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Li XM, Wang XY, Wei YJ, Jiang J, Cai Y, Zhang XX, Yang X, Cao H. Meta-analysis of the global prevalence and risk factors of Enterocytozoon bieneusi infection in pigs from 1999 to 2021. Prev Vet Med 2024; 225:106159. [PMID: 38422983 DOI: 10.1016/j.prevetmed.2024.106159] [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: 04/16/2023] [Revised: 01/21/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024]
Abstract
Enterocytozoon bieneusi (E. bieneusi), which is one of the most common microsporidia, has been identified as an important obligate intracellular pathogen that commonly colonizes in a variety of animal species and humans worldwide, including humans. In this study, the statistical analyses of E. bieneusi infection and prevalence were performed to clarify the relationship between different genotypes in different countries. The databases Chinese National Knowledge Infrastructure (CNKI), VIP Chinese Journal Database, Wanfang Data, PubMed, Web of Science and ScienceDirect were used for data collection. The research data were subjected to subgroup, univariate regression, and correlation, to reveal factors related to the high prevalence of E. bieneusi. A total of, 34 of the 498 articles published before April 2022 met the inclusion criteria. The global prevalence of E. bieneusi in pigs was 37.69% (5175/12672). The prevalence of E. bieneusi in nursery pigs was 58.87% (588/946). In developing countries and Asia, the highest prevalence of E. bieneusi in pigs were 37.62% (4752/11645) and 40.14% (4715/11345), respectively. Moreover, humans and pigs have been found to be infected with the same genotype of E. bieneusi in some cases, as evidenced by the consolidation of genotype information. The results showed that pigs are susceptible to E. bieneusi during the nursery period. The prevalence of E. bieneusi is high in developing countries, and its genotype prevalence varies in each country. Thus, it is essential to strengthen the health inspection of vulnerable groups and customs quarantine inspection.
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Affiliation(s)
- Xiao-Man Li
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, China
| | - Xiang-Yu Wang
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, China
| | - Yong-Jie Wei
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, China
| | - Jing Jiang
- College of Life Sciences, Changchun Sci-Tech University, Shuangyang, Jilin Province 130600, China.
| | - Yanan Cai
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, Jilin Province 130118, China
| | - Xiao-Xuan Zhang
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong Province 266109, China
| | - Xing Yang
- Department of Medical Microbiology and Immunology, School of Basic Medicine, Dali, Yunnan Province 671000, China.
| | - Hongwei Cao
- School of Pharmacy, Yancheng Teachers University, Yancheng, Jiangsu Province 224002, China.
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Bypassing Mendel's First Law: Transmission Ratio Distortion in Mammals. Int J Mol Sci 2023; 24:ijms24021600. [PMID: 36675116 PMCID: PMC9863905 DOI: 10.3390/ijms24021600] [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: 11/29/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Mendel's law of segregation states that the two alleles at a diploid locus should be transmitted equally to the progeny. A genetic segregation distortion, also referred to as transmission ratio distortion (TRD), is a statistically significant deviation from this rule. TRD has been observed in several mammal species and may be due to different biological mechanisms occurring at diverse time points ranging from gamete formation to lethality at post-natal stages. In this review, we describe examples of TRD and their possible mechanisms in mammals based on current knowledge. We first focus on the differences between TRD in male and female gametogenesis in the house mouse, in which some of the most well studied TRD systems have been characterized. We then describe known TRD in other mammals, with a special focus on the farmed species and in the peculiar common shrew species. Finally, we discuss TRD in human diseases. Thus far, to our knowledge, this is the first time that such description is proposed. This review will help better comprehend the processes involved in TRD. A better understanding of these molecular mechanisms will imply a better comprehension of their impact on fertility and on genome evolution. In turn, this should allow for better genetic counseling and lead to better care for human families.
