Further studies on the subcellular distribution of Cd2+ in Cd-sensitive and Cd-resistant strains of Saccharomyces cerevisiae.

When a Cd-resistant strain (301 N) and a Cd-sensitive strain (101 N) of Saccharomyces cerevisiae were incubated in medium containing Cd2+, a large proportion of the cellular Cd2+ was found in the cytosol of strain 301 N, but not in that of strain 101 N. Approximately 65% of the cellular Cd2+ was released from strain 301 N after treatment with chitosan, which affects cell membrane permeability. About 80% of the cellular Cd2+ released from strain 301 N by chitosan treatment was detected in a 30 000-10 000 molecular weight fraction prepared by ultrafiltration. The distribution of Cd2+ into the cytosol in strain 301 N was inhibited in the presence of cycloheximide. The proportion of cellular Cu2+ or Zn2+ present in the cytosol after incubation with these ions was similar for the two strains (about 40%).