VANADIUM AFFECTS VACUOLATION AND PHOSPHATE-METABOLISM IN HANSENULA-POLYMORPHA

The yeast Hansenula polymorpha is able to grow on vanadate concentrati ons that are toxic to other organisms. Transmission electron microscop y analysis showed that H. polymorpha cells growing on a vanadate-conta ining medium undergo a significant increase in cell vacuolation and a thickening of the cell wall; the presence of small cytoplasmic vesicle s and an increase in cristae al the level of the plasma membrane were also observed. These ultrastructural modifications were accompanied by a change in the intracellular polyphosphate level, as shown by in viv o P-31-NMR. The involvement of these observed changes in vanadium deto xification is discussed.