L-LYSINE DECARBOXYLASE BROTH

Media Used to Assist in the Identification of Members of the Enterobacteriaceae and other Organisms. Conforms with Australian Standard Methods.

Product Code: AM44 Categories: , ,

Description

Amyl L-Lysine Decarboxylase Broth AM 44 and Amyl Decarboxylase Broth Base AM 43 are based on the formulation of Taylor1 which is specified as an Australian Standard for use as a differential medium..2,8. When supplemented with the appropriate amino acid, the broth base is used as a means of differentiating microorganisms, particularly members of the Enterobacteriaceae, according to their ability to decarboxylate the amino acids l-lysine, l-arginine and l-ornithine.

After autoclaving and prior to inoculation of the organism under test, the medium will appear (at pH 6.8) as a bluish-purple colour. Following inoculation of the test organism into the decarboxylase medium, members of the Enterobacteriaceae will utilize the small amount of glucose in the medium fermentatively, producing an initial acid reaction in the medium. If the organism under test is unable to decarboxylate the amino acid present in the medium, then a yellow colour will develop, signifying a negative decarboxylase reaction. If however, the organism does possess the appropriate decarboxylase enzyme, e.g. lysine decarboxylase, then any l-lysine present in the medium is decarboxylated to form the alkaline substance cadaverine, and the medium will turn a deep purple colour. Similarly, decarboxylation of ornithine produces putrescine, whilst the degradation of arginine involves a dihydrolase enzyme splitting the molecule to form urea and ornithine, the alkaline urea turning the medium purple.Those organisms that are also ornithine decarboxylase positive will then proceed to produce further alkali as the ornithine is degraded.

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100gm, 2500gm, 5000gm, 500gm