses when infected hosts can reproduce. We further found that a change in the parameter determining the intraspecies competition for resources leading to a reduction in birth rate, that is the crowding factor affects investments in tolerance and resistance only when infected hosts can reproduce. These results emphasize the role of fecundity in driving the evolutionary dynamics of a host. We also find that disease prevalence can increase or decrease depending on whether or not the host evolves: prevalence is highest at low recovery rates when the host does not evolve, but the feedback of a change in tolerance and resistance reverses this pattern, leading to lower prevalence at low recovery rates as host evolves.
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Affiliation(s)
- Prerna Singh
- School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
| | - Alex Best
- School of Mathematics and Statistics, University of Sheffield, Sheffield, UK
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7
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Duffin P, Martin DL, Furman BT, Ross C. Spatial Patterns of Thalassia testudinum Immune Status and Labyrinthula spp. Load Implicate Environmental Quality and History as Modulators of Defense Strategies and Wasting Disease in Florida Bay, United States. FRONTIERS IN PLANT SCIENCE 2021; 12:612947. [PMID: 33613601 PMCID: PMC7892610 DOI: 10.3389/fpls.2021.612947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Seagrass wasting disease, caused by protists of the genus Labyrinthula, is an important stressor of the dominant macrophyte in Florida Bay (FB), United States, Thalassia testudinum. FB exhibits countervailing gradients in plant morphology and resource availability. A synoptic picture of the Thalassia-Labyrinthula relationship was obtained by assessing the activity of four immune biomarkers in conjunction with pathogen prevalence and load [via quantitative PCR (qPCR)] at 15 sites across FB. We found downregulated immune status paired with moderate pathogen load among larger-bodied host phenotypes in western FB and upregulated immunity for smaller-bodied phenotypes in eastern FB. Among the highest immune response sites, a distinct inshore-offshore loading pattern was observed, where coastal basins exposed to freshwater runoff and riverine inputs had the highest pathogen loads, while adjacent offshore locations had the lowest. To explain this, we propose a simple, conceptual model that defines a framework for testable hypotheses based on recent advances in resistance-tolerance theory. We suggest that resource availability has the potential to drive not only plant size, but also tolerance to pathogen load by reducing investment in immunity. Where resources are more scarce, plants may adopt a resistance strategy, upregulating immunity; however, when physiologically challenged, this strategy appears to fail, resulting in high pathogen load. While evidence remains correlative, we argue that hyposalinity stress, at one or more temporal scales, may represent one of many potential drivers of disease dynamics in FB. Together, these data highlight the complexity of the wasting disease pathosystem and raise questions about how climate change and ongoing Everglades restoration might impact this foundational seagrass species.
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Affiliation(s)
- Paige Duffin
- Department of Biology, University of North Florida, Jacksonville, FL, United States
- Department of Genetics, University of Georgia, Athens, GA, United States
| | - Daniel L. Martin
- Department of Biology, University of North Florida, Jacksonville, FL, United States
| | - Bradley T. Furman
- Florida Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL, United States
| | - Cliff Ross
- Department of Biology, University of North Florida, Jacksonville, FL, United States
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8
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Balard A, Jarquín‐Díaz VH, Jost J, Mittné V, Böhning F, Ďureje Ľ, Piálek J, Heitlinger E. Coupling between tolerance and resistance for two related Eimeria parasite species. Ecol Evol 2020; 10:13938-13948. [PMID: 33391692 PMCID: PMC7771152 DOI: 10.1002/ece3.6986] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 09/29/2020] [Accepted: 10/16/2020] [Indexed: 12/19/2022] Open
Abstract
Resistance (host capacity to reduce parasite burden) and tolerance (host capacity to reduce impact on its health for a given parasite burden) manifest two different lines of defense. Tolerance can be independent from resistance, traded off against it, or the two can be positively correlated because of redundancy in underlying (immune) processes. We here tested whether this coupling between tolerance and resistance could differ upon infection with closely related parasite species. We tested this in experimental infections with two parasite species of the genus Eimeria. We measured proxies for resistance (the (inverse of) number of parasite transmission stages (oocysts) per gram of feces at the day of maximal shedding) and tolerance (the slope of maximum relative weight loss compared to day of infection on number of oocysts per gram of feces at the day of maximal shedding for each host strain) in four inbred mouse strains and four groups of F1 hybrids belonging to two mouse subspecies, Mus musculus domesticus and Mus musculus musculus. We found a negative correlation between resistance and tolerance against Eimeria falciformis, while the two are uncoupled against Eimeria ferrisi. We conclude that resistance and tolerance against the first parasite species might be traded off, but evolve more independently in different mouse genotypes against the latter. We argue that evolution of the host immune defenses can be studied largely irrespective of parasite isolates if resistance-tolerance coupling is absent or weak (E. ferrisi) but host-parasite coevolution is more likely observable and best studied in a system with negatively correlated tolerance and resistance (E. falciformis).
