Amino acid requirements of Legionella pneumophila.

The amino acids required for growth and as energy sources by 10 strains of Legionella pneumophila were determined by using a chemically defined medium. All strains required arginine, cysteine, isoleucine, leucine, threonine, valine, methionine, and phenylalanine or tyrosine. Most strains (7 of 10) required serine, and two strains had to be supplied proline before growth could be established. All 10 strains used serine and, to a lesser extent, threonine as the sole sources of carbon and energy. The Y serine calculated was 94.9 +/- 8.5 g (dry weight) of cells/mol of serine. Assuming that the value of Y adenosine 5'-triphosphate is 10.5, these results indicate that oxidative catabolism of 1 mol of serine yielded approximately 9 mol of adenosine 5'-triphosphate. This high yield suggests that although serine was the major source of carbon, other amino acids may also be metabolized.