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Dini FM, Caffara M, Magri A, Cantori A, Luci V, Monno A, Galuppi R. Sentinels in the shadows: Exploring Toxoplasma gondii and other Sarcocystidae parasites in synanthropic rodents and their public health implications. Int J Parasitol Parasites Wildl 2024; 24:100939. [PMID: 38655448 PMCID: PMC11035367 DOI: 10.1016/j.ijppaw.2024.100939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/16/2024] [Accepted: 04/16/2024] [Indexed: 04/26/2024]
Abstract
Synanthropic rodents play a crucial role in maintaining the life cycle of Toxoplasma gondii in anthropized regions and can serve as indicators of environmental oocyst contamination. This investigation aimed to explore the occurrence of T. gondii infection within synanthropic rodent populations using a molecular diagnostic technique targeting the 18S rDNA gene, which is generic for Coccidia, with subsequent specific PCR confirmation. We examined 97 brown rats (Rattus norvegicus), 67 black rats (R. rattus), 47 house mice (Mus musculus), and 1 common shrew (Sorex araneus). PCR tests were conducted on the brain, heart, and tongue tissues. PCR tested positive in at least one of the examined tissues in 26 R. norvegicus (26.8%), 13 R. rattus (19.4%), and 13 M. musculus (27.6%). Sequencing comparisons by BLAST allowed us to identify four different species of cyst-forming Apicomplexa. In particular, T. gondii DNA was detected in 13 (6.1%) rodents, Hammondia hammondi (including H. hammondi-like organisms) in 36 (17%) subjects, Besnoitia sp. (in two cases identified as B. besnoiti) in 8 (3.7%), and Sarcocystis gigantea in two (0.94%). Rodents from peri-urban and urban environments can act as indicators of environmental contamination by oocysts of apicomplexan parasites with cats as definitive hosts, such as T. gondii, H. hammondi, and S. gigantea, the latter of which has never been previously recorded in rodents. Moreover, the presence of B. besnoiti, a parasite with an unidentified definitive host in Europe, sheds light on the potential role of these hosts as infection sentinels.
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Affiliation(s)
- Filippo Maria Dini
- Department of Veterinary Medical Sciences (DIMEVET), Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Monica Caffara
- Department of Veterinary Medical Sciences (DIMEVET), Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Alice Magri
- Department of Veterinary Medical Sciences (DIMEVET), Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Alessia Cantori
- Department of Veterinary Medical Sciences (DIMEVET), Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Valentina Luci
- Department of Veterinary Medical Sciences (DIMEVET), Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Antonio Monno
- Department of Veterinary Medical Sciences (DIMEVET), Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Roberta Galuppi
- Department of Veterinary Medical Sciences (DIMEVET), Alma Mater Studiorum University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
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Rezende-Gondim MM, da Silva AV, Dubey JP, Schares GRM, Gondim LFP. Immunomagnetic separation of Toxoplasma gondii and Hammondia spp. tissue cysts generated in cell culture. Front Vet Sci 2022; 9:1033380. [PMID: 36311681 PMCID: PMC9606798 DOI: 10.3389/fvets.2022.1033380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 09/22/2022] [Indexed: 11/04/2022] Open
Abstract
Toxoplasma gondii is commonly transmitted among animals and humans by ingestion of infected animal tissues or by consumption of food and water contaminated with environmentally-resistant oocysts excreted by cats. Tissue cysts and oocysts have different walls, whose structures and compositions are poorly known. Herein, we describe an immunomagnetic separation (IMS) method that was successfully used for purification of T. gondii tissue cysts generated in cell culture. We used an IgG monoclonal antibody (mAb) that reacts against antigens in tissue cyst walls. Many in vitro produced cysts were obtained by this IMS; >2,000 T. gondii cysts were isolated from a single culture flask of 25 cm2. Tissue cysts from two Hammondia spp., H. hammondi, and H. heydorni, produced in cell culture were also separated using this method. As a reference, purification of tissue cysts by Percoll gradients was used. Percoll was able to separate T. gondii tissue cysts produced in mice but was not suitable for purifying T. gondii tissue cysts produced in vitro. The IMS described here should favor proteomic studies involving tissue cysts of T. gondii.
