Department of Physics, Umeå University, Umeå, Sweden.
Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden.
J Biophotonics. 2022 Aug;15(8):e202200081. doi: 10.1002/jbio.202200081. Epub 2022 May 29.
Bacterial spores are highly resistant to heat, radiation and various disinfection chemicals. The impact of these on the biophysical and physicochemical properties of spores can be studied on the single-cell level using optical tweezers. However, the effect of the trapping laser on spores' germination rate is not fully understood. In this work, we assess the impact of 1064 nm laser light on the germination of Bacillus thuringiensis spores. The results show that the germination rate of spores after laser exposure follows a sigmoid dose-response relationship, with only 15% of spores germinating after 20 J of laser light. Under anaerobic growth conditions, the percentage of germinating spores at 20 J increased to 65%. The results thereby indicate that molecular oxygen is a major contributor to the germination-inhibiting effect observed. Thus, our study highlights the risk for optical trapping of spores and ways to mitigate it.
细菌孢子具有很强的耐热、耐辐射和耐各种消毒化学品的能力。使用光学镊子可以在单细胞水平上研究这些因素对孢子的生物物理和物理化学特性的影响。然而，捕获激光对孢子发芽率的影响还不完全清楚。在这项工作中，我们评估了 1064nm 激光对苏云金芽孢杆菌孢子发芽的影响。结果表明，激光照射后孢子的发芽率遵循 S 型剂量反应关系，只有 20J 的激光照射后才有 15%的孢子发芽。在厌氧生长条件下，20J 时发芽孢子的百分比增加到 65%。结果表明，分子氧是观察到的抑制发芽作用的主要原因。因此，我们的研究强调了光学捕获孢子的风险及其缓解方法。
