By the name of Allah

Report about:

Bacterial Motility by:

Islam Radi 220050911

Supervised byDr. 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