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Erdos Z, Studholme DJ, Sharma MD, Chandler D, Bass C, Raymond B. Manipulating multi-level selection in a fungal entomopathogen reveals social conflicts and a method for improving biocontrol traits. PLoS Pathog 2024; 20:e1011775. [PMID: 38527086 PMCID: PMC10994555 DOI: 10.1371/journal.ppat.1011775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 04/04/2024] [Accepted: 03/09/2024] [Indexed: 03/27/2024] Open
Abstract
Changes in parasite virulence are commonly expected to lead to trade-offs in other life history traits that can affect fitness. Understanding these trade-offs is particularly important if we want to manipulate the virulence of microbial biological control agents. Theoretically, selection across different spatial scales, i.e. between- and within-hosts, shapes these trade-offs. However, trade-offs are also dependent on parasite biology. Despite their applied importance the evolution of virulence in fungal parasites is poorly understood: virulence can be unstable in culture and commonly fails to increase in simple passage experiments. We hypothesized that manipulating selection intensity at different scales would reveal virulence trade-offs in a fungal pathogen of aphids, Akanthomyces muscarius. Starting with a genetically diverse stock we selected for speed of kill, parasite yield or infectivity by manipulating competition within and between hosts and between-populations of hosts over 7 rounds of infection. We characterized ancestral and evolved lineages by whole genome sequencing and by measuring virulence, growth rate, sporulation and fitness. While several lineages showed increases in virulence, we saw none of the trade-offs commonly found in obligately-killing parasites. Phenotypically similar lineages within treatments often shared multiple single-nucleotide variants, indicating strong convergent evolution. The most dramatic phenotypic changes were in timing of sporulation and spore production in vitro. We found that early sporulation led to reduced competitive fitness but could increase yield of spores on media, a trade-off characteristic of social conflict. Notably, the selection regime with strongest between-population competition and lowest genetic diversity produced the most consistent shift to early sporulation, as predicted by social evolution theory. Multi-level selection therefore revealed social interactions novel to fungi and showed that these biocontrol agents have the genomic flexibility to improve multiple traits-virulence and spore production-that are often in conflict in other parasites.
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Affiliation(s)
- Zoltan Erdos
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | | | - Manmohan D. Sharma
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - David Chandler
- School of Life Sciences, The University of Warwick, Coventry, United Kingdom
| | - Chris Bass
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Ben Raymond
- Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
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Rodríguez-Pastor R, Hasik AZ, Knossow N, Bar-Shira E, Shahar N, Gutiérrez R, Zaman L, Harrus S, Lenski RE, Barrick JE, Hawlena H. Bartonella infections are prevalent in rodents despite efficient immune responses. Parasit Vectors 2023; 16:315. [PMID: 37667323 PMCID: PMC10478473 DOI: 10.1186/s13071-023-05918-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 08/06/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Pathogens face strong selection from host immune responses, yet many host populations support pervasive pathogen populations. We investigated this puzzle in a model system of Bartonella and rodents from Israel's northwestern Negev Desert. We chose to study this system because, in this region, 75-100% of rodents are infected with Bartonella at any given time, despite an efficient immunological response. In this region, Bartonella species circulate in three rodent species, and we tested the hypothesis that at least one of these hosts exhibits a waning immune response to Bartonella, which allows reinfections. METHODS We inoculated captive animals of all three rodent species with the same Bartonella strain, and we quantified the bacterial dynamics and Bartonella-specific immunoglobulin G antibody kinetics over a period of 139 days after the primary inoculation, and then for 60 days following reinoculation with the same strain. RESULTS Contrary to our hypothesis, we found a strong, long-lasting immunoglobulin G antibody response, with protective immunological memory in all three rodent species. That response prevented reinfection upon exposure of the rodents to the same Bartonella strain. CONCLUSIONS This study constitutes an initial step toward understanding how the interplay between traits of Bartonella and their hosts influences the epidemiological dynamics of these pathogens in nature.
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Affiliation(s)
- Ruth Rodríguez-Pastor
- Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
| | - Adam Z Hasik
- Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Nadav Knossow
- The Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 849900, Midreshet Ben-Gurion, Israel
| | - Enav Bar-Shira
- Section of Immunology, Department of Animal Sciences, Faculty of Agricultural, Nutritional and Environmental Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Naama Shahar
- The Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 849900, Midreshet Ben-Gurion, Israel
| | - Ricardo Gutiérrez
- National Reference Center for Bacteriology, Costa Rican Institute for Research and Teaching in Nutrition and Health (INCIENSA), Cartago, Costa Rica
| | - Luis Zaman
- Department of Ecology and Evolutionary Biology, Center for the Study of Complex Systems (CSCS), University of Michigan, Ann Arbor, MI, USA
| | - Shimon Harrus
- Koret School of Veterinary Medicine, Faculty of Agricultural, Nutritional and Environmental Sciences, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Richard E Lenski
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Hadas Hawlena
- The Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 849900, Midreshet Ben-Gurion, Israel.
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3
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Ahlawat N, Maggu K, Jigisha, Arun MG, Meena A, Agarwala A, Prasad NG. No major cost of evolved survivorship in Drosophila melanogaster populations coevolving with Pseudomonas entomophila. Proc Biol Sci 2022; 289:20220532. [PMID: 35506222 PMCID: PMC9065972 DOI: 10.1098/rspb.2022.0532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Rapid exaggeration of host and pathogen traits via arms race dynamics is one possible outcome of host-pathogen coevolution. However, the exaggerated traits are expected to incur costs in terms of resource investment in other life-history traits. The current study investigated the costs associated with evolved traits in a host-pathogen coevolution system. We used the Drosophila melanogaster (host)-Pseudomonas entomophila (pathogen) system to experimentally derive two selection regimes, one where the host and pathogen both coevolved, and the other, where only the host evolved against a non-evolving pathogen. After 17 generations of selection, we found that hosts from both selected populations had better post-infection survivorship than controls. Even though the coevolving populations tended to have better survivorship post-infection, we found no clear evidence that the two selection regimes were significantly different from each other. There was weak evidence for the coevolving pathogens being more virulent than the ancestral pathogen. We found no major cost of increased post-infection survivorship. The costs were not different between the coevolving hosts and the hosts evolving against a non-evolving pathogen. We found no evolved costs in the coevolving pathogens. Thus, our results suggest that increased host immunity and pathogen virulence may not be costly.
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Affiliation(s)
- Neetika Ahlawat
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India
| | - Komal Maggu
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Evolutionary and Environmental Studies, University of Zürich, Zürich 8057, Switzerland
| | - Jigisha
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Plant and Microbial Biology, University of Zürich, Zürich 8008, Switzerland
| | - Manas Geeta Arun
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India
| | - Abhishek Meena
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Evolutionary and Environmental Studies, University of Zürich, Zürich 8057, Switzerland
| | - Amisha Agarwala
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - Nagaraj Guru Prasad
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India
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Lewis JA, Penley MJ, Sylla H, Ahumada SD, Morran LT. Antagonistic Coevolution Limits the Range of Host Defense in C. elegans Populations. Front Cell Infect Microbiol 2022. [DOI: 10.3389/fcimb.2022.758745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Host populations often evolve defenses against parasites due to the significant fitness costs imposed by infection. However, adaptation to a specific parasite may alter the effectiveness of the host’s defenses in general. Consequently, the specificity of host defense may be influenced by a host population’s evolutionary history with parasites. Further, the degree of reciprocal change within an interaction may profoundly alter the range of host defense, given that antagonistic coevolutionary interactions are predicted to favor defense against specific parasite genotypes. Here, we examined the effect of host evolutionary history on host defense range by assessing the mortality rates of Caenorhabditis elegans host populations exposed to an array of Serratia marcescens bacterial parasite strains. Importantly, each of the host populations were derived from the same genetic background but have different experimental evolution histories with parasites. Each of these histories (exposure to either heat-killed, fixed genotype, or coevolving parasites) carries a different level of evolutionary reciprocity. Overall, we observed an effect of host evolutionary history in that previously coevolved host populations were generally the most susceptible to novel parasite strains. This data demonstrates that host evolutionary history can have a significant impact on host defense, and that host-parasite coevolution can increase host susceptibility to novel parasites.
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5
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Rovenolt FH, Tate AT. The Impact of Coinfection Dynamics on Host Competition and Coexistence. Am Nat 2022; 199:91-107. [DOI: 10.1086/717180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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6
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Papkou A, Schalkowski R, Barg MC, Koepper S, Schulenburg H. Population size impacts host-pathogen coevolution. Proc Biol Sci 2021; 288:20212269. [PMID: 34905713 PMCID: PMC8670963 DOI: 10.1098/rspb.2021.2269] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 11/18/2021] [Indexed: 11/25/2022] Open
Abstract
Ongoing host-pathogen interactions are characterized by rapid coevolutionary changes forcing species to continuously adapt to each other. The interacting species are often defined by finite population sizes. In theory, finite population size limits genetic diversity and compromises the efficiency of selection owing to genetic drift, in turn constraining any rapid coevolutionary responses. To date, however, experimental evidence for such constraints is scarce. The aim of our study was to assess to what extent population size influences the dynamics of host-pathogen coevolution. We used Caenorhabditus elegans and its pathogen Bacillus thuringiensis as a model for experimental coevolution in small and large host populations, as well as in host populations which were periodically forced through a bottleneck. By carefully controlling host population size for 23 host generations, we found that host adaptation was constrained in small populations and to a lesser extent in the bottlenecked populations. As a result, coevolution in large and small populations gave rise to different selection dynamics and produced different patterns of host-pathogen genotype-by-genotype interactions. Our results demonstrate a major influence of host population size on the ability of the antagonists to co-adapt to each other, thereby shaping the dynamics of antagonistic coevolution.
