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Aulsebrook LC, Wong BBM, Hall MD. Pharmaceutical pollution alters the cost of bacterial infection and its relationship to pathogen load. Proc Biol Sci 2024; 291:20231273. [PMID: 38196353 PMCID: PMC10777164 DOI: 10.1098/rspb.2023.1273] [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: 06/08/2023] [Accepted: 12/01/2023] [Indexed: 01/11/2024] Open
Abstract
The relationship between pathogen proliferation and the cost of infection experienced by a host drives the ecology and evolution of host-pathogen dynamics. While environmental factors can shape this relationship, there is currently limited knowledge on the consequences of emerging contaminants, such as pharmaceutical pollutants, on the relationship between a pathogen's growth within the host and the damage it causes, termed its virulence. Here, we investigated how exposure to fluoxetine (Prozac), a commonly detected psychoactive pollutant, could alter this key relationship using the water flea Daphnia magna and its bacterial pathogen Pasteuria ramosa as a model system. Across a variety of fluoxetine concentrations, we found that fluoxetine shaped the damage a pathogen caused, such as the reduction in fecundity or intrinsic growth experienced by infected individuals, but with minimal change in average pathogen spore loads. Instead, fluoxetine modified the relationship between the degree of pathogen proliferation and its virulence, with both the strength of this trade-off and the component of host fitness most affected varying by fluoxetine concentration and host genotype. Our study underscores the potential for pharmaceutical pollution to modify the virulence of an invading pathogen, as well as the fundamental trade-off between host and pathogen fitness, even at the trace amounts increasingly found in natural waterways.
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Affiliation(s)
- Lucinda C. Aulsebrook
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Bob B. M. Wong
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Matthew D. Hall
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
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2
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Terrill Sondag EE, Stewart Merrill TE, Drnevich J, Holmes JR, Fischer EK, Cáceres CE, Strickland LR. Differential gene expression in response to fungal pathogen exposure in the aquatic invertebrate, Daphnia dentifera. Ecol Evol 2023; 13:e10354. [PMID: 37529587 PMCID: PMC10375369 DOI: 10.1002/ece3.10354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/05/2023] [Accepted: 07/12/2023] [Indexed: 08/03/2023] Open
Abstract
While vertebrate immune systems are appreciated for their complexity and adaptability, invertebrate immunity is often considered to be less complex. However, immune responses in many invertebrates likely involve sophisticated processes. Interactions between the crustacean host Daphnia dentifera and its fungal pathogen Metschnikowia bicuspidata provide an excellent model for exploring the mechanisms underlying crustacean immunity. To explore the genomic basis of immunity in Daphnia, we used RNA-sequencing technology to quantify differential gene expression between individuals of a single host genotype exposed or unexposed to M. bicuspidata over 24 h. Transcriptomic analyses showed that the number of differentially expressed genes between the control (unexposed) and experimental (exposed) groups increased over time. Gene ontology enrichment analysis revealed that differentially expressed genes were enriched for immune-related molecules and processes, such as cuticle development, prostaglandin, and defense response processes. Our findings provide a suite of immunologically relevant genes and suggest the presence of a rapidly upregulated immune response involving the cuticle in Daphnia. Studies involving gene expression responses to pathogen exposure shine a light on the processes occurring during the course of infection. By leveraging knowledge on the genetic basis for immunity, immune mechanisms can be more thoroughly understood to refine our understanding of disease spread within invertebrate populations.
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Affiliation(s)
- Emily E. Terrill Sondag
- Department of Evolution, Ecology, and Behavior, School of Integrative BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Tara E. Stewart Merrill
- Department of Evolution, Ecology, and Behavior, School of Integrative BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Coastal and Marine LaboratoryFlorida State UniversitySt. TeresaFloridaUSA
| | - Jenny Drnevich
- High Performance Computing in BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Jessica R. Holmes
- High Performance Computing in BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Eva K. Fischer
- Department of Evolution, Ecology, and Behavior, School of Integrative BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Carla E. Cáceres
- Department of Evolution, Ecology, and Behavior, School of Integrative BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
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3
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Jensen CH, Weidner J, Giske J, Jørgensen C, Eliassen S, Mennerat A. Adaptive host responses to infection can resemble parasitic manipulation. Ecol Evol 2023; 13:e10318. [PMID: 37456066 PMCID: PMC10349281 DOI: 10.1002/ece3.10318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/22/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Using a dynamic optimisation model for juvenile fish in stochastic food environments, we investigate optimal hormonal regulation, energy allocation and foraging behaviour of a growing host infected by a parasite that only incurs an energetic cost. We find it optimal for the infected host to have higher levels of orexin, growth and thyroid hormones, resulting in higher activity levels, increased foraging and faster growth. This growth strategy thus displays several of the fingerprints often associated with parasite manipulation: higher levels of metabolic hormones, faster growth, higher allocation to reserves (i.e. parasite-induced gigantism), higher risk-taking and eventually higher predation rate. However, there is no route for manipulation in our model, so these changes reflect adaptive host compensatory responses. Interestingly, several of these changes also increase the fitness of the parasite. Our results call for caution when interpreting observations of gigantism or risky host behaviours as parasite manipulation without further testing.
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Affiliation(s)
| | | | - Jarl Giske
- Department of Biological SciencesUniversity of BergenBergenNorway
| | | | - Sigrunn Eliassen
- Department of Biological SciencesUniversity of BergenBergenNorway
| | - Adèle Mennerat
- Department of Biological SciencesUniversity of BergenBergenNorway
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4
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Orlansky S, Ben-Ami F. The parasites of my rival are my friends. Front Microbiol 2023; 14:1135252. [PMID: 37323892 PMCID: PMC10264602 DOI: 10.3389/fmicb.2023.1135252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 04/04/2023] [Indexed: 06/17/2023] Open
Abstract
The competitive exclusion principle asserts that two species cannot stably coexist in the same habitat. However, the presence of a parasite can facilitate temporary coexistence between two host species occupying the same habitat. Studies of parasite-mediated interspecific competition typically use two host species that are both susceptible to a single parasite species, as it is rare to find a resistant host species that requires a parasite to enable coexistence with a competitively superior susceptible host. We therefore investigated how two host species characterized by different susceptibility profiles affect each other when they coexist in the same habitat, by conducting two long-term mesocosm experiments in the laboratory. We followed populations of Daphnia similis coexisting with Daphnia magna, in either the presence or absence of the microsporidium Hamiltosporidium tvaerminnensis and then the bacterium Pasteuria ramosa. We found that in the absence of parasites, D. magna competitively excluded D. similis within a short period of time. However, in the presence of either parasites, the competitive ability of D. magna decreased dramatically. Our results emphasize the importance of parasites in shaping community structure and composition, by allowing coexistence of a resistant host species that would otherwise become extinct.
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5
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Melero I, González R, Elena SF. Host developmental stages shape the evolution of a plant RNA virus. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220005. [PMID: 36744567 PMCID: PMC9979778 DOI: 10.1098/rstb.2022.0005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Viruses are obligate pathogens that entirely rely on their hosts to complete their infectious cycle. The outcome of viral infections depends on the status of the host. Host developmental stage is an important but sometimes overlooked factor impacting host-virus interactions. This impact is especially relevant in a context where climate change and human activities are altering plant development. To better understand how different host developmental stages shape virus evolution, we experimentally evolved turnip mosaic virus (TuMV) on Arabidopsis thaliana at three different developmental stages: vegetative (juvenile), bolting (transition) and reproductive (mature). After infecting plants with an Arabidopsis-naive or an Arabidopsis-well-adapted TuMV isolate, we observed that hosts in later developmental stages were prone to faster and more severe infections. This observation was extended to viruses belonging to different genera. Thereafter, we experimentally evolved lineages of the naive and the well-adapted TuMV isolates in plants from each of the three developmental stages. All evolved viruses enhanced their infection traits, but this increase was more intense in viruses evolved in younger hosts. The genomic changes of the evolved viral lineages revealed mutation patterns that strongly depended on the founder viral isolate as well as on the developmental stage of the host wherein the lineages were evolved. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- Izan Melero
- Instituto de Biología Integrativa de Sistemas (CSIC - Universitat de València), Paterna, 46182 València, Spain
| | - Rubén González
- Instituto de Biología Integrativa de Sistemas (CSIC - Universitat de València), Paterna, 46182 València, Spain
| | - Santiago F. Elena
- Instituto de Biología Integrativa de Sistemas (CSIC - Universitat de València), Paterna, 46182 València, Spain,The Santa Fe Institute, Santa Fe 87501, NM, USA
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6
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Marcus E, Dagan T, Asli W, Ben-Ami F. Out of the 'host' box: extreme off-host conditions alter the infectivity and virulence of a parasitic bacterium. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220015. [PMID: 36744562 PMCID: PMC9900709 DOI: 10.1098/rstb.2022.0015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Disease agents play an important role in the ecology and life history of wild and cultivated populations and communities. While most studies focus on the adaptation of parasites to their hosts, the adaptation of free-living parasite stages to their external (off-host) environment may tell us a lot about the factors that shape the distribution of parasites. Pasteuria ramosa is an endoparasitic bacterium of the water flea Daphnia with a wide geographical distribution. Its transmission stages rest outside of the host and thus experience varying environmental regimes. We examined the life history of P. ramosa populations from four environmental conditions (i.e. groups of habitats): the factorial combinations of summer-dry water bodies or not, and winter-freeze water bodies or not. Our goal was to examine how the combination of winter temperature and summer dryness affects the parasite's ability to attach to its host and to infect it. We subjected samples of the four groups of habitats to temperatures of 20, 33, 46 and 60°C in dry and wet conditions, and exposed a susceptible clone of Daphnia magna to the treated spores. We found that spores which had undergone desiccation endured higher temperatures better than spores kept wet, both regarding attachment and subsequent infection. Furthermore, spores treated with heightened temperatures were much less infective and virulent. Even under high temperatures (60°C), exposed spores from all populations were able to attach to the host cuticle, albeit they were unable to establish infection. Our work highlights the sensitivity of a host-free resting stage of a bacterial parasite to the external environment. Long heatwaves and harsh summers, which are becoming more frequent owing to recent climate changes, may therefore pose a problem for parasite survival. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- Enav Marcus
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Tal Dagan
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Weaam Asli
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
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7
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Wittman TN, Carlson TA, Robinson CD, Bhave RS, Cox RM. Experimental removal of nematode parasites increases growth, sprint speed, and mating success in brown anole lizards. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:852-866. [PMID: 35871281 PMCID: PMC9796785 DOI: 10.1002/jez.2644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 01/07/2023]
Abstract
Parasites interact with nearly all free-living organisms and can impose substantial fitness costs by reducing host survival, mating success, and fecundity. Parasites may also indirectly affect host fitness by reducing growth and performance. However, experimentally characterizing these costs of parasitism is challenging in the wild because common antiparasite drug formulations require repeated dosing that is difficult to implement in free-living populations, and because the extended-release formulations that are commercially available for livestock and pets are not suitable for smaller animals. To address these challenges, we developed a method for the long-term removal of nematode parasites from brown anole lizards (Anolis sagrei) using an extended-release formulation of the antiparasite drug ivermectin. This treatment eliminated two common nematode parasites in captive adult males and dramatically reduced the prevalence and intensity of infection by these parasites in wild adult males and females. Experimental parasite removal significantly increased the sprint speed of captive adult males, the mating success of wild adult males, and the growth of wild juveniles of both sexes. Although parasite removal did not have any effect on survival in wild anoles, parasites may influence fitness directly through reduced mating success and indirectly through reduced growth and performance. Our method of long-term parasite manipulation via an extended-release formulation of ivermectin should be readily adaptable to many other small vertebrates, facilitating experimental tests of the extent to which parasites affect host phenotypes, fitness, and eco-evolutionary dynamics in the wild.
