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Howell J, Omwenga S, Jimenez M, Hammarton TC. Analysis of the Leishmania mexicana promastigote cell cycle using imaging flow cytometry provides new insights into cell cycle flexibility and events of short duration. PLoS One 2024; 19:e0311367. [PMID: 39361666 PMCID: PMC11449296 DOI: 10.1371/journal.pone.0311367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Accepted: 09/17/2024] [Indexed: 10/05/2024] Open
Abstract
Promastigote Leishmania mexicana have a complex cell division cycle characterised by the ordered replication of several single-copy organelles, a prolonged S phase and rapid G2 and cytokinesis phases, accompanied by cell cycle stage-associated morphological changes. Here we exploit these morphological changes to develop a high-throughput and semi-automated imaging flow cytometry (IFC) pipeline to analyse the cell cycle in live L. mexicana. Firstly, we demonstrate that, unlike several other DNA stains, Vybrant™ DyeCycle™ Orange (DCO) is non-toxic and enables quantitative DNA imaging in live promastigotes. Secondly, by tagging the orphan spindle kinesin, KINF, with mNeonGreen, we describe KINF's cell cycle-dependent expression and localisation. Then, by combining manual gating of DCO DNA intensity profiles with automated masking and morphological measurements of parasite images, visual determination of the number of flagella per cell, and automated masking and analysis of mNG:KINF fluorescence, we provide a newly detailed description of L. mexicana promastigote cell cycle events that, for the first time, includes the durations of individual G2, mitosis and post-mitosis phases, and identifies G1 cells within the first 12 minutes of the new cell cycle. Our custom-developed masking and gating scheme allowed us to identify elusive G2 cells and to demonstrate that the CDK-inhibitor, flavopiridol, arrests cells in G2 phase, rather than mitosis, providing proof-of-principle of the utility of IFC for drug mechanism-of-action studies. Further, the high-throughput nature of IFC allowed the close examination of promastigote cytokinesis, revealing considerable flexibility in both the timing of cytokinesis initiation and the direction of furrowing, in contrast to the related kinetoplastid parasite, Trypanosoma brucei and many other cell types. Our new pipeline offers many advantages over traditional methods of cell cycle analysis such as fluorescence microscopy and flow cytometry and paves the way for novel high-throughput analysis of Leishmania cell division.
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Affiliation(s)
- Jessie Howell
- James Watt School of Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Sulochana Omwenga
- School of Infection and Immunity, University of Glasgow, Glasgow, United Kingdom
| | - Melanie Jimenez
- Biomedical Engineering Department, University of Strathclyde, Glasgow, United Kingdom
| | - Tansy C. Hammarton
- School of Infection and Immunity, University of Glasgow, Glasgow, United Kingdom
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Peacock L, Kay C, Bailey M, Gibson W. Experimental genetic crosses in tsetse flies of the livestock pathogen Trypanosoma congolense savannah. Parasit Vectors 2024; 17:4. [PMID: 38178172 PMCID: PMC10765672 DOI: 10.1186/s13071-023-06105-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 12/17/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND In tropical Africa animal trypanosomiasis is a disease that has severe impacts on the health and productivity of livestock in tsetse fly-infested regions. Trypanosoma congolense savannah (TCS) is one of the main causative agents and is widely distributed across the sub-Saharan tsetse belt. Population genetics analysis has shown that TCS is genetically heterogeneous and there is evidence for genetic exchange, but to date Trypanosoma brucei is the only tsetse-transmitted trypanosome with experimentally proven capability to undergo sexual reproduction, with meiosis and production of haploid gametes. In T. brucei sex occurs in the fly salivary glands, so by analogy, sex in TCS should occur in the proboscis, where the corresponding portion of the developmental cycle takes place. Here we test this prediction using genetically modified red and green fluorescent clones of TCS. METHODS Three fly-transmissible strains of TCS were transfected with genes for red or green fluorescent protein, linked to a gene for resistance to the antibiotic hygromycin, and experimental crosses were set up by co-transmitting red and green fluorescent lines in different combinations via tsetse flies, Glossina pallidipes. To test whether sex occurred in vitro, co-cultures of attached epimastigotes of one red and one green fluorescent TCS strain were set up and sampled at intervals for 28 days. RESULTS All interclonal crosses of genetically modified trypanosomes produced hybrids containing both red and green fluorescent proteins, but yellow fluorescent hybrids were only present among trypanosomes from the fly proboscis, not from the midgut or proventriculus. It was not possible to identify the precise life cycle stage that undergoes mating, but it is probably attached epimastigotes in the food canal of the proboscis. Yellow hybrids were seen as early as 14 days post-infection. One intraclonal cross in tsetse and in vitro co-cultures of epimastigotes also produced yellow hybrids in small numbers. The hybrid nature of the yellow fluorescent trypanosomes observed was not confirmed by genetic analysis. CONCLUSIONS Despite absence of genetic characterisation of hybrid trypanosomes, the fact that these were produced only in the proboscis and in several independent crosses suggests that they are products of mating rather than cell fusion. The three-way strain compatibility observed is similar to that demonstrated previously for T. brucei, indicating that a simple two mating type system does not apply for either trypanosome species.
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Affiliation(s)
- Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
- Bristol Veterinary School, University of Bristol, Langford, Bristol, BS40 7DU, UK
| | - Chris Kay
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Mick Bailey
- Bristol Veterinary School, University of Bristol, Langford, Bristol, BS40 7DU, UK
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
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Sádlová J, Yeo M, Mateus DS, Phelan J, Hai LA, Bhattacharyya T, Kurtev S, Sebesta O, Myskova J, Seblova V, Andersson B, Florez de Sessions P, Volf P, Miles MA. Comparative genomics of Leishmania donovani progeny from genetic crosses in two sand fly species and impact on the diversity of diagnostic and vaccine candidates. PLoS Negl Trop Dis 2024; 18:e0011920. [PMID: 38295092 PMCID: PMC10830044 DOI: 10.1371/journal.pntd.0011920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 01/15/2024] [Indexed: 02/02/2024] Open
Abstract
Sand fly transmitted Leishmania species are responsible for severe, wide ranging, visceral and cutaneous leishmaniases. Genetic exchange can occur among natural Leishmania populations and hybrids can now be produced experimentally, with limitations. Feeding Phlebotomus orientalis or Phlebotomus argentipes on two strains of Leishmania donovani yielded hybrid progeny, selected using double drug resistance and fluorescence markers. Fluorescence activated cell sorting of cultured clones derived from these hybrids indicated diploid progeny. Multilocus sequence typing of the clones showed hybridisation and nuclear heterozygosity, although with inheritance of single haplotypes in a kinetoplastid target. Comparative genomics showed diversity of clonal progeny between single chromosomes, and extraordinary heterozygosity across all 36 chromosomes. Diversity between progeny was seen for the HASPB antigen, which has been noted previously as having implications for design of a therapeutic vaccine. Genomic diversity seen among Leishmania strains and hybrid progeny is of great importance in understanding the epidemiology and control of leishmaniasis. As an outcome of this study we strongly recommend that wider biological archives of different Leishmania species from endemic regions should be established and made available for comparative genomics. However, in parallel, performance of genetic crosses and genomic comparisons should give fundamental insight into the specificity, diversity and limitations of candidate diagnostics, vaccines and drugs, for targeted control of leishmaniasis.
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Affiliation(s)
- Jovana Sádlová
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Matthew Yeo
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London United Kingdom
| | - David S. Mateus
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London United Kingdom
| | - Jody Phelan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London United Kingdom
| | - Le Anh Hai
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London United Kingdom
| | - Tapan Bhattacharyya
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London United Kingdom
| | - Stefan Kurtev
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London United Kingdom
| | - Ondrej Sebesta
- Laboratory of Confocal and Fluorescence Microscopy, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jitka Myskova
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Veronika Seblova
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Björn Andersson
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Paola Florez de Sessions
- Genome Institute of Singapore, Biomedical Sciences Institutes, Agency for Science, Technology and Research, Singapore
| | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michael A. Miles
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London United Kingdom
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Catta-Preta CMC, Ferreira TR, Ghosh K, Paun A, Sacks D. HOP1 and HAP2 are conserved components of the meiosis-related machinery required for successful mating in Leishmania. Nat Commun 2023; 14:7159. [PMID: 37935664 PMCID: PMC10630298 DOI: 10.1038/s41467-023-42789-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/21/2023] [Indexed: 11/09/2023] Open
Abstract
Whole genome analysis of Leishmania hybrids generated experimentally in sand flies supports a meiotic mechanism of genetic exchange, with Mendelian segregation of the nuclear genome. Here, we perform functional analyses through the generation of double drug-resistant hybrids in vitro and in vivo (during sand fly infections) to assess the importance of conserved meiosis-related genes in recombination and plasmogamy. We report that HOP1 and a HAP2-paralog (HAP2-2) are essential components of the Leishmania meiosis machinery and cell-to-cell fusion mechanism, respectively, since deletion of either gene in one or both parents significantly reduces or completely abrogates mating competence. These findings significantly advance our understanding of sexual reproduction in Leishmania, with likely relevance to other trypanosomatids, by formally demonstrating the involvement of a meiotic protein homolog and a distinct fusogen that mediates non-canonical, bilateral fusion in the hybridizing cells.
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Affiliation(s)
- Carolina Moura Costa Catta-Preta
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tiago Rodrigues Ferreira
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kashinath Ghosh
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Andrea Paun
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David Sacks
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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Amodeo S, Bregy I, Ochsenreiter T. Mitochondrial genome maintenance-the kinetoplast story. FEMS Microbiol Rev 2023; 47:fuac047. [PMID: 36449697 PMCID: PMC10719067 DOI: 10.1093/femsre/fuac047] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 08/13/2022] [Accepted: 11/24/2022] [Indexed: 12/17/2023] Open
Abstract
Mitochondrial DNA replication is an essential process in most eukaryotes. Similar to the diversity in mitochondrial genome size and organization in the different eukaryotic supergroups, there is considerable diversity in the replication process of the mitochondrial DNA. In this review, we summarize the current knowledge of mitochondrial DNA replication and the associated factors in trypanosomes with a focus on Trypanosoma brucei, and provide a new model of minicircle replication for this protozoan parasite. The model assumes the mitochondrial DNA (kinetoplast DNA, kDNA) of T. brucei to be loosely diploid in nature and the replication of the genome to occur at two replication centers at the opposing ends of the kDNA disc (also known as antipodal sites, APS). The new model is consistent with the localization of most replication factors and in contrast to the current model, it does not require the assumption of an unknown sorting and transport complex moving freshly replicated DNA to the APS. In combination with the previously proposed sexual stages of the parasite in the insect vector, the new model provides a mechanism for maintenance of the mitochondrial genetic diversity.
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Affiliation(s)
- Simona Amodeo
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Hochschulstrasse 6, 3012 Bern, Switzerland
| | - Irina Bregy
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Hochschulstrasse 6, 3012 Bern, Switzerland
| | - Torsten Ochsenreiter
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland
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Peacock L, Kay C, Collett C, Bailey M, Gibson W. Development of the livestock pathogen Trypanosoma (Nannomonas) simiae in the tsetse fly with description of putative sexual stages from the proboscis. Parasit Vectors 2023; 16:231. [PMID: 37434196 DOI: 10.1186/s13071-023-05847-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/22/2023] [Indexed: 07/13/2023] Open
Abstract
BACKGROUND Tsetse-transmitted African animal trypanosomiasis is recognised as an important disease of ruminant livestock in sub-Saharan Africa, but also affects domestic pigs, with Trypanosoma simiae notable as a virulent suid pathogen that can rapidly cause death. Trypanosoma simiae is widespread in tsetse-infested regions, but its biology has been little studied compared to T. brucei and T. congolense. METHODS Trypanosoma simiae procyclics were cultured in vitro and transfected using protocols developed for T. brucei. Genetically modified lines, as well as wild-type trypanosomes, were transmitted through tsetse flies, Glossina pallidipes, to study T. simiae development in the tsetse midgut, proventriculus and proboscis. The development of proventricular trypanosomes was also studied in vitro. Image and mensural data were collected and analysed. RESULTS A PFR1::YFP line successfully completed development in tsetse, but a YFP::HOP1 line failed to progress beyond midgut infection. Analysis of image and mensural data confirmed that the vector developmental cycles of T. simiae and T. congolense are closely similar, but we also found putative sexual stages in T. simiae, as judged by morphological similarity to these stages in T. brucei. Putative meiotic dividers were abundant among T. simiae trypanosomes in the proboscis, characterised by a large posterior nucleus and two anterior kinetoplasts. Putative gametes and other meiotic intermediates were also identified by characteristic morphology. In vitro development of proventricular forms of T. simiae followed the pattern previously observed for T. congolense: long proventricular trypanosomes rapidly attached to the substrate and shortened markedly before commencing cell division. CONCLUSIONS To date, T. brucei is the only tsetse-transmitted trypanosome with experimentally proven capability to undergo sexual reproduction, which occurs in the fly salivary glands. By analogy, sexual stages of T. simiae or T. congolense are predicted to occur in the proboscis, where the corresponding portion of the developmental cycle takes place. While no such stages have been observed in T. congolense, for T. simiae putative sexual stages were abundant in the tsetse proboscis. Although our initial attempt to demonstrate expression of a YFP-tagged, meiosis-specific protein was unsuccessful, the future application of transgenic approaches will facilitate the identification of meiotic stages and hybrids in T. simiae.