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Affiliation(s)
- Andrei Papkou
- Department of Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universitaet Kiel, 24098 Kiel, Germany
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Rebecca Schalkowski
- Department of Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universitaet Kiel, 24098 Kiel, Germany
| | - Mike-Christoph Barg
- Department of Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universitaet Kiel, 24098 Kiel, Germany
| | - Svenja Koepper
- Department of Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universitaet Kiel, 24098 Kiel, Germany
| | - Hinrich Schulenburg
- Department of Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universitaet Kiel, 24098 Kiel, Germany
- Max-Planck Institute for Evolutionary Biology, 24306 Plön, Germany
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7
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Raymond B, Erdos Z. Passage and the evolution of virulence in invertebrate pathogens: Fundamental and applied perspectives. J Invertebr Pathol 2021; 187:107692. [PMID: 34798134 DOI: 10.1016/j.jip.2021.107692] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 01/05/2023]
Abstract
Understanding the ecological and genetic factors that determine the evolution of virulence has broad value for invertebrate pathology. In addition to helping us understand the fundamental biology of our study organisms this body of theory has important applications in microbial biocontrol. Experimental tests of virulence theory are often carried out in invertebrate models and yet theory rarely informs applied passage experiments that aim to increase or maintain virulence. This review summarizes recent progress in this field with a focus on work most relevant to biological control: the virulence of invertebrate pathogens that are 'obligate killers' and which require cadavers for the production of infectious propagules. We discuss recent theory and fundamental and applied experimental evolution with bacteria, fungi, baculoviruses and nematodes. While passage experiments using baculoviruses have a long history of producing isolates with increased virulence, studies with other pathogens have not been so successful. Recent passage experiments that have applied evolution of virulence frameworks based on cooperation (kin selection) have produced novel methods and promising mutants with increased killing power. Evolution of virulence theory can provide plausible explanations for the varied results of passage experiments as well as a predictive framework for improving artificial selection.
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Affiliation(s)
- Ben Raymond
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, TR10 9FE, UK.
| | - Zoltan Erdos
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, TR10 9FE, UK
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8
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Ahlawat N, Geeta Arun M, Maggu K, Prasad NG. Enemies make you stronger: Coevolution between fruit fly host and bacterial pathogen increases postinfection survivorship in the host. Ecol Evol 2021; 11:9563-9574. [PMID: 34306643 PMCID: PMC8293768 DOI: 10.1002/ece3.7774] [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] [Received: 01/20/2021] [Revised: 05/01/2021] [Accepted: 05/11/2021] [Indexed: 11/16/2022] Open
Abstract
Multiple laboratory studies have evolved hosts against a nonevolving pathogen to address questions about evolution of immune responses. However, an ecologically more relevant scenario is one where hosts and pathogens can coevolve. Such coevolution between the antagonists, depending on the mutual selection pressure and additive variance in the respective populations, can potentially lead to a different pattern of evolution in the hosts compared to a situation where the host evolves against a nonevolving pathogen. In the present study, we used Drosophila melanogaster as the host and Pseudomonas entomophila as the pathogen. We let the host populations either evolve against a nonevolving pathogen or coevolve with the same pathogen. We found that the coevolving hosts on average evolved higher survivorship against the coevolving pathogen and ancestral (nonevolving) pathogen relative to the hosts evolving against a nonevolving pathogen. The coevolving pathogens evolved greater ability to induce host mortality even in nonlocal (novel) hosts compared to infection by an ancestral (nonevolving) pathogen. Thus, our results clearly show that the evolved traits in the host and the pathogen under coevolution can be different from one-sided adaptation. In addition, our results also show that the coevolving host-pathogen interactions can involve certain general mechanisms in the pathogen, leading to increased mortality induction in nonlocal or novel hosts.
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Affiliation(s)
- Neetika Ahlawat
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
| | - Manas Geeta Arun
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
| | - Komal Maggu
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
| | - Nagaraj Guru Prasad
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
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Turner WC, Kamath PL, van Heerden H, Huang YH, Barandongo ZR, Bruce SA, Kausrud K. The roles of environmental variation and parasite survival in virulence-transmission relationships. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210088. [PMID: 34109041 PMCID: PMC8170194 DOI: 10.1098/rsos.210088] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Disease outbreaks are a consequence of interactions among the three components of a host-parasite system: the infectious agent, the host and the environment. While virulence and transmission are widely investigated, most studies of parasite life-history trade-offs are conducted with theoretical models or tractable experimental systems where transmission is standardized and the environment controlled. Yet, biotic and abiotic environmental factors can strongly affect disease dynamics, and ultimately, host-parasite coevolution. Here, we review research on how environmental context alters virulence-transmission relationships, focusing on the off-host portion of the parasite life cycle, and how variation in parasite survival affects the evolution of virulence and transmission. We review three inter-related 'approaches' that have dominated the study of the evolution of virulence and transmission for different host-parasite systems: (i) evolutionary trade-off theory, (ii) parasite local adaptation and (iii) parasite phylodynamics. These approaches consider the role of the environment in virulence and transmission evolution from different angles, which entail different advantages and potential biases. We suggest improvements to how to investigate virulence-transmission relationships, through conceptual and methodological developments and taking environmental context into consideration. By combining developments in life-history evolution, phylogenetics, adaptive dynamics and comparative genomics, we can improve our understanding of virulence-transmission relationships across a diversity of host-parasite systems that have eluded experimental study of parasite life history.
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Affiliation(s)
- Wendy C. Turner
- US Geological Survey, Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Pauline L. Kamath
- School of Food and Agriculture, University of Maine, Orono, ME 04469, USA
| | - Henriette van Heerden
- Faculty of Veterinary Science, Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, South Africa
| | - Yen-Hua Huang
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Zoe R. Barandongo
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Spencer A. Bruce
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Kyrre Kausrud
- Section for Epidemiology, Norwegian Veterinary Institute, Ullevålsveien 68, 0454 Oslo, Norway
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Zhou Z, Jian X, Zhou B, Lu K, Wang Y. Changes in the immune function of rainbow trout (Oncorhynchus mykiss) provide insights into strategies against BDE-47 stress. JOURNAL OF HAZARDOUS MATERIALS 2020; 392:122212. [PMID: 32078968 DOI: 10.1016/j.jhazmat.2020.122212] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are ubiquitous in marine ecosystems and have been suggested to bioaccumulate in aquatic food webs, with potentially negative impacts on marine organism. In this study, a 21-day experiment was performed under controlled laboratory conditions, in which 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), the most biotoxic PBDE in the marine environment, was fed to rainbow trout (Oncorhynchus mykiss) at concentrations of 50 and 500 ng g-1 in the diet. BDE-47 significantly decreased the specific growth rate of O. mykiss and was highly concentrated in the liver and head kidney, as evidenced by increased bioaccumulation factor (BAF) values. Tissue observation revealed impairment of the microstructure of the head kidney. Important immune factors in the skin, blood and head kidney were significantly inhibited by BDE-47 treatment (p < 0.05), whereas the respiratory burst activity of macrophages was enhanced. Additionally, immune-related genes were strongly downregulated following BDE-47 exposure (p < 0.05). In a bacterial challenge, the treatment groups had much higher mortality than did the control group (p < 0.05). BDE-47 accumulated and impaired immune organs, and the hierarchy of immune responses was impaired, consequently reducing O. mykiss resistance to pathogen invasion.
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Affiliation(s)
- Zhongyuan Zhou
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China
| | - Xiaoyang Jian
- North China Sea Environmental Monitoring Centre, State Oceanic Administration, Fushun Road 22, Qingdao, 266003, China
| | - Bin Zhou
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
| | - Keyu Lu
- Department of Geography, University College London, London, WC1E 6BT, UK
| | - You Wang
- Department of Marine Ecology, College of Marine Life Science, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
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Tepolt CK, Darling JA, Blakeslee AMH, Fowler AE, Torchin ME, Miller AW, Ruiz GM. Recent introductions reveal differential susceptibility to parasitism across an evolutionary mosaic. Evol Appl 2020; 13:545-558. [PMID: 32431735 PMCID: PMC7045710 DOI: 10.1111/eva.12865] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 08/09/2019] [Accepted: 08/14/2019] [Indexed: 12/26/2022] Open
Abstract
Parasitism can represent a potent agent of selection, and introduced parasites have the potential to substantially alter their new hosts' ecology and evolution. While significant impacts have been reported for parasites that switch to new host species, the effects of macroparasite introduction into naïve populations of host species with which they have evolved remain poorly understood. Here, we investigate how the estuarine white-fingered mud crab (Rhithropanopeus harrisii) has adapted to parasitism by an introduced rhizocephalan parasite (Loxothylacus panopaei) that castrates its host. While the host crab is native to much of the East and Gulf Coasts of North America, its parasite is native only to the southern end of this range. Fifty years ago, the parasite invaded the mid-Atlantic, gradually expanding through previously naïve host populations. Thus, different populations of the same host species have experienced different degrees of historical interaction (and thus potential evolutionary response time) with the parasite: long term, short term, and naïve. In nine estuaries across this range, we examined whether and how parasite prevalence and host susceptibility to parasitism differs depending on the length of the host's history with the parasite. In field surveys, we found that the parasite was significantly more prevalent in its introduced range (i.e., short-term interaction) than in its native range (long-term interaction), a result that was also supported by a meta-analysis of prevalence data covering the 50 years since its introduction. In controlled laboratory experiments, host susceptibility to parasitism was significantly higher in naïve hosts than in hosts from the parasite's native range, suggesting that host resistance to parasitism is under selection. These results suggest that differences in host-parasite historical interaction can alter the consequences of parasite introductions in host populations. As anthropogenically driven range shifts continue, disruptions of host-parasite evolutionary relationships may become an increasingly important driver of ecological and evolutionary change.