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Affiliation(s)
- Tyler N. Wittman
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Torun A. Carlson
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
| | | | - Rachana S. Bhave
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Robert M. Cox
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
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8
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Spaan JM, Leavitt N, Shen J, Bundy T, Burrows L, Ingram C, Maehara TR, Ndungu I, Mutuku M, Owino G, Odiere M, Steinauer ML. Genotypic-specific heat shock response of vector susceptibility to Schistosoma mansoni. Ecosphere 2022; 13:e4207. [PMID: 36590709 PMCID: PMC9797131 DOI: 10.1002/ecs2.4207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/27/2022] [Indexed: 01/05/2023] Open
Abstract
Living organisms are vulnerable to thermal stress which causes a diversity of physiological outcomes. Previous work has shown that the snail vectors (Biomphalaria glabrata) of an important human pathogen, Schistosoma mansoni, revert from resistant to susceptible after short exposure to a heat stress as low as 31oC; however, due to lack of replicability among labs and genetic lines of snails, it has been hypothesized that this effect is genotype dependent. We examined the effects of heat shock on resistance of two species of snail vectors including B. glabrata and B. sudanica. We used 3 different inbred laboratory snail lines in addition to the F1 generation of field collected snails from Lake Victoria, Kenya, an area with high levels of schistosomiasis transmission. Our results showed marginal effects of heat shock on prevalence of infection in B. glabrata, and that this response was genotype specific. We found no evidence of a heat shock effect on prevalence of infection in B. sudanica or on intensity of infection (number of infectious stages shed) in either snail species. Such environmentally influenced defense responses stress the importance of considering this unique interaction between snail and parasite genotypes in determining infection dynamics under climate changes.
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Affiliation(s)
- Johannie M. Spaan
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Nathaniel Leavitt
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Jessica Shen
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Taylor Bundy
- Department of Medicine, Oregon Health and Science University, Portland, Oregon 97239
| | - Lillian Burrows
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Christopher Ingram
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Thomas R. Maehara
- M.D. School of Medicine, Western Michigan University Home Stryker, Kalamazoo, Michigan 49001
| | - Ibrahim Ndungu
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Martin Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - George Owino
- Neglected Tropical Diseases Unit, Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Maurice Odiere
- Neglected Tropical Diseases Unit, Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Michelle L. Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
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9
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Hector TE, Hoang KL, Li J, King KC. Symbiosis and host responses to heating. Trends Ecol Evol 2022; 37:611-624. [PMID: 35491290 DOI: 10.1016/j.tree.2022.03.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 03/22/2022] [Accepted: 03/28/2022] [Indexed: 12/31/2022]
Abstract
Virtually all organisms are colonized by microbes. Average temperatures are rising because of global climate change - accompanied by increases in extreme climatic events and heat shock - and symbioses with microbes may determine species persistence in the 21st century. Although parasite infection typically reduces host upper thermal limits, interactions with beneficial microbes can facilitate host adaptation to warming. The effects of warming on the ecology and evolution of the microbial symbionts remain understudied but are important for understanding how climate change might affect host health and disease. We present a framework for untangling the contributions of symbiosis to predictions of host persistence in the face of global change.
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Affiliation(s)
- Tobias E Hector
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Kim L Hoang
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford OX1 3SZ, UK
| | - Jingdi Li
- 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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10
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Paraskevopoulou S, Gattis S, Ben-Ami F. Parasite resistance and parasite tolerance: insights into transgenerational immune priming in an invertebrate host. Biol Lett 2022; 18:20220018. [PMID: 35382587 PMCID: PMC8984330 DOI: 10.1098/rsbl.2022.0018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Parasites impose different selection regimes on their hosts, which respond by increasing their resistance and/or tolerance. Parental challenge with parasites can enhance the immune response of their offspring, a phenomenon documented in invertebrates and termed transgenerational immune priming. We exposed two parental generations of the model organism Daphnia magna to the horizontally transmitted parasitic yeast Metschnikowia bicuspidata and recorded resistance- and tolerance-related traits in the offspring generation. We hypothesized that parentally primed offspring will increase either their resistance or their tolerance to the parasite. Our susceptibility assays revealed no impact of parental exposure on offspring resistance. Nonetheless, different fitness-related traits, which are indicative of tolerance, were altered. Specifically, maternal priming increased offspring production and decreased survival. Grandmaternal priming positively affected age at first reproduction and negatively affected brood size at first reproduction. Interestingly, both maternal and grandmaternal priming significantly reduced within-host–parasite proliferation. Nevertheless, Daphnia primed for two consecutive generations had no competitive advantage in comparison to unprimed ones, implying additive maternal and grandmaternal effects. Our findings do not support evidence of transgenerational immune priming from bacterial infections in the same host species, thus, emphasizing that transgenerational immune responses may not be consistent even within the same host species.
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Affiliation(s)
- Sofia Paraskevopoulou
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Sabrina Gattis
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
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11
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Sequential infection of Daphnia magna by a gut microsporidium followed by a haemolymph yeast decreases transmission of both parasites. Parasitology 2021; 148:1566-1577. [PMID: 35060463 PMCID: PMC8564772 DOI: 10.1017/s0031182021001384] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Over the course of seasonal epidemics, populations of susceptible hosts may encounter a wide variety of parasites. Parasite phenology affects the order in which these species encounter their hosts, leading to sequential infections, with potentially strong effects on within-host growth and host population dynamics. Here, the cladoceran Daphnia magna was exposed sequentially to a haemolymph-infecting yeast (Metschnikowia bicuspidata) and a gut microsporidium (Ordospora colligata), with experimental treatments reflecting two possible scenarios of parasite succession. The effects of single and co-exposure were compared on parasite infectivity, spore production and the overall virulence experienced by the host. We show that neither parasite benefited from coinfection; instead, when hosts encountered Ordospora, followed by Metschnikowia, higher levels of host mortality contributed to an overall decrease in the transmission of both parasites. These results showcase an example of sequential infections generating unilateral priority effects, in which antagonistic interactions between parasites can alleviate the intensity of infection and coincide with maladaptive levels of damage inflicted on the host.
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12
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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: 89] [Impact Index Per Article: 29.7] [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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13
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Ocampo EH, Pérez García M, Nuñez JD, Luppi TA. Impact on reproductive performance and body condition in a small limpet parasitized by a large castrator pea crab. J Morphol 2021; 282:1604-1615. [PMID: 34427340 DOI: 10.1002/jmor.21409] [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: 05/13/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 11/11/2022]
Abstract
Parasitic castrators utilize the energy reserves that the host allocates on reproduction resulting in sterilization of the host. However, whether other processes (e.g., growth) are also impaired depends on the balance between the castrator's energy requirements and the available resources that the castrated host does not use in reproduction. We investigated whether the castrator pea crab Calytraeotheres garthi alters body condition, reproductive performance, and occurrence of copulation in its limpet host Bostrycapulus odites. For this purpose, we examined the anatomy of the ovary, the seminal receptacles, and the body condition of parasitized and unparasitized limpets. The histology of the female gonad of parasitized limpets revealed the ovarian tubules are smaller and characterized by a greater proportion of intertubular and intratubular free space compared with non-parasitized individuals. The body condition of female limpets from all sizes (during summer) and those larger than ~16 mm (during spring and autumn) were impacted by the pea crab. These results are in contrast to that previously reported in the comparatively larger limpet species Crepidula cachimilla, in which the same pea crab species does not alter or even increase the host body weight. We concluded this pea crab species could drastically impair its host's reproduction and body condition although deleterious effects are species-specific and likely depend on limpet body size. The histology of seminal receptacles revealed an uncommon disposition of spermatozoa (i.e., excessive debris and acrosomes detached from epithelium) in seminal receptacles of some parasitized limpets. However, this analysis failed to determine whether sperm derived from present matings or previous pea crab infection. Further studies are needed to address whether pea crabs interfere with the mating behavior of limpets and if the alterations in sperm disposition are a consequence of castration.
