Appearance (Colour)
Light beige
Appearance (Form)
Free flowing, homogeneous powder
Solubility
42.00 gm/liter
Solubility before autoclaving (Clarity)
Very slightly to slightly opalescent, may have a slight precipitate
Gel strength
Firm, comparable with 1.5% agar gel
pH (25°C)
7.3 ± 0.2
Prepared Medium Appearance after autoclaving (Clarity)
Very slightly opalescent, may have a slight precipitate
Prepared Medium Appearance after autoclaving (Colour)
Light to medium amber
Cultural Response
Inoculate and incubate at 37°C for 24-48 hours with the following. Flood DNase Test Agar with 1N Hydrochloric acid prior to observing DNase activity
Organism
Staphylococcus aureus ATCC 25923
Inoculum (cfu) 10-100
Growth : Good
DNase Test : (+)ve
Organism
Staphylococcus epidermidis ATCC 12228
Inoculum (cfu) 10-100
Growth : Good
DNase Test : ( - )ve
Organism
Streptococcus pyogenes ATCC 19615
Inoculum (cfu) 10-100
Growth : Good
DNase Test :(+ )ve
Key
(+ )ve indicates positive reaction
( - )ve indicates negative reaction
Applications
Used for differentiation of microorganisms based on their production of deoxyribonuclease.
Composition
Ingredients
gms/lt.
Tryptose
20.00
Deoxyribonucleic acid
2.00
Sodium chloride
5.00
Agar
15.00
Directions
1. Add 42.00 gm powder to 1.0 liter of distilled/purified water and mix thoroughly.
2. Gently heat and bring to boiling.
3. Autoclave at 15 psi pressure at 121°C for 15 minutes.
