Effect of nitrogen limitation and sporulation on sterol and lipid formation in Saccharomyces cerevisiae.

The content of sterols and lipids was compared in the cells of Saccharomyces cerevisiae cultivated in sporulation and the sterol-induction nitrogen-limited media. After 24 h the measured values in the two cultivations did not significantly differ. However, after subsequent 24 h, further formation of lipid globules and a corresponding increase of lipid and sterol content was detected only in the sterol-induction medium. To demonstrate the similarity of physiological state during the first day of the two cultivations, the combined cultivations were performed. Maximum sporulation, suggesting maximum similarity, of the two processes was achieved when the cells were grown in the sterol-induction medium for 15 h and then transferred to a sporulation medium.

Immunological changes after long-term feeding of germfree piglets with protein isolates and yeast cell walls from Candida utilis as food additives.

Germfree piglets were fed a diet supplemented with cell walls and a protein isolate from Candida utilis for 54 days. Besides morphological signs of activation of the lymphoid tissue which occurred primarily in the intestine of piglets which had been fed yeast cell walls, even an increased serum immunoglobulin level could be detected. In sera and intestinal content of piglets fed both with cell walls and isolated protein, specific antibodies capable of agglutinating yeasts were present. Even though a limited number of experimental animals was employed it can be concluded that the yeast material added to the diet elicited an immune response.