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Affiliation(s)
- Alice Balard
- Department of Molecular ParasitologyInstitute for BiologyHumboldt University Berlin (HU)BerlinGermany
- Leibniz‐Institut für Zoo‐ und Wildtierforschung (IZW) im Forschungsverbund Berlin e.V.BerlinGermany
| | - Víctor Hugo Jarquín‐Díaz
- Department of Molecular ParasitologyInstitute for BiologyHumboldt University Berlin (HU)BerlinGermany
- Leibniz‐Institut für Zoo‐ und Wildtierforschung (IZW) im Forschungsverbund Berlin e.V.BerlinGermany
| | - Jenny Jost
- Department of Molecular ParasitologyInstitute for BiologyHumboldt University Berlin (HU)BerlinGermany
| | - Vivian Mittné
- Department of Molecular ParasitologyInstitute for BiologyHumboldt University Berlin (HU)BerlinGermany
| | - Francisca Böhning
- Department of Molecular ParasitologyInstitute for BiologyHumboldt University Berlin (HU)BerlinGermany
| | - Ľudovít Ďureje
- Research Facility StudenecInstitute of Vertebrate BiologyCzech Academy of SciencesBrnoCzech Republic
| | - Jaroslav Piálek
- Research Facility StudenecInstitute of Vertebrate BiologyCzech Academy of SciencesBrnoCzech Republic
| | - Emanuel Heitlinger
- Department of Molecular ParasitologyInstitute for BiologyHumboldt University Berlin (HU)BerlinGermany
- Leibniz‐Institut für Zoo‐ und Wildtierforschung (IZW) im Forschungsverbund Berlin e.V.BerlinGermany
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9
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El-Helow ER, Atalla RG, Sabra WA, Lotfy WA. Kinetic studies on the expression of alginate and extracellular proteins by Pseudomonas aeruginosa FRD1 and PAO1. J GEN APPL MICROBIOL 2019; 66:15-23. [PMID: 31366850 DOI: 10.2323/jgam.2019.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Pseudomonas aeruginosa is characterized by its capability to produce extracellular virulence proteins and to establish biofilm-based infections that do not respond easily to conventional treatments. However, the physiological conditions that decrease the fitness of such a persistent pathogen would assist the host to defend itself and reduce the infection prevalence. Therefore, developing treatments against P. aeruginosa requires a quantitative understanding of the relationship between bacterial growth kinetics and secretion of alginate and proteins, in addition to the ecological factors that control their synthesis. For this purpose, we examined various environmental factors that affect the specific product yield coefficients (expressed as g product/OD600) of alginate and extracellular proteins using a mucoid (FRD1) and a non-mucoid (PAO1) clinical isolate of P. aeruginosa, respectively. The results suggested magnesium sulfate, trace elements and hydrogen peroxide as significant variables that positively affect alginate synthesis by the FRD1 cells. However, the production of extracellular proteins by PAO1 was negatively affected by the concentration of ferrous sulfate. For understanding the kinetics of expressing alginate and extracellular proteins by the cells, a well-controlled 5 L tank bioreactor was used. The results suggested that under the bioreactor controlled conditions, both alginate and extracellular proteins are expressed parallel to biomass increase in the cells of P. aeruginosa.
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Affiliation(s)
- Ehab R El-Helow
- Department of Botany and Microbiology, Faculty of Science, Alexandria University
| | - Ramy G Atalla
- Department of Botany and Microbiology, Faculty of Science, Alexandria University
| | - Wael A Sabra
- Department of Botany and Microbiology, Faculty of Science, Alexandria University
| | - Walid A Lotfy
- Microbiology Department, Faculty of Dentistry, Pharos University in Alexandria
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10
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Rutter L, Carrillo-Tripp J, Bonning BC, Cook D, Toth AL, Dolezal AG. Transcriptomic responses to diet quality and viral infection in Apis mellifera. BMC Genomics 2019; 20:412. [PMID: 31117959 PMCID: PMC6532243 DOI: 10.1186/s12864-019-5767-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 05/03/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Parts of Europe and the United States have witnessed dramatic losses in commercially managed honey bees over the past decade to what is considered an unsustainable extent. The large-scale loss of bees has considerable implications for the agricultural economy because bees are one of the leading pollinators of numerous crops. Bee declines have been associated with several interactive factors. Recent studies suggest nutritional and pathogen stress can interactively contribute to bee physiological declines, but the molecular mechanisms underlying interactive effects remain unknown. In this study, we provide insight into this question by using RNA-sequencing to examine how monofloral diets and Israeli acute paralysis virus inoculation influence gene expression patterns in bees. RESULTS We found a considerable nutritional response, with almost 2000 transcripts changing with diet quality. The majority of these genes were over-represented for nutrient signaling (insulin resistance) and immune response (Notch signaling and JaK-STAT pathways). In our experimental conditions, the transcriptomic response to viral infection was fairly limited. We only found 43 transcripts to be differentially expressed, some with known immune functions (argonaute-2), transcriptional regulation, and muscle contraction. We created contrasts to explore whether protective mechanisms of good diet were due to direct effects on immune function (resistance) or indirect effects on energy availability (tolerance). A similar number of resistance and tolerance candidate differentially expressed genes were found, suggesting both processes may play significant roles in dietary buffering from pathogen infection. CONCLUSIONS Through transcriptional contrasts and functional enrichment analysis, we contribute to our understanding of the mechanisms underlying feedbacks between nutrition and disease in bees. We also show that comparing results derived from combined analyses across multiple RNA-seq studies may allow researchers to identify transcriptomic patterns in bees that are concurrently less artificial and less noisy. This work underlines the merits of using data visualization techniques and multiple datasets to interpret RNA-sequencing studies.
