Castellarnau M, Errachid A, Madrid C, Juárez A, Samitier J
Nanobioengineering Research Laboratory, Institut de BioEnginyeria de Catalunya (IBEC), Barcelona, Spain.
Biophys J. 2006 Nov 15;91(10):3937-45. doi: 10.1529/biophysj.106.088534. Epub 2006 Sep 1.
In this study we report on an experimental method based on dielectrophoretic analysis to identify changes in four Escherichia coli isogenic strains that differed exclusively in one mutant allele. The dielectrophoretic properties of wild-type cells were compared to those of hns, hha, and hha hns mutant derivatives. The hns and hha genes code respectively for the global regulators Hha and H-NS. The Hha and H-NS proteins modulate gene expression in Escherichia coli and other Gram negative bacteria. Mutations in either hha or hns genes result in a pleiotropic phenotype. A two-shell prolate ellipsoidal model has been used to fit the experimental data, obtained from dielectrophoresis measurements, and to study the differences in the dielectric properties of the bacterial strains. The experimental results show that the mutant genotype can be predicted from the dielectrophoretic analysis of the corresponding cultures, opening the way to the development of microdevices for specific identification. Therefore, this study shows that dielectrophoresis can be a valuable tool to study bacterial populations which, although apparently homogeneous, may present phenotypic variability.
在本研究中，我们报告了一种基于介电泳分析的实验方法，用于识别四种仅在一个突变等位基因上存在差异的大肠杆菌同基因菌株的变化。将野生型细胞的介电泳特性与hns、hha和hha hns突变衍生物的介电泳特性进行了比较。hns和hha基因分别编码全局调节因子Hha和H-NS。Hha和H-NS蛋白调节大肠杆菌和其他革兰氏阴性细菌中的基因表达。hha或hns基因中的突变会导致多效性表型。已使用双壳长椭球体模型来拟合从介电泳测量中获得的实验数据，并研究细菌菌株介电特性的差异。实验结果表明，通过对相应培养物的介电泳分析可以预测突变基因型，为开发用于特异性识别的微器件开辟了道路。因此，本研究表明，介电泳可以成为研究细菌群体的有价值工具，这些细菌群体虽然表面上是同质的，但可能存在表型变异性。