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Qin Y, Chen C, Qin YF, Yang XB, Li MH, Meng XZ, Zhao ZY, Ma N, Cai Y, Zhang Y, Zhao Q. Prevalence and related factors of Enterocytozoon bieneusi in cattle: A global systematic review and meta-analysis. Prev Vet Med 2022; 208:105775. [DOI: 10.1016/j.prevetmed.2022.105775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 09/25/2022] [Accepted: 10/04/2022] [Indexed: 10/31/2022]
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Kloock A, Peters L, Rafaluk-Mohr C. Sex Matters: Effects of Sex and Mating in the Presence and Absence of a Protective Microbe. Front Cell Infect Microbiol 2021; 11:713387. [PMID: 34692559 PMCID: PMC8529166 DOI: 10.3389/fcimb.2021.713387] [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: 05/22/2021] [Accepted: 09/10/2021] [Indexed: 11/13/2022] Open
Abstract
In most animals, female investment in offspring production is greater than for males. Lifetime reproductive success (LRS) is predicted to be optimized in females through extended lifespans to maximize reproductive events by increased investment in immunity. Males, however, maximize lifetime reproductive success by obtaining as many matings as possible. In populations consisting of mainly hermaphrodites, optimization of reproductive success may be primarily influenced by gamete and resource availability. Microbe-mediated protection (MMP) is known to affect both immunity and reproduction, but whether sex influences the response to MMP remains to be explored. Here, we investigated the sex-specific differences in survival, behavior, and timing of offspring production between feminized hermaphrodite (female) and male Caenorhabditis elegans following pathogenic infection with Staphylococcus aureus with or without MMP by Enterococcus faecalis. Overall, female survival decreased with increased mating. With MMP, females increased investment into offspring production, while males displayed higher behavioral activity. MMP was furthermore able to dampen costs that females experience due to mating with males. These results demonstrate that strategies employed under pathogen infection with and without MMP are sex dependent.
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Affiliation(s)
- Anke Kloock
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Lena Peters
- Department of Zoology, University of Oxford, Oxford, United Kingdom
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Gowler CD, Rogalski MA, Shaw CL, Hunsberger KK, Duffy MA. Density, parasitism, and sexual reproduction are strongly correlated in lake Daphnia populations. Ecol Evol 2021; 11:10446-10456. [PMID: 34367587 PMCID: PMC8328469 DOI: 10.1002/ece3.7847] [Citation(s) in RCA: 3] [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: 03/23/2021] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 01/06/2023] Open
Abstract
Many organisms can reproduce both asexually and sexually. For cyclical parthenogens, periods of asexual reproduction are punctuated by bouts of sexual reproduction, and the shift from asexual to sexual reproduction has large impacts on fitness and population dynamics. We studied populations of Daphnia dentifera to determine the amount of investment in sexual reproduction as well as the factors associated with variation in investment in sex. To do so, we tracked host density, infections by nine different parasites, and sexual reproduction in 15 lake populations of D. dentifera for 3 years. Sexual reproduction was seasonal, with male and ephippial female production beginning as early as late September and generally increasing through November. However, there was substantial variation in the prevalence of sexual individuals across populations, with some populations remaining entirely asexual throughout the study period and others shifting almost entirely to sexual females and males. We found strong relationships between density, prevalence of infection, parasite species richness, and sexual reproduction in these populations. However, strong collinearity between density, parasitism, and sexual reproduction means that further work will be required to disentangle the causal mechanisms underlying these relationships.
