title: Microsporidia: biology and evolution of highly reduced intracellular parasites.
abstract: Microsporidia are a large group of microbial eukaryotes composed exclusively of obligate intracellular parasites of other eukaryotes. Almost 150 years of microsporidian research has led to a basic understanding of many aspects of microsporidian biology, especially their unique and highly specialized mode of infection, where the parasite enters its host through a projectile tube that is expelled at high velocity. Molecular biology and genomic studies on microsporidia have also drawn attention to many other unusual features, including a unique core carbon metabolism and genomes in the size range of bacteria. These seemingly simple parasites were once thought to be the most primitive eukaryotes; however, we now know from molecular phylogeny that they are highly specialized fungi. The fungal nature of microsporidia indicates that microsporidia have undergone severe selective reduction permeating every level of their biology: From cell structures to metabolism, and from genomics to gene structure, microsporidia are reduced.
authors.affiliation: Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, Vancouver BC, V6T 1Z4, Canada. pkeeling@interchange.ubc.ca
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Keeling
authors.forename: Naomi M
authors.initials: NM
authors.lastname: Fast
mesh_terms: D000818:Animals; D002244:Carbon / Q000378:metabolism; D019143:Evolution, Molecular; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D016814:Microsporidia / Q000235:genetics / Q000254:growth & development*; D016881:Microsporidiosis / Q000378:metabolism; D008954:Models, Biological; D010802:Phylogeny; D013172:Spores, Fungal / Q000166:cytology / Q000254:growth & development / Q000378:metabolism
chemical_list: D002244:Carbon