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Affiliation(s)
- Mariana M. Rezende-Gondim
- Departamento de Anatomia, Patologia e Clínicas, Escola de Medicina Veterinária e Zootecnia, Universidade Federal da Bahia, Salvador, Bahia, Brazil
| | - Aristeu V. da Silva
- Departamento de Biologia, Universidade Estadual de Feira de Santana, Feira de Santana, Bahia, Brazil
| | - Jitender P. Dubey
- United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal Parasitic Diseases Laboratory, Beltsville, MD, United States
| | - Gereon R. M. Schares
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, National Reference Centre for Toxoplasmosis, Greifswald-Insel Riems, Germany
| | - Luís F. P. Gondim
- Departamento de Anatomia, Patologia e Clínicas, Escola de Medicina Veterinária e Zootecnia, Universidade Federal da Bahia, Salvador, Bahia, Brazil,*Correspondence: Luís F. P. Gondim
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Schares G, Globokar Vrhovec M, Tuschy M, Joeres M, Bärwald A, Koudela B, Dubey JP, Maksimov P, Conraths FJ. A real-time quantitative polymerase chain reaction for the specific detection of Hammondia hammondi and its differentiation from Toxoplasma gondii. Parasit Vectors 2021; 14:78. [PMID: 33494796 PMCID: PMC7830817 DOI: 10.1186/s13071-020-04571-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 12/28/2020] [Indexed: 12/19/2022] Open
Abstract
Introduction Hammondia hammondi and Toxoplasma gondii are closely related protozoan parasites, but only T. gondii is zoonotic. Both species use felids as definitive hosts and cannot be differentiated by oocyst morphology. In T. gondii, a 529-base pair (bp) repetitive element (TgREP-529) is of utmost diagnostic importance for polymerase chain reaction (PCR) diagnostic tests. We identified a similar repetitive region in the H. hammondi genome (HhamREP-529). Methods Based on reported sequences, primers and probes were selected in silico and optimal primer probe combinations were explored, also by including previously published primers. The analytical sensitivity was tested using serial dilutions of oocyst DNA. For testing analytical specificity, DNA isolated from several related species was used as controls. The newly established TaqMan PCR (Hham-qPCR1) was applied to tissues collected from H. hammondi-infected gamma-interferon gene knockout (GKO) mice at varying time points post-infection. Results Ten forward and six reverse primers were tested in varying combinations. Four potentially suitable dual-labelled probes were selected. One set based on the primer pair (Hham275F, Hham81R) and the probe (Hham222P) yielded optimal results. In addition to excellent analytic specificity, the assay revealed an analytical sensitivity of genome equivalents of less than one oocyst. Investigation of the tissue distribution in GKO mice revealed the presence of parasite DNA in all examined organs, but to a varying extent, suggesting 100- to 10,000-fold differences in parasitic loads between tissues in the chronic state of infection, 42 days post-infection. Discussion The use of the 529-bp repeat of H. hammondi is suitable for establishing a quantitative real-time PCR assay, because this repeat probably exists about 200 times in the genome of a single organism, like its counterpart in T. gondii. Although there were enough sequence data available, only a few of the primers predicted in silico revealed sufficient amplification; the identification of a suitable probe was also difficult. This is in accord with our previous observations on considerable variability in the 529-bp repetitive element of H. hammondi. Conclusions The H. hammondi real-time PCR represents an important novel diagnostic tool for epidemiological and cell biological studies on H. hammondi and related parasites. ![]()
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Affiliation(s)
- Gereon Schares
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | | | - Mareen Tuschy
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Maike Joeres
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Andrea Bärwald
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Bretislav Koudela
- Central European Institute of Technology (CEITEC), University of Veterinary and Pharmaceutical Sciences, Palackého tř. 1946/1, Brno, 612 42, Czech Republic.,Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Palackého tř. 1946/1, Brno, 612 42, Czech Republic
| | - Jitender P Dubey
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agriculture Research Service, United States Department of Agriculture, Building 1001, Beltsville, MD, 20705-2350, USA
| | - Pavlo Maksimov
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Franz J Conraths
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
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Sokol SL, Wong ZS, Boyle JP, Dubey JP. Generation of Toxoplasma gondii and Hammondia hammondi Oocysts and Purification of Their Sporozoites for Downstream Manipulation. Methods Mol Biol 2020; 2071:81-98. [PMID: 31758447 DOI: 10.1007/978-1-4939-9857-9_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Toxoplasma gondii tachyzoites and bradyzoites are studied extensively in the laboratory due to the ease with which they can be cultured. In contrast, oocysts and the sporozoites within them are more difficult to work with, in that cat infections are required for their generation and isolating sporozoites requires a laborious excystation procedure. More over some parasite species such as Hammondia hammondi are obligately heteroxenous and require passage through a cat for completion of the life cycle. There is no debate that there is great value in studying this important life cycle stage, and we present here a detailed description of the current protocols used in our laboratories to generate and isolate T. gondii and H. hammondi oocysts, and to excyst and purify the sporozoites within them for use in downstream experimental applications.
