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Figure 6
Effect of NO exposure on Vvprx3 expression and VvPrx3 protein. (a) Total RNA was isolated from wild-type cells grown aerobically to an A600 of 0.5 after exposure to various concentrations of PLGA–PEI nanoparticles (PPNPs) or NO/PPNPs for 20 min. PPNPs were used as blank nanoparticles. The iscR and prx3 mRNA levels were determined by qRT-PCR analyses, and the iscR and prx3 mRNA levels in the wild type exposed to 0.2%(w/v) PPNPs were set to 1. Error bars represent the standard deviation (SD). *, P < 0.05; **, P < 0.005. (b) VvPrx3 (C73S) was incubated with NO/PPNPs for the times shown. A total of 3.3 µM NO accumulated in the reaction mixture per hour. The reaction was terminated by adding 2.5 mM iodoacetamide to prevent nonspecific disulfide bonds. Aliquots were taken from the reaction mixture and loaded onto SDS–PAGE under reducing conditions (DTT +) or nonreducing conditions (DTT −). (c) Survival of V. vulnificus strains in the presence of NO stress. Wild-type bacteria (WT) or prx3-deleted bacteria (prx3) were transformed with the empty expression vector pJK1113 or the functional prx3-containing vector pJK1303. Well grown bacterial cells were exposed to NO/PPNPs for the times shown and viable cells were counted as colony-forming units (CFU) on LBS agar plates. Error bars represent the standard deviation (SD). *, P < 0.05; **, P < 0.005.

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