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Seatamanoch N, Kongdachalert S, Sunantaraporn S, Siriyasatien P, Brownell N. Microsporidia, a Highly Adaptive Organism and Its Host Expansion to Humans. Front Cell Infect Microbiol 2022; 12:924007. [PMID: 35782144 PMCID: PMC9245026 DOI: 10.3389/fcimb.2022.924007] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/23/2022] [Indexed: 12/05/2022] Open
Abstract
Emerging infectious disease has become the center of attention since the outbreak of COVID-19. For the coronavirus, bats are suspected to be the origin of the pandemic. Consequently, the spotlight has fallen on zoonotic diseases, and the focus now expands to organisms other than viruses. Microsporidia is a single-cell organism that can infect a wide range of hosts such as insects, mammals, and humans. Its pathogenicity differs among species, and host immunological status plays an important role in infectivity and disease severity. Disseminated disease from microsporidiosis can be fatal, especially among patients with a defective immune system. Recently, there were two Trachipleistophora hominis, a microsporidia species which can survive in insects, case reports in Thailand, one patient had disseminated microsporidiosis. This review gathered data of disseminated microsporidiosis and T. hominis infections in humans covering the biological and clinical aspects. There was a total of 22 cases of disseminated microsporidiosis reports worldwide. Ten microsporidia species were identified. Maximum likelihood tree results showed some possible correlations with zoonotic transmissions. For T. hominis, there are currently eight case reports in humans, seven of which had Human Immunodeficiency Virus (HIV) infection. It is observed that risks are higher for the immunocompromised to acquire such infections, however, future studies should look into the entire life cycle, to identify the route of transmission and establish preventive measures, especially among the high-risk groups.
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Affiliation(s)
- Nirin Seatamanoch
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Switt Kongdachalert
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Sakone Sunantaraporn
- Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Padet Siriyasatien
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Narisa Brownell
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- *Correspondence: Narisa Brownell,
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Abstract
Microsporidia are obligate intracellular pathogens identified ∼150 years ago as the cause of pébrine, an economically important infection in silkworms. There are about 220 genera and 1,700 species of microsporidia, which are classified based on their ultrastructural features, developmental cycle, host-parasite relationship, and molecular analysis. Phylogenetic analysis suggests that microsporidia are related to the fungi, being grouped with the Cryptomycota as a basal branch or sister group to the fungi. Microsporidia can be transmitted by food and water and are likely zoonotic, as they parasitize a wide range of invertebrate and vertebrate hosts. Infection in humans occurs in both immunocompetent and immunodeficient hosts, e.g., in patients with organ transplantation, patients with advanced human immunodeficiency virus (HIV) infection, and patients receiving immune modulatory therapy such as anti-tumor necrosis factor alpha antibody. Clusters of infections due to latent infection in transplanted organs have also been demonstrated. Gastrointestinal infection is the most common manifestation; however, microsporidia can infect virtually any organ system, and infection has resulted in keratitis, myositis, cholecystitis, sinusitis, and encephalitis. Both albendazole and fumagillin have efficacy for the treatment of various species of microsporidia; however, albendazole has limited efficacy for the treatment of Enterocytozoon bieneusi. In addition, immune restoration can lead to resolution of infection. While the prevalence rate of microsporidiosis in patients with AIDS has fallen in the United States, due to the widespread use of combination antiretroviral therapy (cART), infection continues to occur throughout the world and is still seen in the United States in the setting of cART if a low CD4 count persists.
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Major P, Sendra KM, Dean P, Williams TA, Watson AK, Thwaites DT, Embley TM, Hirt RP. A new family of cell surface located purine transporters in Microsporidia and related fungal endoparasites. eLife 2019; 8:47037. [PMID: 31355745 PMCID: PMC6699826 DOI: 10.7554/elife.47037] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/23/2019] [Indexed: 01/20/2023] Open
Abstract
Plasma membrane-located transport proteins are key adaptations for obligate intracellular Microsporidia parasites, because they can use them to steal host metabolites the parasites need to grow and replicate. However, despite their importance, the functions and substrate specificities of most Microsporidia transporters are unknown. Here, we provide functional data for a family of transporters conserved in all microsporidian genomes and also in the genomes of related endoparasites. The universal retention among otherwise highly reduced genomes indicates an important role for these transporters for intracellular parasites. Using Trachipleistophora hominis, a Microsporidia isolated from an HIV/AIDS patient, as our experimental model, we show that the proteins are ATP and GTP transporters located on the surface of parasites during their intracellular growth and replication. Our work identifies a new route for the acquisition of essential energy and nucleotides for a major group of intracellular parasites that infect most animal species including humans. Microsporidia are a group of microscopic parasites that spend part of their lives inside the cells of a broad range of animal hosts, including humans. These parasites are considered to be related to fungi, some of which also live within the cells of other species and are known as fungal endoparasites. One of the shared characteristics of these parasites is that they cannot make nucleotides, molecules that are both the main source of energy of the cell and also the building blocks of DNA. Instead, they take nucleotides, or the materials needed to make nucleotides, from their host cells. Once Microsporidia have depleted a host cell, they turn into spores that can survive outside the host until they invade a new cell, starting the cycle anew. Microsporidia have proteins on their surface, including nucleotide transporter family proteins (NTT), that enable them to import nucleotides from their host into themselves. Although most fungal endoparasites are also thought to steal nucleotides from their hosts, many do not have NTT proteins, raising the question of how they import the nucleotides. A group of proteins called the Major Facilitator Superfamily (MFS) consists of proteins that were thought to transport the materials cells need to make nucleotides (which are also called nucleotide precursors). Members of this family are found throughout Microsporidia and related fungal endoparasites. These proteins could explain how fungal endoparasites take nucleotides from their hosts. To test this hypothesis, Major et al. infected mammalian cells with Microsporidia and then checked where two MFS proteins were located during infection. This showed that the proteins were on the surface of the endoparasites, implying that they could be nucleotide precursor transporters. Next, Major et al. genetically modified Escherichia coli bacteria so they would produce MFS proteins, and showed that the proteins could transport two types of nucleotides. Together these results show that MFS proteins could be responsible for nucleotide transport in fungal endoparasites. In addition to humans, Microsporidia and related fungal endoparasites infect a wide range of animals, including pollinating insects, which have ecological and economic importance. Given that Microsporidia can only survive if they take nucleotides from their hosts, knowing more about the proteins that import the nucleotides could lead to new cures for Microsporidia infections.
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Affiliation(s)
- Peter Major
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kacper M Sendra
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Paul Dean
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tom A Williams
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew K Watson
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David T Thwaites
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert P Hirt
- Institute for Cell and Molecular Biosciences, the Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom
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Wijayawardene NN, Pawłowska J, Letcher PM, Kirk PM, Humber RA, Schüßler A, Wrzosek M, Muszewska A, Okrasińska A, Istel Ł, Gęsiorska A, Mungai P, Lateef AA, Rajeshkumar KC, Singh RV, Radek R, Walther G, Wagner L, Walker C, Wijesundara DSA, Papizadeh M, Dolatabadi S, Shenoy BD, Tokarev YS, Lumyong S, Hyde KD. Notes for genera: basal clades of Fungi (including Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Calcarisporiellomycota, Caulochytriomycota, Chytridiomycota, Entomophthoromycota, Glomeromycota, Kickxellomycota, Monoblepharomycota, Mortierellomycota, Mucoromycota, Neocallimastigomycota, Olpidiomycota, Rozellomycota and Zoopagomycota). FUNGAL DIVERS 2018. [DOI: 10.1007/s13225-018-0409-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Ferguson S, Lucocq J. The invasive cell coat at the microsporidian Trachipleistophora hominis-host cell interface contains secreted hexokinases. Microbiologyopen 2018; 8:e00696. [PMID: 30051624 PMCID: PMC6460350 DOI: 10.1002/mbo3.696] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/22/2018] [Accepted: 06/25/2018] [Indexed: 02/04/2023] Open
Abstract
Microsporidia are obligate intracellular parasites causing significant disease in humans and economically important animals. In parallel to their extreme genetic reduction, Microsporidia have evolved novel mechanisms for exploiting host metabolism. A number of microsporidians confer secretion of otherwise cytosolic proteins by coding for signal peptides that direct entry into the endoplasmic reticulum. The human pathogen Trachipleistophora hominis encodes for four hexokinases, three of which have signal peptides at the N‐terminus. Here, we localized hexokinase 2 and hexokinase 3 through developmental stages of T. hominis using light and electron microscopy. Both proteins were concentrated in an extracellular coat previously termed the plaque matrix (PQM). The PQM (containing hexokinases) was morphologically dynamic, infiltrating the host cytoplasm predominantly during replicative stages. Throughout development the PQM interacted closely with endoplasmic reticulum that was demonstrated to be active in membrane protein biosynthesis and export. The impact of hexokinase on the host metabolism was probed using the fluorescent analog of glucose, 2‐NBDG, which displayed spatially restricted increases in signal intensity at the parasite/vacuole surface, coincident with hexokinase/PQM distribution. Gross metabolic aberrations, measured using metabolic profiling with the Seahorse XF Analyzer, were not detectable in mixed stage cocultures. Overall, these results highlight a role for the extended cell coat of T. hominis in host–parasite interactions, within which secreted hexokinases may work as part of a metabolic machine to increase glycolytic capacity or ATP generation close to the parasite surface.
