Use of snail enzyme for the selection of glucose-and mannose-negative mutants in Saccharomyces cerevisiae.

The relationship between growth and sensitivity of Saccharomyces cerevisiae cells to snail enzyme led us to work out the conditions for using this enzyme to isolate mannose-negative and glucose-negative mutants. The technique is based on a prior growth on a glycerol medium in which any cell becomes resistant to snail enzyme, followed by a period of growth in a medium in which only the wild-type cells can grow, thereby becoming sensitive to the enzyme. This technique was very effective in both tested cases. This result suggests that the method described might also be applied to isolate other kinds of mutant.