228 A. GAREN AND L. M. KOZLOFF 



reverses this inhibition and greatly stimulates the myosin ATPase. Simi- 

 larly, K"*" and NH4''" allow the infection of the host ceU by T2 in the presence 

 of EDTA, although no infection occurs in the presence of Na"*" or Li"*". 



<* Taken from Kielley and associates (1956). The values are for the amount of inorganic 

 phosphate liberated under their test conditions: 0.001 31 EDTA, pH 7.7, monovalent 

 cation 0.3 M. 



^ The values given represent the nimiber of infective centers ( X 10~^) formed in the 

 presence of EDTA (0.01 M) and 0.6 M salt (Kozloff, 1958). 



The effect of sodium EDTA on the morphological alteration of the phage 

 tail during interaction with the cell wall is shown in Fig. lOd. In this micro- 

 graph, the three particles that can be seen have lost their tail fibers, and the 

 tail core has become visible. However, the degree of contraction in the presence 

 of the sodium" EDTA is markedly less than that observed when sodium 

 EDTA is absent (see Fig. 8 and Fig. 10c). In the presence of sodium EDTA, 

 the proximal tail protein contracts to 70 % of its length as compared 

 to the 50 % contraction in the absence of sodium EDTA. The relative 

 thicknesses of the proximal tail proteins is in agreement with these differ- 

 ences in shortening. It can be concluded that sodium EDTA inhibits the 

 rate and degree of contraction of the proximal tail protein, similar to its 

 action on actomyosin, 



B. Action of Phage Enzyme on the Host CeU Wall 



When the phenomena of "lysis-from- without" was described by Delbriick 

 (1940b), it seemed likely that the rapid lysis of susceptible cells by large 

 numbers of phage particles was probably due to lytic activity in the phage 

 particles. Anderson (1945) showed that a lytic substance could be released 

 from phage by irradiation. Later, Weidel (1951) assumed that the decomposi- 

 tion of the bacterial cell waU which he observed was the result of the action 



