Artificial Sweetener Effects on Microbial Flora. Thomas Peilert Central Catholic High School

Transcription

1 Artificial Sweetener Effects on Microbial Flora Thomas Peilert Central Catholic High School

2 Problem Can the artificial sweetener Equal Original affect survivorship of Escherichia coli?

3 Microbial Flora Present in the respiratory, urinary, and digestive tracts as well as on skin Consists of mostly bacteria, few protists and fungi Most are harmless, but some can cause diseases Influences human anatomy, physiology, and overall health 10^14 bacteria are harbored within and on humans

4 Escherichia coli Cells are rod shaped and usually about 2 micrometers in length. Part of the human flora; found in the human colon and digestive tract. One of the most studied and widely understood types of bacteria. Reproduces rapidly Gram negative bacteria

5 Equal Original Sweetener Artificial Sweetener Zero Calorie Common in U. S.

6 Equal Original Sweetener (Ingredients) Dextrose Maltodextrin Aspartame Acesulfame Potassium

7 Purpose To investigate the effect of Equal Sweetener on E. coli survivorship

8 Null Hypothesis Equal supplementation will not significantly affect the survivorship of E. coli Alternative Hypothesis Equal supplementation will have a significant, positive affect on E. coli survivorship.

9 Materials LB media (0.5% yeast extract, 1% tryptone, 1% sodium chloride) DH5- alpha E. coli Spreader bar Turn table Ethanol Sterile test tubes Micropipettes and tips Incubator SDF (100mM KH2PO4, 100mM K2HPO4, 10mM MgSO4, 1mM NaCl Equal Original Sweetener) Bunsen burner Hot plate Stirrer Bar Vortex

10 Procedure for Experiment 1. E. coli was grown overnight in sterile LB Media. 2. Samples of the overnight cultures were added to fresh media in a sterile sidearm flask. 3. The cultures were placed in an incubator (37 C) until a density of 50 Klett spectrophotometer units was reached. This represents a cell density of approximately 10^8 cells/ml. 4. The cultures were diluted in sterile dilution fluid to a concentration of approximately 10^5 cells/ml. 5. A 10% Equal solution was sterile filtered. 6. The experimental variable was mixed with the appropriate amounts of SDF to create concentrations of 0%,.1%, 1%, and 10%.

11 Procedure for Experiment Solution ml of sterile water ml 10% Equal Solution 0% (control) % % % ml of E. coli µl of cell culture was then added to Equal Sweetener solutions, yielding a final volume of 10 ml and a cell density of approximately 10^3 cells/ml. 8. The solutions were vortexed and allowed to sit at room temperature for 15 minutes.

12 Procedure for Experiment (Continued) 9. After vortexing to evenly suspend the cells, 100 µl aliquots were removed from the tubes and spread on LB-agar plates. 10. The plates were incubated at 37 C for 24 hours. 11. The resulting colonies were counted visually. Each colony was assumed to have arisen from one cell.

13 Effect on Survivorship Average CFUs P-value Control.1% 1% 10% Concentrations of Equal

14 Dunnett's Test E. coli T Crit.= 2.31 Concentration of Equal T-value interpretation 0.1% Not Significant 1% Significant 10% Significant

15 Conclusions The alternative hypothesis was supported in all solutions except.1% as the 10% and 1% solutions significantly enhanced survivorship of E. coli

16 Limitations Limitations Plating was not perfectly synchronized Only four concentrations of Equal Only one type of exposure Only one exposure time Only survivorship was analyzed

17 Extensions Extensions Growth rate experiment Vary exposure times Vary type of exposure (Infusion) Wider range of concentrations Test different types of microbial flora

18 Works Cited Gallus, Scotti S. "Aspartame." Aspartame. American Cancer Society, n.d. Web. 24 Dec "Ingredients." Ingredients. Merisant Company, n.d. Web. 25 Dec Wilder, Jonah. "E. Coli." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 21 Dec Web. 25 Dec Mayo Clinic Staff. "Nutrition and Healthy Eating." Artificial Sweeteners and Other Sugar Substitutes. Mayo Clinic, 2 Feb Web. 24 Dec Pfeffer, M., S. Ziesenitz, and G. Siebert. "Acesulfame K, Cyclamate and Saccharin Inhibit the Anaerobic Fermentati." On of Glucose by Intestinal Bacteria. Springer International Publishing AG, 19 May Web. 25 Dec Shell, Ellen Rupple. "Artificial Sweeteners May Change Our Gut Bacteria in Dangerous Ways." Scientific American. Scientific American Magazine, 14 July Web. 25 Dec Holstein, Albert F. "Johns Hopkins: Diabetes Compares Non-caloric Sweeteners: Special Reports." Health After 50. Remedy Health Media, 2 Mar Web. 24 Dec

19 Data Control.1% 1% 10%

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