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Hormesis in Yeast

Hormesis in Yeast. Cao Tian Qin 4S104 Tham Shi Yuan 4S128 Lim Yuan Wei 4S308. Contents. Brief introduction on rationale of project Brief literature review Objectives and hypotheses Independent, dependent and controlled variables Materials and methodology Data analysis

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Hormesis in Yeast

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  1. Hormesis in Yeast Cao Tian Qin 4S104 Tham Shi Yuan 4S128 Lim Yuan Wei 4S308

  2. Contents • Brief introduction on rationale of project • Brief literature review • Objectives and hypotheses • Independent, dependent and controlled variables • Materials and methodology • Data analysis • Application of project • References

  3. Introduction • Uses of the yeast, Saccharomycescerevisiae

  4. Introduction - Hormesis • 1888 - German pharmacologist Hugo Schulz observed that the growth of yeast could be stimulated by small doses of poisons • Poisons are actually stressor agents

  5. Introduction - Hormesis

  6. Introduction - Hormesis • Certain stressor agents have been known to stimulate at low doses but inhibit at high doses e.g. antibiotics, aspirin, radiation • Principle of hormesis is not well-studied in yeast

  7. Objectives

  8. Hypothesis

  9. Variables Materials and apparatus Methodology Experimental Procedure

  10. Variables

  11. Materials and Apparatus

  12. Overview of Methods

  13. Methods – Preculture of yeast

  14. Methods – Preparation of solutions of Paracetamol and TCM

  15. Methods – Growth of yeast with Paracetamol and TCM

  16. Methods – Serial dilution and plating

  17. Data Analysis Statistical analysis • t-test was conducted to test if difference in mean number of colonies was significant • p < 0.05 – significant • p > 0.05 – insignificant

  18. Results Data Analysis Experimental Results

  19. Effect of high concentration of Paracetamol on growth of yeast

  20. Effect of high concentration of TCM on growth of yeast

  21. Effect of high concentration of TCM on growth of yeast • At a high amount (300 mg) of Paracetamol and TCM, there was inhibition of yeast growth. • Both are identified as stressor agents.

  22. 0 mg (Control) 0 mg (Control) Hormetic effect of Paracetamol on growth of yeast 3 mg Paracetamol Yeast growth was stimulated at 3, 15 and 30 mg Paracetamoladded. 15 mg Paracetamol 30 mg Paracetamol

  23. Hormetic effect of Paracetamol on growth of yeast

  24. Data Analysis • Hormetic effect of Paracetamol on growth of yeast

  25. 0 mg (Control) Hormetic effect of TCM on growth of yeast 3 mg TCM TCM (Angelica sinensis)stimulated growth of yeast at 3, 15 and 30 mg added. 15 mg TCM 30 mg TCM

  26. Hormetic effect of TCM on growth of yeast

  27. Data Analysis • Hormetic effect of TCM on growth of yeast

  28. 3 mg 0 mg (Control) 15 mg 30 mg 60 mg Hormetic effect of mixture of Paracetamol and TCM on growth of yeast The mixture of Paracetamol and TCM stimulated growth of yeast at all concentrations tested.

  29. Hormetic effect of mixture of Paracetamol and TCM on growth of yeast

  30. Data Analysis • Hormetic effect of mixture on growth of yeast

  31. Data Analysis

  32. Conclusion Limitations Further Study Applications Discussion

  33. Conclusions

  34. Limitations • Side effects to yeast cells cannot be observed solely based on growth of yeast cells • Only growth rate is studied; other effects are unknown • e.g. Expression of certain genes in response to stressor agents applied

  35. Further Study • Exposure of yeast to other stressor agents • e.g. UV radiation, antibiotics • Determine effect of stressor agents on level of protein synthesis in yeast

  36. Applications • Increasing the efficiency of large scale growth of yeast starter cultures in industries • Higher biomass of yeast results in higher yields of products formed, e.g. ethanol.

  37. References • Balzan, R., Sapienza, K., Galea, D.R., Vassallo, N., Frey, H. & Bannister, W.H. (2004). Aspirin commits yeast cells to apoptosis depending on carbon source. Microbiology, 150, 109-115. • Calabrese, E.J. (2004). Hormesis: a revolution in toxicology, risk assessment and medicine. EMBO Reports, 5, S37 – S40. • Calabrese, E.J. & Baldwin, L.A (2002). Defining hormesis. Human and Experimental Toxicology, 21, 91-97. • Hadley, C. (2003). What doesn’t kill you makes you stronger. EMBO Reports, 4, 924-926. • Tan, B.K.H. & Vanitha, J. (2004). Immunomodulatory and antimicrobial effects of some traditional Chinese medicinal herbs: a review. Current Medicinal Chemistry, 11, 1423-1430. • http://en.wikipedia.org/wiki/Hormesis

  38. Thank you

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