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Affiliation(s)
- Carolyn K. Tepolt
- Department of BiologyWoods Hole Oceanographic InstitutionWoods HoleMAUSA
- Smithsonian Environmental Research CenterEdgewaterMDUSA
| | - John A. Darling
- National Exposure Research LaboratoryUS Environmental Protection AgencyResearch Triangle ParkNCUSA
| | | | - Amy E. Fowler
- Department of Environmental Science and PolicyGeorge Mason UniversityFairfaxVAUSA
| | - Mark E. Torchin
- Smithsonian Tropical Research InstituteBalboaAnconRepublic of Panama
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Orlansky S, Ben-Ami F. Genetic resistance and specificity in sister taxa of Daphnia: insights from the range of host susceptibilities. Parasit Vectors 2019; 12:545. [PMID: 31747976 PMCID: PMC6864995 DOI: 10.1186/s13071-019-3795-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 11/07/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Host genetic diversity can affect various aspects of host-parasite interactions, including individual-level effects on parasite infectivity, production of transmission stages and virulence, as well as population-level effects that reduce disease spread and prevalence, and buffer against widespread epidemics. However, a key aspect of this diversity, the genetic variation in host susceptibility, has often been neglected in interpreting empirical data and in theoretical studies. Daphnia similis naturally coexists with its competitor Daphnia magna and is more resistant to the endoparasitic microsporidium Hamiltosporidium tvaerminnensis, as suggested by a previous survey of waterbodies, which detected this parasite in D. magna, but not in D. similis. However, under laboratory conditions D. similis was sometimes found to be susceptible. We therefore asked if there is genetic variation for disease trait expression, and if the genetic variation in disease traits in D. similis is different from that of D. magna. METHODS We exposed ten clones of D. similis and ten clones of D. magna to three isolates of H. tvaerminnensis, and measured infection rates, parasite-induced host mortality and parasite spore production. RESULTS The two Daphnia species differ in the range and variation of their susceptibilities. The parasite produced on average two-fold more spores when growing in D. magna clones than in D. similis clones. CONCLUSIONS We confirm that D. similis is indeed much more resistant than D. magna and suggest that this could create a dilution effect in habitats where both species coexist.
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Affiliation(s)
- Sigal Orlansky
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
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13
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Koskella B. Resistance gained, resistance lost: An explanation for host-parasite coexistence. PLoS Biol 2018; 16:e3000013. [PMID: 30248103 PMCID: PMC6171958 DOI: 10.1371/journal.pbio.3000013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/04/2018] [Indexed: 01/21/2023] Open
Abstract
Host populations are under continual selection by parasites due to reduced fitness of infected individuals relative to uninfected individuals. This should select for host resistance against parasites, and ample evidence from the laboratory and natural populations demonstrates that hosts can respond rapidly to parasitism by evolving resistance. Why then do parasites still exist? In part, this is due to ongoing arms races as parasites evolve counteradaptations to overcome resistance and to the presence of spatial structure and refuges. However, host-parasite coexistence can also be explained through loss of resistance over time due either to selection against costly resistance mechanisms or constant loss of resistance via reversion mutations.
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Affiliation(s)
- Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, United States of America
- * E-mail:
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14
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Lopez-Ezquerra A, Mitschke A, Bornberg-Bauer E, Joop G. Tribolium castaneum gene expression changes after Paranosema whitei infection. J Invertebr Pathol 2018; 153:92-98. [DOI: 10.1016/j.jip.2018.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/10/2018] [Accepted: 02/12/2018] [Indexed: 12/24/2022]
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15
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Cross-Resistance: A Consequence of Bi-partite Host-Parasite Coevolution. INSECTS 2018; 9:insects9010028. [PMID: 29495405 PMCID: PMC5872293 DOI: 10.3390/insects9010028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/02/2018] [Accepted: 02/19/2018] [Indexed: 12/26/2022]
Abstract
Host-parasite coevolution can influence interactions of the host and parasite with the wider ecological community. One way that this may manifest is in cross-resistance towards other parasites, which has been observed to occur in some host-parasite evolution experiments. In this paper, we test for cross-resistance towards Bacillus thuringiensis and Pseudomonasentomophila in the red flour beetle Triboliumcastaneum, which was previously allowed to coevolve with the generalist entomopathogenic fungus Beauveriabassiana. We combine survival and gene expression assays upon infection to test for cross-resistance and underlying mechanisms. We show that larvae of T.castaneum that evolved with B.bassiana under coevolutionary conditions were positively cross-resistant to the bacterium B. thuringiensis, but not P.entomophila. Positive cross-resistance was mirrored at the gene expression level with markers that were representative of the oral route of infection being upregulated upon B.bassiana exposure. We find that positive cross-resistance towards B. thuringiensis evolved in T.castaneum as a consequence of its coevolutionary interactions with B.bassiana. This cross-resistance appears to be a consequence of resistance to oral toxicity. The fact that coevolution with B.bassiana results in resistance to B. thuringiensis, but not P.entomophila implies that B. thuringiensis and B.bassiana may share mechanisms of infection or toxicity not shared by P.entomophila. This supports previous suggestions that B.bassiana may possess Cry-like toxins, similar to those found in B. thuringiensis, which allow it to infect orally.
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16
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Rafaluk-Mohr C, Wagner S, Joop G. Cryptic changes in immune response and fitness in Tribolium castaneum as a consequence of coevolution with Beauveria bassiana. J Invertebr Pathol 2017; 152:1-7. [PMID: 29273219 DOI: 10.1016/j.jip.2017.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 11/15/2017] [Accepted: 12/15/2017] [Indexed: 10/18/2022]
Abstract
Immunity is a key trait in host defence against parasites and is thus likely to be under selection during host-parasite coevolution. Broadly, the immune system consists of several lines of defence including physiological innate immunity, physical barriers such as the cuticle, avoidance behaviours and in some cases antimicrobial secretions. The defence conferring the highest fitness benefit may be situation specific and depend on the taxon and infection route of the parasite. We carried out a host-parasite coevolution experiment between the red flour beetle T. castaneum, which possesses a comprehensive immune system including the ability to secrete antimicrobial compounds into its environment, and the generalist entomopathogenic fungus Beauveria bassiana. We measured levels of external immunity (benzoquinone secretion) and an internal immune trait, phenoloxidase (PO) activity throughout and in F2 to beetles at the end of the experiment. Survival (a proxy for resistance) of F2 coevolved and control beetles exposed to the fungus was also measured. No change in external immunity or survival was observed as a consequence of host-parasite coevolution, however, PO responses in evolved beetles showed increased flexibility dependent on the route of infection of the parasite. This more flexible PO response appeared to result in beetle populations being better able to cope with the parasite, buffering their fitness during the course of the coevolution experiment. This represents a subtle but significant adaptation to the presence of a parasite over evolutionary time.
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Affiliation(s)
- Charlotte Rafaluk-Mohr
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany; Institute for Insect Biotechnology, Justus Liebig University of Giessen, Heinrich-Buff-Ring 26-32, 25392 Giessen, Germany.
| | - Sophia Wagner
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Gerrit Joop
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany; Institute for Insect Biotechnology, Justus Liebig University of Giessen, Heinrich-Buff-Ring 26-32, 25392 Giessen, Germany.
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17
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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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18
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Rafaluk C, Yang W, Mitschke A, Rosenstiel P, Schulenburg H, Joop G. Highly potent host external immunity acts as a strong selective force enhancing rapid parasite virulence evolution. Environ Microbiol 2017; 19:2090-2100. [PMID: 28345225 DOI: 10.1111/1462-2920.13736] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/15/2022]
Abstract
Virulence is often under selection during host-parasite coevolution. In order to increase fitness, parasites are predicted to circumvent and overcome host immunity. A particular challenge for pathogens are external immune systems, chemical defence systems comprised of potent antimicrobial compounds released by prospective hosts into the environment. We carried out an evolution experiment, allowing for coevolution to occur, with the entomopathogenic fungus, Beauveria bassiana, and the red flour beetle, Tribolium castaneum, which has a well-documented external immune system with strong inhibitory effects against B. bassiana. After just seven transfers of experimental evolution we saw a significant increase in parasite induced host mortality, a proxy for virulence, in all B. bassiana lines. This apparent virulence increase was mainly the result of the B. bassiana lines evolving resistance to the beetles' external immune defences, not due to increased production of toxins or other harmful substances. Transcriptomic analyses of evolved B. bassiana implicated the up-regulation of oxidative stress resistance genes in the observed resistance to external immunity. It was concluded that external immunity acts as a powerful selective force for virulence evolution, with an increase in virulence being achieved apparently entirely by overcoming these defences, most likely due to elevated oxidative stress resistance.
