JoVE Encyclopedia of Experiments
Microbiology
0 views • 4:37 min • October 30th, 2025
Take a culture of Phormidium lacuna, a filamentous cyanobacterium.
Homogenize the culture to disperse the filaments, then centrifuge to pellet the bacteria.
Discard the supernatant and resuspend the pellet in nutrient-rich media.
Add plasmid DNA containing green fluorescent protein and antibiotic-resistance genes onto an antibiotic-supplemented agar plate.
Add the bacterial suspension over the DNA and incubate under light conditions.
The bacteria internalize the DNA using type IV pili. The introduced genes integrate into one of the multiple copies of the bacterial genome.
Redistribute the bacteria onto an antibiotic-supplemented agar plate to select the transformed bacteria.
Under a light microscope, identify healthy, green filaments indicating successful transformation.
Transfer the selected filaments to liquid media with a higher antibiotic concentration to enrich the transformed population.
Again, plate them onto agar with higher antibiotic levels for segregating transformants.
Visualize GFP expression under a fluorescence microscope to confirm successful transformation.
Begin by inoculating 50 milliliters liquid F2 medium into each of the two 250-milliliter flasks with one milliliter of P
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