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Affiliation(s)
- Lindsay Rutter
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, 50011, IA, USA
| | - Jimena Carrillo-Tripp
- Department of Microbiology, Center for Scientific Research and Higher Education of Ensenada, Ensenada, 22860, Baja California, Mexico
| | - Bryony C Bonning
- Department of Entomology and Nematology, University of Florida, Gainesville, 32611, FL, USA
| | - Dianne Cook
- Econometrics and Business Statistics, Monash University, Clayton, 3800, VIC, Australia
| | - Amy L Toth
- Department of Entomology, Iowa State University, Ames, 50011, IA, USA.,Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, 50011, IA, USA
| | - Adam G Dolezal
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, 61801, IL, USA.
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11
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Budischak SA, Cressler CE. Fueling Defense: Effects of Resources on the Ecology and Evolution of Tolerance to Parasite Infection. Front Immunol 2018; 9:2453. [PMID: 30429848 PMCID: PMC6220035 DOI: 10.3389/fimmu.2018.02453] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Accepted: 10/04/2018] [Indexed: 12/29/2022] Open
Abstract
Resource availability is a key environmental constraint affecting the ecology and evolution of species. Resources have strong effects on disease resistance, but they can also affect the other main parasite defense strategy, tolerance. A small but growing number of animal studies are beginning to investigate the effects of resources on tolerance phenotypes. Here, we review how resources affect tolerance strategies across animal taxa ranging from fruit flies to frogs to mice. Surprisingly, resources (quality and quantity) can increase or reduce tolerance, dependent upon the particular host-parasite system. To explore this seeming contradiction, we recast predictions of models of sterility tolerance and mortality tolerance in a resource-dependent context. Doing so reveals that resources can have very different epidemiological and evolutionary effects, depending on what aspects of the tolerance phenotype are affected. Thus, it is critical to consider both sterility and mortality in future empirical studies of how behavioral and environmental resource availability affect tolerance to infection.
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Affiliation(s)
- Sarah A. Budischak
- W. M. Keck Science Department of Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, United States
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, United States
| | - Clayton E. Cressler
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
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12
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Bartolotti J, Marian V. Learning and processing of orthography-to-phonology mappings in a third language. INTERNATIONAL JOURNAL OF MULTILINGUALISM 2018; 16:377-397. [PMID: 32863774 PMCID: PMC7451201 DOI: 10.1080/14790718.2017.1423073] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 12/27/2017] [Indexed: 06/11/2023]
Abstract
Bilinguals' two languages are both active in parallel, and controlling co-activation is one of bilinguals' principle challenges. Trilingualism multiplies this challenge. To investigate how third language (L3) learners manage interference between languages, Spanish-English bilinguals were taught an artificial language that conflicted with English and Spanish letter-sound mappings. Interference from existing languages was higher for L3 words that were similar to L1 or L2 words, but this interference decreased over time. After mastering the L3, learners continued to experience competition from their other languages. Notably, spoken L3 words activated orthography in all three languages, causing participants to experience cross-linguistic orthographic competition in the absence of phonological overlap. Results indicate that L3 learners are able to control between-language interference from the L1 and L2. We conclude that while the transition from two languages to three presents additional challenges, bilinguals are able to successfully manage competition between languages in this new context.
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Affiliation(s)
- James Bartolotti
- Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA
| | - Viorica Marian
- Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA
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13
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Yamamichi M, Ellner SP. Antagonistic coevolution between quantitative and Mendelian traits. Proc Biol Sci 2016; 283:20152926. [PMID: 27009218 DOI: 10.1098/rspb.2015.2926] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/24/2016] [Indexed: 11/12/2022] Open
Abstract
Coevolution is relentlessly creating and maintaining biodiversity and therefore has been a central topic in evolutionary biology. Previous theoretical studies have mostly considered coevolution between genetically symmetric traits (i.e. coevolution between two continuous quantitative traits or two discrete Mendelian traits). However, recent empirical evidence indicates that coevolution can occur between genetically asymmetric traits (e.g. between quantitative and Mendelian traits). We examine consequences of antagonistic coevolution mediated by a quantitative predator trait and a Mendelian prey trait, such that predation is more intense with decreased phenotypic distance between their traits (phenotype matching). This antagonistic coevolution produces a complex pattern of bifurcations with bistability (initial state dependence) in a two-dimensional model for trait coevolution. Furthermore, with eco-evolutionary dynamics (so that the trait evolution affects predator-prey population dynamics), we find that coevolution can cause rich dynamics including anti-phase cycles, in-phase cycles, chaotic dynamics and deterministic predator extinction. Predator extinction is more likely to occur when the prey trait exhibits complete dominance rather than semidominance and when the predator trait evolves very rapidly. Our study illustrates how recognizing the genetic architectures of interacting ecological traits can be essential for understanding the population and evolutionary dynamics of coevolving species.