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Affiliation(s)
- Charlotte Rafaluk
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel, 24118, Germany.,Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK.,Institute for Insect Biotechnology, University of Gießen, Heinrich-Buff-Ring 26-32, Gießen, D-35392, Germany
| | - Wentao Yang
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel, 24118, Germany
| | - Andreas Mitschke
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel, 24118, Germany.,Institute for Insect Biotechnology, University of Gießen, Heinrich-Buff-Ring 26-32, Gießen, D-35392, Germany
| | - Philip Rosenstiel
- Institute for Clinical Molecular Biology, Christian-Albrechts-Universität zu Kiel, Schittenhelmstrasse 12, Kiel, 24105, Germany
| | - Hinrich Schulenburg
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel, 24118, Germany
| | - Gerrit Joop
- Evolutionary Ecology and Genetics, Zoological Institute, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 1-9, Kiel, 24118, Germany.,Institute for Insect Biotechnology, University of Gießen, Heinrich-Buff-Ring 26-32, Gießen, D-35392, Germany
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19
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Kloesener MH, Bose J, Schulte RD. Experimental evolution with a multicellular host causes diversification within and between microbial parasite populations-Differences in emerging phenotypes of two different parasite strains. Evolution 2017; 71:2194-2205. [PMID: 28714591 DOI: 10.1111/evo.13306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 06/15/2017] [Accepted: 06/27/2017] [Indexed: 02/06/2023]
Abstract
Host-parasite coevolution is predicted to have complex evolutionary consequences, potentially leading to the emergence of genetic and phenotypic diversity for both antagonists. However, little is known about variation in phenotypic responses to coevolution between different parasite strains exposed to the same experimental conditions. We infected Caenorhabditis elegans with one of two strains of Bacillus thuringiensis and either allowed the host and the parasite to experimentally coevolve (coevolution treatment) or allowed only the parasite to adapt to the host (one-sided parasite adaptation). By isolating single parasite clones from evolved populations, we found phenotypic diversification of the ancestral strain into distinct clones, which varied in virulence toward ancestral hosts and competitive ability against other parasite genotypes. Parasite phenotypes differed remarkably not only between the two strains, but also between and within different replicate populations, indicating diversification of the clonal population caused by selection. This study highlights that the evolutionary selection pressure mediated by a multicellular host causes phenotypic diversification, but not necessarily with the same phenotypic outcome for different parasite strains.
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Affiliation(s)
- Michaela H Kloesener
- Department of Behavioural Biology, University of Osnabrueck, 49076, Osnabrueck, Germany
| | - Joy Bose
- Department of Behavioural Biology, University of Osnabrueck, 49076, Osnabrueck, Germany.,Evolutionary Biology Laboratory, Evolutionary and Integrative Biology Unit (EIBU), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P. O., Bangalore, 560064, India
| | - Rebecca D Schulte
- Department of Behavioural Biology, University of Osnabrueck, 49076, Osnabrueck, Germany
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20
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Kirschman LJ, Quade AH, Zera AJ, Warne RW. Immune function trade-offs in response to parasite threats. JOURNAL OF INSECT PHYSIOLOGY 2017; 98:199-204. [PMID: 28109904 DOI: 10.1016/j.jinsphys.2017.01.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 01/11/2017] [Accepted: 01/16/2017] [Indexed: 06/06/2023]
Abstract
Immune function is often involved in physiological trade-offs because of the energetic costs of maintaining constitutive immunity and mounting responses to infection. However, immune function is a collection of discrete immunity factors and animals should allocate towards factors that combat the parasite threat with the highest fitness cost. For example, animals on dispersal fronts of expanding population may be released from density-dependent diseases. The costs of immunity, however, and life history trade-offs in general, are often context dependent. Trade-offs are often most apparent under conditions of unusually limited resources or when animals are particularly stressed, because the stress response can shift priorities. In this study we tested how humoral and cellular immune factors vary between phenotypes of a wing dimorphic cricket and how physiological stress influences these immune factors. We measured constitutive lysozyme activity, a humoral immune factor, and encapsulation response, a cellular immune factor. We also stressed the crickets with a sham predator in a full factorial design. We found that immune strategy could be explained by the selective pressures encountered by each morph and that stress decreased encapsulation, but not lysozyme activity. These results suggest a possible trade-off between humoral and cellular immunity. Given limited resources and the expense of immune factors, parasite pressures could play a key factor in maintaining insect polyphenism via disruptive selection.
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Affiliation(s)
- Lucas J Kirschman
- Department of Zoology, Southern Illinois University, Carbondale, IL, USA.
| | - Adam H Quade
- Department of Zoology, Southern Illinois University, Carbondale, IL, USA
| | - Anthony J Zera
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Robin W Warne
- Department of Zoology, Southern Illinois University, Carbondale, IL, USA
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21
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Meaden S, Koskella B. Adaptation of the pathogen, Pseudomonas syringae, during experimental evolution on a native vs. alternative host plant. Mol Ecol 2017; 26:1790-1801. [PMID: 28207977 PMCID: PMC6849854 DOI: 10.1111/mec.14060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 12/19/2022]
Abstract
The specialization and distribution of pathogens among species has substantial impact on disease spread, especially when reservoir hosts can maintain high pathogen densities or select for increased pathogen virulence. Theory predicts that optimal within‐host growth rate will vary among host genotypes/species and therefore that pathogens infecting multiple hosts should experience different selection pressures depending on the host environment in which they are found. This should be true for pathogens with broad host ranges, but also those experiencing opportunistic infections on novel hosts or that spill over among host populations. There is very little empirical data, however, regarding how adaptation to one host might directly influence infectivity and growth on another. We took an experimental evolution approach to examine short‐term adaptation of the plant pathogen, Pseudomonas syringae pathovar tomato, to its native tomato host compared with an alternative host, Arabidopsis, in either the presence or absence of bacteriophages. After four serial passages (20 days of selection in planta), we measured bacterial growth of selected lines in leaves of either the focal or alternative host. We found that passage through Arabidopsis led to greater within‐host bacterial densities in both hosts than did passage through tomato. Whole genome resequencing of evolved isolates identified numerous single nucleotide polymorphisms based on our novel draft assembly for strain PT23. However, there was no clear pattern of clustering among plant selection lines at the genetic level despite the phenotypic differences observed. Together, the results emphasize that previous host associations can influence the within‐host growth rate of pathogens.
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Affiliation(s)
- Sean Meaden
- University of Exeter, Penryn Campus, Penryn, Cornwall, TR11 4EH, UK.,Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
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22
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Redman EM, Wilson K, Cory JS. Trade-offs and mixed infections in an obligate-killing insect pathogen. J Anim Ecol 2016; 85:1200-9. [PMID: 27155461 PMCID: PMC4988505 DOI: 10.1111/1365-2656.12547] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/24/2016] [Indexed: 02/01/2023]
Abstract
Natural populations of pathogens are frequently composed of numerous interacting strains. Understanding what maintains this diversity remains a key focus of research in disease ecology. In addition, within-host pathogen dynamics can have a strong impact on both infection outcome and the evolution of pathogen virulence, and thus, understanding the impact of pathogen diversity is important for disease management. We compared eight genetically distinguishable variants from Spodoptera exempta nucleopolyhedrovirus (SpexNPV) isolated from the African armyworm, Spodoptera exempta. NPVs are obligate killers, and the vast majority of transmission stages are not released until after the host has died. The NPV variants differed significantly in their virulence and could be clustered into two groups based on their dose-response curves. They also differed in their speed of kill and productivity (transmission potential) for S. exempta. The mixed-genotype wild-type (WT) SpexNPV, from which each variant was isolated, was significantly more virulent than any individual variant and its mean mortality rate was within the fastest group of individual variants. However, the WT virus produced fewer new infectious stages than any single variant, which might reflect competition among the variants. A survival analysis, combining the mortality and speed of kill data, confirmed the superiority of the genetically mixed WT virus over any single variant. Spodoptera exempta larvae infected with WT SpexNPV were predicted to die 2·7 and 1·9 times faster than insects infected with isolates from either of the two clusters of genotypes. Theory suggests that there are likely to be trade-offs between pathogen fitness traits. Across all larvae, there was a negative linear relationship between virus yield and speed of kill, such that more rapid host death carried the cost of producing fewer transmission stages. We also found a near-significant relationship for the same trend at the intervariant level. However, there was no evidence for a significant relationship between the induced level of mortality and transmission potential (virus yield) or speed of kill.