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Affiliation(s)
- Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
- Bristol Veterinary School, University of Bristol, Langford, Bristol, BS40 7DU, UK
| | - Chris Kay
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Clare Collett
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
- Pathogen Immunology Group, UK Health Security Agency, Porton Down, Salisbury, SP4 0JG, Wiltshire, UK
| | - Mick Bailey
- Bristol Veterinary School, University of Bristol, Langford, Bristol, BS40 7DU, UK
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
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Won MM, Baublis A, Burleigh BA. Proximity-dependent biotinylation and identification of flagellar proteins in Trypanosoma cruzi. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528900. [PMID: 36824716 PMCID: PMC9949143 DOI: 10.1101/2023.02.16.528900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The flagellated kinetoplastid protozoan and causative agent of human Chagas disease, Trypanosoma cruzi , inhabits both invertebrate and mammalian hosts over the course of its complex life cycle. In these disparate environments, T. cruzi uses its single flagellum to propel motile life stages and in some instances, to establish intimate contact with the host. Beyond its role in motility, the functional capabilities of the T. cruzi flagellum have not been defined. Moreover, the lack of proteomic information for this organelle, in any parasite life stage, has limited functional investigation. In this study, we employed a proximity-dependent biotinylation approach based on the differential targeting of the biotin ligase, TurboID, to the flagellum or cytosol in replicative stages of T. cruzi , to identify flagellar-enriched proteins by mass spectrometry. Proteomic analysis of the resulting biotinylated protein fractions yielded 218 candidate flagellar proteins in T. cruzi epimastigotes (insect stage) and 99 proteins in intracellular amastigotes (mammalian stage). Forty of these flagellar-enriched proteins were common to both parasite life stages and included orthologs of known flagellar proteins in other trypanosomatid species, proteins specific to the T. cruzi lineage and hypothetical proteins. With the validation of flagellar localization for several of the identified candidates, our results demonstrate that TurboID-based proximity proteomics is an effective tool for probing subcellular compartments in T. cruzi . The proteomic datasets generated in this work offer a valuable resource to facilitate functional investigation of the understudied T. cruzi flagellum.
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Affiliation(s)
- Madalyn M Won
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health Boston, MA 02115, USA
| | - Aaron Baublis
- Harvard Chan Advanced Multi-omics Platform, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Barbara A Burleigh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health Boston, MA 02115, USA
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da Silva VS, Machado CR. Sex in protists: A new perspective on the reproduction mechanisms of trypanosomatids. Genet Mol Biol 2022; 45:e20220065. [PMID: 36218381 PMCID: PMC9552303 DOI: 10.1590/1678-4685-gmb-2022-0065] [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: 02/28/2022] [Accepted: 08/07/2022] [Indexed: 11/04/2022] Open
Abstract
The Protist kingdom individuals are the most ancestral representatives of eukaryotes. They have inhabited Earth since ancient times and are currently found in the most diverse environments presenting a great heterogeneity of life forms. The unicellular and multicellular algae, photosynthetic and heterotrophic organisms, as well as free-living and pathogenic protozoa represents the protist group. The evolution of sex is directly associated with the origin of eukaryotes being protists the earliest protagonists of sexual reproduction on earth. In eukaryotes, the recombination through genetic exchange is a ubiquitous mechanism that can be stimulated by DNA damage. Scientific evidences support the hypothesis that reactive oxygen species (ROS) induced DNA damage can promote sexual recombination in eukaryotes which might have been a decisive factor for the origin of sex. The fact that some recombination enzymes also participate in meiotic sex in modern eukaryotes reinforces the idea that sexual reproduction emerged as consequence of specific mechanisms to cope with mutations and alterations in genetic material. In this review we will discuss about origin of sex and different strategies of evolve sexual reproduction in some protists such that cause human diseases like malaria, toxoplasmosis, sleeping sickness, Chagas disease, and leishmaniasis.
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Affiliation(s)
- Verônica Santana da Silva
- Universidade Federal de Minas Gerais, Departamento de Genética,
Ecologia e Evolução, Belo Horizonte, MG, Brazil
| | - Carlos Renato Machado
- Universidade Federal de Minas Gerais, Departamento de Bioquímica e
Imunologia, Belo Horizonte, MG, Brazil
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Kent RS, Briggs EM, Colon BL, Alvarez C, Silva Pereira S, De Niz M. Paving the Way: Contributions of Big Data to Apicomplexan and Kinetoplastid Research. Front Cell Infect Microbiol 2022; 12:900878. [PMID: 35734575 PMCID: PMC9207352 DOI: 10.3389/fcimb.2022.900878] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/06/2022] [Indexed: 11/13/2022] Open
Abstract
In the age of big data an important question is how to ensure we make the most out of the resources we generate. In this review, we discuss the major methods used in Apicomplexan and Kinetoplastid research to produce big datasets and advance our understanding of Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania biology. We debate the benefits and limitations of the current technologies, and propose future advancements that may be key to improving our use of these techniques. Finally, we consider the difficulties the field faces when trying to make the most of the abundance of data that has already been, and will continue to be, generated.
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Affiliation(s)
- Robyn S. Kent
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, United States
| | - Emma M. Briggs
- Institute for Immunology and Infection Research, School of Biological Sciences, University Edinburgh, Edinburgh, United Kingdom
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Beatrice L. Colon
- Wellcome Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Catalina Alvarez
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Sara Silva Pereira
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Mariana De Niz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
- Institut Pasteur, Paris, France
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10
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Sáez Conde J, Dean S. Structure, function and druggability of the African trypanosome flagellum. J Cell Physiol 2022; 237:2654-2667. [PMID: 35616248 PMCID: PMC9323424 DOI: 10.1002/jcp.30778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022]
Abstract
African trypanosomes are early branching protists that cause human and animal diseases, termed trypanosomiases. They have been under intensive study for more than 100 years and have contributed significantly to our understanding of eukaryotic biology. The combination of conserved and parasite-specific features mean that their flagellum has gained particular attention. Here, we discuss the different structural features of the flagellum and their role in transmission and virulence. We highlight the possibilities of targeting flagellar function to cure trypanosome infections and help in the fight to eliminate trypanosomiases.
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Affiliation(s)
- Julia Sáez Conde
- Division of Biomedical Sciences, Warwick Medical SchoolUniversity of WarwickCoventryUK
| | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical SchoolUniversity of WarwickCoventryUK
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11
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Kasozi KI, MacLeod ET, Ntulume I, Welburn SC. An Update on African Trypanocide Pharmaceutics and Resistance. Front Vet Sci 2022; 9:828111. [PMID: 35356785 PMCID: PMC8959112 DOI: 10.3389/fvets.2022.828111] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/12/2022] [Indexed: 12/22/2022] Open
Abstract
African trypanosomiasis is associated with Trypanosoma evansi, T. vivax, T. congolense, and T. brucei pathogens in African animal trypanosomiasis (AAT) while T. b gambiense and T. b rhodesiense are responsible for chronic and acute human African trypanosomiasis (HAT), respectively. Suramin sodium suppresses ATP generation during the glycolytic pathway and is ineffective against T. vivax and T. congolense infections. Resistance to suramin is associated with pathogen altered transport proteins. Melarsoprol binds irreversibly with pyruvate kinase protein sulfhydryl groups and neutralizes enzymes which interrupts the trypanosome ATP generation. Melarsoprol resistance is associated with the adenine-adenosine transporter, P2, due to point mutations within this transporter. Eflornithine is used in combination with nifurtimox. Resistance to eflornithine is caused by the deletion or mutation of TbAAT6 gene which encodes the transmembrane amino acid transporter that delivers eflornithine into the cell, thus loss of transporter protein results in eflornithine resistance. Nifurtimox alone is regarded as a poor trypanocide, however, it is effective in melarsoprol-resistant gHAT patients. Resistance is associated with loss of a single copy of the genes encoding for nitroreductase enzymes. Fexinidazole is recommended for first-stage and non-severe second-stage illnesses in gHAT and resistance is associated with trypanosome bacterial nitroreductases which reduce fexinidazole. In AAT, quinapyramine sulfate interferes with DNA synthesis and suppression of cytoplasmic ribosomal activity in the mitochondria. Quinapyramine sulfate resistance is due to variations in the potential of the parasite's mitochondrial membrane. Pentamidines create cross-links between two adenines at 4–5 pairs apart in adenine-thymine-rich portions of Trypanosoma DNA. It also suppresses type II topoisomerase in the mitochondria of Trypanosoma parasites. Pentamidine resistance is due to loss of mitochondria transport proteins P2 and HAPT1. Diamidines are most effective against Trypanosome brucei group and act via the P2/TbAT1 transporters. Diminazene aceturate resistance is due to mutations that alter the activity of P2, TeDR40 (T. b. evansi). Isometamidium chloride is primarily employed in the early stages of trypanosomiasis and resistance is associated with diminazene resistance. Phenanthridine (homidium bromide, also known as ethidium bromide) acts by a breakdown of the kinetoplast network and homidium resistance is comparable to isometamidium. In humans, the development of resistance and adverse side effects against monotherapies has led to the adoption of nifurtimox-eflornithine combination therapy. Current efforts to develop new prodrug combinations of nifurtimox and eflornithine and nitroimidazole fexinidazole as well as benzoxaborole SCYX-7158 (AN5568) for HAT are in progress while little comparable progress has been done for the development of novel therapies to address trypanocide resistance in AAT.
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Affiliation(s)
- Keneth Iceland Kasozi
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- School of Medicine, Kabale University, Kabale, Uganda
- *Correspondence: Keneth Iceland Kasozi ;
| | - Ewan Thomas MacLeod
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ibrahim Ntulume
- School of Biosecurity Biotechnical and Laboratory Sciences, College of Medicine and Veterinary Medicine, Makerere University, Kampala, Uganda
| | - Susan Christina Welburn
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- Zhejiang University-University of Edinburgh Joint Institute, Zhejiang University, Hangzhou, China
- Susan Christina Welburn
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12
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Howick VM, Peacock L, Kay C, Collett C, Gibson W, Lawniczak MKN. Single-cell transcriptomics reveals expression profiles of Trypanosoma brucei sexual stages. PLoS Pathog 2022; 18:e1010346. [PMID: 35255094 PMCID: PMC8939820 DOI: 10.1371/journal.ppat.1010346] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/22/2022] [Accepted: 02/06/2022] [Indexed: 01/26/2023] Open
Abstract
Early diverging lineages such as trypanosomes can provide clues to the evolution of sexual reproduction in eukaryotes. In Trypanosoma brucei, the pathogen that causes Human African Trypanosomiasis, sexual reproduction occurs in the salivary glands of the insect host, but analysis of the molecular signatures that define these sexual forms is complicated because they mingle with more numerous, mitotically-dividing developmental stages. We used single-cell RNA-sequencing (scRNAseq) to profile 388 individual trypanosomes from midgut, proventriculus, and salivary glands of infected tsetse flies allowing us to identify tissue-specific cell types. Further investigation of salivary gland parasite transcriptomes revealed fine-scale changes in gene expression over a developmental progression from putative sexual forms through metacyclics expressing variant surface glycoprotein genes. The cluster of cells potentially containing sexual forms was characterized by high level transcription of the gamete fusion protein HAP2, together with an array of surface proteins and several genes of unknown function. We linked these expression patterns to distinct morphological forms using immunofluorescence assays and reporter gene expression to demonstrate that the kinetoplastid-conserved gene Tb927.10.12080 is exclusively expressed at high levels by meiotic intermediates and gametes. Further experiments are required to establish whether this protein, currently of unknown function, plays a role in gamete formation and/or fusion.
