What is R2A Agar made of?
Peptone supplies essential amino acids and nitrogenous substances necessary for growth. Dextrose is added as a carbon source of energy. Yeast extract supplies B-complex vitamins and serves as a growth enhancer. Soluble starch is added as a neutralizer and sodium pyruvate stimulates the growth of stressed bacteria.
What is the purpose for the R2A media?
INTENDED USE: This media is used for detection of heterotrophic bacteria in water, especially treated water. R2A Medium can be used as a pour plate, spread plate or membrane filter media1 as a subculture medium.
What is Reasoner’s 2A Agar?
R2A agar (Reasoner’s 2A agar) is a culture medium developed to study bacteria which normally inhabit potable water. These bacteria tend to be slow-growing species and would quickly be suppressed by faster-growing species on a richer culture medium.
What bacteria can grow on Cetrimide Agar?
Cetrimide Agar is a solid selective medium used for the isolation and identification of Pseudomonas aeruginosa from different material, modified acc. to Brown and Lowbury (1965). Cetrimide inhibits bacterial growth except Pseudomonas aeruginosa and enhances fluorescein and pyocyanin pigment production.
What grows best in R2A Agar?
R2A agar supports the growth of Escherichia coli, Enterococcus spp, Pseudomonas spp, Streptococcus spp, Staphylococcus spp, and others. It does not support the growth of most molds.
What is peptone in microbiology?
Peptone water is a non-selective broth medium that can be used as a primary enrichment medium for bacterial growth. It is a microbial growth medium composed of animal tissue peptate digestate and sodium chloride.
What is the difference between complete medium and minimal medium?
Complete medium contains all the substances required by bacteria for growth and reproduction. Minimal medium contains only nutrients necessary for prototrophic (wild-type) bacteria.
How do you make r2a agar?
- Suspend 18.2 g of the medium in one liter of purified water.
- Heat with frequent agitation and boil for one minute to completely dissolve the medium.
- Autoclave at 121°C for 15 minutes.
- Cool to 45-50°C.
How do you use Cetrimide Agar?
Preparation of Cetrimide Agar
- Add 45.3 gm of the medium in 1 litre of distilled water.
- Add 10ml of glycerol and boil to dissolve completely.
- Sterilize by autoclaving at 121°C for 15 minutes.
- Cool the medium to approximately 50°C and pour into sterile Petri dishes.
What is the pH of TSA and PDA?
In addition, Potato Dextrose Agar with TA contains: Tartaric Acid. 1.4 gm. Tartaric Acid 1.4 gm. Final pH of 3.5 +/- 0.3 at 25 degrees C.
What are the examples of heterotrophic bacteria?
Some examples of heterotrophic bacteria are Agrobacterium, Xanthomonas, Pseudomonas, Salmonella, Escherichia, Rhizobium, etc.
How do you make peptone broth?
Preparation of Peptone Water
- Suspend 15.0 grams in 1000 ml distilled water.
- Add the test carbohydrate in desired quantity and dissolve completely.
- Dispense in tubes with or without inverted Durhams tubes and sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes.
How are peptones made?
Peptone, a protein decomposition product, is made by incomplete hydrolysis process of the protein originated from beef, casein, milk powder, gelatin, soy protein, silk protein, fibrin, etc. The commercially available products are mainly light yellow to brown yellow powder.
What is an example of minimal media?
Minimal media is a defined medium with the composition varying on the microorganism being cultured. Typically, this medium contains a carbon source such as a sugar/succinate, various inorganic salts (salts of essential elements like magnesium, nitrogen, phosphorous and sulphur) and water.
Why is glycerol added to Cetrimide Agar?
Cetyltrimethylammonium bromide (Cetrimide) is the selective agent and inhibits most bacteria by acting as a detergent. When in contact with bacteria, causes the release of nitrogen and phosphorous from the bacterial cell other than Pseudomonas aeruginosa. Glycerol is supplemented as a source of carbon.
What is Agar made of?
Agar is a galactose-based heterogenous polysaccharide derived from red algae. It is a heterogenous polysaccharide composed of agarose and agaropectin polymers. A typical agar composition is 70% agarose and 30% agaropectin.
What bacteria can grow on cetrimide?
Although cetrimide agar is strongly selective for Ps. aeruginosa, some strains of Gram-negative bacilli (especially Klebsiella spp. and Providencia) can grow on it. To suppress the growth of these organisms, Tinne et al.