Differentiate aerobic actinomycetes by hydrolysis of casein, xanthine, tyrosine, and starch with Thermo Scientific™ Remel™ Nocardia Quad. A taxonomic scheme to differentiate these genera based on biochemical characteristics was developed by Mishra et al1. McGinnis et al. simplified it to identify the most commonly isolated actinomycetes by including tests for casein, xanthine, and tyrosine degradation2. Starch is added to Nutrient Agar to presumptively differentiate Streptomyces from Nocardia based on the inability of Nocardia species to hydrolyze starch3.
|Request A Quote
The aerobic actinomycetes as a group are gram-positive, catalase-positive bacteria that may be presumptively identified by staining properties, microscopic morphology, and substrate degradation. Certain actinomycetes produce a hydrolytic enzyme that degrades the skim milk in Casein Agar, which is demonstrated by clearing of the agar surrounding the area of growth.
Casein agar contains skim milk that acts as a substrate for the hydrolytic enzyme produced by some actinomycetes.
Xanthine and Tyrosine Agars contain beef extract that provides carbohydrates, vitamins, nitrogen compounds, and salts. The peptones present in these media provide nutrients in the form of amino acids and peptides.
Starch Agar contains potato starch which acts as a substrate to detect amylase production. This is demonstrated by clearing of the agar surrounding the area of growth, and easily detected upon addition of Gram Iodine or Lugol’s iodine.
Not all products are available for sale in all territories. Please inquire.
Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.