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From 2010.igem.org

GFP Soil Visibility Experiment

We transformed e. coli (strain ????) with a constitutive pTet promoter (BB????) behind GFP (BB????). A suspension (concentration ????) of this strain was mixed with soil samples to determine to fluorescence characteristics of e. coli on soil and to see how long they lived for in sterile and non-steile soil.

Following are some preliminary results:

Fresh soil coli mix	Unsterilised soil with 3x200ul drops of e. coli suspension added 10 minutes before imaging. The e. coli is well mixed and the glow is relatively diffuse.
Coli in sterile soil for 24hrs	Sterilised soil mixed with the e. coli and left to grow for 24 hours before imaging. Many colonies survived, though their spread of the soil particles was heterogeneous.
Coli in unsterile soil for 24hrs	Unsterilised soil mixed with the e. coli and left to grow for 24 hours before imaging. Enough of the coli survived to produce a measurable signal - though there appears to be less luminescence than in the sterile soil samples.
Coli in sterile soil for 24hrs	Sterilised soil mixed with the e. coli and left to grow for 24 hours before imaging. The two large yellow fluorescent objects were identified to be small fragments of rock. It may be important to make sure that elements like this that produce a large fluorescent signal do not affect our measurements.