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Affiliation(s)
- Virginia M. Howick
- Institute of Biodiversity, Animal Health, and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- Parasites and Microbes Programme, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- Bristol Veterinary School, University of Bristol, Langford, United Kingdom
| | - Chris Kay
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Clare Collett
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Mara K. N. Lawniczak
- Parasites and Microbes Programme, Wellcome Sanger Institute, Hinxton, United Kingdom
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13
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Kay C, Peacock L, Williams TA, Gibson W. Signatures of hybridization in Trypanosoma brucei. PLoS Pathog 2022; 18:e1010300. [PMID: 35139131 PMCID: PMC8863249 DOI: 10.1371/journal.ppat.1010300] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 02/22/2022] [Accepted: 01/22/2022] [Indexed: 11/19/2022] Open
Abstract
Genetic exchange among disease-causing micro-organisms can generate progeny that combine different pathogenic traits. Though sexual reproduction has been described in trypanosomes, its impact on the epidemiology of Human African Trypanosomiasis (HAT) remains controversial. However, human infective and non-human infective strains of Trypanosoma brucei circulate in the same transmission cycles in HAT endemic areas in subsaharan Africa, providing the opportunity for mating during the developmental cycle in the tsetse fly vector. Here we investigated inheritance among progeny from a laboratory cross of T. brucei and then applied these insights to genomic analysis of field-collected isolates to identify signatures of past genetic exchange. Genomes of two parental and four hybrid progeny clones with a range of DNA contents were assembled and analysed by k-mer and single nucleotide polymorphism (SNP) frequencies to determine heterozygosity and chromosomal inheritance. Variant surface glycoprotein (VSG) genes and kinetoplast (mitochondrial) DNA maxi- and minicircles were extracted from each genome to examine how each of these components was inherited in the hybrid progeny. The same bioinformatic approaches were applied to an additional 37 genomes representing the diversity of T. brucei in subsaharan Africa and T. evansi. SNP analysis provided evidence of crossover events affecting all 11 pairs of megabase chromosomes and demonstrated that polyploid hybrids were formed post-meiotically and not by fusion of the parental diploid cells. VSGs and kinetoplast DNA minicircles were inherited biparentally, with approximately equal numbers from each parent, whereas maxicircles were inherited uniparentally. Extrapolation of these findings to field isolates allowed us to distinguish clonal descent from hybridization by comparing maxicircle genotype to VSG and minicircle repertoires. Discordance between maxicircle genotype and VSG and minicircle repertoires indicated inter-lineage hybridization. Significantly, some of the hybridization events we identified involved human infective and non-human infective trypanosomes circulating in the same geographic areas.
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Affiliation(s)
- Christopher Kay
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- Bristol Veterinary School, University of Bristol, Bristol, United Kingdom
| | - Tom A. Williams
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
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14
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Gutiérrez-Corbo C, Domínguez-Asenjo B, Pérez-Pertejo Y, García-Estrada C, Bello FJ, Balaña-Fouce R, Reguera RM. Axenic interspecies and intraclonal hybrid formation in Leishmania: Successful crossings between visceral and cutaneous strains. PLoS Negl Trop Dis 2022; 16:e0010170. [PMID: 35139072 PMCID: PMC8827483 DOI: 10.1371/journal.pntd.0010170] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 01/13/2022] [Indexed: 12/29/2022] Open
Abstract
Diseases caused by trypanosomatids are serious public health concerns in low-income endemic countries. Leishmaniasis is presented in two main clinical forms, visceral leishmaniasis-caused by L. infantum and L. donovani-and cutaneous leishmaniasis-caused by many species, including L. major, L. tropica and L. braziliensis. As for certain other trypanosomatids, sexual reproduction has been confirmed in these parasites, and formation of hybrids can contribute to virulence, drug resistance or adaptation to the host immune system. In the present work, the capability of intraclonal and interspecies genetic exchange has been investigated using three parental strains: L. donovani, L. tropica and L. major, which have been engineered to express different fluorescent proteins and antibiotic resistance markers in order to facilitate the phenotypic selection of hybrid parasites after mating events. Stationary and exponential-phase promastigotes of each species were used, in in vitro experiments, some of them containing LULO cells (an embryonic cell line derived from Lutzomyia longipalpis). Several intraclonal hybrids were obtained with L. tropica as crossing progenitor, but not with L. donovani or L. major. In interspecies crossings, three L. donovani x L. major hybrids and two L. donovani x L. tropica hybrids were isolated, thereby demonstrating the feasibility to obtain in vitro hybrids of parental lines causing different tropism of leishmaniasis. Ploidy analysis revealed an increase in DNA content in all hybrids compared to the parental strains, and nuclear analysis showed that interspecies hybrids are complete hybrids, i.e. each of them showing at least one chromosomal set from each parental. Regarding kDNA inheritance, discrepancies were observed between maxi and minicircle heritage. Finally, phenotypic studies showed either intermediate phenotypes in terms of growth profiles, or a decreased in vitro infection capacity compared to the parental cells. To the best of our knowledge, this is the first time that in vitro interspecies outcrossing has been demonstrated between Leishmania species with different tropism, thus contributing to shed light on the mechanisms underlying sexual reproduction in these parasites.
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Affiliation(s)
- Camino Gutiérrez-Corbo
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
| | | | - Yolanda Pérez-Pertejo
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
| | - Carlos García-Estrada
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
| | - Felio J Bello
- Facultad de Ciencias Agropecuarias, Programa de Medicina Veterinaria, Universidad de la Salle, Bogotá, Colombia
| | - Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
- * E-mail: (RB-F); (RMR)
| | - Rosa M. Reguera
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
- * E-mail: (RB-F); (RMR)
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15
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Pinello JF, Clark TG. HAP2-Mediated Gamete Fusion: Lessons From the World of Unicellular Eukaryotes. Front Cell Dev Biol 2022; 9:807313. [PMID: 35071241 PMCID: PMC8777248 DOI: 10.3389/fcell.2021.807313] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 01/29/2023] Open
Abstract
Most, if not all the cellular requirements for fertilization and sexual reproduction arose early in evolution and are retained in extant lineages of single-celled organisms including a number of important model organism species. In recent years, work in two such species, the green alga, Chlamydomonas reinhardtii, and the free-living ciliate, Tetrahymena thermophila, have lent important new insights into the role of HAP2/GCS1 as a catalyst for gamete fusion in organisms ranging from protists to flowering plants and insects. Here we summarize the current state of knowledge around how mating types from these algal and ciliate systems recognize, adhere and fuse to one another, current gaps in our understanding of HAP2-mediated gamete fusion, and opportunities for applying what we know in practical terms, especially for the control of protozoan parasites.
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Affiliation(s)
- Jennifer F. Pinello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, United States
| | - Theodore G. Clark
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY, United States
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16
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Louradour I, Ferreira TR, Duge E, Karunaweera N, Paun A, Sacks D. Stress conditions promote Leishmania hybridization in vitro marked by expression of the ancestral gamete fusogen HAP2 as revealed by single-cell RNA-seq. eLife 2022; 11:73488. [PMID: 34994687 PMCID: PMC8794473 DOI: 10.7554/elife.73488] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/06/2022] [Indexed: 12/18/2022] Open
Abstract
Leishmania are protozoan parasites transmitted by the bite of sand fly vectors producing a wide spectrum of diseases in their mammalian hosts. These diverse clinical outcomes are directly associated with parasite strain and species diversity. Although Leishmania reproduction is mainly clonal, a cryptic sexual cycle capable of producing hybrid genotypes has been inferred from population genetic studies and directly demonstrated by laboratory crosses. Experimentally, mating competence has been largely confined to promastigotes developing in the sand fly midgut. The ability to hybridize culture promastigotes in vitro has been limited so far to low-efficiency crosses between two Leishmania tropica strains, L747 and MA37, that mate with high efficiency in flies. Here, we show that exposure of promastigote cultures to DNA damage stress produces a remarkably enhanced efficiency of in vitro hybridization of the L. tropica strains and extends to other species, including Leishmania donovani, Leishmania infantum, and Leishmania braziliensis, a capacity to generate intra- and interspecific hybrids. Whole-genome sequencing and total DNA content analyses indicate that the hybrids are in each case full genome, mostly tetraploid hybrids. Single-cell RNA sequencing of the L747 and MA37 parental lines highlights the transcriptome heterogeneity of culture promastigotes and reveals discrete clusters that emerge post-irradiation in which genes potentially involved in genetic exchange are expressed, including the ancestral gamete fusogen HAP2. By generating reporter constructs for HAP2, we could select for promastigotes that could either hybridize or not in vitro. Overall, this work reveals that there are specific populations involved in Leishmania hybridization associated with a discernible transcriptomic signature, and that stress facilitated in vitro hybridization can be a transformative approach to generate large numbers of hybrid genotypes between diverse species and strains.
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Affiliation(s)
- Isabelle Louradour
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Tiago Rodrigues Ferreira
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Emma Duge
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Nadira Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Andrea Paun
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - David Sacks
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
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17
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Medina-Rincón GJ, Gallo-Bernal S, Jiménez PA, Cruz-Saavedra L, Ramírez JD, Rodríguez MJ, Medina-Mur R, Díaz-Nassif G, Valderrama-Achury MD, Medina HM. Molecular and Clinical Aspects of Chronic Manifestations in Chagas Disease: A State-of-the-Art Review. Pathogens 2021; 10:pathogens10111493. [PMID: 34832648 PMCID: PMC8619182 DOI: 10.3390/pathogens10111493] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 12/11/2022] Open
Abstract
Chronic manifestations of Chagas disease present as disabling and life-threatening conditions affecting mainly the cardiovascular and gastrointestinal systems. Although meaningful research has outlined the different molecular mechanisms underlying Trypanosoma cruzi’s infection and the host-parasite interactions that follow, prompt diagnosis and treatment remain a challenge, particularly in developing countries and also in those where the disease is considered non-endemic. This review intends to present an up-to-date review of the parasite’s life cycle, genetic diversity, virulence factors, and infective mechanisms, as well as the epidemiology, clinical presentation, diagnosis, and treatment options of the main chronic complications of Chagas disease.
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Affiliation(s)
- Germán J. Medina-Rincón
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (S.G.-B.); (M.D.V.-A.); (H.M.M.)
- Correspondence: ; Tel.: +57-310-817-2369
| | - Sebastián Gallo-Bernal
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (S.G.-B.); (M.D.V.-A.); (H.M.M.)
- Department of Radiology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Radiology, Harvard Medical School, Boston, MA 02114, USA
| | - Paula A. Jiménez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá 111221, Colombia; (P.A.J.); (L.C.-S.); (J.D.R.)
| | - Lissa Cruz-Saavedra
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá 111221, Colombia; (P.A.J.); (L.C.-S.); (J.D.R.)
| | - Juan David Ramírez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá 111221, Colombia; (P.A.J.); (L.C.-S.); (J.D.R.)
| | - María Juliana Rodríguez
- Division of Cardiology, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá 110131, Colombia; (M.J.R.); (R.M.-M.)
| | - Ramón Medina-Mur
- Division of Cardiology, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá 110131, Colombia; (M.J.R.); (R.M.-M.)
| | - Gustavo Díaz-Nassif
- Division of Gastroenterology and Liver Diseases, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá 111221, Colombia;
| | | | - Héctor M. Medina
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia; (S.G.-B.); (M.D.V.-A.); (H.M.M.)
- Division of Cardiology, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá 110131, Colombia; (M.J.R.); (R.M.-M.)
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18
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Cosentino RO, Brink BG, Siegel TN. Allele-specific assembly of a eukaryotic genome corrects apparent frameshifts and reveals a lack of nonsense-mediated mRNA decay. NAR Genom Bioinform 2021; 3:lqab082. [PMID: 34541528 PMCID: PMC8445201 DOI: 10.1093/nargab/lqab082] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/25/2021] [Accepted: 09/06/2021] [Indexed: 11/14/2022] Open
Abstract
To date, most reference genomes represent a mosaic consensus sequence in which the homologous chromosomes are collapsed into one sequence. This approach produces sequence artefacts and impedes analyses of allele-specific mechanisms. Here, we report an allele-specific genome assembly of the diploid parasite Trypanosoma brucei and reveal allelic variants affecting gene expression. Using long-read sequencing and chromosome conformation capture data, we could assign 99.5% of all heterozygote variants to a specific homologous chromosome and build a 66 Mb long allele-specific genome assembly. The phasing of haplotypes allowed us to resolve hundreds of artefacts present in the previous mosaic consensus assembly. In addition, it revealed allelic recombination events, visible as regions of low allelic heterozygosity, enabling the lineage tracing of T. brucei isolates. Interestingly, analyses of transcriptome and translatome data of genes with allele-specific premature termination codons point to the absence of a nonsense-mediated decay mechanism in trypanosomes. Taken together, this study delivers a reference quality allele-specific genome assembly of T. brucei and demonstrates the importance of such assemblies for the study of gene expression control. We expect the new genome assembly will increase the awareness of allele-specific phenomena and provide a platform to investigate them.
