Some aspects of catalase induction in baker's yeast (Saccharomyces cerevisiae)

Abstract

Yeasts grown in anaerobic liquid media produced catalase in response to the presence of H,O s in the growth medium. The fact that some of the induced enzyme was active at the cell surface, bound either to the cell wall or cell-surface membrane, eliminated the need to crush cells in order to release the enzyme complement. Instead, catalase production was moni tored by using H,0,-reagent strips to detect changes in the level of H a O, in the growth medium. In addi tion, catalase induction in yeasts was found to be temperature-sensitive.It is suggested that biology teachers in schools might find the following experiments useful for demonstrat ing essential features of substrate-induced enzyme synthesis, based on the Jacob-Monod model, and for showing that the activity of certain genes can be modified by environmental temperature.

Some experiments with respiratory deficient mutants of yeast (iSaccharomyces cerevisiae)

“…These results, and those from other classroom experiments with yeast, add weight to the view previously expressed in this journal (Freeland, 1971(Freeland, , 1973(Freeland, , and 1974Cusimano, 1976), that yeast is not only a convenient, safe, and inexpensive micro-organism for schools to handle, but also that experiments with this organism are invaluable for illustrating broader biological principles, such as those of population growth, enzyme induction, enzyme kinetics, industrial fermentation, and mutation.…”

Some uses of tissue expiants in the teaching of protein synthesis

“…Freeland (1974) has described a method for the study of catalase induction in Saccharomyces cerevisiae which may be used by students in a quantitative study of enzyme induction. The use of plant tissue expiants derived from the storage organs of higher plants offers a simple system which can be used to demonstrate some processes which underlie protein synthesis and also cell differentiation in more complex systems.…”