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Affiliation(s)
- Emiliano H Ocampo
- Instituto de Investigaciones Marinas y Costeras (IIMyC), FCEyN, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Provincia de Buenos Aires, Argentina
| | - Macarena Pérez García
- Instituto de Investigaciones Marinas y Costeras (IIMyC), FCEyN, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Provincia de Buenos Aires, Argentina
| | - Jesús D Nuñez
- Instituto de Investigaciones Marinas y Costeras (IIMyC), FCEyN, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Provincia de Buenos Aires, Argentina
| | - Tomás A Luppi
- Instituto de Investigaciones Marinas y Costeras (IIMyC), FCEyN, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Provincia de Buenos Aires, Argentina
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14
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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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15
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Andras JP, Fields PD, Du Pasquier L, Fredericksen M, Ebert D. Genome-Wide Association Analysis Identifies a Genetic Basis of Infectivity in a Model Bacterial Pathogen. Mol Biol Evol 2021; 37:3439-3452. [PMID: 32658956 PMCID: PMC7743900 DOI: 10.1093/molbev/msaa173] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/22/2020] [Accepted: 07/08/2020] [Indexed: 12/22/2022] Open
Abstract
Knowledge of the genetic architecture of pathogen infectivity and host resistance is essential for a mechanistic understanding of coevolutionary processes, yet the genetic basis of these interacting traits remains unknown for most host-pathogen systems. We used a comparative genomic approach to explore the genetic basis of infectivity in Pasteuria ramosa, a Gram-positive bacterial pathogen of planktonic crustaceans that has been established as a model for studies of Red Queen host-pathogen coevolution. We sequenced the genomes of a geographically, phenotypically, and genetically diverse collection of P. ramosa strains and performed a genome-wide association study to identify genetic correlates of infection phenotype. We found multiple polymorphisms within a single gene, Pcl7, that correlate perfectly with one common and widespread infection phenotype. We then confirmed this perfect association via Sanger sequencing in a large and diverse sample set of P. ramosa clones. Pcl7 codes for a collagen-like protein, a class of adhesion proteins known or suspected to be involved in the infection mechanisms of a number of important bacterial pathogens. Consistent with expectations under Red Queen coevolution, sequence variation of Pcl7 shows evidence of balancing selection, including extraordinarily high diversity and absence of geographic structure. Based on structural homology with a collagen-like protein of Bacillus anthracis, we propose a hypothesis for the structure of Pcl7 and the physical location of the phenotype-associated polymorphisms. Our results offer strong evidence for a gene governing infectivity and provide a molecular basis for further study of Red Queen dynamics in this model host-pathogen system.
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Affiliation(s)
- Jason P Andras
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA
| | - Peter D Fields
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Louis Du Pasquier
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Maridel Fredericksen
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Dieter Ebert
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
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16
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Bartlett LJ, Boots M. The central role of host reproduction in determining the evolution of virulence in spatially structured populations. J Theor Biol 2021; 523:110717. [PMID: 33862089 DOI: 10.1016/j.jtbi.2021.110717] [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: 05/18/2020] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
A substantial body of work has shown that local transmission selects for less acute, 'prudent' parasites that have lower virulence and transmission rates. This is because parasite strains with higher transmission rates 'self-shade' due to a combination of genetic correlations (self: clustered related parasite strains compete for susceptible individuals) and ecological correlations (shade: infected individuals clustering and blocking transmission). However, the interaction of ecological and genetic correlations alongside higher order ecological effects such as patch extinctions means that spatial evolutionary effects can be nuanced; theory has predicted that a relatively small proportion of local infection can select for highest virulence, such that there is a humped relationship between the degree of local infection and the harm that parasites are selected to cause. Here, we examine the separate roles of the interaction scales of reproduction and infection in the context of different degrees of pathogenic castration in determining virulence evolution outcomes. Our key result is that, as long as there is significant reproduction from infected individuals, local infection always selects for lower virulence, and that the prediction that a small proportion of local infection can select for higher virulence only occurs for highly castrating pathogens. The results emphasize the importance of demography for evolutionary outcomes in spatially structured populations, but also show that the core prediction that parasites are prudent in space is reasonable for the vast majority of host-parasite interactions and mixing patterns in nature.
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Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK; Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA.
| | - Mike Boots
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
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17
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Brown CR, Hannebaum SL, O’Brien VA, Page CE, Rannala B, Roche EA, Wagnon GS, Knutie SA, Moore AT, Brown MB. The cost of ectoparasitism in Cliff Swallows declines over 35 years. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1446] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Charles R. Brown
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Stacey L. Hannebaum
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Valerie A. O’Brien
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Catherine E. Page
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Bruce Rannala
- Department of Evolution and Ecology University of California Davis California 95616 USA
| | - Erin A. Roche
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Gigi S. Wagnon
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Sarah A. Knutie
- Department of Ecology and Evolutionary Biology University of Connecticut 75 N. Eagleville Rd. Storrs Connecticut 06269 USA
| | - Amy T. Moore
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Mary B. Brown
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
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18
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Izhar R, Gilboa C, Ben‐Ami F. Disentangling the steps of the infection process responsible for juvenile disease susceptibility. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Rony Izhar
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - Chen Gilboa
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - Frida Ben‐Ami
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
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19
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Lynsdale CL, Mon NO, Franco Dos Santos DJ, Aung HH, Nyein UK, Htut W, Childs D, Lummaa V. Demographic and reproductive associations with nematode infection in a long-lived mammal. Sci Rep 2020; 10:9214. [PMID: 32513991 PMCID: PMC7280280 DOI: 10.1038/s41598-020-66075-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 05/14/2020] [Indexed: 11/19/2022] Open
Abstract
Infection by macroparasites, such as nematodes, varies within vertebrate host systems; elevated infection is commonly observed in juveniles and males, and, for females, with different reproductive states. However, while such patterns are widely recognized in short-lived model systems, how they apply to long-lived hosts is comparatively understudied. Here, we investigated how infection varies with host age, sex, and female reproduction in a semi-captive population of individually marked Asian elephants Elephas maximus. We carried out 1,977 faecal egg counts (FECs) across five years to estimate nematode loads for 324 hosts. Infection patterns followed an established age-infection curve, whereby calves (5 years) exhibited the highest FECs and adults (45 years) the lowest. However, males and females had similar FECs across their long lifespan, despite distinct differences in life-history strategy and clear sexual dimorphism. Additionally, although mothers invest two years in pregnancy and a further three to five years into lactation, nematode load did not vary with four different measures of female reproduction. Our results provide a much-needed insight into the host-parasite dynamics of a long-lived host; determining host-specific associations with infection in such systems is important for broadening our knowledge of parasite ecology and provides practical applications for wildlife medicine and management.
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Affiliation(s)
| | - Nay Oo Mon
- Department of Animal Science, University of Veterinary Science, Yezin, Myanmar
| | | | - Htoo Htoo Aung
- Myanma Timber Enterprise, Ministry of Natural Resources and Environmental Conservation, Yangon, Myanmar
| | - U Kyaw Nyein
- Myanma Timber Enterprise, Ministry of Natural Resources and Environmental Conservation, Yangon, Myanmar
| | - Win Htut
- Myanma Timber Enterprise, Ministry of Natural Resources and Environmental Conservation, Yangon, Myanmar
| | - Dylan Childs
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Virpi Lummaa
- Department of Biology, University of Turku, Turku, Finland
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20
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Montes N, Vijayan V, Pagán I. Trade-offs between host tolerances to different pathogens in plant-virus interactions. Virus Evol 2020; 6:veaa019. [PMID: 32211198 PMCID: PMC7079720 DOI: 10.1093/ve/veaa019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Although accumulating evidence indicates that tolerance is a plant defence strategy against pathogens as widespread as resistance, how plants evolve tolerance is poorly understood. Theory predicts that hosts will evolve to maximize tolerance or resistance, but not both. Remarkably, most experimental works failed in finding this trade-off. We tested the hypothesis that the evolution of tolerance to one virus is traded-off against tolerance to others, rather than against resistance and identified the associated mechanisms. To do so, we challenged eighteen Arabidopsis thaliana genotypes with Turnip mosaic virus (TuMV) and Cucumber mosaic virus (CMV). We characterized plant life-history trait modifications associated with reduced effects of TuMV and CMV on plant seed production (fecundity tolerance) and life period (mortality tolerance), both measured as a norm of reaction across viral loads (range tolerance). Also, we analysed resistance-tolerance and tolerance-tolerance trade-offs. Results indicate that tolerance to TuMV is associated with changes in the length of the pre-reproductive and reproductive periods, and tolerance to CMV with resource reallocation from growth to reproduction; and that tolerance to TuMV is traded-off against tolerance to CMV in a virulence-dependent manner. Thus, this work provides novel insights on the mechanisms of plant tolerance and highlights the importance of considering the combined effect of different pathogens to understand how plant defences evolve.
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Affiliation(s)
- Nuria Montes
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and E.T.S. Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Autopista M40, km.38, Pozuelo de Alarcón, Madrid 28223, Spain.,Fisiología Vegetal, Departamento Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad San Pablo-CEU universities, Boadilla del Monte, Madrid, Spain and Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria (IIS-IP), Madrid, Spain
| | - Viji Vijayan
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and E.T.S. Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Autopista M40, km.38, Pozuelo de Alarcón, Madrid 28223, Spain.,Fisiología Vegetal, Departamento Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad San Pablo-CEU universities, Boadilla del Monte, Madrid, Spain and Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria (IIS-IP), Madrid, Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas UPM-INIA and E.T.S. Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Autopista M40, km.38, Pozuelo de Alarcón, Madrid 28223, Spain
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21
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Schedwill P, Paschkewitz S, Teubner H, Steinmetz N, Nehring V. From the host's point of view: Effects of variation in burying beetle brood care and brood size on the interaction with parasitic mites. PLoS One 2020; 15:e0228047. [PMID: 31961905 PMCID: PMC6974135 DOI: 10.1371/journal.pone.0228047] [Citation(s) in RCA: 4] [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: 06/27/2019] [Accepted: 01/06/2020] [Indexed: 11/25/2022] Open
Abstract
The fitness and virulence of parasites is often determined by how many resources they can wrangle out of their hosts. Host defenses that help to keep resources from the parasites will then reduce virulence and parasite fitness. Here, we study whether host brood care and brood size regulation can protect host fitness and harm a parasite. We use the biparental brood-caring burying beetle Nicrophorus vespilloides and its phoretic Poecilochirus carabi mites as a model. Since paternal brood care does not seem to benefit the offspring in a clean laboratory setting, the male presence has been suggested to strengthen the defense against parasites. We manipulated male presence and found no effect on the fitness of the parasitic mites or the beetle offspring. We further manipulated beetle brood size and found larger broods to reduce parasite fitness. The specific pattern we observed suggests that beetle larvae are strong competitors and consume the carrion resource before all parasites develop. They thus starve the parasites. These results shed new light on the observation that the parasites appear to reduce host brood size early on–potentially to avert later competition their offspring might have to face.
