Subcellular localization of zinc in experimentally polluted tubifex tubifex (Annelida, Oligochaeta)

Abstract 1. 1. Localization of Zn (+ 65 Zn) has been examined within twelve subcellular fractions (derived from discontinuous sucrose gradients) of preincubated T. tubifex . 2. 2. Zn was principally associated with the pellet (28% of total) and lowest density fraction (14%). 3. 3. Pellet ultrastructure is composed of chloragosomes and epicuticle. Pellet Zn is localized within chloragosomes, X-ray microanalysis showing chloragosomal Zn concentration to exceed epiculticular Zn by a factor of thirty. 4. 4. Biochemical and ultrastructural studies demonstrate that Zn is not appreciably bound to other cell constituents. 5. 5. Chloragosomal localization of internalized Zn indicates a capacity for detoxification.