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Affiliation(s)
- Masato Yamamichi
- Hakubi Center for Advanced Research, Kyoto University, Sakyo, Kyoto 606-8501, Japan Center for Ecological Research, Kyoto University, Otsu, Shiga 520-2113, Japan Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Stephen P Ellner
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
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14
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Goic B, Stapleford KA, Frangeul L, Doucet AJ, Gausson V, Blanc H, Schemmel-Jofre N, Cristofari G, Lambrechts L, Vignuzzi M, Saleh MC. Virus-derived DNA drives mosquito vector tolerance to arboviral infection. Nat Commun 2016; 7:12410. [PMID: 27580708 PMCID: PMC5025746 DOI: 10.1038/ncomms12410] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 06/29/2016] [Indexed: 02/06/2023] Open
Abstract
Mosquitoes develop long-lasting viral infections without substantial deleterious effects, despite high viral loads. This makes mosquitoes efficient vectors for emerging viral diseases with enormous burden on public health. How mosquitoes resist and/or tolerate these viruses is poorly understood. Here we show that two species of Aedes mosquitoes infected with two arboviruses from distinct families (dengue or chikungunya) generate a viral-derived DNA (vDNA) that is essential for mosquito survival and viral tolerance. Inhibition of vDNA formation leads to extreme susceptibility to viral infections, reduction of viral small RNAs due to an impaired immune response, and loss of viral tolerance. Our results highlight an essential role of vDNA in viral tolerance that allows mosquito survival and thus may be important for arbovirus dissemination and transmission. Elucidating the mechanisms of mosquito tolerance to arbovirus infection paves the way to conceptualize new antivectorial strategies to selectively eliminate arbovirus-infected mosquitoes.
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Affiliation(s)
- Bertsy Goic
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
| | - Kenneth A. Stapleford
- Institut Pasteur, Viral Populations and Pathogenesis Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
| | - Lionel Frangeul
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
| | - Aurélien J. Doucet
- IRCAN, INSERM U1081, Centre National de la Recherche Scientifique UMR 7284, University of Nice—Sophia-Antipolis, 06107 Nice Cedex 2, France
| | - Valérie Gausson
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
| | - Hervé Blanc
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
- Institut Pasteur, Viral Populations and Pathogenesis Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
| | - Nidia Schemmel-Jofre
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
| | - Gael Cristofari
- IRCAN, INSERM U1081, Centre National de la Recherche Scientifique UMR 7284, University of Nice—Sophia-Antipolis, 06107 Nice Cedex 2, France
- FHU OncoAge, University of Nice-Sophia Antipolis, 06107 Nice, France
| | - Louis Lambrechts
- Institut Pasteur, Insect-Virus Interactions Group, Centre National de la Recherche Scientifique URA 3012, 75724 Paris cedex 15, France
| | - Marco Vignuzzi
- Institut Pasteur, Viral Populations and Pathogenesis Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
| | - Maria-Carla Saleh
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, 75724 Paris cedex 15, France
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15
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Hamede RK, Pearse AM, Swift K, Barmuta LA, Murchison EP, Jones ME. Transmissible cancer in Tasmanian devils: localized lineage replacement and host population response. Proc Biol Sci 2016; 282:rspb.2015.1468. [PMID: 26336167 DOI: 10.1098/rspb.2015.1468] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Tasmanian devil facial tumour disease (DFTD) is a clonally transmissible cancer threatening the Tasmanian devil (Sarcophilus harrisii) with extinction. Live cancer cells are the infectious agent, transmitted to new hosts when individuals bite each other. Over the 18 years since DFTD was first observed, distinct genetic and karyotypic sublineages have evolved. In this longitudinal study, we investigate the associations between tumour karyotype, epidemic patterns and host demographic response to the disease. Reduced host population effects and low DFTD infection rates were associated with high prevalence of tetraploid tumours. Subsequent replacement by a diploid variant of DFTD coincided with a rapid increase in disease prevalence, population decline and reduced mean age of the population. Our results suggest a role for tumour genetics in DFTD transmission dynamics and epidemic outcome. Future research, for this and other highly pathogenic emerging infectious diseases, should focus on understanding the evolution of host and pathogen genotypes, their effects on susceptibility and tolerance to infection, and their implications for designing novel genetic management strategies. This study provides evidence for a rapid localized lineage replacement occurring within a transmissible cancer epidemic and highlights the possibility that distinct DFTD genetic lineages may harbour traits that influence pathogen fitness.
