Ushakov V L, Bartenev D Iu, Borisiuk M A, Beliaev I Ia, Alipov E D, Shcheglov V S
Moscow Technical University, Moscow, Russia.
Biofizika. 2001 Mar-Apr;46(2):265-70.
The sensitivity of the anomalous time dependence of viscosity to the concentration of the DNA-protein complexes (DNA + histone-like proteins of bacteria or, in other words, the genome) such as chromatin and the conformations of these complexes in lysates of E. coli AB1157 cells were studied. A linear region of the anomalous viscosity time dependence on the concentration of E. coli cells was found in which the interactions between single DNA-protein complexes can be neglected. The response of the genome of E. coli to ethidium bromide at concentrations of 0.0003-3 mg/ml was studied. Significant differences in the effect of ethidium bromide on E. coli cells in the stationary and logarithmic growth phases were found. The effect of heating cell lysates, the molar concentration of NaCl in lysates, and the addition of proteins into lysates on the parameters of the anomalous viscosity time dependence was studied. It was shown that proteins do not contribute significantly to the effect of anomalous viscosity time dependence. The results obtained confirm that the method is sensitive to changes in the conformational state of the genome of E. coli cells.
