Purpose
For distinguishing fluorescent pseudomonads from nonfluorescent pseudomonads
Ingredients
| Ingredient | 1 L | 500 ml |
|---|---|---|
| Distilled water | 1 L | 500 ml |
| proteose peptone #3 (Difco) | 20 g | 10 g |
| K2HPO4 | 1.5 g | 0.75 g |
| MgSO4•7H2O | 1.5 g | 0.75 g |
| glycerol | 10 mL | 5 ml |
| agar | 15 g | 7.5 g |
Instructions
- Mix water and peptone first
- Bring it to a boil and dissolve
- Add other chemicals
- Heat until all dissolve.
Notes
- This medium is the best general isolation medium for bacteria. Fluorescent pseudomonads produce a yellow pigment that fluoresces under longwave ultraviolet light (366 nm). Some isolates from the P. syringae group don’t fluoresce.
- This medium may not be suitable for longer term (more than 2 days) storage of Erwinia because some may die on it within a few days to a week.
- It is important to use proteose peptone #3 and not other peptones in order to allow colonies to produce fluorescent pigments.
- This mix is also commercially available as Difco Pseudomonas agar F.
References
- King, E.O., Ward, M.K. and Raney, D.E. (1954) Two simple media for the demonstration of pyocyanin and fluorescin. J. Lab. Clin. Med. 44, 301–307.
Schaad, N. W. 1980. Laboratory Guide for the Identification of Plant Pathogenic Bacteria. The American Phytopathological Society, St. Paul, MN. 72 pp. (p. 3)
Contributed by
From the Virginia Polytechnic Institute and State University Mediabook; Orignially created by Robert Wick; contributed by Mary Ann Hansen
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