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Castiglioni VG, Olmo-Uceda MJ, Martín S, Félix MA, González R, Elena SF. Experimental evolution of an RNA virus in Caenorhabditis elegans. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 123:105623. [PMID: 38901623 DOI: 10.1016/j.meegid.2024.105623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 06/02/2024] [Accepted: 06/17/2024] [Indexed: 06/22/2024]
Abstract
The discovery of Orsay virus (OrV), the first virus infecting wild populations of Caenorhabditis elegans, has boosted studies of viral immunity pathways in this nematode. Considering the many advantages that C. elegans offers for fundamental research in host-pathogen interactions, this pathosystem has high potential to become a model system for experimental virus evolution studies. However, the evolutionary constraints - i.e, the balance between genetic variation, selection, drift and historical contingency- operating in this pathosystem have barely been explored. Here we describe for the first time an evolution experiment of two different OrV strains in C. elegans. Comparison of the two ancestral strains showed differences in infectivity and sequence, and highlighted the importance of consistently normalize viral inocula for meaningful comparisons among strains. After 10 serial passages of evolution, we report slight changes in infectivity and non-synonymous mutations fixed in the evolved viral populations. In addition, we observed numerous minor variants emerging in the viral population. These minor variants were not randomly distributed along the genome but concentrated in polymorphic genomic regions. Overall, our work established the grounds for future experimental virus evolution studies using Caenorhabditis nematodes.
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Affiliation(s)
- Victoria G Castiglioni
- Instituto de Biología Integrativa de Sistemas (CSIC-Universitat de València), Paterna, 46980 València, Spain
| | - María J Olmo-Uceda
- Instituto de Biología Integrativa de Sistemas (CSIC-Universitat de València), Paterna, 46980 València, Spain
| | - Susana Martín
- Instituto de Biología Integrativa de Sistemas (CSIC-Universitat de València), Paterna, 46980 València, Spain
| | - Marie-Anne Félix
- Institut de Biologie de l'École Normale Supérieure, CNRS, INSERM, 75005 Paris, France
| | - Rubén González
- Instituto de Biología Integrativa de Sistemas (CSIC-Universitat de València), Paterna, 46980 València, Spain; Institut de Biologie de l'École Normale Supérieure, CNRS, INSERM, 75005 Paris, France.
| | - Santiago F Elena
- Instituto de Biología Integrativa de Sistemas (CSIC-Universitat de València), Paterna, 46980 València, Spain; Santa Fe Institute, Sant Fe, NM 87501, USA.
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2
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Poulin R, Salloum PM, Bennett J. Evolution of parasites in the Anthropocene: new pressures, new adaptive directions. Biol Rev Camb Philos Soc 2024. [PMID: 38984760 DOI: 10.1111/brv.13118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 06/27/2024] [Accepted: 07/02/2024] [Indexed: 07/11/2024]
Abstract
The Anthropocene is seeing the human footprint rapidly spreading to all of Earth's ecosystems. The fast-changing biotic and abiotic conditions experienced by all organisms are exerting new and strong selective pressures, and there is a growing list of examples of human-induced evolution in response to anthropogenic impacts. No organism is exempt from these novel selective pressures. Here, we synthesise current knowledge on human-induced evolution in eukaryotic parasites of animals, and present a multidisciplinary framework for its study and monitoring. Parasites generally have short generation times and huge fecundity, features that predispose them for rapid evolution. We begin by reviewing evidence that parasites often have substantial standing genetic variation, and examples of their rapid evolution both under conditions of livestock production and in serial passage experiments. We then present a two-step conceptual overview of the causal chain linking anthropogenic impacts to parasite evolution. First, we review the major anthropogenic factors impacting parasites, and identify the selective pressures they exert on parasites through increased mortality of either infective stages or adult parasites, or through changes in host density, quality or immunity. Second, we discuss what new phenotypic traits are likely to be favoured by the new selective pressures resulting from altered parasite mortality or host changes; we focus mostly on parasite virulence and basic life-history traits, as these most directly influence the transmission success of parasites and the pathology they induce. To illustrate the kinds of evolutionary changes in parasites anticipated in the Anthropocene, we present a few scenarios, either already documented or hypothetical but plausible, involving parasite taxa in livestock, aquaculture and natural systems. Finally, we offer several approaches for investigations and real-time monitoring of rapid, human-induced evolution in parasites, ranging from controlled experiments to the use of state-of-the-art genomic tools. The implications of fast-evolving parasites in the Anthropocene for disease emergence and the dynamics of infections in domestic animals and wildlife are concerning. Broader recognition that it is not only the conditions for parasite transmission that are changing, but the parasites themselves, is needed to meet better the challenges ahead.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Priscila M Salloum
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Jerusha Bennett
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
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3
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Singh BB, Ward MP, Dhand NK. Host characteristics and their influence on zoonosis, disease emergence and multi-host pathogenicity. One Health 2023; 17:100596. [PMID: 37404948 PMCID: PMC10316652 DOI: 10.1016/j.onehlt.2023.100596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/27/2023] [Accepted: 06/27/2023] [Indexed: 07/06/2023] Open
Abstract
The interplay between agent-host-environment characteristics is responsible for the emergence and zoonotic potential of infectious disease pathogens. Many studies have investigated key agent characteristics and environmental factors responsible for these phenomena. However, little is known about the role played by host characteristics in zoonoses, disease emergence and the ability of pathogens to infect multiple hosts. We compiled a dataset of 8114 vertebrate host-agent interactions from published literature. Multiple host characteristics and the pathogen's zoonotic, emergence and multi-host potential were then linked to the dataset. The associations between zoonotic, emerging human pathogen and multi-host pathogenicity and several host characteristics were explored using logistic regression models. The numbers of publications and sequences from the agent-host combinations were used to control for the research effort. Hosts in the class Aves (odds ratio [OR] 20.87, 95% CI 2.66-163.97) and Mammalia (OR 26.09, 95% CI 3.34-203.87) were more likely to host a zoonotic pathogen compared to the class Amphibia. Similarly, hosts having Bursa fabricii (i.e., birds) (OR 1.8, 95% CI 1.4-2.3) were more likely to host an emerging human pathogen. The odds of being a zoonotic pathogen were highest when the host female required a greater number of days for maturity, and the pathogen was able to affect a greater number of host species. In contrast, the hosts from which a higher number of pathogens were reported were less likely (OR 0.39, 95% CI 0.31-0.49) to be associated with an emerging human pathogen. The odds of an emerging human pathogen were highest when the host had a higher adult body mass, and the specific pathogen could affect more host species. The odds of a pathogen infecting multiple hosts were highest when a host had shorter female maturity days (>670-2830 days) and lower birth/hatching weight (>42.2-995 g) compared to longer female maturity days (>2830-6940 days) and greater birth/hatching weight (>3.31-1160 kg). We conclude that several host characteristics - such as mass, maturity, immune system and pathogen permissiveness- are linked with zoonoses, disease emergence or multi-host pathogenicity. These findings can contribute to preparedness for emerging infections and zoonotic diseases.
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Affiliation(s)
- Balbir B. Singh
- Sydney School of Veterinary Science, The University of Sydney, 425 Werombi Road, Camden, 2570, NSW, Australia
- Centre for One Health, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab 141004, India
| | - Michael P. Ward
- Sydney School of Veterinary Science, The University of Sydney, 425 Werombi Road, Camden, 2570, NSW, Australia
| | - Navneet K. Dhand
- Sydney School of Veterinary Science, The University of Sydney, 425 Werombi Road, Camden, 2570, NSW, Australia
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Taube K, Noreikiene K, Kahar S, Gross R, Ozerov M, Vasemägi A. Subtle transcriptomic response of Eurasian perch ( Perca fluviatilis) associated with Triaenophorus nodulosus plerocercoid infection. Int J Parasitol Parasites Wildl 2023; 22:146-154. [PMID: 37869060 PMCID: PMC10585624 DOI: 10.1016/j.ijppaw.2023.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 10/24/2023]
Abstract
Determining the physiological effects of parasites and characterizing genes involved in host responses to infections are essential to improving our understanding of host-parasite interactions and their ecological and evolutionary consequences. This task, however, is complicated by high diversity and complex life histories of many parasite species. The use of transcriptomics in the context of wild-caught specimens can help ameliorate this by providing both qualitative and quantitative information on gene expression patterns in response to parasites in specific host organs and tissues. Here, we evaluated the physiological impact of the widespread parasite, the pike tapeworm (Triaenophorus nodulosus), on its second intermediate host, the Eurasian perch (Perca fluviatilis). We used an RNAseq approach to analyse gene expression in the liver, the target organ of T. nodulosus plerocercoids, and spleen which is one of the main immune organs in teleost fishes. We compared perch collected from multiple lakes consisting of individuals with (n = 8) and without (n = 6) T. nodulosus plerocercoids in the liver. Results revealed a small number of differentially expressed genes (DEGs, adjusted p-value ≤0.05) in both spleen (n = 22) and liver (n = 10). DEGs in spleen consisted of mostly upregulated immune related genes (e.g., JUN, SIK1, THSB1), while those in the liver were often linked to metabolic functions (e.g., FABP1, CADM4, CDAB). However, Gene Ontology (GO) analysis showed lack of functional enrichment among DEGs. This study demonstrates that Eurasian perch displays a subtle response at a gene expression level to T. nodulosus plerocercoid infection. Given that plerocercoids are low-metabolic activity transmission stages, our results suggest that moderate T. nodulosus plerocercoid infection most likely does not provoke an extensive host immune response and have relatively low physiological costs for the host. Our findings illustrate that not all conspicuous infections have severe effects on host gene regulation.