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Affiliation(s)
- Sophie Ferguson
- Structural Cell Biology Group, School of Medicine, University of St Andrews, St Andrews, UK
| | - John Lucocq
- Structural Cell Biology Group, School of Medicine, University of St Andrews, St Andrews, UK
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Discovery of a novel microsporidium in laboratory colonies of Mediterranean cricket Gryllus bimaculatus (Orthoptera: Gryllidae): Microsporidium grylli sp. nov. Parasitol Res 2018; 117:2823-2829. [DOI: 10.1007/s00436-018-5970-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/13/2018] [Indexed: 10/28/2022]
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Freibert SA, Goldberg AV, Hacker C, Molik S, Dean P, Williams TA, Nakjang S, Long S, Sendra K, Bill E, Heinz E, Hirt RP, Lucocq JM, Embley TM, Lill R. Evolutionary conservation and in vitro reconstitution of microsporidian iron-sulfur cluster biosynthesis. Nat Commun 2017; 8:13932. [PMID: 28051091 PMCID: PMC5216125 DOI: 10.1038/ncomms13932] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/14/2016] [Indexed: 12/22/2022] Open
Abstract
Microsporidians are obligate intracellular parasites that have minimized their genome content and sub-cellular structures by reductive evolution. Here, we demonstrate that cristae-deficient mitochondria (mitosomes) of Trachipleistophora hominis are the functional site of iron–sulfur cluster (ISC) assembly, which we suggest is the essential task of these organelles. Cell fractionation, fluorescence imaging and immunoelectron microscopy demonstrate that mitosomes contain a complete pathway for [2Fe–2S] cluster biosynthesis that we biochemically reconstituted using purified mitosomal ISC proteins. The T. hominis cytosolic iron–sulfur protein assembly (CIA) pathway includes the essential Cfd1–Nbp35 scaffold complex that assembles a [4Fe–4S] cluster as shown by spectroscopic methods in vitro. Phylogenetic analyses reveal that the ISC and CIA pathways are predominantly bacterial, but their cytosolic and nuclear target Fe/S proteins are mainly archaeal. This mixed evolutionary history of Fe/S-related proteins and pathways, and their strong conservation among highly reduced parasites, provides compelling evidence for the ancient chimeric ancestry of eukaryotes.
The functions of the highly reduced mitochondria (mitosomes) of microsporidians are not well-characterized. Here, the authors show that the Trachipleistophora hominis mitosome is the site of iron–sulfur cluster assembly and that its retention is likely linked to its role in cytosolic and nuclear iron–sulfur protein maturation.
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Affiliation(s)
- Sven-A Freibert
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität, Robert-Koch-Strasse 6, Marburg 35032, Germany
| | - Alina V Goldberg
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Christian Hacker
- School of Medicine, University of St Andrews, St. Andrews KY16 9TF, UK.,Bioimaging Centre, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Sabine Molik
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität, Robert-Koch-Strasse 6, Marburg 35032, Germany
| | - Paul Dean
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Tom A Williams
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Sirintra Nakjang
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Shaojun Long
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Kacper Sendra
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Eckhard Bill
- Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, Mülheim an der Ruhr 45470, Germany
| | - Eva Heinz
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Robert P Hirt
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - John M Lucocq
- School of Medicine, University of St Andrews, St. Andrews KY16 9TF, UK
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK
| | - Roland Lill
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität, Robert-Koch-Strasse 6, Marburg 35032, Germany.,LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, Hans-Meerwein-Strasse, Marburg 35043, Germany
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Weber R. Intestinal Coccidia and Microsporidia. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00192-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Williams TA, Nakjang S, Campbell SE, Freeman MA, Eydal M, Moore K, Hirt RP, Embley TM, Williams BAP. A Recent Whole-Genome Duplication Divides Populations of a Globally Distributed Microsporidian. Mol Biol Evol 2016; 33:2002-15. [PMID: 27189558 PMCID: PMC4948709 DOI: 10.1093/molbev/msw083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Microsporidia are a major group of intracellular fungi and important parasites of animals including insects, fish, and immunocompromised humans. Microsporidian genomes have undergone extreme reductive evolution but there are major differences in genome size and structure within the group: some are prokaryote-like in size and organisation (<3 Mb of gene-dense sequence) while others have more typically eukaryotic genome architectures. To gain fine-scale, population-level insight into the evolutionary dynamics of these tiny eukaryotic genomes, we performed the broadest microsporidian population genomic study to date, sequencing geographically isolated strains of Spraguea, a marine microsporidian infecting goosefish worldwide. Our analysis revealed that population structure across the Atlantic Ocean is associated with a conserved difference in ploidy, with American and Canadian isolates sharing an ancestral whole genome duplication that was followed by widespread pseudogenisation and sorting-out of paralogue pairs. While past analyses have suggested de novo gene formation of microsporidian-specific genes, we found evidence for the origin of new genes from noncoding sequence since the divergence of these populations. Some of these genes experience selective constraint, suggesting the evolution of new functions and local host adaptation. Combining our data with published microsporidian genomes, we show that nucleotide composition across the phylum is shaped by a mutational bias favoring A and T nucleotides, which is opposed by an evolutionary force favoring an increase in genomic GC content. This study reveals ongoing dramatic reorganization of genome structure and the evolution of new gene functions in modern microsporidians despite extensive genomic streamlining in their common ancestor.
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Affiliation(s)
- Tom A Williams
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Sirintra Nakjang
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Scott E Campbell
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, United Kingdom
| | - Mark A Freeman
- Ross University School of Veterinary Medicine, St. Kitts, West Indies
| | - Matthías Eydal
- Institute for Experimental Pathology, University of Iceland, Keldur, Iceland
| | - Karen Moore
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, United Kingdom
| | - Robert P Hirt
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bryony A P Williams
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, United Kingdom
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Watson AK, Williams TA, Williams BAP, Moore KA, Hirt RP, Embley TM. Transcriptomic profiling of host-parasite interactions in the microsporidian Trachipleistophora hominis. BMC Genomics 2015; 16:983. [PMID: 26589282 PMCID: PMC4654818 DOI: 10.1186/s12864-015-1989-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 10/06/2015] [Indexed: 12/28/2022] Open
Abstract
Background Trachipleistophora hominis was isolated from an HIV/AIDS patient and is a member of a highly successful group of obligate intracellular parasites. Methods Here we have investigated the evolution of the parasite and the interplay between host and parasite gene expression using transcriptomics of T. hominis-infected rabbit kidney cells. Results T. hominis has about 30 % more genes than small-genome microsporidians. Highly expressed genes include those involved in growth, replication, defence against oxidative stress, and a large fraction of uncharacterised genes. Chaperones are also highly expressed and may buffer the deleterious effects of the large number of non-synonymous mutations observed in essential T. hominis genes. Host expression suggests a general cellular shutdown upon infection, but ATP, amino sugar and nucleotide sugar production appear enhanced, potentially providing the parasite with substrates it cannot make itself. Expression divergence of duplicated genes, including transporters used to acquire host metabolites, demonstrates ongoing functional diversification during microsporidian evolution. We identified overlapping transcription at more than 100 loci in the sparse T. hominis genome, demonstrating that this feature is not caused by genome compaction. The detection of additional transposons of insect origin strongly suggests that the natural host for T. hominis is an insect. Conclusions Our results reveal that the evolution of contemporary microsporidian genomes is highly dynamic and innovative. Moreover, highly expressed T. hominis genes of unknown function include a cohort that are shared among all microsporidians, indicating that some strongly conserved features of the biology of these enormously successful parasites remain uncharacterised. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1989-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrew K Watson
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
| | - Tom A Williams
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
| | - Bryony A P Williams
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, UK.
| | - Karen A Moore
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Devon, UK.