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Affiliation(s)
- Raúl O Cosentino
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität in Munich, Lena-Christ-Str. 48, Planegg-Martinsried 82152, Germany
| | - Benedikt G Brink
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität in Munich, Lena-Christ-Str. 48, Planegg-Martinsried 82152, Germany
| | - T Nicolai Siegel
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität in Munich, Lena-Christ-Str. 48, Planegg-Martinsried 82152, Germany
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19
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Hutchinson S, Foulon S, Crouzols A, Menafra R, Rotureau B, Griffiths AD, Bastin P. The establishment of variant surface glycoprotein monoallelic expression revealed by single-cell RNA-seq of Trypanosoma brucei in the tsetse fly salivary glands. PLoS Pathog 2021; 17:e1009904. [PMID: 34543350 PMCID: PMC8509897 DOI: 10.1371/journal.ppat.1009904] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/12/2021] [Accepted: 08/17/2021] [Indexed: 12/27/2022] Open
Abstract
The long and complex Trypanosoma brucei development in the tsetse fly vector culminates when parasites gain mammalian infectivity in the salivary glands. A key step in this process is the establishment of monoallelic variant surface glycoprotein (VSG) expression and the formation of the VSG coat. The establishment of VSG monoallelic expression is complex and poorly understood, due to the multiple parasite stages present in the salivary glands. Therefore, we sought to further our understanding of this phenomenon by performing single-cell RNA-sequencing (scRNA-seq) on these trypanosome populations. We were able to capture the developmental program of trypanosomes in the salivary glands, identifying populations of epimastigote, gamete, pre-metacyclic and metacyclic cells. Our results show that parasite metabolism is dramatically remodeled during development in the salivary glands, with a shift in transcript abundance from tricarboxylic acid metabolism to glycolytic metabolism. Analysis of VSG gene expression in pre-metacyclic and metacyclic cells revealed a dynamic VSG gene activation program. Strikingly, we found that pre-metacyclic cells contain transcripts from multiple VSG genes, which resolves to singular VSG gene expression in mature metacyclic cells. Single molecule RNA fluorescence in situ hybridisation (smRNA-FISH) of VSG gene expression following in vitro metacyclogenesis confirmed this finding. Our data demonstrate that multiple VSG genes are transcribed before a single gene is chosen. We propose a transcriptional race model governs the initiation of monoallelic expression. African trypanosomes are parasitic protists which cause endemic disease in sub-Saharan Africa. To evade mammalian immune responses the parasite has developed a system of antigenic variation, where the surface of the cell is covered in a tightly packed coat of variant surface glycoproteins (VSGs). Each cell expresses only one variant surface glycoprotein at a time, and this is periodically switched to evade new antibodies. The process of singular gene expression is termed monoallelic expression and this has two components, establishment and maintenance, i.e. how a single gene is selected for expression and how its singular expression is maintained throughout successive generations. The establishment of monoallelic VSG gene expression occurs in the salivary gland of the tsetse fly vector, although this process is not well understood. We used single cell gene expression profiling applied to thousands of single cells in the salivary gland of the fly. We show that in order to select a single gene, trypanosomes initially transcribe multiple VSGs before a single gene is selected for high-level expression. We propose a model where this process is driven by a race to accumulate transcription factors at a single VSG gene.
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Affiliation(s)
- Sebastian Hutchinson
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
- * E-mail:
| | - Sophie Foulon
- Laboratoire de Biochimie, CBI, ESPCI Paris, Université PSL, CNRS UMR 8231, Paris, France
| | - Aline Crouzols
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
| | - Roberta Menafra
- Laboratoire de Biochimie, CBI, ESPCI Paris, Université PSL, CNRS UMR 8231, Paris, France
| | - Brice Rotureau
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
| | - Andrew D. Griffiths
- Laboratoire de Biochimie, CBI, ESPCI Paris, Université PSL, CNRS UMR 8231, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
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20
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Naguleswaran A, Fernandes P, Bevkal S, Rehmann R, Nicholson P, Roditi I. Developmental changes and metabolic reprogramming during establishment of infection and progression of Trypanosoma brucei brucei through its insect host. PLoS Negl Trop Dis 2021; 15:e0009504. [PMID: 34543277 PMCID: PMC8483307 DOI: 10.1371/journal.pntd.0009504] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/30/2021] [Accepted: 09/07/2021] [Indexed: 02/07/2023] Open
Abstract
Trypanosoma brucei ssp., unicellular parasites causing human and animal trypanosomiasis, are transmitted between mammals by tsetse flies. Periodic changes in variant surface glycoproteins (VSG), which form the parasite coat in the mammal, allow them to evade the host immune response. Different isolates of T. brucei show heterogeneity in their repertoires of VSG genes and have single nucleotide polymorphisms and indels that can impact on genome editing. T. brucei brucei EATRO1125 (AnTaR1 serodeme) is an isolate that is used increasingly often because it is pleomorphic in mammals and fly transmissible, two characteristics that have been lost by the most commonly used laboratory stocks. We present a genome assembly of EATRO1125, including contigs for the intermediate chromosomes and minichromosomes that serve as repositories of VSG genes. In addition, de novo transcriptome assemblies were performed using Illumina sequences from tsetse-derived trypanosomes. Reads of 150 bases enabled closely related members of multigene families to be discriminated. This revealed that the transcriptome of midgut-derived parasites is dynamic, starting with the expression of high affinity hexose transporters and glycolytic enzymes and then switching to proline uptake and catabolism. These changes resemble the transition from early to late procyclic forms in culture. Further metabolic reprogramming, including upregulation of tricarboxylic acid cycle enzymes, occurs in the proventriculus. Many transcripts upregulated in the salivary glands encode surface proteins, among them 7 metacyclic VSGs, multiple BARPs and GCS1/HAP2, a marker for gametes. A novel family of transmembrane proteins, containing polythreonine stretches that are predicted to be O-glycosylation sites, was also identified. Finally, RNA-Seq data were used to create an optimised annotation file with 5’ and 3’ untranslated regions accurately mapped for 9302 genes. We anticipate that this will be of use in identifying transcripts obtained by single cell sequencing technologies. Trypanosoma brucei ssp. are single-celled parasites that cause two tropical diseases: sleeping sickness in humans and nagana in domestic animals. Parasites survive in the host bloodstream because they periodically change their surface coats and also because they can switch from slender dividing forms to stumpy non-dividing forms. The latter can be transmitted to their second host, the tsetse fly. Although closely related, different geographical isolates differ in their repertoire of surface coats and have small, but important differences in their DNA sequences. In addition, laboratory strains that are transferred between mammals by needle passage lose the ability to produce stumpy forms and to infect flies. The isolate T. b. brucei EATRO1125 is often used for research as it produces stumpy forms and is fly transmissible. We provide an assembly of the genome of this isolate, including part of the repertoire of coat proteins, and a detailed analysis of the genes that the parasites express as they establish infection and progress through the fly. This has provided new insights into trypanosome biology. The combined genomic (DNA) and transcriptomic (RNA) data will be useful resources for the trypanosome research community.
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Affiliation(s)
| | - Paula Fernandes
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Shubha Bevkal
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Ruth Rehmann
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Pamela Nicholson
- Next Generation Sequencing Platform, University of Bern, Bern, Switzerland
| | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- * E-mail:
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21
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Mulindwa J, Ssentamu G, Matovu E, Kamanyi Marucha K, Aresta-Branco F, Helbig C, Clayton C. In vitro culture of freshly isolated Trypanosoma brucei brucei bloodstream forms results in gene copy-number changes. PLoS Negl Trop Dis 2021; 15:e0009738. [PMID: 34516555 PMCID: PMC8459984 DOI: 10.1371/journal.pntd.0009738] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/23/2021] [Accepted: 08/17/2021] [Indexed: 11/19/2022] Open
Abstract
Most researchers who study unicellular eukaryotes work with an extremely limited number of laboratory-adapted isolates that were obtained from the field decades ago, but the effects of passage in laboratory rodents, and adaptation to in vitro culture, have been little studied. For example, the vast majority of studies of Trypanosoma brucei biology have concentrated on just two strains, Lister 427 and EATRO1125, which were taken from the field over half a century ago and have since have undergone innumerable passages in rodents and culture. We here describe two new Trypanosoma brucei brucei strains. MAK65 and MAK98, which have undergone only 3 rodent passages since isolation from Ugandan cattle. High-coverage sequencing revealed that adaptation of the parasites to culture was accompanied by changes in gene copy numbers. T. brucei has so far been considered to be uniformly diploid, but we also found trisomy of chromosome 5 not only in one Lister 427 culture, but also in the MAK98 field isolate. Trisomy of chromosome 6, and increased copies of other chromosome segments, were also seen in established cultured lines. The two new T. brucei strains should be useful to researchers interested in trypanosome differentiation and pathogenicity. Initial results suggested that the two strains have differing infection patterns in rodents. MAK65 is uniformly diploid and grew more reproducibly in bloodstream-form culture than MAK98.
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Affiliation(s)
- Julius Mulindwa
- Department of Biochemistry and Sports Science, College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Geofrey Ssentamu
- School of Biosecurity, Biotechnical and Laboratory Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Enock Matovu
- School of Biosecurity, Biotechnical and Laboratory Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | | | | | - Claudia Helbig
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Christine Clayton
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
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Dean S. Basic Biology of Trypanosoma brucei with Reference to the Development of Chemotherapies. Curr Pharm Des 2021; 27:1650-1670. [PMID: 33463458 DOI: 10.2174/1381612827666210119105008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 11/22/2022]
Abstract
Trypanosoma brucei are protozoan parasites that cause the lethal human disease African sleeping sickness and the economically devastating disease of cattle, Nagana. African sleeping sickness, also known as Human African Trypanosomiasis (HAT), threatens 65 million people and animal trypanosomiasis makes large areas of farmland unusable. There is no vaccine and licensed therapies against the most severe, late-stage disease are toxic, impractical and ineffective. Trypanosomes are transmitted by tsetse flies, and HAT is therefore predominantly confined to the tsetse fly belt in sub-Saharan Africa. They are exclusively extracellular and they differentiate between at least seven developmental forms that are highly adapted to host and vector niches. In the mammalian (human) host they inhabit the blood, cerebrospinal fluid (late-stage disease), skin, and adipose fat. In the tsetse fly vector they travel from the tsetse midgut to the salivary glands via the ectoperitrophic space and proventriculus. Trypanosomes are evolutionarily divergent compared with most branches of eukaryotic life. Perhaps most famous for their extraordinary mechanisms of monoallelic gene expression and antigenic variation, they have also been investigated because much of their biology is either highly unconventional or extreme. Moreover, in addition to their importance as pathogens, many researchers have been attracted to the field because trypanosomes have some of the most advanced molecular genetic tools and database resources of any model system. The following will cover just some aspects of trypanosome biology and how its divergent biochemistry has been leveraged to develop drugs to treat African sleeping sickness. This is by no means intended to be a comprehensive survey of trypanosome features. Rather, I hope to present trypanosomes as one of the most fascinating and tractable systems to do discovery biology.