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Affiliation(s)
- Rodrigo K Hamede
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
| | - Anne-Maree Pearse
- Department of Primary Industries, Parks, Water and Environment, Hobart, Tasmania 7001, Australia
| | - Kate Swift
- Department of Primary Industries, Parks, Water and Environment, Hobart, Tasmania 7001, Australia
| | - Leon A Barmuta
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
| | - Elizabeth P Murchison
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Menna E Jones
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
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16
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Restif O, Graham AL. Within-host dynamics of infection: from ecological insights to evolutionary predictions. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0304. [PMID: 26150670 PMCID: PMC4528502 DOI: 10.1098/rstb.2014.0304] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Olivier Restif
- Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Andrea L Graham
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
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17
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Cressler CE, Graham AL, Day T. Evolution of hosts paying manifold costs of defence. Proc Biol Sci 2015; 282:20150065. [PMID: 25740895 DOI: 10.1098/rspb.2015.0065] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Hosts are expected to incur several physiological costs in defending against parasites. These include constitutive energetic (or other resource) costs of a defence system, facultative resource costs of deploying defences when parasites strike, and immunopathological costs of collateral damage. Here, we investigate the evolution of host recovery rates, varying the source and magnitude of immune costs. In line with previous work, we find that hosts paying facultative resource costs evolve faster recovery rates than hosts paying constitutive costs. However, recovery rate is more sensitive to changes in facultative costs, potentially explaining why constitutive costs are hard to detect empirically. Moreover, we find that immunopathology costs which increase with recovery rate can erode the benefits of defence, promoting chronicity of infection. Immunopathology can also lead to hosts evolving low recovery rate in response to virulent parasites. Furthermore, when immunopathology reduces fecundity as recovery rate increases (e.g. as for T-cell responses to urogenital chlamydiosis), then recovery and reproductive rates do not covary as predicted in eco-immunology. These results suggest that immunopathological and resource costs have qualitatively different effects on host evolution and that embracing the complexity of immune costs may be essential for explaining variability in immune defence in nature.
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Affiliation(s)
- Clayton E Cressler
- Department of Mathematics and Statistics, Queen's University, Kingston, Ontario, Canada K7L 3N6
| | - Andrea L Graham
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Troy Day
- Department of Mathematics and Statistics, Queen's University, Kingston, Ontario, Canada K7L 3N6 Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6
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18
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McLeod DV, Day T. Pathogen evolution under host avoidance plasticity. Proc Biol Sci 2015; 282:20151656. [PMID: 26336170 PMCID: PMC4571713 DOI: 10.1098/rspb.2015.1656] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/05/2015] [Indexed: 11/12/2022] Open
Abstract
Host resistance consists of defences that limit pathogen burden, and can be classified as either adaptations targeting recovery from infection or those focused upon infection avoidance. Conventional theory treats avoidance as a fixed strategy which does not vary from one interaction to the next. However, there is increasing empirical evidence that many avoidance strategies are triggered by external stimuli, and thus should be treated as phenotypically plastic responses. Here, we consider the implications of avoidance plasticity for host-pathogen coevolution. We uncover a number of predictions challenging current theory. First, in the absence of pathogen trade-offs, plasticity can restrain pathogen evolution; moreover, the pathogen exploits conditions in which the host would otherwise invest less in resistance, causing resistance escalation. Second, when transmission trades off with pathogen-induced mortality, plasticity encourages avirulence, resulting in a superior fitness outcome for both host and pathogen. Third, plasticity ensures the sterilizing effect of pathogens has consequences for pathogen evolution. When pathogens castrate hosts, selection forces them to minimize mortality virulence; moreover, when transmission trades off with sterility alone, resistance plasticity is sufficient to prevent pathogens from evolving to fully castrate.
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Affiliation(s)
- David V McLeod
- Department of Mathematics and Statistics, Queen's University, 99 University Avenue, Kingston, Ontario, Canada K7 L 3N6
| | - Troy Day
- Department of Mathematics and Statistics, Queen's University, 99 University Avenue, Kingston, Ontario, Canada K7 L 3N6
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19
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Zueva KJ, Lumme J, Veselov AE, Kent MP, Lien S, Primmer CR. Footprints of directional selection in wild Atlantic salmon populations: evidence for parasite-driven evolution? PLoS One 2014; 9:e91672. [PMID: 24670947 PMCID: PMC3966780 DOI: 10.1371/journal.pone.0091672] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 02/14/2014] [Indexed: 12/15/2022] Open
Abstract
Mechanisms of host-parasite co-adaptation have long been of interest in evolutionary biology; however, determining the genetic basis of parasite resistance has been challenging. Current advances in genome technologies provide new opportunities for obtaining a genome-scale view of the action of parasite-driven natural selection in wild populations and thus facilitate the search for specific genomic regions underlying inter-population differences in pathogen response. European populations of Atlantic salmon (Salmo salar L.) exhibit natural variance in susceptibility levels to the ectoparasite Gyrodactylus salaris Malmberg 1957, ranging from resistance to extreme susceptibility, and are therefore a good model for studying the evolution of virulence and resistance. However, distinguishing the molecular signatures of genetic drift and environment-associated selection in small populations such as land-locked Atlantic salmon populations presents a challenge, specifically in the search for pathogen-driven selection. We used a novel genome-scan analysis approach that enabled us to i) identify signals of selection in salmon populations affected by varying levels of genetic drift and ii) separate potentially selected loci into the categories of pathogen (G. salaris)-driven selection and selection acting upon other environmental characteristics. A total of 4631 single nucleotide polymorphisms (SNPs) were screened in Atlantic salmon from 12 different northern European populations. We identified three genomic regions potentially affected by parasite-driven selection, as well as three regions presumably affected by salinity-driven directional selection. Functional annotation of candidate SNPs is consistent with the role of the detected genomic regions in immune defence and, implicitly, in osmoregulation. These results provide new insights into the genetic basis of pathogen susceptibility in Atlantic salmon and will enable future searches for the specific genes involved.