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Affiliation(s)
- Petra Schedwill
- Evolutionary Biology & Ecology, Institute of Biology I, University of Freiburg, Freiburg, Germany
| | - Sophia Paschkewitz
- Evolutionary Biology & Ecology, Institute of Biology I, University of Freiburg, Freiburg, Germany
| | - Heide Teubner
- Evolutionary Biology & Ecology, Institute of Biology I, University of Freiburg, Freiburg, Germany
| | - Nadine Steinmetz
- Evolutionary Biology & Ecology, Institute of Biology I, University of Freiburg, Freiburg, Germany
| | - Volker Nehring
- Evolutionary Biology & Ecology, Institute of Biology I, University of Freiburg, Freiburg, Germany
- * E-mail:
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22
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Sadler DE, Brunner FS, Plaistow SJ. Temperature and clone-dependent effects of microplastics on immunity and life history in Daphnia magna. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113178. [PMID: 31520904 DOI: 10.1016/j.envpol.2019.113178] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 06/10/2023]
Abstract
Microplastic (MP) pollution is potentially a major threat to many aquatic organisms. Yet we currently know very little about the mechanisms responsible for the effects of small MPs on phenotypes, and the extent to which effects of MPs are modified by genetic and environmental factors. Using a multivariate approach, we studied the effects of 500 nm polystyrene microspheres on the life history and immunity of eight clones of the freshwater cladoceran Daphnia magna reared at two temperatures (18 °C/24 °C). MP exposure altered multivariate phenotypes in half of the clones we studied but had no effect on others. In the clones that were affected, individuals exposed to MPs had smaller offspring at both temperatures, and more offspring at high temperature. Differences in response to MP exposure were unrelated to differences in particle uptake, but were instead linked to an upregulation of haemocytes, particularly at high temperature. The clone-specific, context-dependent nature of our results demonstrates the importance of incorporating genetic variation and environmental context into assessments of the impact of plastic particle exposure. Our results identify immunity as an important mechanism underpinning genetically variable responses to MP pollution and may have major implications for predicting consequences of MP pollution.
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Affiliation(s)
- Daniel E Sadler
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, L69 7ZB Liverpool, United Kingdom
| | - Franziska S Brunner
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, L69 7ZB Liverpool, United Kingdom.
| | - Stewart J Plaistow
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown Street, L69 7ZB Liverpool, United Kingdom
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23
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Within-Host Multiplication and Speed of Colonization as Infection Traits Associated with Plant Virus Vertical Transmission. J Virol 2019; 93:JVI.01078-19. [PMID: 31511374 PMCID: PMC6854480 DOI: 10.1128/jvi.01078-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 08/30/2019] [Indexed: 11/20/2022] Open
Abstract
Although vertical transmission from parents to offspring through seeds is an important fitness component of many plant viruses, very little is known about the factors affecting this process. Viruses reach the seed by direct invasion of the embryo and/or by infection of the ovules or the pollen. Thus, it can be expected that the efficiency of seed transmission would be determined by (i) virus within-host multiplication and movement, (ii) the ability of the virus to invade gametic tissues, (iii) plant seed production upon infection, and (iv) seed survival in the presence of the virus. However, these predictions have seldom been experimentally tested. To address this question, we challenged 18 Arabidopsis thaliana accessions with Turnip mosaic virus and Cucumber mosaic virus Using these plant-virus interactions, we analyzed the relationship between the effect of virus infection on rosette and inflorescence weights; short-, medium-, and long-term seed survival; virulence; the number of seeds produced per plant; virus within-host speed of movement; virus accumulation in the rosette and inflorescence; and efficiency of seed transmission measured as a percentage and as the total number of infected seeds. Our results indicate that the best estimators of percent seed transmission are the within-host speed of movement and multiplication in the inflorescence. Together with these two infection traits, virulence and the number of seeds produced per infected plant were also associated with the number of infected seeds. Our results provide support for theoretical predictions and contribute to an understanding of the determinants of a process central to plant-virus interactions.IMPORTANCE One of the major factors contributing to plant virus long-distance dispersal is the global trade of seeds. This is because more than 25% of plant viruses can infect seeds, which are the main mode of germplasm exchange/storage, and start new epidemics in areas where they were not previously present. Despite the relevance of this process for virus epidemiology and disease emergence, the infection traits associated with the efficiency of virus seed transmission are largely unknown. Using turnip mosaic and cucumber mosaic viruses and their natural host Arabidopsis thaliana as model systems, we have identified the within-host speed of virus colonization and multiplication in the reproductive structures as the main determinants of the efficiency of seed transmission. These results contribute to shedding light on the mechanisms by which plant viruses disperse and optimize their fitness and may help in the design of more-efficient strategies to prevent seed infection.
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24
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Hector TE, Sgrò CM, Hall MD. Pathogen exposure disrupts an organism's ability to cope with thermal stress. GLOBAL CHANGE BIOLOGY 2019; 25:3893-3905. [PMID: 31148326 DOI: 10.1111/gcb.14713] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/21/2019] [Indexed: 06/09/2023]
Abstract
As a result of global climate change, species are experiencing an escalation in the severity and regularity of extreme thermal events. With patterns of disease distribution and transmission predicted to undergo considerable shifts in the coming years, the interplay between temperature and pathogen exposure will likely determine the capacity of a population to persist under the dual threat of global change and infectious disease. In this study, we investigated how exposure to a pathogen affects an individual's ability to cope with extreme temperatures. Using experimental infections of Daphnia magna with its obligate bacterial pathogen Pasteuria ramosa, we measured upper thermal limits of multiple host and pathogen genotype combinations across the dynamic process of infection and under various forms (static and ramping) of thermal stress. We find that pathogens substantially limit the thermal tolerance of their host, with the reduction in upper thermal limits on par with the breadth of variation seen across similar species entire geographical ranges. The precise magnitude of any reduction, however, was specific to the host and pathogen genotype combination. In addition, as thermal ramping rate slowed, upper thermal limits of both healthy and infected individuals were reduced. Our results suggest that the capacity of a population to evolve new thermal limits, when also faced with the threat of infection, will depend not only on a host's genetic variability in warmer environments, but also on the frequency of host and pathogen genotypes. We suggest that pathogen-induced alterations of host thermal performance should be taken into account when assessing the resilience of any population and its potential for adaptation to global change.
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Affiliation(s)
- Tobias E Hector
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Melbourne, Victoria, Australia
| | - Carla M Sgrò
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Melbourne, Victoria, Australia
| | - Matthew D Hall
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Melbourne, Victoria, Australia
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25
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Hall MD, Mideo N. Linking sex differences to the evolution of infectious disease life-histories. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0431. [PMID: 30150228 DOI: 10.1098/rstb.2017.0431] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2018] [Indexed: 12/23/2022] Open
Abstract
Sex differences in the prevalence, course and severity of infection are widespread, yet the evolutionary consequences of these differences remain unclear. Understanding how male-female differences affect the trajectory of infectious disease requires connecting the contrasting dynamics that pathogens might experience within each sex to the number of susceptible and infected individuals that are circulating in a population. In this study, we build on theory using genetic covariance functions to link the growth of a pathogen within a host to the evolution and spread of disease between individuals. Using the Daphnia-Pasteuria system as a test case, we show that on the basis of within-host dynamics alone, females seem to be more evolutionarily liable for the pathogen, with higher spore loads and greater divergence among pathogen genotypes as infection progresses. Between-host transmission, however, appears to offset the lower performance of a pathogen within a male host, making even subtle differences between the sexes evolutionarily relevant, as long as the selection generated by the between-host dynamics is sufficiently strong. Our model suggests that relatively simple differences in within-host processes occurring in males and females can lead to complex patterns of genetic constraint on pathogen evolution, particularly during an expanding epidemic.This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.
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Affiliation(s)
- Matthew D Hall
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Nicole Mideo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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26
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García-Huidobro M, Varas O, George-Nascimento M, Pulgar J, Aldana M, Lardies M, Lagos N. Role of temperature and carbonate system variability on a host-parasite system: Implications for the gigantism hypothesis. Int J Parasitol Parasites Wildl 2019; 9:7-15. [PMID: 30976511 PMCID: PMC6439230 DOI: 10.1016/j.ijppaw.2019.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/21/2019] [Accepted: 03/21/2019] [Indexed: 11/02/2022]
Abstract
Biological interactions and environmental constraints alter life-history traits, modifying organismal performances. Trematode parasites often impact their hosts by inducing parasitic castration, frequently correlated with increased body size in the host (i.e., gigantism hypothesis), which is postulated to reflect the re-allocation of energy released by the reduction in the reproductive process. In this study, we compared the effect of a trematode species on shell size and morphology in adult individuals of the intertidal mussels Perumytilus purpuratus (>20 mm) collected from two local populations of contrasting environmental regimes experienced in central-southern Chile. Our field data indicates that in both study locations, parasitized mussels evidenced higher body sizes (shell length, total weight and volume) as compared with non-parasitized. In addition, parasitized mussels from the southern location evidenced thinner shells than non-parasitized ones and those collected from central Chile, suggesting geographical variation in shell carbonate precipitation across intertidal habitats of the Chilean coast. In laboratory conditions, mussels collected from a local population in central Chile were exposed to two temperature treatments (12 and 18 °C). Parasitized mussels showed higher growth rates than non-parasitized, regardless of the seawater temperature treatments. However, the metabolic rate was not influenced by the parasite condition or the temperature treatments. Our field and laboratory results support the parasite-induced gigantism hypothesis, and suggest that both the thermal environment and geographic location explain only a portion of the increased body size, while the parasitic condition is the most plausible factor modulating the outcome of this host-parasite interaction.
