Amino acid-conferred resistance to melphalan. I. Structure-activity relationship in cultured murine L1210 leukemia cells.

Melphalan cytotoxicity to murine L1210 leukemia cells in culture was reduced in growth medium containing amino acids. Investigation of the effect of single amino acids revealed that the L-isomers of glutamine and leucine, but not the D-isomers, were the most active in decreasing cytotoxicity. Protection was concentration dependent, with maximum protection occurring at approximately 0.

Loss of deoxyribonucleic acid-thymine during thymine starvation of Escherichia coli.

A substantial loss of deoxyribonucleic acid-thymine occurs during thymine starvation of several thymine auxotrophs derived from Escherichia coli strains B, 15, and K-12.