578 5. QUINONES 



EFFECTS ON VIRUS AND PHAGE 



There is little doubt that quinones can inactivate viruses and inhibit 

 their proliferation; the interesting question is whether they can do this 

 specifically to any degree, that is, without simultaneous severe depression 

 of the host cells. Studies in which virus or phage suspensions are incubated 

 with the quinones and later placed in contact with the host cells indicate 

 the reaction of the quinones with virus or phage protein, and do not provide 

 information on the metabolic reactions associated with the proliferative 

 process. p-Benzoquinone at 1 mM, for example, completely inactivates 

 psittacosis virus (Burney and Golub, 1948) and influenza A virus (Wagner, 

 1951), but this is only an expression of the reaction of the quinone with 

 virus SH groups or the oxidation of such groups; indeed, cysteine not only 

 protects against the quinone but can restore some infectivity in the influenza 

 virus after inactivation. Hall et al. (1951) make a very complete investi- 

 gation of the effects of eight quinones on ten common phages. Streptococcal 

 phage, enterophage, and coliphage 24B are generally the most susceptible 

 and often are inactivated partially by concentrations as low as 0.003- 

 0.02 mM, although complete inactivation requires concentrations greater 

 than 0.3 mM in all cases. Toluquinone and 5-methoxytoluquinone are the 

 most potent inactivators, while the naphthoquinones are not very effec- 

 tive; menadione, for example, at 2.8 mM has no effect on four phages and 

 only moderately inactivates the others, whereas toluquinone inactivates 

 50% at a mean concentration of around 0.15 mM. Since the phages were 

 incubated with the quinones for several hours, the inactivation does not 

 imply a rapid reaction with phage protein, and it is only surprising that 

 some of the quinones have so little effect on phages which from other data 

 contain SH groups. Sery and Furgiuele (1961) have more recently conducted 

 similar studies on the herpes simplex virus, except that the incubation in- 

 terval was only 1 hr (see accompanying tabulation). In contrast to the 



