1
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Hernandez CA, Delesalle VA, Krukonis GP, DeCurzio JM, Koskella B. Genomic and phenotypic signatures of bacteriophage coevolution with the phytopathogen Pseudomonas syringae. Mol Ecol 2024; 33:e16850. [PMID: 36651263 DOI: 10.1111/mec.16850] [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: 08/22/2022] [Revised: 11/21/2022] [Accepted: 12/06/2022] [Indexed: 01/19/2023]
Abstract
The rate and trajectory of evolution in an obligate parasite is critically dependent on those of its host(s). Adaptation to a genetically homogeneous host population should theoretically result in specialization, while adaptation to an evolving host population (i.e., coevolution) can result in various outcomes including diversification, range expansion, and/or local adaptation. For viruses of bacteria (bacteriophages, or phages), our understanding of how evolutionary history of the bacterial host(s) impacts viral genotypic and phenotypic evolution is currently limited. In this study, we used whole genome sequencing and two different metrics of phage impacts to compare the genotypes and phenotypes of lytic phages that had either coevolved with or were repeatedly passaged on an unchanging (ancestral) strain of the phytopathogen Pseudomonas syringae. Genomes of coevolved phages had more mutations than those of phages passaged on a constant host, and most mutations were in genes encoding phage tail-associated proteins. Phages from both passaging treatments shared some phenotypic outcomes, including range expansion and divergence across replicate populations, but coevolved phages were more efficient at reducing population growth (particularly of sympatric coevolved hosts). Genotypic similarity correlated with infectivity profile similarity in coevolved phages, but not in phages passaged on the ancestral host. Overall, while adaptation to either host type (coevolving or ancestral) led to divergence in phage tail proteins and infectivity patterns, coevolution led to more rapid molecular changes that increased bacterial killing efficiency and had more predictable effects on infectivity range. Together, these results underscore the important role of hosts in driving viral evolution and in shaping the genotype-phenotype relationship.
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Affiliation(s)
- Catherine A Hernandez
- Department of Integrative Biology, University of California, Berkeley, California, Berkeley, USA
| | | | - Greg P Krukonis
- Department of Biology, Angelo State University, San Angelo, Texas, USA
| | - Jenna M DeCurzio
- Department of Biology, Gettysburg College, Gettysburg, Pennsylvania, USA
| | - Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, California, Berkeley, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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2
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Mansueto G, Fusco G, Colonna G. A Tiny Viral Protein, SARS-CoV-2-ORF7b: Functional Molecular Mechanisms. Biomolecules 2024; 14:541. [PMID: 38785948 PMCID: PMC11118181 DOI: 10.3390/biom14050541] [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: 02/26/2024] [Revised: 04/01/2024] [Accepted: 04/17/2024] [Indexed: 05/25/2024] Open
Abstract
This study presents the interaction with the human host metabolism of SARS-CoV-2 ORF7b protein (43 aa), using a protein-protein interaction network analysis. After pruning, we selected from BioGRID the 51 most significant proteins among 2753 proven interactions and 1708 interactors specific to ORF7b. We used these proteins as functional seeds, and we obtained a significant network of 551 nodes via STRING. We performed topological analysis and calculated topological distributions by Cytoscape. By following a hub-and-spoke network architectural model, we were able to identify seven proteins that ranked high as hubs and an additional seven as bottlenecks. Through this interaction model, we identified significant GO-processes (5057 terms in 15 categories) induced in human metabolism by ORF7b. We discovered high statistical significance processes of dysregulated molecular cell mechanisms caused by acting ORF7b. We detected disease-related human proteins and their involvement in metabolic roles, how they relate in a distorted way to signaling and/or functional systems, in particular intra- and inter-cellular signaling systems, and the molecular mechanisms that supervise programmed cell death, with mechanisms similar to that of cancer metastasis diffusion. A cluster analysis showed 10 compact and significant functional clusters, where two of them overlap in a Giant Connected Component core of 206 total nodes. These two clusters contain most of the high-rank nodes. ORF7b acts through these two clusters, inducing most of the metabolic dysregulation. We conducted a co-regulation and transcriptional analysis by hub and bottleneck proteins. This analysis allowed us to define the transcription factors and miRNAs that control the high-ranking proteins and the dysregulated processes within the limits of the poor knowledge that these sectors still impose.
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Affiliation(s)
- Gelsomina Mansueto
- Dipartimento di Scienze Mediche e Chirurgiche Avanzate, Università della Campania, L. Vanvitelli, 80138 Naples, Italy;
| | - Giovanna Fusco
- Istituto Zooprofilattico Sperimentale del Mezzogiorno, 80055 Portici, Italy;
| | - Giovanni Colonna
- Medical Informatics AOU, Università della Campania, L. Vanvitelli, 80138 Naples, Italy
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3
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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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4
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Critchlow JT, Prakash A, Zhong KY, Tate AT. Mapping the functional form of the trade-off between infection resistance and reproductive fitness under dysregulated immune signaling. PLoS Pathog 2024; 20:e1012049. [PMID: 38408106 PMCID: PMC10919860 DOI: 10.1371/journal.ppat.1012049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 03/07/2024] [Accepted: 02/15/2024] [Indexed: 02/28/2024] Open
Abstract
Immune responses benefit organismal fitness by clearing parasites but also exact costs associated with immunopathology and energetic investment. Hosts manage these costs by tightly regulating the induction of immune signaling to curtail excessive responses and restore homeostasis. Despite the theoretical importance of turning off the immune response to mitigate these costs, experimentally connecting variation in the negative regulation of immune responses to organismal fitness remains a frontier in evolutionary immunology. In this study, we used a dose-response approach to manipulate the RNAi-mediated knockdown efficiency of cactus (IκBα), a central regulator of Toll pathway signal transduction in flour beetles (Tribolium castaneum). By titrating cactus activity across four distinct levels, we derived the shape of the relationship between immune response investment and traits associated with host fitness, including infection susceptibility, lifespan, fecundity, body mass, and gut homeostasis. Cactus knock-down increased the overall magnitude of inducible immune responses and delayed their resolution in a dsRNA dose-dependent manner, promoting survival and resistance following bacterial infection. However, these benefits were counterbalanced by dsRNA dose-dependent costs to lifespan, fecundity, body mass, and gut integrity. Our results allowed us to move beyond the qualitative identification of a trade-off between immune investment and fitness to actually derive its functional form. This approach paves the way to quantitatively compare the evolution and impact of distinct regulatory elements on life-history trade-offs and fitness, filling a crucial gap in our conceptual and theoretical models of immune signaling network evolution and the maintenance of natural variation in immune systems.
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Affiliation(s)
- Justin T Critchlow
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Arun Prakash
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Katherine Y Zhong
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ann T Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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5
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Soler JJ, Møller AP. Defensive tolerance to parasitism is correlated with sexual selection in swallows. Oecologia 2023; 203:267-276. [PMID: 37462738 PMCID: PMC10684419 DOI: 10.1007/s00442-023-05419-5] [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: 12/19/2022] [Accepted: 07/07/2023] [Indexed: 11/18/2023]
Abstract
Parasite-mediated sexual selection has been the topic of extensive research and enthusiastic debate for more than three decades. Here, we suggest that secondary sexual characters may not only signal parasite resistance but also defensive tolerance. We exemplify this possibility by analysing information on two sexually selected traits, annual reproductive success, and ectoparasitism in a barn swallow Hirundo rustica population followed for more than 30 years. For each individual, we estimated the slope of the association between reproductive success and parasitism as an index of tolerance and subsequently explored the association with the expression of the sexually selected traits. In accordance with expectations of parasites playing a role in sexual selection, tail length was negatively related to load of chewing lice and nest size was positively related to tolerance to chewing lice. We discuss the importance of considering defensive tolerance for understanding the role of parasite-mediated sexual selection.
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Affiliation(s)
- Juan José Soler
- Depto. Ecología Funcional Y Evolutiva, Estación Experimental de Zonas Áridas, Sacramento S/N, La Cañada de San Urbano, 04120, Almería, Spain.
| | - Anders Pape Møller
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, Orsay, France
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6
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Brook CE, Rozins C, Guth S, Boots M. Reservoir host immunology and life history shape virulence evolution in zoonotic viruses. PLoS Biol 2023; 21:e3002268. [PMID: 37676899 PMCID: PMC10484437 DOI: 10.1371/journal.pbio.3002268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 07/21/2023] [Indexed: 09/09/2023] Open
Abstract
The management of future pandemic risk requires a better understanding of the mechanisms that determine the virulence of emerging zoonotic viruses. Meta-analyses suggest that the virulence of emerging zoonoses is correlated with but not completely predictable from reservoir host phylogeny, indicating that specific characteristics of reservoir host immunology and life history may drive the evolution of viral traits responsible for cross-species virulence. In particular, bats host viruses that cause higher case fatality rates upon spillover to humans than those derived from any other mammal, a phenomenon that cannot be explained by phylogenetic distance alone. In order to disentangle the fundamental drivers of these patterns, we develop a nested modeling framework that highlights mechanisms that underpin the evolution of viral traits in reservoir hosts that cause virulence following cross-species emergence. We apply this framework to generate virulence predictions for viral zoonoses derived from diverse mammalian reservoirs, recapturing trends in virus-induced human mortality rates reported in the literature. Notably, our work offers a mechanistic hypothesis to explain the extreme virulence of bat-borne zoonoses and, more generally, demonstrates how key differences in reservoir host longevity, viral tolerance, and constitutive immunity impact the evolution of viral traits that cause virulence following spillover to humans. Our theoretical framework offers a series of testable questions and predictions designed to stimulate future work comparing cross-species virulence evolution in zoonotic viruses derived from diverse mammalian hosts.