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Affiliation(s)
- Samuel Dean
- Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
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23
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Reproduction in Trypanosomatids: Past and Present. BIOLOGY 2021; 10:biology10060471. [PMID: 34071741 PMCID: PMC8230138 DOI: 10.3390/biology10060471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 01/07/2023]
Abstract
Simple Summary The reproduction of trypanosomatids is a fundamental issue for host–parasite interaction, and its biological importance lies in knowing how these species acquire new defense mechanisms against the countermeasures imposed by the host, which is consistent with the theory of the endless race or the Red Queen hypothesis for the existence of meiotic sex. Moreover, the way these species re-produce may also be at the origin of novel and more virulent clades and is relevant from a thera-peutic or vaccination point of view, as sex may contribute to increased tolerance and even to the rapid acquisition of drug resistance mechanisms. Kinetoplastids are single-celled organisms, many of them being responsible for important parasitic diseases, globally termed neglected diseases, which are endemic in low-income countries. Leishmaniasis, African (sleeping sickness) and American trypanosomiasis (Chagas disease) caused by trypanosomatids are among the most ne-glected tropical scourges related to poverty and poor health systems. The reproduction of these microorganisms has long been considered to be clonal due to population genetic observations. However, there is increasing evidence of true sex and genetic exchange events under laboratory conditions. We would like to highlight the importance of this topic in the field of host/parasite in-terplay, virulence, and drug resistance. Abstract Diseases caused by trypanosomatids (Sleeping sickness, Chagas disease, and leishmaniasis) are a serious public health concern in low-income endemic countries. These diseases are produced by single-celled parasites with a diploid genome (although aneuploidy is frequent) organized in pairs of non-condensable chromosomes. To explain the way they reproduce through the analysis of natural populations, the theory of strict clonal propagation of these microorganisms was taken as a rule at the beginning of the studies, since it partially justified their genomic stability. However, numerous experimental works provide evidence of sexual reproduction, thus explaining certain naturally occurring events that link the number of meiosis per mitosis and the frequency of mating. Recent techniques have demonstrated genetic exchange between individuals of the same species under laboratory conditions, as well as the expression of meiosis specific genes. The current debate focuses on the frequency of genomic recombination events and its impact on the natural parasite population structure. This paper reviews the results and techniques used to demonstrate the existence of sex in trypanosomatids, the inheritance of kinetoplast DNA (maxi- and minicircles), the impact of genetic exchange in these parasites, and how it can contribute to the phenotypic diversity of natural populations.
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Peacock L, Kay C, Farren C, Bailey M, Carrington M, Gibson W. Sequential production of gametes during meiosis in trypanosomes. Commun Biol 2021; 4:555. [PMID: 33976359 PMCID: PMC8113336 DOI: 10.1038/s42003-021-02058-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 03/24/2021] [Indexed: 02/03/2023] Open
Abstract
Meiosis is a core feature of eukaryotes that occurs in all major groups, including the early diverging excavates. In this group, meiosis and production of haploid gametes have been described in the pathogenic protist, Trypanosoma brucei, and mating occurs in the salivary glands of the insect vector, the tsetse fly. Here, we searched for intermediate meiotic stages among trypanosomes from tsetse salivary glands. Many different cell types were recovered, including trypanosomes in Meiosis I and gametes. Significantly, we found trypanosomes containing three nuclei with a 1:2:1 ratio of DNA contents. Some of these cells were undergoing cytokinesis, yielding a mononucleate gamete and a binucleate cell with a nuclear DNA content ratio of 1:2. This cell subsequently produced three more gametes in two further rounds of division. Expression of the cell fusion protein HAP2 (GCS1) was not confined to gametes, but also extended to meiotic intermediates. We propose a model whereby the two nuclei resulting from Meiosis I undergo asynchronous Meiosis II divisions with sequential production of haploid gametes.
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Affiliation(s)
- Lori Peacock
- School of Biological Sciences University of Bristol, Bristol, UK
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Chris Kay
- School of Biological Sciences University of Bristol, Bristol, UK
| | - Chloe Farren
- School of Biological Sciences University of Bristol, Bristol, UK
| | - Mick Bailey
- Bristol Veterinary School, University of Bristol, Bristol, UK
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Wendy Gibson
- School of Biological Sciences University of Bristol, Bristol, UK.
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25
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Tromer EC, Wemyss TA, Ludzia P, Waller RF, Akiyoshi B. Repurposing of synaptonemal complex proteins for kinetochores in Kinetoplastida. Open Biol 2021; 11:210049. [PMID: 34006126 PMCID: PMC8131943 DOI: 10.1098/rsob.210049] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/16/2021] [Indexed: 12/25/2022] Open
Abstract
Chromosome segregation in eukaryotes is driven by the kinetochore, a macromolecular complex that connects centromeric DNA to microtubules of the spindle apparatus. Kinetochores in well-studied model eukaryotes consist of a core set of proteins that are broadly conserved among distant eukaryotic phyla. By contrast, unicellular flagellates of the class Kinetoplastida have a unique set of 36 kinetochore components. The evolutionary origin and history of these kinetochores remain unknown. Here, we report evidence of homology between axial element components of the synaptonemal complex and three kinetoplastid kinetochore proteins KKT16-18. The synaptonemal complex is a zipper-like structure that assembles between homologous chromosomes during meiosis to promote recombination. By using sensitive homology detection protocols, we identify divergent orthologues of KKT16-18 in most eukaryotic supergroups, including experimentally established chromosomal axis components, such as Red1 and Rec10 in budding and fission yeast, ASY3-4 in plants and SYCP2-3 in vertebrates. Furthermore, we found 12 recurrent duplications within this ancient eukaryotic SYCP2-3 gene family, providing opportunities for new functional complexes to arise, including KKT16-18 in the kinetoplastid parasite Trypanosoma brucei. We propose the kinetoplastid kinetochore system evolved by repurposing meiotic components of the chromosome synapsis and homologous recombination machinery that were already present in early eukaryotes.
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Affiliation(s)
- Eelco C. Tromer
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Cell Biochemistry, Groningen Institute of Biomolecular Sciences & Biotechnology, University of Groningen, Groningen, The Netherlands
| | - Thomas A. Wemyss
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Patryk Ludzia
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Bungo Akiyoshi
- Department of Biochemistry, University of Oxford, Oxford, UK
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26
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Gibson W. The sexual side of parasitic protists. Mol Biochem Parasitol 2021; 243:111371. [PMID: 33872659 DOI: 10.1016/j.molbiopara.2021.111371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/26/2021] [Accepted: 04/13/2021] [Indexed: 01/09/2023]
Abstract
Much of the vast evolutionary landscape occupied by Eukaryotes is dominated by protists. Though parasitism has arisen in many lineages, there are three main groups of parasitic protists of relevance to human and livestock health: the Apicomplexa, including the malaria parasite Plasmodium and coccidian pathogens of livestock such as Eimeria; the excavate flagellates, encompassing a diverse range of protist pathogens including trypanosomes, Leishmania, Giardia and Trichomonas; and the Amoebozoa, including pathogenic amoebae such as Entamoeba. These three groups represent separate, deep branches of the eukaryote tree, underlining their divergent evolutionary histories. Here, I explore what is known about sex in these three main groups of parasitic protists.
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Affiliation(s)
- Wendy Gibson
- School of Biological Sciences, Life Sciences Building, University of Bristol, Bristol, BS8 1TQ, United Kingdom.
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27
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Butenko A, Hammond M, Field MC, Ginger ML, Yurchenko V, Lukeš J. Reductionist Pathways for Parasitism in Euglenozoans? Expanded Datasets Provide New Insights. Trends Parasitol 2020; 37:100-116. [PMID: 33127331 DOI: 10.1016/j.pt.2020.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 12/21/2022]
Abstract
The unicellular trypanosomatids belong to the phylum Euglenozoa and all known species are obligate parasites. Distinct lineages infect plants, invertebrates, and vertebrates, including humans. Genome data for marine diplonemids, together with freshwater euglenids and free-living kinetoplastids, the closest known nonparasitic relatives to trypanosomatids, recently became available. Robust phylogenetic reconstructions across Euglenozoa are now possible and place the results of parasite-focused studies into an evolutionary context. Here we discuss recent advances in identifying the factors shaping the evolution of Euglenozoa, focusing on ancestral features generally considered parasite-specific. Remarkably, most of these predate the transition(s) to parasitism, suggesting that the presence of certain preconditions makes a significant lifestyle change more likely.
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Affiliation(s)
- Anzhelika Butenko
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Science, University of Ostrava, Ostrava, Czech Republic.
| | - Michael Hammond
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Mark C Field
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; School of Life Sciences, University of Dundee, Dundee, UK
| | - Michael L Ginger
- School of Applied Sciences, University of Huddersfield, Huddersfield, UK
| | - Vyacheslav Yurchenko
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic; Martsinovsky Institute of Medical Parasitology, Sechenov University, Moscow, Russia
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
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28
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Cotton JA, Franssen SU. A Way Straight-Forward for Leishmania Genetics. Trends Parasitol 2020; 36:719-721. [PMID: 32741600 DOI: 10.1016/j.pt.2020.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 11/29/2022]
Abstract
Genetic exchange between Leishmania parasites was demonstrated in sandflies over 10 years ago. Louradour et al. have shown in vitro hybridization of two Leishmania tropica isolates, with the potential to remove a major roadblock to using forward genetics in Leishmania, understanding Leishmania reproductive biology, and analyzing gene flow in natural populations.
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Affiliation(s)
- James A Cotton
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Susanne U Franssen
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK.
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29
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Cruz-Saavedra L, Vallejo GA, Guhl F, Ramírez JD. Transcriptomic changes across the life cycle of Trypanosoma cruzi II. PeerJ 2020; 8:e8947. [PMID: 32461822 PMCID: PMC7231504 DOI: 10.7717/peerj.8947] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/19/2020] [Indexed: 12/15/2022] Open
Abstract
Trypanosoma cruzi is a flagellated protozoan that causes Chagas disease; it presents a complex life cycle comprising four morphological stages: epimastigote (EP), metacyclic trypomastigote (MT), cell-derived trypomastigote (CDT) and amastigote (AM). Previous transcriptomic studies on three stages (EPs, CDTs and AMs) have demonstrated differences in gene expressions among them; however, to the best of our knowledge, no studies have reported on gene expressions in MTs. Therefore, the present study compared differentially expressed genes (DEGs), and signaling pathway reconstruction in EPs, MTs, AMs and CDTs. The results revealed differences in gene expressions in the stages evaluated; these differences were greater between MTs and AMs-PTs. The signaling pathway that presented the highest number of DEGs in all the stages was associated with ribosomes protein profiles, whereas the other related pathways activated were processes related to energy metabolism from glucose, amino acid metabolism, or RNA regulation. However, the role of autophagy in the entire life cycle of T. cruzi and the presence of processes such as meiosis and homologous recombination in MTs (where the expressions of SPO11 and Rad51 plays a role) are crucial. These findings represent an important step towards the full understanding of the molecular basis during the life cycle of T. cruzi.
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Affiliation(s)
- Lissa Cruz-Saavedra
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
| | - Gustavo A Vallejo
- Laboratorio de Investigación en Parasitología Tropical, Facultad de Ciencias, Universidad del Tolima, Ibagué, Colombia
| | - Felipe Guhl
- Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Facultad de Ciencias, Universidad de Los Andes, Bogota, Colombia
| | - Juan David Ramírez
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales, Universidad del Rosario, Bogota, Colombia
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Touching the Surface: Diverse Roles for the Flagellar Membrane in Kinetoplastid Parasites. Microbiol Mol Biol Rev 2020; 84:84/2/e00079-19. [PMID: 32238446 DOI: 10.1128/mmbr.00079-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
While flagella have been studied extensively as motility organelles, with a focus on internal structures such as the axoneme, more recent research has illuminated the roles of the flagellar surface in a variety of biological processes. Parasitic protists of the order Kinetoplastida, which include trypanosomes and Leishmania species, provide a paradigm for probing the role of flagella in host-microbe interactions and illustrate that this interface between the flagellar surface and the host is of paramount importance. An increasing body of knowledge indicates that the flagellar membrane serves a multitude of functions at this interface: attachment of parasites to tissues within insect vectors, close interactions with intracellular organelles of vertebrate cells, transactions between flagella from different parasites, junctions between the flagella and the parasite cell body, emergence of nanotubes and exosomes from the parasite directed to either host or microbial targets, immune evasion, and sensing of the extracellular milieu. Recent whole-organelle or genome-wide studies have begun to identify protein components of the flagellar surface that must mediate these diverse host-parasite interactions. The increasing corpus of knowledge on kinetoplastid flagella will likely prove illuminating for other flagellated or ciliated pathogens as well.
