摘要
利用介电谱方法详细研究了Cu2+、Zn2+、Cd2+、Pb2+、Al3+、Ni2+等金属离子以及阳离子表面活性剂CTAB(十六烷基三甲基溴化铵)对典型的真核细胞——酵母细胞介电性质的影响。在时间变化和浓度变化的情况下,对上述体系在40Hz～110MHz宽频范围进行了介电测量,Cole-Cole拟合确定了介电参数,定性讨论了不同试剂的时间和浓度的各种作用效果。通过无作用的对照细胞和有离子作用的作用组细胞10小时内的介电谱图比较发现,Cu2+、Pb2+及CTAB对酵母细胞介电行为的影响是以孵化时间依赖的方式发生;对有时间作用的三者选用不同的浓度进行作用,结果发现Cu2+及CTAB对酵母细胞的作用同样是以浓度依赖的方式进行,而不同浓度的Pb2+的作用效果接近。进一步,根据酵母细胞的结构特点采用双壳介电模型,理论计算了相参数,并结合细胞生理学知识对细胞受金属离子或特殊试剂作用后的相参数变化原因给予了解释;给出了金属离子,特别是Cu2+以及CTAB与酵母细胞作用的可能机制。此外,模拟了实验条件下细胞悬浮液中各组成相参数对介电谱的依存关系,给出了一些有益的暗示:介电增量主要受细胞膜介电常数和细胞体积分数影响;特征频率f0与液泡膜介电常数以及细胞质的电导率等物理参数有关;而液泡内电导率支配高频的弛豫行为。这些模拟将对酵母细胞介电实时监测技术的实现提供基础参考。
The paper repot mainly the results of the effects of Cu2＋, Zn2＋, Cd2＋, Pb2＋, Al3＋, Ni2＋ and CTAB（cetyltrimethylammonium bromide） on dielectric properties of yeast cell suspensions. In this study, dielectric measurements were carried out with different incubation time and different concentrations of the chemical agents mentioned above over the broad frequency range of 40 Hz-110 MHz. Cole-Cole equation was employed to fit the dielectric spectra to obtain the dielectric parameters, which demonstrated different effects of different agents in qualitative. By comparing the dielectric spectra of control cells and treated cells incubated with above ions and CTAB, we found that the effect of Cu2＋, Pb2＋ and CTAB was in a manner of time-dependent. Further experiment with different concentrations of Cu2＋, Pb2＋ and CTAB was carried out in the same way as above. The results showed that the effect of Cu2＋ and CTAB was also in a concentration-dependent manner, whereas the effect of Pb2＋ with different concentrations was almost the same. In order to give quantitative analysis, we chose the double-shell model to simulate the experimental data curves according to the yeast cell structure. Combining the phase parameters calculated and the knowledge of yeast cells physiology, we gave some explanations to the change of the phase parameters and predicted the effect mechanism of Cu2＋ and CTAB on yeast cells. The simulations Of the dependence of phase parameters with the dielectric spectra revealed that dielectric increment mainly depends on the variety of the cell plasma membrane permittivity and cell volume concentrations; characteristic frequency mainly depends on the variety of the permittivity of vacuole membrane and conductivity of cytoplasma, and conductivity of vacuole interior mainly effect the dielectric behavior of high frequency. These simulation results will give some basic reference to the realization of real-time monitoring technique.
出处
《生物物理学报》
CAS
CSCD
北大核心
2008年第5期348-360,共13页
Acta Biophysica Sinica
基金
国家自然科学基金项目(20673014)~~
关键词
介电谱
酵母细胞
金属离子
CTAB
双壳模型
介电解析
Dielectric spectroscopy
Yeast cell
Metal ions
CTAB
Double shell model
Dielectric analysis
