Transcript Wasson The Effect of Honey on E. Coli

The Antibacterial Properties of
Honey
Megan Wasson
Oakland Catholic High School
Problem
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Can honey significantly inhibit the survival
of bacteria colonies?
Motivation and Background
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Observations of healing properties of honey have been
noted by many ancient scientists and scholars including
Hippocrates.
Using a natural substance such as honey for antimicrobial
purposes offers a holistic solution for modern medicine.
Majority of raw honeys have the enzyme glucose oxidase
which produces hydrogen peroxide that has definite
antibacterial properties.
Manuka Honey is noted in the scientific literature for its
antibacterial properties but does not have the enzyme
glucose oxidase.
Purpose
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To observe the effects of various honey
solutions on E. coli colonies-selected
bacteria medium.
Specifically, to investigate if the honey
solutions will hinder the survival rate of the
E. coli colonies.
Hypothesis
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The various honey solutions will inhibit the
survival rate of E. coli colonies.
Null Hypothesis
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The various honey solutions will not
significantly impact the survival rate of E.
coli colonies.
Materials
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LB (luria broth)
LB agar plates
DH5- alpha E. coli
Spreader bar
Turn table
Ethanol
Sterile test tubes
Micropipettes and tips
Incubator
Sterile water
Organic Honeydew Honey
Bunsen burner
Hot plate
Stirrer Bar
Vortex
Microsoft Excel
Experimental Thrusts
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Principal Experiment: Collect data to
confirm or negate hypothesis of honey
impacting E. coli colony survival rate.
Additional Experiment: Conduct test to
prove that the honey was absorbed into the
agar plate and to further confirm or negate
the hypothesis.
Procedure for Principal
Experiment
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250 mL of honey was heated to reduce the high viscosity.
Designated amount of water, honey, and E. coli was
micropipetted into a tube which was vortexed.
Solution
mL of sterile
water
mL of honey
mL of E. coli
0% (control)
9.9
0.0
0.1
10%
8.9
1.0
0.1
25%
7.4
2.5
0.1
50%
4.9
5.0
0.1
Procedure for Principal
Experiment (Continued)
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0.1 mL of each solution was micropipetted
onto a designated agar plate
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Total of eight plates for each solution
Solution was spread on plate with spreader
bar and turn table
Plates were incubated at 37ºC overnight
Principal Experiment Results: Average
Number of E. coli Colonies vs. Honey Solution
P-value= 7.69x10^-3
Average Number of E. coli Colonies vs. Honey Solution
Amount of E. coli Colonies
450
400
350
300
352
318
293
281
Control
250
10%
200
25%
150
50%
100
50
0
Honey Solution
Principal Experiment Results:
Dunnett Test Results
T-Critical=2.88
Honey Solution
T- Value
Interpretation
10%
1.686
Insignificant
25%
2.925
Significant
50%
3.471
Significant
Procedure for Additional Experiment:
Direct Exposure to Heat and Cold
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Conducted to ensure honey was inside agar.
Specific steps included the following:
1. 1 mL of pure honey was pipetted on agar plate.
2. 12 plates were placed in incubator at 37ºC for 30
minutes and 12 plates were placed outside in 0ºC for
30 minutes.
3. 0.1 mL of 0%, 10%, or 50% solution was placed and
spread on designated dish.
–
Total of 4 dishes for each solution for each temperature
4. Dishes were placed in an incubator at 37ºC overnight.
Additional Experiment Results: Direct
Exposure to Heat: Average Amount of E. coli
Colonies vs. Honey Solution
P-Value= 1.74x10^-2
Direct Exposure to Heat: Average Amount of E.
coli Colonies vs. Honey Solution
Amount of E. coli Colonies
450
400
350
389
325
283
300
Control
250
10%
200
50%
150
100
50
0
Honey Solution
Additional Experiment Results: Direct
Exposure to Cold: Average Amount of E. coli
Colonies vs. Honey Solution
P-Value=2.13x10^-2
Amount of E. coli Colonies
Direct Exposure to Cold: Average Amount of E. coli
Colonies vs. Honey Solution
450
400
350
300
250
200
150
100
50
0
411
377
330
Control
10%
50%
Honey Solution
Conclusions
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Hypothesis was supported and null
hypothesis was rejected as the various
honey solutions significantly inhibited the
survival rate of E. coli colonies.
Limitations
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Honey was extremely viscous and pipettes
were not designed to distribute precise and
accurate amounts of liquid.
Some plates did not receive immediate
transport to the incubator which provides
the necessary environment to for the
growth of E. coli.
Future Experimentation
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Test the survival rate of other bacteria with
honey solutions.
Compare the effects of honeys with glucose
oxidase enzyme and the effects of Manuka
honey on bacteria.
Create mixtures of honey and vitamins and
apply the mixtures to bacteria and observe
its survival rate.
Sources and Acknowledgements
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Active Manuka Honey Association. AMHA. 2002. Web. 3 Oct 2010.
Cimolai, Nevio. Sweet Success? Honey as a Topical Wound Dressing. BC Medical Journal.
2 March 2007. Web. 28 Sept 2010.
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Knox, Angie. Harnessing Honey's Healing Power. BBC. 4 June 2004. Web. 30 Sept 2010.
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Sivasubramaniam, Lakshmi. Medicianl Properties of Liquid Gold: Honey. Pharmainfo.net.
16 Dec 2005. Web. 28 Sept 2010.
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Slater, Michael. Does honey have healing benefits? MSN. 27 Nov 2006. Web. 30 Sept
2010.
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A special thank you to Mr. Krotec and Central Catholic High School for help and use of
facilities