DNase test agar base w/o DNA is recommended with the addition of DNA it is used for detection of deoxyribonuclease activity of bacteria and fungi, especially Staphylococci. Tryptone and soya peptone provides essential nutrients. DNase activity is detected by flooding the surface of the medium with 1 N HCl and observing for clear zones around the colonies on the medium (with added DNA and mannitol and no bromothymol blue). In the absence of DNase activity, cloudy precipitate is formed due to reaction of HCl with nucleic acids. When bromothymol blue is used, yellow zones are formed. Further confirmatory tests for the identification should be carried out. Serratia marcescens positive reaction, change in color from green to yellow around the growth.
Application: For Laboratory Chemicals, Analytical Purpose, Biochemical Analysis
- Appearance: Cream to yellow homogeneous free flowing powder
- Gelling: Firm, comparable with 1.5% Agar gel
- Color and Clarity of prepared medium After addition of Bromothymol blue : Blue colored, clear to slightly opalescent gel forms in Petri plates
- Reaction: Reaction of 5.2% w/v aqueous solution at 25 deg C. pH : 7.3±0.2