Abnormal growth of polyamine-deficient Escherichia coli mutant is partially caused by oxidative stress-induced damage

• Published in: Archives of biochemistry and biophysics Vol. 418; no. 2; pp. 125 - 132
• Main Authors: Jung, Il Lae, Oh, Tae Jeong, Kim, In Gyu
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-10-2003
• Subjects: Abnormal growth; Amino Acids - classification; Amino Acids - metabolism; Chloromethyl-2 ′,7 ′-dichlorofluorescin diacetate; Escherichia coli; Escherichia coli - cytology; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli - metabolism; Gene Expression Regulation, Bacterial - physiology; Mutation; Oxidative stress; Oxidative Stress - physiology; Oxygen - metabolism; Polyamine; Polyamines - metabolism; Abnormal growth; Oxidative stress; Polyamine; Chloromethyl-2 ′,7 ′-dichlorofluorescin diacetate; Escherichia coli
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/j.abb.2003.08.003

Polyamines participate in numerous cellular processes and are required for normal cell growth in
Escherichia coli. In this study, we constructed a new polyamine-deficient
E. coli mutant and investigated the physiological function of polyamines during normal aerobic growth conditions. We showed that the requirement for sulfur-containing, branched chain, and aromatic amino acids, which was exhibited in the
sodA sodB double mutant faced with severe oxidative stress, was also true of the polyamine-deficient mutant during normal aerobic cell growth. Sorbitol, sucrose, mannose, 1,2-dihydroxybenzene-3,5-disulfonic acid (Tiron), an antioxidant that functions as an oxygen radical scavenger including
O
2
−, and thiamine partially relieved the cell growth defect caused by polyamine depletion in a dose-dependent manner. As was the case for the cells treated with paraquat, the mutant had an elongated shape compared with the polyamine-proficient wild type. Decreased aeration also relieved the cell growth defect of the polyamine-deficient mutant. Finally, we confirmed that chloromethyl-2
′,7
′-dichlorofluorescin diacetate (DCFH-DA), which is oxidized in a fluorescent product in the presence of various oxidants, also fluoresce in the polyamine-deficient cells. These results showed that abnormal growth of the polyamine-deficient
E. coli mutant results partially from oxidative stress-induced damage and the mutant thus exhibits the requirement for antioxidant or specific nutritional amino acid during normal aerobic growth.