Fig 1.
Appearance and distribution of the Arabian saw-scaled viper (Echis coloratus).
(A) Full-body photograph and (B) close-up of adult E. coloratus. (C) Geographic distribution of the species, based on data from the WHO Snakebite Information and Data Platform [11]. The map’s base layer was sourced from Natural Earth (https://www.naturalearthdata.com/downloads/50m-raster-data), which is in the public domain (http://www.naturalearthdata.com/about/terms-of-use). Photo credits: Thor Håkonsen.
Fig 2.
Characterisation of E. coloratus venom.
(A) RP-HPLC profile at 214 nm (black) and 280 nm (red), (B) one-dimensional SDS-PAGE profiles, and (C) relative abundances of the venom components based on NSAFs. In the SDS-PAGE profiles, venom toxin families were tentatively assigned based on the molecular masses estimated from SDS-PAGE analysis of reduced samples reported by Casewell et al. [54]. Abbreviations: M, marker; R, reduced; NR, non-reduced. Toxin family key: 5N, 5′-nucleotidase; CTL, C-type lectin and C-type lectin-related protein; CRISP, cysteine-rich secretory protein; DI, disintegrin; PDE, phosphodiesterase; PLA2, phospholipase A2; PLB, phospholipase B; QC, glutaminyl-peptide cyclotransferase; LAAO, L-amino-acid oxidase; SVMP, snake venom metalloproteinase; SVMPi/NP, snake venom metalloproteinase inhibitors/natriuretic peptides; SVSP, snake venom serine protease; VEGF, venom endothelial growth factor; VNGF, venom nerve growth factor.
Fig 3.
Protease and PLA2 activity of E. coloratus venom.
The graphs show the results at the final time point, the kinetic profile, and the normalized kinetic profile for protease activity (panels A, B, C) and PLA2 activity (panels D, E, F). Panels B and E show the optical density measured at 600 nm and expressed in Relative Fluorescence Units (RFU). The error bars represent standard deviation. For the protease activity assay, TPCK trypsin was applied as positive control, and TBS as negative control. For the PLA2 activity assay, bee venom PLA2 diluted in 1 × Reaction Buffer to a working solution of 10 U/ml PLA2 was applied as positive control, and 1 × Reaction Buffer as negative control.
Fig 4.
Biological activities of E. coloratus venom on different haematological targets.
The values presented in each graph refer to the normalised mean values of three measurements per concentration. The error bars represent standard deviation. The positive controls used were Thrombin Enzyme Standard for the thrombin-like activity assay, FXa Enzyme Standard for the FXa-like activity assay, Plasmin Enzyme Standard for the plasmin-like activity assay, and Triton X-100 for the haemolysis assay. For all assays, ddH2O was used as the negative control.
Fig 5.
Cytotoxicity of E. coloratus venom.
The graph shows the viability of the mammalian cell lines MDCK II and Calu-3 following treatment with the analysed venom. The error bars represent standard deviation.