Thiouridine residues in tRNAs are responsible for a synergistic effect of UVA and UVB light in photoinactivation of Escherichia coli

• Published in: Environmental microbiology Vol. 19; no. 2; pp. 434 - 442
• Main Authors: Probst‐Rüd, Sandra, McNeill, Kristopher, Ackermann, Martin
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.02.2017
• Subjects: E coli; Escherichia coli; Escherichia coli - genetics; Escherichia coli - radiation effects; Microbial Viability - radiation effects; Microorganisms; Radiation Tolerance; RNA, Transfer - chemistry; RNA, Transfer - radiation effects; Sunlight; Thiouridine - chemistry; Ultraviolet Rays
• ISSN: 1462-2912; 1462-2920
• DOI: 10.1111/1462-2920.13319

Summary Since different wavelengths of light impact different cellular targets, microorganisms exposed to natural sunlight experience a combination of multiple stressors. In order to better understand the effects of sunlight on microorganisms we, therefore, need to understand how different wavelength act alone and in combination. Here, we describe a synergistic effect between UVA and UVB irradiation on viability of Escherichia coli bacteria. To investigate the basis of this synergistic effect we analysed mutant strains that were obtained through selection for increased resistance to combined UVA and UVB. By identifying and reconstructing genetic changes in the resistant strains we provide evidence that UVA‐absorbing thiouridine residues in tRNAs are the key to the synergistic effect. Our study provides insights into how naturally occurring combinations of stressors can interact, and points to new ways for controlling microbial populations.