Methionineless Death in Escherichia coli

Abstract

Methioninp auxotrophs of strains derived from Escherichia coli 15 lose their colony-forming ability when deprived of this amino acid. Late addition of methionine to liquid cultures did not restore plating efficiency but permitted growth of surviving cells. This phenomenon, termed methionineless death (mid), was not observed with methionine auxotrophs of E. coli strains B, W, or K12, nor was a similar amino acidless death observed with corresponding auxotrophs of E. coli 15 for arginine, tryptophan, proline, isoleucine, and leucine. Mid was not dependent upon the genetic site determining methionine auxotrophy, nor did it affect the decarboxylation of methionine or the stability of methionyl-transfer ribonucleic acid synthetase activity of starved cells. Death was not altered by the presence of spermine or spermidine but was abolished by the methionine analogue, a-methylmethionine. Simultaneous starvation of another amino acid in a multiple auxotroph also significantly reduced mid, suggesting a possible role of protein synthesis. The onset of mid is correlated with a lower net increase of deoxyribonucleic acid. 100 AM and the missing growth requirements were added. The incubation was continued, and at various 1168

Loss of Deoxyribonucleic Acid-Thymine During Thymine Starvation of Escherichia coli

“…Portions (1 ml) of the filtrates were counted in 10 ml of scintillation fluid (containing two volumes of toluene-phosphor and 1 volume of Triton X-100). The filters were washed and counted as described previously (4). The release of acid-soluble material was calculated as a percentage of the total amount of acid-insoluble labeled DNA present initially.…”

Exopolysaccharide defects cause hyper-thymineless death in Escherichia coli via massive loss of chromosomal DNA and cell lysis

“…In contrast to typically static responses to amino acid or RNA base starvation in E. coli (2,49), T-starvation leads to cell death, but not directly. The nature of the two-generations-long resistance phase, followed by the sudden shift to the RED phase (Fig.…”