| | - Robert P Hirt
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
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Plasma membrane-located purine nucleotide transport proteins are key components for host exploitation by microsporidian intracellular parasites. PLoS Pathog 2014; 10:e1004547. [PMID: 25474405 PMCID: PMC4256464 DOI: 10.1371/journal.ppat.1004547] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/31/2014] [Indexed: 12/31/2022] Open
Abstract
Microsporidia are obligate intracellular parasites of most animal groups including humans, but despite their significant economic and medical importance there are major gaps in our understanding of how they exploit infected host cells. We have investigated the evolution, cellular locations and substrate specificities of a family of nucleotide transport (NTT) proteins from Trachipleistophora hominis, a microsporidian isolated from an HIV/AIDS patient. Transport proteins are critical to microsporidian success because they compensate for the dramatic loss of metabolic pathways that is a hallmark of the group. Our data demonstrate that the use of plasma membrane-located nucleotide transport proteins (NTT) is a key strategy adopted by microsporidians to exploit host cells. Acquisition of an ancestral transporter gene at the base of the microsporidian radiation was followed by lineage-specific events of gene duplication, which in the case of T. hominis has generated four paralogous NTT transporters. All four T. hominis NTT proteins are located predominantly to the plasma membrane of replicating intracellular cells where they can mediate transport at the host-parasite interface. In contrast to published data for Encephalitozoon cuniculi, we found no evidence for the location for any of the T. hominis NTT transporters to its minimal mitochondria (mitosomes), consistent with lineage-specific differences in transporter and mitosome evolution. All of the T. hominis NTTs transported radiolabelled purine nucleotides (ATP, ADP, GTP and GDP) when expressed in Escherichia coli, but did not transport radiolabelled pyrimidine nucleotides. Genome analysis suggests that imported purine nucleotides could be used by T. hominis to make all of the critical purine-based building-blocks for DNA and RNA biosynthesis during parasite intracellular replication, as well as providing essential energy for parasite cellular metabolism and protein synthesis. Microsporidians are highly reduced obligate intracellular eukaryotic parasites that cause significant disease in humans, animals and commercially relevant insects. Despite their medical and economic interest the mechanisms whereby microsporidians exploit the cells they infect are mainly unknown. We have characterised a conserved family of nucleotide transport proteins that we demonstrate have key roles in parasite biology. Microsporidians cannot synthesize the primary building blocks needed to make DNA and RNA for themselves, so they must import the starting materials from the infected host. We show that the microsporidian Trachipleistophora hominis, originally isolated from an HIV/AIDS patient, may achieve this by using four nucleotide transport proteins located in the plasma membrane of replicating intracellular parasites. In functional assays we demonstrate that all four proteins can transport radiolabelled adenine and guanine nucleotides. Genome analysis suggests that the imported nucleotides could be transformed by T. hominis into all of the critical purine-based building-blocks needed for DNA and RNA biosynthesis during parasite intracellular replication, as well as providing essential energy for parasite cellular metabolism and protein synthesis.
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Hacker C, Howell M, Bhella D, Lucocq J. Strategies for maximizing ATP supply in the microsporidian Encephalitozoon cuniculi: direct binding of mitochondria to the parasitophorous vacuole and clustering of the mitochondrial porin VDAC. Cell Microbiol 2013; 16:565-79. [PMID: 24245785 PMCID: PMC4233961 DOI: 10.1111/cmi.12240] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/11/2013] [Accepted: 11/11/2013] [Indexed: 11/29/2022]
Abstract
Microsporidia are obligate intracellular parasites with extremely reduced genomes and a dependence on host-derived ATP. The microsporidium Encephalitozoon cuniculi proliferates within a membranous vacuole and we investigated how the ATP supply is optimized at the vacuole-host interface. Using spatial EM quantification (stereology), we found a single layer of mitochondria coating substantial proportions of the parasitophorous vacuole. Mitochondrial binding occurred preferentially over the vegetative 'meront' stages of the parasite, which bulged into the cytoplasm, thereby increasing the membrane surface available for mitochondrial interaction. In a broken cell system mitochondrial binding was maintained and was typified by electron dense structures (< 10 nm long) bridging between outer mitochondrial and vacuole membranes. In broken cells mitochondrial binding was sensitive to a range of protease treatments. The function of directly bound mitochondria, as measured by the membrane potential sensitive dye JC-1, was indistinguishable from other mitochondria in the cell although there was a generalized depression of the membrane potential in infected cells. Finally, quantitative immuno-EM revealed that the ATP-delivering mitochondrial porin, VDAC, was concentrated atthe mitochondria-vacuole interaction site. Thus E. cuniculi appears to maximize ATP supply by direct binding of mitochondria to the parasitophorous vacuole bringing this organelle within 0.020 microns of the growing vegetative form of the parasite. ATP-delivery is further enhanced by clustering of ATP transporting porins in those regions of the outer mitochondrial membrane lying closest to the parasite.
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Affiliation(s)
- Christian Hacker
- School of Medicine, University of St Andrews, North Haugh, St Andrews, Fife, KF16 9TF, UK
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The genome of the obligate intracellular parasite Trachipleistophora hominis: new insights into microsporidian genome dynamics and reductive evolution. PLoS Pathog 2012; 8:e1002979. [PMID: 23133373 PMCID: PMC3486916 DOI: 10.1371/journal.ppat.1002979] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 09/05/2012] [Indexed: 11/30/2022] Open
Abstract
The dynamics of reductive genome evolution for eukaryotes living inside other eukaryotic cells are poorly understood compared to well-studied model systems involving obligate intracellular bacteria. Here we present 8.5 Mb of sequence from the genome of the microsporidian Trachipleistophora hominis, isolated from an HIV/AIDS patient, which is an outgroup to the smaller compacted-genome species that primarily inform ideas of evolutionary mode for these enormously successful obligate intracellular parasites. Our data provide detailed information on the gene content, genome architecture and intergenic regions of a larger microsporidian genome, while comparative analyses allowed us to infer genomic features and metabolism of the common ancestor of the species investigated. Gene length reduction and massive loss of metabolic capacity in the common ancestor was accompanied by the evolution of novel microsporidian-specific protein families, whose conservation among microsporidians, against a background of reductive evolution, suggests they may have important functions in their parasitic lifestyle. The ancestor had already lost many metabolic pathways but retained glycolysis and the pentose phosphate pathway to provide cytosolic ATP and reduced coenzymes, and it had a minimal mitochondrion (mitosome) making Fe-S clusters but not ATP. It possessed bacterial-like nucleotide transport proteins as a key innovation for stealing host-generated ATP, the machinery for RNAi, key elements of the early secretory pathway, canonical eukaryotic as well as microsporidian-specific regulatory elements, a diversity of repetitive and transposable elements, and relatively low average gene density. Microsporidian genome evolution thus appears to have proceeded in at least two major steps: an ancestral remodelling of the proteome upon transition to intracellular parasitism that involved reduction but also selective expansion, followed by a secondary compaction of genome architecture in some, but not all, lineages. Microsporidians are enormously successful obligate intracellular parasites of animals, including humans. Despite their economic and medical importance, there are major gaps in our understanding of how microsporidians have made the transition from a free-living organism to one that can only complete its life cycle by living inside another cell. We present the larger genome of Trachipleistophora hominis isolated from a human patient with HIV/AIDS. Our analyses provide insights into the gene content, genome architecture and intergenic regions of a known opportunistic pathogen, and will facilitate the development of T. hominis as a much-needed model species that can also be grown in co-culture. The genome of T. hominis has more genes than other microsporidians, it has diverse regulatory motifs, and it contains a variety of transposable elements coupled with the machinery for RNA interference, which may eventually allow experimental down-regulation of T. hominis genes. Comparison of the genome of T. hominis with other microsporidians allowed us to infer properties of their common ancestor. Our analyses predict an ancestral microsporidian that was already an intracellular parasite with a reduced core proteome but one with a relatively large genome populated with diverse repetitive elements and a complex transcriptional regulatory network.
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Suankratay C, Thiansukhon E, Nilaratanakul V, Putaporntip C, Jongwutiwes S. Disseminated infection caused by novel species of Microsporidium, Thailand. Emerg Infect Dis 2012; 18:302-4. [PMID: 22305387 PMCID: PMC3310463 DOI: 10.3201/eid1802.111319] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We describe a case of microsporidial myositis in a healthy man from Thailand. The small subunit rRNA sequence of this microsporidium is novel and has a close phylogenetic relationship with Endoreticulatus, a genus of lepidopteran microsporidia. Myositis could be caused by more genera of microsporidia than previously known.
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Opportunistic nature of the mammalian microsporidia: experimental transmission of Trachipleistophora extenrec (Fungi: Microsporidia) between mammalian and insect hosts. Parasitol Res 2010; 108:1565-73. [DOI: 10.1007/s00436-010-2213-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
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16
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Weber R. Protozoa. Infect Dis (Lond) 2010. [DOI: 10.1016/b978-0-323-04579-7.00181-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Vávra J, Horák A, Modrý D, Lukes J, Koudela B. Trachipleistophora extenrec n. sp. a new microsporidian (fungi: microsporidia) infecting mammals. J Eukaryot Microbiol 2008; 53:464-76. [PMID: 17123410 DOI: 10.1111/j.1550-7408.2006.00139.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new microsporidian Trachipleistophora extenrec n. sp. was isolated from a muscle lesion of the streaked tenrec Hemicentetes semispinosus Cuvier, 1798 (Mammalia, Tenrecidae), an insectivore endemic to Madagascar. The spores isolated from the tenrec were infectious to severe combined immunodeficient (SCID) mice by intramuscular injection. Material obtained from muscular lesions in mice was used for the parasite description. All developmental stages of the microsporidian were covered by a dense coat, which during sporogony changed into the sporophorous vesicle wall. Eight, 16, 32, or more spores were formed inside the sporophorous vesicle as the result of the division by plasmotomy and sequential fission of a multinucleate sporogonial plasmodium. Spores were ovoid, 4.7 x 2.8 microm in size, had a large posterior vacuole, and had an isofilar polar tube with 15-16 coils. Although the fine structure and the developmental pattern of the organism were in some respects similar to the genus Vavraia, molecular phylogeny based on the gene sequences of the small subunit rRNA and RNA polymerase subunit II indicated that the organism belongs to the genus Trachipleistophora. The diagnostic characters of the genera Trachipleistophora and Vavraia are discussed as well as the discrepancies between the phylogenies of these two microsporidian genera based on morphology and molecules.