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Affiliation(s)
- Cara E. Brook
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
| | - Carly Rozins
- Department of Science, Technology, and Society, York University, Toronto, Canada
| | - Sarah Guth
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Mike Boots
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, United States of America
- Biosciences, University of Exeter, Penryn, United Kingdom
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7
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Critchlow JT, Prakash A, Zhong KY, Tate AT. Mapping the functional form of the trade-off between infection resistance and reproductive fitness under dysregulated immune signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552815. [PMID: 37645726 PMCID: PMC10461925 DOI: 10.1101/2023.08.10.552815] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Immune responses benefit organismal fitness by clearing parasites but also exact costs associated with immunopathology and energetic investment. Hosts manage these costs by tightly regulating the induction of immune signaling to curtail excessive responses and restore homeostasis. Despite the theoretical importance of turning off the immune response to mitigate these costs, experimentally connecting variation in the negative regulation of immune responses to organismal fitness remains a frontier in evolutionary immunology. In this study, we used a dose-response approach to manipulate the RNAi-mediated knockdown efficiency of cactus (IκBα), a central regulator of Toll pathway signal transduction in flour beetles (Tribolium castaneum). By titrating cactus activity along a continuous gradient, we derived the shape of the relationship between immune response investment and traits associated with host fitness, including infection susceptibility, lifespan, fecundity, body mass, and gut homeostasis. Cactus knock-down increased the overall magintude of inducible immune responses and delayed their resolution in a dsRNA dose-dependent manner, promoting survival and resistance following bacterial infection. However, these benefits were counterbalanced by dsRNA dose-dependent costs to lifespan, fecundity, body mass, and gut integrity. Our results allowed us to move beyond the qualitative identification of a trade-off between immune investment and fitness to actually derive its functional form. This approach paves the way to quantitatively compare the evolution and impact of distinct regulatory elements on life-history trade-offs and fitness, filling a crucial gap in our conceptual and theoretical models of immune signaling network evolution and the maintenance of natural variation in immune systems.
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Affiliation(s)
- Justin T. Critchlow
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Arun Prakash
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Katherine Y. Zhong
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ann T. Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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8
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Kun Á, Hubai AG, Král A, Mokos J, Mikulecz BÁ, Radványi Á. Do pathogens always evolve to be less virulent? The virulence–transmission trade-off in light of the COVID-19 pandemic. Biol Futur 2023:10.1007/s42977-023-00159-2. [PMID: 37002448 PMCID: PMC10066022 DOI: 10.1007/s42977-023-00159-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/09/2023] [Indexed: 04/03/2023]
Abstract
AbstractThe direction the evolution of virulence takes in connection with any pathogen is a long-standing question. Formerly, it was theorized that pathogens should always evolve to be less virulent. As observations were not in line with this theoretical outcome, new theories emerged, chief among them the transmission–virulence trade-off hypotheses, which predicts an intermediate level of virulence as the endpoint of evolution. At the moment, we are very much interested in the future evolution of COVID-19’s virulence. Here, we show that the disease does not fulfill all the assumptions of the hypothesis. In the case of COVID-19, a higher viral load does not mean a higher risk of death; immunity is not long-lasting; other hosts can act as reservoirs for the virus; and death as a consequence of viral infection does not shorten the infectious period. Consequently, we cannot predict the short- or long-term evolution of the virulence of COVID-19.
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9
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Best A, Ashby B. How do fluctuating ecological dynamics impact the evolution of hosts and parasites? Philos Trans R Soc Lond B Biol Sci 2023; 378:20220006. [PMID: 36744565 PMCID: PMC9900711 DOI: 10.1098/rstb.2022.0006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Theoretical models of the evolution of parasites and their hosts have shaped our understanding of infectious disease dynamics for over 40 years. Many theoretical models assume that the underlying ecological dynamics are at equilibrium or constant, yet we know that in a great many systems there are fluctuations in the ecological dynamics owing to a variety of intrinsic or extrinsic factors. Here, we discuss the challenges presented when modelling evolution in systems with fluctuating ecological dynamics and summarize the main approaches that have been developed to study host-parasite evolution in such systems. We provide an in-depth guide to one of the methods by applying it to two worked examples of host evolution that have not previously been studied in the literature: when cycles occur owing to seasonal forcing in competition, and when the presence of a free-living parasite causes cycles, with accompanying interactive Python code provided. We review the findings of studies that have explored host-parasite evolution when ecological dynamics fluctuate, and point to areas of future research. Throughout we stress the importance of feedbacks between the ecological and evolutionary dynamics in driving the outcomes of infectious disease systems. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- A. Best
- School of Mathematics and Statistics, University of Sheffield, Sheffield S3 7RH, UK,Integrative Biology, University of California - Berkeley, Berkeley, CA 94720-5800, USA
| | - B. Ashby
- Department of Mathematics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6,Department of Mathematics, University of Bath, Bath BA2 7AY, UK
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10
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Kutzer MAM, Gupta V, Neophytou K, Doublet V, Monteith KM, Vale PF. Intraspecific genetic variation in host vigour, viral load and disease tolerance during Drosophila C virus infection. Open Biol 2023; 13:230025. [PMID: 36854375 PMCID: PMC9974301 DOI: 10.1098/rsob.230025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
Genetic variation for resistance and disease tolerance has been described in a range of species. In Drosophila melanogaster, genetic variation in mortality following systemic Drosophila C virus (DCV) infection is driven by large-effect polymorphisms in the restriction factor pastrel (pst). However, it is unclear if pst contributes to disease tolerance. We investigated systemic DCV challenges spanning nine orders of magnitude, in males and females of 10 Drosophila Genetic Reference Panel lines carrying either a susceptible (S) or resistant (R) pst allele. We find among-line variation in fly survival, viral load and disease tolerance measured both as the ability to maintain survival (mortality tolerance) and reproduction (fecundity tolerance). We further uncover novel effects of pst on host vigour, as flies carrying the R allele exhibited higher survival and fecundity even in the absence of infection. Finally, we found significant genetic variation in the expression of the JAK-STAT ligand upd3 and the epigenetic regulator of JAK-STAT G9a. However, while G9a has been previously shown to mediate tolerance of DCV infection, we found no correlation between the expression of either upd3 or G9a on fly tolerance or resistance. Our work highlights the importance of both resistance and tolerance in viral defence.
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Affiliation(s)
- Megan A. M. Kutzer
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Vanika Gupta
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Kyriaki Neophytou
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, UK
| | - Vincent Doublet
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Katy M. Monteith
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Pedro F. Vale
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
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11
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McDonald CA, Becker CG, Lambertini C, Toledo LF, Haddad CFB, Zamudio KR. Host immune responses to enzootic and invasive pathogen lineages vary in magnitude, timing, and efficacy. Mol Ecol 2023; 32:2252-2270. [PMID: 36799008 DOI: 10.1111/mec.16890] [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: 08/12/2022] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023]
Abstract
Infectious diseases of wildlife continue to pose a threat to biodiversity worldwide, yet pathogens are far from uniform in virulence or host disease outcome. Within the same pathogen species, virulence can vary considerably depending on strain or lineage, in turn eliciting variable host responses. One pathogen that has caused extensive biodiversity loss is the amphibian-killing fungus, Batrachochytrium dendrobatidis (Bd), which is comprised of a globally widespread hypervirulent lineage (Bd-GPL), and multiple geographically restricted, enzootic lineages. Whereas host immunogenomic responses to Bd-GPL have been characterized in a number of amphibian species, immunogenomic responses to geographically restricted, enzootic Bd lineages are less clear. To examine lineage-specific host immune responses to Bd, we exposed a species of pumpkin toadlet, Brachycephalus pitanga, which is endemic to Brazil's Southern Atlantic Forest, to either the Bd-GPL or the enzootic Bd-Asia-2/Brazil (hereafter Bd-Brazil) lineage. Using temporal samples from early, mid, and late infection stages, we quantified functional immunogenomic responses over the course of infection using differential gene expression tests and coexpression network analyses. Host immune responses varied significantly with Bd lineage. Relative to controls, toadlet responses to Bd-Brazil were weak at early infection (25 genes significantly differentially expressed), peaked by mid-stage infection (414 genes), and were nearly fully resolved by late-stage infection (nine genes). In contrast, responses to Bd-GPL were magnified and delayed; toadlets significantly differentially expressed 111 genes early, 87 genes at mid-stage infection, and 726 genes by late-stage infection relative to controls. Given that infection intensity did not vary between mid- and late-stage disease in either Bd-Brazil or Bd-GPL treatments, this suggests that pumpkin toadlets may be at least partially tolerant to the enzootic Bd-Brazil lineage. In contrast, late-stage immune activation against Bd-GPL was consistent with immune dysregulation previously observed in other species. Our results demonstrate that both the timing of immune response and the particular immune pathways activated are specific to Bd lineage. Within regions where multiple Bd lineages co-occur, and given continued global Bd movement, these differential host responses may influence not only individual disease outcome, but transmission dynamics at the population and community levels.
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Affiliation(s)
- Coby A McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - C Guilherme Becker
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Carolina Lambertini
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia Unicamp, Campinas, São Paulo, Brazil
| | - L Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia Unicamp, Campinas, São Paulo, Brazil
| | - Célio F B Haddad
- Departamento de Biodiversidade e Centro de Aquicultura (CAUNESP), Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, Brazil
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA.,Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
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12
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A Sterility-Mortality Tolerance Trade-Off Leads to Within-Population Variation in Host Tolerance. Bull Math Biol 2023; 85:16. [PMID: 36670241 DOI: 10.1007/s11538-023-01119-6] [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: 11/05/2022] [Accepted: 01/02/2023] [Indexed: 01/21/2023]
Abstract
While experimental studies have demonstrated within-population variation in host tolerance to parasitism, theoretical studies rarely predict for polymorphism to arise. However, most theoretical models do not consider the crucial distinction between tolerance to the effects of infection-induced deaths (mortality tolerance) and tolerance to the parasite-induced reduction in the reproduction of infected hosts (sterility tolerance). While some studies have examined trade-offs between host tolerance and resistance mechanisms, none has considered a correlation within different tolerance mechanisms. We assume that sterility tolerance and mortality tolerance are directly traded-off in a host population subjected to a pathogen and use adaptive dynamics to study their evolutionary behaviour. We find that such a trade-off between the two tolerance strategies can drive the host population to branch into dimorphic strains, leading to coexistence of strains with sterile hosts that have low mortality and fully fertile with high mortality rates. Further, we find that a wider range of trade-off shapes allows branching at intermediate- or high-infected population size. Our other significant finding is that sterility tolerance is maximised (and mortality tolerance minimised) at an intermediate disease-induced mortality rate. Additionally, evolution entirely reverses the disease prevalence pattern corresponding to the recovery rate, compared to when no strategies evolve. We provide novel predictions on the evolutionary behaviour of two tolerance strategies concerning such a trade-off.