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Affiliation(s)
- Konrad Taube
- Chair of Aquaculture, Estonian University of Life Sciences, Kreutzwaldi 46a, 51014 Tartu, Estonia
| | - Kristina Noreikiene
- Chair of Aquaculture, Estonian University of Life Sciences, Kreutzwaldi 46a, 51014 Tartu, Estonia
- Institute of Biosciences, Life Sciences Center, Vilnius University Vilnius, Lithuania
| | - Siim Kahar
- Chair of Aquaculture, Estonian University of Life Sciences, Kreutzwaldi 46a, 51014 Tartu, Estonia
| | - Riho Gross
- Chair of Aquaculture, Estonian University of Life Sciences, Kreutzwaldi 46a, 51014 Tartu, Estonia
| | - Mikhail Ozerov
- Biodiversity Unit, University of Turku, Vesilinnantie 5, 20500 Turku, Finland
| | - Anti Vasemägi
- Chair of Aquaculture, Estonian University of Life Sciences, Kreutzwaldi 46a, 51014 Tartu, Estonia
- Swedish University of Agricultural Sciences, Sötvattenslaboratoriet, Stångholmsvägen 2, 17893 Drottningholm, Sweden
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5
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Poulin R. Model worms: knowledge gains and risks associated with the use of model species in parasitological research. Parasitology 2023; 150:967-978. [PMID: 37853764 PMCID: PMC10941210 DOI: 10.1017/s0031182023000963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/05/2023] [Accepted: 10/07/2023] [Indexed: 10/20/2023]
Abstract
Model parasite species, whose entire life cycle can be completed in the laboratory and maintained for multiple generations, have played a fundamental role in our understanding of host–parasite interactions. Yet, keeping parasites in laboratory conditions may expose them to unnatural evolutionary pressures, and using laboratory cultures for research is therefore not without limitations. Using 2 widely-used model helminth species, the cestode Hymenolepis diminuta and the nematode Heligmosomoides polygyrus, I illustrate the caution needed when interpreting experimental results on model species. I first review more than 1200 experimental studies published on these species in the past 4 decades, to determine which research areas they have contributed to. This is followed by an examination of the institutional laboratory cultures that have provided the parasites used in these studies. Some of these have persisted for decades and accounted for a substantial proportion of published studies, whereas others have been short-lived. Using information provided by the curators of active cultures, I summarize data on their origins and maintenance conditions. Finally, I discuss how laboratory cultures may have been subject to the influence of evolutionary genetic processes, such as founder effects, genetic drift and inbreeding. I also address the possibility that serial passage through laboratory hosts across multiple generations has exerted artificial selection on several parasite traits, resulting in genetic and phenotypic divergence among laboratory cultures, and between these cultures and natural parasite populations. I conclude with recommendations for the continued usage of laboratory helminth cultures aimed at maximizing their important contribution to parasitological research.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
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6
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Han S, Lee P, Choi HJ. Non-Invasive Vaccines: Challenges in Formulation and Vaccine Adjuvants. Pharmaceutics 2023; 15:2114. [PMID: 37631328 PMCID: PMC10458847 DOI: 10.3390/pharmaceutics15082114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/07/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Given the limitations of conventional invasive vaccines, such as the requirement for a cold chain system and trained personnel, needle-based injuries, and limited immunogenicity, non-invasive vaccines have gained significant attention. Although numerous approaches for formulating and administrating non-invasive vaccines have emerged, each of them faces its own challenges associated with vaccine bioavailability, toxicity, and other issues. To overcome such limitations, researchers have created novel supplementary materials and delivery systems. The goal of this review article is to provide vaccine formulation researchers with the most up-to-date information on vaccine formulation and the immunological mechanisms available, to identify the technical challenges associated with the commercialization of non-invasive vaccines, and to guide future research and development efforts.
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Affiliation(s)
| | | | - Hyo-Jick Choi
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada; (S.H.); (P.L.)
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7
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Wu F. Updated analysis to reject the laboratory-engineering hypothesis of SARS-CoV-2. ENVIRONMENTAL RESEARCH 2023; 224:115481. [PMID: 36804316 PMCID: PMC9937728 DOI: 10.1016/j.envres.2023.115481] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
A clear understanding of the origin of SARS-CoV-2 is important for future pandemic preparedness. Here, I provided an updated analysis of the type IIS endonuclease maps in genomes of alphacoronavirus, betacoronavirus, and SARS-CoV-2. Scenarios to engineer SARS-CoV-2 in the laboratory and the associated workload was also discussed. The analysis clearly shows that the endonuclease fingerprint does not indicate a synthetic origin of SARS-CoV-2 and engineering a SARS-CoV-2 virus in the laboratory is extremely challenging both scientifically and financially. On the contrary, current scientific evidence does support the animal origin of SARS-CoV-2.
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Affiliation(s)
- Fuqing Wu
- Epidemiology, Human Genetics and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Texas, USA; Texas Epidemic Public Health Institute, TX, USA.
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8
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Kennedy DA. Death is overrated: the potential role of detection in driving virulence evolution. Proc Biol Sci 2023; 290:20230117. [PMID: 36987649 PMCID: PMC10050922 DOI: 10.1098/rspb.2023.0117] [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: 01/17/2023] [Accepted: 03/03/2023] [Indexed: 03/30/2023] Open
Abstract
A common assumption in the evolution of virulence theory literature is that pathogens transmit better when they exploit their host more heavily, but by doing so, they impose a greater risk of killing their host, thus truncating infectious periods and reducing their own opportunities for transmission. Here, I derive an equation for the magnitude of this cost in terms of the infection fatality rate, and in doing so, I show that there are many cases where mortality costs are too small to plausibly constrain increases in host exploitation by pathogens. I propose that pathogen evolution may often be constrained by detection costs, whereby hosts alter their behaviour when infection is detectable, and thus reduce pathogen opportunities for onward transmission. I then derive an inequality to illustrate when mortality costs or detection costs impose stronger constraints on pathogen evolution, and I use empirical data from the literature to demonstrate that detection costs are frequently large in both human and animal populations. Finally, I give examples of how evolutionary predictions can change depending on whether costs of host exploitation are borne out through mortality or detection.
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Affiliation(s)
- David A. Kennedy
- Department of Biology, Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
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9
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Kong P, Daughtrey ML, Hong C. Differential Adaptation Has Resulted in Aggressiveness Variation of Calonectria pseudonaviculata on Hosts Buxus, Pachysandra, and Sarcococca. J Fungi (Basel) 2023; 9:jof9020181. [PMID: 36836296 PMCID: PMC9966688 DOI: 10.3390/jof9020181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/23/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Calonectria pseudonaviculata (Cps) infects Buxus (boxwood), Pachysandra (pachysandra), and Sarcococca spp. (sweet box); yet, how it adapts to its hosts has been unclear. Here, we performed serial passage experiments with the three hosts and measured Cps changes in three aggressiveness components: infectibility, lesion size, and conidial production. The detached leaves of individual hosts were inoculated with isolates (P0) from the originating host, followed by nine serial inoculations of new leaves of the same host with conidia from the infected leaves of the previous inoculation. All boxwood isolates maintained their capability of infection and lesion expansion through the 10 passages, whereas most non-boxwood isolates lost these abilities during the passages. Isolates from plants of origin (*-P0) and their descendants isolated from passages 5 (*-P5) and 10 (*-P10) were used to evaluate aggressiveness changes on all three hosts with cross-inoculation. While post-passage boxwood isolates gave enlarged lesions on pachysandra, sweet box P5 and pachysandra P10 isolates showed reduced aggressiveness on all hosts. Cps appears to be most adapted to boxwood and less adapted to sweet box and pachysandra. These results suggest speciation of Cps, with its coevolutionary pace with the hosts the fastest with boxwood, intermediate with sweet box, and the slowest with pachysandra.
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Affiliation(s)
- Ping Kong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA 23455, USA
- Correspondence:
| | - Margery L. Daughtrey
- Long Island Horticultural Research and Extension Center, Cornell University, Riverhead, NY 11901, USA
| | - Chuanxue Hong
- Hampton Roads Agricultural Research and Extension Center, Virginia Tech, Virginia Beach, VA 23455, USA
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Dimitriu T, Souissi W, Morwool P, Darby A, Crickmore N, Raymond B. Selecting for infectivity across metapopulations can increase virulence in the social microbe
Bacillus thuringiensis. Evol Appl 2023; 16:705-720. [PMID: 36969139 PMCID: PMC10033855 DOI: 10.1111/eva.13529] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 12/27/2022] [Indexed: 01/18/2023] Open
Abstract
Passage experiments that sequentially infect hosts with parasites have long been used to manipulate virulence. However, for many invertebrate pathogens, passage has been applied naively without a full theoretical understanding of how best to select for increased virulence and this has led to very mixed results. Understanding the evolution of virulence is complex because selection on parasites occurs across multiple spatial scales with potentially different conflicts operating on parasites with different life histories. For example, in social microbes, strong selection on replication rate within hosts can lead to cheating and loss of virulence, because investment in public goods virulence reduces replication rate. In this study, we tested how varying mutation supply and selection for infectivity or pathogen yield (population size in hosts) affected the evolution of virulence against resistant hosts in the specialist insect pathogen Bacillus thuringiensis, aiming to optimize methods for strain improvement against a difficult to kill insect target. We show that selection for infectivity using competition between subpopulations in a metapopulation prevents social cheating, acts to retain key virulence plasmids, and facilitates increased virulence. Increased virulence was associated with reduced efficiency of sporulation, and possible loss of function in putative regulatory genes but not with altered expression of the primary virulence factors. Selection in a metapopulation provides a broadly applicable tool for improving the efficacy of biocontrol agents. Moreover, a structured host population can facilitate artificial selection on infectivity, while selection on life-history traits such as faster replication or larger population sizes can reduce virulence in social microbes.
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Affiliation(s)
- Tatiana Dimitriu
- Centre for Ecology and Conservation University of Exeter Penryn UK
| | - Wided Souissi
- School of Life Sciences University of Sussex Brighton UK
| | - Peter Morwool
- Centre for Ecology and Conservation University of Exeter Penryn UK
| | - Alistair Darby
- Centre for Genomic Research, Institute of Integrative Biology University of Liverpool Liverpool UK
| | - Neil Crickmore
- School of Life Sciences University of Sussex Brighton UK
| | - Ben Raymond
- Centre for Ecology and Conservation University of Exeter Penryn UK
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11
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Conselheiro JA, Barone GT, Miyagi SAT, de Souza Silva SO, Agostinho WC, Aguiar J, Brandão PE. Evolution of Rabies Virus Isolates: Virulence Signatures and Effects of Modulation by Neutralizing Antibodies. Pathogens 2022; 11:pathogens11121556. [PMID: 36558890 PMCID: PMC9782306 DOI: 10.3390/pathogens11121556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/05/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Lyssavirus rabies (RABV) is an RNA virus and, therefore, is subject to mutations due to low RNA polymerase replication fidelity, forming a population structure known as a viral quasispecies, which is the core of RNA viruses' adaptive strategy. Under new microenvironmental conditions, the fittest populations are selected, and the study of this process on the molecular level can help determine molecular signatures related to virulence. Our aim was to survey gene signatures on nucleoprotein and glycoprotein genes that might be involved in virulence modulation during the in vitro evolution of RABV lineages after serial passages in a neuronal cell system with or without the presence of neutralizing antibodies based on replicative fitness, in vivo neurotropism and protein structure and dynamics. The experiments revealed that amino acids at positions 186 and 188 of the glycoprotein are virulence factors of Lyssavirus rabies, and site 186 specifically might allow the attachment to heparan as a secondary cell receptor, while polymorphism at position 333 might allow the selection of escape mutants under suboptimal neutralizing antibodies titers.
