Matsumoto Nagomi, Hisatomi Osamu
Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-Cho, Toyonaka, Osaka, 560-0043, Japan.
Sci Rep. 2025 Jul 1;15(1):20848. doi: 10.1038/s41598-025-06596-4.
The growth rate of many microorganisms decreases when exposed to blue light (BL) at around 450 nm. This growth retardation is likely caused by the photosensitivity of endogenous photosensitizers, flavins, which absorb BL and generate reactive oxygen species (ROS) that cause inactivation and mutations of microorganisms. In this study, the effect of weak (0-0.12 mW/cm) 463 nm BL on E. coli (DH5α) cell proliferation was investigated. Surprisingly, BL of only 0.03 mW/cm reduced the DH5α colony number by 52%, and about 5% of cells (BL-resistant cells) formed colonies under 0.1 mW/cm BL. Five-generation subculturing suggested that the BL-resistant cells underwent mutation(s) and adapted to grow under a BL environment. Fewer superoxide anion radicals were generated by BL irradiation in BL-resistant cells than in control DH5α cells because of the lower amount of intracellular flavins in BL-resistant cells. Our data suggest that the main photosensitizer of 463 nm BL is flavins, and ROS generated by BL-activated flavins induces inactivation and mutation(s) of DH5α cells. BL-resistant mutant cells with low amounts of intracellular flavins may reproducibly be generated by mutation(s) and preferentially proliferate under BL conditions.
许多微生物在暴露于波长约450nm的蓝光（BL）时，其生长速率会降低。这种生长迟缓可能是由内源性光敏剂黄素的光敏性引起的，黄素吸收蓝光并产生活性氧（ROS），导致微生物失活和突变。在本研究中，研究了弱（0 - 0.12mW/cm）463nm蓝光对大肠杆菌（DH5α）细胞增殖的影响。令人惊讶的是，仅0.03mW/cm的蓝光使DH5α菌落数减少了52%，并且在0.1mW/cm蓝光下约5%的细胞（蓝光抗性细胞）形成了菌落。连续五代传代表明，蓝光抗性细胞发生了突变并适应在蓝光环境下生长。由于蓝光抗性细胞内黄素含量较低，蓝光照射在蓝光抗性细胞中产生的超氧阴离子自由基比对照DH5α细胞少。我们的数据表明，463nm蓝光的主要光敏剂是黄素，蓝光激活黄素产生的ROS诱导DH5α细胞失活和突变。细胞内黄素含量低的蓝光抗性突变细胞可能通过突变可重复产生，并在蓝光条件下优先增殖。