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Affiliation(s)
- M.R. García-Huidobro
- Centro de Investigación e Innovación para el Cambio Climático (CiiCC), Facultad de Ciencias, Universidad Santo Tomás, Ejército 146, Santiago, Chile
- Programa de Doctorado en Conservación y Gestión de la Biodiversidad, Facultad de Ciencias, Universidad Santo Tomás, Ejército 146, Santiago, Chile
| | - O. Varas
- Departamento de Ecología y Biodiversidad, Facultad de Ciencias de la Vida, Universidad Andres Bello, República 440, Santiago, Chile
| | - M. George-Nascimento
- Departamento de Ecología, Facultad de Ciencias, Universidad Católica de la Santísima Concepción, Casilla 297, Concepción, Chile
| | - J. Pulgar
- Departamento de Ecología y Biodiversidad, Facultad de Ciencias de la Vida, Universidad Andres Bello, República 440, Santiago, Chile
| | - M. Aldana
- Centro de Investigación e Innovación para el Cambio Climático (CiiCC), Facultad de Ciencias, Universidad Santo Tomás, Ejército 146, Santiago, Chile
- Programa de Doctorado en Conservación y Gestión de la Biodiversidad, Facultad de Ciencias, Universidad Santo Tomás, Ejército 146, Santiago, Chile
| | - M.A. Lardies
- Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Santiago, Chile
| | - N.A. Lagos
- Centro de Investigación e Innovación para el Cambio Climático (CiiCC), Facultad de Ciencias, Universidad Santo Tomás, Ejército 146, Santiago, Chile
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27
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Sato T, Iritani R, Sakura M. Host manipulation by parasites as a cryptic driver of energy flow through food webs. CURRENT OPINION IN INSECT SCIENCE 2019; 33:69-76. [PMID: 31358198 DOI: 10.1016/j.cois.2019.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 02/25/2019] [Accepted: 02/27/2019] [Indexed: 06/10/2023]
Abstract
Manipulative parasites alter predator-prey interactions, and thus may facilitate, shift or create energy flow pathways through food webs (referred to hereafter as manipulation-mediated energy flow, MMEF). The ecological significance of MMEF would be determined not only by the strength of host manipulation, but also ecological and epidemiological factors, including host biomass, parasite incidence, and trophic position of the host-parasite association in their food webs. While previous theory has predicted that strong manipulation will destabilize host-parasite dynamics, a recently proposed theoretical framework claims that a switching strategy (sequential manipulation from predation suppression to enhancement) should allow parasites to induce strong predation enhancement and thus large MMEF. We formally outline the current and future directions to better understand the causes and consequences of MMEF across biological hierarchies.
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Affiliation(s)
- Takuya Sato
- Department of Biology, Graduate School of Sciences, Kobe University, Japan.
| | - Ryosuke Iritani
- Biosciences, College of Life and Environmental Science, University of Exeter, Cornwall Campus, Penryn, Cornwall TR10 9EZ, United Kingdom; Department of Integrative Biology, University of California, Berkeley, CA 94720, United States
| | - Midori Sakura
- Department of Biology, Graduate School of Sciences, Kobe University, Japan
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Ben-Ami F. Host Age Effects in Invertebrates: Epidemiological, Ecological, and Evolutionary Implications. Trends Parasitol 2019; 35:466-480. [PMID: 31003758 DOI: 10.1016/j.pt.2019.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 12/26/2022]
Abstract
In most species, variation in age among individuals is the strongest and most visible form of phenotypic variation. Individual-level age effects on disease traits, caused by differences in the age at exposure of the host or its parents, have been widely documented in invertebrates. They can influence diverse traits, such as host susceptibility, virulence, parasite reproduction and further transmission, and may cascade to the population level, influencing disease prevalence and within-host competition. Here, I summarize what is known about the relationship between individual-level age/stage effects and infectious disease in invertebrates. I also attempt to link age effects to the theory of aging (senescence), and highlight the importance of population age structure to disease epidemiology and evolution. I conclude by identifying gaps in our understanding of individual- and population-level age effects in invertebrates. As the age structure of populations varies across space and time, age effects have strong epidemiological, ecological, and evolutionary implications for explaining variation in infectious diseases of invertebrates.
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Affiliation(s)
- Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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Savola E, Ebert D. Assessment of parasite virulence in a natural population of a planktonic crustacean. BMC Ecol 2019; 19:14. [PMID: 30871516 PMCID: PMC6419459 DOI: 10.1186/s12898-019-0230-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/28/2019] [Indexed: 02/05/2023] Open
Abstract
Background Understanding the impact of disease in natural populations requires an understanding of infection risk and the damage that parasites cause to their hosts (= virulence). However, because these disease traits are often studied and quantified under controlled laboratory conditions and with reference to healthy control hosts, we have little knowledge about how they play out in natural conditions. In the Daphnia–Pasteuria host–parasite system, field assessments often show very low estimates of virulence, while controlled laboratory experiments indicate extremely high virulence. Results To examine this discrepancy, we sampled Daphnia magna hosts from the field during a parasite epidemic and recorded disease traits over a subsequent 3-week period in the laboratory. As predicted for chronic disease where infections in older (larger) hosts are also, on average, older, we found that larger D. magna females were infected more often, had fewer offspring prior to the onset of castration and showed signs of infection sooner than smaller hosts. Also consistent with laboratory experiments, infected animals were found in both sexes and in all sizes of hosts. Infected females were castrated at capture or became castrated soon after. As most females in the field carried no eggs in their brood pouch at the time of sampling, virulence estimates of infected females relative to uninfected females were low. However, with improved feeding conditions in the laboratory, only uninfected females resumed reproduction, resulting in very high relative virulence estimates. Conclusions Overall, our study shows that the disease manifestation of P. ramosa, as expressed under natural conditions, is consistent with what we know from laboratory experiments. However, parasite induced fecundity reduction of infected, relative to uninfected hosts depended strongly on the environmental conditions. We argue that this effect is particularly strong for castrating parasites, because infected hosts have low fecundity under all conditions.
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Affiliation(s)
- Eevi Savola
- Department of Environmental Sciences, Zoology, Basel University, Vesalgasse 1, 4051, Basel, Switzerland.,Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Ashworth Laboratories, Edinburgh, EH9 3FL, UK
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, Basel University, Vesalgasse 1, 4051, Basel, Switzerland.
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Schlüter-Vorberg L, Coors A. Impact of an immunosuppressive human pharmaceutical on the interaction of a bacterial parasite and its invertebrate host. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 206:91-101. [PMID: 30468978 DOI: 10.1016/j.aquatox.2018.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/07/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
The interaction of pollutants and pathogens may result in altered and often enhanced effects of the chemical, the biotic stressor or both. These interaction effects cannot be reliably predicted from the toxicity of the chemical or the virulence of the pathogen alone. While standardized detection methods for immunotoxic effects of chemicals exist with regard to human health, employing host-resistance assays with vertebrates, such standardized test systems are completely lacking for invertebrate species and no guidance is available on how immunotoxic effects of a chemical in invertebrates could be definitively identified. In the present study, we investigated the impact of the immunosuppressive pharmaceutical cyclosporine A (CsA) on the invertebrate host-pathogen system Daphnia magna - Pasteuria ramosa. CsA is a calcineurin-inhibitor in vertebrates and also known to have antibiotic as well as antifungal properties. Juvenile D. magna were exposed to CsA for 21 days with or without additional pathogen challenge during the first 72 h of exposure. Long-term survival of the host D. magna was synergistically impacted by co-exposure to the chemical and the pathogen, expressed e.g. in significantly enhanced hazard ratios. Additionally, enhanced virulence of the pathogen upon chemical co-exposure was expressed in an increased proportion of infected hosts and an increased speed of Pasteuria-induced host sterilization. In contrast, effects on reproduction were additive in Pasteuria-challenged, but finally non-infected D. magna. The enhancing effects of CsA occurred at and below 3 μg/L, which was in the absence of the pathogen the lowest concentration significantly impacting the standard toxicity endpoint 'reproduction' in D. magna. Hence, the present study provides evidence that a pharmaceutical intended to suppress the human immune system can also suppress disease resistance of an aquatic invertebrate organism at otherwise non-toxic concentrations. Plausible ways of direct interactions of CsA with the host's immune system are discussed, e.g. interference with phagocytosis or Toll-like receptors. Experimental verification of such a direct interference would be warranted to support the strong evidence for immunotoxic activity of CsA in invertebrates. While it remains open whether CsA concentrations in the environment are high enough to trigger adverse effects in environmental organisms, our findings highlight the need to consider immunotoxicity in an environmental risk assessment, and to develop suitable standardized methods for this purpose.
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Affiliation(s)
- Lisa Schlüter-Vorberg
- ECT Oekotoxikologie GmbH, Flörsheim/Main, Germany; Goethe-University Frankfurt am Main, Department Aquatic Ecotoxicology, Frankfurt am Main, Germany.
| | - Anja Coors
- ECT Oekotoxikologie GmbH, Flörsheim/Main, Germany
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Tian-Bi YNT, Konan JNK, Sangaré A, Ortega-Abboud E, Utzinger J, N'Goran EK, Jarne P. Spatio-temporal population genetic structure, relative to demographic and ecological characteristics, in the freshwater snail Biomphalaria pfeifferi in Man, western Côte d'Ivoire. Genetica 2018; 147:33-45. [PMID: 30498954 DOI: 10.1007/s10709-018-0049-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 11/22/2018] [Indexed: 11/30/2022]
Abstract
Combining the analysis of spatial and temporal variation when investigating population structure enhances our capacity for unravelling the biotic and abiotic factors responsible for microevolutionary change. This work aimed at measuring the spatial and temporal genetic structure of populations of the freshwater snail Biomphalaria pfeifferi (the intermediate host of the trematode Schistosoma mansoni) in relation to the mating system (self-fertilization), demography, parasite prevalence and some ecological parameters. Snail populations were sampled four times in seven human-water contact sites in the Man region, western Côte d'Ivoire, and their variability was measured at five microsatellite loci. Limited genetic diversity and high selfing rates were observed in the populations studied. We failed to reveal an effect of demographic and ecological parameters on within-population diversity, perhaps as a result of a too small number of populations. A strong spatial genetic differentiation was detected among populations. The temporal differentiation within populations was high in most populations, though lower than the spatial differentiation. All estimates of effective population size were lower than seven suggesting a strong effect of genetic drift. However, the genetic drift was compensated by high gene flow. The genetic structure within and among populations reflected that observed in other selfing snail species, relying on high selfing rates, low effective population sizes, environmental stochasticity and high gene flow.
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Affiliation(s)
- Yves-Nathan T Tian-Bi
- Laboratoire de Génétique, Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 1106, Abidjan 22, Côte d'Ivoire.