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Affiliation(s)
- Juliana Amorim Conselheiro
- Laboratory of Diagnostics of Zoonosis and Vector-borne Diseases (LabZoo), Zoonosis Surveillance Division, Health Surveillance Coordination, Municipal Health Department, São Paulo 02031-020, SP, Brazil
- Correspondence:
| | - Gisely Toledo Barone
- Laboratory of Diagnostics of Zoonosis and Vector-borne Diseases (LabZoo), Zoonosis Surveillance Division, Health Surveillance Coordination, Municipal Health Department, São Paulo 02031-020, SP, Brazil
| | - Sueli Akemi Taniwaki Miyagi
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, SP, Brazil
| | - Sheila Oliveira de Souza Silva
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, SP, Brazil
| | - Washington Carlos Agostinho
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, SP, Brazil
| | - Joana Aguiar
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, SP, Brazil
| | - Paulo Eduardo Brandão
- Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of São Paulo, São Paulo 05508-270, SP, Brazil
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12
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Ameline C, Voegtli F, Andras J, Dexter E, Engelstädter J, Ebert D. Genetic slippage after sex maintains diversity for parasite resistance in a natural host population. SCIENCE ADVANCES 2022; 8:eabn0051. [PMID: 36399570 PMCID: PMC9674289 DOI: 10.1126/sciadv.abn0051] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Although parasite-mediated selection is a major driver of host evolution, its influence on genetic variation for parasite resistance is not yet well understood. We monitored resistance in a large population of the planktonic crustacean Daphnia magna over 8 years, as it underwent yearly epidemics of the bacterial pathogen Pasteuria ramosa. We observed cyclic dynamics of resistance: Resistance increased throughout the epidemics, but susceptibility was restored each spring when hosts hatched from sexual resting stages. Host resting stages collected across the year showed that largely resistant host populations can produce susceptible sexual offspring. A genetic model of resistance developed for this host-parasite system, based on multiple loci and strong epistasis, is in partial agreement with our findings. Our results reveal that, despite strong selection for resistance in a natural host population, genetic slippage after sexual reproduction can be a strong factor for the maintenance of genetic diversity of host resistance.
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Affiliation(s)
- Camille Ameline
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Felix Voegtli
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Jason Andras
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Eric Dexter
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
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13
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Rodríguez‐Pastor R, Shafran Y, Knossow N, Gutiérrez R, Harrus S, Zaman L, Lenski RE, Barrick JE, Hawlena H. A road map for in vivo evolution experiments with blood-borne parasitic microbes. Mol Ecol Resour 2022; 22:2843-2859. [PMID: 35599628 PMCID: PMC9796859 DOI: 10.1111/1755-0998.13649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 03/14/2022] [Accepted: 05/13/2022] [Indexed: 01/07/2023]
Abstract
Laboratory experiments in which blood-borne parasitic microbes evolve in their animal hosts offer an opportunity to study parasite evolution and adaptation in real time and under natural settings. The main challenge of these experiments is to establish a protocol that is both practical over multiple passages and accurately reflects natural transmission scenarios and mechanisms. We provide a guide to the steps that should be considered when designing such a protocol, and we demonstrate its use via a case study. We highlight the importance of choosing suitable ancestral genotypes, treatments, number of replicates per treatment, types of negative controls, dependent variables, covariates, and the timing of checkpoints for the experimental design. We also recommend specific preliminary experiments to determine effective methods for parasite quantification, transmission, and preservation. Although these methodological considerations are technical, they also often have conceptual implications. To this end, we encourage other researchers to design and conduct in vivo evolution experiments with blood-borne parasitic microbes, despite the challenges that the work entails.
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Affiliation(s)
- Ruth Rodríguez‐Pastor
- Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
| | - Yarden Shafran
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
| | - Nadav Knossow
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
| | - Ricardo Gutiérrez
- Koret School of Veterinary Medicine, Faculty of Agricultural, Nutritional and Environmental SciencesThe Hebrew University of JerusalemRehovotIsrael
| | - Shimon Harrus
- Koret School of Veterinary Medicine, Faculty of Agricultural, Nutritional and Environmental SciencesThe Hebrew University of JerusalemRehovotIsrael
| | - Luis Zaman
- Department of Ecology and Evolutionary Biology, The Center for the Study of Complex Systems (CSCS)University of MichiganAnn ArborMichiganUSA
| | - Richard E. Lenski
- Department of Microbiology and Molecular GeneticsMichigan State UniversityEast LansingMichiganUSA
| | - Jeffrey E. Barrick
- Department of Molecular BiosciencesThe University of Texas AustinAustinTexasUSA
| | - Hadas Hawlena
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, The Jacob Blaustein Institutes for Desert ResearchBen‐Gurion University of the NegevMidreshet Ben‐GurionIsrael
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14
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Stavtseva NA, Fielden LJ, Khokhlova IS, Krasnov BR. Fitness consequences of host colonization in two generalist fleas: Context-dependency and the effect of spatial co-occurrence. MEDICAL AND VETERINARY ENTOMOLOGY 2022; 36:347-355. [PMID: 35324014 DOI: 10.1111/mve.12570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/08/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
We studied the fitness consequences of colonizing a novel host by experimental lines of fleas (Synosternus cleopatrae and Xenopsylla ramesis) maintained for 18-22 generations on the principal or novel (sympatric or allopatric) hosts via number, developmental success and size of the offspring of the fleas exploiting these hosts. We asked whether (a) fitness on non-principal hosts increases after prolonged maintenance; (b) the colonization success depends on the spatial co-occurrence of a flea and a host and (c) colonization of a novel host is accompanied by a decreased ability to exploit an original host. The ability of fleas to colonize novel hosts differed between species, with S. cleopatrae, but not X. ramesis, increasing its offspring production on novel hosts. Spatial co-occurrence did not affect colonization success. Maintenance on an alternative host was not accompanied by decreased adaptation to the original host. When fleas returned to the original host, their reproductive output was higher than that of their ancestors. We conclude that the success of colonizing a novel host is (a) context-dependent and varies between flea and host species and (b) not accompanied by the loss of ability to exploit an ancestral host but may lead to an increase in this ability.
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Affiliation(s)
- Nadezhda A Stavtseva
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Laura J Fielden
- Biology Department, School of Science and Mathematics, Truman State University, Kirksville, Missouri, USA
| | - Irina S Khokhlova
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Boris R Krasnov
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
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15
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Beaurepaire A, Arredondo D, Genchi-García ML, Castelli L, Reynaldi FJ, Antunez K, Invernizzi C, Mondet F, Le Conte Y, Dalmon A. Genetic diversification of an invasive honey bee ectoparasite across sympatric and allopatric host populations. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 103:105340. [PMID: 35853582 DOI: 10.1016/j.meegid.2022.105340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/06/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Invasive parasites are major threats to biodiversity. The honey bee ectoparasite, Varroa destructor, has shifted host and spread almost globally several decades ago. This pest is generally considered to be the main global threat to Western honey bees, Apis mellifera, although the damages it causes are not equivalent in all its new host's populations. Due to the high virulence of this parasite and the viruses it vectors, beekeepers generally rely on acaricide treatments to keep their colonies alive. However, some populations of A. mellifera can survive without anthropogenic mite control, through the expression of diverse resistance and tolerance traits. Such surviving colonies are currently found throughout the globe, with the biggest populations being found in Sub-Saharan Africa and Latin America. Recently, genetic differences between mite populations infesting surviving and treated A. mellifera colonies in Europe were found, suggesting that adaptations of honey bees drive mite evolution. Yet, the prevalence of such co-evolutionary adaptations in other invasive populations of V. destructor remain unknown. Using the previous data from Europe and novel genetic data from V. destructor populations in South America and Africa, we here investigated whether mites display signs of adaptations to different host populations of diverse origins and undergoing differing management. Our results show that, contrary to the differences previously documented in Europe, mites infesting treated and untreated honey bee populations in Africa and South America are genetically similar. However, strong levels of genetic differentiation were found when comparing mites across continents, suggesting ongoing allopatric speciation despite a recent spread from genetically homogenous lineages. This study provides novel insights into the co-evolution of V. destructor and A. mellifera, and confirms that these species are ideal to investigate coevolution in newly established host-parasite systems.
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Affiliation(s)
- Alexis Beaurepaire
- INRAE, UR Abeilles et Environnement, Avignon, France; Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland; Agroscope, Swiss Bee Research Centre, Bern, Switzerland.
| | - Daniela Arredondo
- Department of Microbiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - María Laura Genchi-García
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland; Agroscope, Swiss Bee Research Centre, Bern, Switzerland; Instituto Multidisciplinario de Biología Celular, La Plata, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Loreley Castelli
- Department of Microbiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Francisco Jose Reynaldi
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Laboratorio de Virología, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Karina Antunez
- Department of Microbiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Ciro Invernizzi
- Facultad de Ciencias, Universidad de la República de Uruguay, Montevideo, Uruguay
| | - Fanny Mondet
- INRAE, UR Abeilles et Environnement, Avignon, France
| | - Yves Le Conte
- INRAE, UR Abeilles et Environnement, Avignon, France
| | - Anne Dalmon
- INRAE, UR Abeilles et Environnement, Avignon, France
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16
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The scale of competition impacts parasite virulence evolution. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10199-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Glonti T, Pirnay JP. In Vitro Techniques and Measurements of Phage Characteristics That Are Important for Phage Therapy Success. Viruses 2022; 14:1490. [PMID: 35891470 PMCID: PMC9323186 DOI: 10.3390/v14071490] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/18/2022] [Accepted: 07/05/2022] [Indexed: 01/27/2023] Open
Abstract
Validated methods for phage selection, host range expansion, and lytic activity determination are indispensable for maximizing phage therapy outcomes. In this review, we describe some relevant methods, highlighting their advantages and disadvantages, and categorize them as preliminary or confirmatory methods where appropriate. Experimental conditions, such as the composition and consistency of culture media, have an impact on bacterial growth and, consequently, phage propagation and the selection of phage-resistant mutants. The phages require different experimental conditions to be tested to fully reveal their characteristics and phage therapy potential in view of their future use in therapy. Phage lytic activity or virulence should be considered as a result of the phage, its host, and intracellular/environmental factors, including the ability of a phage to recognize receptors on the bacterial cell surface. In vitro quantitative and qualitative measurements of phage characteristics, further validated by in vivo experiments, could be incorporated into one system or mathematical model/formula, which could predict a potential successful outcome of clinical applications.
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Affiliation(s)
- Tea Glonti
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, B-1120 Brussels, Belgium;
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18
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Lutermann H. Socializing in an Infectious World: The Role of Parasites in Social Evolution of a Unique Rodent Family. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.879031] [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
Transmission of parasites between hosts is facilitated by close contact of hosts. Consequently, parasites have been proposed as an important constraint to the evolution of sociality accounting for its rarity. Despite the presumed costs associated with parasitism, the majority of species of African mole-rats (Family: Bathyergidae) are social. In fact, only the extremes of sociality (i.e., solitary and singular breeding) are represented in this subterranean rodent family. But how did bathyergids overcome the costs of parasitism? Parasite burden is a function of the exposure and susceptibility of a host to parasites. In this review I explore how living in sealed burrow systems and the group defenses that can be employed by closely related group members can effectively reduce the exposure and susceptibility of social bathyergids to parasites. Evidence suggests that this can be achieved largely by investment in relatively cheap and flexible behavioral rather than physiological defense mechanisms. This also shifts the selection pressure for parasites on successful transmission between group members rather than transmission between groups. In turn, this constrains the evolution of virulence and favors socially transmitted parasites (e.g., mites and lice) further reducing the costs of parasitism for social Bathyergidae. I conclude by highlighting directions for future research to evaluate the mechanisms proposed and to consider parasites as facilitators of social evolution not only in this rodent family but also other singular breeders.
