Hydrogen peroxide causes Vibrio vulnificus bacteriolysis accelerated by sulfonyl fluoride compounds

Induction of bacteriolysis of Vibrio vulnificus cells by 10 mM hydrogen peroxide (H(2)O(2)) was analyzed. All Vibrio species examined, except for Vibrio hollisae, were lysed by 10 mM H(2)O(2). Bacteriophage induction was not the cause of H(2)O(2)-induced bacteriolysis. Autolysis is also known to cause bacteriolysis. VvpS protein is a serine protease of V. vulnificus essential for autolysis. vvpS mutant underwent H(2)O(2)-induced bacteriolysis in the same manner as the wild type. Protease inhibitors including serine protease inhibitors did not inhibit H(2)O(2)-induced bacteriolysis, which means that bacteriolysis is not due to autolysis. Unexpectedly, H(2)O(2)-induced bacteriolysis was accelerated by adding 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF) and phenylmethylsulfonyl fluoride which are serine protease inhibitors. The hydroxyl radical was generated by H(2)O(2)-AEBSF interaction. It was considered that H(2)O(2)-induced bacteriolysis was caused by the hydroxyl radical which was generated by Fenton reaction, and possibly mediated by AEBSF. Deferoxamine, an agent chelating ferric ion and Fenton reaction inhibitor, suppressed both H(2)O(2)-induced bacteriolysis and its acceleration by AEBSF. This suggests that both phenomena were Fenton reaction dependent, and hydroxyl radical generated by Fenton reaction caused bacteriolysis of V. vulnificus though the reason for high susceptibility of Vibrio species to hydroxyl radical is not known.