Table 1.
Sequence of synthetic lipopeptide.
Fig 1.
Synthesis of surfactin analogues.
(A) Chemical structures of surfactin and novel synthetic lipopeptides. The peptides are indicated using IUPAC single-character symbols, and the superscripts indicate amino acid chirality. (B) Mass spectra of synthetic surfactant analogues.
Fig 2.
Anti-PEDV activities of lipopeptides.
(A) PEDV was incubated with series concentrations of SLPs for 10 minutes at 37 °C. After washing cells of unadsorbed virus, the remaining infectious particles was detected by plaque assay. (B) Anti-PEDV activity (% remaining PFU) plotted as a function of lipopeptide concentration. The results of three independent experiments are shown as means ± standard deviation. 100% represents plaque counts in the control (no lipopeptide) sample.
Fig 3.
Hemolytic activity of lipopeptides.
(A) The indicated concentration of SLPs were added to a 1% porcine RBC suspension in PBS, followed by incubation for 1 h at 37 °C and centrifugation. Pictures were taken after collecting a portion of the supernatant for quantification of hemolysis. (B) Hemolytic curve. Hemolysis (measured at OD540) is shown as a function of SLP concentration. 100% represents the OD obtained using 0.1% Triton X-100-treated red blood cells.
Table 2.
Biological activities of surfactin and its analogues.
Fig 4.
Critical micelle concentrations of the SLPs.
CMCs were determined for SDS, surfactin, and SLPs by surface tension. The intersection of the two linear regression lines corresponds to the CMC value, (shown by the dotted lines).
Table 3.
Critical micelle concentration values.
Fig 5.
Correlation of SLPs eigenvalues.
Scattergrams of (A) EC50-CMC, (B) CC50-CMC, and (C) CC50-EC50 for surfactin and SLPs. The dotted lines show the results of linear regression for each scattergram, along with R2 and p values. None of the correlations are significant.
Fig 6.
(A) Vero cells were treated with SLP5, surfactin, or DEPE at different time points before, during, and after infection. The presence of the reagent is indicated by arrows. The treatment group number is on the left of the figure. Samples were harvested at 12 hpi. (B) The PEDV nucleoprotein was detected by Western-blot, and (C) quantitated by band intensity relative to the internal control, GAPDH. (D) The PEDV genome was detected by qRT-PCR. The experiment was repeated three times, normalized against Group 1, and plotted as mean ± SD. *, p < 0.05; **, p < 0.01 in two-tail t-test, for each reagent, compared with Group 1.