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13
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Weber JN, Steinel NC, Peng F, Shim KC, Lohman BK, Fuess LE, Subramanian S, Lisle SPD, Bolnick DI. Evolutionary gain and loss of a pathological immune response to parasitism. Science 2022; 377:1206-1211. [PMID: 36074841 PMCID: PMC9869647 DOI: 10.1126/science.abo3411] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Parasites impose fitness costs on their hosts. Biologists often assume that natural selection favors infection-resistant hosts. Yet, when the immune response itself is costly, theory suggests that selection may sometimes favor loss of resistance, which may result in alternative stable states where some populations are resistant and others are tolerant. Intraspecific variation in immune costs is rarely surveyed in a manner that tests evolutionary patterns, and there are few examples of adaptive loss of resistance. Here, we show that when marine threespine stickleback colonized freshwater lakes, they gained resistance to the freshwater-associated cestode Schistocephalus solidus. Extensive peritoneal fibrosis and inflammation are a commonly observed phenotype that contributes to suppression of cestode growth and viability but also imposes a substantial cost on fecundity. Combining genetic mapping and population genomics, we find that opposing selection generates immune system differences between tolerant and resistant populations, consistent with divergent optimization.
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Affiliation(s)
- Jesse N Weber
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Natalie C Steinel
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Foen Peng
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Kum Chuan Shim
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Brian K Lohman
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Lauren E Fuess
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Swapna Subramanian
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Stephen P De Lisle
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Daniel I Bolnick
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.,Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
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14
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Armitage SA, Genersch E, McMahon DP, Rafaluk-Mohr C, Rolff J. Tripartite interactions: how immunity, microbiota and pathogens interact and affect pathogen virulence evolution. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100871. [PMID: 34999035 DOI: 10.1016/j.cois.2021.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
The bipartite interactions between insect hosts and their bacterial gut microbiota, or their bacterial pathogens, are empirically and theoretically well-explored. However, direct, and indirect tripartite interactions will also likely occur inside a host. These interactions will almost certainly affect the trajectory of pathogen virulence evolution, an area that is currently under researched. The interactions within tripartite associations can be competitive, that is, exploitative-competition, interference-competition or apparent-competition. Competitive interactions will be significantly influenced by non-competitive effects, for example, immunopathology, immunosuppression, and microbiota-mediated tolerance. Considering a combination of these interactions and effects, will enable an increased understanding of the evolution of pathogen virulence. This new perspective allows us to identify several novel research questions, which we hope will be a useful framework for future research.
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Affiliation(s)
- Sophie Ao Armitage
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany.
| | - Elke Genersch
- Institute for Bee Research, Friedrich-Engels-Straße 32, 16540 Hohen Neuendorf, Germany; Institute of Microbiology and Epizootics, Faculty of Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Straße 7-13, 14163 Berlin, Germany
| | - Dino P McMahon
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany; Department for Materials and Environment, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin, Germany
| | - Charlotte Rafaluk-Mohr
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany
| | - Jens Rolff
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
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15
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Rafaluk-Mohr C, Gerth M, Sealey JE, Ekroth AKE, Aboobaker AA, Kloock A, King KC. Microbial protection favors parasite tolerance and alters host-parasite coevolutionary dynamics. Curr Biol 2022; 32:1593-1598.e3. [PMID: 35148861 PMCID: PMC9355892 DOI: 10.1016/j.cub.2022.01.063] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 10/14/2021] [Accepted: 01/21/2022] [Indexed: 12/05/2022]
Abstract
Coevolution between hosts and parasites is a major driver of rapid evolutionary change1 and diversification.2,3 However, direct antagonistic interactions between hosts and parasites could be disrupted4 when host microbiota form a line of defense, a phenomenon widespread across animal and plant species.5,6 By suppressing parasite infection, protective microbiota could reduce the need for host-based defenses and favor host support for microbiota colonization,6 raising the possibility that the microbiota can alter host-parasite coevolutionary patterns and processes.7 Here, using an experimental evolution approach, we co-passaged populations of nematode host (Caenorhabditis elegans) and parasites (Staphylococcus aureus) when hosts were colonized (or not) by protective bacteria (Enterococcus faecalis). We found that microbial protection during coevolution resulted in the evolution of host mortality tolerance—higher survival following parasite infection—and in parasites adapting to microbial defenses. Compared to unprotected host-parasite coevolution, the protected treatment was associated with reduced dominance of fluctuating selection dynamics in host populations. No differences in host recombination rate or genetic diversity were detected. Genomic divergence was observed between parasite populations coevolved in protected and unprotected hosts. These findings indicate that protective host microbiota can determine the evolution of host defense strategies and shape host-parasite coevolutionary dynamics. Microbial protection resulted in the evolution of host mortality tolerance Parasites adapted to counter microbial defenses within hosts Protective microbes reduced fluctuating selection dynamics Microbial protection did not impact host genetic diversity or recombination rates
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Affiliation(s)
| | - Michael Gerth
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford OX3 0BP, UK
| | - Jordan E Sealey
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Alice K E Ekroth
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Aziz A Aboobaker
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Anke Kloock
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Kayla C King
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK.
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16
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Shukla A, Pagán I, Crevillén P, Alonso‐Blanco C, García‐Arenal F. A role of flowering genes in the tolerance of Arabidopsis thaliana to cucumber mosaic virus. MOLECULAR PLANT PATHOLOGY 2022; 23:175-187. [PMID: 34672409 PMCID: PMC8743021 DOI: 10.1111/mpp.13151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
The genetic basis of plant tolerance to parasites is poorly understood. We have previously shown that tolerance of Arabidopsis thaliana to its pathogen cucumber mosaic virus is achieved through changes in host life-history traits on infection that result in delaying flowering and reallocating resources from vegetative growth to reproduction. In this system we analyse here genetic determinants of tolerance using a recombinant inbred line family derived from a cross of two accessions with extreme phenotypes. Three major quantitative trait loci for tolerance were identified, which co-located with three flowering repressor genes, FLC, FRI, and HUA2. The role of these genes in tolerance was further examined in genotypes carrying functional or nonfunctional alleles. Functional alleles of FLC together with FRI and/or HUA2 were required for both tolerance and resource reallocation from growth to reproduction. Analyses of FLC alleles from wild accessions that differentially modulate flowering time showed that they ranked differently for their effects on tolerance and flowering. These results pinpoint a role of FLC in A. thaliana tolerance to cucmber mosaic virus, which is a novel major finding, as FLC has not been recognized previously to be involved in plant defence. Although tolerance is associated with a delay in flowering that allows resource reallocation, our results indicate that FLC regulates tolerance and flowering initiation by different mechanisms. Thus, we open a new avenue of research on the interplay between defence and development in plants.
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Affiliation(s)
- Aayushi Shukla
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y AlimentariaMadridSpain
- Present address:
Department of Plant BiologyUppsala BioCenterSwedish University of Agricultural Sciences75007UppsalaSweden
| | - Israel Pagán
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y AlimentariaMadridSpain
- ETSI Agronómica, Alimentaria y de BiosistemasMadridSpain
| | - Pedro Crevillén
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y AlimentariaMadridSpain
| | - Carlos Alonso‐Blanco
- Departamento de Genética Molecular de PlantasCentro Nacional de BiotecnologíaConsejo Superior de Investigaciones CientíficasMadridSpain
| | - Fernando García‐Arenal
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y AlimentariaMadridSpain
- ETSI Agronómica, Alimentaria y de BiosistemasMadridSpain
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17
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Buckingham LJ, Ashby B. Coevolutionary theory of hosts and parasites. J Evol Biol 2022; 35:205-224. [PMID: 35030276 PMCID: PMC9305583 DOI: 10.1111/jeb.13981] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/14/2021] [Accepted: 01/05/2022] [Indexed: 11/30/2022]
Abstract
Host and parasite evolution are closely intertwined, with selection for adaptations and counter‐adaptations forming a coevolutionary feedback loop. Coevolutionary dynamics are often difficult to intuit due to these feedbacks and are hard to demonstrate empirically in most systems. Theoretical models have therefore played a crucial role in shaping our understanding of host–parasite coevolution. Theoretical models vary widely in their assumptions, approaches and aims, and such variety makes it difficult, especially for non‐theoreticians and those new to the field, to: (1) understand how model approaches relate to one another; (2) identify key modelling assumptions; (3) determine how model assumptions relate to biological systems; and (4) reconcile the results of different models with contrasting assumptions. In this review, we identify important model features, highlight key results and predictions and describe how these pertain to model assumptions. We carry out a literature survey of theoretical studies published since the 1950s (n = 219 papers) to support our analysis. We identify two particularly important features of models that tend to have a significant qualitative impact on the outcome of host–parasite coevolution: population dynamics and the genetic basis of infection. We also highlight the importance of other modelling features, such as stochasticity and whether time proceeds continuously or in discrete steps, that have received less attention but can drastically alter coevolutionary dynamics. We finish by summarizing recent developments in the field, specifically the trend towards greater model complexity, and discuss likely future directions for research.
