First ultrastructural data on the human tapeworm Taenia asiatica eggs by scanning and transmission electron microscopy (SEM, TEM).
Humans are definitive hosts of three species of the Taenia genus, namely Taenia solium, Taenia saginata and Taenia asiatica. The relative novelty of the latter explains the lack of knowledge concerning certain relevant aspects related to this parasite, such as its definite geographical distribution and whether its eggs can infect humans or not. So far, only the eggs of T. solium are known to be infective for humans, producing cysticercosis. Although eggs contain the infective stage, the oncosphere, there is a lack of research on the ultrastructure of eggs of human taeniids. We show, for the first time, the ultrastructure of eggs of T. asiatica by means of SEM and TEM analyses. We detected all the envelopes, namely the egg shell, vitelline layer, outer embryophoric membrane, embryophore, granular layer, basal membrane, oncospheral membrane and oncospheral tegument. Hooks surrounded by myofibrils and glycogen-like particles, the two types of secretory granules of the penetration glands, as well as several nuclei and mitochondria were also revealed in the oncospheres. In addition to the already known structures in eggs from other Taenia species, the presence of two types of small vesicles is described herein, possibly corresponding to exosomes and ectosomes because of their shape and size, which could participate in the host/parasite intercellular communication.
Department of Cellular Biology and Parasitology, Faculty of Pharmacy, University of Valencia, Burjassot, Valencia, Spain. mteresa.galan@uv.es.
M Teresa
MT
Galán-Puchades
Autonomous Region Center for Disease Prevention and Control, Nanning, Guangxi, China.
Yichao
Y
Yang
Department of Cellular Biology and Parasitology, Faculty of Pharmacy, University of Valencia, Burjassot, Valencia, Spain.|Joint Research Unit on Endocrinology, Nutrition and Clinical Dietetics, University of Valencia-Health Research Institute La Fe, Valencia, Spain.
Antonio
A
Marcilla
Department of Parasitology and Parasite Resource Bank, School of Medicine, Chungbuk National University, Cheongju, South Korea.
Seongjun
S
Choe
Department of Parasitology and Parasite Resource Bank, School of Medicine, Chungbuk National University, Cheongju, South Korea.
Hansol
H
Park
Laboratory of Biochemistry and Molecular Parasitology, Institute of Biotechnology, University of Granada, Granada, Spain.
Antonio
A
Osuna
Department of Parasitology and Parasite Resource Bank, School of Medicine, Chungbuk National University, Cheongju, South Korea.
Keeseon S
KS
Eom
D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000648:ultrastructure; D010063:Ovum / Q000648:ultrastructure*; D013621:Taenia / Q000648:ultrastructure*; D013622:Taeniasis / Q000469:parasitology
Eggs; Embryophoric envelopes; Extracellular vesicles; Oncosphere; Taenia asiatica; Ultrastructure