Adsorption of bacteriophage on bacterial surface and on the surface of Hg drop** electrode

Summary

The influence of the ionic strength of the medium on the adsorption of bacteriophage T 2 to the surfaces of a mercury drop** electrode on one hand and ofbacteria E. coli B on the other hand was studied. The adsorption on the mercury surface was determined by measurement of the differential capacity of the electrode double layer, the adsorption to bacteria was estimated from the decrease of free phage particles in a bacterial suspension with time. The adsorption to the mercury electrode increases with increasing ionic strength of the medium, but adsorption to the surface of bacteria increases at first, has a maximum at concentrations between 0,1 to 0,5 M and decreases with further increase of ionic strength. The decrease of adsorption of phage to the bacterial surface is assumed to be caused by the blocking of specific sites on the bacterial surface by adsorbed ions which sterically prevent the adsorption of the phage. Such specific sites are not present on the electrode surface, therefore adsorption increases further with increasing ionic strength probably due to the neutralization of surface charges of the phage and of the electrode. The saturated surface-concentration of the phageγ _s was calculated from the dependence of the differential capacity on the concentration. It is concluded fromγ _s value obtained that the phage particles are scattered with wide intervals on the electrode surface with a degree of coverage of approximately 1∶40.