JoVE Encyclopedia of Experiments
Microbiology
0 views • 3:19 min • September 26th, 2025
Begin by inoculating a pathogenic bacterium into a tube containing a liquid medium.
Incubate to promote bacterial proliferation, then transfer the culture into fresh tubes.
Spin down the cells into pellets and discard the supernatant.
Resuspend the bacterial pellets in buffer solutions containing increasing concentrations of flavin mononucleotide (FMN), a photosensitizer, and a buffer solution without FMN to serve as a control.
Mix the tube contents thoroughly and transfer the suspensions into glass tubes.
Expose the tubes to visible light to photoactivate FMN, which reacts with molecular oxygen to generate reactive oxygen species (ROS).
The ROS damages bacterial cellular components, thereby reducing bacterial viability.
Transfer the sample aliquots onto solid media, spread them evenly, and incubate to allow surviving viable bacteria to grow into colonies.
Post-incubation, quantify the colonies and calculate the percentage reduction in bacterial viability compared to the control to assess the dose-dependent effect of FMN.
Inoculate a colony of Staphylococcus aureus into 10 milliliters of lysogeny broth in a 15-milliliter screw-capped test tube. Grow the culture at 37 degrees Celsius for 16
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