A proteome study of Myxobolus episquamalis parasite of flathead mullet (Mugil cephalus Linné 1758) of Senegalese coasts

Résumé

Abstract

Myxozoa are endoparasites characterized by a simple cytoplasmic organization and multicellular spores containing polar capsules with extrusible polar filaments. Myxozoans have a complex life-cycle, typically alternating between teleost fish and invertebrate hosts, in which are formed myxospores and actinospores respectively. Both of these spores contain polar capsules, which are strikingly similar in their morphogenesis and mature structure to the nematocysts found in the phylum Cnidaria. Similarity with cnidarians was also supported by several phygenetic molecular studies. In this context, we have performed the first large scale proteomic study of a Myxozoa, Myxobolus episquamalis which is a parasite of flathead mullet in Senegal. Comparisons with different databases combining different softwares confirm importance of cytoskeleton and central metabolism in the invasion process. Our study identified for the first time neuropeptides and analgesic toxins encoded by the M. episquamalis. It also highlighted long peptides presenting strong homologies with proteins of unknown function, a large fraction of them being identified from Nematostella vectensis proteome. Homologies with other lower Bilateria raise again the question of the position of Myxozoa at the transition between Cnidaria and Bilateria.

Keywords: Myxozoa, M. episquamalis, Proteomics, Phmmer, Neuropeptide.