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31
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Cotton JA, Durrant C, Franssen SU, Gelanew T, Hailu A, Mateus D, Sanders MJ, Berriman M, Volf P, Miles MA, Yeo M. Genomic analysis of natural intra-specific hybrids among Ethiopian isolates of Leishmania donovani. PLoS Negl Trop Dis 2020; 14:e0007143. [PMID: 32310945 PMCID: PMC7237039 DOI: 10.1371/journal.pntd.0007143] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 05/19/2020] [Accepted: 12/24/2019] [Indexed: 12/30/2022] Open
Abstract
Parasites of the genus Leishmania (Kinetoplastida: Trypanosomatidae) cause widespread and devastating human diseases. Visceral leishmaniasis due to Leishmania donovani is endemic in Ethiopia where it has also been responsible for major epidemics. The presence of hybrid genotypes has been widely reported in surveys of natural populations, genetic variation reported in a number of Leishmania species, and the extant capacity for genetic exchange demonstrated in laboratory experiments. However, patterns of recombination and the evolutionary history of admixture that produced these hybrid populations remain unclear. Here, we use whole-genome sequence data to investigate Ethiopian L. donovani isolates previously characterized as hybrids by microsatellite and multi-locus sequencing. To date there is only one previous study on a natural population of Leishmania hybrids based on whole-genome sequences. We propose that these hybrids originate from recombination between two different lineages of Ethiopian L. donovani occurring in the same region. Patterns of inheritance are more complex than previously reported with multiple, apparently independent, origins from similar parents that include backcrossing with parental types. Analysis indicates that hybrids are representative of at least three different histories. Furthermore, isolates were highly polysomic at the level of chromosomes with differences between parasites recovered from a recrudescent infection from a previously treated individual. The results demonstrate that recombination is a significant feature of natural populations and contributes to the growing body of data that shows how recombination, and gene flow, shape natural populations of Leishmania.
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Affiliation(s)
| | | | | | - Tesfaye Gelanew
- Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
| | - Asrat Hailu
- Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
| | - David Mateus
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michael A. Miles
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matthew Yeo
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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32
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ImageJ for Partially and Fully Automated Analysis of Trypanosome Micrographs. Methods Mol Biol 2020. [PMID: 32221933 DOI: 10.1007/978-1-0716-0294-2_24] [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: 09/07/2023]
Abstract
Trypanosomes and related parasites such as Leishmania are unicellular parasites with a precise internal structure. This makes light microscopy a powerful tool for interrogating their biology-whether considering advance techniques for visualizing the precise localization of proteins within the cell or simply measuring parasite cell shape. Methods to partially or fully automate analysis and interpretation are extremely powerful and provide easier access to microscope images as a source of quantitative data. This chapter provides an introduction to these methods using ImageJ/FIJI, free and open source software for scientific image analysis. It provides an overview of how ImageJ handles images and introduces the ImageJ macro/scripting language for automated images, starting at a basic level and assuming no previous programming/scripting experience. It then outlines three methods using ImageJ for automated analysis of trypanosome micrographs: Semiautomated cropping and setting image contrast for presentation, automated analysis of cell properties from a light micrograph field of view, and example semiautomated tools for quantitative analysis of protein localization. These are not presented as strict methods, but are instead described in detail with the intention of furnishing the reader with the ability to "hack" the scripts for their own needs or write their own scripts for partially and fully automated quantitation of trypanosomes from light micrographs. Most of the methods described here are transferrable to other types of microscope image and other cell types.
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33
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Jansen AM, Xavier SCDC, Roque ALR. Landmarks of the Knowledge and Trypanosoma cruzi Biology in the Wild Environment. Front Cell Infect Microbiol 2020; 10:10. [PMID: 32117794 PMCID: PMC7016096 DOI: 10.3389/fcimb.2020.00010] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/10/2020] [Indexed: 12/13/2022] Open
Abstract
Trypanosomatids are ancient parasitic eukaryotes that still maintain prokaryotic characteristics. Trypanosoma cruzi, a primarily wild mammal parasite, infected humans already long before European colonization of the Americas. T. cruzi heterogeneity remains an unsolved question, and until now, it has still not been possible to associate T. cruzi genotypes with any biological or epidemiological feature. One of the first biochemical attempts to cluster the T. cruzi subpopulations recognized three main subpopulations (zymodemes) that have been associated with the transmission cycles in the wild (Z1; Z3) and in the domestic environment (Z2). The description of wild mammal species harboring Z2 two decades later challenged this assemblage attempt. Currently, the genotypes of T. cruzi are assembled in seven discrete typing units (DTUs). The biology of T. cruzi still shows novelties such as the description of epimastigotes multiplying and differentiating to metacyclic trypomastigotes in the lumen of the scent glands of Didelphis spp. and the capacity of the true meiosis in parallel to clonal reproduction. The study of the transmission cycle among wild animals has broken paradigms and raised new questions: (i) the interaction of the T. cruzi DTUs with each of its mammalian host species displays peculiarities; (ii) the impact of mixed genotypes and species on the transmissibility of one or another species or on pathogenesis is still unknown; (iii) independent T. cruzi transmission cycles may occur in the same forest fragment; (iv) the capacity to act as a reservoir depends on the peculiarities of the host species and the parasite genotype; and (v) faunistic composition is a defining trait of the T. cruzi transmission cycle profile. The development of models of environmental variables that determine the spatial distribution of the elements that make up T. cruzi transmission by spatial analysis, followed by map algebra and networking, are the next steps toward interpreting and dealing with the new profile of Chagas disease with its many peculiarities. There is no way to solve this neglected disease once and for all if not through a multidisciplinary look that takes into account all kinds of human and animal activities in parallel to environmental variations.
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Affiliation(s)
- Ana Maria Jansen
- Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
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34
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Rusman F, Floridia-Yapur N, Ragone PG, Diosque P, Tomasini N. Evidence of hybridization, mitochondrial introgression and biparental inheritance of the kDNA minicircles in Trypanosoma cruzi I. PLoS Negl Trop Dis 2020; 14:e0007770. [PMID: 32004318 PMCID: PMC7015434 DOI: 10.1371/journal.pntd.0007770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 02/12/2020] [Accepted: 01/13/2020] [Indexed: 11/21/2022] Open
Abstract
Background Genetic exchange in Trypanosoma cruzi is controversial not only in relation to its frequency, but also to its mechanism. Parasexual genetic exchange has been proposed based on laboratory hybrids, but population genomics strongly suggests meiosis in T. cruzi. In addition, mitochondrial introgression has been reported several times in natural isolates although its mechanism is not fully understood yet. Moreover, hybrid T. cruzi DTUs (TcV and TcVI) have inherited at least part of the kinetoplastic DNA (kDNA = mitochondrial DNA) from both parents. Methodology/Principal findings In order to address such topics, we sequenced and analyzed fourteen nuclear DNA fragments and three kDNA maxicircle genes in three TcI stocks which are natural clones potentially involved in events of genetic exchange. We also deep-sequenced (a total of 6,146,686 paired-end reads) the minicircle hypervariable region (mHVR) of the kDNA in such three strains. In addition, we analyzed the DNA content by flow cytometry to address cell ploidy. We observed that most polymorphic sites in nuclear loci showed a hybrid pattern in one cloned strain and the other two cloned strains were compatible as parental strains (or nearly related to the true parents). The three clones had almost the same ploidy and the DNA content was similar to the reference strain Sylvio (a nearly diploid strain). Despite maxicircle genes evolve faster than nuclear housekeeping ones, we detected no polymorphisms in the sequence of three maxicircle genes showing mito-nuclear discordance. Lastly, the hybrid stock shared 66% of its mHVR clusters with one putative parent and 47% with the other one; in contrast, the putative parental stocks shared less than 30% of the mHVR clusters between them. Conclusions/significance The results suggest a reductive division, a natural hybridization, biparental inheritance of the minicircles in the hybrid and maxicircle introgression. The models including such phenomena and explaining the relationships between these three clones are discussed. Chagas disease, an important public health problem in Latin America, is caused by the parasite Trypanosoma cruzi. Despite being a widely studied parasite, several questions on the biology of genetic exchange remain unanswered. Population genomic studies have inferred meiosis in T. cruzi, but this cellular division mechanism has not been observed in laboratory yet. In addition, previous results suggest that mitochondrial DNA (called kDNA) may be inherited from both parents in hybrids. Here, we analyzed a hybrid strain and its potential parents to address the mechanisms of genetic exchange at nuclear and mitochondrial levels. We observed that the hybrid strain had heterozygous patterns and DNA content compatible with a meiosis event. Also, we observed that the evolutionary histories of nuclear DNA and kDNA maxicircles were discordant and that the three strains shared identical DNA sequences. Mitochondrial introgression of maxicircle DNA from one genotype to another may explain this observation. In addition, we demonstrated that the hybrid strain shared kDNA minicircles with both parental strains. Our results suggest that hybridization implied meiosis and biparental inheritance of the kDNA. Further research is required to address such phenomena in detail.
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Affiliation(s)
- Fanny Rusman
- Unidad de Epidemiología Molecular (UEM), Instituto de Patología Experimental, Universidad Nacional de Salta-CONICET, Salta, Salta, Argentina
| | - Noelia Floridia-Yapur
- Unidad de Epidemiología Molecular (UEM), Instituto de Patología Experimental, Universidad Nacional de Salta-CONICET, Salta, Salta, Argentina
| | - Paula G. Ragone
- Unidad de Epidemiología Molecular (UEM), Instituto de Patología Experimental, Universidad Nacional de Salta-CONICET, Salta, Salta, Argentina
| | - Patricio Diosque
- Unidad de Epidemiología Molecular (UEM), Instituto de Patología Experimental, Universidad Nacional de Salta-CONICET, Salta, Salta, Argentina
| | - Nicolás Tomasini
- Unidad de Epidemiología Molecular (UEM), Instituto de Patología Experimental, Universidad Nacional de Salta-CONICET, Salta, Salta, Argentina
- * E-mail:
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Maciver SK. Ancestral Eukaryotes Reproduced Asexually, Facilitated by Polyploidy: A Hypothesis. Bioessays 2019; 41:e1900152. [DOI: 10.1002/bies.201900152] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/10/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Sutherland K. Maciver
- Centre for Discovery Brain Sciences, Edinburgh Medical SchoolBiomedical SciencesUniversity of Edinburgh Hugh Robson Building, George Square Edinburgh EH8 9XD Scotland UK
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36
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Abstract
Trypanosomes have complex life cycles within which there are both proliferative and differentiation cell divisions. The coordination of the cell cycle to achieve these different divisions is critical for the parasite to infect both host and vector. From studying the regulation of the proliferative cell cycle of the Trypanosoma brucei procyclic life cycle stage, three subcycles emerge that control the duplication and segregation of ( a) the nucleus, ( b) the kinetoplast, and ( c) a set of cytoskeletal structures. We discuss how the clear dependency relationships within these subcycles, and the potential for cross talk between them, are likely required for overall cell cycle coordination. Finally, we look at the implications this interdependence has for proliferative and differentiation divisions through the T. brucei life cycle and in related parasitic trypanosomatid species.
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Affiliation(s)
- Richard J. Wheeler
- Nuffield Department of Medicine, University of Oxford, Oxford OX1 3SY, United Kingdom
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Jack D. Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
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Schwabl P, Imamura H, Van den Broeck F, Costales JA, Maiguashca-Sánchez J, Miles MA, Andersson B, Grijalva MJ, Llewellyn MS. Meiotic sex in Chagas disease parasite Trypanosoma cruzi. Nat Commun 2019; 10:3972. [PMID: 31481692 PMCID: PMC6722143 DOI: 10.1038/s41467-019-11771-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 07/27/2019] [Indexed: 12/11/2022] Open
Abstract
Genetic exchange enables parasites to rapidly transform disease phenotypes and exploit new host populations. Trypanosoma cruzi, the parasitic agent of Chagas disease and a public health concern throughout Latin America, has for decades been presumed to exchange genetic material rarely and without classic meiotic sex. We present compelling evidence from 45 genomes sequenced from southern Ecuador that T. cruzi in fact maintains truly sexual, panmictic groups that can occur alongside others that remain highly clonal after past hybridization events. These groups with divergent reproductive strategies appear genetically isolated despite possible co-occurrence in vectors and hosts. We propose biological explanations for the fine-scale disconnectivity we observe and discuss the epidemiological consequences of flexible reproductive modes. Our study reinvigorates the hunt for the site of genetic exchange in the T. cruzi life cycle, provides tools to define the genetic determinants of parasite virulence, and reforms longstanding theory on clonality in trypanosomatid parasites.
