The Accumulation of Nucleotides by Escherichia coli Strain 26-26

Abstract

SUMMARYEscherichia coli strain 26-26 (a mutant requiring lysine for growth) releases into the medium diaminopimelic acid, lipomucoprotein and nucleotides, including flavins, when grown with suboptimal concentrations of lysine. Cytidine diphosphate glycerol, cytidine diphosphate ribitol and a uridinelinked mucopeptide containing N-acetylmuramic acid, glutamic acid, mesodiaminopimelic acid and alanine were identified among the nucleotides extracted from the medium. Similar uridine diphosphate-linked mucopeptides were isolated from extracts made from bacteria at various stages of growth. In addition, uridine diphosphate-linked mucopeptides were isolated from bacterial extracts which were found to contain muramic acid and lysine but no diaminopimelic acid. The possible role of these compounds as precursors of cell wall structures is discussed.

THE CHEMISTRY AND ELECTRON MICROSCOPY OF AN EXTRACELLULAR LIPOPOLYSACCHARIDE FROM ESCHERICHIA COLI

“…A certain type of lysine-requiring mutant of Escherichia coli is lacking in the enzyme which decarboxylates diaminopimelic acid to lysine. When grown under lysine-limiting conditions, such mutants excrete large amounts of diaminopimelic acid (Work & Denman, 1953;Casida, 1956) and, to a lesser extent, flavines, nucleotides, lipids, polysaccharides and protein (Meadow, 1958;Lilly, Clarke & Meadow, 1963;Municio, Diaz & Martinez, 1963. A peculiar biphasic type of growth occurs under these conditions, and the accumulation of products in the culture fluid only commences when primary growth ceases owing to depletion of lysine.…”

Diaminopimelic Acid Synthesis in Cultures of an Escherichia coli Double Auxotroph: Effects of Cultural Conditions

“…Escherichia coli ATCC 13002 grown in shaken culture exhibits a diphasic-type growth curve in which a stationary phase of about 20 h follows the initial (presumably exponential) growth period and precedes a second growth phase. Diphasic growth has been reported in DAP-producing cultures of E. coli mutants singly auxotrophic for lysine by Angulo et al (1960), Lilly et al (1963) and Bishop & Work (1965) who suggest that diphasic growth is related to the formation of DAP. During the course of cultivation in stirred and aerated fermenters, these workers observed that DAP production started soon after completion of the exponential phase of growth and continued at a steady rate in the second growth phase until there was no further increase in the opacity of the culture.…”

“…In our comparable experiment, employing shaken cultures, the production of DAP had reached a good level (at 43 h) before the onset of secondary growth, less D A P synthesis being observed in this later phase. If it is correct to assign this secondary growth to the development of lysine-independent forms as suggested by Angulo et al (1960) and Lilly et al (1963), some utilization of DAP might be anticipated. The partial reversal at 70 h of the trend, observed at 20 and 43 h, for the yield of D A P (mg/mg cell mass) to decrease in shaken cultures of E. coli ATCC 13002 with increasing lysine concentration may be most reasonably ascribed to such secondary growth.…”

Diaminopimelic Acid and Lysine Auxotrophs of Pseudomonas aeruginosa 8602

“…The only differences detected between these mutants and the parent strain were the absence of DAP decarboxylase activity, their obligate requirement for lysine, which was not replaced by DAP, and their accumulation of DAP in the growth medium and intracellularly when grown in lysine-deficient media. The accumulation of DAP by organisms deficient in or lacking DAP decarboxylase has been shown in Escherichia coli (Lilly et al 1963) and more recently in Staphylococcus aureus (Barnes, Bondi & Moat, 1969). This accumulation probably results from the mode of control of DAP and lysine metabolism in these organisms.…”