SPHEROPLASTS OF THE YEASTCANDIDA UTILIS

Abstract

and properties of spheroplasts of the yeast Candida utilis, produced by digestion of the cell walls with snail gut juice (Helix pomnatia) in isotonic medium, were studied by l)hase, interference, and ultraviolet microscopy, and tracer

Pretreatment of Cell Suspensions as a Method to Increase the Protoplast Yield of Haplopappus gracilis

“…An increased yield of protoplasts was also obtained from cells grown in media supplemented with sulfur amino acids or other sulfhydryl compounds. Similar results have earlier been obtained with fungi after the addition of sulfur amino acids (Killick 1971, Svilha et al, 1961 and mercaptoethanol (Duell et al, 1964) to the culture medium. Since both the sulfur amino acids methionine and cysteine and other sulfhydryl compounds showed a great positive effect on •protoplast yield but other amino acids and reducing agents without sulfhydryl groups were less effective or inactive, it seems likely that the sulfhydryl group are responsible for the positive effects.…”

Modification of the Composition and Structure of the Yeast Cell Wall by Culture in the Presence of Sulfur Amino Acids

“…The importance of the strain, growth conditions, and the physiological state of the harvested cells in determining the sensitivity of yeast cells to the digestive enzymes has also been emphasized (25). Svihla et al (23) reported that Candida utilis cultured in a medium supplemented with sulfur amino acids formed spheroplasts by the enzymatic action of snail extract more readily than nonsupplemented cultures. The sulfonium compound, S-adenosylmethionine (AM) occurred in concentrations ranging from 0.3 to 2.0 umoles per g (wet weight) of nonsupplemented yeast cells (23).…”

“…Svihla et al (23) reported that Candida utilis cultured in a medium supplemented with sulfur amino acids formed spheroplasts by the enzymatic action of snail extract more readily than nonsupplemented cultures. The sulfonium compound, S-adenosylmethionine (AM) occurred in concentrations ranging from 0.3 to 2.0 umoles per g (wet weight) of nonsupplemented yeast cells (23). In the sulfur amino acid-supplemented medium, however, the AM concentration was elevated to 20 to 30 ,umoles per g (wet weight) of cells.…”

“…In the sulfur amino acid-supplemented medium, however, the AM concentration was elevated to 20 to 30 ,umoles per g (wet weight) of cells. It was proposed that, during growth, the structure and composition of the cell wall were altered as an indirect consequence of excessive AM synthesis (23).…”

“…71251, 250 mg of solids/ml) were used to convert intact yeast cells to spheroplasts. The formation of spheroplasts was followed by phase-contrast microscopy and measurement of the release of cytoplasmic constitutents absorbing at 260 nm after bursting of samples of the spheroplasts by dilution into distilled water (23).…”