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Affiliation(s)
- Lydia J Buckingham
- Department of Mathematical Sciences, University of Bath, Bath, UK, BA2 7AY.,Milner Centre for Evolution, University of Bath, Bath, UK, BA2 7AY
| | - Ben Ashby
- Department of Mathematical Sciences, University of Bath, Bath, UK, BA2 7AY.,Milner Centre for Evolution, University of Bath, Bath, UK, BA2 7AY
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18
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Abstract
AbstractTrade-offs and constraints are inherent to life, and studies of these phenomena play a central role in both organismal and evolutionary biology. Trade-offs can be defined, categorized, and studied in at least six, not mutually exclusive, ways. (1) Allocation constraints are caused by a limited resource (e.g., energy, time, space, essential nutrients), such that increasing allocation to one component necessarily requires a decrease in another (if only two components are involved, this is referred to as the Y-model, e.g., energy devoted to size versus number of offspring). (2) Functional conflicts occur when features that enhance performance of one task decrease performance of another (e.g., relative lengths of in-levers and out-levers, force-velocity trade-offs related to muscle fiber type composition). (3) Shared biochemical pathways, often involving integrator molecules (e.g., hormones, neurotransmitters, transcription factors), can simultaneously affect multiple traits, with some effects being beneficial for one or more components of Darwinian fitness (e.g., survival, age at first reproduction, fecundity) and others detrimental. (4) Antagonistic pleiotropy describes genetic variants that increase one component of fitness (or a lower-level trait) while simultaneously decreasing another. (5) Ecological circumstances (or selective regime) may impose trade-offs, such as when foraging behavior increases energy availability yet also decreases survival. (6) Sexual selection may lead to the elaboration of (usually male) secondary sexual characters that improve mating success but handicap survival and/or impose energetic costs that reduce other fitness components. Empirical studies of trade-offs often search for negative correlations between two traits that are the expected outcomes of the trade-offs, but this will generally be inadequate if more than two traits are involved and especially for complex physiological networks of interacting traits. Moreover, trade-offs often occur only in populations that are experiencing harsh environmental conditions or energetic challenges at the extremes of phenotypic distributions, such as among individuals or species that have exceptional athletic abilities. Trade-offs may be (partially) circumvented through various compensatory mechanisms, depending on the timescale involved, ranging from acute to evolutionary. Going forward, a pluralistic view of trade-offs and constraints, combined with integrative analyses that cross levels of biological organization and traditional boundaries among disciplines, will enhance the study of evolutionary organismal biology.
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19
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Drew GC, Stevens EJ, King KC. Microbial evolution and transitions along the parasite-mutualist continuum. Nat Rev Microbiol 2021; 19:623-638. [PMID: 33875863 PMCID: PMC8054256 DOI: 10.1038/s41579-021-00550-7] [Citation(s) in RCA: 105] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2021] [Indexed: 12/28/2022]
Abstract
Virtually all plants and animals, including humans, are home to symbiotic microorganisms. Symbiotic interactions can be neutral, harmful or have beneficial effects on the host organism. However, growing evidence suggests that microbial symbionts can evolve rapidly, resulting in drastic transitions along the parasite-mutualist continuum. In this Review, we integrate theoretical and empirical findings to discuss the mechanisms underpinning these evolutionary shifts, as well as the ecological drivers and why some host-microorganism interactions may be stuck at the end of the continuum. In addition to having biomedical consequences, understanding the dynamic life of microorganisms reveals how symbioses can shape an organism's biology and the entire community, particularly in a changing world.
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Affiliation(s)
| | | | - Kayla C King
- Department of Zoology, University of Oxford, Oxford, UK.
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20
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Piecyk A, Hahn MA, Roth O, Dheilly NM, Heins DC, Bell MA, Kalbe M. Cross-continental experimental infections reveal distinct defence mechanisms in populations of the three-spined stickleback Gasterosteus aculeatus. Proc Biol Sci 2021; 288:20211758. [PMID: 34547906 PMCID: PMC8456148 DOI: 10.1098/rspb.2021.1758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/02/2021] [Indexed: 11/12/2022] Open
Abstract
Epidemiological traits of host-parasite associations depend on the effects of the host, the parasite and their interaction. Parasites evolve mechanisms to infect and exploit their hosts, whereas hosts evolve mechanisms to prevent infection and limit detrimental effects. The reasons why and how these traits differ across populations still remain unclear. Using experimental cross-infection of three-spined stickleback Gasterosteus aculeatus and their species-specific cestode parasites Schistocephalus solidus from Alaskan and European populations, we disentangled host, parasite and interaction effects on epidemiological traits at different geographical scales. We hypothesized that host and parasite main effects would dominate both within and across continents, although interaction effects would show geographical variation of natural selection within and across continents. We found that mechanisms preventing infection (qualitative resistance) occurred only in a combination of hosts and parasites from different continents, while mechanisms limiting parasite burden (quantitative resistance) and reducing detrimental effects of infection (tolerance) were host-population specific. We conclude that evolution favours distinct defence mechanisms on different geographical scales and that it is important to distinguish concepts of qualitative resistance, quantitative resistance and tolerance in studies of macroparasite infections.
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Affiliation(s)
- Agnes Piecyk
- Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Megan A. Hahn
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Olivia Roth
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Marine Evolutionary Biology, Kiel University, Kiel, Germany
| | - Nolwenn M. Dheilly
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, USA
| | - David C. Heins
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| | - Michael A. Bell
- University of California Museum of Paleontology, University of California, Berkeley, CA, USA
| | - Martin Kalbe
- Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
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21
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The ecology of zoonotic parasites in the Carnivora. Trends Parasitol 2021; 37:1096-1110. [PMID: 34544647 DOI: 10.1016/j.pt.2021.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 01/08/2023]
Abstract
The order Carnivora includes over 300 species that vary many orders of magnitude in size and inhabit all major biomes, from tropical rainforests to polar seas. The high diversity of carnivore parasites represents a source of potential emerging diseases of humans. Zoonotic risk from this group may be driven in part by exceptionally high functional diversity of host species in behavioral, physiological, and ecological traits. We review global macroecological patterns of zoonotic parasites within carnivores, and explore the traits of species that serve as hosts of zoonotic parasites. We synthesize theoretical and empirical research and suggest future work on the roles of carnivores as biotic multipliers, regulators, and sentinels of zoonotic disease as timely research frontiers.
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22
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Montes N, Vijayan V, Pagán I. Host population structure for tolerance determines the evolution of plant-virus interactions. THE NEW PHYTOLOGIST 2021; 231:1570-1585. [PMID: 33997993 PMCID: PMC8362011 DOI: 10.1111/nph.17466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/02/2021] [Indexed: 06/12/2023]
Abstract
Heterogeneity for plant defences determines both the capacity of host populations to buffer the effect of infection and the pathogen´s fitness. However, little information is known on how host population structure for tolerance, a major plant defence, impacts the evolution of plant-pathogen interactions. By performing 10 serial passages of Turnip mosaic virus (TuMV) in Arabidopsis thaliana populations with varying proportion of tolerant genotypes simulating different structures for this trait, we analysed how host heterogeneity for this defence shapes the evolution of both virus multiplication, the effect of infection on plant fecundity and mortality, and plant tolerance and resistance. Results indicated that a higher proportion of tolerant genotypes in the host population promotes virus multiplication and reduces the effect of infection on plant mortality, but not on plant fecundity. These changes resulted in more effective plant tolerance to virus infection. Conversely, a lower proportion of tolerant genotypes reduced virus multiplication, boosting plant resistance. Our work for the first time provides evidence of the main role of host population structure for tolerance on pathogen evolution and on the subsequent feedback loops on plant defences.
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Affiliation(s)
- Nuria Montes
- Fisiología VegetalDepartamento Ciencias Farmacéuticas y de la SaludFacultad de FarmaciaUniversidad San Pablo‐CEU UniversitiesBoadilla del Monte (Madrid)28668Spain
- Servicio de ReumatologíaHospital Universitario de la PrincesaInstituto de Investigación Sanitaria (IIS‐IP)Madrid28008Spain
| | - Viji Vijayan
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA and ETS Ingeniería Agronómica, Alimentaria y de BiosistemasUniversidad Politécnica de MadridMadrid28223Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA and ETS Ingeniería Agronómica, Alimentaria y de BiosistemasUniversidad Politécnica de MadridMadrid28223Spain
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23
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Higher mortality of the less suitable brown trout host compared to the principal Atlantic salmon host when infested with freshwater pearl mussel (Margaritifera margaritifera) glochidia. Parasitol Res 2021; 120:2401-2413. [PMID: 33844065 PMCID: PMC8263406 DOI: 10.1007/s00436-021-07145-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 03/30/2021] [Indexed: 10/31/2022]
Abstract
The freshwater pearl mussel (Margaritifera margaritifera) is a highly host-specific parasite, with an obligate parasitic stage on salmonid fish. Atlantic salmon (Salmo salar) and brown trout (Salmo trutta f. trutta and Salmo trutta f. fario) are the only hosts in their European distribution. Some M. margaritifera populations exclusively infest either Atlantic salmon or brown trout, while others infest both hosts with one salmonid species typically being the principal host and the other a less suitable host. Glochidial abundance, prevalence and growth are often used as parameters to measure host suitability, with the most suitable host species displaying the highest parameters. However, it is not known if the degree of host specialisation will negatively influence host fitness (virulence) among different host species. In this study we examined the hypothesis that glochidial infestation would result in differential virulence in two salmonid host species and that lower virulence would be observed on the most suitable host. Atlantic salmon and brown trout were infested with glochidia from two M. margaritifera populations that use Atlantic salmon as their principal host, and the difference in host mortality among infested and control (sham infested) fish was examined. Higher mortality was observed in infested brown trout (the less suitable host) groups, compared to the other test groups. Genetic assignment was used to identify offspring from individual mother mussels. We found that glochidia from individual mothers can infest both the salmonid hosts; however, some mothers displayed a bias towards either salmon or trout. We believe that the differences in host-dependent virulence and the host bias displayed by individual mothers were a result of genotype × genotype interactions between the glochidia and their hosts, indicating that there is an underlying genetic component for this parasite-host interaction.
