Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6124225 | Journal of Infection and Chemotherapy | 2012 | 6 Pages |
Abstract
We studied the protein amount and activity of the major virulence factors hemolysin, cysteine protease streptococcal pyrogenic exotoxin B (SpeB), and NAD glycohydrolase (NADase), which are produced by Streptococcus pyogenes type T-25, with a food poisoning outbreak. The three virulence factors were analyzed by activity and amount of protein using supernatants at 2-30Â h of culture. All these virulence factors were confirmed by their activity. Streptolysin O (SLO), SpeB, and NADase were immunochemically confirmed at protein level by Western blot analysis. Two hemolytic forms (70 and 60Â kDa) of SLO were identified. SpeB was detected as a 44-kDa precursor form and a 30-kDa mature form. NADase was 50Â kDa. SLO protein peaked at 8Â h of culture, which corresponded with the hemolytic activity peak. Conversion from precursor to SpeB protein peaked at 14Â h of culture. The conversion peak corresponded to the activity expression time. Also, mature SpeB protein peaked at 24Â h of culture and corresponded to SpeB activity peak. Electrophoretic analysis clarified the relationship between SLO protein and SpeB protein, although amounts of SLO and SpeB have been reported to be inversely proportional to activity. NADase protein peaked at 12Â h of culture, but protein level did not correspond to the peak. Because the NADase protein peak was closer to SpeB activity than SLO protein, our results suggested NADase protein was degraded at 12Â h of culture. The time course production of these virulence factors is discussed.
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Authors
Takeshi Kanno, Kazuko Sakaguchi, Jun Suzuki,