This study investigates the motility of Vibrio cholerae strains using motility agar. By analyzing the spread of red zones formed by metabolically active cells, researchers can determine the motility characteristics of different bacterial strains.
Begin with overnight cultures of Vibrio cholerae strains, pathogenic bacteria grown in a nutrient-rich medium.
Centrifuge the cultures to pellet the cells. Remove the supernatant containing extracellular compounds and resuspend the pellet in saline.
Next, dip a sterile wire inoculator into the culture and stab it vertically into the motility agar to deposit the bacteria below the surface without lateral spread.
Flame-sterilize the inoculator between each strain to prevent cross-contamination.
Incubate the plate to allow the bacteria to migrate through the motility agar.
The agar contains triphenyltetrazolium chloride, or TTC, a redox indicator that turns red upon reduction by metabolically active cells.
Motile strains reduce TTC across a broad area, forming a large red zone, while non-motile strains exhibit staining confined to the stab line.
The size and spread of the red zones indicate the motility of each strain.
Wash the cell pellet obtained from overnight culture. Inoculate motility agar plates by inserting an inoculating stab into the washed liquid culture and stab vertically into the media.
Ensure the inoculating stab does not bend while stabbing the agar. Between each inoculation, sterilize the wire stab using a Bunsen burner. Incubate the plates lid side up for 14-24 hours at 37 degrees Celsius.
After 14 hours, monitor the motility plates closely to prevent the overgrowth of cultures.
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