(A) 32 peptides isolated from the skin of H. bahuvistara were incubated with H1N1 PR8 influenza for 2 hr and virus growth was assessed by plaque assay. OVA control-treated virus was set as 100% virus growth. Peptides were used at 10 μM, except peptides 11, 26, 28, 29, 32, which were tested at lower concentrations due to hemolytic activity at 10 μM. Peptides highlighted in red significantly reduced viral titers in comparison to OVA control.

(B and C) Serially diluted frog peptides or OVA in PBS were incubated with human RBCs for 1 hr. Peptide toxicity was compared to lysis induced by 0.1% Triton X-100, which was set as 100% cell lysis, and PBS as 0% lysis.

Hopp and Woods, 1981 Hopp T.P.

Woods K.R. Prediction of protein antigenic determinants from amino acid sequences. (D) Sequence of urumin on the Hopp & Woods amino acid hydrophilicity scale ().

(E) Graded concentrations of urumin (0.6–320 μM) were incubated with PR8 for 2 hr and IC 50 was determined by peptide-induced virus growth inhibition as assessed by plaque assay.

(F) 10 μM urumin or OVA was incubated with PR8 for 5–60 min and kinetics of urumin activity was determined by virus growth inhibition as assessed by plaque assay.