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Affiliation(s)
- Jirí Vávra
- Institute of Parasitology, Biological Centre of the Czech Academy of Sciences, Ceské Budejovice, Czech Republic
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Vávra J, Becnel JJ. Vavraia culicis (Weiser, 1947) Weiser, 1977 revisited: cytological characterisation of a Vavraia culicis-like microsporidium isolated from mosquitoes in Florida and the establishment of Vavraia culicis floridensis subsp. n. Folia Parasitol (Praha) 2007. [DOI: 10.14411/fp.2007.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Didier ES, Maddry JA, Brindley PJ, Stovall ME, Didier PJ. Therapeutic strategies for human microsporidia infections. Expert Rev Anti Infect Ther 2007; 3:419-34. [PMID: 15954858 DOI: 10.1586/14787210.3.3.419] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Over the past 20 years, microsporidia have emerged as a cause of infectious diseases in AIDS patients, organ transplant recipients, children, travelers, contact lens wearers and the elderly. Enterocytozoon bieneusi and the Encephalitozoon spp., Encephalitozoon cuniculi, Encephalitozoon hellem and Encephalitozoon intestinalis, are the most frequently identified microsporidia in humans, and are associated with diarrhea and systemic disease. The microsporidia are small, single-celled, obligately intracellular parasites that have been identified in water sources, as well as in wild, domestic and food-producing farm animals, thereby raising concerns for waterborne, foodborne and zoonotic transmission. Current therapies for microsporidiosis include albendazole, a benzimidazole that inhibits microtubule assembly and is effective against several microsporidia, including the Encephalitozoon spp., although it is less effective against Encephalitozoon bieneusi. Fumagillin, an antibiotic and antiangiogenic compound produced by Aspergillus fumigatus, is more broadly effective against Encephalitozoon spp. and E. bieneusi; however, is toxic when administered systemically to mammals. Recent studies are also focusing on compounds that target the microsporidia polyamines (e.g., polyamine analogs), methionine aminopeptidase 2 (e.g., fumagillin-related compounds), chitin inhibitors (e.g., nikkomycins), topoisomerases (e.g., fluoroquinolones) and tubulin (e.g., benzimidazole-related compounds).
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Affiliation(s)
- Elizabeth S Didier
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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Becnel JJ. Expanding frontiers for microsporidia: a tribute to Professor Elizabeth U. Canning. J Invertebr Pathol 2006; 92:116-24. [PMID: 16764884 DOI: 10.1016/j.jip.2006.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 01/16/2006] [Indexed: 11/15/2022]
Affiliation(s)
- James J Becnel
- Center for Medical, Agricultural and Veterinary Entomology, USDA/ARS, 1600 SW 23rd Drive, Gainesville, FL 32608, USA.
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Juarez SI, Putaporntip C, Jongwutiwes S, Ichinose A, Yanagi T, Kanbara H. In vitro cultivation and electron microscopy characterization of Trachipleistophora anthropophthera isolated from the cornea of an AIDS patient. J Eukaryot Microbiol 2005; 52:179-90. [PMID: 15926993 DOI: 10.1111/j.1550-7408.2005.00024.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe an in vitro culture technique for a microsporidian isolated from the corneal biopsy of an HIV-infected patient. The corneal biopsy was inoculated into a monolayer culture of fibroblasts derived from newborn mouse brain and incubated at 37 degrees C in an atmosphere of 5% CO2. Minimum essential medium supplemented with 2% fetal bovine serum appeared to be an optimum medium for growth and maintenance of the parasite and for production of large numbers of spores. This microsporidian was identified as Trachipleistophora anthropophthera based on ultrastructural features. It forms two types of sporophorous vesicles and two types of spores simultaneously: polysporous vesicle type I with eight or more oval spores, 3.7-4.0 microm by 2.0-2.3 microm, and bisporous vesicle type II with two round spores, 1.7-2.2 microm by 1.6-2.0 microm in size.
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Affiliation(s)
- Sandra I Juarez
- Department of Protozoology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
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Matos E, Mendonça I, Azevedo C. Vavraia lutzomyiae n. sp. (Phylum Microspora) infecting the sandfly Lutzomyia longipalpis (Psychodidae, Phlebotominae), a vector of human visceral leishmaniasis. Eur J Protistol 2005; 42:21-8. [PMID: 17070748 DOI: 10.1016/j.ejop.2005.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Revised: 09/08/2005] [Accepted: 09/10/2005] [Indexed: 10/25/2022]
Abstract
Vavraia lutzomyiae (Microsporida; Pleistophoridae) is a new species parasitic in the tropical phlebotomine sandfly, Lutzomyia longipalpis (Diptera, Psychodidae, Phlebotominae), a major vector of Leishmania chagasi in Latin America where human visceral leishmaniasis is endemic. Infected larvae and pupae were parasitized in the abdomen, and some adults were parasitized in Malpighian tubules and midgut. The sporogonial plasmodium divided by multiple divisions into up to 64 uninucleate sporoblasts. These stages were surrounded outside the plasmalemma by a thick, amorphous dense coat and transformed into a merontogenetic sporophorous vesicle within which the sporonts developed into sporoblasts. The mature microsporidian spores were broadly ellipsoidal and measured 6.1+/-0.43 x 3.1+/-0.15 microm. The spore wall consisted of a transparent endospore (approximately 100 nm) and a thin electron dense exospore (approximately 30 nm) with the outer limit slightly undulated. Spores contained a polar filament arranged peripherally in a single layer of eight to nine wide anterior coils (approximately 125 nm diameter), and three to four narrow posterior coils (approximately 70 nm diameter). Transverse sections revealed a concentric layer organization with the internal layer surrounded by numerous (up to 25) longitudinal microfibrils. The angle of tilt of the polar filament was about 65-68 degrees.
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Affiliation(s)
- Edilson Matos
- Carlos Azevedo Research Laboratory, Federal Rural University of Amazonia, Belém, Pará, Brazil
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Cali A, Weiss LM, Takvorian PM. A review of the development of two types of human skeletal muscle infections from microsporidia associated with pathology in invertebrates and cold-blooded vertebrates. Folia Parasitol (Praha) 2005; 52:51-61. [PMID: 16004364 PMCID: PMC3109649 DOI: 10.14411/fp.2005.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Traditionally, the Microsporidia were primarily studied in insects and fish. There were only a few human cases of microsporidiosis reported until the advent of AIDS, when the number of human microsporidian infections dramatically increased and the importance of these new pathogens to medicine became evident. Over a dozen different kinds of microsporidia infecting humans have been reported. While some of these infections were identified in new genera (Enterocytozoon, Vittaforma), there were also infections identified from established genera such as Pleistophora and Encephalitozoon. The genus Pleistophora, originally erected for a species described from fish muscle, and the genus Encephalitozoon, originally described from disseminated infection in rabbits, suggested a link between human infections and animals. In the 1980's, three Pleistophora sp. infections were described from human skeletal muscle without life cycles presented. Subsequently, the genus Trachipleistophora was established for a human-infecting microsporidium with developmental differences from species of the genus Pleistophora. Thus, the existence of a true Pleistophora sp. or spp. in humans was put into question. We have demonstrated the life-cycle stages of the original Pleistophora sp. infection from human muscle, confirming the existence of a true Pleistophora species in humans, P. ronneafiei Cali et Takvorian, 2003, the first demonstrated in a mammalian host. Another human infection, caused by a parasite from invertebrates, was Brachiola algerae Lowman, Takvorian et Cali, 2000. The developmental stages of this human muscle-infecting microsporidium demonstrate morphologically what we have also confirmed by molecular means, that B. algerae, the mosquito parasite, is the causative agent of this human skeletal muscle infection. B. algerae had previously been demonstrated in humans but only in surface infections, skin and eye. The diagnostic features of B. algerae and P. ronneafiei infections in human skeletal muscle are presented. While Encephalitozoon cuniculi has been known as both an animal (mammal) and human parasite, the idea of human microsporidial infections derived from cold-blooded vertebrates and invertebrates has only been suggested by microsporidian phylogeny based on small subunit ribosomal DNA sequences but has not been appreciated. The morphological data presented here demonstrate these relationships. Additionally, water, as a link that connects microsporidial spores in the environment to potential host organisms, is diagrammatically presented.
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Affiliation(s)
- Ann Cali
- Department of Biologic Sciences, Rutgers University, Newark, New Jersey 07102, USA.