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Affiliation(s)
- Philipp Schwabl
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Hideo Imamura
- Unit of Molecular Parasitology, Institute of Tropical Medicine Antwerp, 155 Nationalestraat, 2000, Antwerp, Belgium
| | - Frederik Van den Broeck
- Unit of Molecular Parasitology, Institute of Tropical Medicine Antwerp, 155 Nationalestraat, 2000, Antwerp, Belgium
| | - Jaime A Costales
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
| | - Jalil Maiguashca-Sánchez
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
| | - Michael A Miles
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Bjorn Andersson
- Department of Cell and Molecular Biology, Science for Life Laboratory, Karolinska Institutet, Biomedicum 9C, 171 77, Stockholm, Sweden
| | - Mario J Grijalva
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
- Infectious and Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, 45701, Athens, OH, USA
| | - Martin S Llewellyn
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
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38
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Berry ASF, Salazar-Sánchez R, Castillo-Neyra R, Borrini-Mayorí K, Chipana-Ramos C, Vargas-Maquera M, Ancca-Juarez J, Náquira-Velarde C, Levy MZ, Brisson D. Sexual reproduction in a natural Trypanosoma cruzi population. PLoS Negl Trop Dis 2019; 13:e0007392. [PMID: 31107905 PMCID: PMC6544315 DOI: 10.1371/journal.pntd.0007392] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 05/31/2019] [Accepted: 04/15/2019] [Indexed: 12/21/2022] Open
Abstract
Background Sexual reproduction provides an evolutionary advantageous mechanism that combines favorable mutations that have arisen in separate lineages into the same individual. This advantage is especially pronounced in microparasites as allelic reassortment among individuals caused by sexual reproduction promotes allelic diversity at immune evasion genes within individuals which is often essential to evade host immune systems. Despite these advantages, many eukaryotic microparasites exhibit highly-clonal population structures suggesting that genetic exchange through sexual reproduction is rare. Evidence supporting clonality is particularly convincing in the causative agent of Chagas disease, Trypanosoma cruzi, despite equally convincing evidence of the capacity to engage in sexual reproduction. Methodology/ Principle Findings In the present study, we investigated two hypotheses that can reconcile the apparent contradiction between the observed clonal population structure and the capacity to engage in sexual reproduction by analyzing the genome sequences of 123 T. cruzi isolates from a natural population in Arequipa, Peru. The distribution of polymorphic markers within and among isolates provides clear evidence of the occurrence of sexual reproduction. Large genetic segments are rearranged among chromosomes due to crossing over during meiosis leading to a decay in the genetic linkage among polymorphic markers compared to the expectations from a purely asexually-reproducing population. Nevertheless, the population structure appears clonal due to a high level of inbreeding during sexual reproduction which increases homozygosity, and thus reduces diversity, within each inbreeding lineage. Conclusions/ Significance These results effectively reconcile the apparent contradiction by demonstrating that the clonal population structure is derived not from infrequent sex in natural populations but from high levels of inbreeding. We discuss epidemiological consequences of this reproductive strategy on genome evolution, population structure, and phenotypic diversity of this medically important parasite. The rearrangement of alleles among individuals in a population during sexual reproduction maintains high allelic diversity within individuals in a population at polymorphic genes. Allelic diversity within individuals can be particularly important for parasites as it enhances their ability to evade host immune systems. Despite the potential benefits of sexual reproduction for parasites, natural populations of the protozoan parasite—and causative agent of human Chagas disease—Trypanosoma cruzi, exhibit clonal population structures indicative of asexual reproduction. This is particularly surprising as T. cruzi has the capacity for sexual reproduction. Here, we resolve this apparent contradiction by sequencing whole genomes of 123 T. cruzi isolates from a natural population in Arequipa, Peru. Evidence of past sexual reproduction and allelic rearrangements are common in this T. cruzi population. However, the majority of sexual reproduction events occur between close relatives resulting in an apparent clonal population structure. Sexual reproduction with distant relatives in areas with greater strain diversity has the potential to affect public health by increasing diversity in immune evasion genes within individuals and enhancing within-host survival, rapidly diversifying antigens that could affect the sensitivity of serological diagnostics, and by generating diversity in pathogenicity or drug resistance.
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Affiliation(s)
- Alexander S. F. Berry
- Division of Gastroenterology, Hepatology, and Nutrition, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Renzo Salazar-Sánchez
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
| | - Ricardo Castillo-Neyra
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
- Department of Biostatistics, Epidemiology and Informatics, The Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Katty Borrini-Mayorí
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
| | - Claudia Chipana-Ramos
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
| | - Melina Vargas-Maquera
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
| | - Jenny Ancca-Juarez
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
| | - César Náquira-Velarde
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
| | - Michael Z. Levy
- Universidad Peruana Cayetano Heredia/University of Pennsylvania Chagas Disease Field Laboratory, Arequipa, Peru
- Department of Biostatistics, Epidemiology and Informatics, The Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Dustin Brisson
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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39
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Inbar E, Shaik J, Iantorno SA, Romano A, Nzelu CO, Owens K, Sanders MJ, Dobson D, Cotton JA, Grigg ME, Beverley SM, Sacks D. Whole genome sequencing of experimental hybrids supports meiosis-like sexual recombination in Leishmania. PLoS Genet 2019; 15:e1008042. [PMID: 31091230 PMCID: PMC6519804 DOI: 10.1371/journal.pgen.1008042] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 02/21/2019] [Indexed: 11/29/2022] Open
Abstract
Hybrid genotypes have been repeatedly described among natural isolates of Leishmania, and the recovery of experimental hybrids from sand flies co-infected with different strains or species of Leishmania has formally demonstrated that members of the genus possess the machinery for genetic exchange. As neither gamete stages nor cell fusion events have been directly observed during parasite development in the vector, we have relied on a classical genetic analysis to determine if Leishmania has a true sexual cycle. Here, we used whole genome sequencing to follow the chromosomal inheritance patterns of experimental hybrids generated within and between different strains of L. major and L. infantum. We also generated and sequenced the first experimental hybrids in L. tropica. We found that in each case the parental somy and allele contributions matched the inheritance patterns expected under meiosis 97–99% of the time. The hybrids were equivalent to F1 progeny, heterozygous throughout most of the genome for the markers that were homozygous and different between the parents. Rare, non-Mendelian patterns of chromosomal inheritance were observed, including a gain or loss of somy, and loss of heterozygosity, that likely arose during meiosis or during mitotic divisions of the progeny clones in the fly or culture. While the interspecies hybrids appeared to be sterile, the intraspecies hybrids were able to produce backcross and outcross progeny. Analysis of 5 backcross and outcross progeny clones generated from an L. major F1 hybrid, as well as 17 progeny clones generated from backcrosses involving a natural hybrid of L. tropica, revealed genome wide patterns of recombination, demonstrating that classical crossing over occurs at meiosis, and allowed us to construct the first physical and genetic maps in Leishmania. Altogether, the findings provide strong evidence for meiosis-like sexual recombination in Leishmania, presenting clear opportunities for forward genetic analysis and positional cloning of important genes. Leishmania promastigotes are able to undergo genetic exchange during their growth and development in the sand fly vector, however, it is still not known if they have a true sexual cycle involving meiosis. Here, we used whole genome sequencing to follow the chromosomal inheritance patterns of 44 experimental hybrids generated between different strains of L. major, L. infantum, and L. tropica. In almost every case the number of chromosomes and the allele contributions from each parent matched the inheritance patterns expected under meiosis. Rare instances of hybrid chromosomes that did not fit Mendelian expectations were observed, including gain or loss of somy, and loss of heterozygosity. Strong evidence for a meiotic-like process was also obtained from the genome wide patterns of recombination observed in the offspring generated from backcrosses involving an experimental or natural hybrid, consistent with crossing over occurring between homologous chromosomes during meiosis. The frequency and position of the recombination breakpoints observed on each chromosome allowed us to construct the first physical and genetic maps in Leishmania. The results demonstrate that forward genetic approaches are possible for positional cloning of important genes.
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Affiliation(s)
- Ehud Inbar
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jahangheer Shaik
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Molecular Microbiology, Washington University School of Medicine in St Louis, St Louis, Missouri, United States of America
| | - Stefano A. Iantorno
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Audrey Romano
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Chukwunonso O. Nzelu
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Katherine Owens
- Department of Molecular Microbiology, Washington University School of Medicine in St Louis, St Louis, Missouri, United States of America
| | - Mandy J. Sanders
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Deborah Dobson
- Department of Molecular Microbiology, Washington University School of Medicine in St Louis, St Louis, Missouri, United States of America
| | - James A. Cotton
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Michael E. Grigg
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stephen M. Beverley
- Department of Molecular Microbiology, Washington University School of Medicine in St Louis, St Louis, Missouri, United States of America
| | - David Sacks
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: ,
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40
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Espinosa A, Paz-Y-Miño-C G. Discrimination Experiments in Entamoeba and Evidence from Other Protists Suggest Pathogenic Amebas Cooperate with Kin to Colonize Hosts and Deter Rivals. J Eukaryot Microbiol 2019; 66:354-368. [PMID: 30055104 PMCID: PMC6349510 DOI: 10.1111/jeu.12673] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/27/2018] [Accepted: 07/25/2018] [Indexed: 01/06/2023]
Abstract
Entamoeba histolytica is one of the least understood protists in terms of taxa, clone, and kin discrimination/recognition ability. However, the capacity to tell apart same or self (clone/kin) from different or nonself (nonclone/nonkin) has long been demonstrated in pathogenic eukaryotes like Trypanosoma and Plasmodium, free-living social amebas (Dictyostelium, Polysphondylium), budding yeast (Saccharomyces), and in numerous bacteria and archaea (prokaryotes). Kin discrimination/recognition is explained under inclusive fitness theory; that is, the reproductive advantage that genetically closely related organisms (kin) can gain by cooperating preferably with one another (rather than with distantly related or unrelated individuals), minimizing antagonism and competition with kin, and excluding genetic strangers (or cheaters = noncooperators that benefit from others' investments in altruistic cooperation). In this review, we rely on the outcomes of in vitro pairwise discrimination/recognition encounters between seven Entamoeba lineages to discuss the biological significance of taxa, clone, and kin discrimination/recognition in a range of generalist and specialist species (close or distantly related phylogenetically). We then focus our discussion on the importance of these laboratory observations for E. histolytica's life cycle, host infestation, and implications of these features of the amebas' natural history for human health (including mitigation of amebiasis).
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Affiliation(s)
- Avelina Espinosa
- Department of Biology, Roger Williams University, Bristol, Rhode Island
- New England Center for the Public Understanding of Science, Roger Williams University, Bristol, Rhode Island
| | - Guillermo Paz-Y-Miño-C
- New England Center for the Public Understanding of Science, Roger Williams University, Bristol, Rhode Island
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41
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Gibson W, Peacock L. Fluorescent proteins reveal what trypanosomes get up to inside the tsetse fly. Parasit Vectors 2019; 12:6. [PMID: 30609932 PMCID: PMC6320599 DOI: 10.1186/s13071-018-3204-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 11/19/2018] [Indexed: 12/12/2022] Open
Abstract
The discovery and development of fluorescent proteins for the investigation of living cells and whole organisms has been a major advance in biomedical research. This approach was quickly exploited by parasitologists, particularly those studying single-celled protists. Here we describe some of our experiments to illustrate how fluorescent proteins have helped to reveal what trypanosomes get up to inside the tsetse fly. Fluorescent proteins turned the tsetse fly from a “black box” into a bright showcase to track trypanosome migration and development within the insect. Crosses of genetically modified red and green fluorescent trypanosomes produced yellow fluorescent hybrids and established the “when” and “where” of trypanosome sexual reproduction inside the fly. Fluorescent-tagging endogenous proteins enabled us to identify the meiotic division stage and gametes inside the salivary glands of the fly and thus elucidate the mechanism of sexual reproduction in trypanosomes. Without fluorescent proteins we would still be in the “dark ages” of understanding what trypanosomes get up to inside the tsetse fly.