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Affiliation(s)
- Ksenia J. Zueva
- Department of Biology, University of Turku, Turku, Finland
- * E-mail:
| | - Jaakko Lumme
- Department of Biology, University of Oulu, Oulu, Finland
| | - Alexey E. Veselov
- Institute of Biology, Karelian Research Centre of RAS, Petrozavodsk, Russia
| | - Matthew P. Kent
- Centre for Integrative Genetics (CIGENE) and Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, Norway
| | - Sigbjørn Lien
- Centre for Integrative Genetics (CIGENE) and Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, Norway
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20
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Mazé-Guilmo E, Loot G, Páez DJ, Lefèvre T, Blanchet S. Heritable variation in host tolerance and resistance inferred from a wild host-parasite system. Proc Biol Sci 2014; 281:20132567. [PMID: 24478295 DOI: 10.1098/rspb.2013.2567] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hosts have evolved two distinct defence strategies against parasites: resistance (which prevents infection or limit parasite growth) and tolerance (which alleviates the fitness consequences of infection). However, heritable variation in resistance and tolerance and the genetic correlation between these two traits have rarely been characterized in wild host populations. Here, we estimate these parameters for both traits in Leuciscus burdigalensis, a freshwater fish parasitized by Tracheliastes polycolpus. We used a genetic database to construct a full-sib pedigree in a wild L. burdigalensis population. We then used univariate animal models to estimate inclusive heritability (i.e. all forms of genetic and non-genetic inheritance) in resistance and tolerance. Finally, we assessed the genetic correlation between these two traits using a bivariate animal model. We found significant heritability for resistance (H = 17.6%; 95% CI: 7.2-32.2%) and tolerance (H = 18.8%; 95% CI: 4.4-36.1%), whereas we found no evidence for the existence of a genetic correlation between these traits. Furthermore, we confirm that resistance and tolerance are strongly affected by environmental effects. Our results demonstrate that (i) heritable variation exists for parasite resistance and tolerance in wild host populations, and (ii) these traits can evolve independently in populations.
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Affiliation(s)
- Elise Mazé-Guilmo
- Centre National de la Recherche Scientifique (CNRS), Station d'Ecologie Expérimentale du CNRS à Moulis, , USR 2936, 09200 Moulis, France, Université de Toulouse, , UPS, UMR5174 EDB (Laboratoire Évolution and Diversité Biologique), 118 route de Narbonne, 31062 Toulouse Cedex, France, Department of Ecology and Evolution, University of Chicago, , 1101 E 57th Street, Erman 103, Chicago, IL 60637, USA, Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC) UMR (IRD/CNRS/UM) 5290, , Centre IRD-911 Avenue Agropolis, BP 64501 Montpellier, France, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier, École Nationale de Formation Agronomique (ENFA), UMR5174 EDB (Laboratoire Évolution and Diversité Biologique), , 118 route de Narbonne, 31062 Toulouse Cedex 4, France
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21
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Němejc K, Sak B, Květoňová D, Hanzal V, Janiszewski P, Forejtek P, Rajský D, Ravaszová P, McEvoy J, Kváč M. Cryptosporidium suis and Cryptosporidium scrofarum in Eurasian wild boars (Sus scrofa) in Central Europe. Vet Parasitol 2013; 197:504-8. [PMID: 23916060 PMCID: PMC4437658 DOI: 10.1016/j.vetpar.2013.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 06/10/2013] [Accepted: 07/03/2013] [Indexed: 11/23/2022]
Abstract
From 2011 to 2012, to identify Cryptosporidium spp. occurrence in Eurasian wild boars (Sus scrofa) 29 randomly selected localities (both forest areas and enclosures) across the Central European countries of Austria, the Czech Republic, Poland, and the Slovak Republic were investigated. Cryptosporidium oocysts were microscopicaly detected in 11 out of 460 faecal samples examined using aniline-carbol-methyl violet staining. Sixty-one Cryptosporidium infections, including the 11 infections that were detected by microscopy, were detected using genus- or species-specific nested PCR amplification of SSU rDNA. This represents a 5.5 fold greater sensitivity for PCR relative to microscopy. Combining genus- and species-specific PCR tools significantly changes the perspective on the occurrence of Cryptosporidium spp. in wild boars. While RFLP and direct sequencing of genus specific PCR-amplified products revealed 56 C. suis (20) and C. scrofarum (36) monoinfections and only 5 mixed infections of these species, species-specific molecular tools showed 44 monoinfections and 17 mixed infections with these species. PCR analysis of the gp60 gene did not reveal any other Cryptosporidium infections. Similar to domestic pigs, C. scrofarum was detected as a dominant species infecting adult Eurasian wild boars (Sus scrofa). Cryptosporidium infected wild boars did not show signs of clinical disease. This report is perhaps the most comprehensive survey of cryptosporidial infection in wild boars.