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Xu Y, Weiss LM. The microsporidian polar tube: a highly specialised invasion organelle. Int J Parasitol 2005; 35:941-53. [PMID: 16005007 PMCID: PMC3109658 DOI: 10.1016/j.ijpara.2005.04.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 03/28/2005] [Accepted: 04/05/2005] [Indexed: 11/30/2022]
Abstract
All of the members of the Microsporidia possess a unique, highly specialised structure, the polar tube. This article reviews the available data on the organisation, structure and function of this invasion organelle. It was over 100 years ago that Thelohan accurately described the microsporidian polar tube and the triggering of its discharge. In the spore, the polar tube is connected at the anterior end, and then coils around the sporoplasm. Upon appropriate environmental stimulation the polar tube rapidly discharges out of the spore pierces a cell membrane and serves as a conduit for sporoplasm passage into the new host cell. The mechanism of germination of spores, however, remains to be definitively determined. In addition, further studies on the characterisation of the early events in the rupture of the anterior attachment complex, eversion of the polar tube as well as the mechanism of host cell attachment and penetration are needed in order to clarify the function and assembly of this structure. The application of immunological and molecular techniques has resulted in the identification of three polar tube proteins referred to as PTP1, PTP2 and PTP3. The interactions of these identified proteins in the formation and function of the polar tube remain to be determined. Data suggest that PTP1 is an O-mannosylated glycoprotein, a post-translational modification that may be important for its function. With the availability of the Encephalitozoon cuniculi genome it is now possible to apply proteomic techniques to the characterisation of the components of the microsporidian spore and invasion organelle.
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Affiliation(s)
- Yanji Xu
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Medicine, Albert Einstein College of Medicine, Room 504 Forchheimer Building, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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25
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Abstract
Microsporidia are long-known parasitic organisms of almost every animal group, including invertebrates and vertebrates. Microsporidia emerged as important opportunistic pathogens in humans when AIDS became pandemic and, more recently, have also increasingly been detected in otherwise immunocompromised patients, including organ transplant recipients, and in immunocompetent persons with corneal infection or diarrhea. Two species causing rare infections in humans, Encephalitozoon cuniculi and Brachiola vesicularum, had previously been described from animal hosts (vertebrates and insects, respectively). However, several new microsporidial species, including Enterocytozoon bieneusi, the most prevalent human microsporidian causing human immunodeficiency virus-associated diarrhea, have been discovered in humans, raising the question of their natural origin. Vertebrate hosts are now identified for all four major microsporidial species infecting humans (E. bieneusi and the three Encephalitozoon spp.), implying a zoonotic nature of these parasites. Molecular studies have identified phenotypic and/or genetic variability within these species, indicating that they are not uniform, and have allowed the question of their zoonotic potential to be addressed. The focus of this review is the zoonotic potential of the various microsporidia and a brief update on other microsporidia which have no known host or an invertebrate host and which cause rare infections in humans.
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Affiliation(s)
- Alexander Mathis
- Institute of Parasitology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
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26
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Abstract
Microsporidia have emerged as causes of infectious diseases in AIDS patients, organ transplant recipients, children, travelers, contact lens wearers, and the elderly. These organisms are small single-celled, obligate intracellular parasites that were considered to be early eukaryotic protozoa but were recently reclassified with the fungi. Of the 14 species of microsporidia currently known to infect humans, Enterocytozoon bieneusi and Encephalitozoon intestinalis are the most common causes of human infections and are associated with diarrhea and systemic disease. Species of microsporidia infecting humans have been identified in water sources as well as in wild, domestic, and food-producing farm animals, raising concerns for waterborne, foodborne, and zoonotic transmission. Current therapies for microsporidiosis include albendazole which is a benzimidazole that inhibits microtubule assembly and is effective against several microsporidia, including the Encephalitozoon species, but is less effective against E. bieneusi. Fumagillin, an antibiotic and anti-angiogenic compound produced by Aspergillus fumigatus, is more broadly effective against Encephalitozoon spp. and Enterocytozoon bieneusi but is toxic when administered systemically to mammals. Gene target studies have focused on methionine aminopeptidase 2 (MetAP2) for characterizing the mechanism of action and for identifying more effective, less toxic fumagillin-related drugs. Polyamine analogues have shown promise in demonstrating anti-microsporidial activity in culture and in animal models, and a gene encoding topoisomerase IV was identified in Vittaforma corneae, raising prospects for studies on fluoroquinolone efficacy against microsporidia.
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Affiliation(s)
- Elizabeth S Didier
- Division of Microbiology, Tulane National Primate Research Center, Covington, LA 70433, USA.
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Curry A, Beeching NJ, Gilbert JD, Scott G, Rowland PL, Currie BJ. Trachipleistophora hominis infection in the myocardium and skeletal muscle of a patient with AIDS. J Infect 2004; 51:e139-44. [PMID: 16230193 DOI: 10.1016/j.jinf.2004.11.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2004] [Indexed: 11/16/2022]
Abstract
OBJECTIVES To review the literature relevant to microsporidial infection of muscle and to describe a case of human microsporidial infection involving both skeletal and cardiac muscle. METHODS Samples from an AIDS patient with myositis have been examined by light and electron microscopy. RESULTS We describe the findings at autopsy of a 47 year old Australian male with late stage AIDS, who had skeletal and cardiac muscle involvement with the microsporidian Trachipleistophora hominis. This is the third definitively identified case of human T. hominis infection and the first to describe infection of the myocardium. CONCLUSIONS Microsporidial infection of muscle is rare in humans, but more work is needed to elucidate both the organisms and routes of transmission of this group of parasitic protozoa.
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Affiliation(s)
- A Curry
- Health Protection Agency, Manchester Royal Infirmary, Clinical Sciences Building, Oxford Road, Manchester M13 9WL, UK.
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Rauz S, Tuft S, Dart JKG, Bonshek R, Luthert P, Curry A. Ultrastructural examination of two cases of stromal microsporidial keratitis. J Med Microbiol 2004; 53:775-781. [PMID: 15272065 DOI: 10.1099/jmm.0.45524-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two cases with chronic stromal keratitis are described in immunocompetent hosts where the diagnosis was originally thought to be herpetic or adenoviral disease. Light microscopy and ultrastructural examination of corneal tissue by electron microscopy were performed following penetrating keratoplasty (case 1) and corneal biopsy (case 2). Specimens from both cases were analysed for viral identification by PCR. Two different species of Microsporidia were identified. Case 1 represents the fourth reported case of corneal stromal Vittaforma corneae where the spores measured 3.3 x 1.4 microm, arranged in characteristic linear groups of about four to eight. Each spore contained a diplokaryotic nucleus and a single row of ten polar tube coils. By contrast, case 2 is the first reported case of stromal keratitis caused by Trachipleistophora hominis. In this case, spores measured 4 x 2.4 microm, located typically within packets. In this species, the polar tube was arranged as a single row of about 10-13 profiles. Viral DNA could not be amplified by PCR. In conclusion, microsporidial stromal keratitis should be considered in culture-negative cases refractory to medical therapy. As microbiological culture techniques are unsuccessful, diagnosis may only be established following histopathological and ultrastructural examination of corneal tissue.
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Affiliation(s)
- Saaeha Rauz
- Corneal and External Diseases Service, Moorfields Eye Hospital NHS Trust, City Road, London EC1V 2PD, UK 2,3Department of Histopathology2 and Health Protection Agency3, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WZ, UK
| | - Stephen Tuft
- Corneal and External Diseases Service, Moorfields Eye Hospital NHS Trust, City Road, London EC1V 2PD, UK 2,3Department of Histopathology2 and Health Protection Agency3, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WZ, UK
| | - John K G Dart
- Corneal and External Diseases Service, Moorfields Eye Hospital NHS Trust, City Road, London EC1V 2PD, UK 2,3Department of Histopathology2 and Health Protection Agency3, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WZ, UK
| | - Richard Bonshek
- Corneal and External Diseases Service, Moorfields Eye Hospital NHS Trust, City Road, London EC1V 2PD, UK 2,3Department of Histopathology2 and Health Protection Agency3, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WZ, UK
| | - Philip Luthert
- Corneal and External Diseases Service, Moorfields Eye Hospital NHS Trust, City Road, London EC1V 2PD, UK 2,3Department of Histopathology2 and Health Protection Agency3, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WZ, UK
| | - Alan Curry
- Corneal and External Diseases Service, Moorfields Eye Hospital NHS Trust, City Road, London EC1V 2PD, UK 2,3Department of Histopathology2 and Health Protection Agency3, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WZ, UK
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Abstract
OBJECTIVES To review and assess the role of electron microscopy in the investigation of new infectious diseases. DESIGN To design a screening strategy to maximize the likelihood of detecting new or emerging pathogens in clinical samples. RESULTS Electron microscopy remains a useful method of investigating some viral infections (infantile gastroenteritis, virus-induced outbreaks of gastroenteritis and skin lesions) using the negative staining technique. In addition, it remains an essential technique for the investigation of new and emerging parasitic protozoan infections in the immunocompromised patients from resin-embedded tissue biopsies. Electron microscopy can also have a useful role in the investigation of certain bacterial infections. CONCLUSIONS Electron microscopy still has much to contribute to the investigation of new and emerging pathogens, and should be perceived as capable of producing different, but equally relevant, information compared to other investigative techniques. It is the application of a combined investigative approach using several different techniques that will further our understanding of new infectious diseases.
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Affiliation(s)
- Alan Curry
- Electron Microscopy Unit, Manchester Royal Infirmary, Central Manchester Healthcare Trust, Manchester, UK.
