| Abstract: | The optimal conditions for preparing protoplasts with high yields by using the cells of two (low and high potent) isogenic cyclosporine-producing Tolypocladium strains were developed. A specific medium containing 0.5 per cent yeast autolysate (by dry weight) and 3 per cent glucose was used. When grown on this medium the cells of the highly potent strain 847 acquired a yeast-like shape. High yields of protoplasts prepared from the low potent strain 43 mycelium were obtained via prior incubation with 0.01 M dithiothreitol followed by treatment with a complex of enzymes from Helix pomatia for 1.5 to 2 hours was used. For preparation of the protoplasts with employing the highly potent strain 847 cells the prior incubation with dithiothreitol was not required, but it was necessary to employ a mixture of the enzyme complex (Helix pomatia), drizilase (Irpex lacteus) and chitinase (Streptomyces griseus) for 18 hours. The electron microscopic data on the two isogenic strains and their protoplasts are presented. The protoplasts proved to be a suitable initial material for investigating bioenergetic processes at the subcellular level and further genetic improvement of the strains. |
