Bacterial Transformations!

In biology, we are currently performing a bacterial transformation. In order to understand bacterial transformation, it is important to understand the structure of Prokaryotes and their genetic material.

The genetic material of bacteria is located in the cytoplasm, because Prokaryotic cells do not contain a nucleus. The genetic material is concentrated in one region and is referred to as the nucleoid. However, the cell also contains important genetic information for the growth of bacteria on circular pieces of double-helix DNA called plasmids. These plasmids can replicate independently of the bacterial DNA. Bacteria can transfer these plasmids between one another, and the plasmids can be used to provide resistance to antibiotics, and in genetic engineering.

Plasmids can be used to make an organisms express a particular gene. Plasmids can be inserted into bacteria in a process called transformation.

In the lab we are doing, we will have four plates: -pGLO LB, -pGLO LB Amp, +pGLO LB Amp, and +pGLO LB Amp/Ara. LB is lysogeny broth, which is a nutrient-rich medium that is commonly used for bacterial growth. pGLO is the plasmid that will be inserted into the E. Coli bacteria. The -pGLO plates will not glow, and will be used as our controls. However, only the -pGLO LB will show normal growth. The -pGLO plate with  Ampicillin will not show any growth. Ampicillin is a type of bacteria that will inhibit the growth of E. Coli, so if the E. Coli does create colonies, it means that they are already resistant to Ampicillin without the pGLO plasmid. The +pGLO plate with Ampicillin but no Arabinose will not glow (because the Arabinose is one environmental factor that leads to the glowing E. Coli), but will have some colonial growth if the transformation was successful. If there is colonial growth, the transformation is successful because the E. Coli has resistance to the Ampicillin bacteria. The +pGLO with both Ampicillin and Arabinose will glow in UV light, because the Arabinose turns the gene for GFP (Green Florescent Protein) on, and the bacteria transcribes the DNA to make the protein GFP. This protein glows in UV light because the electrons in the protein are excited by the light and jump up to the next highest level in the electron cloud, emitting energy in the form of light.

We have set up the plates, and we will let them grow until next block (about two days). On Friday, we will look at them under UV light.