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Affiliation(s)
- Camden D. Gowler
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMIUSA
| | - Mary A. Rogalski
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMIUSA
- Biology and Environmental StudiesBowdoin CollegeBrunswickMEUSA
| | - Clara L. Shaw
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMIUSA
- Department of BiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
| | | | - Meghan A. Duffy
- Department of Ecology & Evolutionary BiologyUniversity of MichiganAnn ArborMIUSA
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Cabalzar AP, Fields PD, Kato Y, Watanabe H, Ebert D. Parasite-mediated selection in a natural metapopulation of Daphnia magna. Mol Ecol 2019; 28:4770-4785. [PMID: 31591747 DOI: 10.1111/mec.15260] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 01/03/2023]
Abstract
Parasite-mediated selection varying across time and space in metapopulations is expected to result in host local adaptation and the maintenance of genetic diversity in disease-related traits. However, nonadaptive processes like migration and extinction-(re)colonization dynamics might interfere with adaptive evolution. Understanding how adaptive and nonadaptive processes interact to shape genetic variability in life-history and disease-related traits can provide important insights into their evolution in subdivided populations. Here we investigate signatures of spatially fluctuating, parasite-mediated selection in a natural metapopulation of Daphnia magna. Host genotypes from infected and uninfected populations were genotyped at microsatellite markers, and phenotyped for life-history and disease traits in common garden experiments. Combining phenotypic and genotypic data a QST -FST -like analysis was conducted to test for signatures of parasite mediated selection. We observed high variation within and among populations for phenotypic traits, but neither an indication of host local adaptation nor a cost of resistance. Infected populations have a higher gene diversity (Hs) than uninfected populations and Hs is strongly positively correlated with fitness. These results suggest a strong parasite effect on reducing population level inbreeding. We discuss how stochastic processes related to frequent extinction-(re)colonization dynamics as well as host and parasite migration impede the evolution of resistance in the infected populations. We suggest that the genetic and phenotypic patterns of variation are a product of dynamic changes in the host gene pool caused by the interaction of colonization bottlenecks, inbreeding, immigration, hybrid vigor, rare host genotype advantage and parasitism. Our study highlights the effect of the parasite in ameliorating the negative fitness consequences caused by the high drift load in this metapopulation.
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Affiliation(s)
- Andrea P Cabalzar
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Yasuhiko Kato
- Department of Biotechnology, Division of Advance Science and Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Hajime Watanabe
- Department of Biotechnology, Division of Advance Science and Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,Tvärminne Zoological Station, Tvärminne, Finland
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Wijayawardene NN, Pawłowska J, Letcher PM, Kirk PM, Humber RA, Schüßler A, Wrzosek M, Muszewska A, Okrasińska A, Istel Ł, Gęsiorska A, Mungai P, Lateef AA, Rajeshkumar KC, Singh RV, Radek R, Walther G, Wagner L, Walker C, Wijesundara DSA, Papizadeh M, Dolatabadi S, Shenoy BD, Tokarev YS, Lumyong S, Hyde KD. Notes for genera: basal clades of Fungi (including Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota). FUNGAL DIVERS 2018. [DOI: 10.1007/s13225-018-0409-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Ringot G, Gasparini J, Wagner M, Cheikh Albassatneh M, Frantz A. More and smaller resting eggs along a gradient for pollution by metals: dispersal, dormancy and detoxification strategies in Daphnia? Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Gabrielle Ringot
- Sorbonne Universités, Université Paris Diderot, Université Paris-Est Créteil, CNRS, INRA, IRD, Institute of Ecology and Environmental Science – Paris (iEES-Paris), Campus Pierre et Marie Curie, 4 place Jussieu, Paris, France
| | - Julien Gasparini
- Sorbonne Universités, Université Paris Diderot, Université Paris-Est Créteil, CNRS, INRA, IRD, Institute of Ecology and Environmental Science – Paris (iEES-Paris), Campus Pierre et Marie Curie, 4 place Jussieu, Paris, France
| | - Marie Wagner
- Sorbonne Universités, Université Paris Diderot, Université Paris-Est Créteil, CNRS, INRA, IRD, Institute of Ecology and Environmental Science – Paris (iEES-Paris), Campus Pierre et Marie Curie, 4 place Jussieu, Paris, France
| | - Marwan Cheikh Albassatneh
- Sorbonne Universités, Université Paris Diderot, Université Paris-Est Créteil, CNRS, INRA, IRD, Institute of Ecology and Environmental Science – Paris (iEES-Paris), Campus Pierre et Marie Curie, 4 place Jussieu, Paris, France
