Effect of Some Nitrosative Agents on the Growth of <Emphasis Type="Italic">vgb</Emphasis>-bearing <Emphasis Type="Italic">Enterobacter aerogenes</Emphasis> Strains

The effect of transnitrosation intermediate between S-nitroso-N-acetylcysteine (NACysNO) and cysteine on the growth of vgb-bearing Enterobacter aerogenes was investigated using three parameters: the ratio of the specific growth rates, the inhibition zone, and α-amylase synthesis for the culture exposed to stressors to that of the same stressor-free cultures. The effect of NACysNO/cysteine on the growth of Enterobacter strains was distinctive as compared with the CysNO, NACysNO, and their combination. At a higher concentration (2 mM), the extents of inhibition based on the μ_{NACysNO/cysteine}/μ_{no stress} ratio for these cultures were 57%, 62%, and 68% for VHb-expressing, parental, and pUC9-harboring cells, respectively. The inhibition caused by 2 mM NACysNO in the presence of 1 mM cysteine in all bacterial strains was almost twofold that achieved by NACysNO alone. Based on the diameter of the inhibition zone and α-amylase productivity, the four compounds (NACysNO/Cysteine, CysNO, NACysNO, and their combinations) affected the E. aerogenes strains in a concentration-dependent and negative manner. This negative effect was lower in vgb-bearing than vgb-lacking strains. Thus, sulfur-to-sulfur transnitrosation was an efficient NO release and significantly (P < 0.05) affects the growth of Enterobacter strains, to a lesser extent in vgb-bearing strains.