| DNase Test Agar Base | |
| Description | A fine, free flowing, hygroscopic powder |
| Color | Light beige colored powder. |
| Solubility | Soluble in Distilled / de-ionized water at 50˚C |
| Color | Light yellow colored opalescent solution |
| pH | 7.30±0.2 at 25˚C (42.00 g/ l) |
| Solidification | 40˚C |
| Color | Light yellow colored opalescent gel or light blue with toluidine blue colored to slight opalescent g |
| Contents | |
| Ingredients | Gram/Litre |
| Tryptone | 15.00 |
| Soya Peptone | 5.00 |
| Deoxyribose nucleic acid | 2.00 |
| Sodium chloride | 5.00 |
| Agar | 15.00 |
| pH at 25˚C | 7.3 ±0.2 |
For detection of deoxyribonuclease activity of microorganisms & identification of pathogenic Staphylococci.
Dissolve 42.00 grams in 1000 ml distilled water. Boil to dissolve the medium completely. Sterilize by autoclaving at 121 ?C at 15 lbs for 15 minutes. Cool to room 40 to 45 ?C and distribute aseptically in petri plates with gentile shaking for equal distribution. Ensure complete solidification and inoculate test sample aseptically. The media can be fortified with 0.1g toluidine blue before sterilization for proper visualization. DNase activity results in the production of a bright pink reaction due to the metachromatic property of Toluidine blue. Some strains of Staphylococcus may be inhibited on DNase Test Agar by the Toluidine blue. Further confirmatory tests for identification should be carried out.