Team:Austin Texas/human practices

From 2014.igem.org

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(Measuring Caffeine Content)
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==Measuring Caffeine Content==
==Measuring Caffeine Content==
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[[file:UT_Austin_E._coli_coffee_cultures.jpg|300px|thumb|left| Cultures of knockout strain grown with collected coffee samples.]]
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[[file:UT_Austin_E._coli_coffee_cultures.jpg|250px|thumb|left| Cultures of knockout strain grown with collected coffee samples.]]
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[[file:UT_Austin_caffeine_growth_standard_curve.png‎|200px|thumb|right| Standard growth curve of knockout strain grown with different amounts of caffeine.]]
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The ''E. coli'' we used are an engineered strain, previously made by the [https://2012.igem.org/Team:Austin_Texas 2012 UT Austin iGEM team].  This strain has had its normal guanine synthesis pathway knocked out, but contains a plasmid with a set of genes that enables the organism to synthesize guanine from xanthine and many of its derivatives, including caffeine. Without caffeine (or other xanthines), the strain cannot grow.  When caffeine is added, the strain can demethylate the caffeine moleculesm yielding xanthine, and from there the ''E. coli'' can synthesize guanine. It then grows normally until the caffeine is completely metabolized, at which point the cells can no longer synthesize guanine, and cease to grow. Thus, by looking at the relative growth of the strain with different samples of coffee and comparing it to a standard curve of growth in solutions with known amounts of caffeine, we could reliably measure the amount of caffeine in the coffee.
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The ''E. coli'' we used are a synthetic strain, previously made by the [https://2012.igem.org/Team:Austin_Texas 2012 UT Austin iGEM team].  This strain has had its normal guanine synthesis pathway knocked out, but contains a plasmid with a set of genes that enables the organism to synthesize guanine from xanthine and many of its derivatives, including caffeine. Without caffeine (or other xanthines), the strain cannot grow.  When caffeine is added, the strain can demethylate the caffeine molecules to make guanine. It then grows normally until the caffeine is completely metabolized, at which point the cells can no longer synthesize guanine, and cease to grow.[[file:UT_Austin_caffeine_growth_standard_curve.png‎|200px|thumb|center| Standard growth curve of knockout strain grown with different amounts of caffeine.]] Thus, by looking at the relative growth of the strain with different samples of coffee and comparing it to a standard curve of growth in solutions with known amounts of caffeine, we could somewhat accurately measure the amount of caffeine in the coffee.
 
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The protocol was simple: We provided our Caffeinated coli with a diluted sample of coffee we had acquired from the various shops, and then compared the relative growth rates by taking an OD600 value at a time point. The simplicity of the project was the key its success. It provided a glimpse into the exciting new world of synthetic biology for the new members, and allowed them to learn vital skills that were used in day to day research during the summer.  
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The protocol was simple: We provided our Caffeinated coli with a diluted sample of coffee we had acquired from the various shops, and then compared the relative growth of each culture by measuring the absorbance at 600 nm (OD600 for short). The simplicity of the project was the key its success. It provided a glimpse into the exciting new world of synthetic biology for the new members and allowed them to learn vital skills that were used in day to day research during the summer.  
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The results we found can be seen in Figure 1. below.  
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Our results can be seen in Figure 1, below.  
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[[file:UT_Austin_relative_caffeine_levels_coffee_shops.png‎|600px|center| Figure 1. Relative levels of caffeine in house coffee samples from around Austin.]]
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[[file:UT_Austin_relative_caffeine_levels_coffee_shops.png‎|800px|center| Figure 1. Relative levels of caffeine in house coffee samples from around Austin.]]
== SXSW Create ==
== SXSW Create ==

Revision as of 13:13, 16 October 2014