| | - Adrien Frantz
- Sorbonne Universités, Université Paris Diderot, Université Paris-Est Créteil, CNRS, INRA, IRD, Institute of Ecology and Environmental Science – Paris (iEES-Paris), Campus Pierre et Marie Curie, 4 place Jussieu, Paris, France
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9
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Roulin AC, Mariadassou M, Hall MD, Walser JC, Haag C, Ebert D. High genetic variation in resting-stage production in a metapopulation: Is there evidence for local adaptation? Evolution 2015; 69:2747-56. [DOI: 10.1111/evo.12770] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/20/2015] [Accepted: 08/20/2015] [Indexed: 12/23/2022]
Affiliation(s)
- Anne C. Roulin
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- Institute of Plant Biology; University of Zurich; Zollikerstrasse 107 8008 Zurich Switzerland
| | | | - Matthew D. Hall
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- School of Biological Sciences; Monash University; Melbourne 3800 Australia
| | - Jean-Claude Walser
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- Genetic Diversity Centre; Universitätstrasse 16, CHN E 55 8092 Zürich Switzerland
| | - Christoph Haag
- CNRS-UMR5175 CEFE; 1919, Route de Mende 34293 Montpellier France
| | - Dieter Ebert
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- Tvärminne Zoological Station; Helsinki University; Hanko Finland
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10
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Corradi N. Microsporidia: Eukaryotic Intracellular Parasites Shaped by Gene Loss and Horizontal Gene Transfers. Annu Rev Microbiol 2015. [PMID: 26195306 DOI: 10.1146/annurev-micro-091014-104136] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microsporidia are eukaryotic parasites of many animals that appear to have adapted to an obligate intracellular lifestyle by modifying the morphology and content of their cells. Living inside other cells, they have lost many, or all, metabolic functions, resulting in genomes that are always gene poor and often very small. The minute content of microsporidian genomes led many to assume that these parasites are biochemically static and uninteresting. However, recent studies have demonstrated that these organisms can be surprisingly complex and dynamic. In this review I detail the most significant recent advances in microsporidian genomics and discuss how these have affected our understanding of many biological aspects of these peculiar eukaryotic intracellular pathogens.
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Affiliation(s)
- Nicolas Corradi
- Canadian Institute for Advanced Research, Department of Biology, University of Ottawa, Ontario, Canada K1N 6N5;
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11
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Routtu J, Ebert D. Genetic architecture of resistance in Daphnia hosts against two species of host-specific parasites. Heredity (Edinb) 2014; 114:241-8. [PMID: 25335558 DOI: 10.1038/hdy.2014.97] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 08/21/2014] [Accepted: 08/27/2014] [Indexed: 02/04/2023] Open
Abstract
Understanding the genetic architecture of host resistance is key for understanding the evolution of host-parasite interactions. Evolutionary models often assume simple genetics based on few loci and strong epistasis. It is unknown, however, whether these assumptions apply to natural populations. Using a quantitative trait loci (QTL) approach, we explore the genetic architecture of resistance in the crustacean Daphnia magna to two of its natural parasites: the horizontally transmitted bacterium Pasteuria ramosa and the horizontally and vertically transmitted microsporidium Hamiltosporidium tvaerminnensis. These two systems have become models for studies on the evolution of host-parasite interactions. In the QTL panel used here, Daphnia's resistance to P. ramosa is controlled by a single major QTL (which explains 50% of the observed variation). Resistance to H. tvaerminnensis horizontal infections shows a signature of a quantitative trait based in multiple loci with weak epistatic interactions (together explaining 38% variation). Resistance to H. tvaerminnensis vertical infections, however, shows only one QTL (explaining 13.5% variance) that colocalizes with one of the QTLs for horizontal infections. QTLs for resistance to Pasteuria and Hamiltosporidium do not colocalize. We conclude that the genetics of resistance in D. magna are drastically different for these two parasites. Furthermore, we infer that based on these and earlier results, the mechanisms of coevolution differ strongly for the two host-parasite systems. Only the Pasteuria-Daphnia system is expected to follow the negative frequency-dependent selection (Red Queen) model. How coevolution works in the Hamiltosporidium-Daphnia system remains unclear.
