EFFECT OF PHYSICAL AND CHEMICAL AGENTS 55 



somewhat more resistant than the large phages but much more 

 sensitive than the small phages. T. F. Anderson and Doermann 

 (1952a) applied this information in studies of the intracellular 

 development of phage T3 (Chapter XI). 



Anderson and Doermann (1952b) also tested the effect of 

 sonic vibration on phage that had been inactivated w^ith anti- 

 body. Phage T3 was treated with anti-T3 serum to a phage 

 survival of 10~^. After dilution, treatment of the neutralized 

 phage with sonic vibrations resulted in a 40-fold increase in 

 phage titer, presumably due to breaking of the bonds linking 

 antibody molecules to phage particles. 



9. Surface Denaturation 



Proteins are rapidly denatured when subjected to the un- 

 balanced forces existing at gas-liquid or liquid-liquid interfaces, 

 and physiologically active proteins such as enzymes and toxins 

 are thus inactivated. The first quantitative study of this 

 phenomenon with phages was made by Campbell-Renton (1942). 

 She found that all the phages tested were rather rapidly in- 

 activated when aqueous solutions were vigorously shaken in air. 

 In one experiment for which detailed data are given the in- 

 activation was first order to a survival of less than lO""*, except for 

 an initial lag of 25 minutes due to the presence of 100 /xg. per ml. 

 of peptone in the medium. The inactivation could be greatly 

 retarded by increasing the concentration of peptone, and ac- 

 celerated by omitting peptone. 



The same phenomenon was studied by Adams (1948) with the 

 seven coliphages of the T group. Surface inactivation occurred 

 very rapidly in a chemically defined diluent at the gas-liquid 

 interfaces formed by bubbling or shaking with air or nitrogen. 

 Under conditions of vigorous shaking the inactivation kinetics 

 were first order with a low temperature coefficient, as might be 

 expected of a reaction in which the rate-limiting step is diffusion 

 of the virus particles into the region of the interface. The re- 

 action rate was nearly independent of pH over most of the 

 stability range of the phages but was greatly accelerated near the 