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Cali A, Takvorian PM. Ultrastructure and development of Pleistophora ronneafiei n. sp., a microsporidium (Protista) in the skeletal muscle of an immune-compromised individual. J Eukaryot Microbiol 2003; 50:77-85. [PMID: 12744518 DOI: 10.1111/j.1550-7408.2003.tb00237.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This report provides a detailed ultrastructural study of the life cycle, including proliferative and sporogonic developmental stages, of the first Pleistophora species (microsporidium) obtained from an immune-incompetent patient. In 1985, the organism obtained from a muscle biopsy was initially identified as belonging to the genus Pleistophora, based on spore morphology and its location in a sporophorous vesicle. Since that initial report, at least two new microsporidial genera, Trachipleistophora and Brachiola, have been reported to infect the muscle tissue of immunologically compromised patients. Because Trachipleistophora development is similar to Pleistophora, and as Pleistophora was only known to occur in cold-blooded hosts, the question of the proper classification of this microsporidium arose. The information acquired in this study makes it possible to compare Pleistophora sp. (Ledford et al. 1985) to the known human infections and properly determine its correct taxonomic position. Our ultrastructural data have revealed the formation of multinucleate sporogonial plasmodia, a developmental characteristic of the genus Pleistophora and not Trachipleistophora. A comparison with other species of the genus supports the establishment of a new species. This parasite is given the name Pleistophora ronneafiei n. sp.
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Affiliation(s)
- Ann Cali
- Department of Biological Sciences, 101 Warren Street, Smith Hall, Rutgers University, Newark, New Jersey 07102, USA.
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Williams BAP, Hirt RP, Lucocq JM, Embley TM. A mitochondrial remnant in the microsporidian Trachipleistophora hominis. Nature 2002; 418:865-9. [PMID: 12192407 DOI: 10.1038/nature00949] [Citation(s) in RCA: 277] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Microsporidia are obligate intracellular parasites of several eukaryotes. They have a highly complex and unique infection apparatus but otherwise appear structurally simple. Microsporidia are thought to lack typical eukaryotic organelles, such as mitochondria and peroxisomes. This has been interpreted as support for the hypothesis that these peculiar eukaryotes diverged before the mitochondrial endosymbiosis, which would make them one of the earliest offshoots in eukaryotic evolution. But microsporidial nuclear genes that encode orthologues of typical mitochondrial heatshock Hsp70 proteins have been detected, which provides evidence for secondary loss of the organelle or endosymbiont. In addition, gene trees and more sophisticated phylogenetic analyses have recovered microsporidia as the relatives of fungi, rather than as basal eukaryotes. Here we show that a highly specific antibody raised against a Trachipleistophora hominis Hsp70 protein detects the presence, under light and electron microscopy, of numerous tiny ( approximately 50 x 90 nm) organelles with double membranes in this human microsporidial parasite. The finding of relictual mitochondria in microsporidia provides further evidence of the reluctance of eukaryotes to lose the mitochondrial organelle, even when its canonical function of aerobic respiration has been apparently lost.
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Affiliation(s)
- Bryony A P Williams
- Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
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32
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Abstract
Although attempts to develop methods for the in vitro cultivation of microsporidia began as early as 1937, the interest in the culture of these organisms was confined mostly to microsporidia that infect insects. The successful cultivation in 1969 of Encephalitozoon cuniculi, a microsporidium of mammalian origin, and the subsequent identification of these organisms as agents of human disease heightened interest in the cultivation of microsporidia. I describe the methodology as well as the cell lines, the culture media, and culture conditions used in the in vitro culture of microsporidia such as Brachiola (Nosema) algerae, Encephalitozoon cuniculi, E. hellem, E. intestinalis, Enterocytozoon bieneusi, Trachipleistophora hominis, and Vittaforma corneae that cause human disease.
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Affiliation(s)
- Govinda S Visvesvara
- Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3724, USA.
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33
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Lafranchi-Tristem NJ, Curry A, Cheney SA, Canning EU. Growth of Trachipleistophora hominis (Microsporidia: Pleistophoridae) in C2,C12 mouse myoblast cells and response to treatment with albendazole. Folia Parasitol (Praha) 2002; 48:192-200. [PMID: 11699654 DOI: 10.14411/fp.2001.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The microsporidium Trachipleistophora hominis Hollister, Canning, Weidner, Field, Kench et Marriott, 1996, originally isolated from human skeletal muscle cells, inhibited myotube formation from myoblasts when grown in a mouse myoblast cell line C2,C12. Uninfected cultures readily converted to myotubes. Albendazole, a drug with known antimicrosporidial activity, was tested against T. hominis in C2,C12 cells. The drug was added when infection had reached 75% of C2,C12 cells, a level comparable to that obtained in heavily infected muscle in vivo. Doses of 1 ng/ml and 10 ng/ml had no effect on merogony or sporogony. In cultures exposed to 100 ng/ml albendazole, the C2,C12 cells remained in good condition while infection levels dropped to 25% over 7 weeks. Drug doses of 500 ng/ml and 1,000 ng/ml were deleterious to the host cells but some spores retained viability and were able to establish new infections once albendazole pressure was removed. T. hominis meronts exposed to 100 ng/ml albendazole mostly lacked the normally thick surface coat and its reticulate extensions. Meronts were not seen in cultures exposed to higher drug doses. Albendazole at a concentration of 100 ng/ml and higher had a profound effect on spore morphogenesis. There was erratic coiling of the polar tube, often involving the formation of double tubes, and chaotic disposition of membranes which could have been those of polaroplast. The in vitro susceptibility of T. hominis to albendazole was low in comparison with in vitro susceptibility of other microsporidia of human origin.
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Affiliation(s)
- N J Lafranchi-Tristem
- Department of Biology, Imperial College of Science, Technology and Medicine, London, UK
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34
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Schottelius J, Kuhn EM, Enriquez R. Microsporidia and
Candida
spores: their discrimination by Calcofluor, trichrome‐blue and methylene‐blue combination staining. Trop Med Int Health 2001. [DOI: 10.1111/j.1365-3156.2000.tb00167.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. Schottelius
- Department of ParasitologyBernhard‐Nocht‐Institute for Tropical MedicineHamburgGermany
| | - E. M. Kuhn
- Biomedical Primate Research Centre (BPRC)RijswijkThe Netherlands
| | - R. Enriquez
- Universidad Austral de ChileFaculdad de Ciencias VeterinariasIctiopatologiaValdiviaChile
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35
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Abstract
Microsporidia are considered opportunistic pathogens in humans because they are most likely to cause diseases if the immune status of a host is such that the infection cannot be controlled. A wide spectrum of diseases has been reported among persons infected with microsporidia and different diagnostic techniques have been developed during the last decade.
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Affiliation(s)
- C Franzen
- Department of Internal Medicine I, University of Cologne, Joseph Stelzmann Str. 9, 50924, Cologne, Germany.
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36
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Dyková I, Lom J. Histopathology of Kabatana arthuri (Microspora) infection in sutchi catfish, Panagasius sutchi. Folia Parasitol (Praha) 2001; 47:161-6. [PMID: 11104142 DOI: 10.14411/fp.2000.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The microsporidian Kabatana arthuri (Lom, Dyková et Shaharom, 1990) induced severe regressive changes in trunk muscles of Pangasius sutchi (Fowler) from Thailand. Necrotic changes developed in muscle fibres around the developmental stages and on the periphery of giant aggregates of spores. The main feature of the host defence reaction was the phagocytic activity of macrophages. Inflammatory reaction was only exceptionally observed. Spore-laden macrophages were found in various tissues and organs; their infiltration in epidermis including its outermost layers may effectively enhance the spread of infection while the hosts still live.
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Affiliation(s)
- I Dyková
- Institute of Parasitology, Academy of Sciences of the Czech Republic, Ceské Budejovice.
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37
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Abstract
Microsporidia is a common term that has been used to refer to a group of eukaryotic, obligate intracellular protozoan parasites belonging to the phylum Microspora. They are important agricultural parasites, contaminating commercial insects; they are also important by infecting laboratory rodents, rabbits and primates. Ever since the early cases found by Magarino Torres, who reported the presence of Encephalitozoon in a patient suffering of a meningoencephalomyelitis, some human pathology caused by microsporidia has been described. However, only after the acquired immunodeficiency syndrome outbreak have these organisms appeared as significant etiological agents in different pathologies. Even so, they remain underestimated. In the present article, the importance of microsporidia for the human pathology in immunocompromised host has been stressed.
