CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Institute of Intelligent Agriculture, Institute of Intelligent Machines, Hefei Institutes of Physical Science, Chinese Academy of Sciences (CAS), Hefei 230031, China.
CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Institute of Intelligent Agriculture, Institute of Intelligent Machines, Hefei Institutes of Physical Science, Chinese Academy of Sciences (CAS), Hefei 230031, China; Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China.
Sci Total Environ. 2022 Sep 10;838(Pt 4):156576. doi: 10.1016/j.scitotenv.2022.156576. Epub 2022 Jun 7.
Cold atmospheric plasma (CAP) possesses the ability of high-efficiency disinfection. It is reported that mixtures of reactive oxygen species (ROS) including OH, O, O and HO generated from CAP have better antimicrobial ability than mimicked solution of mixture of single ROS type, but the reason is not clear. In this study, CAP was applied to treat yeasts in water in order to investigate the fungal inactivation efficiency and mechanism. The results showed that plasma treatment for 5 min could result in >2-log reduction of yeast cells, and application of varied ROS scavengers could significantly increase the yeast survival rate, indicating that OH and O played the pivotal role in yeast inactivation. Moreover, the synergistic effect of O with other plasma-generated ROS was revealed. O could diffuse into cells and induce the depolarization of mitochondrial membrane potential (MMP), and different levels of MMP depolarization determined different cell death modes. Mild damage of mitochondria during short-term plasma treatment could lead to apoptosis. For long-term plasma treatment, the cell membrane could be severely damaged by the plasma-generated OH, so a large amount of O could induce more depolarization of MMP, leading to increase of intracellular O and Fe which subsequently caused cell inactivation. O could also induce protein aggregation and increase of RIP1/RIP3 necrosome, leading to necroptosis. With participation of O, endogenous OH could also be generated via Fenton and Haber-Weiss reactions during plasma treatment, which potentiated necroptosis. Adding l-His could mitigate membrane damage, inhibit the drop of MMP and the formation of necrosome, and thus prevent the happening of necroptosis. These findings may deepen the understanding of plasma sterilization mechanisms and provide guidance for microbial killing in the environment.
冷等离子体（CAP）具有高效消毒的能力。据报道，CAP 产生的包括 OH、O、O 和 HO 在内的活性氧（ROS）混合物比模拟的单一 ROS 类型混合物具有更好的抗菌能力，但原因尚不清楚。在这项研究中，CAP 被应用于处理水中的酵母菌，以研究真菌失活动力学和机制。结果表明，等离子体处理 5 分钟可使酵母细胞减少>2 个对数级，而应用不同的 ROS 清除剂可显著提高酵母存活率，表明 OH 和 O 在酵母失活中起关键作用。此外，还揭示了 O 与其他等离子体产生的 ROS 的协同作用。O 可以扩散到细胞中并诱导线粒体膜电位（MMP）去极化，不同程度的 MMP 去极化决定了不同的细胞死亡模式。短期等离子体处理对线粒体的轻微损伤可导致细胞凋亡。对于长期等离子体处理，细胞膜可能会被等离子体产生的 OH 严重破坏，因此大量 O 可以诱导 MMP 更大程度的去极化，导致细胞内 O 和 Fe 的增加，从而导致细胞失活。O 还可以诱导蛋白质聚集和 RIP1/RIP3 坏死小体的形成，导致细胞坏死。在等离子体处理过程中，O 的参与还可以通过 Fenton 和 Haber-Weiss 反应产生内源性 OH，从而增强细胞坏死。添加 l-His 可以减轻膜损伤，抑制 MMP 下降和坏死小体的形成，从而防止细胞坏死的发生。这些发现可能加深对等离子体杀菌机制的理解，并为环境中微生物的杀灭提供指导。
