Eudiplozoon nipponicum: host-parasite interactions in blood-feeding diplozoids
|Fakulta / Pracoviště MU
|Eudiplozoon nipponicum (Monogenea) is a blood-feeding parasite from the gills of carp, which due to its unique biological properties, represents an ideal model for studies on diverse biological interactions. Parasite's developmental stages (oncomiracidium, diporpa, juvenile, adult) were investigated using combined microscopic approach to identify explicit adaptations to the ectoparasitic life. Diplozoids have evolved a complex mechanism dedicated to attachment to the host and localization on host body that is advantageous for feeding and reproduction. The main attachment system comprises prominent buccal suckers at the ventral site of the parasite's forebody along with the two well-developed muscular haptors, each with four pairs of clamps in two rows and two central hooks, located on the hindbody. Complicated structure of parasite's tegument, including folds and lobular extensions in the middle part of hindbody, supports its firm fixation to the host gills by locking to the gill lamellae. The complex digestive tract is well-equipped for the hematophagous feeding and consists of a mouth opening, eversible pharynx with adjacent glandular structures and a blind-ending gut with caecal lining. The buccal suckers seem to assist in the parasite’s translocation while searching for an optimal niche and we speculate about their temporary attachment function during feeding as well. They appear to be located in a buccal capsule and probably evert when needed (e.g. while feeding). Structures of unknown function, so called the glandulo-muscular organs, which are located apically and opened into the mouth corner, are considered to be a part of digestive tract. These structures seem to be specific for this species. The possibility of extracorporeal digestion of this parasite is discussed.