Differences between Two Groups of Burmese Vipers (Viperidae: Azemiops) in the Proteomic Profiles, Immunoreactivity and Biochemical Functions of Their Venoms

Two recently revised Azemiops snakes with apparent differences in their external appearances and skeletal morphologies but unclear genetic boundaries have been proposed. Some researchers have refrained from using the newly proposed taxonomy because these two "species" might be two clades corresponding to different geographical populations of Azemiops feae. To improve the understanding of the kinship of these two Burmese viper groups, more of their characteristics should be explored in depth. We performed a comparative analysis of the proteomic profiles and biochemical activities of snake venoms from these two groups (Sichuan A. feae and Zhejiang A. feae) and evaluated the immunorecognition capacity of commercial antivenoms toward them. Eight protein families were identified in venoms from these two groups, while phospholipase B was only detected in venom from Sichuan A. feae. These protein families displayed varying degrees of differences in relative abundance between venoms, and phospholipase A(2) (Sichuan A. feae: 57.15%; Zhejiang A. feae: 65.94%) was the predominated component. Gloydius brevicaudus antivenom exhibited the strongest capacity to immunologically recognize these two venoms, but this was mainly limited to components with high molecular masses, some of which differed between venoms. Additionally, Zhejiang A. feae venom was more toxic than Sichuan A. feae venom, and the venoms expressed remarkable differences in enzymatic activities, probably resulting from the variation in the relative abundance of specific protein families. Our findings unveil differences between the two Burmese viper groups in terms of proteomic profiles, immunoreactivity, and the biochemical functions of their venoms. This information will facilitate the management of snakebites caused by these snakes.