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Affiliation(s)
- Elizabeth M Redman
- Molecular Ecology and Biocontrol Group, NERC Centre for Ecology and Hydrology, Mansfield Road, Oxford, OX1 3SR, UK
| | - Kenneth Wilson
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Jenny S Cory
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, V5A 1S6, BC, Canada
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23
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Tate AT. The Interaction of Immune Priming with Different Modes of Disease Transmission. Front Microbiol 2016; 7:1102. [PMID: 27468283 PMCID: PMC4942476 DOI: 10.3389/fmicb.2016.01102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/01/2016] [Indexed: 12/25/2022] Open
Affiliation(s)
- Ann T Tate
- Department of Biology and Biochemistry, University of Houston Houston, TX, USA
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24
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Pieczynska MD, Wloch-Salamon D, Korona R, de Visser JAGM. Rapid multiple-level coevolution in experimental populations of yeast killer and nonkiller strains. Evolution 2016; 70:1342-53. [PMID: 27168531 DOI: 10.1111/evo.12945] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 04/26/2016] [Accepted: 04/28/2016] [Indexed: 01/09/2023]
Abstract
Coevolution between different biological entities is considered an important evolutionary mechanism at all levels of biological organization. Here, we provide evidence for coevolution of a yeast killer strain (K) carrying cytoplasmic dsRNA viruses coding for anti-competitor toxins and an isogenic toxin-sensitive strain (S) during 500 generations of laboratory propagation. Signatures of coevolution developed at two levels. One of them was coadaptation of K and S. Killing ability of K first increased quickly and was followed by the rapid invasion of toxin-resistant mutants derived from S, after which killing ability declined. High killing ability was shown to be advantageous when sensitive cells were present but costly when they were absent. Toxin resistance evolved via a two-step process, presumably involving the fitness-enhancing loss of one chromosome followed by selection of a recessive resistant mutation on the haploid chromosome. The other level of coevolution occurred between cell and killer virus. By swapping the killer viruses between ancestral and evolved strains, we could demonstrate that changes observed in both host and virus were beneficial only when combined, suggesting that they involved reciprocal changes. Together, our results show that the yeast killer system shows a remarkable potential for rapid multiple-level coevolution.
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Affiliation(s)
- Magdalena D Pieczynska
- Laboratory of Genetics, Wageningen University, 6708 PB Wageningen, The Netherlands.,Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow, Poland.,Current address: Kavli Institute of NanoScience, Delft University of Technology, 2600 GD Delft, The Netherlands
| | - Dominika Wloch-Salamon
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow, Poland
| | - Ryszard Korona
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, Krakow, Poland
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25
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Kalbe M, Eizaguirre C, Scharsack JP, Jakobsen PJ. Reciprocal cross infection of sticklebacks with the diphyllobothriidean cestode Schistocephalus solidus reveals consistent population differences in parasite growth and host resistance. Parasit Vectors 2016; 9:130. [PMID: 26951744 PMCID: PMC4782366 DOI: 10.1186/s13071-016-1419-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/02/2016] [Indexed: 11/19/2022] Open
Abstract
Background In host-parasite evolutionary arms races, parasites are generally expected to adapt more rapidly, due to their large population sizes and short generation times. There exist systems, though, where parasites cannot outpace their hosts because of similar generation times in both antagonists. In those cases concomitant adaptation is expected. Methods We tested this hypothesis in the three-spined stickleback-Schistocephalus solidus tapeworm system, where generation times are comparable in both organisms. We chose two populations of sticklebacks which differ prominently in the prevalence of S. solidus and consequently in its level of selective pressure. We performed a full factorial common garden experiment. Particularly, Norwegian (NO) and German (DE) sticklebacks, as well as hybrids between both stickleback populations and in both parental combinations, were exposed each to a single S. solidus originating from the same two host populations. Results We found the infection phenotype to depend on the host population, the parasite population, but not their interaction. NO-parasites showed higher infectivity than DE-parasites, with NO-sticklebacks also being more resistant to DE-parasites than to the sympatric NO-parasite. Reciprocally, DE-hosts were more susceptible to the allopatric NO-parasite while DE-parasites grew less than NO-parasites in all stickleback groups. Despite this asymmetry, the ratio of worm to host weight, an indicator of parasite virulence, was identical in both sympatric combinations, suggesting an optimal virulence as a common outcome of parallel coevolved systems. In hybrid sticklebacks, intermediate infection rates and growth of S. solidus from either origin suggests a simple genetic basis of resistance. However, comparison of infection phenotypes in NO-maternal and DE-maternal hybrid sticklebacks indicates local adaptation to the sympatric counterpart in both the host and the parasite. Conclusions Host-parasite systems with similar generation time show evidence for concomitant reciprocal adaptation resulting in parasite optimal virulence and host parasite specific resistance. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1419-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin Kalbe
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany.
| | - Christophe Eizaguirre
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany. .,School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Jörn P Scharsack
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany. .,Department of Animal Evolutionary Ecology, Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, 48149, Münster, Germany.
| | - Per J Jakobsen
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany. .,Institute for Biology, University of Bergen, Thor Møhlensgt. 55, 5020, Bergen, Norway.
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26
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Papkou A, Gokhale CS, Traulsen A, Schulenburg H. Host-parasite coevolution: why changing population size matters. ZOOLOGY 2016; 119:330-8. [PMID: 27161157 DOI: 10.1016/j.zool.2016.02.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/30/2016] [Accepted: 02/10/2016] [Indexed: 01/08/2023]
Abstract
Host-parasite coevolution is widely assumed to have a major influence on biological evolution, especially as these interactions impose high selective pressure on the reciprocally interacting antagonists. The exact nature of the underlying dynamics is yet under debate and may be determined by recurrent selective sweeps (i.e., arms race dynamics), negative frequency-dependent selection (i.e., Red Queen dynamics), or a combination thereof. These interactions are often associated with reciprocally induced changes in population size, which, in turn, should have a strong impact on co-adaptation processes, yet are neglected in most current work on the topic. Here, we discuss potential consequences of temporal variations in population size on host-parasite coevolution. The limited empirical data available and the current theoretical literature in this field highlight that the consideration of such interaction-dependent population size changes is likely key for the full understanding of the coevolutionary dynamics, and, thus, a more realistic view on the complex nature of species interactions.
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Affiliation(s)
- Andrei Papkou
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-University of Kiel, 24098, Kiel, Germany
| | - Chaitanya S Gokhale
- New Zealand Institute for Advanced Study, Massey University, Private Bag 102904, Auckland 0745, New Zealand
| | - Arne Traulsen
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, August-Thienemann-Straße 2, 24306 Plön, Germany
| | - Hinrich Schulenburg
- Department of Evolutionary Ecology and Genetics, Christian-Albrechts-University of Kiel, 24098, Kiel, Germany.
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27
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Rafaluk C, Jansen G, Schulenburg H, Joop G. When experimental selection for virulence leads to loss of virulence. Trends Parasitol 2015; 31:426-34. [DOI: 10.1016/j.pt.2015.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 06/01/2015] [Accepted: 06/15/2015] [Indexed: 11/30/2022]
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28
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Rapid evolution of virulence leading to host extinction under host-parasite coevolution. BMC Evol Biol 2015; 15:112. [PMID: 26070343 PMCID: PMC4464865 DOI: 10.1186/s12862-015-0407-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 06/02/2015] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Host-parasite coevolution is predicted to result in changes in the virulence of the parasite in order to maximise its reproductive success and transmission potential, either via direct host-to-host transfer or through the environment. The majority of coevolution experiments, however, do not allow for environmental transmission or persistence of long lived parasite stages, in spite of the fact that these may be critical for the evolutionary success of spore forming parasites under natural conditions. We carried out a coevolution experiment using the red flour beetle, Tribolium castaneum, and its natural microsporidian parasite, Paranosema whitei. Beetles and their environment, inclusive of spores released into it, were transferred from generation to generation. We additionally took a modelling approach to further assess the importance of transmissive parasite stages on virulence evolution. RESULTS In all parasite treatments of the experiment, coevolution resulted in extinction of the host population, with a pronounced increase in virulence being seen. Our modelling approach highlighted the presence of environmental transmissive parasite stages as being critical to the trajectory of virulence evolution in this system. CONCLUSIONS The extinction of host populations was unexpected, particularly as parasite virulence is often seen to decrease in host-parasite coevolution. This, in combination with the increase in virulence and results obtained from the model, suggest that the inclusion of transmissive parasite stages is important to improving our understanding of virulence evolution.
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Experimental removal of sexual selection leads to decreased investment in an immune component in female Tribolium castaneum. INFECTION GENETICS AND EVOLUTION 2015; 33:212-8. [PMID: 25958137 DOI: 10.1016/j.meegid.2015.05.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 04/29/2015] [Accepted: 05/05/2015] [Indexed: 11/22/2022]
Abstract
Because of divergent selection acting on males and females arising from different life-history strategies, polyandry can be expected to promote sexual dimorphism of investment into immune function. In previous work we have established the existence of such divergence within populations where males and females are exposed to varying degrees of polyandry. We here test whether the removal of sexual selection via enforced monogamy generates males and females that have similar levels of investment in immune function. To test this prediction experimentally, we measured differences between the sexes in a key immune measurement (phenoloxidase (PO) activity) and resistance to the microsporidian Paranosema whitei in Tribolium castaneum lines that evolved under monogamous (sexual selection absent) vs polyandrous (sexual selection present) mating systems. At generation 49, all selected lines were simultaneously assessed for PO activity and resistance to their natural parasite P. whitei after two generations of relaxed selection. We found that the polyandrous regime was associated with a clear dimorphism in immune function: females had significantly higher PO activities than males in these lines. In contrast, there was no such difference between the sexes in the lines evolving under the monogamous regime. Survival in the infection experiment did not differ between mating systems or sexes. Removing sexual selection via enforced monogamy thus seems to erase intersexual differences in immunity investment. We suggest that higher PO activities in females that have evolved under sexual selection might be driven by the increased risk of infections and/or injuries associated with exposure to multiple males.
