pGLO Lab

        In the pGLO lab, we added plasmids to E. coli bacteria containing araC, GFP, and ampicillin resistance genes. After heat shocking the bacteria, we plated them onto luria broth with ampicillin nd arabinose and waited for the colonies to grow.
        Though my group's bacteria failed to receive the plasmid successfully due to possible errors in adding the plasmid and heat shocking, we recorded data from a more successful group to analyze.

Our failed plates (note no GFP in bacteria seen under black light)

Another group's successful plates
(from left to right: -pGLO with LB,
+pGLO with LB and amp,
+pGLO with LB, amp, and arabinose)

Plate	Number of Colonies	Color of colonies under room light	Color of colonies under UV light
- pGLO LB	1 large colony with incoherent boundaries	Murky gray	Yellowish gray
+ pGLO LB/amp	9 large colonies	Murky gray	Yellowish gray
+ pGLO LB/amp/ara	7 colonies	Murky gray	Bright green

        There were likely about 10,000,000 bacteria in each 100 uL E. coli sample plated, assuming about 100,000,000 in each milliliter. This estimate takes into account the millions of bacteria that exist everywhere and gives a reasonable number without a reference, though an equally large number is possible as well.

        Out of these, a very small number of bacteria (i.e. around 1,000,000) successfully received the plasmid. These transformed bacteria had the pGLO gene as well as ampicillin resistance, allowing them to be isolated in the luria broth, as the ampicillin killed off the rest of the bacteria. In addition, arabinose acted like a trigger to activate the GFP intron in the pGLO plasmid, allowing the bacteria to produce GFP when the sugar was present. Where arabinose was absent, (as in the +pGLO LB/amp plate) the gene was not expressed; in the plate with the trigger sugar, the gene was expressed, and the bacteria glowed.

        This kind of genetic engineering is very useful and can be applied in a variety of places. GFP is used in many areas, including as a cell marker, in which it is added to plasmids of interest to gauge how many bacteria have successfully taken in the plasmid; as a transcription reporter, in order to monitor the expression under a certain promoter; and in FACS (fluorescence-activated cell sorting), to separate different cells based on their fluorescent signals. Furthermore, genetic engineering involving the enzyme Cas9 in CRISPR editing can be done in order to modify the genome of different organisms, including humans, with low costs and equipment. This can been done to change the inheritance of traits or characteristics of embryos, and is currently being studied.