ROLE OF α,ε-DIAMINOPIMELIC ACID IN THE CELLULAR INTEGRITY OF ESCHERICHIA COLI

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Abstract
A study of the role of [alpha], [epsilon]-diaminopimelic acid (DAP) in the nutrition of the DAP requiring auxotroph E. coli strain 173-25 indicates that the cells will lyse at a rapid rate when the exogenous DAP becomes limiting. Addition of DAP at various time periods during the growth cycle of E. coli 173-25 prevented lysis of the cells whereas casein hydrolysate and a number of DAP analogs would not. Two compounds, [alpha]-methyldiaminopimelic acid and [beta]-hydroxydiaminopimelic acid could substitute for DAP and also prevent disruption of the cell. Lanthionine and cystathionine, but not [beta]-methyllanthionine, prevented lysis of the cell but would not substitute for DAP as the growth requirement for E. coli 173-25. It appears that DAP is found only in the cell-walls of E. coli 173-25, and that lysis of the cell occurs because synthesis of the cell-wall stops or incomplete cell-wall is made when DAP becomes limiting.