Exercise 12: Bacteria motility Flashcards
What percentage of prokaryotic cells are motile by means of flagellum?
50%
What do you use as the primary stain when staining flagellum?
alcohol based crystal-violet soution
Where is the stain deposited when examining flagella?
around the flagella
What is true motility?
when the organisms show a purposeful, directional movement
What is brownian motion?
refers to the bombardment of water molecules on particles suspended in water
What types of false movement may be seen with brownian motion?
- organisms merely vibrating in place
- organisms moving cause by receding edges because of dehydration
What type of slide is prepared when wanting to see the organism motility?
Hanging drop
How do you prepare a hanging drop slide?
- use a toothpick to place four dots around the depression in the slide
- transfer a drop of water to cover glass, put culture in the water
- place the slide on top of the cover glass
- QUICKLY flip so the drop is suspended in the depression
With hanging drop slide and wet mount where should the iris diaphragm be?
all the way to the right to provide contrast
What is an indirect way to determine motility?
using a motility medium with TTC
What is TTC?
a semi-solid nutrient medium containing TTC (tetrazolium salt)
TTC is colorless in it’s oxidized form but what color does it change when reduced by microorganisms?
Red
What does TTC serve as?
a tracking dye
What does the TTC semisolid consistency do?
it ensures a motile organism will be able to swim away from the stab line
Why do bacteria “swarm” across a medium?
because they are communicating with each other to enhance their swarming behavior
