Ultrastructural and phylogenetic description of Zschokkella auratis sp nov (Myxozoa), a parasite of the gilthead seabream Sparus aurata

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Rocha, S (Author) Other; Casal, G (Author) Other; Rangel, L (Author) Other; Severino, R (Author) Other; Castro, R (Author) Other; Azevedo, C (Author) Other; Santos, MJ (Author) FCUP

Journal

Title: Diseases of Aquatic Organisms

Vol. 107

Pages: 19-30

ISSN: 0177-5103

Publisher: Inter-Research Science Publishing

Indexing

ISI Web of Knowledge - 17 Citations

Scopus - 18 Citations

Other information

Authenticus ID: P-008-JR3

DOI: 10.3354/dao02661

Abstract (EN): A new myxosporean, Zschokkella auratis sp. nov., infecting the gall bladder of the gilthead seabream Sparus aurata in a southern Portuguese fish farm, is described using microscopic and molecular procedures. Plasmodia and mature spores were observed floating free in the bile. Plasmodia, containing immature and mature spores, were characterized by the formation of branched glycostyles, apparently due to the release of segregated material contained within numerous cytoplasmic vesicles. Mature spores were ellipsoidal in sutural view and slightly semicircular in valvular view, with rounded ends, measuring 9.5 +/- 0.3 SD ( 8.7-10.3) mu m in length and 7.1 +/- 0.4 ( 6.5-8.0) mu m in width/thickness. The spore wall was composed of 2 symmetrical valves united along a slightly curved suture line, each displaying 10 to 11 elevated surface ridges. Two equal sub-spherical polar capsules, 3.7 +/- 0.3 ( 3.0-4.1) mu m long and 3.0 +/- 0.2 ( 2.6-3.2) mu m wide, were located separately at the spore's extremities. Each polar capsule contained a polar filament forming 4 to 5 coils. The sporoplasm was binucleate and contained numerous sporoplasmosomes. Morphological data, tissue tropism, and molecular analysis of the small subunit rDNA gene identified this parasite as a new species of Zschokkella. Maximum parsimony, neighbor-joining, and maximum likelihood inferences clustered the parasite in a subclade containing other Zschokkella species parasitizing the gall bladder of brackish and marine fish hosts, located within the coelozoic clade of the major freshwater clade; this supports the existence of a marine subclade within the 'freshwater' clade, as well as the existence of a correlation between tissue tropism and myxosporean phylogeny.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12