A microsporidian parasite of the genus Spraguea in the nervous tissues of the Japanese anglerfish Lophius litulon

Abstract

Abstract. In the present study, a high percentage of Japanese anglerfish, Lophius litulon (Jordan, 1902), contained a microsporidian infection of the nervous tissues. Xenomas were removed and prepared for standard wax histology and transmission electron microscopy (TEM). DNA extractions were performed on parasite spores and used in PCR and sequencing reactions. Fresh spores measured 3.4 × 1.8 µm and were uniform in size with no dimorphism observed. TEM confirmed that only a single developmental cycle and a single spore form were present. Small subunit (SSU) rDNA sequences were >99.5% similar to those of Spraguea lophii (Doflein, 1898) and Glugea americanus (Takvorian et Cali, 1986) from the European and American Lophius spp. respectively. The microsporidian from the nervous tissue of L. litulon undoubtedly belongs in the genus Spraguea Sprague et Vávra, 1976 and the authors suggest a revision to the generic description of Spraguea to include monomorphic forms and the transfer of Glugea americanus to Spraguea americana comb. n. Since no major differences in ultrastructure or SSU rDNA sequence data exist between Spraguea americana and the microsporidian from the Japanese anglerfish, they evidently belong to the same species. This report of Spraguea americana is the first report of a Spraguea species from L. litulon and indeed from the Pacific water mass.

Microsporidian xenomas in fish seen in wider perspective

“…It also shows clearly the problems of morphological taxonomy of microsporidia and the existence of an intraspecies polymorphism associated with a particular host. This has been again confirmed by the findings of Freeman et al (2004) that Spraguea lophii populations in species of the genus Lophius, other than L. piscatorius and L. budegassa, may not display spore dimorphism ("nosema" and "nosemoides" type of spores) as found in the type host. Further studies on the host specificity and intraspecific variation of xenoma-forming microsporidia is warranted.…”

Phylogeny and morphology of Glugea hertwigi from rainbow smelt Osmerus mordax found in Prince Edward Island, Canada

“…Although G. hert-wigi has been documented in smelt populations throughout Europe and the Atlantic, morphological and molecular data on the parasite are currently lacking. Microsporidia in the genus Glugea have been considered problematic; however, it has been demonstrated that G. anomala and G. stephani are likely the same species, whereas G. americanus belongs in fact to the genus Spraguea (Pomport-Castillon et al 2000, Freeman et al 2004. In the present study, G. hertwigi from O. mordax is characterized with transmission electron microscopy (TEM) and ribosomal DNA (rDNA) sequences to determine its relatedness within the genus Glugea.…”

“…sequences. The sequence deposited in GenBank under the name G. americanus was considered to be Spraguea americana (Freeman et al 2004). The identity of the sequences calculated for Glugea spp.…”

Zoothamnium duplicatum infestation of cultured horseshoe crabs (Limulus polyphemus)

“…Post-treatment, DNA was extracted using a GeneMATRIX DNA extraction kit (EURx Poland) following the manufacturer's tissue protocol. Partial small subunit ribosomal DNA (SSU rDNA) sequences were amplified using the universal primers 390f, 870r (its complementary forward primer 870f) and 18gM, for which primer sequences and PCR conditions have been described (Freeman et al, 2004;Freeman and Ogawa, 2010). PCRs were performed in triplicate.…”