Ultrastructural and molecular characterization of Glugea serranus n. sp., a microsporidian infecting the blacktail comber, Serranus atricauda (Teleostei: Serranidae), in the Madeira Archipelago (Portugal)
A new microsporidian infecting the connective tissue of the coelomic cavity of the blacktail comber Serranus atricauda, in the Madeira Archipelago (Portugal), is described on the basis of morphological, ultrastructural, and molecular features. The microsporidian formed large whitish xenomas adhering to the peritoneal visceral organs of the host. Each xenoma consisted of a single hypertrophic cell, in the cytoplasm of which mature spores proliferated within parasitophorous vacuoles surrounded by numerous collagen fibers. Mature spores were ellipsoidal and uninucleated, measuring an average of 6.5 ± 0.5 μm in length and 3.4 ± 0.6 μm in width. The anchoring disk of the polar filament was subterminal, laterally shifted from the anterior pole of the spore. The isofilar polar filament coiled in 18–19 turns, forming two rows that surrounded the posterior vacuole. The latter occupied about one third of the spore length. The polaroplast surrounding the apical and uncoiled portion of the polar filament displayed two distinct regions: a lamellar region and an electron-dense globule. Molecular analysis of the rRNA genes, including the internal transcribed spacer region, and phylogenetic analysis using maximum likelihood and neighbor joining demonstrated that this microsporidian parasite clustered with some Glugea species. Based on the differences found both at the morphological and molecular levels, to other members of the genus Glugea, the microsporidian infecting the blacktail comber is considered a new species, thus named Glugea serranus n. sp.
KeywordsFish parasite Microsporidia Fine structure rRNA genes
This work was partially supported by Eng. António Almeida Foundation (Porto, Portugal); FCT (Lisbon, Portugal), within the scope of the PhD fellowship grant attributed to S. Rocha (SFRH/BD/92661/2013) through the program QREN-POPH/FSE; and the project no. PRG-1436-02 of King Saud University (Riyadh, Saudi Arabia). We are grateful to Dr. Paulo Oliveira, director of the Natural Park of Madeira, for permission to catch the samples of blacktail comber, from the coastal waters of the Selvagens Nature Reserve, and to the Nature Ranger, Mr. Jacques, for help with the line fishing. This work complies with the current laws of the country where it was performed. The helpful comments and suggestions of the reviewers were greatly appreciated.
- Abdel-Baki A-AS, Al-Quraishy S, Rocha S, Dkhil MA, Casal G, Azevedo C (2015a) Ultrastructure and phylogeny of Glugea nagelia sp. n. (Microsporidia: Glugeidae), infecting the intestinal wall of the yellowfin hind, Cephalopholis hemistiktos (Actinopterygii, Serranidae), from the Red Sea. Folia Parasitol 62:007, doi: 10.14411/fp.2015.007 CrossRefGoogle Scholar
- Brown AMV, Kent ML, Adamson ML (2010) Description of five new Loma (Microsporidia) species in Pacific fishes with redesignation of the type species Loma morhua Morrison & Sprague, 1981, based on morphological and molecular species-boundaries tests. J Eukaryot Microbiol 57:529–553. doi: 10.1111/j.1550-7408.2010.00508.x CrossRefPubMedGoogle Scholar
- Canning EU, Lom J (1986) The microsporidia of vertebrates. Academic, LondonGoogle Scholar
- Canning EU, Lom J, Nicholas JP (1982) Genus Glugea Thélohan 1891 (phylum Microspora): redescription of the type species Glugea anomala (Moniez 1887) and recognition of its sporogonic development within sporophorous vesicles (pansporoblastic membranes). Protistologica 18:193–210Google Scholar
- Jithendran KP, Vijayan KK, Kailasam M (2011) Microsporidian (Glugea sp.) infection in the greasy grouper Epinephelus tauvina (Forsskal, 1775). Indian J Fish 58:125–127Google Scholar
- Larsson JIR (1999) Identification of microsporidia. Acta Protozool 39:161–197Google Scholar
- Lom J, Dyková I (1992) Microsporidia (phylum Microspora Sprague, 1977). In: Lom J, Dyková I (eds) Protozoan parasites of fishes. Developments in Aquaculture and Fisheries Science, Amsterdam: Elsevier, p 125–157Google Scholar
- Marzouk MS, Anter OM, Ali MM, Kenawy AM, Mahmaud MA (2010) Studies on epizootic microsporidiosis in wild dusky grouper (Epinephelus guaza) from Mediterranean Sea at Matrouh Governorate, Egypt. Egypt J Aquat Biol Fish 14:1–12Google Scholar
- Nagasawa K, Cruz-Lacierda ER (2004) Diseases of cultured groupers. Southeast Asian Fisheries Development Center, Aquaculture Department. Government of Japan Trust Fund, Iloilo, PhilippinesGoogle Scholar
- Payghan R, Nabavi L, Jamshidi K, Akbari S (2009) Microsporidian infection in lizard fish, Saurida undosquamis of Persian Gulf. Iranian J Vet Res 10:180–185Google Scholar
- Wu HB, Wu YS, Wu ZH (2005) Occurrence of a new microsporidian in the abdominal cavity of Epinephelus akaara. Acta Hydrobiol 29:150–154Google Scholar
- Zhang JY, Wu YS, Lu YS, Wang JG (2004) Advance in research of fish microsporidia. Acta Hydrobiol Sinica 28:563–568Google Scholar