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24
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Manzoli DE, Saravia-Pietropaolo MJ, Arce SI, Percara A, Antoniazzi LR, Beldomenico PM. Specialist by preference, generalist by need: availability of quality hosts drives parasite choice in a natural multihost-parasite system. Int J Parasitol 2021; 51:527-534. [PMID: 33713648 DOI: 10.1016/j.ijpara.2020.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 11/24/2022]
Abstract
Encountering suitable hosts is key for parasite success. A general assumption for disease transmission is that the contact of a parasite with a potential host is driven by the density or relative frequency of hosts. That assumption ignores the potential role of differential host attractiveness for parasites that can drive the encounter of hosts. It has been posited that hosts may be chosen by parasites as a function of their suitability, but the existing literature addressing that hypothesis is still very scarce. In a natural system involving a parasitic Philornis botfly and its multiple bird hosts, there are profound differences in host quality. The Great Kiskadee tolerates and does not invest in resisting the infection, which makes it an optimal host. Alternative hosts are frequently used, but whilst some of them may be good options, others are bad alternatives. Here we examined the host selection processes that drive parasite dynamics in this system with 8 years of data from a longitudinal study under natural conditions. We found that the use of an alternative host was not driven by its density or relative frequency, but instead selection of these hosts was strongly dependent on availability of more suitable hosts. When optimal hosts are plentiful, the parasite tends to ignore alternative ones. As broods of optimal hosts become limited, good alternative hosts are targeted. The parasite chooses bad alternative hosts only when better alternatives are not sufficiently available. These results add evidence from a natural system that some parasites choose their hosts as a function of their profitability, and show that host selection by this parasite is plastic and context-dependent. Such findings could have important implications for the epidemiology of some parasitic and vector-borne infections which should be considered when modelling and managing those diseases. The facultative host selection observed here can be of high relevance for public health, animal husbandry, and biodiversity conservation, because reductions in the richness of hosts might cause humans, domestic animals, or endangered species to become increasingly targeted by parasites that can drive the encounter of hosts.
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Affiliation(s)
- Darío Ezequiel Manzoli
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina
| | - María José Saravia-Pietropaolo
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Sofía Irene Arce
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Alejandro Percara
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Leandro Raúl Antoniazzi
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina
| | - Pablo Martín Beldomenico
- Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas), Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional del Litoral, RP Kreder 2805, 3080 Esperanza, Santa Fe, Argentina.
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25
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Borghi M, Puccetti M, Pariano M, Renga G, Stincardini C, Ricci M, Giovagnoli S, Costantini C, Romani L. Tryptophan as a Central Hub for Host/Microbial Symbiosis. Int J Tryptophan Res 2020; 13:1178646920919755. [PMID: 32435131 PMCID: PMC7225782 DOI: 10.1177/1178646920919755] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 03/14/2020] [Indexed: 01/06/2023] Open
Abstract
Amino acid catabolism occurs during inflammation and regulates innate and adaptive immunity. The role of commensal bacteria in amino acid catabolism and the production of metabolites able to regulate the development and function of the innate immune system is increasingly being recognized. Therefore, commensal bacteria are key players in the maintenance of immune homeostasis. However, the intestinal microbiota also contributes to susceptibility and response to infectious diseases. This is self-evident for fungal infections known to occur as a consequence of weakened immune system and broad-spectrum antibiotic use or abuse. Thus, diseases caused by opportunistic fungi can no longer be viewed as dependent only on a weakened host but also on a disrupted microbiota. Based on these premises, the present review focuses on the role of amino acid metabolic pathways in the dialogue between the mammalian host and its microbiota and the potential implications in fungal commensalism and infectivity.
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Affiliation(s)
- Monica Borghi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Matteo Puccetti
- Department of Pharmaceutical Science, University of Perugia, Perugia, Italy
| | - Marilena Pariano
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Giorgia Renga
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | | | - Maurizio Ricci
- Department of Pharmaceutical Science, University of Perugia, Perugia, Italy
| | - Stefano Giovagnoli
- Department of Pharmaceutical Science, University of Perugia, Perugia, Italy
| | - Claudio Costantini
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Luigina Romani
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
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26
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Wollein Waldetoft K, Råberg L, Lood R. Proliferation and benevolence-A framework for dissecting the mechanisms of microbial virulence and health promotion. Evol Appl 2020; 13:879-888. [PMID: 32431740 PMCID: PMC7232753 DOI: 10.1111/eva.12952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 01/14/2020] [Accepted: 03/06/2020] [Indexed: 12/29/2022] Open
Abstract
Key topics in the study of host–microbe interactions—such as the prevention of drug resistance and the exploitation of beneficial effects of bacteria—would benefit from concerted efforts with both mechanistic and evolutionary approaches. But due to differences in intellectual traditions, insights gained in one field rarely benefit the other. Here, we develop a conceptual and analytical framework for the integrated study of host–microbe interactions. This framework partitions the health effects of microbes and the effector molecules they produce into components with different evolutionary implications. It thereby facilitates the prediction of evolutionary responses to inhibition and exploitation of specific molecular mechanisms.
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Affiliation(s)
| | - Lars Råberg
- Department of Biology Lund University Lund Sweden
| | - Rolf Lood
- Division of Infection Medicine Department of Clinical Sciences Lund University Lund Sweden
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Henschen AE, Adelman JS. What Does Tolerance Mean for Animal Disease Dynamics When Pathology Enhances Transmission? Integr Comp Biol 2020; 59:1220-1230. [PMID: 31141137 DOI: 10.1093/icb/icz065] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Host competence, or how well an individual transmits pathogens, varies substantially within and among animal populations. As this variation can alter the course of epidemics and epizootics, revealing its underlying causes will help predict and control the spread of disease. One host trait that could drive heterogeneity in competence is host tolerance, which minimizes fitness losses during infection without decreasing pathogen load. In many cases, tolerance should increase competence by extending infectious periods and enabling behaviors that facilitate contact among hosts. However, we argue that the links between tolerance and competence are more varied. Specifically, the different physiological and behavioral mechanisms by which hosts achieve tolerance should have a range of effects on competence, enhancing the ability to transmit pathogens in some circumstances and impeding it in others. Because tissue-based pathology (damage) that reduces host fitness is often critical for pathogen transmission, we focus on two mechanisms that can underlie tolerance at the tissue level: damage-avoidance and damage-repair. As damage-avoidance reduces transmission-enhancing pathology, this mechanism is likely to decrease host competence and pathogen transmission. In contrast, damage-repair does not prevent transmission-relevant pathology from occurring. Rather, damage-repair provides new, healthy tissues that pathogens can exploit, likely extending the infectious period and increasing host competence. We explore these concepts through graphical models and present three disease systems in which damage-avoidance and damage-repair alter host competence in the predicted directions. Finally, we suggest that by incorporating these links, future theoretical studies could provide new insights into infectious disease dynamics and host-pathogen coevolution.
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Affiliation(s)
- Amberleigh E Henschen
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, 2310 Pammel Drive, Ames, IA 50011, USA
| | - James S Adelman
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, 2310 Pammel Drive, Ames, IA 50011, USA
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Ferris C, Best A. The effect of temporal fluctuations on the evolution of host tolerance to parasitism. Theor Popul Biol 2019; 130:182-190. [PMID: 31415775 DOI: 10.1016/j.tpb.2019.07.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 05/29/2019] [Accepted: 07/29/2019] [Indexed: 11/19/2022]
Abstract
There are many mechanisms that hosts can evolve to defend against parasites, two of which are resistance and tolerance. These defences often have different evolutionary behaviours, and it is important to consider how each individual mechanism may respond to changes in environment. In particular, host defence through tolerance is predicted to be unlikely to lead to variation, despite many observations of diversity in both animal and plant systems. Hence understanding the drivers of diversity in host defence and parasite virulence is vital for predicting future evolutionary changes in infectious disease dynamics. It has been suggested that heterogeneous environments might generally promote diversity, but the effect of temporal fluctuations has received little attention theoretically or empirically, and there has been no examination of how temporal fluctuations affects the evolution of host tolerance. In this study, we use a mathematical model to investigate the evolution of host tolerance in a temporally fluctuating environment. We show that investment in tolerance increases in more variable environments, giving qualitatively different evolutionary behaviours when compared to resistance. Once seasonality is introduced evolutionary branching though tolerance can occur and create diversity within the population, although potentially only temporarily. This branching behaviour arises due to the emergence of a negative feedback with the maximum infected density on a cycle, which is strongest when the infected population is large. This work reinforces the qualitative differences between tolerance and resistance evolution, but also provides theoretical evidence for the theory that heterogeneous environments promote host-parasite diversity, hence constant environment assumptions may omit important evolutionary outcomes.
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Affiliation(s)
- Charlotte Ferris
- School of Mathematics and Statistics, University of Sheffield, Sheffield, S3 7RH, UK.
| | - Alex Best
- School of Mathematics and Statistics, University of Sheffield, Sheffield, S3 7RH, UK
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29
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Yu JH, Durrant KL, Liu S, Carlin EP, Wang C, Rodriguez J, Bratthauer A, Walsh T, Valitutto MT, Fine L, Murray S, Fleischer RC. First Report of a Novel Hepatozoon sp. in Giant Pandas (Ailuropoda melanoleuca). ECOHEALTH 2019; 16:338-345. [PMID: 31147811 DOI: 10.1007/s10393-019-01416-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 03/19/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
The first report of giant pandas (Ailuropoda melanoleuca) infected with a novel Hepatozoon species is presented. An intraleukocytic parasite was detected via routine blood smear from a zoo-housed giant panda at the National Zoological Park. Ribosomal DNA sequences indicated a previously undescribed Hepatozoon species. Phylogenetic and distance analyses of the sequences placed it within its own branch, clustered with Old World species with carnivore (primarily ursid and mustelid) hosts. Retrospective and opportunistic testing of other individuals produced additional positive detections (17/23, 73.9%), demonstrating 100% prevalence (14/14) across five institutions. All animals were asymptomatic at time of sampling, and health implications for giant pandas remain unknown.
