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Figure 1 | BMC Biotechnology

Figure 1

From: Mucosal delivery of anti-inflammatory IL-1Ra by sporulating recombinant bacteria

Figure 1

Release of IL-1Ra from recombinant B. subtilis. A. Schematic representation of the life cycle of B. subtilis showing the mechanism of recombinant IL-1Ra release upon sporulation (autolysis with spore formation, as in Spo+ strain), and destructive autolysis (with cell lysis without spore formation, as in Spo- strain). B. Presence of recombinant IL-1Ra in sporulation supernatant of pSM539 Spo+ strain, assessed by ELISA (mean ± SEM). IL-1Ra amount in sporulation supernatants was also quantitatively evaluated by laser scanning densitometry. The amount of IL-1Ra released in vitro by 0.5–0.7 × 109 bacteria (0.25 g wet weight) 3 h after the sporulation signal was 1.152 mg in 9.6 mg total released proteins (i.e., 12% of the total protein in the sporulation supernatant). Overlapping results were obtained with Spo- pSM539 cells (data not shown). C. SDS-PAGE analysis of wild-type B. subtilis (lane 1) and of recombinant B. subtilis pSM539 Spo- strain expressing IL-1Ra (lane 2). Asterisk indicates the migration position of human mature IL-1Ra. The protein identity was confirmed in Western blotting. Identical results were obtained with the Spo+ strain (data not shown).

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