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire.
| | - Jean-Noël K Konan
- Centre National de Recherche Agronomique, Adiopodoumé KM 17, route de Dabou, 01 BP 1740, Abidjan 01, Côte d'Ivoire
| | - Abdourahamane Sangaré
- Centre National de Recherche Agronomique, Adiopodoumé KM 17, route de Dabou, 01 BP 1740, Abidjan 01, Côte d'Ivoire
| | - Enrique Ortega-Abboud
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, IRD, Université de Montpellier, Université Paul Valéry Montpellier, EPHE, 1919 route de Mende, 34293, Montpellier Cedex 5, France
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, P.O. Box, 4002, Basel, Switzerland
- University of Basel, P.O. Box, 4003, Basel, Switzerland
| | - Eliézer K N'Goran
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire
- Laboratoire de Zoologie-Biologie Animale, Unité de Recherche et de Formation Parasitologie et Ecologie Parasitaire, Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 582, Abidjan 22, Côte d'Ivoire
| | - Philippe Jarne
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, IRD, Université de Montpellier, Université Paul Valéry Montpellier, EPHE, 1919 route de Mende, 34293, Montpellier Cedex 5, France
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Reyserhove L, Samaey G, Muylaert K, Coppé V, Van Colen W, Decaestecker E. A historical perspective of nutrient change impact on an infectious disease in Daphnia. Ecology 2018; 98:2784-2798. [PMID: 28845593 DOI: 10.1002/ecy.1994] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/18/2017] [Accepted: 07/10/2017] [Indexed: 01/01/2023]
Abstract
Changes in food quality can play a substantial role in the vulnerability of hosts to infectious diseases. In this study, we focused on the genetic differentiation of the water flea Daphnia magna towards food of different quality (by manipulating C:N:P ratios) and its impact on the interaction with a virulent infectious disease, "White Fat Cell Disease (WFCD)". Via a resurrection ecology approach, we isolated two Daphnia subpopulations from different depths in a sediment core, which were exposed to parasites and a nutrient ratio gradient in a common garden experiment. Our results showed a genetic basis for sensitivity towards food deprivation. Both fecundity and host survival was differently affected when fed with low-quality food. This strongly impacted the way both subpopulations interacted with this parasite. A historical reconstruction of nutrient changes in a sediment core reflected an increase in organic material and phosphorus concentration (more eutrophic conditions) over time in the studied pond. These results enable us to relate patterns of genetic differentiation in sensitivity towards food deprivation to an increasing level of eutrophication of the subpopulations, which ultimately impacts parasite virulence effects. This finding was confirmed via a dynamic energy budgets (DEB), in which energy was partitioned for the host and the parasite. The model was tailored to our study by integrating (1) increased growth and a fecundity shift in the host upon parasitism and (2) differences of food assimilation in the subpopulations showing that a reduced nutrient assimilation resulted in increased parasite virulence. The combination of our experiment with the DEB model shows that it is important to consider genetic diversity when studying the impact of nutritional stress on species interactions, especially in the context of changing environments and emerging infectious diseases.
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Affiliation(s)
- Lien Reyserhove
- KU Leuven, Interdisciplinary Research Facility Life Sciences, KULAK, Campus Kortrijk, Etienne Sabbelaan 53, Kortrijk, B-8500, Belgium
| | - Giovanni Samaey
- Department of Computer Science, KU Leuven, Celestijnenlaan 200A, Leuven, B-3001, Belgium
| | - Koenraad Muylaert
- KU Leuven, Interdisciplinary Research Facility Life Sciences, KULAK, Campus Kortrijk, Etienne Sabbelaan 53, Kortrijk, B-8500, Belgium
| | - Vincent Coppé
- Department of Computer Science, KU Leuven, Celestijnenlaan 200A, Leuven, B-3001, Belgium
| | - Willem Van Colen
- KU Leuven, Interdisciplinary Research Facility Life Sciences, KULAK, Campus Kortrijk, Etienne Sabbelaan 53, Kortrijk, B-8500, Belgium
| | - Ellen Decaestecker
- KU Leuven, Interdisciplinary Research Facility Life Sciences, KULAK, Campus Kortrijk, Etienne Sabbelaan 53, Kortrijk, B-8500, Belgium
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Anzia EL, Rabajante JF. Antibiotic-driven escape of host in a parasite-induced Red Queen dynamics. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180693. [PMID: 30839730 PMCID: PMC6170573 DOI: 10.1098/rsos.180693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/14/2018] [Indexed: 06/09/2023]
Abstract
Winnerless coevolution of hosts and parasites could exhibit Red Queen dynamics, which is characterized by parasite-driven cyclic switching of expressed host phenotypes. We hypothesize that the application of antibiotics to suppress the reproduction of parasites can provide an opportunity for the hosts to escape such winnerless coevolution. Here, we formulate a minimal mathematical model of host-parasite interaction involving multiple host phenotypes that are targeted by adapting parasites. Our model predicts the levels of antibiotic effectiveness that can steer the parasite-driven cyclic switching of host phenotypes (oscillations) to a stable equilibrium of host survival. Our simulations show that uninterrupted application of antibiotic with high-level effectiveness (greater than 85%) is needed to escape the Red Queen dynamics. Interrupted and low level of antibiotic effectiveness are indeed useless to stop host-parasite coevolution. This study can be a guide in designing good practices and protocols to minimize the risk of further progression of parasitic infections.
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Affiliation(s)
| | - Jomar F. Rabajante
- Institute of Mathematical Sciences and Physics, University of the Philippines Los Baños, Laguna, Philippines
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Auld SKJR, Tinkler SK, Tinsley MC. Sex as a strategy against rapidly evolving parasites. Proc Biol Sci 2017; 283:rspb.2016.2226. [PMID: 28003455 PMCID: PMC5204169 DOI: 10.1098/rspb.2016.2226] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/18/2016] [Indexed: 11/20/2022] Open
Abstract
Why is sex ubiquitous when asexual reproduction is much less costly? Sex disrupts coadapted gene complexes; it also causes costs associated with mate finding and the production of males who do not themselves bear offspring. Theory predicts parasites select for host sex, because genetically variable offspring can escape infection from parasites adapted to infect the previous generations. We examine this using a facultative sexual crustacean, Daphnia magna, and its sterilizing bacterial parasite, Pasteuria ramosa. We obtained sexually and asexually produced offspring from wild-caught hosts and exposed them to contemporary parasites or parasites isolated from the same population one year later. We found rapid parasite adaptation to replicate within asexual but not sexual offspring. Moreover, sexually produced offspring were twice as resistant to infection as asexuals when exposed to parasites that had coevolved alongside their parents (i.e. the year two parasite). This fulfils the requirement that the benefits of sex must be both large and rapid for sex to be favoured by selection.
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Affiliation(s)
- Stuart K J R Auld
- Division of Biological and Environmental Sciences, University of Stirling, Room 3B164, Cottrell Building, Stirling, Stirlingshire FK9 4LA, UK
| | - Shona K Tinkler
- Division of Biological and Environmental Sciences, University of Stirling, Room 3B164, Cottrell Building, Stirling, Stirlingshire FK9 4LA, UK
| | - Matthew C Tinsley
- Division of Biological and Environmental Sciences, University of Stirling, Room 3B164, Cottrell Building, Stirling, Stirlingshire FK9 4LA, UK
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36
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Ben‐Ami F. The virulence-transmission relationship in an obligate killer holds under diverse epidemiological and ecological conditions, but where is the tradeoff? Ecol Evol 2017; 7:11157-11166. [PMID: 29299290 PMCID: PMC5743645 DOI: 10.1002/ece3.3532] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/30/2017] [Accepted: 09/13/2017] [Indexed: 01/07/2023] Open
Abstract
Parasite virulence is a leading theme in evolutionary biology. Modeling the course of virulence evolution holds the promise of providing practical insights into the management of infectious diseases and the implementation of vaccination strategies. A key element of virulence modeling is a tradeoff between parasite transmission rate and host lifespan. This assumption is crucial for predicting the level of optimal virulence. Here, I test this assumption using the water flea Daphnia magna and its castrating and obligate-killing bacterium Pasteuria ramosa. I found that the virulence-transmission relationship holds under diverse epidemiological and ecological conditions. In particular, parasite genotype, absolute and relative parasite dose, and within-host competition in multiple infections did not significantly affect the observed trend. Interestingly, the relationship between virulence and parasite transmission in this system is best explained by a model that includes a cubic term. Under this relationship, parasite transmission initially peaks and saturates at an intermediate level of virulence, but then it further increases as virulence decreases, surpassing the previous peak. My findings also highlight the problem of using parasite-induced host mortality as a "one-size-fits-all" measure of virulence for horizontally transmitted parasites, without considering the onset and duration of parasite transmission as well as other equally virulent effects of parasites (e.g., host castration). Therefore, mathematical models may be required to predict whether these particular characteristics of horizontally transmitted parasites can direct virulence evolution into directions not envisaged by existing models.
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Affiliation(s)
- Frida Ben‐Ami
- School of ZoologyGeorge S. Wise Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
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Vijayan V, López-González S, Sánchez F, Ponz F, Pagán I. Virulence evolution of a sterilizing plant virus: Tuning multiplication and resource exploitation. Virus Evol 2017; 3:vex033. [PMID: 29250431 PMCID: PMC5724401 DOI: 10.1093/ve/vex033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Virulence evolution may have far-reaching consequences for virus epidemiology and emergence, and virologists have devoted increasing effort to understand the modulators of this process. However, still little is known on the mechanisms and determinants of virulence evolution in sterilizing viruses that, as they prevent host reproduction, may have devastating effects on host populations. Theory predicts that sterilizing parasites, including viruses, would evolve towards lower virulence and absolute host sterilization to optimize the exploitation of host resources and maximize fitness. However, this hypothesis has seldom been analyzed experimentally. We investigated the evolution of virulence of the sterilizing plant virus Turnip mosaic virus (TuMV) in its natural host Arabidopsis thaliana by serial passage experiments. After passaging, we quantified virus accumulation and infectivity, the effect of infection on plant growth and development, and virulence of the ancestral and passaged viral genotypes in A. thaliana. Results indicated that serial passaging increased the proportion of infected plants showing absolute sterility, reduced TuMV virulence, and increased virus multiplication and infectivity. Genomic comparison of the ancestral and passaged TuMV genotypes identified significant mutation clustering in the P1, P3, and 6K2 proteins, suggesting a role of these viral proteins in the observed phenotypic changes. Our results support theoretical predictions on the evolution of virulence of sterilizing parasites and contribute to better understand the phenotypic and genetic changes associated with this process.