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Affiliation(s)
- Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
| | - Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.,School of Clinical Veterinary Science, University of Bristol, Langford, Bristol, BS40 7DU, UK
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42
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Krüger T, Schuster S, Engstler M. Beyond Blood: African Trypanosomes on the Move. Trends Parasitol 2018; 34:1056-1067. [DOI: 10.1016/j.pt.2018.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/07/2023]
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43
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Reis-Cunha JL, Baptista RP, Rodrigues-Luiz GF, Coqueiro-Dos-Santos A, Valdivia HO, de Almeida LV, Cardoso MS, D'Ávila DA, Dias FHC, Fujiwara RT, Galvão LMC, Chiari E, Cerqueira GC, Bartholomeu DC. Whole genome sequencing of Trypanosoma cruzi field isolates reveals extensive genomic variability and complex aneuploidy patterns within TcII DTU. BMC Genomics 2018; 19:816. [PMID: 30424726 PMCID: PMC6234542 DOI: 10.1186/s12864-018-5198-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 10/23/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trypanosoma cruzi, the etiologic agent of Chagas disease, is currently divided into six discrete typing units (DTUs), named TcI-TcVI. TcII is among the major DTUs enrolled in human infections in South America southern cone, where it is associated with severe cardiac and digestive symptoms. Despite the importance of TcII in Chagas disease epidemiology and pathology, so far, no genome-wide comparisons of the mitochondrial and nuclear genomes of TcII field isolates have been performed to track the variability and evolution of this DTU in endemic regions. RESULTS In the present work, we have sequenced and compared the whole nuclear and mitochondrial genomes of seven TcII strains isolated from chagasic patients from the central and northeastern regions of Minas Gerais, Brazil, revealing an extensive genetic variability within this DTU. A comparison of the phylogeny based on the nuclear or mitochondrial genomes revealed that the majority of branches were shared by both sequences. The subtle divergences in the branches are probably consequence of mitochondrial introgression events between TcII strains. Two T. cruzi strains isolated from patients living in the central region of Minas Gerais, S15 and S162a, were clustered in the nuclear and mitochondrial phylogeny analysis. These two strains were isolated from the other five by the Espinhaço Mountains, a geographic barrier that could have restricted the traffic of insect vectors during T. cruzi evolution in the Minas Gerais state. Finally, the presence of aneuploidies was evaluated, revealing that all seven TcII strains have a different pattern of chromosomal duplication/loss. CONCLUSIONS Analysis of genomic variability and aneuploidies suggests that there is significant genomic variability within Minas Gerais TcII strains, which could be exploited by the parasite to allow rapid selection of favorable phenotypes. Also, the aneuploidy patterns vary among T. cruzi strains and does not correlate with the nuclear phylogeny, suggesting that chromosomal duplication/loss are recent and frequent events in the parasite evolution.
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Affiliation(s)
- João Luís Reis-Cunha
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo P Baptista
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,The University of Georgia, Athens, USA
| | - Gabriela F Rodrigues-Luiz
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | | | - Hugo O Valdivia
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,U.S. Naval Medical Research, Lima, Peru
| | - Laila Viana de Almeida
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mariana Santos Cardoso
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | | | | | - Lúcia M C Galvão
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Egler Chiari
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | - Daniella C Bartholomeu
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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44
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Alves CL, Repolês BM, da Silva MS, Mendes IC, Marin PA, Aguiar PHN, Santos SDS, Franco GR, Macedo AM, Pena SDJ, Andrade LDO, Guarneri AA, Tahara EB, Elias MC, Machado CR. The recombinase Rad51 plays a key role in events of genetic exchange in Trypanosoma cruzi. Sci Rep 2018; 8:13335. [PMID: 30190603 PMCID: PMC6127316 DOI: 10.1038/s41598-018-31541-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 08/16/2018] [Indexed: 12/11/2022] Open
Abstract
Detection of genetic exchange has been a limiting factor to deepen the knowledge on the mechanisms by which Trypanosoma cruzi is able to generate progeny and genetic diversity. Here we show that incorporation of halogenated thymidine analogues, followed by immunostaining, is a reliable method not only to detect T. cruzi fused-cell hybrids, but also to quantify their percentage in populations of this parasite. Through this approach, we were able to detect and quantify fused-cell hybrids of T. cruzi clones CL Brener and Y. Given the increased detection of fused-cell hybrids in naturally-occurring hybrid CL Brener strain, which displays increased levels of RAD51 and BRCA2 transcripts, we further investigated the role of Rad51 - a recombinase involved in homologous recombination - in the process of genetic exchange. We also verified that the detection of fused-cell hybrids in T. cruzi overexpressing RAD51 is increased when compared to wild-type cells, suggesting a key role for Rad51 either in the formation or in the stabilization of fused-cell hybrids in this organism.
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Affiliation(s)
- Ceres Luciana Alves
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Bruno Marçal Repolês
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Marcelo Santos da Silva
- Laboratório Especial de Ciclo Celular, Centro de Toxinas, Resposta Imune e Sinalização Celular, Instituto Butantan, São Paulo, SP, Brazil
| | - Isabela Cecília Mendes
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Paula Andrea Marin
- Laboratório Especial de Ciclo Celular, Centro de Toxinas, Resposta Imune e Sinalização Celular, Instituto Butantan, São Paulo, SP, Brazil
| | | | - Selma da Silva Santos
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Glória Regina Franco
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Andréa Mara Macedo
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Sérgio Danilo Junho Pena
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | | | - Erich Birelli Tahara
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Centro de Toxinas, Resposta Imune e Sinalização Celular, Instituto Butantan, São Paulo, SP, Brazil
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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Krishnan D, Ghosh SK. Cellular Events of Multinucleated Giant Cells Formation During the Encystation of Entamoeba invadens. Front Cell Infect Microbiol 2018; 8:262. [PMID: 30109218 PMCID: PMC6079502 DOI: 10.3389/fcimb.2018.00262] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/13/2018] [Indexed: 12/21/2022] Open
Abstract
Entamoeba histolytica, the causative agent of amoebiasis, does not form cysts in vitro, so reptilian pathogen Entamoeba invadens is used as an Entamoeba encystation model. During the in vitro encystation of E. invadens, a few multinucleated giant cells (MGC) were also appeared in the culture along with cysts. Like the cyst, these MGC's were also formed in the multicellular aggregates found in the encystation culture. Time-lapse live cell imaging revealed that MGC's were the result of repeated cellular fusion with fusion-competent trophozoites as a starting point. The early MGC were non-adherent, and they moved slowly and randomly in the media, but under confinement, MGC became highly motile and directionally persistent. The increased motility resulted in rapid cytoplasmic fissions, which indicated the possibility of continuous cell fusion and division taking place inside the compact multicellular aggregates. Following cell fusion, each nucleus obtained from the fusion-competent trophozoites gave rise to four nuclei with half genomic content. All the haploid nuclei in MGC later aggregated and fused to form a polyploid nucleus. These observations have important implications on Entamoeba biology as they point toward the possibility of E. invadens undergoing sexual or parasexual reproduction.
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Affiliation(s)
- Deepak Krishnan
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Sudip K Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
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Recent advances in trypanosomatid research: genome organization, expression, metabolism, taxonomy and evolution. Parasitology 2018; 146:1-27. [PMID: 29898792 DOI: 10.1017/s0031182018000951] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Unicellular flagellates of the family Trypanosomatidae are obligatory parasites of invertebrates, vertebrates and plants. Dixenous species are aetiological agents of a number of diseases in humans, domestic animals and plants. Their monoxenous relatives are restricted to insects. Because of the high biological diversity, adaptability to dramatically different environmental conditions, and omnipresence, these protists have major impact on all biotic communities that still needs to be fully elucidated. In addition, as these organisms represent a highly divergent evolutionary lineage, they are strikingly different from the common 'model system' eukaryotes, such as some mammals, plants or fungi. A number of excellent reviews, published over the past decade, were dedicated to specialized topics from the areas of trypanosomatid molecular and cell biology, biochemistry, host-parasite relationships or other aspects of these fascinating organisms. However, there is a need for a more comprehensive review that summarizing recent advances in the studies of trypanosomatids in the last 30 years, a task, which we tried to accomplish with the current paper.
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Krafsur ES, Maudlin I. Tsetse fly evolution, genetics and the trypanosomiases - A review. INFECTION GENETICS AND EVOLUTION 2018; 64:185-206. [PMID: 29885477 DOI: 10.1016/j.meegid.2018.05.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 01/27/2023]
Abstract
This reviews work published since 2007. Relative efforts devoted to the agents of African trypanosomiasis and their tsetse fly vectors are given by the numbers of PubMed accessions. In the last 10 years PubMed citations number 3457 for Trypanosoma brucei and 769 for Glossina. The development of simple sequence repeats and single nucleotide polymorphisms afford much higher resolution of Glossina and Trypanosoma population structures than heretofore. Even greater resolution is offered by partial and whole genome sequencing. Reproduction in T. brucei sensu lato is principally clonal although genetic recombination in tsetse salivary glands has been demonstrated in T. b. brucei and T. b. rhodesiense but not in T. b. gambiense. In the past decade most genetic attention was given to the chief human African trypanosomiasis vectors in subgenus Nemorhina e.g., Glossina f. fuscipes, G. p. palpalis, and G. p. gambiense. The chief interest in Nemorhina population genetics seemed to be finding vector populations sufficiently isolated to enable efficient and long-lasting suppression. To this end estimates were made of gene flow, derived from FST and its analogues, and Ne, the size of a hypothetical population equivalent to that under study. Genetic drift was greater, gene flow and Ne typically lesser in savannah inhabiting tsetse (subgenus Glossina) than in riverine forms (Nemorhina). Population stabilities were examined by sequential sampling and genotypic analysis of nuclear and mitochondrial genomes in both groups and found to be stable. Gene frequencies estimated in sequential samplings differed by drift and allowed estimates of effective population numbers that were greater for Nemorhina spp than Glossina spp. Prospects are examined of genetic methods of vector control. The tsetse long generation time (c. 50 d) is a major contraindication to any suggested genetic method of tsetse population manipulation. Ecological and modelling research convincingly show that conventional methods of targeted insecticide applications and traps/targets can achieve cost-effective reduction in tsetse densities.
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Affiliation(s)
- E S Krafsur
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Ian Maudlin
- School of Biomedical Sciences, The University of Edinburgh, Scotland, UK
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Cestari I, Stuart K. Transcriptional Regulation of Telomeric Expression Sites and Antigenic Variation in Trypanosomes. Curr Genomics 2018; 19:119-132. [PMID: 29491740 PMCID: PMC5814960 DOI: 10.2174/1389202918666170911161831] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/03/2017] [Accepted: 05/04/2017] [Indexed: 12/29/2022] Open
Abstract
INTRODUCTION Trypanosoma brucei uses antigenic variation to evade the host antibody clearance by periodically changing its Variant Surface Glycoprotein (VSGs) coat. T. brucei encode over 2,500 VSG genes and pseudogenes, however they transcribe only one VSG gene at time from one of the 20 telomeric Expression Sites (ESs). VSGs are transcribed in a monoallelic fashion by RNA polymerase I from an extranucleolar site named ES body. VSG antigenic switching occurs by transcriptional switching between telomeric ESs or by recombination of the VSG gene expressed. VSG expression is developmentally regulated and its transcription is controlled by epigenetic mechanisms and influenced by a telomere position effect. CONCLUSION Here, we discuss 1) the molecular basis underlying transcription of telomeric ESs and VSG antigenic switching; 2) the current knowledge of VSG monoallelic expression; 3) the role of inositol phosphate pathway in the regulation of VSG expression and switching; and 4) the developmental regulation of Pol I transcription of procyclin and VSG genes.
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Affiliation(s)
- Igor Cestari
- Center for Infectious Disease Research, Seattle, WA98109, USA
| | - Ken Stuart
- Center for Infectious Disease Research, Seattle, WA98109, USA
- Department of Global Health, University of Washington, Seattle, WA98195, USA
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Bernstein H, Bernstein C, Michod RE. Sex in microbial pathogens. INFECTION GENETICS AND EVOLUTION 2018; 57:8-25. [DOI: 10.1016/j.meegid.2017.10.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 10/25/2017] [Accepted: 10/26/2017] [Indexed: 10/18/2022]
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Tihon E, Imamura H, Dujardin JC, Van Den Abbeele J. Evidence for viable and stable triploid Trypanosoma congolense parasites. Parasit Vectors 2017; 10:468. [PMID: 29017575 PMCID: PMC5635536 DOI: 10.1186/s13071-017-2406-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/26/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Recent whole genome sequencing (WGS) analysis identified a viable triploid strain of Trypanosoma congolense. This triploid strain BANANCL2 was a clone of the field isolate BANAN/83/CRTRA/64 that was collected from cattle in Burkina Faso in 1983. RESULTS We demonstrated the viability and stability of triploidy throughout the complete life-cycle of the parasite by infecting tsetse flies with the triploid clone BANANCL2. Proboscis-positive tsetse flies efficiently transmitted the parasites to mice resulting in systemic infections. WGS of the parasites was performed at all life-cycle stages, and a method based on a block alternative allele frequency spectrum was developed to efficiently detect the ploidy profiles of samples with low read depth. This approach confirmed the triploid profile of parasites throughout their life-cycle in the tsetse fly and the mammalian host, demonstrating that triploidy is present at all stages and is stable over time. CONCLUSION The presence of viable field-isolated triploid parasites indicates another possible layer of genetic diversity in natural T. congolense populations. The comparison between triploid and diploid parasites provides a unique model system to study the impact of chromosome copy number variations in African trypanosomes. In addition, the consequences of triploidy can be further investigated using this stable triploid model.
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Affiliation(s)
- Eliane Tihon
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium
| | - Hideo Imamura
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium
| | - Jean-Claude Dujardin
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium
| | - Jan Van Den Abbeele
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium.
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