YT and 2X YT are designed for cultivation of recombinant strains of Escherichia Coli . These media are also used for maintenance and propagation of M13 bacteriophage and several types of ssDNA bacteriophage.
YT is a moderately rich medium, where 2x YT is a nutritional rich medium providing nitrogen and growth factors allowing bacteriophage to reproduce in large quantities without exhausting the host cells. The presence of amino acids, nucleotides, vitamins and other nutritional elements, that the cell would otherwise have to synthesize, stimulates a luxurious growth and high yields of the host cells. Sodium Chloride is present in the medium to provide a suitable osmolarity.