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Affiliation(s)
- Viji Vijayan
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Autopista M-40, km 38, Campus Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Silvia López-González
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Autopista M-40, km 38, Campus Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Flora Sánchez
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Autopista M-40, km 38, Campus Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Fernando Ponz
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Autopista M-40, km 38, Campus Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Autopista M-40, km 38, Campus Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain
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Auld SKJR, Brand J. Environmental variation causes different (co) evolutionary routes to the same adaptive destination across parasite populations. Evol Lett 2017; 1:245-254. [PMID: 30283653 PMCID: PMC6121849 DOI: 10.1002/evl3.27] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/15/2017] [Indexed: 11/13/2022] Open
Abstract
Epidemics are engines for host-parasite coevolution, where parasite adaptation to hosts drives reciprocal adaptation in host populations. A key challenge is to understand whether parasite adaptation and any underlying evolution and coevolution is repeatable across ecologically realistic populations that experience different environmental conditions, or if each population follows a completely unique evolutionary path. We established twenty replicate pond populations comprising an identical suite of genotypes of crustacean host, Daphnia magna, and inoculum of their parasite, Pasteuria ramosa. Using a time-shift experiment, we compared parasite infection traits before and after epidemics and linked patterns of parasite evolution with shifts in host genotype frequencies. Parasite adaptation to the sympatric suite of host genotypes came at a cost of poorer performance on foreign genotypes across populations and environments. However, this consistent pattern of parasite adaptation was driven by different types of frequency-dependent selection that was contingent on an ecologically relevant environmental treatment (whether or not there was physical mixing of water within ponds). In unmixed ponds, large epidemics drove rapid and strong host-parasite coevolution. In mixed ponds, epidemics were smaller and host evolution was driven mainly by the mixing treatment itself; here, host evolution and parasite evolution were clear, but coevolution was absent. Population mixing breaks an otherwise robust coevolutionary cycle. These findings advance our understanding of the repeatability of (co)evolution across noisy, ecologically realistic populations.
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Affiliation(s)
- Stuart K. J. R. Auld
- Biological and Environmental SciencesUniversity of StirlingStirlingUnited Kingdom
| | - June Brand
- Biological and Environmental SciencesUniversity of StirlingStirlingUnited Kingdom
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Sandland GJ, Josephson KA. Nutrient availability modulates both host and parasite life histories in a snail-trematode interaction. DISEASES OF AQUATIC ORGANISMS 2017; 126:135-142. [PMID: 29044043 DOI: 10.3354/dao03169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Host nutrient availability can have important life history consequences for hosts and their parasites. The responses of each participant within the association can vary extensively across host-parasite systems. In this paper, we outline the life history responses of the aquatic snail Biomphalaria glabrata and its trematode parasite Echinostoma caproni during host nutrient restriction. The onset of host starvation had rapid and strong effects on snail reproduction, significantly reducing egg output in control snails and eliminating egg production in infected individuals. The combination of E. caproni infection and nutrient restriction also had a dramatic effect on B. glabrata survival, with starved infected snails dying at a faster rate than hosts from any other treatment. In terms of parasite reproduction, host nutrient restriction did not influence the quantity of parasite larvae produced after starvation onset but did influence parasite quality, reducing both larval swimming time and overall longevity. Together these results demonstrate that nutrient restriction can strongly influence both host and parasite life histories, and therefore should be considered in future studies attempting to understand patterns of disease in host populations.
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Affiliation(s)
- Gregory J Sandland
- Department of Biology, University of Wisconsin-La Crosse, 1725 State Street, La Crosse, WI 54601, USA
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Chodkowski N, Bernot RJ. Parasite and host elemental content and parasite effects on host nutrient excretion and metabolic rate. Ecol Evol 2017; 7:5901-5908. [PMID: 28808553 PMCID: PMC5551083 DOI: 10.1002/ece3.3129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 11/10/2022] Open
Abstract
Ecological stoichiometry uses the mass balance of elements to predict energy and elemental fluxes across different levels of ecological organization. A specific prediction of ecological stoichiometry is the growth rate hypothesis (GRH), which states that organisms with faster growth or reproductive rates will require higher phosphorus content for nucleic acid and protein synthesis. Although parasites are found ubiquitously throughout ecosystems, little is understood about how they affect nutrient imbalances in ecosystems. We (1) tested the GRH by determining the carbon (C), nitrogen (N), and phosphorus (P) content of parasitic trematodes and their intermediate host, the freshwater snail Elimia livescens, and (2) used this framework to determine the trematode effects on host nutrient excretion and metabolism. Snail and parasite tissues were analyzed for elemental content using a CHN analyzer and soluble reactive phosphorus (SRP) methods. Ammonium and SRP assays were used to estimate N and P excretion rates. A respirometer was used to calculate individual snail metabolism. Trematode tissues contained lower C:P and N:P (more P per unit C and N) than the snail tissues. Snail gonadal tissues more closely resembled the elemental content of parasite tissues, although P content was 13% higher in the gonad than the trematode tissues. Despite differences in elemental content, N and P excretion rates of snails were not affected by the presence of parasites. Parasitized snails maintained faster metabolic rates than nonparasitized snails. However, the species of parasite did not affect metabolic rate. Together, this elemental imbalance between parasite and host, and the altered metabolic rate of infected snails may lead to broader parasite effects in stream ecosystems.
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Sarcoptes scabiei alters follicular dynamics in female Iberian ibex through a reduction in body weight. Vet Parasitol 2017; 243:151-156. [PMID: 28807285 DOI: 10.1016/j.vetpar.2017.06.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/22/2017] [Accepted: 06/24/2017] [Indexed: 11/24/2022]
Abstract
Normal development of the ovarian cycle is a key factor in ensuring female reproductive success. Sarcoptes scabiei has been shown to induce changes in host physiology, although the effects of this mite on the female reproductive cycle are still unknown. In an attempt to clarify this issue, the number of ovarian structures (primary follicles, secondary follicles, Graaf follicles, corpus luteum and corpus albicans) in female Iberian ibex (Capra pyrenaica) affected by sarcoptic mange was explored by histological analysis of samples taken from 102 females selectively harvested in the Sierra Nevada Natural Space, southern Spain. The effect of mange status, body weight (corrected for age), age and year of sampling on the number of ovarian structures was assessed using generalized linear models. Our results provide evidence that sarcoptic mange alters follicular dynamics through a reduction in host body weight, whose main consequences are noted in follicular maturation and ovulatory capacity.
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42
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Franke F, Armitage SAO, Kutzer MAM, Kurtz J, Scharsack JP. Environmental temperature variation influences fitness trade-offs and tolerance in a fish-tapeworm association. Parasit Vectors 2017; 10:252. [PMID: 28571568 PMCID: PMC5455083 DOI: 10.1186/s13071-017-2192-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/11/2017] [Indexed: 11/29/2022] Open
Abstract
Background Increasing temperatures are predicted to strongly impact host-parasite interactions, but empirical tests are rare. Host species that are naturally exposed to a broad temperature spectrum offer the possibility to investigate the effects of elevated temperatures on hosts and parasites. Using three-spined sticklebacks, Gasterosteus aculeatus L., and tapeworms, Schistocephalus solidus (Müller, 1776), originating from a cold and a warm water site of a volcanic lake, we subjected sympatric and allopatric host-parasite combinations to cold and warm conditions in a fully crossed design. We predicted that warm temperatures would promote the development of the parasites, while the hosts might benefit from cooler temperatures. We further expected adaptations to the local temperature and mutual adaptations of local host-parasite pairs. Results Overall, S. solidus parasites grew faster at warm temperatures and stickleback hosts at cold temperatures. On a finer scale, we observed that parasites were able to exploit their hosts more efficiently at the parasite’s temperature of origin. In contrast, host tolerance towards parasite infection was higher when sticklebacks were infected with parasites at the parasite’s ‘foreign’ temperature. Cold-origin sticklebacks tended to grow faster and parasite infection induced a stronger immune response. Conclusions Our results suggest that increasing environmental temperatures promote the parasite rather than the host and that host tolerance is dependent on the interaction between parasite infection and temperature. Sticklebacks might use tolerance mechanisms towards parasite infection in combination with their high plasticity towards temperature changes to cope with increasing parasite infection pressures and rising temperatures. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2192-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Frederik Franke
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149, Münster, Germany
| | - Sophie A O Armitage
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149, Münster, Germany
| | - Megan A M Kutzer
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149, Münster, Germany
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149, Münster, Germany
| | - Jörn P Scharsack
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149, Münster, Germany.
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Million KM, Tarver CL, Hipe S, Stallsmith BW. Does Infection by the Monogenoidean Gill Parasite Aethycteron mooreiAffect Reproductive Ecology of the Darter Etheostoma flabellarein Mill Creek, Tennessee? COPEIA 2017. [DOI: 10.1643/ce-16-403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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44
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Seasonal distribution of the invasive snail, Bithynia tentaculata, within infested waterbodies in Minnesota, USA, including waterfowl migration. Biol Invasions 2016. [DOI: 10.1007/s10530-016-1183-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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45
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Vogt G. Structural specialties, curiosities, and record-breaking features of crustacean reproduction. J Morphol 2016; 277:1399-1422. [DOI: 10.1002/jmor.20582] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/18/2016] [Accepted: 07/06/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Günter Vogt
- Faculty of Biosciences; University of Heidelberg; Im Neuenheimer Feld 230 69120 Heidelberg Germany
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46
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Rabajante JF, Tubay JM, Ito H, Uehara T, Kakishima S, Morita S, Yoshimura J, Ebert D. Host-parasite Red Queen dynamics with phase-locked rare genotypes. SCIENCE ADVANCES 2016; 2:e1501548. [PMID: 26973878 PMCID: PMC4783124 DOI: 10.1126/sciadv.1501548] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 01/08/2016] [Indexed: 06/05/2023]
Abstract
Interactions between hosts and parasites have been hypothesized to cause winnerless coevolution, called Red Queen dynamics. The canonical Red Queen dynamics assume that all interacting genotypes of hosts and parasites undergo cyclic changes in abundance through negative frequency-dependent selection, which means that any genotype could become frequent at some stage. However, this prediction cannot explain why many rare genotypes stay rare in natural host-parasite systems. To investigate this, we build a mathematical model involving multihost and multiparasite genotypes. In a deterministic and controlled environment, Red Queen dynamics occur between two genotypes undergoing cyclic dominance changes, whereas the rest of the genotypes remain subordinate for long periods of time in phase-locked synchronized dynamics with low amplitude. However, introduction of stochastic noise in the model might allow the subordinate cyclic host and parasite types to replace dominant cyclic types as new players in the Red Queen dynamics. The factors that influence such evolutionary switching are interhost competition, specificity of parasitism, and degree of stochastic noise. Our model can explain, for the first time, the persistence of rare, hardly cycling genotypes in populations (for example, marine microbial communities) undergoing host-parasite coevolution.