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Affiliation(s)
- J Routtu
- Zoologisches Institut, Universität Basel, Basel, Switzerland
| | - D Ebert
- Zoologisches Institut, Universität Basel, Basel, Switzerland
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12
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Roulin AC, Routtu J, Hall MD, Janicke T, Colson I, Haag CR, Ebert D. Local adaptation of sex induction in a facultative sexual crustacean: insights from QTL mapping and natural populations of Daphnia magna. Mol Ecol 2013; 22:3567-79. [PMID: 23786714 DOI: 10.1111/mec.12308] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/12/2013] [Accepted: 02/17/2013] [Indexed: 02/02/2023]
Abstract
Dormancy is a common adaptation in invertebrates to survive harsh conditions. Triggered by environmental cues, populations produce resting eggs that allow them to survive temporally unsuitable conditions. Daphnia magna is a crustacean that reproduces by cyclical parthenogenesis, alternating between the production of asexual offspring and the sexual reproduction of diapausing eggs (ephippia). Prior to ephippia production, males (necessary to ensure ephippia fertilization) are produced parthenogenetically. Both the production of ephippia and the parthenogenetic production of males are induced by environmental factors. Here, we test the hypothesis that the induction of D. magna resting egg production shows a signature of local adaptation. We postulated that Daphnia from permanent ponds would produce fewer ephippia and males than Daphnia from intermittent ponds and that the frequency and season of habitat deterioration would correlate with the timing and amount of male and ephippia production. To test this, we quantified the production of males and ephippia in clonal D. magna populations in several different controlled environments. We found that the production of both ephippia and males varies strongly among populations in a way that suggests local adaptation. By performing quantitative trait locus mapping with parent clones from contrasting pond environments, we identified nonoverlapping genomic regions associated with male and ephippia production. As the traits are influenced by two different genomic regions, and both are necessary for successful resting egg production, we suggest that the genes for their induction co-evolve.
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Affiliation(s)
- Anne C Roulin
- Department of Evolutionary Biology, Zoological Institute, University of Basel, Vesalgasse 1, Basel, Switzerland.
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13
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Duneau D, Luijckx P, Ruder LF, Ebert D. Sex-specific effects of a parasite evolving in a female-biased host population. BMC Biol 2012; 10:104. [PMID: 23249484 PMCID: PMC3568004 DOI: 10.1186/1741-7007-10-104] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 12/18/2012] [Indexed: 11/28/2022] Open
Abstract
Background Males and females differ in many ways and might present different opportunities and challenges to their parasites. In the same way that parasites adapt to the most common host type, they may adapt to the characteristics of the host sex they encounter most often. To explore this hypothesis, we characterized host sex-specific effects of the parasite Pasteuria ramosa, a bacterium evolving in naturally, strongly, female-biased populations of its host Daphnia magna. Results We show that the parasite proliferates more successfully in female hosts than in male hosts, even though males and females are genetically identical. In addition, when exposure occurred when hosts expressed a sexual dimorphism, females were more infected. In both host sexes, the parasite causes a similar reduction in longevity and leads to some level of castration. However, only in females does parasite-induced castration result in the gigantism that increases the carrying capacity for the proliferating parasite. Conclusions We show that mature male and female Daphnia represent different environments and reveal one parasite-induced symptom (host castration), which leads to increased carrying capacity for parasite proliferation in female but not male hosts. We propose that parasite induced host castration is a property of parasites that evolved as an adaptation to specifically exploit female hosts.
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Affiliation(s)
- David Duneau
- University of Basel, Zoological Institute, Vesalgasse 1, 4051 Basel, Switzerland.
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14
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Lass S, Hottinger JW, Fabbro T, Ebert D. Converging seasonal prevalence dynamics in experimental epidemics. BMC Ecol 2011; 11:14. [PMID: 21586126 PMCID: PMC3112375 DOI: 10.1186/1472-6785-11-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 05/17/2011] [Indexed: 11/14/2022] Open
Abstract
Background Regular seasonal changes in prevalence of infectious diseases are often observed in nature, but the mechanisms are rarely understood. Empirical tests aiming at a better understanding of seasonal prevalence patterns are not feasible for most diseases and thus are widely lacking. Here, we set out to study experimentally the seasonal prevalence in an aquatic host-parasite system. The microsporidian parasite Hamiltosporidium tvärminnensis exhibits pronounced seasonality in natural rock pool populations of its host, Daphnia magna with a regular increase of prevalence during summer and a decrease during winter. An earlier study was, however, unable to test if different starting conditions (initial prevalence) influence the dynamics of the disease in the long term. Here, we aim at testing how the starting prevalence affects the regular prevalence changes over a 4-year period in experimental populations. Results In an outdoor experiment, populations were set up to include the extremes of the prevalence spectrum observed in natural populations: 5% initial prevalence mimicking a newly invading parasite, 100% mimicking a rock pool population founded by infected hosts only, and 50% prevalence which is commonly observed in natural populations in spring. The parasite exhibited similar prevalence changes in all treatments, but seasonal patterns in the 100% treatment differed significantly from those in the 5% and 50% treatments. Populations started with 5% and 50% prevalence exhibited strong and regular seasonality already in the first year. In contrast, the amplitude of changes in the 100% treatment was low throughout the experiment demonstrating the long-lasting effect of initial conditions on prevalence dynamics. Conclusions Our study shows that the time needed to approach the seasonal changes in prevalence depends strongly on the initial prevalence. Because individual D. magna populations in this rock pool metapopulation are mostly short lived, only few populations might ever reach a point where the initial conditions are not visible anymore.