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Sokol-Borrelli SL, Coombs RS, Boyle JP. A Comparison of Stage Conversion in the Coccidian Apicomplexans Toxoplasma gondii, Hammondia hammondi, and Neospora caninum. Front Cell Infect Microbiol 2020; 10:608283. [PMID: 33344268 PMCID: PMC7744739 DOI: 10.3389/fcimb.2020.608283] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 11/06/2020] [Indexed: 01/31/2023] Open
Abstract
Stage conversion is a critical life cycle feature for several Apicomplexan parasites as the ability to switch between life forms is critical for replication, dissemination, pathogenesis and ultimately, transmission to a new host. In order for these developmental transitions to occur, the parasite must first sense changes in their environment, such as the presence of stressors or other environmental signals, and then respond to these signals by initiating global alterations in gene expression. As our understanding of the genetic components required for stage conversion continues to broaden, we can better understand the conserved mechanisms for this process and unique components and their contribution to pathogenesis by comparing stage conversion in multiple closely related species. In this review, we will discuss what is currently known about the mechanisms driving stage conversion in Toxoplasma gondii and its closest relatives Hammondia hammondi and Neospora caninum. Work by us and others has shown that these species have some important differences in the way that they (1) progress through their life cycle and (2) respond to stage conversion initiating stressors. To provide a specific example of species-specific complexities associated with stage conversion, we will discuss our recent published and unpublished work comparing stress responses in T. gondii and H. hammondi.
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Affiliation(s)
| | | | - Jon P. Boyle
- University of Pittsburgh, Department of Biological Sciences, Kenneth P. Dietrich School of Arts and Sciences, Pittsburgh, PA, United States
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Wong ZS, Borrelli SLS, Coyne CC, Boyle JP. Cell type- and species-specific host responses to Toxoplasma gondii and its near relatives. Int J Parasitol 2020; 50:423-431. [PMID: 32407716 PMCID: PMC8281328 DOI: 10.1016/j.ijpara.2020.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/30/2020] [Accepted: 04/03/2020] [Indexed: 10/24/2022]
Abstract
Toxoplasma gondii is remarkably unique in its ability to successfully infect vertebrate hosts from multiple phyla and can successfully infect most cells within these organisms. The infection outcome in each of these species is determined by the complex interaction between parasite and host genotype. As techniques to quantify global changes in cell function become more readily available and precise, new data are coming to light about how (i) different host cell types respond to parasitic infection and (ii) different parasite species impact the host. Here we focus on recent studies comparing the response to intracellular parasitism by different cell types and insights into understanding host-parasite interactions from comparative studies on T. gondii and its close extant relatives.
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Affiliation(s)
- Zhee S Wong
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sarah L Sokol Borrelli
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, United States
| | - Carolyn C Coyne
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Jon P Boyle
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, United States.
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Goodswen SJ, Kennedy PJ, Ellis JT. A Gene-Based Positive Selection Detection Approach to Identify Vaccine Candidates Using Toxoplasma gondii as a Test Case Protozoan Pathogen. Front Genet 2018; 9:332. [PMID: 30177953 PMCID: PMC6109633 DOI: 10.3389/fgene.2018.00332] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 08/02/2018] [Indexed: 11/22/2022] Open
Abstract
Over the last two decades, various in silico approaches have been developed and refined that attempt to identify protein and/or peptide vaccines candidates from informative signals encoded in protein sequences of a target pathogen. As to date, no signal has been identified that clearly indicates a protein will effectively contribute to a protective immune response in a host. The premise for this study is that proteins under positive selection from the immune system are more likely suitable vaccine candidates than proteins exposed to other selection pressures. Furthermore, our expectation is that protein sequence regions encoding major histocompatibility complexes (MHC) binding peptides will contain consecutive positive selection sites. Using freely available data and bioinformatic tools, we present a high-throughput approach through a pipeline that predicts positive selection sites, protein subcellular locations, and sequence locations of medium to high T-Cell MHC class I binding peptides. Positive selection sites are estimated from a sequence alignment by comparing rates of synonymous (dS) and non-synonymous (dN) substitutions among protein coding sequences of orthologous genes in a phylogeny. The main pipeline output is a list of protein vaccine candidates predicted to be naturally exposed to the immune system and containing sites under positive selection. Candidates are ranked with respect to the number of consecutive sites located on protein sequence regions encoding MHCI-binding peptides. Results are constrained by the reliability of prediction programs and quality of input data. Protein sequences from Toxoplasma gondii ME49 strain (TGME49) were used as a case study. Surface antigen (SAG), dense granules (GRA), microneme (MIC), and rhoptry (ROP) proteins are considered worthy T. gondii candidates. Given 8263 TGME49 protein sequences processed anonymously, the top 10 predicted candidates were all worthy candidates. In particular, the top ten included ROP5 and ROP18, which are T. gondii virulence determinants. The chance of randomly selecting a ROP protein was 0.2% given 8263 sequences. We conclude that the approach described is a valuable addition to other in silico approaches to identify vaccines candidates worthy of laboratory validation and could be adapted for other apicomplexan parasite species (with appropriate data).