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Affiliation(s)
- Jomar F. Rabajante
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
- Mathematics Division, Institute of Mathematical Sciences and Physics, University of the Philippines Los Baños, College, Laguna 4031, Philippines
| | - Jerrold M. Tubay
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
- Mathematics Division, Institute of Mathematical Sciences and Physics, University of the Philippines Los Baños, College, Laguna 4031, Philippines
| | - Hiromu Ito
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
| | - Takashi Uehara
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
- Department of Preschool Education, Nagoya College, Toyoake, Aichi 470-1193, Japan
| | - Satoshi Kakishima
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
| | - Satoru Morita
- Department of Mathematical and Systems Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
| | - Jin Yoshimura
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
- Department of Mathematical and Systems Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
- Marine Biosystems Research Center, Chiba University, Uchiura, Kamogawa, Chiba 299-5502, Japan
- Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Dieter Ebert
- Zoological Institute, University of Basel, Vesalgasse 1, Basel 4051, Switzerland
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Abstract
Virulence is generally defined as the reduction in host fitness following infection by a parasite (see Box 1 for glossary) [1]. In general, parasite exploitation of host resources may reduce host survival (mortality virulence), decrease host fecundity (sterility virulence), or even have sub-lethal effects that disturb the way individuals interact within a community (morbidity) [2,3]. In fact, the virulence of many parasites involves a combination of these various effects (Box 2). In practice, however, virulence is most often defined as disease-induced mortality [1, 4–6]. This is especially true in the theoretical literature, where the evolution of sterility virulence, morbidity, and mixed strategies of host exploitation have received relatively little attention. While the focus on mortality effects has allowed for easy comparison between models and, thus, rapid advancement of the field, we ask whether these theoretical simplifications have led us to inadvertently minimize the evolutionary importance of host sterilization and secondary virulence effects. As explicit theoretical work on morbidity is currently lacking (but see [7]), our aim in this Opinion piece is to discuss what is understood about sterility virulence evolution, its adaptive potential, and the implications for parasites that utilize a combination of host survival and reproductive resources.
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Affiliation(s)
- Jessica L. Abbate
- Centre d’Écologie Fonctionnelle et Évolutive (CEFE), CNRS-Université de Montpellier- Université Paul-Valéry Montpellier-EPHE, Montpellier, France
- Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
- * E-mail:
| | - Sarah Kada
- Centre d’Écologie Fonctionnelle et Évolutive (CEFE), CNRS-Université de Montpellier- Université Paul-Valéry Montpellier-EPHE, Montpellier, France
| | - Sébastien Lion
- Centre d’Écologie Fonctionnelle et Évolutive (CEFE), CNRS-Université de Montpellier- Université Paul-Valéry Montpellier-EPHE, Montpellier, France
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Ebert D, Duneau D, Hall MD, Luijckx P, Andras JP, Du Pasquier L, Ben-Ami F. A Population Biology Perspective on the Stepwise Infection Process of the Bacterial Pathogen Pasteuria ramosa in Daphnia. ADVANCES IN PARASITOLOGY 2015; 91:265-310. [PMID: 27015951 DOI: 10.1016/bs.apar.2015.10.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The infection process of many diseases can be divided into series of steps, each one required to successfully complete the parasite's life and transmission cycle. This approach often reveals that the complex phenomenon of infection is composed of a series of more simple mechanisms. Here we demonstrate that a population biology approach, which takes into consideration the natural genetic and environmental variation at each step, can greatly aid our understanding of the evolutionary processes shaping disease traits. We focus in this review on the biology of the bacterial parasite Pasteuria ramosa and its aquatic crustacean host Daphnia, a model system for the evolutionary ecology of infectious disease. Our analysis reveals tremendous differences in the degree to which the environment, host genetics, parasite genetics and their interactions contribute to the expression of disease traits at each of seven different steps. This allows us to predict which steps may respond most readily to selection and which steps are evolutionarily constrained by an absence of variation. We show that the ability of Pasteuria to attach to the host's cuticle (attachment step) stands out as being strongly influenced by the interaction of host and parasite genotypes, but not by environmental factors, making it the prime candidate for coevolutionary interactions. Furthermore, the stepwise approach helps us understanding the evolution of resistance, virulence and host ranges. The population biological approach introduced here is a versatile tool that can be easily transferred to other systems of infectious disease.
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Affiliation(s)
- Dieter Ebert
- Zoological Institute, University of Basel, Basel, Switzerland
| | - David Duneau
- Zoological Institute, University of Basel, Basel, Switzerland; Department Ecologie et Diversité Biologique, University Paul Sabatier-Toulouse III, Toulouse, France
| | - Matthew D Hall
- Zoological Institute, University of Basel, Basel, Switzerland; Monash University, School of Biological Sciences, Clayton Campus, Melbourne, VIC, Australia
| | - Pepijn Luijckx
- Zoological Institute, University of Basel, Basel, Switzerland; Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Jason P Andras
- Zoological Institute, University of Basel, Basel, Switzerland; Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
| | | | - Frida Ben-Ami
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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49
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Tavalire HF, Blouin MS, Steinauer ML. Genotypic variation in host response to infection affects parasite reproductive rate. Int J Parasitol 2015; 46:123-31. [PMID: 26552016 DOI: 10.1016/j.ijpara.2015.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/15/2015] [Accepted: 10/15/2015] [Indexed: 12/20/2022]
Abstract
Parasite fitness is largely influenced by a variation in host response due to the host's genetic background. Here we investigated the impact of host genotype on pathogen success in the snail vector of its castrating parasite, Schistosoma mansoni. We infected five inbred lines of Biomphalaria glabrata with two infection doses and followed their growth, reproductive output and parasite production throughout the course of infection. There was no difference in resistance to infection among inbred lines, but lines varied in their responses to infection and the numbers of parasites produced. Snails did not compensate for castration by increasing their fecundity during the early phase of infection (fecundity compensation). However, some lines were able to delay parasite shedding for up to 30 weeks, thus prolonging reproduction before the onset of castration. Here we propose this strategy as a novel defense against castrating pathogens in snails. Gigantism, a predicted outcome of castration due to energy reallocation, occurred early in infection (<15 weeks) and was not universal among the snail lines. Lines that did not show gigantism were also characterised by a high parasite production rate and low survivorship, perhaps indicating energy reallocation into parasite production and costly immune defense. We observed no differences in total parasite production among lines throughout the entire course of infection, although lines differed in their parasite reproductive rate. The average rate of parasite production varied among lines from 1300 to 2450 cercariae within a single 2h shedding period, resulting in a total production of 6981-29,509 cercariae over the lifetime of a single snail. Regardless of genetic background, snail size was a strong predictor of parasite reproduction: each millimetre increase in snail size at the time of the first shed resulted in up to 3500 more cercariae over the lifetime of the snail. The results of this study provide a detailed picture of variation in hosts' responses to infection and the resulting impacts on parasite fitness, further defining the intricacies of snail-schistosome compatibility.
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Affiliation(s)
- Hannah F Tavalire
- Department of Integrative Biology, 3029 Cordley Hall, Oregon State University, Corvallis, OR 97330, USA.
| | - Michael S Blouin
- Department of Integrative Biology, 3029 Cordley Hall, Oregon State University, Corvallis, OR 97330, USA
| | - Michelle L Steinauer
- Department of Basic Medical Sciences, 200 Mullins Dr., Western University of Health Sciences, COMP-NW, Lebanon, OR 97355, USA
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50
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Clerc M, Ebert D, Hall MD. Expression of parasite genetic variation changes over the course of infection: implications of within-host dynamics for the evolution of virulence. Proc Biol Sci 2015; 282:20142820. [PMID: 25761710 DOI: 10.1098/rspb.2014.2820] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
How infectious disease agents interact with their host changes during the course of infection and can alter the expression of disease-related traits. Yet by measuring parasite life-history traits at one or few moments during infection, studies have overlooked the impact of variable parasite growth trajectories on disease evolution. Here we show that infection-age-specific estimates of host and parasite fitness components can reveal new insight into the evolution of parasites. We do so by characterizing the within-host dynamics over an entire infection period for five genotypes of the castrating bacterial parasite Pasteuria ramosa infecting the crustacean Daphnia magna. Our results reveal that genetic variation for parasite-induced gigantism, host castration and parasite spore loads increases with the age of infection. Driving these patterns appears to be variation in how well the parasite maintains control of host reproduction late in the infection process. We discuss the evolutionary consequences of this finding with regard to natural selection acting on different ages of infection and the mechanism underlying the maintenance of castration efficiency. Our results highlight how elucidating within-host dynamics can shed light on the selective forces that shape infection strategies and the evolution of virulence.
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Affiliation(s)
- Melanie Clerc
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Labs, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK Zoological Institute, University of Basel, Vesalgasse 1, Basel 4051, Switzerland
| | - Dieter Ebert
- Zoological Institute, University of Basel, Vesalgasse 1, Basel 4051, Switzerland
| | - Matthew D Hall
- Zoological Institute, University of Basel, Vesalgasse 1, Basel 4051, Switzerland School of Biological Sciences, Monash University, Melbourne 3800, Australia
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