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Affiliation(s)
- Jennifer H Yu
- Global Health Program, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, 20008, USA.
| | - Kate L Durrant
- School of Life Sciences, University of Nottingham, Nottingham, UK
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, 20008, USA
| | - Songrui Liu
- Chengdu Research Base of Giant Panda Breeding, Chengdu, Sichuan, People's Republic of China
| | - Ellen P Carlin
- Global Health Program, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, 20008, USA
- EcoHealth Alliance, New York, NY, USA
| | - Chengdong Wang
- Chengdu Research Base of Giant Panda Breeding, Chengdu, Sichuan, People's Republic of China
| | - Juan Rodriguez
- Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, 20008, USA
| | - Ann Bratthauer
- Department of Pathology, Smithsonian National Zoological Park, Washington, DC, USA
| | - Tim Walsh
- College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Marc T Valitutto
- Global Health Program, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, 20008, USA
| | - Leah Fine
- Washington University in St. Louis, St. Louis, MO, USA
| | - Suzan Murray
- Global Health Program, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, 20008, USA
| | - Robert C Fleischer
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, 20008, USA
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30
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Cobb RC, Ross N, Hayden KJ, Eyre CA, Dodd RS, Frankel SJ, Garbelotto M, Rizzo DM. Promise and Pitfalls of Endemic Resistance for Cultural Resources Threatened by Phytophthora ramorum. PHYTOPATHOLOGY 2019; 109:760-769. [PMID: 30303771 DOI: 10.1094/phyto-04-18-0142-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Invasive forest pathogens can harm cultural, economic, and ecological resources. Here, we demonstrate the potential of endemic tree pathogen resistance in forest disease management using Phytophthora ramorum, cause of sudden oak death, in the context of management of tanoak (Notholithocarpus densiflorus), an ecologically unique and highly valued tree within Native American communities of northern California and southern Oregon in the United States. We surveyed resistance to P. ramorum on the Hoopa Valley Indian Reservation and Yurok Indian Reservation in a set of study sites with variable management intensities. Variation in resistance was found at all sites with similar mean and variation across stands, and resistance tended to have a random spatial distribution within stands but was not associated with previous stand management (thinning or prescribed fire) or structural characteristics such as tree density, basal area, or pairwise relatedness among study trees. These results did not suggest host, genetic, management, or environment interactions that could be easily leveraged into treatments to increase the prevalence of resistant trees. We applied epidemiological models to assess the potential application of endemic resistance in this system and to examine our assumption that in planta differences in lesion size-our measure of resistance-reflect linkages between mortality and transmission (resistance) versus reduced mortality with no change in transmission (tolerance). This assumption strongly influenced infection dynamics but changes in host populations-our conservation focus-was dependent on community-level variation in transmission. For P. ramorum, slowing mortality rates (whether by resistance or tolerance) conserves host resources when a second source of inoculum is present; these results are likely generalizable to pathogens with a broader host range. However, when the focal host is the sole source of inoculum, increasing tolerant individuals led to the greatest stand-level pathogen accumulation in our model. When seeking to use variation in mortality rates to affect conservation strategies, it is important to understand how these traits are linked with transmission because tolerance will be more useful for management in mixed-host stands that are already invaded, compared with single-host stands with low or no pathogen presence, where resistance will have the greatest conservation benefits.
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Affiliation(s)
- Richard C Cobb
- 1 Department of Natural Resources & Environmental Science, California Polytechnic State University, San Luis Obispo 93407, U.S.A
| | - Noam Ross
- 2 EcoHealth Alliance, 460 W 34th St, New York 10001, U.S.A
| | - Katherine J Hayden
- 3 Royal Botanic Garden Edinburgh, 20a Inverleith Row, Edinburgh, EH3 5LR, United Kingdom
- 4 Department of Environmental Science, Policy and Management, University of California-Berkeley 94720, U.S.A
| | - Catherine A Eyre
- 4 Department of Environmental Science, Policy and Management, University of California-Berkeley 94720, U.S.A
| | - Richard S Dodd
- 4 Department of Environmental Science, Policy and Management, University of California-Berkeley 94720, U.S.A
| | - Susan J Frankel
- 5 Pacific Southwest Research Station, 800 Buchanan Street, Albany, CA 94710, U.S.A.; and
| | - Matteo Garbelotto
- 4 Department of Environmental Science, Policy and Management, University of California-Berkeley 94720, U.S.A
| | - David M Rizzo
- 6 Department of Plant Pathology, University of California, One Shields Ave., Davis 95616, U.S.A
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31
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Vitale C, Best A. The paradox of tolerance: Parasite extinction due to the evolution of host defence. J Theor Biol 2019; 474:78-87. [PMID: 31051178 DOI: 10.1016/j.jtbi.2019.04.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 04/24/2019] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
Abstract
Host defence against parasite infection can rely on two broad strategies: resistance and tolerance. The spread of resistance traits usually lowers parasite prevalence and decreases selection for higher defence. Conversely, tolerance mechanisms increase parasite prevalence and foster selection for more tolerance. Here we examine the potential for the host to drive parasites to extinction through the evolution of one or other defence mechanism. We analysed theoretical models of resistance and tolerance evolution in both the absence and the presence of a trade-off between defence and reproduction. In the absence of costs, resistance evolves towards maximisation and, consequently, parasite extinction. Tolerance also evolves towards maximisation but the positive feedback between tolerance and disease prevents the disappearance of the parasite. On the contrary, when defence comes with costs it is impossible for the host to eliminate the infection through resistance, because costly resistance is selected against when parasites are at low prevalence. We uncover that the only path to disease clearance in the presence of costs is through tolerance. Paradoxically, however, it is by lowering tolerance -and hence increasing disease-induced mortality- that extinction can occur. We also show that such extinction can occur even in the case of parasite counter-adaptation. Our results emphasise the importance of tolerance as a defence strategy, and identify key questions for future research.
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Affiliation(s)
- Caterina Vitale
- School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom.
| | - Alex Best
- School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, United Kingdom.
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32
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Masini L, Grenville‐Briggs LJ, Andreasson E, Råberg L, Lankinen Å. Tolerance and overcompensation to infection by Phytophthora infestans in the wild perennial climber Solanum dulcamara. Ecol Evol 2019; 9:4557-4567. [PMID: 31031927 PMCID: PMC6476776 DOI: 10.1002/ece3.5057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 02/16/2019] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
Studies of infection by Phytophthora infestans-the causal agent of potato late blight-in wild species can provide novel insights into plant defense responses, and indicate how wild plants might be influenced by recurrent epidemics in agricultural fields. In the present study, our aim was to investigate if different clones of Solanum dulcamara (a relative of potato) collected in the wild differ in resistance and tolerance to infection by a common European isolate of P. infestans. We performed infection experiments with six S. dulcamara genotypes (clones) both in the laboratory and in the field and measured the degree of infection and plant performance traits. In the laboratory, the six evaluated genotypes varied from resistant to susceptible, as measured by degree of infection 20 days post infection. Two of the four genotypes susceptible to infection showed a quadratic (concave downward) relationship between the degree of infection and shoot length, with maximum shoot length at intermediate values of infection. This result suggests overcompensation, that is, an increase in growth in infected individuals. The number of leaves decreased with increasing degree of infection, but at different rates in the four susceptible genotypes, indicating genetic variation for tolerance. In the field, the inoculated genotypes did not show any disease symptoms, but plant biomass at the end of the growing season was higher for inoculated plants than for controls, in-line with the overcompensation detected in the laboratory. We conclude that in S. dulcamara there are indications of genetic variation for both resistance and tolerance to P. infestans infection. Moreover, some genotypes displayed overcompensation. Learning about plant tolerance and overcompensation to infection by pathogens can help broaden our understanding of plant defense in natural populations and help develop more sustainable plant protection strategies for economically important crop diseases.
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Affiliation(s)
- Laura Masini
- Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
- Present address:
British American TobaccoPlant Biotechnology DivisionCambridgeUK
| | | | - Erik Andreasson
- Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
| | - Lars Råberg
- Department of BiologyLund UniversityLundSweden
| | - Åsa Lankinen
- Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
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33
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Marwaha J, Aase H, Geist J, Stoeckle BC, Kuehn R, Jakobsen PJ. Host (Salmo trutta) age influences resistance to infestation by freshwater pearl mussel (Margaritifera margaritifera) glochidia. Parasitol Res 2019; 118:1519-1532. [DOI: 10.1007/s00436-019-06300-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/20/2019] [Indexed: 11/28/2022]
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34
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Burgan SC, Gervasi SS, Johnson LR, Martin LB. How Individual Variation in Host Tolerance Affects Competence to Transmit Parasites. Physiol Biochem Zool 2019; 92:49-57. [PMID: 30481116 DOI: 10.1086/701169] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Tolerance, or the maintenance of host health or fitness at a given parasite burden, has often been studied in evolutionary and medical contexts, particularly with respect to effects on the evolution of parasite virulence and individual patient outcomes. These bodies of work have provided insight about tolerance for evolutionary phenomena (e.g., virulence) and individual health (e.g., recovering from an infection). However, due to the specific motivations of that work, few studies have considered the ecological ramifications of variation in tolerance, namely, how variation in forms of tolerance could mediate parasite movement through populations and even community-level disease dynamics. Tolerance is most commonly regarded as the relationship between host fitness and parasite burden. However, few if any studies have actually quantified host fitness, instead utilizing proxies of fitness as the response variables to be regressed against parasite burden. Here, we address how attention to the effects of parasite burden on traits that are relevant to host competence (i.e., the ability to amplify parasites to levels transmissible to other hosts/vectors) will enhance our understanding of disease dynamics in nature. We also provide several forms of guidance for how to overcome the challenges of quantifying tolerance in wild organisms.