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Affiliation(s)
- J Schottelius
- Section of Parasitology, Bernhard-Nocht-Institute for Tropical Medicine, D-20359 Hamburg, Germany
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38
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Abstract
Microsporidia are eukaryotic spore forming obligate intracellular protozoan parasites first recognized over 100 years ago. These organisms infect all of the major animal groups and are now recognized as opportunistic pathogens of humans. Microsporidian spores are common in the environment and microsporidia pathogenic to humans have been found in water supplies. The genera Nosema, Vittaforma, Brachiola, Pleistophora, Encephalitozoon, Enterocytozoon, Septata (reclassified to Encephalitozoon) and Trachipleistophora have been found in human infections. These organisms have the smallest known eukaryotic genomes. Microsporidian ribosomal RNA sequences have proven useful as diagnostic tools as well as for phylogenetic analysis. Recent phylogenetic analysis suggests that Microsporidia are related to the fungi. These organisms are defined by the presence of a unique invasion organelle consisting of a single polar tube that coils around the interior of the spore. All microsporidia exhibit the same response to stimuli, that is, the polar tube discharges from the anterior pole of the spore in an explosive reaction. If the polar tube is discharged next to a cell, it can pierce the cell and transfer its sporoplasm into the cell. A technique was developed for the purification of polar tube proteins (PTPs) using differential extraction followed by reverse phase HPLC. This method was used to purify the PTPs from Glugea americanus, Encephalitozoon cuniculi, Enc. hellem and Enc. intestinalis. These PTPs demonstrate conserved characteristics such as solubility, hydrophobicity, mass, proline content and immunologic epitopes. The major PTP gene from Enc. cuniculi and Enc. hellem has been cloned and expressed in vitro. The gene sequences support the importance of ER and in the formation of the polar tube as suggested by morphologic studies. Analysis of the cloned proteins also indicates that secondary structural characteristics are conserved. These characteristics are probably important in the function of this protein during the eversion/assembly of the polar tube and in providing elasticity and resiliency for sporoplasm passage.
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Affiliation(s)
- L M Weiss
- Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue Room 504 Forchheimer Building, Bronx, New York, NY 10461, USA.
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39
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El Fakhry Y, Achbarou A, Franetich JF, Desportes-Livage I, Mazier D. Dissemination of Encephalitozoon intestinalis, a causative agent of human microsporidiosis, in IFN-gamma receptor knockout mice. Parasite Immunol 2001; 23:19-25. [PMID: 11136474 DOI: 10.1046/j.1365-3024.2001.00351.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The dissemination of Encephalitozoon intestinalis, a microsporidium causing intestinal diseases and systemic infection in humans, was investigated in IFN-gamma Ro/o mice. Although lesions were seen in organs of autopsied animals, the parasites were rarely detected using histological examination. Nevertheless, infection of the duodenum, liver, kidneys and lungs was demonstrated by polymerase chain reaction. This method also enabled the detection of the parasite in the brain and the heart. The development of E. intestinalis in RK13 cell cultures to which cell suspensions from liver, kidney, lung or brain of infected IFN-gamma Ro/o mice were added, confirmed the spread of intestinal microsporidiosis to these organs. No dissemination was observed in wild-type mice. These results confirm those of previous studies and emphasize the low morbidity of the infection in IFN-gamma Ro/o mice and confirm the role of IFN-gamma in the control of E. intestinalis infection. These mice infected with E. intestinalis offer important information about this interesting and important parasitic disease of man and animals.
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Affiliation(s)
- Y El Fakhry
- Centre de Recherche en Infectiologie, Faculté de Médecine de l'Université Laval, Ste-Foy, Québec, Canada.
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40
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Schottelius J, Hünger F, Schüler T, Gonçalves da Costa SC. Chitinolytic activity in viable spores of Encephalitozoon species. Mem Inst Oswaldo Cruz 2000; 95:701-5. [PMID: 10998219 DOI: 10.1590/s0074-02762000000500015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
By employing 4-methylumbelliferyl-beta-D-NN',N"-triacetylchitotriose substrate in a semi quantitative assay, chitinolytic activity in viable spores of Encephalitozoon cuniculi and E. intestinalis was detected and dependence on reaction time, spore concentration, concentration of substrate and temperature were demonstrated. It was possible to block the chitinolytic activity by chitin hydrolysate. By incubation at 80 degrees C for 10 min or at 55 degrees C for 20 min the spores were loosing the chitinolytic activity. Incubation of the spores in trypsin reduced the chitinolytic activity. Cellulase activity could not be detected.
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Affiliation(s)
- J Schottelius
- Section of Parasitology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
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41
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Hester JD, Lindquist HD, Bobst AM, Schaefer FW. Fluorescent in situ detection of Encephalitozoon hellem spores with a 6-carboxyfluorescein-labeled ribosomal RNA-targeted oligonucleotide probe. J Eukaryot Microbiol 2000; 47:299-308. [PMID: 10847348 DOI: 10.1111/j.1550-7408.2000.tb00051.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A fluorescent in situ hybridization assay has been developed for the detection of the human-pathogenic microsporidian, Encephalitozoon hellem in water samples using epifluorescence microscopy. The assay employs a 19-nucleotide species-specific 6-carboxyfluorescein-labeled oligonucleotide probe, HEL878F, designed to be complementary to the nucleic acid sequence 878-896, a highly variable segment of the 16S ribosomal RNA of E. hellem spores. The specificity of this probe for its ribosomal RNA target site was confirmed using RNA degradation, ribosomal RNA target site competition, and nucleotide base mismatch control probe assays. Furthermore, the specificity of the HEL878F oligonucleotide probe for E. hellem spores was established when it was evaluated on spores from all three species of the genus Encephalitozoon that had been seeded in reagent water and environmental water concentrates. The specificity of the HEL878F oligonucleotide probe was further corroborated when tested on algae, bacteria, and protozoa commonly found in environmental water. The study demonstrates the applicability of a fluorescent in situ hybridization assay using a species-specific fluorescent-labeled oligonucleotide probe for the detection of E. hellem spores in water samples.
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Affiliation(s)
- J D Hester
- Biohazard Assessment Research Branch, Microbiological and Chemical Exposure Assessment Research Division, National Exposure Research Laboratory, US Environmental Protection Agency, Cincinnati, Ohio 45268-1320, USA
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42
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Cheney SA, Lafranchi-Tristem NJ, Canning EU. Phylogenetic relationships of Pleistophora-like microsporidia based on small subunit ribosomal DNA sequences and implications for the source of trachipleistophora hominis infections. J Eukaryot Microbiol 2000; 47:280-7. [PMID: 10847345 DOI: 10.1111/j.1550-7408.2000.tb00048.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The microsporidian Trachipleistophora hominis was isolated in vitro from the skeletal muscle of an AIDS patient. Since its discovery several more cases of myositis due to Trachipleistophora have been diagnosed but the source of infection is unknown. Morphologically, T. hominis most closely resembles Pleistophora and Vavraia, which undergo polysporous sporogony in sporophorous vesicles, but differs from these genera in the mode of formation of sporoblasts and in the morphology of the sporophorous vesicles. Alignment and analyses of the small subunit ribosomal DNA sequences of T. hominis and several other polysporoblastic genera indicated that its closest phylogenetic relationships were with species of the genera Pleistophora and Vavraia, in line with morphological predictions. The type species of the latter two genera are Pleistophora typicalis and Vavraia culicis; these are parasites of fish and mosquitoes, respectively. These results suggest two possible routes and sources of infection to AIDS patients, these being perorally by ingestion of inadequately cooked fish or crustaceans or percutaneously during a bloodmeal taken by a haematophagous insect. Support for an insect source has been provided by recent detection of a microsporidium from mosquitoes in human corneal tissue.
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Affiliation(s)
- S A Cheney
- Department of Biology, Imperial College of Science, Technology and Medicine, London, United Kingdom
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43
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Abstract
Electron microscopy (EM) is still an important tool for the investigation of infectious diseases, despite the introduction of powerful new methods, mainly involving the polymerase chain reaction. Particularly in the field of parasitic protozoology associated with AIDS, where many new species of human pathogens have been recognized in tissue biopsies, EM remains an essential 'catch-all' diagnostic method. The resolved ultrastructural details of these newly recognized parasites allows a unique insight into the biology of these organisms. The information produced by EM is different, but complementary, to that provided by alternative methods.
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Affiliation(s)
- A Curry
- Public Health Laboratory, Withington Hospital, Manchester, UK
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44
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Abstract
The phylum Microspora contains a diverse group of single-celled, obligate intracellular protozoa sharing a unique organelle, the polar filament, and parasitizing a wide variety of invertebrate and vertebrate animals, including insects, fish, birds, and mammals. Encephalitozoon cuniculi is the classic microsporidial parasite of mammals, and encephalitozoonosis in rabbits and rodents has been and continues to be recognized as a confounding variable in animal-based biomedical research. Although contemporary research colonies are screened for infection with this parasite, E. cuniculi remains a cause of morbidity and mortality in pet and conventionally raised rabbits. In addition, E. cuniculi is a potential pathogen of immature domestic dogs and farm-raised foxes. The recent discovery and identification of Encephalitozoon intestinalis, Encephalitozoon hellem, and Enterocytozoon bieneusi, in addition to E. cuniculi, as opportunistic pathogens of humans have renewed interest in the Microspora. Veterinary pathologists, trained in the comparative anatomy of multiple animal species and infectious disease processes, are in a unique position to contribute to the diagnosis and knowledge of the pathogenesis of these parasitic diseases. This review article covers the life cycle, ultrastructure, and biology of mammalian microsporaidia and the clinical disease and lesions seen in laboratory and domestic animals, particularly as they relate to Encephalitozoon species. Human microsporidial disease and animal models of human infection are also addressed. Often thought of as rabbit pathogens of historical importance, E. cuniculi and the related mammalian microsporidia are emerging as significant opportunistic pathogens of immunocompromised individuals.