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19
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Khokhlova IS, van der Mescht L, Warburton EM, Stavtseva NA, Krasnov BR. Adaptation to a novel host and performance trade-off in host-generalist and host-specific insect ectoparasites. INSECT SCIENCE 2022; 29:567-580. [PMID: 34048132 DOI: 10.1111/1744-7917.12929] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 04/01/2021] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
We investigated the performance trade-offs of fleas (Siphonaptera) while adapting to a novel host using two host generalists (Xenopsylla conformis and Xenopsylla ramesis) and one host specialist (Parapulex chephrenis) maintained on their principal hosts (Meriones crassus for Xenopsylla and Acomys cahirinus for P. chephrenis). We asked whether, over generations, (i) a host generalist may become a specialist by evolving the ability to exploit a novel host and losing the ability to exploit an original host and (ii) a host specialist can become a generalist by evolving the ability to exploit a novel host without losing the ability to exploit an original host. We established an experimental line of each species on a novel host (Acomys russatus for Xenopsylla and M. crassus for P. chephrenis) and maintained this line on this host during 23 generations. We compared reproductive performance of progenitors of each line and their descendants when they exploited either original or novel host in terms of egg number and size, hatching success, offspring production, and offspring size. We found changes in performance over generations in female offspring size only. Xenopsylla conformis demonstrated a tendency to become a host specialist (increased performance on the novel host with a concomitant decreased performance on the original host), whereas P. chephrenis demonstrated a tendency to become a host generalist (increased performance on the novel host without a concomitant decreased performance on the original host). We conclude that the probability of generalist to specialist transition, and vice versa, is context-dependent and varies between species.
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Affiliation(s)
- Irina S Khokhlova
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Luther van der Mescht
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
- Present affiliation and address of Luther van der Mescht: Clinvet International, Uitzich Road, Bainsvlei, 9338 Bloemfontein, Free State, South Africa
| | - Elizabeth M Warburton
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
- Present affiliation and address of Elizabeth M. Warburton: Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, 203 D.W. Brooks Dr., Athens, GA, 30602, USA
| | - Nadezhda A Stavtseva
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
| | - Boris R Krasnov
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
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20
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Pinilla-Gallego MS, Irwin RE. Effects of an alternative host on the prevalence and intensity of infection of a bumble bee parasite. Parasitology 2022; 149:562-567. [PMID: 35067238 PMCID: PMC10090601 DOI: 10.1017/s003118202200004x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/16/2021] [Accepted: 01/09/2022] [Indexed: 11/06/2022]
Abstract
Several bee parasites are transmitted through flowers, and some of them can infect multiple host species. Given the shared use of flowers by bee species, parasites can potentially encounter multiple host species, which could affect the evolution of parasite virulence. We used the trypanosomatid parasite Crithidia bombi and its host, the common eastern bumble bee (Bombus impatiens), to explore the effect of infecting an alternative host, the alfalfa leaf-cutter bee (Megachile rotundata), on parasite infectivity and ability to replicate. We conducted a serial passage experiment on primary and alternative hosts, assessing infectivity and intensity of infection during five passes. Parasite cells from each pass through the alternative host were also used to infect a group of primary hosts. We found that serial passes through the alternative host increased infectivity, but there was no effect on intensity of infection. Interestingly, both the probability and intensity of infection on the primary host increased after serial passage through the alternative host. This increase in intensity of infection could be due to maladaptation after selection of new C. bombi strains has occurred in the alternative host. This study suggests that host switching has the potential to affect the adaptation of bee parasites to their hosts.
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Affiliation(s)
| | - Rebecca E. Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC27695, USA
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21
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Pulkkinen K, Ketola T, Laakso J, Mappes J, Sundberg L. Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen. Evol Appl 2022; 15:417-428. [PMID: 35386393 PMCID: PMC8965373 DOI: 10.1111/eva.13355] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 01/27/2022] [Accepted: 02/01/2022] [Indexed: 12/05/2022] Open
Abstract
Phenotypic variation is suggested to facilitate the persistence of environmentally growing pathogens under environmental change. Here, we hypothesized that the intensive farming environment induces higher phenotypic variation in microbial pathogens than natural environment, because of high stochasticity for growth and stronger survival selection compared to the natural environment. We tested the hypothesis with an opportunistic fish pathogen Flavobacterium columnare isolated either from fish farms or from natural waters. We measured growth parameters of two morphotypes from all isolates in different resource concentrations and two temperatures relevant for the occurrence of disease epidemics at farms and tested their virulence using a zebrafish (Danio rerio) infection model. According to our hypothesis, isolates originating from the fish farms had higher phenotypic variation in growth between the morphotypes than the isolates from natural waters. The difference was more pronounced in higher resource concentrations and the higher temperature, suggesting that phenotypic variation is driven by the exploitation of increased outside-host resources at farms. Phenotypic variation of virulence was not observed based on isolate origin but only based on morphotype. However, when in contact with the larger fish, the less virulent morphotype of some of the isolates also had high virulence. As the less virulent morphotype also had higher growth rate in outside-host resources, the results suggest that both morphotypes can contribute to F. columnare epidemics at fish farms, especially with current prospects of warming temperatures. Our results suggest that higher phenotypic variation per se does not lead to higher virulence, but that environmental conditions at fish farms could select isolates with high phenotypic variation in bacterial population and hence affect evolution in F. columnare at fish farms. Our results highlight the multifaceted effects of human-induced environmental alterations in shaping epidemiology and evolution in microbial pathogens.
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Affiliation(s)
- Katja Pulkkinen
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Tarmo Ketola
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Jouni Laakso
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of HelsinkiHelsinkiFinland
| | - Johanna Mappes
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of HelsinkiHelsinkiFinland
| | - Lotta‐Riina Sundberg
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
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22
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Host Manipulation Mechanisms of SARS-CoV-2. Acta Biotheor 2021; 70:4. [PMID: 34902063 PMCID: PMC8667538 DOI: 10.1007/s10441-021-09425-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/16/2021] [Indexed: 10/28/2022]
Abstract
Viruses are the simplest of pathogens, but possess sophisticated molecular mechanisms to manipulate host behavior, frequently utilizing molecular mimicry. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to bind to the host receptor neuropilin-1 in order to gain entry into the cell. To do this, the virus utilizes its spike protein polybasic cleavage site (PCS), which mimics the CendR motif of neuropilin-1's endogenous ligands. In addition to facilitating cell entry, binding to neuropilin-1 has analgesic effects. We discuss the potential impact of neuropilin-1 binding by SARS-CoV-2 in ameliorating sickness behavior of the host, and identify a convergent evolutionary strategy of PCS cleavage and subsequent neuropilin binding in other human viruses. In addition, we discuss the evolutionary leap of the ancestor of SARS-COV-2, which involved acquisition of the PCS thus faciliting binding to the neuropilin-1 receptor. Acquisition of the PCS by the ancestor of SARS-CoV-2 appears to have led to pleiotropic beneficial effects including enhancement of cell entry via binding to ACE2, facilitation of cell entry via binding to neuropilin-1, promotion of analgesia, and potentially the formation of decoy epitopes via enhanced shedding of the S1 subunit. Lastly, other potential neuromanipulation strategies employed by SARS-CoV-2 are discussed, including interferon suppression and the resulting reduction in sickness behavior, enhanced transmission through neurally mediated cough induction, and reduction in sense of smell.
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23
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Alizon S, Sofonea MT. SARS-CoV-2 virulence evolution: Avirulence theory, immunity and trade-offs. J Evol Biol 2021; 34:1867-1877. [PMID: 34196431 PMCID: PMC8447366 DOI: 10.1111/jeb.13896] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/15/2021] [Accepted: 06/21/2021] [Indexed: 12/21/2022]
Abstract
The COVID-19 pandemic has led to a resurgence of the debate on whether host-parasite interactions should evolve towards avirulence. In this review, we first show that SARS-CoV-2 virulence is evolving, before explaining why some expect the mortality caused by the epidemic to converge towards that of human seasonal alphacoronaviruses. Leaning on existing theory, we then include viral evolution into the picture and discuss hypotheses explaining why the virulence has increased since the beginning of the pandemic. Finally, we mention some potential scenarios for the future.
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Affiliation(s)
- Samuel Alizon
- MIVEGECCNRS, IRD, Univ. MontpellierMontpellierFrance
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24
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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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25
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Farrell MJ, Park AW, Cressler CE, Dallas T, Huang S, Mideo N, Morales-Castilla I, Davies TJ, Stephens P. The ghost of hosts past: impacts of host extinction on parasite specificity. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200351. [PMID: 34538147 PMCID: PMC8450631 DOI: 10.1098/rstb.2020.0351] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2021] [Indexed: 11/29/2022] Open
Abstract
A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host-parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity. This article is part of the theme issue 'Infectious disease macroecology: parasite diversity and dynamics across the globe'.
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Affiliation(s)
- Maxwell J. Farrell
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | | | - Clayton E. Cressler
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Tad Dallas
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70806, USA
- Department of Biological Sciences, University of South Carolina, Columbia, SC, 29208, USA
| | - Shan Huang
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
| | - Nicole Mideo
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Ignacio Morales-Castilla
- Universidad de Alcalá, GloCEE - Global Change Ecology and Evolution Research Group, Departamento de Ciencias de la Vida, 28805 Alcalá de Henares, Madrid, Spain
| | - T. Jonathan Davies
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Department of Botany and Plant Biotechnology, African Centre for DNA Barcoding, University of Johannesburg, Johannesburg 2092, South Africa
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26
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Schmid-Hempel P. Sociality and parasite transmission. Behav Ecol Sociobiol 2021; 75:156. [PMID: 34720348 PMCID: PMC8540878 DOI: 10.1007/s00265-021-03092-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/23/2021] [Accepted: 09/27/2021] [Indexed: 11/18/2022]
Abstract
Parasites and their social hosts form many different relationships. But what kind of selection regimes are important? A look at the parameters that determine fitness of the two parties suggests that social hosts differ from solitary ones primarily in the structure of transmission pathways. Because transmission is, both, the physical encounter of a new host and infecting it, several different elements determine parasite transmission success. These include spatial distance, genetic distance, or the temporal and ecological niche overlaps. Combing these elements into a ‘generalized transmission distance’ that determines parasite fitness aids in the identification of the critical steps. For example, short-distance transmission to genetically similar hosts within the social group is the most frequent process under sociality. Therefore, spatio-genetical distances are the main driver of parasite fitness. Vice versa, the generalized distance identifies the critical host defences. In this case, host defences should be primarily selected to defend against the within-group spread of an infection, especially among closely related group members.