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Affiliation(s)
- Sandra Lass
- Départment de Biology, Ecologie et Evolution, Université de Fribourg, Chemin du Musée 10, Fribourg, 1700, Switzerland.
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15
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ROTH O, SCHARSACK JP, KELLER I, REUSCH TBH. Bateman’s principle and immunity in a sex-role reversed pipefish. J Evol Biol 2011; 24:1410-20. [DOI: 10.1111/j.1420-9101.2011.02273.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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16
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Corradi N, Slamovits CH. The intriguing nature of microsporidian genomes. Brief Funct Genomics 2010; 10:115-24. [PMID: 21177329 DOI: 10.1093/bfgp/elq032] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Microsporidia are a group of highly adapted unicellular fungi that are known to infect a wide range of animals, including humans and species of great economic importance. These organisms are best known for their very simple cellular and genomic features, an adaptive consequence of their obligate intracellular parasitism. In the last decade, the acquisition of a large amount of genomic and transcriptomic data from several microsporidian species has greatly improved our understanding of the consequences of a purely intracellular lifestyle. In particular, genome sequence data from these pathogens has revealed how obligate intracellular parasitism can result in radical changes in the composition and structure of nuclear genomes and how these changes can affect cellular and evolutionary mechanisms that are otherwise well conserved among eukaryotes. This article reviews our current understanding of the genome content and structure of microsporidia, discussing their evolutionary origin and cataloguing the mechanisms that have often been involved in their extreme reduction.
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Affiliation(s)
- Nicolas Corradi
- Canadian Institute for Advanced Research, Department of Biology, University of Ottawa, Gendron Hall, ON, Canada.
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17
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Bieger A, Ebert D. Expression of parasite virulence at different host population densities under natural conditions. Oecologia 2009; 160:247-55. [PMID: 19219457 DOI: 10.1007/s00442-009-1297-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Accepted: 01/08/2009] [Indexed: 10/21/2022]
Abstract
It has recently been suggested that the expression of parasite virulence depends on host population density, such that infected hosts have a higher sensitivity to density, and thus reach their carrying capacity earlier than uninfected hosts. In this scenario, parasite-induced reduction in fitness (i.e., virulence) increases with host density. We tested this hypothesis experimentally, using outdoor mesocosm populations of Daphnia magna infected by the microsporidian Octosporea bayeri. Contrary to the prediction, virulence was independent of host density. In a competition experiment with initial prevalence of 50%, O. bayeri reduced the competitive ability of infected Daphnia within the asexual growth phase independent of initial host population density. In an additional experiment we set up populations with 100% and 0% prevalence and followed their population dynamics over the whole season. Consistent with the competition experiment, we found no difference in population dynamics within the asexual growth phase of the host, suggesting that infected hosts are not more sensitive to density than uninfected hosts. The additional experiment, however, included more than the initial growth phase as did the competition experiment. Eventually, after 100 days, 100% infected populations assumed a reduced carrying capacity compared to uninfected populations. We identify and discuss three reasons for the discrepancy between our experiment and the predictions.
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Affiliation(s)
- Annette Bieger
- Zoologisches Institut, Universität Basel, Vesalgasse 1, 4051 Basel, Switzerland.
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ROTH O, KURTZ J. The stimulation of immune defence accelerates development in the red flour beetle (Tribolium castaneum). J Evol Biol 2008; 21:1703-10. [DOI: 10.1111/j.1420-9101.2008.01584.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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