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Affiliation(s)
- Karel Němejc
- Faculty of Agriculture, University of South Bohemia in České Budějovice, Studentská 13, 370 05 České Budějovice, Czech Republic
| | - Bohumil Sak
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Dana Květoňová
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Vladimír Hanzal
- Faculty of Agriculture, University of South Bohemia in České Budějovice, Studentská 13, 370 05 České Budějovice, Czech Republic
- Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6 – Suchdol, Czech Republic
| | - Paweł Janiszewski
- Faculty of Animal Bioengineering, University of Warmia and Mazury, M. Oczapowskiego 5, 10-718 Olsztyn-Kortowo, Poland
| | - Pavel Forejtek
- Institute for Wildlife Ecology, University of Veterinary and Pharmaceutical Sciences Brno, Palackého 1-3, 612 42 Brno, Czech Republic
| | - Dušan Rajský
- Faculty of Forestry, Technical University in Zvolen, T. G. Masaryka 2117/24, 960 53 Zvolen, Slovak Republic
| | - Petra Ravaszová
- Department of Biology and Genetics, University of Veterinary Medicine and Pharmacy in Košice, Komenského 73, 041 81 Košice, Slovak Republic
| | - John McEvoy
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND, USA
| | - Martin Kváč
- Faculty of Agriculture, University of South Bohemia in České Budějovice, Studentská 13, 370 05 České Budějovice, Czech Republic
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, Branišovská 31, 370 05 České Budějovice, Czech Republic
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22
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Restif O. An offer you cannot refuse: down-regulation of immunity in response to a pathogen's retaliation threat. J Evol Biol 2013; 26:2021-30. [PMID: 23927686 PMCID: PMC4274018 DOI: 10.1111/jeb.12209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/16/2013] [Accepted: 05/28/2013] [Indexed: 12/15/2022]
Abstract
According to the Red Queen hypothesis, hosts and pathogens are engaged in an escalating coevolutionary arms race between resistance and virulence. However, the vast majority of symbionts colonize their hosts' mucosal compartments without triggering any immune response, resulting in durable commensal associations. Here, I propose a simple extension of previous mathematical models for antagonistic coevolution in which the host can mount a delayed immune response; in response, the symbiont can change its virulence following this activation. Even though the levels of virulence in both phases are assumed to be genetically determined, this simple form of plasticity can select for commensal associations. In particular, coevolution can result in hosts that do not activate their immune response, thus preventing phenotypically plastic pathogens from switching to a higher virulence level. I argue that, from the host's point of view, this state is analogous to the mafia behaviour previously described in avian brood parasites. More importantly, this study provides a new hypothesis for the maintenance of a commensal relationship through antagonistic coevolution.
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Affiliation(s)
- O Restif
- Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK.
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23
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Dances with worms: the ecological and evolutionary impacts of deworming on coinfecting pathogens. Parasitology 2013; 140:1119-32. [PMID: 23714427 PMCID: PMC3695730 DOI: 10.1017/s0031182013000590] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Parasitic helminths are ubiquitous in most host, including human, populations. Helminths
often alter the likelihood of infection and disease progression of coinfecting
microparasitic pathogens (viruses, bacteria, protozoa), and there is great interest in
incorporating deworming into control programmes for many major diseases (e.g. HIV,
tuberculosis, malaria). However, such calls are controversial; studies show the
consequences of deworming for the severity and spread of pathogens to be highly variable.
Hence, the benefits of deworming, although clear for reducing the morbidity due to
helminth infection per se, are unclear regarding the outcome of
coinfections and comorbidities. I develop a theoretical framework to explore how helminth
coinfection with other pathogens affects host mortality and pathogen spread and evolution
under different interspecific parasite interactions. In all cases the outcomes of
coinfection are highly context-dependent, depending on the mechanism of helminth-pathogen
interaction and the quantitative level of helminth infection, with the effects of
deworming potentially switching from beneficial to detrimental depending on helminth
burden. Such context-dependency may explain some of the variation in the benefits of
deworming seen between studies, and highlights the need for obtaining a quantitative
understanding of parasite interactions across realistic helminth infection ranges.
However, despite this complexity, this framework reveals predictable patterns in the
effects of helminths that may aid the development of more effective, integrated management
strategies to combat pathogens in this coinfected world.
