Identification of a Peptide Produced by Bifidobacterium longum CECT 7210 with Antirotaviral Activity

Chenoll, Empar; Casinos, Beatriz; Bataller, Esther; Buesa, Javier; Ramón, Daniel; Genovés, Salvador; Fábrega, Joan; Rivero Urgell, Montserrat; Moreno Muñoz, José A.

In order to study, the nature of the substance of interest, the freeze-dried samples were treated with lipase and proteases (proteinase K and pepsin). To study the effect of lipase, a freeze-dried sample (from 25 mL supernatant) was re-suspended in 2.4 mL phosphate buffer solution (50 mM, pH 6.9), then 0.1 mL lipase from porcine pancreas was added (50 mg/mL; Sigma-Aldrich). The mixture was incubated at 37 • C for 2 h, and the reaction was inactivated taking the solution to pH 4.5. Regarding pepsin, a freeze-dried sample (from 25 mL supernatant) was re-suspended in 1.25 mL of McIlvaine buffer 50 mM pH 4.0, to which 0.109 mL of a pepsin solution was added (50 mg/mL; Sigma-Aldrich, St. Louis, MO, USA). This mixture was incubated at 37 • C for 2 h, and the reaction was inactivated taking the solution to pH 6.5 in a final volume of 2.5 mL. In the case of proteinase K, freeze-dried sample (from 25 mL supernatant) was re-suspended in 2.4 mL of phosphate buffer 50 mM pH 6.5, to which 0.1 mL of a proteinase K solution was added (50 mg/mL; Sigma-Aldrich). This mixture was incubated at 37 • C for 2 h, and then proteinase K was inactivated by incubation at 100 • C for 15 min. Analysis of the inhibition of proliferation of rotavirus SA11 was performed in all processed supernatants.