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# BIOMED Engineering Experimental proposal for Growth E.Coli

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### BIOMED Engineering Experimental proposal for Growth E.Coli

1. 1. Team 3 March 31, 2014
2. 2.  The purpose of this study is to create and validate a mathematical model of a growth curve of bacterial behavior after thermal shock at various temperatures
3. 3.  Escherichia coli (E. coli) is a type of bacteria commonly found in the intestinal tracts of large mammals  The growth and decay rate are also affected by:  Temperature  Initial concentration of bacteria  Presence of antibacterial substances  pH levels  Oxidation reduction potential
4. 4.  In our experiment, we demonstrate how the growth curve is affected by thermal shock  E. Coli grows well between 21oC to 50oC with an optimum at about 37oC .  E. coli can divide every 20 minutes  At temperatures of 0°C (32°F) E. coli are unable to divide, keeping the population stable  E. coli is killed above 70°C (160°F)
5. 5.  Lag phase: the population remains temporarily unchanged  Log phase: the cells divide at a constant rate depending on temperature conditions  Stationary phase: the population growth is limited by temperature  Death phase: the number of cells decreases The E.coli Growth Curve
6. 6.  The growth curves of colonies shocked at temperatures (45-650C) demonstrate longer lag times but accelerated exponential growth when compared to a control grown at 37°C
7. 7. WE WILL APPLY THIS EQUATION TO CREATE THE GROWTH CURVE MODEL[17] Where:  (Nmin) = minimum population of E.coli  (Nmax) = maximum population of E.coli  r = Temperature-dependent constant  C= Adjustment factor  N= number colonies at time t
8. 8. Materials and Equipment  Spectrophotometer and cuvettes  Inoculation Loop  1000μL and 100μL micropipettes  Beakers and hot plates  Incubator (37oC)  Reagents:  Distilled water and deionized water  Culture of E.Coli  Nutrient broth as a food source
9. 9. Thermal Shock:  Initially raise bacterial environment temperature to 450C, 550C, 600C, and 700C  Growth continued at 370C after thermal shock  Control group grown at 370C Measure growth  Create a concentration ladder  Measure cloudiness in a test tube as the number of cells increase (turbidity) using a spectrophotometer
10. 10.  Mintab and MATLAB software  Plot mathematical growth curve and experimental growth curves  Regression analysis
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