等离子体活化水对腐败希瓦氏菌杀菌效果及机理

为探究等离子体活化水（plasma activated water，PAW）对水产品中常见的腐败希瓦氏菌（Shewanella putrefaciens）的杀菌效果及其作用机制。本实验通过平板计数、荧光染色、扫描电子显微镜等方法，研究了PAW对Shewanella putrefaciens的杀菌作用以及对其细胞形态、细胞膜通透性、细胞膜电位和细胞内容物泄漏情况等指标的影响。结果表明：PAW能显著降低Shewanella putrefaciens的数量（P＜0.05），经等离子体放电120 s的活化水（PAW120）处理6.0 min后，菌落数对数值减少了7.44（lg（CFU/mL）），细菌形态发生皱缩和破裂，内膜和外膜通透性分别增加了989.31%和474.51%，胞内核酸、蛋白等大分子发生泄漏，电导率显著升高（P＜0.05）；傅里叶变换红外光谱分析结果显示，经PAW120处理后细菌细胞脂质和蛋白质结构发生变化。综上所述，PAW能够通过破坏细胞壁从而使细胞膜通透性增大、细胞内蛋白和核酸流出，最终导致细胞死亡。本研究可为PAW在水产品保鲜中的应用提供理论依据。

Inactivation Effect and Mechanism of Plasma Activated Water on Shewanella putrefaciens

In this study, the bactericidal effect and mechanism of plasma activated water (PAW) against Shewanella putrefaciens, a common microorganism found in aquatic products, were investigated by plate counting, fluorescence staining and scanning electron microscopy (SEM). The impact of PAW on cell morphology, cell membrane permeability, cell membrane potential and cell content leakage was examined. The results showed that the count of Shewanella putrefaciens was significantly decreased by PAW (P < 0.05). After 6.0 min of treatment with activated water from plasma discharge 120 s (PAW120), the colony count decreased by 7.44(lg (CFU/mL)), the cell morphology showed shrinkage and rupture, and the permeability of the inner and outer membranes increased by 989.31% and 474.51%, respectively. Moreover, intracellular macromolecules such as nucleic acids and proteins leaked out of the cells, and the electrical conductivity increased significantly (P < 0.05). The results of Fourier transform infrared (FTIR) spectroscopy showed that the structures of intracellular lipids and proteins were changed after PAW120 treatment. In conclusion, PAW could destroy the cell wall, and increase the permeability of the cell membrane, thereby leading to the leakage of intracellular nucleic acids and proteins and eventually cell death. This study provides a theoretical basis for the application of PAW in the preservation of aquatic products.