Distribution of Copper in a Highly Copper-tolerant Yeast Observed Using Analytical Electron Microscopy

Katsuyuki Uematsu, Akira Inoue, Fumiyoshi Abe, Takeshi Miura and Koki Horikoshi

Abstract: In order to analyze the defensive mechanisms against high concentrations of CuSO₄ in the copper-tolerant yeast, Cryptococcus liquefaciens (N6 strain), morphology analysis and analytical electron microscopy were conducted on. Copper was detected in strain N6. Copper was distributed in the cytoplasm, rather than in small vacuoles. These results suggest that cytoplasmic and/or some other proteins with a high affinity to heavy metals, may have a role in the defensive mechanisms against high concentrations of CuSO₄, as a chelator, in the N6 strain.

Key words: copper-tolerant yeast, EDS, electron spectroscopic imaging, elemental mapping