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FEMS Microbiology Reviews May 2012The microsporidia are a diverse phylum of obligate intracellular parasites related to the fungi that cause significant and sometimes life-threatening disease in... (Review)
Review
The microsporidia are a diverse phylum of obligate intracellular parasites related to the fungi that cause significant and sometimes life-threatening disease in immune-compromised hosts, such as AIDS and organ transplant patients. More recently, their role in causing pathology in immune-competent populations has also been appreciated. Interestingly, in several instances, the microsporidia have been shown to persist in their hosts long term, causing at opposite ends of the spectrum either an intractable chronic diarrhea and wasting in patients with advanced-stage AIDS or asymptomatic shedding of spores in healthy populations. Much remains to be studied regarding the immune response to these pathogens, but it seems clear that CD8+ T cells are essential in clearing infection. However, in the infection models examined thus far, the role for CD4+ T cells is unclear at best. Here, we discuss the possible reasons and ramifications of what may be a weak primary CD4+ T cell response against Encephalitozoon cuniculi. Given the central role of the CD4+ T cell in other models of adaptive immunity, a better appreciation of its role in responding to microsporidia may provide insight into the survival strategies of these pathogens, which allow them to persist in hosts of varied immune status.
Topics: CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Chronic Disease; Host-Pathogen Interactions; Humans; Microsporidia; Microsporidiosis
PubMed: 22126330
DOI: 10.1111/j.1574-6976.2011.00318.x -
Cellular Microbiology Nov 2009Microsporidia are intracellular parasites of all major animal lineages and have a described diversity of over 1200 species and an actual diversity that is estimated to... (Review)
Review
Microsporidia are intracellular parasites of all major animal lineages and have a described diversity of over 1200 species and an actual diversity that is estimated to be much higher. They are important pathogens of mammals, and are now one of the most common infections among immunocompromised humans. Although related to fungi, microsporidia are atypical in genomic biology, cell structure and infection mechanism. Host cell infection involves the rapid expulsion of a polar tube from a dormant spore to pierce the host cell membrane and allow the direct transfer of the spore contents into the host cell cytoplasm. This intimate relationship between parasite and host is unique. It allows the microsporidia to be highly exploitative of the host cell environment and cause such diverse effects as the induction of hypertrophied cells to harbour prolific spore development, host sex ratio distortion and host cell organelle and microtubule reorganization. Genome sequencing has revealed that microsporidia have achieved this high level of parasite sophistication with radically reduced proteomes and with many typical eukaryotic pathways pared-down to what appear to be minimal functional units. These traits make microsporidia intriguing model systems for understanding the extremes of reductive parasite evolution and host cell manipulation.
Topics: Animals; Host-Parasite Interactions; Humans; Mammals; Microsporidia; Models, Biological; Virulence
PubMed: 19673893
DOI: 10.1111/j.1462-5822.2009.01362.x -
Microbes and Infection Apr 2001Microsporidia are amitochondrial eukaryotic obligate intracellular parasites. They are reported to infect every animal group from protists to vertebrates, including... (Review)
Review
Microsporidia are amitochondrial eukaryotic obligate intracellular parasites. They are reported to infect every animal group from protists to vertebrates, including humans. Microsporidia are of interest as opportunistic pathogens in humans and for certain characteristics which raise questions about their evolution and phylogenetic position. This review describes the basic biology and invasion mechanisms of microsporidian species infecting humans.
Topics: Animals; Eukaryotic Cells; Evolution, Molecular; Genes, Protozoan; Life Cycle Stages; Microsporidia; Microsporidiosis; Opportunistic Infections; Phylogeny
PubMed: 11369274
DOI: 10.1016/s1286-4579(01)01393-4 -
Experientia Supplementum (2012) 2022Microsporidia are obligate intracellular pathogens that were initially identified about 160 years ago. Current phylogenetic analysis suggests that they are grouped with...
