IBBEA   24401
INSTITUTO DE BIODIVERSIDAD Y BIOLOGIA EXPERIMENTAL Y APLICADA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Scolex ultrastructure and histochemistry of the scolex glands of Monticellia magna and Proteocephalus pimelodi (Cestoda: Onchoproteocephalidea)
Autor/es:
IVANOV VERÓNICA A.; ARREDONDO NATHALIA J.; MUTTI, LEONARDO
Lugar:
Buenos Aires
Reunión:
Jornada; VIII Jornadas de Jovenes Investigadores; 2018
Institución organizadora:
Facultad de Ciencias Veterinarias, Universidad de Buenos Aires
Resumen:
Onchoproteocephalidean cestodes are parasites of elasmobranchs, freshwater fishes, amphibians, reptiles and marsupials. In South America, they are mostly found in Siluriformes (Teleostei), mainly in Pimelodidae. The scolex of the tapeworms is the principal attachment organ used to keep their position on the intestinal wall of their hosts. In most onchoproteocephalideans, the scolex is composed of four suckers and usually presents glands. In addition, the tegumental surface of the scolex and strobila is covered by microtriches, which add to the adhesion to the intestinal wall. The objective of the present study was to describe the internal ultrastructure of the scolex microtriches, and the histochemical composition of the apical glands in 2 onchoproteocephalideans. Six scolices of Monticellia magna and five scolices of Proteocephalus pimelodi, were fixed in 4% hot formalin, and stained with Coomassie brilliant blue, Alcian blue, Toluidine blue, and periodic acid-Schiff (PAS). Additionally, specimens of M. magna and P. pimelodi were observed with transmission electron microscopy. All worms were collected from catfishes (Pimelodus spp.). As a result, two types of glands were observed in the apex and around the suckers. Both differ in their secretion mechanism, and in the size of the secretion granules. Furthermore, groups of PAS positive cells were noticed around the suckers, in the apex, and in the neck, in the same area as the glands. Based on these results, it is conceivable that these groups of PAS+ cells might be related to several glands described mostly on the scolex apex, but evidently widely distributed on most surfaces of the scolex. Their mucopolysaccharide secretion might be involved in the adhesion to the intestinal mucosa of the catfishes. The microthrix pattern includes gladiate spinitriches and capilliform filitriches with large caps (ratio cap:base 1:0,25-0,74). Which might be involved in the attachment to the intestinal mucosa of the host. Finally, the internal structure of the scolex is described for the first time in South American onchoproteocephalid tapeworms.