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Goodacre SL, Fricke C, Martin OY. A screen for bacterial endosymbionts in the model organisms Tribolium castaneum, T. confusum, Callosobruchus maculatus, and related species. INSECT SCIENCE 2015; 22:165-177. [PMID: 24347564 DOI: 10.1111/1744-7917.12096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/03/2013] [Indexed: 06/03/2023]
Abstract
Reproductive parasites such as Wolbachia are extremely widespread amongst the arthropods and can have a large influence over the reproduction and fitness of their hosts. Undetected infections could thus confound the results of a wide range of studies that focus on aspects of host behavior, reproduction, fitness, and degrees of reproductive isolation. This potential problem has already been underlined by work investigating the incidence of Wolbachia infections in stocks of the model system Drosophila melanogaster. Here we survey a range of lab stocks of further commonly used model arthropods, focusing especially on the flour beetles Tribolium castaneum and Tribolium confusum, the cowpea weevil Callosobruchus maculatus and related species (Coleoptera: Tenebrionidae and Bruchidae). These species are widespread stored product pests so knowledge of infections with symbionts further has potential use in informing biocontrol measures. Beetles were assessed for infection with 3 known microbial reproductive parasites: Wolbachia, Rickettsia, Spiroplasma. Infections with some of these microbes were found in some of the lab stocks studied, although overall infections were relatively rare. The consequences of finding infections in these or other species and the type of previous studies likely to be affected most are discussed.
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Affiliation(s)
- Sara L Goodacre
- School of Biology, University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH, United Kingdom
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Kerstes NAG, Martin OY. Insect host-parasite coevolution in the light of experimental evolution. INSECT SCIENCE 2014; 21:401-414. [PMID: 24130157 DOI: 10.1111/1744-7917.12064] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/29/2013] [Indexed: 06/02/2023]
Abstract
The many ways parasites can impact their host species have been the focus of intense study using a range of approaches. A particularly promising but under-used method in this context is experimental evolution, because it allows targeted manipulation of known populations exposed to contrasting conditions. The strong potential of applying this method to the study of insect hosts and their associated parasites is demonstrated by the few available long-term experiments where insects have been exposed to parasites. In this review, we summarize these studies, which have delivered valuable insights into the evolution of resistance in response to parasite pressure, the underlying mechanisms, as well as correlated genetic responses. We further assess findings from relevant artificial selection studies in the interrelated contexts of immunity, life history, and reproduction. In addition, we discuss a number of well-studied Tribolium castaneum-Nosema whitei coevolution experiments in more detail and provide suggestions for research. Specifically, we suggest that future experiments should also be performed using nonmodel hosts and should incorporate contrasting experimental conditions, such as population sizes or environments. Finally, we expect that adding a third partner, for example, a second parasite or symbiont, to a host-parasite system could strongly impact (co)evolutionary dynamics.
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Affiliation(s)
- Niels A G Kerstes
- Experimental Ecology, Institute for Integrative Biology, D-USYS, ETH Zurich, Zurich, Switzerland
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Hangartner S, Sbilordo SH, Michalczyk Ł, Gage MJ, Martin OY. Are there genetic trade-offs between immune and reproductive investments in Tribolium castaneum? INFECTION GENETICS AND EVOLUTION 2013; 19:45-50. [DOI: 10.1016/j.meegid.2013.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 05/21/2013] [Accepted: 06/09/2013] [Indexed: 11/16/2022]
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Milutinović B, Stolpe C, Peuβ R, Armitage SAO, Kurtz J. The red flour beetle as a model for bacterial oral infections. PLoS One 2013; 8:e64638. [PMID: 23737991 PMCID: PMC3667772 DOI: 10.1371/journal.pone.0064638] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 04/17/2013] [Indexed: 01/03/2023] Open
Abstract
Experimental infection systems are important for studying antagonistic interactions and coevolution between hosts and their pathogens. The red flour beetle Tribolium castaneum and the spore-forming bacterial insect pathogen Bacillus thuringiensis (Bt) are widely used and tractable model organisms. However, they have not been employed yet as an efficient experimental system to study host-pathogen interactions. We used a high throughput oral infection protocol to infect T. castaneum insects with coleopteran specific B. thuringiensis bv. tenebrionis (Btt) bacteria. We found that larval mortality depends on the dietary spore concentration and on the duration of exposure to the spores. Furthermore, differential susceptibility of larvae from different T. castaneum populations indicates that the host genetic background influences infection success. The recovery of high numbers of infectious spores from the cadavers indicates successful replication of bacteria in the host and suggests that Btt could establish infectious cycles in T. castaneum in nature. We were able to transfer plasmids from Btt to a non-pathogenic but genetically well-characterised Bt strain, which was thereafter able to successfully infect T. castaneum, suggesting that factors residing on the plasmids are important for the virulence of Btt. The availability of a genetically accessible strain will provide an ideal model for more in-depth analyses of pathogenicity factors during oral infections. Combined with the availability of the full genome sequence of T. castaneum, this system will enable analyses of host responses during infection, as well as addressing basic questions concerning host-parasite coevolution.
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Affiliation(s)
- Barbara Milutinović
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Clemens Stolpe
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Robert Peuβ
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | | | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
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Kubinak JL, Potts WK. Host resistance influences patterns of experimental viral adaptation and virulence evolution. Virulence 2013; 4:410-8. [PMID: 23645287 DOI: 10.4161/viru.24724] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Infectious diseases are major threats to all living systems, so understanding the forces of selection that limit the evolution of more virulent pathogens is of fundamental importance; this includes the practical application of identifying possible mitigation strategies for at-risk host populations. The evolution of more virulent pathogens has been classically understood to be limited by the tradeoff between within-host growth rate and transmissibility. Importantly, heterogeneity among hosts can influence both of these factors. However, despite our substantial understanding of how the immune system operates to control pathogen replication during infection, we have only a limited appreciation of how variability in intrinsic (i.e., genetically determined) levels of host resistance influences patterns of pathogen adaptation and virulence evolution. Here, we describe results from experimental evolution studies using a model host-pathogen (virus-mammal) system; we demonstrate that variability in intrinsic levels of resistance among host genotypes can have significant effects on patterns of pathogen adaptation and virulence evolution during serial passage. Both the magnitude of adaptive response as well as the degree of pathogen specialization was positively correlated with host resistance, while mean overall virulence of post-passage virus was negatively correlated with host resistance. These results are consistent with a model whereby resistant host genotypes impose stronger selection on adapting pathogen populations, which in turn leads to the evolution of more specialized pathogen variants whose overall (i.e., mean) virulence across host genotypes is reduced.
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Affiliation(s)
- Jason L Kubinak
- Division of Microbiology and Immunology, Department of Pathology; School of Medicine, University of Utah; Salt Lake City, UT USA.
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35
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Brockhurst MA, Koskella B. Experimental coevolution of species interactions. Trends Ecol Evol 2013; 28:367-75. [PMID: 23523051 DOI: 10.1016/j.tree.2013.02.009] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 11/29/2022]
Abstract
Coevolution, the process of reciprocal adaptation and counter-adaptation between ecologically interacting species, affects most organisms and is considered a key force structuring biological diversity. Our understanding of the pattern and process of coevolution, particularly of antagonistic species interactions, has been hugely advanced in recent years by an upsurge in experimental studies that directly observe coevolution in the laboratory. These experiments pose new questions by revealing novel facets of the coevolutionary process not captured by current theory, while also providing the first empirical tests of longstanding coevolutionary ideas, including the influential Red Queen hypothesis. In this article, we highlight emerging directions for this field, including experimental coevolution of mutualistic interactions and understanding how pairwise coevolutionary processes scale up within species-rich communities.
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Kerstes NA, Bérénos C, Martin OY. Coevolving parasites and population size shape the evolution of mating behaviour. BMC Evol Biol 2013; 13:29. [PMID: 23379749 PMCID: PMC3570307 DOI: 10.1186/1471-2148-13-29] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 01/30/2013] [Indexed: 11/27/2022] Open
Abstract
Background Coevolution with parasites and population size are both expected to influence the evolution of mating rates. To gain insights into the interaction between these dual selective factors, we used populations from a coevolution experiment with the red flour beetle, Tribolium castaneum, and its microsporidian parasite, Nosema whitei. We maintained each experimental population at two different population sizes. We assayed the mating behaviour of both males and females from coevolved and paired non-coevolved control populations after 24 generations of coevolution with parasites. Results Males from large, coevolved populations (i.e. ancestors were exposed to parasites) showed a reduced eagerness to mate compared to males from large, non-coevolved populations. But in small populations, coevolution did not lead to decreased male mating rates. Coevolved females from both large and small populations appeared to be more willing to accept mating than non-coevolved females. Conclusions This study provides unique, experimental insights into the combined roles of coevolving parasites and population size on the evolution of mating rate. Furthermore, we find that males and females respond differently to the same environmental conditions. Our results show that parasites can be key determinants of the sexual behaviour of their hosts.
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Affiliation(s)
- Niels Ag Kerstes
- ETH Zürich, Institute of Integrative Biology, Experimental Ecology, Zürich, Switzerland.
