title: Development, ultrastructural pathology, and taxonomic revision of the Microsporidial genus, Pseudoloma and its type species Pseudoloma neurophilia, in skeletal muscle and nervous tissue of experimentally infected zebrafish Danio rerio.
abstract: The microsporidium Pseudoloma neurophilia was initially reported to infect the central nervous system of zebrafish causing lordosis and eventually death. Subsequently, muscle tissue infections were also identified. To understand the infection process, development, and ultrastructural pathology of this microsporidium, larval and adult zebrafish were fed P. neurophilia spores. Spores were detected in the larval fish digestive tract 3-h postexposure (PE). By 4.5-d PE, developing parasite stages were identified in muscle tissue. Wet preparations of larvae collected at 8-d PE showed aggregates of spores in the spinal cord adjacent to the notochord. All parasite stages, including spores, were present in the musculature of larval fish 8-d PE. Adult zebrafish sacrificed 45-d PE had fully developed infections in nerves. Ultrastructural study of the developmental cycle of P. neurophilia revealed that proliferative stages undergo karyokinesis, producing tetranucleate stages that then divide into uninucleate cells. The plasmalemma of proliferative cells has a previously unreported glycocalyx-like coat that interfaces with the host cell cytoplasm. Sporogonic stages form sporophorous vacuoles (SPOV) derived from the plasmalemmal dense surface coat, which "blisters" off sporonts. Uninucleate sporoblasts and spores develop in the SPOV. The developmental cycle is identical in both nerve and muscle. The SPOV surface is relatively thick and is the outermost parasite surface entity; thus, xenomas are not formed. Based on the new information provided by this study, the taxonomic description of the genus Pseudoloma and its type species, P. neurophilia, is modified and its life cycle described.
authors.affiliation: Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102, USA. anncali@andromeda.rutgers.edu
authors.forename: Ann
authors.initials: A
authors.lastname: Cali
authors.forename: Michael
authors.initials: M
authors.lastname: Kent
authors.forename: Justin
authors.initials: J
authors.lastname: Sanders
authors.forename: Cyrilla
authors.initials: C
authors.lastname: Pau
authors.forename: Peter M
authors.initials: PM
authors.lastname: Takvorian
mesh_terms: D000818:Animals; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D008853:Microscopy; D021861:Microsporidia, Unclassified / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000382:microbiology / Q000473:pathology; D009420:Nervous System / Q000382:microbiology / Q000473:pathology; D012331:RNA, Fungal / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D015027:Zebrafish / Q000382:microbiology*
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D012331:RNA, Fungal; D012337:RNA, Ribosomal, 18S
references.citation: Folia Parasitol (Praha). 2005 May;52(1-2):63-8
references.pmid: 16004365
references.citation: Dis Aquat Organ. 2009 Dec 22;88(1):69-84
references.pmid: 20183967
references.citation: In Vitro Cell Dev Biol Anim. 2009 Mar-Apr;45(3-4):135-47
references.pmid: 19184249
references.citation: J Fish Dis. 2003 Jul;26(7):423-6
references.pmid: 12946012
references.citation: J Eukaryot Microbiol. 2001 Mar-Apr;48(2):227-33
references.pmid: 12095112
references.citation: Crit Rev Microbiol. 1992;18(5-6):285-395
references.pmid: 1476619
references.citation: Syst Parasitol. 2002 Oct;53(2):81-99
references.pmid: 12386417
references.citation: Dis Aquat Organ. 2011 May 24;95(1):73-9
references.pmid: 21797038