How do you make a DNase agar?

Preparation of DNAse agar:

  1. The medium is used at a concentration of 3.9 grams in every 100 ml of distilled water.
  2. Prepare and sterilize as instructed by the manufacturer.
  3. When the medium has cooled to 50-55°C, mix well and dispense in sterile petri dishes.
  4. Date the medium and give it a batch number.

What grows on DNase agar?

Overview. Deoxyribonuclease (DNase) test is used to determine an organism’s ability to hydrolyze DNA and use it as a source of carbon and energy for growth. Used mainly to differentiate Staphylococcus aureus from other Staphylococci.

How do you perform a DNase test?

Procedure of DNase (DNA hydrolysis test)

  1. Touch a colony of the organism under test with a loop and inoculate it onto a small area of the DNase test agar plate, in the middle of one of the marked sections to form a thick plaque of growth 5-10 mm in diameter after incubation.
  2. Incubate the plate at 37°C for 18-24hr.

What agar is used for DNase test?

BD DNase Test Agar is a standard medium for the determination of deoxyribonuclease. 5,6 It is used mainly in the identification of Staphylococcus aureus and its differentiation from S. epidermidis or other DNase negative staphylococci, and for the differentiation of Serratia from Klebsiella/Enterobacter.

What dye is used in the DNase test?

methyl green
Principle of DNase Test The media used to detect these enzymes can be made by using various indicators (toluidine blue or methyl green) or no indicators to detect the hydrolysis of DNA.

Why is HCl used in DNase test?

After incubation, DNase Test Agar requires addition of 1N HCl to the plate. HCl reacts with DNA (polymerized) in the medium, yielding free nucleic acid and a cloudy precipitate. In areas where DNA has been depolymerized, around and below DNase-producing colonies, a clear zone results.

Which test uses a medium that is both selective and differential?

MacConkey agar is an example of a medium that is both differential and selective. The presence of bile salts, as well as crystal violet, within the media prevent gram-positive organisms from growing.

What type of media is blood agar?

Blood Agar (BA) is an enriched medium used for the cultivation of bacteria or microorganisms that do not grow easily. These bacteria are called “fastidious” because they require a special, enriched nutritional environment compared to common bacteria.

Why does HCl need to be added to a DNase agar plate after incubation?

What are selective medium and differential medium?

Selective media are used to isolate a particular type of microorganism by giving a specific condition for the growth of that particular microorganism. Differential media are used to identify and differentiate microorganisms from a closely-related group with the help of unique growth patterns.

Can a medium be both selective and differential?

Is blood agar medium selective or differential?

differential media
Blood agar is differential media because 3 different types of hemolysis, or lysing of red blood cells, can be seen on this plate.