Redefining the genus Spraguea based on ultrastructural and phylogenetic data from Spraguea gastrophysus n. sp. (Phylum Microsporidia), a parasite found in Lophius gastrophysus (Teleostei) from Brazil

Abstract

The ultrastructure of the fish-infecting microsporidium Spraguea gastrophysus found in the dorsal ganglia and kidney of the anglerfish, Lophius gastrophysus (family Lophiidae) collected on the Brazilian Atlantic coast is described. Each whitish xenoma (up to 3.1 × 1.8 mm) contains several groups of parasites. The host cells are hypertrophied and contain various parasite life stages including mature spores and several developmental stages with unpaired nuclei. Monomorphic spores are ellipsoidal, lightly curved and measure about 3.35 × 1.71 μm. The spore contains a gradually tapering isofilar polar filament with five to six coils arranged in a single row. The nucleus occupies a central zone of the sporoplasm where also several polyribosomes are presented. The posterior vacuole contains a voluminous spherical and granular posterosome measuring up to ~0.65 μm in diameter. The partial small subunit, intergenic spacer and partial large subunit rRNA gene were sequenced and the phylogenetic analysis places the microsporidian described here in the clade that includes all sequences of the Spraguea genus. The ultrastructural morphology of the xenoma and the spores of this microsporidian parasite, as well as the molecular and phylogenetic analysis, suggest the description of a new species. A redefining of the genus Spraguea is also done.

Morphological and ultrastructural description of Pleistophora dammami sp. n. infecting the intestinal wall of Saurida undosquamis from the Arabian Gulf, Saudi Arabia

“…The parasite described in this paper presents the typical morphology and characteristics of the phylum Microsporidia (Pekkarinen 1996;Lom 2002;Abdel-Ghaffar et al 2012;Casal et al 2012). The classification of the Phylum Microspora is entirely based on ultrastructural characteristics (Canning and Lom 1986;Nilsen et al 1998;Abdel-Ghaffar et al 2009, with keys for generic differentiation having been prepared by Weiser (1989), Pekkarinen et al (2002) and Lom and Dyková (2005).…”

Microsporidians xenomas of anglerfish from NE Atlantic waters

“…Recently , S. gastrophysus was also described infecting the dorsal ganglia and kidney of L. gastrophysus from Brazil (Casal et al . ). Miwa et al .…”

“…This species was also described infecting the nervous tissues of the Japanese anglerfish L. litulon (Freeman et al 2004). Recently, S. gastrophysus was also described infecting the dorsal ganglia and kidney of L. gastrophysus from Brazil (Casal et al 2012). Miwa et al (2011) reported an encephalomyelitis associated with a microsporidian infection in Seriola dumerili, which was identified as Spraguea spp.…”

“…Among microsporidia, the genus Spraguea was recently redefined as a monophyletic group of species that infect ganglion cells and it is associated with nervous tissues along the vertebral spine of Lophiid species (Casal et al 2012). The infection of S. lophii is macroscopically visible as characteristic xenoparasitic complexes or cysts containing large numbers of xenomas harbouring thousands of spores.…”

“…The infection of S. lophii is macroscopically visible as characteristic xenoparasitic complexes or cysts containing large numbers of xenomas harbouring thousands of spores. These cysts measure from millimetres to several centimetres across (Amig o et al 1995;Freeman, Yokoyama & Ogawa 2004;Casal et al 2012;Mansour et al 2013;Colmenero et al 2015).…”