Fig 1.
Medically important Indian snakes and their venom profiles.
(A) and (B) are indicative of sampling locations and photographs of neglected snakes and their ‘big four’ counterparts, respectively. The map of India shown in panel (A) was prepared using QGIS 3.8 [20]. (C) venom samples, normalized for protein content (12–15 μg), were loaded onto 12.5% SDS-PAGE. Lane numbers indicate corresponding species (M: pre-stained protein ladder).
Fig 2.
Comparative venom profiles of the medically important Indian snakes.
Venom compositions of Naja (A), Echis (B) and Bungarus (C) species are depicted as pie charts, and the relative composition of toxins are indicated in percentiles. A unique colour key for individual toxins is provided.
Fig 3.
Distinct biochemical profiles of the neglected snakes and their ‘big four’ counterparts.
(A) Relative enzymatic activity of PLA2; (B) Relative LAAO activity (absorbance units); (C) Specific hyaluronidase activity (TRU/mg/min); (D) Relative protease activity (%); (E) and (F) dose-dependent effect on activated partial thromboplastin time (aPTT) and prothrombin time (PT), respectively, where time (sec) is plotted against venom concentration (μg). All assays, with the exception of (E) and (F), were performed in triplicates and the standard deviation is indicated by error bars. A colour code is provided, which corresponds to the respective species of snake.
Fig 4.
Binding efficacy of commercial polyvalent antivenoms against the venoms of medically important Indian snakes.
Binding efficacy determined using an end-point ELISA is depicted here. Optical density at 405 nm is plotted against various dilutions of antivenoms. The values are provided as mean absorbance of triplicates, and error bars represent standard deviation. The dotted lines represent antivenom titres, which were determined using purified IgG from unimmunized horses as negative control. Alphabets next to the dotted lines indicate the titre of the respective antivenom (P: Premium Serums & Vaccines Pvt. Ltd.; V: VINS Bioproducts Ltd.; B: Bharat Serums and Vaccines Ltd; and H: Haffkine Institute).
Fig 5.
Identification of untargeted toxins via western blotting.
This figure depicts the results of western blotting experiments. Following the electrophoretic separation of snake venoms (25 μg) on a 4–20% gradient SDS-PAGE (A), bands were electroblotted onto nitrocellulose membranes, and incubated with 1:200 dilutions of various antivenoms: (B) Naïve IgG; (C) Premium Serums & Vaccines Pvt. Ltd.; (D) VINS Bioproducts Ltd.; (E) Bharat Serums; and (F) Haffkine Institute.
Fig 6.
Toxicity profiles of snake venoms and neutralising potencies of commercial antivenoms.
(A) and (B) depict the median lethal doses of various medically important snakes and the neutralising potency of Premium Serums antivenom, respectively. Vertical solid and dotted lines in panel (B) indicate marketed neutralising potencies of antivenoms against N. naja (0.60 mg/mL), and B. caeruleus and E. carinatus (0.45 mg/mL), respectively.