EFFECTS ON BACTERIA AND VIRUSES 727 



controls at 135 min after fertilization are 2% in the 2 -cell stage, 50% in the 

 4-cell stage, and 48% in the 8-cell stage, whereas those treated with o-iodo- 

 sobenzoate are 8% in the 4-cell stage and 92% in the 8-cell stage. Second, 

 there is no obvious disturbance in development, e.g., no evidence of animal- 

 ization, and the ciliated embryos inside their membranes appear to be nor- 

 mally active. Differentiation in Paracentrotus is thus less susceptible than in 

 Arbacia to o-iodosobenzoate. Higher concentrations of o-iodosobenzoate may 

 produce other effects on eggs but whether these actions are mediated through 

 SH group oxidation is not known. The eggs of Hemicentrotus pulcherrimus 

 and Urechis unicinctus elevated the fertilization membrane when incubated 

 for 10 min in 10 raM o-iodosobenzoate at pH 4 and then returned to normal 

 sea water (Isaka and Aikawa, 1963). It was suggested that the vitelline and 

 plasma membranes are connected by hydrogen bonds and that o-iodosoben- 

 zoate and other SH reagents react with SH groups in the plasma membrane, 

 weakening these bonds and allowing separation of the membranes. Move- 

 ments during cleavage have been supposed to involve contractile proteins 

 as in muscle, and threads formed from fibrous proteins obtained from Hemi- 

 centrotus eggs contract when metal ions (e.g., Mg++, Cu++, Cd++, etc.) are 

 added (Sakai, 1962). This contraction is blocked by 5 rsxM o-iodosobenzoate 

 and high concentrations of other SH reagents, indicating that SH groups 

 are necessary. 



EFFECTS ON BACTERIA AND VIRUSES 



The early interest in the antibacterial actions of iodine led Arkin (1911), 

 in connection with the pharmacological studies of Loevenhart and Grove 

 at Wisconsin, to investigate the effects of o-iodosobenzoate and related 

 compounds on various bacteria. Eberthella typhosa, E. coli, S. aureus, and B. 

 pyocyaneus are all killed by exposures of 24 hr to 1 mM at 37°, not surpris- 

 ingly. o-Iodoxybenzoate is even more potent, but o-iodobenzoate does not 

 kill even at 10 mM. Jahn (1914) found the growth of E. coli to be inhibited 

 by 0.38 mM o-iodosobenzoate, but not by 38 mM o-iodobenzoate, indicat- 

 ing the importance of the oxidative action and confirming the results in 

 animals. Chinard (1942) considered the possibility of using o-iodosoben- 

 zoate locally in infected wounds. He observed marked inhibition of the 

 growth of E. coli at 0.02 mM with eventual death of the bacteria in 72 hr, 

 and death of hemolytic streptococci at 0.38 mif. If the o-iodosobenzoate is 

 injected with these streptococci subcutaneously into mice, no infections are 

 seen, but all the control mice die. The flagellar activity of B. brevis is well 

 inhibited by 2 mM o-iodosobenzoate at 30 sec and maximally at 5 min 

 (De Robertis and Peluffo, 1951). Yeast is more resistant, since it requires 

 3.8 mM to inhibit the growth 50% (Loveless et al., 1954). No analyses at 

 all have been made of the sites or mechanisms of action. It is likely that 