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35
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Ruiz-Aravena M, Jones ME, Carver S, Estay S, Espejo C, Storfer A, Hamede RK. Sex bias in ability to cope with cancer: Tasmanian devils and facial tumour disease. Proc Biol Sci 2018; 285:rspb.2018.2239. [PMID: 30464069 DOI: 10.1098/rspb.2018.2239] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 11/01/2018] [Indexed: 02/07/2023] Open
Abstract
Knowledge of the ecological dynamics between hosts and pathogens during the initial stages of disease emergence is crucial to understanding the potential for evolution of new interspecific interactions. Tasmanian devil (Sarcophilus harrisii) populations have declined precipitously owing to infection by a transmissible cancer (devil facial tumour disease, DFTD) that emerged approximately 20 years ago. Since the emergence of DFTD, and as the disease spreads across Tasmania, the number of devils has dropped up to 90% across 80% of the species's distributional range. As a result, the disease is expected to act as a strong selective force on hosts to develop mechanisms of tolerance and/or resistance to the infection. We assessed the ability of infected devils to cope with infection, which translates into host tolerance to the cancer, by using the reaction norm of the individual body condition by tumour burden. We found that body condition of infected hosts is negatively affected by cancer progression. Males and females presented significant differences in their tolerance levels to infection, with males suffering declines of up to 25% of their body condition, in contrast to less than 5% in females. Sex-related differences in tolerance to cancer progression may select for changes in life-history strategies of the host and could also alter the selective environment for the tumours.
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Affiliation(s)
| | - Menna E Jones
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Scott Carver
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Sergio Estay
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.,Center of Applied Ecology and Sustainability, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Camila Espejo
- School of Medicine, University of Tasmania, Hobart, Australia
| | - Andrew Storfer
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Rodrigo K Hamede
- School of Natural Sciences, University of Tasmania, Hobart, Australia
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36
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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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37
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Lissner MM, Schneider DS. The physiological basis of disease tolerance in insects. CURRENT OPINION IN INSECT SCIENCE 2018; 29:133-136. [PMID: 30551820 DOI: 10.1016/j.cois.2018.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 09/10/2018] [Indexed: 06/09/2023]
Abstract
Immunology textbooks teach us about the ways hosts can recognize and kill microbes but leave out something important: the mechanisms used to survive infections. Survival depends on more than simply detecting and eliminating microbes; it requires that we prevent and repair the damage caused by pathogens and the immune response. Recent work in insects is helping to build our understanding of this aspect of pathology, called disease tolerance. Here we discuss papers that explore disease tolerance using theoretical, population genetics, and mechanistic approaches.
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Affiliation(s)
- Michelle M Lissner
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, United States
| | - David S Schneider
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, United States.
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39
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Shukla A, Pagán I, García‐Arenal F. Effective tolerance based on resource reallocation is a virus-specific defence in Arabidopsis thaliana. MOLECULAR PLANT PATHOLOGY 2018; 19:1454-1465. [PMID: 29027740 PMCID: PMC6638070 DOI: 10.1111/mpp.12629] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 05/27/2023]
Abstract
Plant viruses often harm their hosts, which have developed mechanisms to prevent or minimize the effects of virus infection. Resistance and tolerance are the two main plant defences to pathogens. Although resistance to plant viruses has been studied extensively, tolerance has received much less attention. Theory predicts that tolerance to low-virulent parasites would be achieved through resource reallocation from growth to reproduction, whereas tolerance to high-virulent parasites would be attained through shortening of the pre-reproductive period. We have shown previously that the tolerance of Arabidopsis thaliana to Cucumber mosaic virus (CMV), a relatively low-virulent virus in this host, accords to these predictions. However, whether other viruses trigger the same response, and how A. thaliana copes with highly virulent virus infections remains unexplored. To address these questions, we challenged six A. thaliana wild genotypes with five viruses with different genomic structures, life histories and transmission modes. In these plants, we quantified virus multiplication, virulence, and the effects of infection on plant growth and reproduction, and on the developmental schedule. Our results indicate that virus multiplication varies according to the virus × host genotype interaction. Conversely, effective tolerance is observed only on CMV infection, and is associated with resource reallocation from growth to reproduction. Tolerance to the other viruses is observed only in specific host-virus combinations and, at odds with theoretical predictions, is linked to longer pre-reproductive periods. These findings only partially agree with theoretical predictions, and contribute to a better understanding of pathogenic processes in plant-virus interactions.
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Affiliation(s)
- Aayushi Shukla
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA, E.T.S.I. Agronómica, Agroalimentaria y de Biosistemas, Campus de MontegancedoUniversidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid) 28223Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA, E.T.S.I. Agronómica, Agroalimentaria y de Biosistemas, Campus de MontegancedoUniversidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid) 28223Spain
| | - Fernando García‐Arenal
- Centro de Biotecnología y Genómica de Plantas UPM‐INIA, E.T.S.I. Agronómica, Agroalimentaria y de Biosistemas, Campus de MontegancedoUniversidad Politécnica de Madrid, Pozuelo de Alarcón (Madrid) 28223Spain
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40
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Burgan SC, Gervasi SS, Martin LB. Parasite Tolerance and Host Competence in Avian Host Defense to West Nile Virus. ECOHEALTH 2018; 15:360-371. [PMID: 29569179 DOI: 10.1007/s10393-018-1332-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 02/15/2018] [Accepted: 03/07/2018] [Indexed: 06/08/2023]
Abstract
Competence, or the propensity of a host to transmit parasites, is partly underlain by host strategies to cope with infection (e.g., resistance and tolerance). Resistance represents the ability of hosts to prevent or clear infections, whereas tolerance captures the ability of individuals to cope with a given parasite burden. Here, we investigated (1) whether one easy-to-measure form of tolerance described well the dynamic relationships between host health and parasite burden, and (2) whether individual resistance and tolerance to West Nile virus (WNV) were predictable from single cytokine measures. We exposed house sparrows (HOSP) to WNV and measured subsequent changes in host performance, viral burden, and cytokine expression. We then used two novel approaches (one complex, one simpler) to estimate tolerance within-individual HOSP using four separate host performance traits. We lastly investigated changes in the expression of pro-inflammatory cytokine interferon-γ (IFN-γ) and anti-inflammatory cytokine interleukin-10 (IL-10). Both approaches to estimating tolerance were equivalent among WNV-infected HOSP; thus, an easy-to-measure tolerance estimation may be successfully applied in field studies. Constitutive expression of IFN-γ and IL-10 were predictive of resistance and tolerance to WNV, implicating these cytokines as viable biomarkers of host competence to WNV.
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Affiliation(s)
- Sarah C Burgan
- Department of Integrative Biology, University of South Florida, SCA 130, 12037 USF Beard Drive, Tampa, FL, 33620, USA
| | | | - Lynn B Martin
- Department of Integrative Biology, University of South Florida, SCA 130, 12037 USF Beard Drive, Tampa, FL, 33620, USA.
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41
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Hozé N, Bonhoeffer S, Regoes R. Assessing the public health impact of tolerance-based therapies with mathematical models. PLoS Comput Biol 2018; 14:e1006119. [PMID: 29727455 PMCID: PMC5955582 DOI: 10.1371/journal.pcbi.1006119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/16/2018] [Accepted: 04/03/2018] [Indexed: 12/18/2022] Open
Abstract
Disease tolerance is a defense strategy against infections that aims at maintaining host health even at high pathogen replication or load. Tolerance mechanisms are currently intensively studied with the long-term goal of exploiting them therapeutically. Because tolerance-based treatment imposes less selective pressure on the pathogen it has been hypothesised to be “evolution-proof”. However, the primary public health goal is to reduce the incidence and mortality associated with a disease. From this perspective, tolerance-based treatment bears the risk of increasing the prevalence of the disease, which may lead to increased mortality. We assessed the promise of tolerance-based treatment strategies using mathematical models. Conventional treatment was implemented as an increased recovery rate, while tolerance-based treatment was assumed to reduce the disease-related mortality of infected hosts without affecting recovery. We investigated the endemic phase of two types of infections: acute and chronic. Additionally, we considered the effect of pathogen resistance against conventional treatment. We show that, for low coverage of tolerance-based treatment, chronic infections can cause even more deaths than without treatment. Overall, we found that conventional treatment always outperforms tolerance-based treatment, even when we allow the emergence of pathogen resistance. Our results cast doubt on the potential benefit of tolerance-based over conventional treatment. Any clinical application of tolerance-based treatment of infectious diseases has to consider the associated detrimental epidemiological feedback. Conventional therapies improve patient health by eliminating the pathogen, or, at least, reducing its burden. Recently, alternative therapies that exploit host tolerance mechanisms have received attention from the medical community as a promising strategy. These treatments aim at reducing the level of illness due to the infection, rather than eliminating the pathogen directly. Using a mathematical model, we show that although these treatments are beneficial at the individual level, they can have undesired public health consequences. In particular we show that tolerance-based treatment gives more time for the disease to spread in the population, which in turn increase its prevalence. Moreover, in the case of a low coverage of the treatment of a chronic infection, the overall mortality can increase.
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Affiliation(s)
- Nathanaël Hozé
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- * E-mail: (NH); (RR)
| | | | - Roland Regoes
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- * E-mail: (NH); (RR)
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Conlon BH, Frey E, Rosenkranz P, Locke B, Moritz RFA, Routtu J. The role of epistatic interactions underpinning resistance to parasitic Varroa mites in haploid honey bee (Apis mellifera) drones. J Evol Biol 2018; 31:801-809. [PMID: 29577506 DOI: 10.1111/jeb.13271] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 01/25/2023]
Abstract
The Red Queen hypothesis predicts that host-parasite coevolutionary dynamics can select for host resistance through increased genetic diversity, recombination and evolutionary rates. However, in haplodiploid organisms such as the honeybee (Apis mellifera), models suggest the selective pressure is weaker than in diploids. Haplodiploid sex determination, found in A. mellifera, can allow deleterious recessive alleles to persist in the population through the diploid sex with negative effects predominantly expressed in the haploid sex. To overcome these negative effects in haploid genomes, epistatic interactions have been hypothesized to play an important role. Here, we use the interaction between A. mellifera and the parasitic mite Varroa destructor to test epistasis in the expression of resistance, through the inhibition of parasite reproduction, in haploid drones. We find novel loci on three chromosomes which explain over 45% of the resistance phenotype. Two of these loci interact only additively, suggesting their expression is independent of each other, but both loci interact epistatically with the third locus. With drone offspring inheriting only one copy of the queen's chromosomes, the drones will only possess one of two queen alleles throughout the years-long lifetime of the honeybee colony. Varroa, in comparison, completes its highly inbred reproductive cycle in a matter of weeks, allowing it to rapidly evolve resistance. Faced with the rapidly evolving Varroa, a diversity of pathways and epistatic interactions for the inhibition of Varroa reproduction could therefore provide a selective advantage to the high levels of recombination seen in A. mellifera. This allows for the remixing of phenotypes despite a fixed queen genotype.
