0 mg (Control). HORMESIS IN YEAST. Cao Tian Qin, Tham Shi Yuan, Lim Yuan Wei. Exposure of yeast to other stressor agents, e.g. antibiotics. Hwa Chong Institution. ABSTRACT. OBJECTIVES. INTRODUCTION.
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HORMESIS IN YEAST
Cao Tian Qin, Tham Shi Yuan, Lim Yuan Wei
Hwa Chong Institution
This project investigates the phenomenon of hormesis in the yeast, Saccharomycescerevisiae. The principle of hormesis applies to the stimulation of growth in the presence of low dosage of stressor agents. High concentrations of Paracetamol and Traditional Chinese Medicine, Angelica sinensis, were shown to inhibit growth of yeast. However, at low concentrations, growth of yeast was stimulated in the presence of Paracetamol and TCM and a mixture of both. This was carried out by growing the yeast in broth cultures supplemented with varying concentrations of Paracetamol or TCM, serially diluting the yeast cultures and plating on potato dextrose medium. The number of colonies was then determined. Polyacrylamide gel electrophoresis analysis indicated an alteration in the expression of genes, leading to new proteins synthesized in the presence of low dosages of stressor agents. These findings can be applied commercially in which yeast growing in fermenters in the production of beer can be stimulated with such stressor agents, thus increasing the yield.
Extraction of proteins from yeast
Growth of yeast with Paracetamol and TCM
Preparation of Paracetamol and TCM
Preculture of yeast
Effect of high concentration of Paracetamol and TCM on growth of yeast
Hormetic effect of Paracetamol on growth of yeast
0 mg (control)
At a high amount (300 mg) of Paracetamol and TCM, inhibition of yeast growth was observed. Both are stressor agents.
Yeast growth was stimulated the most when 3 mg Paracetamol added to 30 ml PD broth.
Hormetic effect of TCM on growth of yeast
Effect of Paracetamol on protein synthesis in yeast
Marker 0 3 15 30 60 150 300 450 mg
3 mg TCM
CONCLUSION & DISCUSSION
Yeast growth was stimulated when 3, 15 and 30 mg added to 30 ml PD broth.
Hormetic effect of mixture on growth of yeast
15 mg TCM
30 mg TCM
The mixture of stimulated growth of yeast at all concentrations tested significantly (t-test p value < 0.05).
Stimulation of growth by 30 mg of mixture of Paracetamol and TCM was the highest (4.01 x above control).
Mrs Goh-Yip Cheng Wai, project mentor
Mdm Lim Cheng Fui, Science Research Centre,
Hwa Chong Institution