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Affiliation(s)
- Paul Schmid-Hempel
- Institute of Integrative Biology (IBZ), ETH Zürich, ETH-Zentrum CHN, Universitätstrasse 16, CH-8092 Zürich, Switzerland
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27
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Gomez-Chamorro A, Hodžić A, King KC, Cabezas-Cruz A. Ecological and evolutionary perspectives on tick-borne pathogen co-infections. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2021; 1:100049. [PMID: 35284886 PMCID: PMC8906131 DOI: 10.1016/j.crpvbd.2021.100049] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/09/2021] [Accepted: 09/16/2021] [Indexed: 06/14/2023]
Abstract
Tick-borne pathogen co-infections are common in nature. Co-infecting pathogens interact with each other and the tick microbiome, which influences individual pathogen fitness, and ultimately shapes virulence, infectivity, and transmission. In this review, we discuss how tick-borne pathogens are an ideal framework to study the evolutionary dynamics of co-infections. We highlight the importance of inter-species and intra-species interactions in vector-borne pathogen ecology and evolution. We also propose experimental evolution in tick cell lines as a method to directly test the impact of co-infections on pathogen evolution. Experimental evolution can simulate in real-time the long periods of time involved in within-vector pathogen interactions in nature, a major practical obstacle to cracking the influence of co-infections on pathogen evolution and ecology.
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Affiliation(s)
- Andrea Gomez-Chamorro
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK
- Anses, INRAE, Ecole Nationale Vétérinaire D’Alfort, UMR BIPAR, Laboratoire de Santé Animale, Maisons-Alfort, F-94700, France
| | - Adnan Hodžić
- Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Kayla C. King
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, UK
| | - Alejandro Cabezas-Cruz
- Anses, INRAE, Ecole Nationale Vétérinaire D’Alfort, UMR BIPAR, Laboratoire de Santé Animale, Maisons-Alfort, F-94700, France
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28
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Middlebrook EA, Stark DL, Cornwall DH, Kubinak JL, Potts WK. Deep Sequencing of MHC-Adapted Viral Lines Reveals Complex Recombinational Exchanges With Endogenous Retroviruses Leading to High-Frequency Variants. Front Genet 2021; 12:716623. [PMID: 34512727 PMCID: PMC8430262 DOI: 10.3389/fgene.2021.716623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/05/2021] [Indexed: 12/03/2022] Open
Abstract
Experimental evolution (serial passage) of Friend virus complex (FVC) in mice demonstrates phenotypic adaptation to specific host major histocompatibility complex (MHC) genotypes. These evolved viral lines show increased fitness and virulence in their host-genotype-of-passage, but display fitness and virulence tradeoffs when infecting unfamiliar host MHC genotypes. Here, we deep sequence these viral lines in an attempt to discover the genetic basis of FVC adaptation. The principal prediction for genotype-specific adaptation is that unique mutations would rise to high frequency in viral lines adapted to each host MHC genotype. This prediction was not supported by our sequencing data as most observed high-frequency variants were present in each of our independently evolved viral lines. However, using a multi-variate approach to measure divergence between viral populations, we show that populations of replicate evolved viral lines from the same MHC congenic mouse strain were more similar to one another than to lines derived from different MHC congenic mouse strains, suggesting that MHC genotype does predictably act on viral evolution in our model. Sequence analysis also revealed rampant recombination with endogenous murine leukemia virus sequences (EnMuLVs) that are encoded within the BALB/c mouse genome. The highest frequency variants in all six lines contained a 12 bp insertion from a recombinant EnMuLV source, suggesting such recombinants were either being favored by selection or were contained in a recombinational hotspot. Interestingly, they did not reach fixation, as if they are low fitness. The amount of background mutations linked to FVC/EnMuLV variable sites indicated that FVC/EnMuLV recombinants had not reached mutation selection equilibrium and thus, that EnMuLV sequences are likely continuously introgressing into the replicating viral population. These discoveries raise the question: is the expression of EnMuLV sequences in mouse splenocytes that permit recombination with exogenous FVC a pathogen or host adaptation?
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Affiliation(s)
- Earl A. Middlebrook
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
- Biosecurity and Public Health, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Derek L. Stark
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
| | - Douglas H. Cornwall
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
- Department of Pathology, University of Utah, Salt Lake City, UT, United States
| | - Jason L. Kubinak
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Wayne K. Potts
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
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29
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Gopalan-Nair R, Jardinaud MF, Legrand L, Landry D, Barlet X, Lopez-Roques C, Vandecasteele C, Bouchez O, Genin S, Guidot A. Convergent Rewiring of the Virulence Regulatory Network Promotes Adaptation of Ralstonia solanacearum on Resistant Tomato. Mol Biol Evol 2021; 38:1792-1808. [PMID: 33306125 PMCID: PMC8097285 DOI: 10.1093/molbev/msaa320] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The evolutionary and adaptive potential of a pathogen is a key determinant for successful host colonization and proliferation but remains poorly known for most of the pathogens. Here, we used experimental evolution combined with phenotyping, genomics, and transcriptomics to estimate the adaptive potential of the bacterial plant pathogen Ralstonia solanacearum to overcome the quantitative resistance of the tomato cultivar Hawaii 7996. After serial passaging over 300 generations, we observed pathogen adaptation to within-plant environment of the resistant cultivar but no plant resistance breakdown. Genomic sequence analysis of the adapted clones revealed few genetic alterations, but we provide evidence that all but one were gain of function mutations. Transcriptomic analyses revealed that even if different adaptive events occurred in independently evolved clones, there is convergence toward a global rewiring of the virulence regulatory network as evidenced by largely overlapping gene expression profiles. A subset of four transcription regulators, including HrpB, the activator of the type 3 secretion system regulon and EfpR, a global regulator of virulence and metabolic functions, emerged as key nodes of this regulatory network that are frequently targeted to redirect the pathogen’s physiology and improve its fitness in adverse conditions. Significant transcriptomic variations were also detected in evolved clones showing no genomic polymorphism, suggesting that epigenetic modifications regulate expression of some of the virulence network components and play a major role in adaptation as well.
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Affiliation(s)
| | | | - Ludovic Legrand
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - David Landry
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Xavier Barlet
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | | | | | - Olivier Bouchez
- GeT-PlaGe, Genotoul, INRAE, US 1426, Castanet-Tolosan, France
| | - Stéphane Genin
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Alice Guidot
- LIPME, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
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30
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Merryman M, Crigler J, Seipelt-Thiemann R, McClelland E. A mutation in C. neoformans mitochondrial NADH dehydrogenase results in increased virulence in mice. Virulence 2021; 11:1366-1378. [PMID: 33103620 PMCID: PMC7588220 DOI: 10.1080/21505594.2020.1831332] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cryptococcus neoformans: (H99W) was serially passaged in the invertebrate wax moth Galleria mellonella fifteen times to study how fungal virulence evolves under selection and whether those adaptations affect virulence. The G. mellonella passaged strain (P15) and the pre-passage H99W strains were used to infect three different host models of C. neoformans: C. elegans, G. mellonella, and Balb/c mice. While there was no difference in survival in the invertebrate models, P15 killed mice faster than H99W through both intratracheal and intravenous routes of infection and mice infected intravenously with P15 showed higher fungal burden in the brain. Characterization of the major virulence factors of C. neoformans found that P15 had increased capsule size, GXM release, and melanization. Whole genome sequencing of P15 and H99W revealed two mutations in P15, an insertion in the promoter region of NADH dehydrogenase (CNAG_09000) and an insertion in the LMP1 gene (CNAG_06765). Both ATP production and metabolic rate were higher in P15 compared to H99W. Quantitative RT-PCR suggested that the increased ATP was due to increased RNA levels of NADH dehydrogenase. Thus, adaptation to growth in hemocytes resulted in increased production of ATP, increased metabolic rate, and increased virulence in mice. This was likely due to differential expression of virulence factors, which skewed the host immune response to a less efficient Th2 response, with higher levels of IL-4, IL-10, and TNF-α in the brain. Overall, serial passage experiments have increased our understanding of how this yeast evolves under innate immune selection pressure.
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Affiliation(s)
- Mitch Merryman
- Department of Biology, Middle Tennessee State University , Murfreesboro, TN, USA
| | - Jacob Crigler
- Department of Biology, Middle Tennessee State University , Murfreesboro, TN, USA
| | | | - Erin McClelland
- Department of Biology, Middle Tennessee State University , Murfreesboro, TN, USA.,M&P Associates , Murfreesboro, TN, USA
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31
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Fang K, Zhou J, Chen L, Li YX, Yang AL, Dong XF, Zhang HB. Virulence and community dynamics of fungal species with vertical and horizontal transmission on a plant with multiple infections. PLoS Pathog 2021; 17:e1009769. [PMID: 34265026 PMCID: PMC8315517 DOI: 10.1371/journal.ppat.1009769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 07/27/2021] [Accepted: 06/29/2021] [Indexed: 01/04/2023] Open
Abstract
The virulence evolution of multiple infections of parasites from the same species has been modeled widely in evolution theory. However, experimental studies on this topic remain scarce, particularly regarding multiple infections by different parasite species. Here, we characterized the virulence and community dynamics of fungal pathogens on the invasive plant Ageratina adenophora to verify the predictions made by the model. We observed that A. adenophora was highly susceptible to diverse foliar pathogens with mixed vertical and horizontal transmission within leaf spots. The transmission mode mainly determined the pathogen community structure at the leaf spot level. Over time, the pathogen community within a leaf spot showed decreased Shannon diversity; moreover, the vertically transmitted pathogens exhibited decreased virulence to the host A. adenophora, but the horizontally transmitted pathogens exhibited increased virulence to the host. Our results demonstrate that the predictions of classical models for the virulence evolution of multiple infections are still valid in a complex realistic environment and highlight the impact of transmission mode on disease epidemics of foliar fungal pathogens. We also propose that seedborne fungi play an important role in structuring the foliar pathogen community from multiple infections within a leaf spot. A growing number of examples indicate that many plant diseases are caused by multiple taxa of microbes. Therefore, how virulence evolves in the context of multiple infections by different species with both vertical and horizontal transmission modes represents an important area of pathogen ecology and evolution, but there is a lack of experimental study. Here, we employ a naturally occurring host-parasite system, the invasive plant Ageratina adenophora and its foliar pathogens, to verify that theoretical predictions of classical models for virulence evolution are still valid in a complex realistic environment, i.e., the transmission mode determines the dynamics of the virulence and pathogen community under multiple infections. Moreover, we propose that seedborne fungi are important in structuring the foliar pathogen community consisting of multiple infections within a leaf spot. Our findings provide valuable information for understanding how multiple infections affect the key components, i.e., the virulence evolution and pathogen community dynamics, of host-pathogen interactions in the field.
