Protistology 10 (3) 67–78 (2016) |
Perezia nelsoni (Microsporidia) in Agmasoma penaei-infected Atlantic white shrimp Litopenaeus setiferus (Paenaidae, Decapoda) and phylogenetic analysis of Perezia spp. complex |
1 Department of Comparative Biological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge LA, USA
| Submitted: September 14, 2016 | Accepted: September 31, 2016 | Summary During the years 2012-2014 samples of Atlantic white shrimp Litopenaeus setiferus collected offshore near Plaquemines Parish, Louisiana (USA) were submitted to the Louisiana Aquatic Diagnostic Laboratory with gtumor likeh lesions in the exoskeleton and internal organs. Light (LM) and electron microscopy (EM) examination indicated that 19 shrimp were infected with the microsporidium Agmasoma penaei (=Thelohania penaei Sprague, 1950, n. comb. Hazard and Oldacre, 1975). The Louisiana isolate of A. penaei was morphologically and genetically characterized previously (Sokolova et al., 2015). In 15 of 19 shrimp the infection was limited to subcutaneous and ovarian tissue, and in 4 shrimp musculature also seemed to be affected looking unusually whitish and/or opaque. According to our observations, A. penaei did not occur in muscle tissue, however, records on tissue tropism of A. penaei obtained by earlier authors, occasionally included skeletal muscles. Upon examination of skeletal muscles of these 4 shrimp by LM we found out that the tissue contained microsporidia-like individual spores of much smaller (2.0 × 1.1µm) size, than those of A. penaei. Electron microscopy and molecular analysis indicated that L. setiferus was co-infected by another microsporidium, structurally and genetically similar to Perezia nelsoni Sprague 1950 from the Mississippi coast of the Gulf of Mexico (Cheney et al., 2000; Canning et al., 2002; Genebank reference: "Pleistophora sp. LS" Accession # AJ252959). Persistent co-infection of white shrimp with two microsporidia with different tissue tropism reported herein, suggests that infection of muscles previously attributed to A. penaei, might be due to the overlooked P. nelsoni. The paper describes fine morphology and phylogenetic relations of P. nelsoni from a new location. The novel SSUrDNA sequence was deposited in Genebank, under accession number KX85642.
Key words: Microsporidia, Decapoda, Perezia nelsoni, Agmasoma penaei, Litopenaeus setiferus, Louisiana,
electron microscopy, molecular taxonomy
Address for correspondence: Yuliya Sokolova. Microscopy Center, Department of Comparative Biological Sciences, School of Veterinary Medicine, Louisiana State University, 1909 Skip Bertman Drive, Baton Rouge LA, 70803; e-mail: yysokolova@gmail.com |
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