Variation des stérols chez Kluyveromyces lactis et chez un mutant résistant par culture en présence de doses sublétales d'amphotéricine B

A mutant strain of Kluyveromyces lactis resistant to amphothericin B and weakly to nystatin has been isolated from subcultures of the wild strain grown in the presence of sublethal doses of amphothericin B. The mutant and the wild strain were equally sensitive to pimaricin, filipin, and candicidin. The efficacy of fungizone was very low. In comparison with the wild strain the level of sterols was two times lower in the resistant strain but the composition of these sterols was about the same in the two strains. The action of sublethal doses of amphothericin B on the composition of the sterols was the same in these two yeasts and brought a 40% decrease of the total sterol level and a modification in their distribution. This variation cannot fully explain the resistance of the yeast but it may be associated to other changes of the membranes. [Journal translation]