Morphological and molecular biological characterization of Pleistophora aegyptiaca sp. nov. infecting the Red Sea fish Saurida tumbil

Abstract

One hundred three out of 225 (45.8%) of the Red Sea fish Saurida tumbil were infected with microsporidian parasites. The infection was recorded as tumor-like masses (whitish macroscopic cysts) or xenomas often up to 2 cm in diameter and embedded in the peritoneal cavity. Generally, the infection was increased during winter 63.8% (86 out of 135) and fall to 18.9% (17 out of 90) in summer. Light microscopic study revealed that xenomas were encapsulated by a fibrous layer encircling numerous sporophorous vesicles filled with mature spores measuring 1.7 ± 0.6 (1.5-2.7 μm) × 1.5 ± 0.3 μm (1.2-1.8 μm) in size. Ultrastructural microscopic study showed the presence of smooth membranes of the sarcoplasmic reticulum forming a thick, amorphous coat surrounding various developmental stages of the parasite. The various recognizable stages of the parasite were uninuclear, binucleated, and multinucleated meronts followed by detachment of the plasmalemma of the sporont from the sporophorous vesicle producing sporoblasts. Mature spores consist of a spore coat and spore contents. The spore contents consist of the uninucleated sporoplasm and a posterior vacuole located at the posterior end. The polar tube consists of a straight shaft and a coiled region (26-32 coils) arranged in many rows along the inside periphery of the spore. The polaroplast consisted of an anterior region of closely and loosely packed membranes. Molecular analysis based on the small subunit rDNA gene was performed to determine the phylogenetic position of the present species. The percentage identity between this species and a range of other microsporidia predominantly from aquatic hosts demonstrated a high degree of similarity (>92%) with eight Pleistophora species. Comparison of the nucleotide sequences and divergence showed that the sequence of the present microsporidium was most similar to that of Pleistophora anguillarum (99.8% identity) differing in 13 nucleotide positions. So, the present species was recorded and phylogenetically positioned as a new species of Pleistophora.

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).…”

“…Ultrastructurally, Pleistophora is, with the exception of a few rare species, typically characterized by a lack of xenoma formation, nuclei that are unpaired at all stages of development and meronts that are variably shaped plasmodia, dividing by plasmotomy. External to the plasma membrane of the meronts there is a thick amorphous wall, which divides along with the meronts during merogony, and then again during sporogony, to become polysporoblastic within a parasitophorous vacuole bound with membrane derived from the host cell (Pekkarinen 1996;Lom 2002;Abdel-Ghaffar et al 2012). A large number of spores are produced within sporophorous vesicles, with macro-and microspores arising from sporogonial plasmodia of different sizes.…”

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

“…Similar to the host of Glugea nagelia, E. awoara also belongs to the family Serranidae, but several studies state that Microsporidia lack strict host specificity (Lom and Dyková 1992, Lom et al 1995, Nagasawa and Cruz-Lacierda 2004, Payghan et al 2009. There are currently only three other microsporidians described from the Red Sea: Pleistophora aegyptiaca, P. pagri Morsy, Abdel-Ghaffar, Mehlhorn, Bashtar et Abdel-Gaber, 2012 (JF797622) and Microsporidium aurata (KF022044) (see Abdel-Ghaffar et al 2012. The sequences of the last two species were not included in molecular and phylogenetic analysis because they are very short, only 249 bp and 538 bp long, respectively, and they presented a low score according to BLAST homology.…”

“…Research on these parasites is restricted to the description of just three species from the entire extent of the Red Sea coastline, all of which were described from Egypt. These species are Pleistophora pagri Morsy, Abdel-Ghaffar, Mehlhorn, Bashtar, Abdel-Gaber, 2012 from Pagrus pagrus Linnaeus, Pleistophora aegyptiaca Abdel-Ghaffar, Bashtar, Morsy, Mehlhorn, Al Quraishy, Al-Rasheid, Abdel-Gaber, 2012 from Saurida tumbil Bloch and Microsporidium aurata Morsy, Bashtar, Abdel-Ghaffar, Al-Quraishy, 2013 from Sparus aurata Linnaeus (see Abdel-Ghaffar et al 2012.This paper thus represents the first report of the occurrence of a microsporidian infecting fish in the Red Sea outside of Egypt. Using ultrastructural and molecular data, a new Glugea is described.…”

Microsporidians xenomas of anglerfish from NE Atlantic waters

“…Classification of microsporidia parasites is usually made on the basis of ultrastructural characters including size and morphology of spores, number of coils of the polar tube, developmental life cycle and hostparasite relationship (Sprague et al 1992). Nevertheless, the use of molecular data has become indispensable to achieve an accurate identification of these parasites, due to the difficulty of establishing a diagnosis through ultrastructural studies when there is not a key ultrastructural feature (M€ uller et al 1999;Abdel-Ghaffar et al 2012;Morsy et al 2012).…”