How to Use Bacteria in Genetic Engineering

Bacteria are useful tools in genetic modification. Through the use of plasmids, circular portions of interchangeable bacterial DNA, organisms, such as other bacteria, can be transformed genetically. This guide describes the basic methods involved in using bacteria for genetic engineering of another organism.

Things You'll Need

• Non-lethal bacteria species (preferably a harmless variant of Escherichia coli)
• Second non-lethal bacteria species
• Petri dish
• Bacteria incubator
• Restriction enzymes for target gene
• 2 Sterile loops
• Hot water bath
• Test tube

Instructions

Preparing the Gene of Interest

1. Obtain a sample of the first bacteria species by swabbing the enclosed colony with a sterile loop.

2. Wave the inoculated loop in a test tube through a water bath at approximately 48 degrees Celsius for five seconds.

3. Add a few milliliters of restriction enzyme to the test tube and heated, inoculated loop. This restriction enzyme varies depending on the gene of interest that will be transferred to the other bacterial species.

Transforming the Other Bacteria Species

1. Dip a second sterile loop into a colony of the second bacteria species, the one that is to be transformed.

2. Spread the bacteria evenly across a Petri dish containing agarose medium by sliding the inoculated loop across the agarose.

3. Let the bacteria incubate for two days in an incubator, such that bacterial colonies are formed.

4. Add the mixture created earlier containing the gene of interest to the Petri dish containing the bacterial colonies.

5. Let the bacteria incubate for two days in the incubator. This allows the species to uptake the genes added to the dish and insert them into their genomes.

6. Devise a method to test the transformed bacteria to see if they assimilated the genes. For example, if the gene added grants the bacteria antibiotic resistance, it may be practical to add disks of ampicillin to the agar plate. If they survive, they took up the gene.

Tips & Warnings

• When choosing a gene to use for transformation, choose a gene that can be taken from another bacterium easily.

• Also be sure to pick a gene that can be tested to see if the procedure worked. For example, a gene that makes bacteria glow is easily testable by sight.

• Use extreme care when working with bacteria, lethal or non-lethal.

• Wash hands with antibacterial soap before, after and during any work with bacteria in genetic engineering.

Resources

• Read this Article in Spanish
• Sample bacterial transformation lab