Determination of Microbial Mobility

Group 1Sheng Yun Huang

Klenna IstinoSharmane JarinRitz Hernandez

HUB41Mr. Joseph Bendo

De La Salle University-Dasmarinas

Wet Mount

Culture Method Hanging Drop

Wet Mount PreparationOrdinary Glass Slide

Observe under LPO

Place two loopfuls of inoculum at the center of the slide

Cover with coverslip

Paramecium

Microorganisms in Pond water-unicellular ciliate protozoa (ciliate group) -- Shape: shoe's sole.-ranges from about 50 to 350 µm in length- - simple cilia- Reproduce: binary fission- Habitat: water ; moist soil

Saccharomyces cerevisiae, the budding yeast, is the common yeast used

in baking ("baker's yeast") and brewing ("brewer's yeast").

Saccharomyces cerevisiae

• It is a independent movement brought about by different mechanisms of self-propulsion.

• It is the movement exhibited by particles suspended in liquids due to the bombardment of water molecules.

TRUE MOTILITY

BROWNIAN MOVEMENT

Hanging Drop Preparations

Place petroleum jelly on each corner of the cover slip

Place 2 loopfuls of innoculum at the center

Invert the depression slide

Advantage of hanging drop method: Like the wet mount, it preserves cell shape and arrangement. The sealed depression also slows down the drying-out process, so the organisms can be observed for longer periods. It also offers a better view of true motility.

Disadvantage of hanging drop method: It is far too risky to use with highly pathogenic organisms

Hanging Drop Preparations

Surface Tension

Example: Beading of rain water on the surface of a waxy surface, such as a leaf. Water adheres weakly to wax and strongly to itself, so water clusters into drops. Surface tension gives them their near-spherical shape, because a sphere has the smallest possible surface area to volume ratio.

Principle of Hanging Drop Preparations

Culture Method

Motility Agar is soft agar in a test tube (without a slanted surface). Cells are stab-inoculated into the agar (the top surface is not inoculated). Non-motile bacteria will only grow where they were inoculated. Motile bacteria will grow along the stab and will also swim out away from the stabbed area. Thus, a negative result is indicated by growth in a distinct zone directly along the stab. A positive result is indicated by diffuse (cloudy growth), especially at the top and bottom of the stab.

Procedures

1. Flame sterilize the inoculating needle until it glows red2. Gently touch the bacterial suspension Proteus Vulgaris with the cooled needle. Then, make a stab in the center of the motility medium.3. Flame sterilize the inoculating loop before placing it in the beaker with disinfectant.4. Incubate the medium at 37 C for 48 hrs.5. Observe for the dispersion of the bacteria from the line of streak outward6. Repeat steps 1-5 using Staphylococcus aureus and Micrococcus luteus.

Culture Method

Culture Method

Non-motile bacteria, such as this Staphylococcus aureus, do not move away from the stab line. Heavy growth appears only along the stab. The red color indicates where the bacteria are growing.

Another non-motile bacteria is Micrococus luteus

Culture Method

Motile bacteria (Proteus Vulgaris) swim away from the stab line. The growth around the stab line appears more diffuse or blurry.

Culture Method

• http://faculty.ccbcmd.edu/courses/bio141/labmanua/lab7/lab7.html

• http://www.austincc.edu/microbugz/handouts/Motility%20Handout.pdf

• http://www.fcps.edu/islandcreekes/ecology/paramecium.htm

References