The Journal of Biological Physics and Chemistry

The influence of pH on thermal and hydrodynamic properties of DDVI phage and on DNA ejection from phage induced by bacterial membrane fragments

M. Khvedelidze¹, T. Mdzinarashvili¹, A. Ivanova¹, M. Tediashvili², D. Tushishvili² and G. Mrevlishvili¹

¹ Chair of Physics of Macromolecules,Department of Physics, Iv. Javakhishvili State University, 3 Chavchavadze Ave, 0128 Tbilisi, Georgia
² Eliava Institute of Bacteriophage, Microbiology and Virology, 3 Gotua St, Tbilisi, Georgia

The thermal and hydrodynamic properties of DDVI phage under the influence of pH, which was chosen as an external parameter to be varied, were studied. It was shown that over a wide pH range (pH 5 - 10) the phage particle conserves its structural organization. The experimental data also show that the DNA leaves the phage head completely. It was found that at pH values outside this range the DNA was not released from the phage capsid into the solvent. The first steps of phage-bacteria interaction (phage adsorption on membrane fragments and DNA ejection from the phage) in a model system consisting of DDVI phage and membrane fragments of its bacterial host cell have been studied. Membrane fragments from E. coli with an active receptor system were obtained by ultrasonic disintegration (sonification). Using a viscometric method, DNA ejection from the phage capsid induced by membrane fragments was observed. The viscometric investigations were carried out under alkaline conditions, because in this case less aggregation of the bacterial membrane fragments was observed. It was demonstrated that the specific viscosity of both phage and the membrane fragments is almost zero. The specific viscosity increases with time (i.e. a kinetic process) only in the case of the phage-membrane fragments complex. The kinetic process in turn results in phage adsorption on the bacterial membrane fragments and DNA ejection from the phage into the solvent.

Keywords: adsorption, bacterial membrane fragments, calorimetry, DNA ejection, pH, phage, viscometry