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Affiliation(s)
- K Wasson
- Office of Laboratory Animal Resources, University of Illinois, Urbana 61801, USA
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45
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Abstract
Sources of human microsporidial infection remain speculative, but possible animal reservoirs are emerging. Of the common human microsporidial infections, Enterocytozoon bieneusi has now been identified in non-human primates, pigs, dogs and a cat; Encephalitozoon intestinalis in dogs, pigs, cows, goats and donkeys and Encephalitozoon hellem in budgerigars and parrots. Evidence of species heterogeneity is also emerging suggesting that some animal isolates may be distinctive. Further molecular epidemiological studies need to be undertaken to clarify which animal genotypes can also infect humans. Some of the less common microsporidial infections found in humans, such as those involving Pleistophora-like species, may be the result of infrequent accidental exposure (for example, inadequately cooked infected fish muscle) and establishment, particularly if the individual is severely immunocompromised.
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Affiliation(s)
- A Curry
- Public Health Laboratory, Withington Hospital, Manchester, UK
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46
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Weidner E, Canning EU, Rutledge CR, Meek CL. Mosquito (Diptera: Culicidae) host compatibility and vector competency for the human myositic parasite Trachipleistophora hominis (Phylum Microspora). JOURNAL OF MEDICAL ENTOMOLOGY 1999; 36:522-525. [PMID: 10467783 DOI: 10.1093/jmedent/36.4.522] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Microsporidian spores of Trachipleistophora hominis Hollister, isolated from a human, readily infected larval stages of both Anopheles quadrimaculatus Say sensu lato and Culex quinque-fasciatus Say. Mosquito infections with T. hominis were located, primarily, in abdominal muscles in segment numbers 4 through 6; other spores were found in the hemocoel and proboscis. Nearly 50% of the infected mosquito larvae survived to the adult stage. Spores recovered from adult mosquitoes were inoculated into mice and resulted in significant muscle infection at the site of injection. Preliminary observations also showed that T. hominis spores can be passively transferred from infected mosquitoes to a sugar water substrate.
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Affiliation(s)
- E Weidner
- Department of Biological Sciences, Louisiana State University, Baton Rouge 70803, USA
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47
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Franzen C, Müller A. Molecular techniques for detection, species differentiation, and phylogenetic analysis of microsporidia. Clin Microbiol Rev 1999; 12:243-85. [PMID: 10194459 PMCID: PMC88917 DOI: 10.1128/cmr.12.2.243] [Citation(s) in RCA: 184] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microsporidia are obligate intracellular protozoan parasites that infect a broad range of vertebrates and invertebrates. These parasites are now recognized as one of the most common pathogens in human immunodeficiency virus-infected patients. For most patients with infectious diseases, microbiological isolation and identification techniques offer the most rapid and specific determination of the etiologic agent. This is not a suitable procedure for microsporidia, which are obligate intracellular parasites requiring cell culture systems for growth. Therefore, the diagnosis of microsporidiosis currently depends on morphological demonstration of the organisms themselves. Although the diagnosis of microsporidiosis and identification of microsporidia by light microscopy have greatly improved during the last few years, species differentiation by these techniques is usually impossible and transmission electron microscopy may be necessary. Immunfluorescent-staining techniques have been developed for species differentiation of microsporidia, but the antibodies used in these procedures are available only at research laboratories at present. During the last 10 years, the detection of infectious disease agents has begun to include the use of nucleic acid-based technologies. Diagnosis of infection caused by parasitic organisms is the last field of clinical microbiology to incorporate these techniques and molecular techniques (e.g., PCR and hybridization assays) have recently been developed for the detection, species differentiation, and phylogenetic analysis of microsporidia. In this paper we review human microsporidial infections and describe and discuss these newly developed molecular techniques.
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Affiliation(s)
- C Franzen
- Department of Internal Medicine I, University of Cologne, 50924 Cologne,
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48
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Moss DM, Croppo GP, Wallace S, Visvesvara GS. Flow cytometric analysis of microsporidia belonging to the genus Encephalitozoon. J Clin Microbiol 1999; 37:371-5. [PMID: 9889221 PMCID: PMC84311 DOI: 10.1128/jcm.37.2.371-375.1999] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flow cytometry was used in the identification of human microsporidia belonging to the genus Encephalitozoon. Microsporidian spores of Encephalitozoon hellem, E. cuniculi, and E. intestinalis were propagated in axenic cultures of monkey kidney E6 cells, purified with Percoll, and exposed to homologous and heterologous rabbit antiserum and monoclonal antibody prepared against E. hellem spores. After reaction to goat anti-rabbit immunoglobulin G (IgG) or goat anti-mouse IgG conjugated to fluorescein isothiocyanate, fluorescence histograms from gated data on light-scatter profiles showed that rabbit anti-E. hellem serum was reactive to E. hellem spores but also had cross-reactivity to spores of E. cuniculi and E. intestinalis. On the other hand, fluorescence histograms showed that rabbit anti-E. cuniculi and rabbit anti-E. intestinalis sera were reactive with homologous spores only. Monoclonal antibody prepared against E. hellem reacted only with spores of E. hellem. Neither the polyclonal antibodies nor the monoclonal antibodies reacted with Cryptosporidium parvum oocysts. Fluorescence histograms of spores treated with 10% formalin also showed reactivity, but the number of events in the most intense peaks of fluorescence was fewer (7 to 42%, depending on species) than the number of events in the most intense peaks of fluorescence for nontreated spores. By flow cytometry, formalin-treated and nontreated spores of Encephalitozoon were identified to the species level by using gated data on light-scatter profiles and analyzing the fluorescence histograms from the indirect immunofluorescence of the spores. Once a procedure is established for the isolation of Encephalitozoon spores from clinical specimens, identification of spores by flow cytometry may be useful not only for diagnosis but also for epidemiologic studies.
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Affiliation(s)
- D M Moss
- Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
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49
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Kondova I, Mansfield K, Buckholt MA, Stein B, Widmer G, Carville A, Lackner A, Tzipori S. Transmission and serial propagation of Enterocytozoon bieneusi from humans and Rhesus macaques in gnotobiotic piglets. Infect Immun 1998; 66:5515-9. [PMID: 9784565 PMCID: PMC108691 DOI: 10.1128/iai.66.11.5515-5519.1998] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/1998] [Accepted: 07/15/1998] [Indexed: 11/20/2022] Open
Abstract
For over a decade Enterocytozoon bieneusi infections in people with AIDS have been linked with chronic diarrhea and wasting. The slow scientific progress in treating these infections is attributed to the inability of investigators to cultivate the parasite, which has also precluded evaluation of effective therapies. We report here successful serial transmissions of E. bieneusi from patients with AIDS and from macaques with AIDS to immunosuppressed gnotobiotic piglets. One infected piglet was still excreting spores at necropsy 50 days after an oral challenge. Spores in feces were detected microscopically by trichrome stain and by PCR and within enterocytes by in situ hybridization and immunohistochemistry. E. bieneusi infection induced no symptoms. The development of an animal model for E. bieneusi will open up new opportunities for investigating this parasite.
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Affiliation(s)
- I Kondova
- Division of Infectious Disease, Tufts University School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA
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50
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Vávra J, Yachnis AT, Shadduck JA, Orenstein JM. Microsporidia of the genus Trachipleistophora--causative agents of human microsporidiosis: description of Trachipleistophora anthropophthera n. sp. (Protozoa: Microsporidia). J Eukaryot Microbiol 1998; 45:273-83. [PMID: 9627987 DOI: 10.1111/j.1550-7408.1998.tb04536.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Trachipleistophora anthropophthera n. sp., was found at autopsy in the brain of one and in the brain, kidneys, pancreas, thyroid, parathyroid, heart, liver, spleen, lymph nodes, and bone marrow of a second patient with AIDS. The parasite is similar to the recently described T. hominis Hollister, Canning, Weidner, Field, Kench and Marriott, 1996, in having isolated nuclei, meronts with a thick layer of electron dense material on the outer face of their plasmalemma and sporogony during which spores are formed inside a thick-walled sporophorous vesicle. In contrast to T. hominis, this species is dimorphic as it forms two kinds of sporophorous vesicles and spores: Type I--round to oval polysporous sporophorous vesicle, 7-10 microns in size, usually with eight spores (3.7 x 2.0 microns), thick endospores, subterminal anchoring disc and anisofilar polar filaments forming seven thicker and two thinner terminal coils. This type of sporophorous vesicle is associated with 25-30 nm filaments extending into the host cell cytoplasm. Type II--smaller, bisporous sporophorous vesicle (4-5 x 2.2-2.5 microns) with two, nearly round, thin-walled spores, 2.2-2.5 x 1.8-2.0 microns in size, having 4-5 isofilar coils. No outside filamentous elements are associated with the bisporous sporophorous vesicle. Both types of sporophorous vesicles were common in the infected brain tissue and could be found within the same cell. The newly described species, together with T. hominis and previously reported Pleistophora-like parasites from human muscle, likely represent a group of closely related human microsporidia.
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Affiliation(s)
- J Vávra
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
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