Hanging drop method of motility
Hanging drop method use to observe morphology and motility of microorganisms under microscope.
Motile bacteria such as;
Escherichia coli
Salmonella
Vibrio
Pseudomonas
Articles requirement;
1. Glass slide with cavity
2. Cover slip
3. Fresh bacterial culture 18- 24 hours old.
(Broth culture of bacteria)
4. Paraffin wax
5. Inoculation loop
6. Microscope
7. Burner
To sterilized the inoculation loop
Prodcedure of Hanging Drop Method of Motility
1. Take a cover slip.
2. Place a drop of bacterial sample on cover slip.
Inoculation loop is used to transfer bacteria sample to cover slip.
2. Apply the petroleum jelly over four corner of coverslip, so that easily stick cavity slip to glass slide.
3. Place the glass slide in such a way the cavity covers a drop.
The drop hangs from the coverslip, and the petroleum jelly forms a seal that prevents evaporation.
4. Slide in then quickly inverted. Glass slide with circular concavity in centre into which a drop of fluid, containing microorganism's hangs from coverslip.
5. Now observe under microscope
Observation and Result
If bacteria are motile, seen to have darting (move suddenly). Motility through the medium in which they are suspended.
Bacteria which doesn't have ability of movement in surrounding medium. In which it remain suspended. It is non-motile bacteria.
For example;
Bacteria campylobacter and vibrio cholerae display very active motility (darting motility) which appears as tiny dots darting.
This method used to identify motility, shape of bacteria (oval, rid, comma), arrangement of bacteria (pair, single, four, chains, cluster), and size of bacteria.
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