SD Growth Medium w/o HIS-LEU-TRP

Principle and Interpretation :

SD Growth Medium w/o HIS-LEU-TRP is a synthetic defined media for the selective growth of Saccharomyces cerevisiae. Synthetically Defined media known as Yeast Nitrogen Base Media for the growth of yeast cells were first cited by Wickerham (1, 2). Synthetic defined Growth Medium w/o HIS-LEU-TRP includes a yeast nitrogen base along with ammonium sulfate and dextrose as the carbon source, which is further supplemented with various amino acids except histidine, leucine and tryptophan. This makes it a triple dropout growth medium for yeast cells. A histidine, leucine and tryptophan auxotrophic yeast mutant strain cannot grow on this media but a wild-type or a histidine, leucine and tryptophan prototrophic yeast strain can grow. The histidine, leucine and tryptophan auxotroph has mutation in the genes (e.g. HIS3, LEU2 and TRPI) of the histidine, leucine as well as tryptophan synthesis pathway and this mutant strain will grow in this medium if histidine, leucine and tryptophan are supplied from outside e.g. from plasmids which contain HIS3, LEU2 and TRP1 gene (3). For this purpose, a his3leu2trp1 mutant strain of S. cerevisiae is transformed with HIS3, LEU2 and TRPI containing plasmid and the transformants can be selected by growing the cells on SD Growth Medium w/o HIS-LEU-TRP.