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DNase agar is used primarily in clinical laboratories to differentiate pathogenic Staphylococcus aureus from other staphylococci based on deoxyribonuclease (DNase) activity. The tryptone provides the required carbon, nitrogen and vitamins. Sodium chloride maintains the osmotic balance. The addition of DNA to the base medium provides a simple method to check for DNase activity. Following incubation of the inoculated medium, the surface of the medium is flooded with a small quantity of 1M hydrochloric acid to precipitate the DNA. This results in the medium turning opaque. Organisms that can produce sufficient quantity of a DNase enzyme will hydrolyse the DNA resulting in a clear area around the colonies. Whereas DNase negative organisms will not produce clearing. NB: As with most tests of this type a positive result should not be taken in isolation and other appropriate tests, e.g. coagulase test, latex agglutination etc., should be carried out. -
LB agar (Lennox) is used for the cultivation and maintenance of recombinant strains of Escherichia coli and is based on the formulation stated by Lennox. This medium is typically used in molecular biology procedures such as the detection of phage or plasmid transformed bacteria. LB agar (Lennox) is prepared using 5 g/L of sodium chloride and this level varies from that described by Miller. This allows for additional sodium chloride to be added at the point of preparation if required. Enzymatic digest of casein provides the required nitrogen and carbon for organism growth. Vitamin B complex required by recombinant strains of E. coli are supplied by the yeast extract. Sodium chloride maintains the osmotic balance and provides sodium ions for membrane transport. Related Supplements : LS0035 Ampicillin Selective Supplement, LS0037 Kanamycin Selective Supplement
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Luria Bertani (LB) agar (Miller) is used for the cultivation and maintenance of recombinant strains of Escherichia coli and is based on the formulation stated by Miller. This medium is typically used in molecular biology procedures such as the detection of phage or plasmid transformed bacteria. LB agar (Miller) is prepared using 10 g/L of sodium chloride and this level varies from that described by Lennox. Enzymatic digest of casein provides the required nitrogen and carbon for organism growth. Vitamin B complex required by recombinant strains of E. coli are supplied by the yeast extract. Sodium chloride maintains the osmotic balance and provides sodium ions for membrane transport. Related Supplements : LS0035 Ampicillin Selective Supplement, LS0037 Kanamycin Selective Supplement
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Luria Bertani (LB) broth is used for the cultivation and maintenance of recombinant strains of Escherichia coli for molecular biology procedures. LB broth (Lennox) contains half of the amount of sodium chloride found in LB broth (Miller). Enzymatic digest of casein provides the required nitrogen and carbon. Vitamin B complex required by recombinant strains of Escherichia coli are supplied by yeast extract. Sodium chloride maintains the osmotic balance and provides sodium ions for membrane transport.
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Luria Bertani (LB) broth is used for the cultivation and maintenance of recombinant strains of Escherichia coli for molecular biology procedures.(1) Enzymatic digest of casein provides the required nitrogen and carbon. Vitamin B complex required by recombinant strains of Escherichia coli are supplied by yeast extract. Sodium chloride maintains the osmotic balance and provides sodium ions for membrane transport.
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Letheen agar modified is intended for use in the isolation of microorganisms from cosmetics. The casein peptone, meat peptone, beef extract and yeast extract act as carbon, nitrogen and vitamin sources in this medium. Glucose is a fermentable carbohydrate. Sodium chloride maintains the osmotic balance of the medium. The sodium bisulfite, lecithin and polysorbate 80 inactivates quaternary ammonium compounds. Polysorbate 80 neutralises phenols, formalin, hexachlorophene, and in combination with the lecithin, ethanol.
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Letheen broth when prepared with polysorbate 80 is used for the testing of quaternary ammonium compounds for antimicrobial activity. Letheen broth is recommended by the Official Methods of Analysis of the Association of Official Analytical Chemists (AOAC). (1) The enzymatic digest of animal tissue and beef extract act as carbon, nitrogen and vitamin sources in this medium. Sodium chloride maintains the osmotic balance of the medium. Lecithin inactivates quaternary ammonium compounds. Polysorbate 80 must be added to the medium prior to sterilisation. Polysorbate 80 neutralises phenols, formalin, hexachlorophene, and in combination with the lecithin, ethanol. REFERENCE (1) Association of Official Analytical Chemists. 1995. Official methods of analysis, 16th ed. Association of Official Analytical Chemists, Washington, D.C
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Letheen broth modified is intended for use in the isolation of microorganisms from cosmetics. The enzymatic digest of animal tissue, enzymatic digest of casein, yeast extract and beef extract act as carbon, nitrogen and vitamin sources in this medium. Sodium chloride maintains the osmotic balance of the medium. The sodium bisulfite and lecithin inactivates quaternary ammonium compounds. Polysorbate 80 must be added to the medium prior to sterilisation. Polysorbate 80 neutralises phenols, formalin, hexachlorophene, and in combination with the lecithin, ethanol.
