Figure 3.

Effect of two kinds of NO donors, inactivated NO donor and NO metabolite, on Shiga toxin production in the deleted norV‐type EHEC under anaerobic conditions. EHEC EDL933 grown overnight were diluted with LB broth containing various concentrations of NO donors [NOC12 (a) or Spermine‐NONOate (Sper/NO) (a)], inactivated NO donor (b) or NO metabolite (c, d) and then grown statically for 18 hr at 37°C under anaerobic conditions. The culture supernatant fractions and cell‐associated fractions from the culture of EHEC strains were collected. The cell‐associated fractions were analyzed by Immunoblot analysis using anti‐Stx1 antiserum and anti‐RNA α antibody as an internal control. The culture supernatant fractions were analyzed by Immunoblot analysis using anti‐Stx2 antiserum. The relative amounts of Stx1 and Stx2 were quantified by densitometry and normalized to internal control RNA α . Data are the means ± standard deviations of values from four experiments. *p < 0.01; N. S., not significant.