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Affiliation(s)
- Kai Fang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- School of Ecology and Environmental Science, Yunnan University, Kunming, China
| | - Jie Zhou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
| | - Lin Chen
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- School of Ecology and Environmental Science, Yunnan University, Kunming, China
| | - Yu-Xuan Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
| | - Ai-Ling Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
| | - Xing-Fan Dong
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
| | - Han-Bo Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- School of Ecology and Environmental Science, Yunnan University, Kunming, China
- * E-mail:
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32
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Ameline C, Bourgeois Y, Vögtli F, Savola E, Andras J, Engelstädter J, Ebert D. A Two-Locus System with Strong Epistasis Underlies Rapid Parasite-Mediated Evolution of Host Resistance. Mol Biol Evol 2021; 38:1512-1528. [PMID: 33258959 PMCID: PMC8042741 DOI: 10.1093/molbev/msaa311] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Parasites are a major evolutionary force, driving adaptive responses in host populations. Although the link between phenotypic response to parasite-mediated natural selection and the underlying genetic architecture often remains obscure, this link is crucial for understanding the evolution of resistance and predicting associated allele frequency changes in the population. To close this gap, we monitored the response to selection during epidemics of a virulent bacterial pathogen, Pasteuria ramosa, in a natural host population of Daphnia magna. Across two epidemics, we observed a strong increase in the proportion of resistant phenotypes as the epidemics progressed. Field and laboratory experiments confirmed that this increase in resistance was caused by selection from the local parasite. Using a genome-wide association study, we built a genetic model in which two genomic regions with dominance and epistasis control resistance polymorphism in the host. We verified this model by selfing host genotypes with different resistance phenotypes and scoring their F1 for segregation of resistance and associated genetic markers. Such epistatic effects with strong fitness consequences in host–parasite coevolution are believed to be crucial in the Red Queen model for the evolution of genetic recombination.
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Affiliation(s)
- Camille Ameline
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Yann Bourgeois
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,School of Biological Sciences, University of Portsmouth, Portsmouth, United Kingdom
| | - Felix Vögtli
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Eevi Savola
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,Institute of Evolutionary Biology, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Jason Andras
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,Department of Biological Sciences, Clapp Laboratory, Mount Holyoke College, South Hadley, MA, USA
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
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33
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Host genotype and genetic diversity shape the evolution of a novel bacterial infection. THE ISME JOURNAL 2021; 15:2146-2157. [PMID: 33603148 PMCID: PMC8245636 DOI: 10.1038/s41396-021-00911-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 01/10/2021] [Accepted: 01/25/2021] [Indexed: 01/31/2023]
Abstract
Pathogens continue to emerge from increased contact with novel host species. Whilst these hosts can represent distinct environments for pathogens, the impacts of host genetic background on how a pathogen evolves post-emergence are unclear. In a novel interaction, we experimentally evolved a pathogen (Staphylococcus aureus) in populations of wild nematodes (Caenorhabditis elegans) to test whether host genotype and genetic diversity affect pathogen evolution. After ten rounds of selection, we found that pathogen virulence evolved to vary across host genotypes, with differences in host metal ion acquisition detected as a possible driver of increased host exploitation. Diverse host populations selected for the highest levels of pathogen virulence, but infectivity was constrained, unlike in host monocultures. We hypothesise that population heterogeneity might pool together individuals that contribute disproportionately to the spread of infection or to enhanced virulence. The genomes of evolved populations were sequenced, and it was revealed that pathogens selected in distantly-related host genotypes diverged more than those in closely-related host genotypes. S. aureus nevertheless maintained a broad host range. Our study provides unique empirical insight into the evolutionary dynamics that could occur in other novel infections of wildlife and humans.
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34
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Conlon BH, Gostinčar C, Fricke J, Kreuzenbeck NB, Daniel JM, Schlosser MS, Peereboom N, Aanen DK, de Beer ZW, Beemelmanns C, Gunde-Cimerman N, Poulsen M. Genome reduction and relaxed selection is associated with the transition to symbiosis in the basidiomycete genus Podaxis. iScience 2021; 24:102680. [PMID: 34189441 PMCID: PMC8220239 DOI: 10.1016/j.isci.2021.102680] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/07/2021] [Accepted: 05/28/2021] [Indexed: 11/29/2022] Open
Abstract
Insights into the genomic consequences of symbiosis for basidiomycete fungi associated with social insects remain sparse. Capitalizing on viability of spores from centuries-old herbarium specimens of free-living, facultative, and specialist termite-associated Podaxis fungi, we obtained genomes of 10 specimens, including two type species described by Linnaeus >240 years ago. We document that the transition to termite association was accompanied by significant reductions in genome size and gene content, accelerated evolution in protein-coding genes, and reduced functional capacities for oxidative stress responses and lignin degradation. Functional testing confirmed that termite specialists perform worse under oxidative stress, while all lineages retained some capacity to cleave lignin. Mitochondrial genomes of termite associates were significantly larger; possibly driven by smaller population sizes or reduced competition, supported by apparent loss of certain biosynthetic gene clusters. Our findings point to relaxed selection that mirrors genome traits observed among obligate endosymbiotic bacteria of many insects.
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Affiliation(s)
- Benjamin H. Conlon
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark
| | - Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Janis Fricke
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoll-Institute, Chemical Biology, 07745 Jena, Germany
| | - Nina B. Kreuzenbeck
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoll-Institute, Chemical Biology, 07745 Jena, Germany
| | - Jan-Martin Daniel
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoll-Institute, Chemical Biology, 07745 Jena, Germany
| | - Malte S.L. Schlosser
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark
| | - Nils Peereboom
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark
| | - Duur K. Aanen
- Department of Plant Sciences, Laboratory of Genetics, Wageningen University, 6708 PB Wageningen, the Netherlands
| | - Z. Wilhelm de Beer
- Department of Biochemistry, Genetics, and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, South Africa
| | - Christine Beemelmanns
- Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoll-Institute, Chemical Biology, 07745 Jena, Germany
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Michael Poulsen
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark
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35
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Bruns EL, Antonovics J, Hood ME. From generalist to specialists: Variation in the host range and performance of anther-smut pathogens on Dianthus. Evolution 2021; 75:2494-2508. [PMID: 33983636 DOI: 10.1111/evo.14264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/05/2021] [Accepted: 04/24/2021] [Indexed: 12/22/2022]
Abstract
Determining the processes that drive the evolution of pathogen host range can inform our understanding of disease dynamics and the potential for host shifts. In natural populations, patterns of host range could be driven by genetically based differences in pathogen infectivity or ecological differences in host availability. In northwestern Italy, four reproductively isolated lineages of the fungal plant-pathogen Microbotryum have been shown to co-occur on several species in the genus Dianthus. We carried out cross-inoculation experiments to determine whether patterns of realized host range in these four lineages were driven by differences in infectivity and to test whether there was evidence of a trade-off between host range and within-host reproduction. We found strong concordance between field patterns of host range and pathogen infectivity on different Dianthus species using experimental inoculation, indicating that infection ability is a major driving force of host range. However, we found no evidence of a trade-off between the ability to infect a wider range of host species and spore production on a shared host.
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Affiliation(s)
- Emily L Bruns
- Current Address: Department of Biology, University of Maryland, College Park, Maryland, 20742
| | - Janis Antonovics
- Department of Biology, University of Virginia, Charlottesville, Virginia, 22904
| | - Michael E Hood
- Department of Biology, Amherst College, Amherst, Massachusetts, 01002
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36
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Wargo AR, Kurath G, Scott RJ, Kerr B. Virus shedding kinetics and unconventional virulence tradeoffs. PLoS Pathog 2021; 17:e1009528. [PMID: 33970967 PMCID: PMC8109835 DOI: 10.1371/journal.ppat.1009528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/03/2021] [Indexed: 11/19/2022] Open
Abstract
Tradeoff theory, which postulates that virulence provides both transmission costs and benefits for pathogens, has become widely adopted by the scientific community. Although theoretical literature exploring virulence-tradeoffs is vast, empirical studies validating various assumptions still remain sparse. In particular, truncation of transmission duration as a cost of virulence has been difficult to quantify with robust controlled in vivo studies. We sought to fill this knowledge gap by investigating how transmission rate and duration were associated with virulence for infectious hematopoietic necrosis virus (IHNV) in rainbow trout (Oncorhynchus mykiss). Using host mortality to quantify virulence and viral shedding to quantify transmission, we found that IHNV did not conform to classical tradeoff theory. More virulent genotypes of the virus were found to have longer transmission durations due to lower recovery rates of infected hosts, but the relationship was not saturating as assumed by tradeoff theory. Furthermore, the impact of host mortality on limiting transmission duration was minimal and greatly outweighed by recovery. Transmission rate differences between high and low virulence genotypes were also small and inconsistent. Ultimately, more virulent genotypes were found to have the overall fitness advantage, and there was no apparent constraint on the evolution of increased virulence for IHNV. However, using a mathematical model parameterized with experimental data, it was found that host culling resurrected the virulence tradeoff and provided low virulence genotypes with the advantage. Human-induced or natural culling, as well as host population fragmentation, may be some of the mechanisms by which virulence diversity is maintained in nature. This work highlights the importance of considering non-classical virulence tradeoffs.
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Affiliation(s)
- Andrew R. Wargo
- Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, United States of America
| | - Gael Kurath
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, Washington, United States of America
| | - Robert J. Scott
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Benjamin Kerr
- Department of Biology, University of Washington, Seattle, Washington, United States of America
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37
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Hawley DM, Gibson AK, Townsend AK, Craft ME, Stephenson JF. Bidirectional interactions between host social behaviour and parasites arise through ecological and evolutionary processes. Parasitology 2021; 148:274-288. [PMID: 33092680 PMCID: PMC11010184 DOI: 10.1017/s0031182020002048] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 02/07/2023]
Abstract
An animal's social behaviour both influences and changes in response to its parasites. Here we consider these bidirectional links between host social behaviours and parasite infection, both those that occur from ecological vs evolutionary processes. First, we review how social behaviours of individuals and groups influence ecological patterns of parasite transmission. We then discuss how parasite infection, in turn, can alter host social interactions by changing the behaviour of both infected and uninfected individuals. Together, these ecological feedbacks between social behaviour and parasite infection can result in important epidemiological consequences. Next, we consider the ways in which host social behaviours evolve in response to parasites, highlighting constraints that arise from the need for hosts to maintain benefits of sociality while minimizing fitness costs of parasites. Finally, we consider how host social behaviours shape the population genetic structure of parasites and the evolution of key parasite traits, such as virulence. Overall, these bidirectional relationships between host social behaviours and parasites are an important yet often underappreciated component of population-level disease dynamics and host-parasite coevolution.
