This document discusses bacterial motility and the different types and mechanisms of bacterial movement. It covers: - Motility is the ability of cells to move on their own using energy. The main types are flagellar movement and gliding movement. - Flagella are thin appendages that propel bacteria through rotation. Their structure includes a filament, basal body and hook. Arrangements can be monotrichous, lophotrichous or peritrichous. - Motility allows bacteria to find favorable environments and colonize host cells. Methods to detect motility include wet mount microscopy, staining techniques like Leifson's method, and using semi-solid media.

1. MOTILITY
DR.VAISHALI
POSTGRADUATE
DEPARTMENT OF MICROBIOLOGY

2. What is motility?
• Motility is the ability of a cell or organism to
move of its own accord by expending energy.
• Means of motility can range from animals' use
of muscles to single cells which may have
microscopic structures that propel the cell
along

3. Importance of Bacterial Motility
 Chemotactic behavior and survival.
Ability to change direction (moving away or towards
repellants or attractants), avoids unfavorable
conditions of habitat and choose favorable
environment
 Pathogenesis
• For attachment and colonization of cell wall of
host cell
 Microbiology
 Nutrition, Water Expulsion

4. Types of movement
There are 2 types of movement
 Flagellar movement:
Most motile bacteria
move by use of flagella, threadlike locomotor
appendages extending from the plasma membrane.
and cell wall.
 Gliding movement : movement without any appendages.
Brownian movement: movement exhibited by
particles suspended in liquids due to the
bombardment of water molecules.
example: Saccharomyces cerevisiae,
Staphylococcus aureus

5. FLAGELLA
• They are slender, thread like appendages
protruding from the cell wall.
• It measures up to 15 or 20 μm in length and
0.01-0.02 μm in thickness.

6. Arrangement of flagella
• Monotrichous-
V.cholera,pseudom
onas
• Lophotrichous-
spirillum
• Peritrichous-
S.Typhi, E.coli
• Amphitrichous-
Alcaligenes faecalis

7. ULTRASTRUCTURE OF FLAGELLA
• Filament : The longest and most obvious portion
is the filament, which extend from the cell
surface to the tip. It is made up of a protein called
flagellin.
• Basal body: A basal body is embedded in the cell.
The basal body attaches the flagellum to the cell
wall and plasma membrane. It is composed of a
series of rings connected to a central rod.
• Hook : A short, curved segmented, the hook is
present outside the cell wall and connects
filament to the basal body.

9. MECHANISM OF FLAGELLAR
MOVEMENT
• The filament is in the shape of a rigid helix,
and the bacterium moves when this helix
rotates.
• The basal body act as motor and cause
rotation.
• Flagellar rotation determines the nature of
bacterial movement

11. MOVEMENT BY OTHER THAN
FLAGELLAR ROTATION
• Spirochetes shows several types of movement such as
flexing, spinning, free swimming and creeping as they are
flexible and helical bacteria and lake flagella.
• Just within the cell envelop they have flagella like
structure which are know as periplasmic flagella or axial
fibrils.
• The axial fibrils are present in the space between inner
and outer membrane of cell envelope

12. GLIDING MOTILITY
• Some bacteria such as the species of cyanobacteri (eg.
Cytophaga) and mycoplasma show gliding movement when
they come in contact to a solid surface.
• However no organelles are associated with the
movement .
• In the members of cytophagales and cyanobacteria ,
movement helps to find out the substratum eg. Wood,
bark, etc for anchorage and reproduction.
• They secrete slime with the help of which they get
attached to substratum.

13. MOTILITY BY DIFFERENT BACTERIA

14. DETECTION OF MOTILITY
DIRECT DEMONSTRATION OF FLAGELLA:
• Tannic acid staining ( leifson’s method and
Ryu’s method)
• Electron microscopy
INDIRECT DEMONSTRATION OF MOTILITY:
• Craigie tube method
• Hanging drop method
• Semisolid medium
• Dark ground or phase contrast microscope

15. Procedure of Wet Mount Technique
• The organism needs to grow at room temperature in a blood agar
medium for 16 to 24 hours.
• Put a drop of saline onto the microscope slide.
• Now take a sterilized inoculating loop and remove little inoculum from
the culture plate by only touching the margin.
• Then, add the inoculum into the drop of water placed on a glass slide.
• After that, leave a glass slide undisturbed for about 15-20 minutes.
• Afterwards, place the coverslip to the faintly turbid drop of water and
immediately view it under the 40-50X of the objective lens.
• If the motile cells are visible, the process is followed by staining the
bacterial culture. Add a drop of Ryu flagella stain towards the one edge
of the coverslip, which ultimately penetrates the bacterial suspension
through capillary action.
• Then, observe the glass slide after 10 minutes, under the light
microscope upto the power of 100X.
• Finally, note down the results by examining the presence, number and
arrangement of the flagella.

16. Leifson’s Staining Method
• Firstly, take flagellated cell culture slant and put two to three
droplets of distilled water into the culture slant dropwise by using a
sterile pipette without disturbing the cell growth.
• Now incubate the slant for 20 minutes after adding water into it.
• Afterwards, take one drop from the above-prepared suspension
and put it on a clean slide. Then keep a slide in an inclined position.
• The drop needs to flow from one end to another end of the slide to
restrict the flagella folding on the cell.
• Now allow the smear to air dry.
• After the liquid completely evaporates, flood a glass slide with
Leifson’s stain until you observe a shiny thin film.
• Then wash the slide gently with water.
• Afterwards, treat a glass slide with 1 % methylene blue for one
minute.
• Observe the glass slide by putting a drop of oil immersion after
washing the slide with water and air-drying.

17. Result Interpretation
• Wet mount staining method: It stains the
flagella purple.
• Leifson’s staining method: It stains the flagella
red and the bacterial cells blue.

18. FLAGELLA UNDER EM

19. CRAIGIE’S TUBE METHOD

20. HANGING DROP METHOD

21. DARK FIELD MICROSCOPY

22. THANK YOU