Used in microbiology laboratories for the cultivation of microorganisms requiring vitamin B12 or folic acid for growth, particularly for isolating and culturing bacteria that cannot synthesize these vitamins themselves (auxotrophs). This medium contains thymidine, methionine, and purines, which support the growth of microorganisms with specific nutritional requirements. Commonly used in research laboratories in microbiology and microbial genetics to study nutritional requirements, mutations, or responses to various additives.