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24
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Bishop SC. A consideration of resistance and tolerance for ruminant nematode infections. Front Genet 2012; 3:168. [PMID: 23248638 PMCID: PMC3522420 DOI: 10.3389/fgene.2012.00168] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 08/15/2012] [Indexed: 11/22/2022] Open
Abstract
Debates on the relative merits of resistance (the ability of the host to control the parasite lifecycle) and tolerance (the net impact of infection on host performance) are often lively and unhindered by data or evidence. Resistance generally shows continuous, heritable variation but data are sparser for tolerance, the utility of which will depend upon the disease prevalence. Prevalence is a function of group mean resistance and infection pressure, which itself is influenced by mean resistance. Tolerance will have most value for endemic diseases with a high prevalence but will be of little value for low prevalence diseases. The conditionality of tolerance on infection status, and hence resistance, makes it difficult to estimate independently of resistance. Tolerance is potentially tractable for nematode infections, as the prevalence of infection is ca. 100% in animals grazing infected pasture, and infection level can be quantified by faecal egg count (FEC). Whilst individual animal phenotypes for tolerance are difficult to estimate, breeding values are estimable if related animals graze pastures of different contamination levels. Selection for resistance, i.e., FEC, provides both direct and indirect benefits from ever decreased pasture contamination and hence decreased infectious challenge. Modeling and experimental studies have shown that such reductions in pasture contamination may lead to substantially increased performance. It is proposed that selection goals addressing nematode infections should include both resistance and performance under challenging conditions. However, there may be benefits from exploiting large datasets in which sires are used across cohorts differing in infection level, to further explore tolerance. This may help to customise breeding objectives, with tolerance given greater weight in heavily parasitized environments.
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Affiliation(s)
- Stephen C Bishop
- Genetics and Genomics, Royal (Dick) School of Veterinary Studies, The Roslin Institute, University of Edinburgh Edinburgh, UK
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25
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Glass EJ. The molecular pathways underlying host resistance and tolerance to pathogens. Front Genet 2012; 3:263. [PMID: 23403960 PMCID: PMC3566117 DOI: 10.3389/fgene.2012.00263] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/05/2012] [Indexed: 01/31/2023] Open
Abstract
Breeding livestock that are better able to withstand the onslaught of endemic- and exotic pathogens is high on the wish list of breeders and farmers world-wide. However, the defense systems in both pathogens and their hosts are complex and the degree of genetic variation in resistance and tolerance will depend on the trade-offs that they impose on host fitness as well as their life-histories. The genes and pathways underpinning resistance and tolerance traits may be distinct or intertwined as the outcome of any infection is a result of a balance between collateral damage of host tissues and control of the invading pathogen. Genes and molecular pathways associated with resistance are mainly expressed in the mucosal tract and the innate immune system and control the very early events following pathogen invasion. Resistance genes encode receptors involved in uptake of pathogens, as well as pattern recognition receptors (PRR) such as the toll-like receptor family as well as molecules involved in strong and rapid inflammatory responses which lead to rapid pathogen clearance, yet do not lead to immunopathology. In contrast tolerance genes and pathways play a role in reducing immunopathology or enhancing the host's ability to protect against pathogen associated toxins. Candidate tolerance genes may include cytosolic PRRs and unidentified sensors of pathogen growth, perturbation of host metabolism and intrinsic danger or damage associated molecules. In addition, genes controlling regulatory pathways, tissue repair and resolution are also tolerance candidates. The identities of distinct genetic loci for resistance and tolerance to infectious pathogens in livestock species remain to be determined. A better understanding of the mechanisms involved and phenotypes associated with resistance and tolerance should ultimately help to improve livestock health and welfare.
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Affiliation(s)
- Elizabeth J Glass
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh Edinburgh, UK
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Abstract
Invading infectious diseases can, in theory, lead to the extinction of host populations, particularly if reservoir species are present or if disease transmission is frequency-dependent. The number of historic or prehistoric extinctions that can unequivocally be attributed to infectious disease is relatively small, but gathering firm evidence in retrospect is extremely difficult. Amphibian chytridiomycosis and Tasmanian devil facial tumour disease (DFTD) are two very different infectious diseases that are currently threatening to cause extinctions in Australia. These provide an unusual opportunity to investigate the processes of disease-induced extinction and possible management strategies. Both diseases are apparently recent in origin. Tasmanian DFTD is entirely host-specific but potentially able to cause extinction because transmission depends weakly, if at all, on host density. Amphibian chytridiomycosis has a broad host range but is highly pathogenic only to some populations of some species. At present, both diseases can only be managed by attempting to isolate individuals or populations from disease. Management options to accelerate the process of evolution of host resistance or tolerance are being investigated in both cases. Anthropogenic changes including movement of diseases and hosts, habitat destruction and fragmentation and climate change are likely to increase emerging disease threats to biodiversity and it is critical to further develop strategies to manage these threats.
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Affiliation(s)
- Hamish McCallum
- Griffith School of Environment, Griffith University, Brisbane 4111, Australia.
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27
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Casadevall A, Fang FC, Pirofski LA. Microbial virulence as an emergent property: consequences and opportunities. PLoS Pathog 2011; 7:e1002136. [PMID: 21814511 PMCID: PMC3141035 DOI: 10.1371/journal.ppat.1002136] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Arturo Casadevall
- Department of Microbiology & Immunology and Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America.
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