Ultrastructure, development, and host–parasite relationship of a new species of the genus Pleistophora—a microsporidian parasite of the marine fish Epinephelus chlorostignei

Abstract

The life cycle of a new microsporidian of the genus Pleistophora is described. This parasite infects the epithelial cells of the gut and the peritoneal cavity of the Red Sea fish, Epinephelus chlorostignei. All stages develop within a special structure, the sporophorocyst, which is covered by a thick dense wall. This wall grows along with the growth of the parasites inside. Meronts are uni- to binucleate, which divide and constantly give rise to sporonts. During transition to sporonts, the cell border of the meronts increases its thickness, temporarily featuring thick irregular projections. Eventually, a uniform thick sporont wall is formed; then, the sporont cells detach themselves from the wall (future wall of the sporophorous vesicle, SPV) and start a series of divisions to produce sporoblasts. The SPV wall is compact, has no pores, and consists of two layers. Mature spores measure about 2.0 x 1.8 microm. They possess a polar filament with 20-28 coils, a posterior vacuole, and a polaroplast made up of an outer part of dense and closely spaced lamellae encircling an inner part of widely spaced lamellae. All morphological and ultrastructural features indicate that the described microsporidian parasite belongs to the genus Pleistophora.

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

“…Similar observations have been recorded previously (Canning 1976;Maurand et al 1988;Weissenberg 1976;Lom et al 1993;Matos et al 2005;Kent and Speare 2005;Lom and Dyková 2005;Lovy et al 2007;Casal et al 2008;Abdel-Ghaffar et al 2009Stephens 2009); these authors stated that in fish, a type of host-parasite relationship occurs when microsporidia induce the development of xenomas. Muscle tissue turns opaque and cloudy in affected fish, appearing granular and unappetizing for anglers (Lom et al 2000a, b, c;Sutherland et al 2000;Lom 2002;Sutherland 2002;Sutherland 2002;Sutherland et al 2004).…”

Ultrastructural and Molecular Characterisation of an Heterosporis-Like Microsporidian in Australian Sea Snakes (Hydrophiinae)

“…Pleistophora spp. have been found in ‘cysts’ in the muscles of fish [ 55 , 70 ] and species such as Pleistophora hyphessobryconis show broad host specificity and affect a range of freshwater fish species [ 55 ]. The microspores formed by several piscine Pleistophora spp.…”

Morphological and ultrastructural description of Pleistophora dammami sp. n. infecting the intestinal wall of Saurida undosquamis from the Arabian Gulf, Saudi Arabia

“…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). The characteristic features of the genus Pleistophora, as proposed by Lom and Dyková (2005), were as follows:…”

“…Fishes are hosts to 156 recorded species of microsporidia assigned to 14 genera (Lom and Nilsen 2003). The generic and specific differentiation of these parasites is entirely based on ultrastructural characteristics (Canning and Lom 1986;Abdel-Ghaffar et al 2009). …”

“…This genus was originally established for a species described from fish muscles (Wilson 1984;Lom and Nilsen 2003;Abdel-Ghaffar et al 2009). 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.…”