PARENT SESSION

2C - Biomarkers
Poster Hall
8:30 AM - Tuesday, 29 April 2003
Chair: Hansen, P.D.¹, ¹
Co-chair: Vindimian, E.², ²

(TUP/95) Role of digestive gland cells in adaptation to chronic pollution in slugs: A transplant study.

Zaldibar, Benat ¹, Cancio, Ibon¹, Marigómez, Ionan¹, ¹ Basque Country University., Bilbo, Basque Country, Spain

ABSTRACT- The digestive gland epithelium is composed of three cell-types in slugs, Arion ater: digestive (DC), excretory (EC) and calcium cells (CC). Usually DC outnumber CC and EC, but under chronic metal pollution cell-type replacement occur and EC become dominant. Presently, slugs from an abandoned Zn mine were transferred to a non-polluted area, and the other way around for 3 and 10 days. Tissue metal levels were determined by autometallography (AMG) and Atomic Absortion Spectrophotometry (AAS). AMG deposits were localized in the basal laminae of digestive alveoli in slugs collected from the non-polluted site and in EC in slugs inhabiting the mine area. Ten days after transplantation to the polluted site AMG deposits ocurred in basal laminae and EC whereas the distribution of metals in digestive gland remained unchanged after 10 days transfer to the clean site, in agreement with AAS data. Further, digestive gland was histologically processed to quantify the volume density (Vv) of each cell-type. Slugs from the polluted site presented lower Vv (DC) than those from the clean site. Hyperplasia of CC was recorded in slugs collected from the mine. Ultrastructural and histochemical analysis were performed to characterise the three cell-types in slugs adapted to metal chronic pollution. After transfer to the clean site Vv (EC) decreased transiently to recover original levels after 10 days. By contrast, transplant from the clean to the polluted site resulted in a prompt increase in Vv(EC) already after 3 days. It seems that recovery of epithelial integrity after chronic pollution takes longer than the time needed by metal pollution to elicit cell-type replacement in slugs coming from non-polluted sites. Funded by Basque Government (PI/GV99-23).

Key words: cell-type replacement, slugs, chronic pollution, metal