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37
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Boughalmi M, Pagnier I, Aherfi S, Colson P, Raoult D, La Scola B. First Isolation of a Marseillevirus in the Diptera SyrphidaeEristalis tenax. Intervirology 2013; 56:386-94. [DOI: 10.1159/000354560] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Bérénos C, Schmid-Hempel P, Wegner KM. Antagonistic Coevolution Accelerates the Evolution of Reproductive Isolation in Tribolium castaneum. Am Nat 2012; 180:520-8. [DOI: 10.1086/667589] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Cory JS, Franklin MT. Evolution and the microbial control of insects. Evol Appl 2012; 5:455-69. [PMID: 22949921 PMCID: PMC3407864 DOI: 10.1111/j.1752-4571.2012.00269.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 04/24/2012] [Indexed: 11/26/2022] Open
Abstract
Insect pathogens can be utilized in a variety of pest management approaches, from inundative release to augmentation and classical biological control, and microevolution and the consideration of evolutionary principles can potentially influence the success of all these strategies. Considerable diversity exists in natural entomopathogen populations and this diversity can be either beneficial or detrimental for pest suppression, depending on the pathogen and its mode of competition, and this should be considered in the selection of isolates for biological control. Target hosts can exhibit considerable variation in their susceptibility to entomopathogens, and cases of field-evolved resistance have been documented for Bacillus thuringiensis and baculoviruses. Strong selection, limited pathogen diversity, reduced gene flow, and host plant chemistry are linked to cases of resistance and should be considered when developing resistance management strategies. Pre- and post-release monitoring of microbial control programs have received little attention; however, to date there have been no reports of host-range evolution or long-term negative effects on nontarget hosts. Comparative analyses of pathogen population structure, virulence, and host resistance over time are required to elucidate the evolutionary dynamics of microbial control systems.
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Affiliation(s)
- Jenny S Cory
- Department of Biological Sciences, Simon Fraser UniversityBurnaby, BC, Canada
- * Correspondence Jenny S. Cory, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. Tel.: 17787825714; fax: 17787823496; e-mail:
| | - Michelle T Franklin
- Department of Biological Sciences, Simon Fraser UniversityBurnaby, BC, Canada
- Department of Zoology, University of British ColumbiaVancouver, BC, Canada
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Chapuis E, Arnal A, Ferdy JB. Trade-offs shape the evolution of the vector-borne insect pathogen Xenorhabdus nematophila. Proc Biol Sci 2012; 279:2672-80. [PMID: 22398163 DOI: 10.1098/rspb.2012.0228] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Our current understanding on how pathogens evolve relies on the hypothesis that pathogens' transmission is traded off against host exploitation. In this study, we surveyed the possibility that trade-offs determine the evolution of the bacterial insect pathogen, Xenorhabdus nematophila. This bacterium rapidly kills the hosts it infects and is transmitted from host cadavers to new insects by a nematode vector, Steinernema carpocapsae. In order to detect trade-offs in this biological system, we produced 20 bacterial lineages using an experimental evolution protocol. These lineages differ, among other things, in their virulence towards the insect host. We found that nematode parasitic success increases with bacteria virulence, but their survival during dispersal decreases with the number of bacteria they carry. Other bacterial traits, such as production of the haemolytic protein XaxAB, have a strong impact on nematode reproduction. We then combined the result of our measurements with an estimate of bacteria fitness, which was divided into a parasitic component and a dispersal component. Contrary to what was expected in the trade-off hypothesis, we found no significant negative correlation between the two components of bacteria fitness. Still, we found that bacteria fitness is maximized when nematodes carry an intermediate number of cells. Our results therefore demonstrate the existence of a trade-off in X. nematophila, which is caused, in part, by the reduction in survival this bacterium causes to its nematode vectors.
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Affiliation(s)
- Elodie Chapuis
- Centre de Biologie pour la Gestion des Populations, UMR CBGP (INRA/IRD/Cirad/Montpellier SupAgro), Campus International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez, France
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Kerstes NAG, Bérénos C, Schmid-Hempel P, Wegner KM. Antagonistic experimental coevolution with a parasite increases host recombination frequency. BMC Evol Biol 2012; 12:18. [PMID: 22330615 PMCID: PMC3293731 DOI: 10.1186/1471-2148-12-18] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/13/2012] [Indexed: 11/10/2022] Open
Abstract
Background One of the big remaining challenges in evolutionary biology is to understand the evolution and maintenance of meiotic recombination. As recombination breaks down successful genotypes, it should be selected for only under very limited conditions. Yet, recombination is very common and phylogenetically widespread. The Red Queen Hypothesis is one of the most prominent hypotheses for the adaptive value of recombination and sexual reproduction. The Red Queen Hypothesis predicts an advantage of recombination for hosts that are coevolving with their parasites. We tested predictions of the hypothesis with experimental coevolution using the red flour beetle, Tribolium castaneum, and its microsporidian parasite, Nosema whitei. Results By measuring recombination directly in the individuals under selection, we found that recombination in the host population was increased after 11 generations of coevolution. Detailed insights into genotypic and phenotypic changes occurring during the coevolution experiment furthermore helped us to reconstruct the coevolutionary dynamics that were associated with this increase in recombination frequency. As coevolved lines maintained higher genetic diversity than control lines, and because there was no evidence for heterozygote advantage or for a plastic response of recombination to infection, the observed increase in recombination most likely represented an adaptive host response under Red Queen dynamics. Conclusions This study provides direct, experimental evidence for an increase in recombination frequency under host-parasite coevolution in an obligatory outcrossing species. Combined with earlier results, the Red Queen process is the most likely explanation for this observation.
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Affiliation(s)
- Niels A G Kerstes
- ETH Zürich, Institute of Integrative Biology, Experimental Ecology, CH-8092 Zürich, Switzerland.
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42
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Evison SEF, Roberts KE, Laurenson L, Pietravalle S, Hui J, Biesmeijer JC, Smith JE, Budge G, Hughes WOH. Pervasiveness of parasites in pollinators. PLoS One 2012; 7:e30641. [PMID: 22347356 PMCID: PMC3273957 DOI: 10.1371/journal.pone.0030641] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Accepted: 12/24/2011] [Indexed: 11/18/2022] Open
Abstract
Many pollinator populations are declining, with large economic and ecological implications. Parasites are known to be an important factor in the some of the population declines of honey bees and bumblebees, but little is known about the parasites afflicting most other pollinators, or the extent of interspecific transmission or vectoring of parasites. Here we carry out a preliminary screening of pollinators (honey bees, five species of bumblebee, three species of wasp, four species of hoverfly and three genera of other bees) in the UK for parasites. We used molecular methods to screen for six honey bee viruses, Ascosphaera fungi, Microsporidia, and Wolbachia intracellular bacteria. We aimed simply to detect the presence of the parasites, encompassing vectoring as well as actual infections. Many pollinators of all types were positive for Ascosphaera fungi, while Microsporidia were rarer, being most frequently found in bumblebees. We also detected that most pollinators were positive for Wolbachia, most probably indicating infection with this intracellular symbiont, and raising the possibility that it may be an important factor in influencing host sex ratios or fitness in a diversity of pollinators. Importantly, we found that about a third of bumblebees (Bombus pascuorum and Bombus terrestris) and a third of wasps (Vespula vulgaris), as well as all honey bees, were positive for deformed wing virus, but that this virus was not present in other pollinators. Deformed wing virus therefore does not appear to be a general parasite of pollinators, but does interact significantly with at least three species of bumblebee and wasp. Further work is needed to establish the identity of some of the parasites, their spatiotemporal variation, and whether they are infecting the various pollinator species or being vectored. However, these results provide a first insight into the diversity, and potential exchange, of parasites in pollinator communities.
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Affiliation(s)
- Sophie E. F. Evison
- Institute of Integrative and Comparative
Biology, University of Leeds, Leeds, United Kingdom
| | - Katherine E. Roberts
- Institute of Integrative and Comparative
Biology, University of Leeds, Leeds, United Kingdom
| | - Lynn Laurenson
- National Bee Unit, Food and Environment
Research Agency, York, United Kingdom
| | | | - Jeffrey Hui
- Center for Infection and Immunity, Columbia
University, New York, New York, United States of America
| | - Jacobus C. Biesmeijer
- Institute of Integrative and Comparative
Biology, University of Leeds, Leeds, United Kingdom
- Netherlands Centre for Biodiversity NCB
Naturalis, Leiden, The Netherlands
| | - Judith E. Smith
- School of Environment and Life Sciences,
University of Salford, Salford, United Kingdom
| | - Giles Budge
- National Bee Unit, Food and Environment
Research Agency, York, United Kingdom
| | - William O. H. Hughes
- Institute of Integrative and Comparative
Biology, University of Leeds, Leeds, United Kingdom
- * E-mail:
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Bérénos C, Schmid-Hempel P, Wegner KM. Complex adaptive responses during antagonistic coevolution between Tribolium castaneum and its natural parasite Nosema whitei revealed by multiple fitness components. BMC Evol Biol 2012; 12:11. [PMID: 22280468 PMCID: PMC3305629 DOI: 10.1186/1471-2148-12-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 01/26/2012] [Indexed: 11/15/2022] Open
Abstract
Background Host-parasite coevolution can lead to local adaptation of either parasite or host if there is specificity (GxG interactions) and asymmetric evolutionary potential between host and parasite. This has been demonstrated both experimentally and in field studies, but a substantial proportion of studies fail to detect such clear-cut patterns. One explanation for this is that adaptation can be masked by counter-adaptation by the antagonist. Additionally, genetic architecture underlying the interaction is often highly complex thus preventing specific adaptive responses. Here, we have employed a reciprocal cross-infection experiment to unravel the adaptive responses of two components of fitness affecting both parties with different complexities of the underlying genetic architecture (i.e. mortality and spore load). Furthermore, our experimental coevolution of hosts (Tribolium castaneum) and parasites (Nosema whitei) included paired replicates of naive hosts from identical genetic backgrounds to allow separation between host- and parasite-specific responses. Results In hosts, coevolution led to higher resistance and altered resistance profiles compared to paired control lines. Host genotype × parasite genotype interactions (GH × GP) were observed for spore load (the trait of lower genetic complexity), but not for mortality. Overall parasite performance correlated with resistance of its matching host coevolution background reflecting a directional and unspecific response to strength of selection during coevolution. Despite high selective pressures exerted by the obligatory killing parasite, and host- and parasite-specific mortality profiles, no general pattern of local adaptation was observed, but one case of parasite maladaptation was consistently observed on both coevolved and control host populations. In addition, the use of replicate control host populations in the assay revealed one case of host maladaptation and one case of parasite adaptation that was masked by host counter-adaptation, suggesting the presence of complex and probably dynamically changing fitness landscapes. Conclusions Our results demonstrate that the use of replicate naive populations can be a useful tool to differentiate between host and parasite adaptation in complex and dynamic fitness landscapes. The absence of clear local adaptation patterns during coevolution with a sexual host showing a complex genetic architecture for resistance suggests that directional selection for generality may be more important attributes of host-parasite coevolution than commonly assumed.
