Oyane Ikuko, Takeda Tomo, Oda Yasunori, Sakata Takashi, Furuta Masakazu, Okitsu Kenji, Maeda Yasuaki, Nishimura Rokuro
Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
Ultrason Sonochem. 2009 Apr;16(4):532-6. doi: 10.1016/j.ultsonch.2009.01.001. Epub 2009 Jan 13.
The effects of 200 kHz ultrasonic irradiation on DNA or RNA formation and membrane permeability of yeast cells were investigated by flow cytometry and compared with those of (60)Co gamma-ray radiation. Colony counting analyses were also performed for comparison. It was observed that the colony-forming activity of yeast cells was not affected by small doses of ultrasonic irradiation, but was closely related to the amounts of sonolytically formed hydrogen peroxide at concentrations of more than 80 microM. On the other hand, gamma-rays directly retarded colony-forming ability in addition to the effects of radiolytically formed hydrogen peroxide. The results obtained by flow cytometry also indicated that the amounts of DNA or RNA formed decreased with an increase in ultrasonic irradiation time without any threshold. These results indicated that flow cytometry can show early growth activities, but that colony counting analyses are insufficient to evaluate continuous and quantitative changes in these activities. In addition, by analyzing the amounts of DNA or RNA formed in the presence of the same amount of hydrogen peroxide, it was found that DNA or RNA formation behavior in the presence of hydrogen peroxide with no irradiation was similar to that following ultrasonic irradiation. These results suggested that similar chemical effects due to the formation of hydrogen peroxide were produced during ultrasonic irradiation. In addition, physical effects of ultrasound, such as shock wave, hardly contributed to cell inactivation and cell membrane damage, because relatively high frequency ultrasound was used here. In the case of gamma-ray radiation, direct physical effects on the cells were clearly observed.
通过流式细胞术研究了200 kHz超声辐照对酵母细胞DNA或RNA形成及膜通透性的影响，并与（60）Coγ射线辐射的影响进行了比较。还进行了菌落计数分析以作比较。观察到小剂量超声辐照不影响酵母细胞的集落形成活性，但在浓度超过80 microM时，其与超声分解产生的过氧化氢量密切相关。另一方面，γ射线除了辐射分解产生的过氧化氢的影响外，还直接抑制集落形成能力。流式细胞术获得的结果还表明，DNA或RNA的形成量随超声辐照时间的增加而减少，且无任何阈值。这些结果表明，流式细胞术可以显示早期生长活性，但菌落计数分析不足以评估这些活性的连续和定量变化。此外，通过分析在相同量过氧化氢存在下形成的DNA或RNA的量，发现未辐照时过氧化氢存在下的DNA或RNA形成行为与超声辐照后的相似。这些结果表明，超声辐照期间由于过氧化氢的形成产生了类似的化学效应。此外，由于这里使用的是相对高频的超声，超声的物理效应，如冲击波，对细胞失活和细胞膜损伤几乎没有贡献。在γ射线辐射的情况下，可以清楚地观察到对细胞的直接物理效应。
