Simple and sensitive procedure for screening yeast mutants that lyse at nonpermissive temperatures

Area of Science:

• Biochemistry
• Microbiology
• Molecular Biology

Background:

• Alkaline phosphatase is an enzyme crucial in various cellular processes.
• Detecting enzyme activity is vital for understanding gene function and cellular stress responses.

Purpose of the Study:

• To establish a straightforward method for screening yeast mutants based on alkaline phosphatase activity.
• To visualize and quantify alkaline phosphatase liberation from yeast cells post-mutagenesis.

Main Methods:

• Yeast cells undergo mutagenesis and are cultured on agar plates at 25°C.
• Cells are subsequently incubated at 37°C to induce stress.
• Plates are overlaid with p-nitrophenylphosphate substrate at pH 9.7.

Main Results:

• Lysed yeast cells release alkaline phosphatase into the surrounding agar.
• The enzymatic hydrolysis of p-nitrophenylphosphate produces a distinct yellow color.
• The intensity and localization of the yellow color correlate with enzyme activity.

Conclusions:

• This method provides a simple, visual assay for alkaline phosphatase activity in yeast.
• The assay is effective for screening mutagenized yeast populations.
• It facilitates the identification of yeast strains with altered alkaline phosphatase levels.