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Affiliation(s)
- Benjamin H Conlon
- Molecular Ecology, Institute of Biology/Zoology, Martin-Luther-University Halle-Wittenberg, Halle an der Saale, Germany
| | - Eva Frey
- Apicultural State Institute, University of Hohenheim, Stuttgart, Germany
| | - Peter Rosenkranz
- Apicultural State Institute, University of Hohenheim, Stuttgart, Germany
| | - Barbara Locke
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Robin F A Moritz
- Molecular Ecology, Institute of Biology/Zoology, Martin-Luther-University Halle-Wittenberg, Halle an der Saale, Germany
| | - Jarkko Routtu
- Molecular Ecology, Institute of Biology/Zoology, Martin-Luther-University Halle-Wittenberg, Halle an der Saale, Germany
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Kutzer MAM, Kurtz J, Armitage SAO. Genotype and diet affect resistance, survival, and fecundity but not fecundity tolerance. J Evol Biol 2017; 31:159-171. [DOI: 10.1111/jeb.13211] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/06/2017] [Accepted: 11/12/2017] [Indexed: 11/29/2022]
Affiliation(s)
- M. A. M. Kutzer
- Institute for Evolution and Biodiversity; University of Münster; Münster Germany
| | - J. Kurtz
- Institute for Evolution and Biodiversity; University of Münster; Münster Germany
| | - S. A. O. Armitage
- Institute for Evolution and Biodiversity; University of Münster; Münster Germany
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Recent evolution of extreme cestode growth suppression by a vertebrate host. Proc Natl Acad Sci U S A 2017; 114:6575-6580. [PMID: 28588142 DOI: 10.1073/pnas.1620095114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Parasites can be a major cause of natural selection on hosts, which consequently evolve a variety of strategies to avoid, eliminate, or tolerate infection. When ecologically similar host populations present disparate infection loads, this natural variation can reveal immunological strategies underlying adaptation to infection and population divergence. For instance, the tapeworm Schistocephalus solidus persistently infects 0-80% of threespine stickleback (Gasterosteus aculeatus) in lakes on Vancouver Island. To test whether these heterogeneous infection rates result from evolved differences in immunity, we experimentally exposed laboratory-reared fish from ecologically similar high-infection and no-infection populations to controlled doses of Schistocephalus We observed heritable between-population differences in several immune traits: Fish from the naturally uninfected population initiated a stronger granulocyte response to Schistocephalus infection, and their granulocytes constitutively generate threefold more reactive oxygen species in cell culture. Despite these immunological differences, Schistocephalus was equally successful at establishing initial infections in both host populations. However, the no-infection fish dramatically suppressed tapeworm growth relative to high-infection fish, and parasite size was intermediate in F1 hybrid hosts. Our results show that stickleback recently evolved heritable variation in their capacity to suppress helminth growth by two orders of magnitude. Data from many natural populations indicate that growth suppression is widespread but not universal and, when present, is associated with reduced infection prevalence. Host suppression of helminth somatic growth may be an important immune strategy that aids in parasite clearance or in mitigating the fitness costs of persistent infection.
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Soler JJ, Soler M. Evolutionary change: facultative virulence by brood parasites and tolerance and plastic resistance by hosts. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Meunier I, Kaufmann E, Downey J, Divangahi M. Unravelling the networks dictating host resistance versus tolerance during pulmonary infections. Cell Tissue Res 2017; 367:525-536. [PMID: 28168323 PMCID: PMC7088083 DOI: 10.1007/s00441-017-2572-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 01/05/2017] [Indexed: 12/19/2022]
Abstract
The appearance of single cell microorganisms on earth dates back to more than 3.5 billion years ago, ultimately leading to the development of multicellular organisms approximately 3 billion years later. The evolutionary burst of species diversity and the “struggle for existence”, as proposed by Darwin, generated a complex host defense system. Host survival during infection in vital organs, such as the lung, requires a delicate balance between host defense, which is essential for the detection and elimination of pathogens and host tolerance, which is critical for minimizing collateral tissue damage. Whereas the cellular and molecular mechanisms of host defense against many invading pathogens have been extensively studied, our understanding of host tolerance as a key mechanism in maintaining host fitness is extremely limited. This may also explain why current therapeutic and preventive approaches targeting only host defense mechanisms have failed to provide full protection against severe infectious diseases, including pulmonary influenza virus and Mycobacterium tuberculosis infections. In this review, we aim to outline various host strategies of resistance and tolerance for effective protection against acute or chronic pulmonary infections.
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Affiliation(s)
- Isabelle Meunier
- Department of Medicine, Department of Microbiology & Immunology, and Department of Pathology, McGill University Health Centre, McGill International TB Centre, Meakins-Christie Laboratories, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada
| | - Eva Kaufmann
- Department of Medicine, Department of Microbiology & Immunology, and Department of Pathology, McGill University Health Centre, McGill International TB Centre, Meakins-Christie Laboratories, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada
| | - Jeffrey Downey
- Department of Medicine, Department of Microbiology & Immunology, and Department of Pathology, McGill University Health Centre, McGill International TB Centre, Meakins-Christie Laboratories, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada
| | - Maziar Divangahi
- Department of Medicine, Department of Microbiology & Immunology, and Department of Pathology, McGill University Health Centre, McGill International TB Centre, Meakins-Christie Laboratories, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada. .,RI-MUHC, Centre for Translational Biology, Meakins-Christie Laboratories, McGill University, 1001 Decarie Boulevard, Block E (EM3.2248), Montreal, Quebec, H4A 3J1, Canada.
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Adelman JS, Hawley DM. Tolerance of infection: A role for animal behavior, potential immune mechanisms, and consequences for parasite transmission. Horm Behav 2017; 88:79-86. [PMID: 27984034 DOI: 10.1016/j.yhbeh.2016.10.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/24/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
Abstract
Infected organisms can resist or tolerate infection, with tolerance of infection defined as minimizing per-parasite reductions in fitness. Although tolerance is well studied in plants, researchers have only begun to probe the mechanisms and transmission consequences of tolerance in animals. Here we suggest that research on tolerance in animals would benefit from explicitly incorporating behavior as a component of tolerance, given the importance of behavior for host fitness and parasite transmission. We propose two distinct manifestations of tolerance in animals: tissue-specific tolerance, which minimizes fitness losses due to tissue damage during infection, and behavioral tolerance, which minimizes fitness losses by maintaining normal, fitness-enhancing behaviors during infection. Here we briefly review one set of potential immune mechanisms underlying both responses in vertebrate animals: inflammation and its associated signaling molecules. Inflammatory responses, including broadly effective resistance mechanisms like the production of reactive oxygen species, can incur severe costs in terms of damage to a host's own tissues, thereby reducing tissue-specific tolerance. In addition, signaling molecules involved in these responses facilitate stereotypical behavioral changes during infection, which include lethargy and anorexia, reducing normal behaviors and behavioral tolerance. We consider how tissue-specific and behavioral tolerance may vary independently or in conjunction and outline potential consequences of such covariation for the transmission of infectious diseases. We put forward the distinction between tissue-specific and behavioral tolerance not as a definitive framework, but to help stimulate and broaden future research by considering animal behavior as intimately linked to the mechanisms and consequences of tolerance in animals.
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Affiliation(s)
- James S Adelman
- Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, 2310 Pammel Dr., Ames, IA 50011, United States.
| | - Dana M Hawley
- Department of Biological Sciences, Virginia Tech, 1405 Perry St. Blacksburg, VA 24061, United States.
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Kurze C, Routtu J, Moritz RF. Parasite resistance and tolerance in honeybees at the individual and social level. ZOOLOGY 2016; 119:290-7. [DOI: 10.1016/j.zool.2016.03.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 02/15/2016] [Accepted: 03/23/2016] [Indexed: 12/01/2022]
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50
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Anaya-Rojas JM, Brunner FS, Sommer N, Seehausen O, Eizaguirre C, Matthews B. The association of feeding behaviour with the resistance and tolerance to parasites in recently diverged sticklebacks. J Evol Biol 2016; 29:2157-2167. [DOI: 10.1111/jeb.12934] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/28/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Jaime M. Anaya-Rojas
- Center of Ecology, Evolution and Biogeochemistry; Aquatic Ecology Department; Eawag; Kastanienbaum Switzerland
- Center of Ecology, Evolution and Biogeochemistry; Department of Fish Ecology and Evolution; Eawag; Kastanienbaum Switzerland
- Division of Aquatic Ecology and Macroevolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
| | - Franziska S. Brunner
- School of Biological and Chemical Sciences; Queen Mary University of London; London UK
| | - Nina Sommer
- Center of Ecology, Evolution and Biogeochemistry; Aquatic Ecology Department; Eawag; Kastanienbaum Switzerland
| | - Ole Seehausen
- Center of Ecology, Evolution and Biogeochemistry; Department of Fish Ecology and Evolution; Eawag; Kastanienbaum Switzerland
- Division of Aquatic Ecology and Macroevolution; Institute of Ecology and Evolution; University of Bern; Bern Switzerland
| | - Christophe Eizaguirre
- School of Biological and Chemical Sciences; Queen Mary University of London; London UK
| | - Blake Matthews
- Center of Ecology, Evolution and Biogeochemistry; Aquatic Ecology Department; Eawag; Kastanienbaum Switzerland
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