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Affiliation(s)
- Dana M. Hawley
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA24061, USA
| | - Amanda K. Gibson
- Department of Biology, University of Virginia, Charlottesville, VA22903, USA
| | | | - Meggan E. Craft
- Department of Veterinary Population Medicine and Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN55108, USA
| | - Jessica F. Stephenson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA15260, USA
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Brown CR, Hannebaum SL, O’Brien VA, Page CE, Rannala B, Roche EA, Wagnon GS, Knutie SA, Moore AT, Brown MB. The cost of ectoparasitism in Cliff Swallows declines over 35 years. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1446] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Charles R. Brown
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Stacey L. Hannebaum
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Valerie A. O’Brien
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Catherine E. Page
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Bruce Rannala
- Department of Evolution and Ecology University of California Davis California 95616 USA
| | - Erin A. Roche
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Gigi S. Wagnon
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Sarah A. Knutie
- Department of Ecology and Evolutionary Biology University of Connecticut 75 N. Eagleville Rd. Storrs Connecticut 06269 USA
| | - Amy T. Moore
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
| | - Mary B. Brown
- Department of Biological Sciences University of Tulsa 800 S. Tucker Dr. Tulsa Oklahoma 74104 USA
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Stavtseva NA, Fielden LJ, Khokhlova IS, Warburton EM, van der Mescht L, Krasnov BR. Colonization of a novel host by fleas: changes in egg production and egg size. Parasitol Res 2021; 120:451-459. [PMID: 33447886 DOI: 10.1007/s00436-021-07052-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 01/10/2021] [Indexed: 11/25/2022]
Abstract
We studied the success of fleas, Synosternus cleopatrae and Xenopsylla ramesis, in switching to a novel host by establishing experimental lines maintained on different hosts for 18 generations. Fleas fed on principal (P-line) or novel hosts, either sympatric with (S-line) or allopatric to (A-line) a flea and its principal host, then we assessed their reproductive performance via the number and size of eggs. We compared reproductive performance between hosts within a line and between lines within a host asking: (a) whether fleas adapt to a novel host species after multiple generations; (b) if yes, whether the pattern of adaptation differs between novel host species sympatric with or allopatric to a flea and its principal host; and (c) adaptation to a novel host is accompanied with a loss of success in exploitation of an original host. Fleas from the S- and A-lines increased their egg production on a novel host (except X. ramesis from the S-line). S. cleopatrae from the S-line but not the A-line increased egg size on a novel host, whereas X. ramesis from the A-line but not the S-line produced larger eggs from a novel host. We found no indication of a loss of reproductive performance on the original host while adapting to a novel host. We conclude that fleas are able to switch rapidly to a new host with the pattern of a switch to either sympatric or an allopatric host depending on the identities of both flea and host species.
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Affiliation(s)
- Nadezhda A Stavtseva
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer Campus, 8499000, Beersheba, Israel
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer Campus, 8499000, Beersheba, Israel
| | - Laura J Fielden
- Biology Department, School of Science and Mathematics, Truman State University, 100E, Normal Avenue, Kirksville, MO, 63501, USA
| | - Irina S Khokhlova
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer Campus, 8499000, Beersheba, Israel
| | - Elizabeth M Warburton
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer Campus, 8499000, Beersheba, Israel
- Center for the Ecology of Infectious Diseases, Odum School of Ecology, University of Georgia, 203 D.W. Brooks Dr., Athens, GA, 30602, USA
| | - Luther van der Mescht
- Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer Campus, 8499000, Beersheba, Israel
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer Campus, 8499000, Beersheba, Israel
- Clinvet International, Uitzich Road, Bainsvlei, Bloemfontein, Free State, 9338, South Africa
| | - Boris R Krasnov
- Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Sede Boqer Campus, 8499000, Beersheba, Israel.
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40
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Brunner JL, Olson DH, Gray MJ, Miller DL, Duffus AL. Global patterns of ranavirus detections. Facets (Ott) 2021. [DOI: 10.1139/facets-2020-0013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Ranaviruses are emerging pathogens of poikilothermic vertebrates. In 2015 the Global Ranavirus Reporting System (GRRS) was established as a centralized, open access, online database for reports of the presence (and absence) of ranavirus around the globe. The GRRS has multiple data layers (e.g., location, date, host(s) species, and methods of detection) of use to those studying the epidemiology, ecology, and evolution of this group of viruses. Here we summarize the temporal, spatial, diagnostic, and host-taxonomic patterns of ranavirus reports in the GRRS. The number, distribution, and host diversity of ranavirus reports have increased dramatically since the mid 1990s, presumably in response to increased interest in ranaviruses and the conservation of their hosts, and also the availability of molecular diagnostics. Yet there are clear geographic and taxonomic biases among the reports. We encourage ranavirus researchers to add their studies to the portal because such collation can provide collaborative opportunities and unique insights to our developing knowledge of this pathogen and the emerging infectious disease that it causes.
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Affiliation(s)
- Jesse L. Brunner
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Deanna H. Olson
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331-8550, USA
| | - Matthew J. Gray
- Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN 37996-4563, USA
| | - Debra L. Miller
- College of Veterinary Medicine, University of Tennessee Institute of Agriculture, Knoxville, TN 37996-4563, USA
| | - Amanda L.J. Duffus
- Department of Natural Sciences, Gordon State College, Barnesville, GA 30204, USA
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Conteh S, Kolasny J, Robbins YL, Pyana P, Büscher P, Musgrove J, Butler B, Lambert L, Gorres JP, Duffy PE. Dynamics and Outcomes of Plasmodium Infections in Grammomys surdaster ( Grammomys dolichurus) Thicket Rats versus Inbred Mice. Am J Trop Med Hyg 2020; 103:1893-1901. [PMID: 32815499 DOI: 10.4269/ajtmh.20-0183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Investigations of malaria infection are often conducted by studying rodent Plasmodium species in inbred laboratory mice, but the efficacy of vaccines or adjunctive therapies observed in these models often does not translate to protection in humans. This raises concerns that mouse malaria models do not recapitulate important features of human malaria infections. African woodland thicket rats (Grammomys surdaster) are the natural host for the rodent malaria parasite Plasmodium berghei and the suspected natural host for Plasmodium vinckei vinckei. Previously, we reported that thicket rats are highly susceptible to diverse rodent parasite species, including P. berghei, Plasmodium yoelii, and Plasmodium chabaudi chabaudi, and are a more stringent model to assess the efficacy of whole-sporozoite vaccines than laboratory mice. Here, we compare the course of infection and virulence with additional rodent Plasmodium species, including various strains of P. berghei, P. yoelii, P. chabaudi, and P. vinckei, in thicket rats versus laboratory mice. We present evidence that rodent malaria parasite growth typically differs between the natural versus nonnatural host; G. surdaster limit infection by multiple rodent malaria strains, delaying and reducing peak parasitemia compared with laboratory mice. The course of malaria infection in thicket rats varied depending on parasite species and strain, resulting in self-cure, chronic parasitemia, or rapidly lethal infection, thus offering a variety of rodent malaria models to study different clinical outcomes in the natural host.
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Affiliation(s)
- Solomon Conteh
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Jacqueline Kolasny
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Yvette L Robbins
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Pati Pyana
- Department of Parasitology, Institut National de Recherche Biomedicale (INRB), Kinshasa, Democratic Republic of the Congo
| | - Philippe Büscher
- Department of Biomedical Sciences, Unit of Parasite Diagnostics, Institute of Tropical Medicine, Antwerp, Belgium
| | - Javonn Musgrove
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Brandi Butler
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Lynn Lambert
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - John Patrick Gorres
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology (LMIV), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland
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Bonneaud C, Tardy L, Hill GE, McGraw KJ, Wilson AJ, Giraudeau M. Experimental evidence for stabilizing selection on virulence in a bacterial pathogen. Evol Lett 2020; 4:491-501. [PMID: 33312685 PMCID: PMC7719545 DOI: 10.1002/evl3.203] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 12/03/2022] Open
Abstract
The virulence‐transmission trade‐off hypothesis has provided a dominant theoretical basis for predicting pathogen virulence evolution, but empirical tests are rare, particularly at pathogen emergence. The central prediction of this hypothesis is that pathogen fitness is maximized at intermediate virulence due to a trade‐off between infection duration and transmission rate. However, obtaining sufficient numbers of pathogen isolates of contrasting virulence to test the shape of relationships between key pathogen traits, and doing so without the confounds of evolved host protective immunity (as expected at emergence), is challenging. Here, we inoculated 55 isolates of the bacterial pathogen, Mycoplasma gallisepticum, into non‐resistant house finches (Haemorhous mexicanus) from populations that have never been exposed to the disease. Isolates were collected over a 20‐year period from outbreak in disease‐exposed populations of house finches and vary markedly in virulence. We found a positive linear relationship between pathogen virulence and transmission rate to an uninfected sentinel, supporting the core assumption of the trade‐off hypothesis. Further, in support of the key prediction, there was no evidence for directional selection on a quantitative proxy of pathogen virulence and, instead, isolates of intermediate virulence were fittest. Surprisingly, however, the positive relationship between virulence and transmission rate was not underpinned by variation in pathogen load or replication rate as is commonly assumed. Our results indicate that selection favors pathogens of intermediate virulence at disease emergence in a novel host species, even when virulence and transmission are not linked to pathogen load.
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Affiliation(s)
- Camille Bonneaud
- Centre for Ecology and Conservation, Biosciences University of Exeter Penryn Cornwall TR10 9FE United Kingdom
| | - Luc Tardy
- Centre for Ecology and Conservation, Biosciences University of Exeter Penryn Cornwall TR10 9FE United Kingdom
| | - Geoffrey E Hill
- Department of Biological Sciences Auburn University Auburn Alabama 36849-5414, United States of America
| | - Kevin J McGraw
- School of Life Sciences Arizona State University Tempe Arizona 85287-4501, United States of America
| | - Alastair J Wilson
- Centre for Ecology and Conservation, Biosciences University of Exeter Penryn Cornwall TR10 9FE United Kingdom
| | - Mathieu Giraudeau
- Centre for Ecology and Conservation, Biosciences University of Exeter Penryn Cornwall TR10 9FE United Kingdom.,School of Life Sciences Arizona State University Tempe Arizona 85287-4501, United States of America
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43
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Attenuation Methods for Live Vaccines. Methods Mol Biol 2020. [PMID: 32959252 DOI: 10.1007/978-1-0716-0795-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
Vaccination was developed by Edward Jenner in 1796. Since then, vaccination and vaccine development research has been a hotspot of research in the scientific community. Various ways of vaccine development are successfully employed in mass production of vaccines. One of the most successful ways to generate vaccines is the method of virulence attenuation in pathogens. The attenuated strains of viruses, bacteria, and parasites are used as vaccines which elicit robust immune response and confers protection against virulent pathogens. This chapter brings together the most common and efficient ways of generating live attenuated vaccine strains in viruses, bacteria, and parasites.
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Serial Passage of Cryptococcus neoformans in Galleria mellonella Results in Increased Capsule and Intracellular Replication in Hemocytes, but Not Increased Resistance to Hydrogen Peroxide. Pathogens 2020; 9:pathogens9090732. [PMID: 32899539 PMCID: PMC7559301 DOI: 10.3390/pathogens9090732] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/04/2020] [Accepted: 09/04/2020] [Indexed: 12/27/2022] Open
Abstract
To gain insight into how pathogens adapt to new hosts, Cryptococcus neoformans (H99W) was serially passaged in Galleria mellonella. The phenotypic characteristics of the passaged strain (P15) and H99W were evaluated. P15 grew faster in hemolymph than H99W, in vitro and in vivo, suggesting that adaptation had occurred. However, P15 was more susceptible to hydrogen peroxide in vitro, killed fewer mouse macrophages, and had less fungal burden in human ex vivo macrophages than H99W. Analysis of gene expression changes during Galleria infection showed only a few different genes involved in the reactive oxygen species response. As P15 sheds more GXM than H99W, P15 may have adapted by downregulating hemocyte hydrogen peroxide production, possibly through increased capsular glucuronoxylomannan (GXM) shedding. Hemocytes infected with P15 produced less hydrogen peroxide, and hydrogen peroxide production in response to GXM-shedding mutants was correlated with shed GXM. Histopathological examination of infected larvae showed increased numbers and sizes of immune nodules for P15 compared to H99W, suggesting an enhanced, but functionally defective, response to P15. These results could explain why this infection model does not always correlate with murine models. Overall, C. neoformans’ serial passage in G. mellonella resulted in a better understanding of how this yeast evolves under selection.