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Affiliation(s)
- Stephen J Goodswen
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
| | - Paul J Kennedy
- School of Software, Faculty of Engineering and Information Technology, Centre for Artificial Intelligence, University of Technology Sydney, Ultimo, NSW, Australia
| | - John T Ellis
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW, Australia
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Sokol SL, Primack AS, Nair SC, Wong ZS, Tembo M, Verma SK, Cerqueira-Cezar CK, Dubey JP, Boyle JP. Dissection of the in vitro developmental program of Hammondia hammondi reveals a link between stress sensitivity and life cycle flexibility in Toxoplasma gondii. eLife 2018; 7:36491. [PMID: 29785929 PMCID: PMC5963921 DOI: 10.7554/elife.36491] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 04/18/2018] [Indexed: 12/27/2022] Open
Abstract
Most eukaryotic parasites are obligately heteroxenous, requiring sequential infection of different host species in order to survive. Toxoplasma gondii is a rare exception to this rule, having a uniquely facultative heteroxenous life cycle. To understand the origins of this phenomenon, we compared development and stress responses in T. gondii to those of its its obligately heteroxenous relative, Hammondia hammondi and have identified multiple H. hammondi growth states that are distinct from those in T. gondii. Of these, the most dramatic difference was that H. hammondi was refractory to stressors that robustly induce cyst formation in T. gondii, and this was reflected most dramatically in its unchanging transcriptome after stress exposure. We also found that H. hammondi could be propagated in vitro for up to 8 days post-excystation, and we exploited this to generate the first ever transgenic H. hammondi line. Overall our data show that H. hammondi zoites grow as stringently regulated, unique life stages that are distinct from T. gondii tachyzoites, and implicate stress sensitivity as a potential developmental innovation that increased the flexibility of the T. gondii life cycle.
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Affiliation(s)
- Sarah L Sokol
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Abby S Primack
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Sethu C Nair
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Zhee S Wong
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Maiwase Tembo
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, United States
| | - Shiv K Verma
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, United States
| | - Camila K Cerqueira-Cezar
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, United States
| | - J P Dubey
- Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, United States
| | - Jon P Boyle
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, United States
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Adomako-Ankomah Y, English ED, Danielson JJ, Pernas LF, Parker ML, Boulanger MJ, Dubey JP, Boyle JP. Host Mitochondrial Association Evolved in the Human Parasite Toxoplasma gondii via Neofunctionalization of a Gene Duplicate. Genetics 2016; 203:283-98. [PMID: 26920761 DOI: 10.1534/genetics.115.186270] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/14/2016] [Indexed: 01/30/2023] Open
Abstract
In Toxoplasma gondii, an intracellular parasite of humans and other animals, host mitochondrial association (HMA) is driven by a gene family that encodes multiple mitochondrial association factor 1 (MAF1) proteins. However, the importance of MAF1 gene duplication in the evolution of HMA is not understood, nor is the impact of HMA on parasite biology. Here we used within- and between-species comparative analysis to determine that the MAF1 locus is duplicated in T. gondii and its nearest extant relative Hammondia hammondi, but not another close relative, Neospora caninum. Using cross-species complementation, we determined that the MAF1 locus harbors multiple distinct paralogs that differ in their ability to mediate HMA, and that only T. gondii and H. hammondi harbor HMA+ paralogs. Additionally, we found that exogenous expression of an HMA+ paralog in T. gondii strains that do not normally exhibit HMA provides a competitive advantage over their wild-type counterparts during a mouse infection. These data indicate that HMA likely evolved by neofunctionalization of a duplicate MAF1 copy in the common ancestor of T. gondii and H. hammondi, and that the neofunctionalized gene duplicate is selectively advantageous.
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