Faculty of Applied Life Science, Nippon Veterinary and Life Science University, Musashino, Tokyo, Japan.
Curr Microbiol. 2022 Mar 2;79(4):120. doi: 10.1007/s00284-022-02817-5.
To clarify the lethal injury related to the inactivation of Saccharomyces pastorianus cells by low-pressure carbon dioxide microbubble (COMB) treatment, surviving number, leakage of nucleic acids and proteins, fluorescence polarisation (FP) of the cell membrane, activity of alkaline phosphatase (AP), intracellular pH (pH), mitochondrial membrane potential (MMP), cell surface hydrophobicity (CSH) and oxidative stress of S. pastorianus treated with COMB at various temperatures were measured. The number of surviving S. pastorianus cells decreased below the detection limit after COMB treatment at temperatures of 40, 45 and 50 ℃, inducing a 2-log reduction at 35 ℃. The S. pastorianus cells treated with COMB at temperatures above 40 ℃ showed an increase in FP and leakage of nucleic acids and proteins. The AP in S. pastorianus cells treated with COMB at a temperature of 35 ℃ was also activated but inactivated at temperatures above 40 ℃. Furthermore, the decrease in pH and MMP and the increase in CSH of S. pastorianus were caused by COMB treatment at temperatures above 35 ℃. Oxidative stress in S. pastorianus cells was also increased by COMB treatment without warming but decreased at temperatures above 35 ℃. Our results lead us to infer that the type of cell injury in S. pastorianus induced by COMB treatment differed from that caused by the treatment temperature and that the lethal injury was enzyme inactivation.
为了阐明低压二氧化碳微泡（COMB）处理对酿酒酵母细胞失活的致死损伤，测量了不同温度下 COMB 处理后酿酒酵母的存活数、核酸和蛋白质泄漏、细胞膜荧光偏振（FP）、碱性磷酸酶（AP）活性、细胞内 pH（pH）、线粒体膜电位（MMP）、细胞表面疏水性（CSH）和氧化应激。在 40、45 和 50℃的 COMB 处理后，酿酒酵母的存活数降至检测限以下，在 35℃时诱导 2 对数减少。在 40℃以上温度下用 COMB 处理的酿酒酵母细胞表现出 FP 的增加和核酸和蛋白质的泄漏。在 35℃下用 COMB 处理的酿酒酵母细胞中的 AP 也被激活，但在 40℃以上的温度下失活。此外，在 35℃以上温度下用 COMB 处理会导致 pH 和 MMP 的降低以及 CSH 的增加。COMB 处理没有升温也会导致酿酒酵母的氧化应激增加，但在 35℃以上的温度下会降低。我们的结果表明，COMB 处理诱导的酿酒酵母细胞损伤类型不同于处理温度引起的损伤类型，致死损伤是酶失活。
