Putative symbiotic elements during post-hatching development of the midgut gland (MGG) in Pomacea canaliculata"

KOCH E.; VEGA, I.A.; ALBRECHT, E.A.; GAMARRA-LUQUES, C.; CASTRO-VAZQUEZ.

San Luis, Argentina

Congreso; XIX Reunión Científica Anual de la Sociedad de Biología de Cuyo.; 2001

Sociedad de Biología de Cuyo.

Several lines of evidence have suggested the symbiotic nature of intracellular corpuscles in the MGG of adult snails. Pre- and post-hatching development of the MGG was studied in search of the origin of these corpuscles. Before hatching, the MGG originates as an albumen- filled pouch, lined by a flattened unicellular epithelium. A layer of columnar cells, intermingled with clear pyramidal cells, eventually develops at one side of the pouch. The columnar cells incorporate albumen globules by endocytosis. Later, alveoli fo rmed by both cell types develop at one side of the pouch, between the epithelium lining the albumen core and the external, flattened epithelium. Symbiotic type C corpuscles can be already found within alveolar cylindrical cells 3-5 days post-hatching.