Microsporidia are obligate intracellular pathogens that were initially identified about 160 years ago. Current phylogenetic analysis suggests that they are grouped with Cryptomycota as a basal branch or sister group to the fungi. Microsporidia are found worldwide and can infect a wide range of animals from invertebrates to vertebrates, including humans. They are responsible for a variety of diseases once thought to be restricted to immunocompromised patients but also occur in immunocompetent individuals. The small oval spore containing a coiled polar filament, which is part of the extrusion and invasion apparatus that transfers the infective sporoplasm to a new host, is a defining characteristic of all microsporidia. When the spore becomes activated, the polar filament uncoils and undergoes a rapid transition into a hollow tube that will transport the sporoplasm into a new cell. The polar tube has the ability to increase its diameter from approximately 100 nm to over 600 nm to accommodate the passage of an intact sporoplasm and penetrate the plasmalemma of the new host cell. During this process, various polar tube proteins appear to be involved in polar tube attachment to host cell and can interact with host proteins. These various interactions act to promote host cell infection.
Topics: Animals; Cytoplasm; Humans; Microsporidia; Phylogeny; Spores, Fungal
PubMed: 35544004
DOI: 10.1007/978-3-030-93306-7_8 -
The Journal of Eukaryotic Microbiology 2003
Topics: Animals; Animals, Domestic; Animals, Zoo; Antiprotozoal Agents; Microsporidia; Microsporidiosis
PubMed: 14736164
DOI: 10.1111/j.1550-7408.2003.tb00631.x -
Current Protocols May 2024Nematodes are naturally infected by the fungal-related pathogen microsporidia. These ubiquitous eukaryotic parasites are poorly understood, despite infecting most types...
Nematodes are naturally infected by the fungal-related pathogen microsporidia. These ubiquitous eukaryotic parasites are poorly understood, despite infecting most types of animals. Identifying novel species of microsporidia and studying them in an animal model can expedite our understanding of their infection biology and evolution. Nematodes present an excellent avenue for pursuing such work, as they are abundant in the environment and many species are easily culturable in the laboratory. The protocols presented here describe how to isolate bacterivorous nematodes from rotting substrates, screen them for microsporidia infection, and molecularly identify the nematode and microsporidia species. Additionally, we detail how to remove environmental contaminants and generate a spore preparation of microsporidia from infected samples. We also discuss potential pitfalls and provide suggestions on how to mitigate them. These protocols allow for the identification of novel microsporidia species, which can serve as an excellent starting point for genomic analysis, determination of host specificity, and infection characterization. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Gathering samples Support Protocol 1: Generating 10× and 40× Escherichia coli OP50 and seeding NGM plates Basic Protocol 2: Microsporidia screening, testing for Caenorhabditis elegans susceptibility, and sample freezing Basic Protocol 3: DNA extraction, PCR amplification, and sequencing to identify nematode and microsporidia species Basic Protocol 4: Removal of contaminating microbes and preparation of microsporidia spores Support Protocol 2: Bleach-synchronizing nematodes.
Topics: Animals; Microsporidia; Nematoda; Caenorhabditis elegans; DNA, Fungal; Polymerase Chain Reaction; Microsporidiosis; Spores, Fungal
PubMed: 38727641
DOI: 10.1002/cpz1.1035 -
Parazitologiia 2016
Review
Topics: Animals; Copepoda; Culicidae; Host-Pathogen Interactions; Microsporidia; Species Specificity
PubMed: 29215226
DOI: No ID Found -
Trends in Parasitology Aug 2021
Topics: Animals; Humans; Microsporidia; Microsporidiosis
PubMed: 33941494
DOI: 10.1016/j.pt.2021.04.003 -
Contributions To Microbiology 2000
Review
Topics: Animals; Bird Diseases; Birds; Humans; Microsporidia; Microsporidiosis; Zoonoses
PubMed: 10943515
DOI: 10.1159/000060363 -
Microbial Ecology Aug 2021Microsporidia are obligate parasites that are closely related to Fungi. While the widely known "long-branch" Microsporidia infect mostly metazoans, the hosts of...
Microsporidia are obligate parasites that are closely related to Fungi. While the widely known "long-branch" Microsporidia infect mostly metazoans, the hosts of "short-branch" Microsporidia are only partially characterized or not known at all. Here, we used network analyses from Neotropical rainforest soil metabarcoding data, to infer co-occurrences between environmental lineages of short-branch microsporidians and their potential hosts. We found significant co-occurrences with several taxa, especially with Apicomplexa, Cercozoa, and Fungi, as well as some Metazoa. Our results are the first step to identify potential hosts of the environmental lineages of short-branch microsporidians, which can be targeted in future molecular and microscopic studies.
Topics: Cercozoa; Microsporidia; Phylogeny; Rainforest; Soil
PubMed: 33420911
DOI: 10.1007/s00248-020-01657-9