Effect of sublethal doses of cadmium, inorganic mercury and methylmercury on the cell morphology of an insect cell line (Aedes albopictus, C6/36).

The effect of CdCl2 (44 microM), HgCl2 (3.7 microM), and MeHgCl (2 microM) on the morphology of Aedes albopictus C6/36 cells was studied at the light microscopical level. Treatment times and metal concentrations were in the sublethal range as determined by a fluorometric dye exclusion test. The three metal species had profound effects on the cell morphology. MeHgCl treatment induced the development of a large number of short, actin-supported, tangled filopodia. Both CdCl2 and HgCl2 induced long extensions. Pretreatment with colchicine but not with cytochalasin B prevented formation of these extensions which suggests that they were supported by microtubules. This was confirmed by immunostaining for microtubules. The extensions were relatively stable towards colchicine post-treatment. To authors' knowledge, this effect has not yet been described for heavy metals. The similarity with 20-hydroxyecdysone-treated cells and the occurrence of cytoplasmic feet in insect cells is discussed.