Imperial College London/Notebook/11 September 2009

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==Testing==
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===Diauxic growth 11th Sep===
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====Protocol considerations====
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*Using spectrophotometer at 600nm
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*Blanks are all the relevant carbon sources, but subsequently realised that all blanks were roughly the same (within 0.03)
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**Therefore, subsequent readings= blank + 6 sample
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*Overnight culture had OD of 1.64. 
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**800ul was put into each sample of 40ml~ 0.033 OD
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**ie same initial OD
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*Grown in 6 separate 50ml falcon tubes and shaking in incubator at 28 degrees Celsius
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*1ml taken out at 1 hr intervals from the falcon tube and placed into spectrophotometer
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====Results====
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[[Image:Diauxic growth.jpg]]<br>
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[[Media:Diauxic growth_11-09.xls| Download raw data]]
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====Conclusions====
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*Glucose, as expected, had the highest growth rate
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*Cells under all secondary carbon source conditions appear to stop growth at 6 hrs. 
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** Therefore, we can suggest that the switch point is after 6 hours
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**However, further data at longer time points are required to confirm this.
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====Suggestions/Improvements====
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* Longer duration of taking readings (but currently limited to 8hrs- length of a day and multiplate reader evaporation)
 +
 +
* Earlier switch point can be induced by adding a smaller concentration of glucose to media
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**suggested 0.01% Glucose for next experiment (we predict it will take around 2 hours)
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 +
{{Imperial/09/TemplateBottom}}

Latest revision as of 16:44, 4 October 2009

Contents

Testing

Diauxic growth 11th Sep

Protocol considerations

  • Using spectrophotometer at 600nm
  • Blanks are all the relevant carbon sources, but subsequently realised that all blanks were roughly the same (within 0.03)
    • Therefore, subsequent readings= blank + 6 sample
  • Overnight culture had OD of 1.64.
    • 800ul was put into each sample of 40ml~ 0.033 OD
    • ie same initial OD
  • Grown in 6 separate 50ml falcon tubes and shaking in incubator at 28 degrees Celsius
  • 1ml taken out at 1 hr intervals from the falcon tube and placed into spectrophotometer

Results

Diauxic growth.jpg
Download raw data

Conclusions

  • Glucose, as expected, had the highest growth rate
  • Cells under all secondary carbon source conditions appear to stop growth at 6 hrs.
    • Therefore, we can suggest that the switch point is after 6 hours
    • However, further data at longer time points are required to confirm this.

Suggestions/Improvements

  • Longer duration of taking readings (but currently limited to 8hrs- length of a day and multiplate reader evaporation)
  • Earlier switch point can be induced by adding a smaller concentration of glucose to media
    • suggested 0.01% Glucose for next experiment (we predict it will take around 2 hours)

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