%0 Journal Article %A GILBOE, D. P. %A SMITH, W. G. %A HENDERSON, L. M. %T Characteristics of Two Lysine-independent Strains of Streptococcus faecalis %D 1969 %J Microbiology, %V 57 %N 2 %P 239-245 %@ 1465-2080 %R https://doi.org/10.1099/00221287-57-2-239 %I Microbiology Society, %X SUMMARY The ease of isolation of two mutants of Streptococcus faecalis 8043 appeared to be the result of the presence in the parent strain of a system for slow synthesis of lysine. The mutation to lysine independence occurred when the population became large enough for a significant number of spontaneous mutational events to occur. The slow growth and lysine depletion lysis of the parent strain selected for the new strain. The hydroxylysine-resistant mutant can arise from the parent strain or from the lysine-independent strain and is selected for by growth in a medium containing hydroxylysine. The three strains appeared to be identical by all tests employed except in their responses to lysine and hydroxylysine. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-57-2-239