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Visher E, Boots M. The problem of mediocre generalists: population genetics and eco-evolutionary perspectives on host breadth evolution in pathogens. Proc Biol Sci 2020; 287:20201230. [PMID: 32811306 PMCID: PMC7482275 DOI: 10.1098/rspb.2020.1230] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/22/2020] [Indexed: 01/29/2023] Open
Abstract
Many of our theories for the generation and maintenance of diversity in nature depend on the existence of specialist biotic interactions which, in host-pathogen systems, also shape cross-species disease emergence. As such, niche breadth evolution, especially in host-parasite systems, remains a central focus in ecology and evolution. The predominant explanation for the existence of specialization in the literature is that niche breadth is constrained by trade-offs, such that a generalist is less fit on any particular environment than a given specialist. This trade-off theory has been used to predict niche breadth (co)evolution in both population genetics and eco-evolutionary models, with the different modelling methods providing separate, complementary insights. However, trade-offs may be far from universal, so population genetics theory has also proposed alternate mechanisms for costly generalism, including mutation accumulation. However, these mechanisms have yet to be integrated into eco-evolutionary models in order to understand how the mechanism of costly generalism alters the biological and ecological circumstances predicted to maintain specialism. In this review, we outline how population genetics and eco-evolutionary models based on trade-offs have provided insights for parasite niche breadth evolution and argue that the population genetics-derived mutation accumulation theory needs to be better integrated into eco-evolutionary theory.
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Affiliation(s)
- Elisa Visher
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
| | - Mike Boots
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
- College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Ringgold Standard Institution, Penryn, Cornwall, UK
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46
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Tehel A, Streicher T, Tragust S, Paxton RJ. Experimental infection of bumblebees with honeybee-associated viruses: no direct fitness costs but potential future threats to novel wild bee hosts. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200480. [PMID: 32874644 PMCID: PMC7428241 DOI: 10.1098/rsos.200480] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/10/2020] [Indexed: 05/05/2023]
Abstract
Pathogen spillover represents an important cause of biodiversity decline. For wild bee species such as bumblebees, many of which are in decline, correlational data point towards viral spillover from managed honeybees as a potential cause. Yet, impacts of these viruses on wild bees are rarely evaluated. Here, in a series of highly controlled laboratory infection assays with well-characterized viral inocula, we show that three viral types isolated from honeybees (deformed wing virus genotype A, deformed wing virus genotype B and black queen cell virus) readily replicate within hosts of the bumblebee Bombus terrestris. Impacts of these honeybee-derived viruses - either injected or fed - on the mortality of B. terrestris workers were, however, negligible and probably dependent on host condition. Our results highlight the potential threat of viral spillover from honeybees to novel wild bee species, though they also underscore the importance of additional studies on this and other wild bee species under field-realistic conditions to evaluate whether pathogen spillover has a negative impact on wild bee individuals and population fitness.
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Affiliation(s)
- Anja Tehel
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
| | - Tabea Streicher
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
| | - Simon Tragust
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
| | - Robert J. Paxton
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany
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Gibson AK, Baffoe-Bonnie H, Penley MJ, Lin J, Owens R, Khalid A, Morran LT. The evolution of parasite host range in heterogeneous host populations. J Evol Biol 2020; 33:773-782. [PMID: 32086852 PMCID: PMC7275899 DOI: 10.1111/jeb.13608] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/24/2020] [Accepted: 02/11/2020] [Indexed: 01/07/2023]
Abstract
Theory on the evolution of niche width argues that resource heterogeneity selects for niche breadth. For parasites, this theory predicts that parasite populations will evolve, or maintain, broader host ranges when selected in genetically diverse host populations relative to homogeneous host populations. To test this prediction, we selected the bacterial parasite Serratia marcescens to kill Caenorhabditis elegans in populations that were genetically heterogeneous (50% mix of two experimental genotypes) or homogeneous (100% of either genotype). After 20 rounds of selection, we compared the host range of selected parasites by measuring parasite fitness (i.e. virulence, the selected fitness trait) on the two focal host genotypes and on a novel host genotype. As predicted, heterogeneous host populations selected for parasites with a broader host range: these parasite populations gained or maintained virulence on all host genotypes. This result contrasted with selection in homogeneous populations of one host genotype. Here, host range contracted, with parasite populations gaining virulence on the focal host genotype and losing virulence on the novel host genotype. This pattern was not, however, repeated with selection in homogeneous populations of the second host genotype: these parasite populations did not gain virulence on the focal host genotype, nor did they lose virulence on the novel host genotype. Our results indicate that host heterogeneity can maintain broader host ranges in parasite populations. Individual host genotypes, however, vary in the degree to which they select for specialization in parasite populations.
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Affiliation(s)
- Amanda K Gibson
- Department of Biology, Emory University, Atlanta, GA 30322
- Department of Biology, University of Virginia, Virginia 22902, USA
| | | | | | - Julie Lin
- Department of Biology, Emory University, Atlanta, GA 30322
| | - Raythe Owens
- Department of Biology, Emory University, Atlanta, GA 30322
| | - Arooj Khalid
- Department of Biology, Emory University, Atlanta, GA 30322
| | - Levi T. Morran
- Department of Biology, Emory University, Atlanta, GA 30322
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48
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Feeding performance on a novel host: no adaptation over generations and differential patterns in two flea species. Parasitology 2020; 147:721-728. [DOI: 10.1017/s0031182020000244] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
AbstractTo model the colonization of a novel host by fleas, Synosternus cleopatrae and Xenopsylla ramesis, we established experimental lines maintained for 15 generations on a principal or a novel host (either co-occurring with a flea or not). We compared the blood meal size and the energy expended for digestion by fleas from the 15th generation of each line on these hosts between hosts within a line and between lines within a host asking (a) whether fleas adapt to a novel host (increased blood consumption/decreased energy expended for digestion); (b) if yes, whether this adaptation leads to the loss of ability to exploit an original host, and (c) whether the success of adaptation to a novel host depends on its ecological co-occurrence with a flea. The blood consumption and digestion energetics of fleas fed on the principal host differed from those on other hosts. The effect of the principal host on feeding performance differed between fleas, with S. cleopatrae consuming less blood and expending more energy for digestion on the principal than on any other host, whereas the opposite was true for X. ramesis. No changes in feeding performance on a novel host over generations were found. We propose several explanations for the lack of adaptation to a novel host over time. We explain the poor performance of S. cleopatrae on its principal host via its immune response mounting pattern. We argue that the principal host of a parasite is not necessarily the host on which the parasite demonstrates the best performance.
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49
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Remnant EJ, Mather N, Gillard TL, Yagound B, Beekman M. Direct transmission by injection affects competition among RNA viruses in honeybees. Proc Biol Sci 2020; 286:20182452. [PMID: 30963951 DOI: 10.1098/rspb.2018.2452] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The arrival of the ectoparasitic mite Varroa destructor on the western honeybee Apis mellifera saw a change in the diversity and prevalence of honeybee RNA viruses. One virus in particular, deformed wing virus (DWV) has become closely associated with V. destructor, leading many to conclude that V. destructor has affected viral virulence by changing the mode of transmission. While DWV is normally transmitted via feeding and faeces, V. destructor transmits viruses by direct injection. This change could have resulted in higher viral prevalence causing increased damage to the bees. Here we test the effect of a change in the mode of transmission on the composition and levels of honeybee RNA viruses in the absence of V. destructor. We find a rapid increase in levels of two viruses, sacbrood virus (SBV) and black queen cell virus (BQCV) after direct injection of viral extracts into honeybee pupae. In pupae injected with high levels of DWV extracted from symptomatic adult bees, DWV levels rapidly decline in the presence of SBV and BQCV. Further, we observe high mortality in honeybee pupae when injected with SBV and BQCV, whereas injecting pupae with high levels of DWV results in near 100% survival. Our results suggest a different explanation for the observed association between V. destructor and DWV. Instead of V. destructor causing an increase in DWV virulence, we hypothesize that direct virus inoculation, such as that mediated by a vector, quickly eliminates the most virulent honeybee viruses resulting in an association with less virulent viruses such as DWV.
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Affiliation(s)
- Emily J Remnant
- Behaviour and Genetics of Social Insects Laboratory, School of Life and Environmental Sciences, The University of Sydney , Sydney, New South Wales , Australia
| | - Niklas Mather
- Behaviour and Genetics of Social Insects Laboratory, School of Life and Environmental Sciences, The University of Sydney , Sydney, New South Wales , Australia
| | - Thomas L Gillard
- Behaviour and Genetics of Social Insects Laboratory, School of Life and Environmental Sciences, The University of Sydney , Sydney, New South Wales , Australia
| | - Boris Yagound
- Behaviour and Genetics of Social Insects Laboratory, School of Life and Environmental Sciences, The University of Sydney , Sydney, New South Wales , Australia
| | - Madeleine Beekman
- Behaviour and Genetics of Social Insects Laboratory, School of Life and Environmental Sciences, The University of Sydney , Sydney, New South Wales , Australia
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50
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Successive passaging of a plant-associated microbiome reveals robust habitat and host genotype-dependent selection. Proc Natl Acad Sci U S A 2019; 117:1148-1159. [PMID: 31806755 DOI: 10.1073/pnas.1908600116] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There is increasing interest in the plant microbiome as it relates to both plant health and agricultural sustainability. One key unanswered question is whether we can select for a plant microbiome that is robust after colonization of target hosts. We used a successive passaging experiment to address this question by selecting upon the tomato phyllosphere microbiome. Beginning with a diverse microbial community generated from field-grown tomato plants, we inoculated replicate plants across 5 plant genotypes for 4 45-d passages, sequencing the microbial community at each passage. We observed consistent shifts in both the bacterial (16S amplicon sequencing) and fungal (internal transcribed spacer region amplicon sequencing) communities across replicate lines over time, as well as a general loss of diversity over the course of the experiment, suggesting that much of the naturally observed microbial community in the phyllosphere is likely transient or poorly adapted within the experimental setting. We found that both host genotype and environment shape microbial composition, but the relative importance of genotype declines through time. Furthermore, using a community coalescence experiment, we found that the bacterial community from the end of the experiment was robust to invasion by the starting bacterial community. These results highlight that selecting for a stable microbiome that is well adapted to a particular host environment is indeed possible, emphasizing the great potential of this approach in agriculture and beyond. In light of the consistent response of the microbiome to selection in the absence of reciprocal host evolution (coevolution) described here, future studies should address how such adaptation influences host health.
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