Question

How do both of the motility tests show motility? Explain how they work. (10 pts) TTT Arial 3 (12pt) T . E . 20

Answer 1

- Motility is the ability of an organism to move by itself by means of propeller like flagella unique to bacteria or by special fibrils that produce a gliding form of motility

- Motility by bacterium is mostly demonstrated in a semi solid agar medium. In semi-solid media, motile bacteria swarm and give a diffuse spreading growth that is easily recognized by the naked eye. The medium mainly used for this purpose is SIM ( Sulphide Indole Motility Medium) which is acombination differential medium that testes three different parameters, Sulfur Reduction, Indole Production and Motility.This media has a very soft consistency that allows motile bacteria to migrate readily through them causing cloudiness. The inoculum is stabbed into the center of a semisolid agar deep. Bacterial motility is evident by a diffuse zone of growth extending out from the line of inoculation. Some organisms grow throughout the entire medium, whereas others show small areas or nodules that grow out from the line of inoculation. The non motile bacteria will only grow in the soft agar tube and only the area where they are inoculated .

HANGING DROP METHOD : It shows that the organisms tends to assemble at the drop surface and with the help of a microscope we could examine whether the bacteria are motile or not

STABBING TECHNIQUE: It is a microscopic technique in which the growth occurrence showed up deviiating from the stab line indicated the motility of the organism and if growth only seem to appear at the stab line refers to the growth of a non motile organism