Download Bacterial motility

By the name of Allah
Report about:
Bacterial Motility
by :
Islam Radi
220050911
Supervised by
Dr. Abdelraouf A. Elmanama
introduction
Most bacteria, but not all, that are motile, move by using
structures call FLAGELLA
Flagella are long rigid rod-like structures made of
repeating protein subunits
They are attached to a MOTOR located in the cell wall
that turns them like a propeller.
The flagella motor is powered by a flow of PROTONS,
sort
acting like electricity
As flagella rotate they turn or rotate like a propeller and drive the
bacterial cell through liquid
We will use this ability to detect whether the test bacteria are motile
or non-motile
•
•
The following flagellar
arrangements may be found
Monotrichous: a single flagellum at one
pole
amphitrichous : single flagella at both
poles
Lophotrichous: two or more flagella at one
or both poles of the cell
peritrichous : completely surrounded by
flagella
MOTILITY AGAR
**Motile bacteria require liquid to move.
Thus bacteria can propel themselves in broth or across the surface of a
wet agar plate.
**They will not however move when embedded in 1.5% agar, the
minimum concentration found in most agar media.
**Semisolid agar has a reduced agar concentration (0.4 %) that allows
flagellated bacteria to migrate from the site of inoculation..
**Semisolid media are prepared in tubes and are inoculated through
most of their length by stabbing with a needle.
**Thus after 48 hours of incubation, growth of a motile
organism will be observed as a turbid region extending
from the stab.
**Nonmotile bacteria will only grow along the stab line
**inoculate the tube by stabbing with the
needle to approximately three-quarters of
its depth
Be careful to bring the needle into the center of
the medium and not to touch the side of the tube
Incubate at room temperature for 48 hours
**Examine for growth
•
•
Motile
Non motile •
HANGING DROP SLIDE
**This method is commonly used to view
living organisms for the rapid
determination of motility.
**The hanging drop is prepared by
suspending a fluid sample from a coverslip
over a depression well in a specially
designed microscope slide.
MATERIALS
*Depression slides
**Cover slips
***Petroleum jelly
****Toothpicks
Procedure
*With the toothpick , put
a small amount of petroleum on
each corner of the cover slip
** place one or tow
loopful of a culture in the center of
cover slip
*** the depression slide is placed on the cover slip with the
depression over the frop of fluid
**** Examine with low power
THE END