SPHEROPLASTS OF THE YEAST CANDIDA UTILIS

Abstract

Svihla , G. (Argonne National Laboratory, Argonne, Ill.), F. Schlenk, and J. L. Dainko . Spheroplasts of the yeast Candida utilis . J. Bacteriol. 82: 808–814. 1961.—The formation and properties of spheroplasts of the yeast Candida utilis , produced by digestion of the cell walls with snail gut juice ( Helix pomatia ) in isotonic medium, were studied by phase, interference, and ultraviolet microscopy, and tracer techniques. Cells cultivated in the presence of l -methionine, S-methyl- l -methionine, and l -homocysteine (5 μmoles/ml) were more susceptible to enzyme action than ordinary cells. These cells contain increased amounts of S-adenosylmethionine in the vacuole which facilitates ultraviolet microscopy. Spheroplasts are stable in 0.6 m KCl containing 0.04 m phosphate, but are disintegrated by water, sonic vibration, or ultraviolet irradiation. Exposure in isotonic medium to 6 × 10 4 erg/mm 2 energy at 253 mμ breaks the cytoplasmic membrane and liberates the vacuole with membrane intact. The vacuolar membrane may be broken with about three times the initial dose of ultraviolet.