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Affiliation(s)
- Camillo Bérénos
- Institute of Integrative Biology, Experimental Ecology, ETH Zürich Universitätstrasse 16, CHN K 12,2, 8092 Zürich, Switzerland.
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Koskella B, Lin DM, Buckling A, Thompson JN. The costs of evolving resistance in heterogeneous parasite environments. Proc Biol Sci 2011; 279:1896-903. [PMID: 22171085 DOI: 10.1098/rspb.2011.2259] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolution of host resistance to parasites, shaped by associated fitness costs, is crucial for epidemiology and maintenance of genetic diversity. Selection imposed by multiple parasites could be a particularly strong constraint, as hosts either accumulate costs of multiple specific resistances or evolve a more costly general resistance mechanism. We used experimental evolution to test how parasite heterogeneity influences the evolution of host resistance. We show that bacterial host populations evolved specific resistance to local bacteriophage parasites, regardless of whether they were in single or multiple-phage environments, and that hosts evolving with multiple phages were no more resistant to novel phages than those evolving with single phages. However, hosts from multiple-phage environments paid a higher cost, in terms of population growth in the absence of phage, for their evolved specific resistances than those from single-phage environments. Given that in nature host populations face selection pressures from multiple parasite strains and species, our results suggest that costs may be even more critical in shaping the evolution of resistance than previously thought. Furthermore, our results highlight that a better understanding of resistance costs under combined control strategies could lead to a more 'evolution-resistant' treatment of disease.
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Affiliation(s)
- Britt Koskella
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA.
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45
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Comparative analysis of detection limits and specificity of molecular diagnostic markers for three pathogens (Microsporidia, Nosema spp.) in the key pollinators Apis mellifera and Bombus terrestris. Parasitol Res 2011; 110:1403-10. [PMID: 21927870 DOI: 10.1007/s00436-011-2640-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/02/2011] [Indexed: 10/17/2022]
Abstract
Global pollinator decline has recently been discussed in the context of honey and bumble bee infections from various pathogens including viruses, bacteria, microsporidia and mites. The microsporidian pathogens Nosema apis, Nosema ceranae and Nosema bombi may in fact be major candidates contributing to this decline. Different molecular and non-molecular detection methods have been developed; however, a comparison, especially of the highly sensitive PCR based methods, is currently lacking. Here, we present the first comparative quantitative real-time PCR study of nine Nosema spp. primers within the framework of primer specificity and sensitivity. With the help of dilution series of defined numbers of spores, we reveal six primer pairs amplifying N. apis, six for N. bombi and four for N. ceranae. All appropriate primer pairs detected an amount of at least 10(4) spores, the majority of which were even as sensitive to detect such low amounts as 10(3) to ten spores. Species specificity of primers was observed for N. apis and N. bombi, but not for N. ceranae. Additionally, we did not find any significant correlation for the amplified fragments with PCR efficiency or the limit of detection. We discuss our findings on the background of false positive and negative results using quantitative real-time PCR. On the basis of these results, future research might be based on appropriate primer selection depending on the experimental needs. Primers may be selected on the basis of specificity or sensitivity. Pathogen species and load may be determined with higher precision enhancing all kinds of diagnostic studies.
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BÉRÉNOS C, SCHMID-HEMPEL P, WEGNER KM. Experimental coevolution leads to a decrease in parasite-induced host mortality. J Evol Biol 2011; 24:1777-82. [DOI: 10.1111/j.1420-9101.2011.02306.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Affiliation(s)
- Raoul K. Boughton
- Avian Ecology, Archbold Biological Station, 123 Main Drive, Venus, Florida, USA
| | - Gerrit Joop
- Institute of Integrative Biology,
Experimental Ecology, ETH Zürich, CH‐8092 Zürich, Switzerland
| | - Sophie A.O. Armitage
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, D‐48149 Münster, Germany
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Bérénos C, Wegner KM, Schmid-Hempel P. Antagonistic coevolution with parasites maintains host genetic diversity: an experimental test. Proc Biol Sci 2010; 278:218-24. [PMID: 20685701 DOI: 10.1098/rspb.2010.1211] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Genetic variation in natural populations is a prime prerequisite allowing populations to respond to selection, but is under constant threat from forces that tend to reduce it, such as genetic drift and many types of selection. Haldane emphasized the potential importance of parasites as a driving force of genetic diversity. His theory has been taken for granted ever since, but despite numerous studies showing correlations between genetic diversity and parasitism, Haldane's hypothesis has rarely been tested experimentally for unambiguous support. We experimentally staged antagonistic coevolution between the host Tribolium castaneum and its natural microsporidian parasite, Nosema whitei, to test for the relative importance of two separate evolutionary forces (drift and parasite-induced selection) on the maintenance of genetic variation. Our results demonstrate that coevolution with parasites indeed counteracts drift as coevolving populations had significantly higher levels of heterozygosity and allelic diversity. Genetic drift remained a strong force, strongly reducing genetic variation and increasing genetic differentiation in small populations. To our surprise, differentiation between the evolving populations was smaller when they coevolved with parasites, suggesting parallel balancing selection. Hence, our results experimentally vindicate Haldane's original hypothesis 60 years after its conception.
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Affiliation(s)
- Camillo Bérénos
- Institute of Integrative Biology, Experimental Ecology, , ETH Zürich Universitätstrasse 16, CHN K 12.2, 8092 Zürich, Switzerland.
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Multiple reciprocal adaptations and rapid genetic change upon experimental coevolution of an animal host and its microbial parasite. Proc Natl Acad Sci U S A 2010; 107:7359-64. [PMID: 20368449 DOI: 10.1073/pnas.1003113107] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The coevolution between hosts and parasites is predicted to have complex evolutionary consequences for both antagonists, often within short time periods. To date, conclusive experimental support for the predictions is available mainly for microbial host systems, but for only a few multicellular host taxa. We here introduce a model system of experimental coevolution that consists of the multicellular nematode host Caenorhabditis elegans and the microbial parasite Bacillus thuringiensis. We demonstrate that 48 host generations of experimental coevolution under controlled laboratory conditions led to multiple changes in both parasite and host. These changes included increases in the traits of direct relevance to the interaction such as parasite virulence (i.e., host killing rate) and host resistance (i.e., the ability to survive pathogens). Importantly, our results provide evidence of reciprocal effects for several other central predictions of the coevolutionary dynamics, including (i) possible adaptation costs (i.e., reductions in traits related to the reproductive rate, measured in the absence of the antagonist), (ii) rapid genetic changes, and (iii) an overall increase in genetic diversity across time. Possible underlying mechanisms for the genetic effects were found to include increased rates of genetic exchange in the parasite and elevated mutation rates in the host. Taken together, our data provide comprehensive experimental evidence of the consequences of host-parasite coevolution, and thus emphasize the pace and complexity of reciprocal adaptations associated with these antagonistic interactions.
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Forsgren E, Fries I. Comparative virulence of Nosema ceranae and Nosema apis in individual European honey bees. Vet Parasitol 2010; 170:212-7. [PMID: 20299152 DOI: 10.1016/j.vetpar.2010.02.010] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 02/03/2010] [Accepted: 02/10/2010] [Indexed: 01/26/2023]
Abstract
Nosema apis and Nosema ceranae are intracellular microsporidian parasites infecting the midgut epithelial cells of adult honey bees. N. ceranae was considered to be restricted to the Asian honey bee, Apis cerana, but is nowadays a parasite found also in the European honey bee (Apis mellifera) across most of the world. Recent surveys and experimental work suggest that N. ceranae is a serious threat to the global beekeeping industry. It has been suggested that N. ceranae induces significantly higher mortality in honey bees than N. apis, but little is known about their comparative virulence. In this study, we used in vivo infection experiments to study the two parasites' different virulence (i.e. multiplication rate and infectivity). A qPCR was developed to elucidate within host competition between the two parasites using mixed infections. The outcome of the experiments indicates minor differences in infectious dose and multiplication rate between the two species. Moreover, the mortality caused by N. ceranae was not significantly higher than for N. apis and N. ceranae appeared to have no competitive advantage within host.
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Affiliation(s)
- Eva Forsgren
- Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, Ulls väg 16, SE-750 07 Uppsala, Sweden.
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