Individual Variability in Bothrops atrox Snakes Collected from Different Habitats in the Brazilian Amazon: New Findings on Venom Composition and Functionality

Abstract

Differences in snake venom composition occur across all taxonomic levels and it has been argued that this variation represents an adaptation that has evolved to facilitate the capture and digestion of prey and evasion of predators. Bothrops atrox is a terrestrial pitviper that is distributed across the Amazon region, where it occupies different habitats. Using statistical analyses and functional assays that incorporate individual variation, we analyzed the individual venom variability in B. atrox snakes from four different habitats (forest, pasture, degraded area, and floodplain) in and around the Amazon River in Brazil. We observed venom differentiation between spatially distinct B. atrox individuals from the different habitats, with venom variation due to both common (high abundance) and rare (low abundance) proteins. Moreover, differences in the composition of the venoms resulted in individual variability in functionality and heterogeneity in the lethality to mammals and birds, particularly among the floodplain snakes. Taken together, the data obtained from individual venoms of B. atrox snakes, captured in different habitats from the Brazilian Amazon, support the hypothesis that the differential distribution of protein isoforms results in functional distinctiveness and the ability of snakes with different venoms to have variable toxic effects on different prey.

Clinical and Evolutionary Implications of Dynamic Coagulotoxicity Divergences in Bothrops (Lancehead Pit Viper) Venoms

“…Although studies on specific coagulation factor activation were not performed, the strong procoagulant toxicity is likely achieved through coagulation factor activation (e.g., prothrombin and FX activation) [ 36 , 38 , 39 , 40 , 41 , 42 , 43 ]. Consistent with previous studies using more limited datasets [ 15 , 16 , 17 , 43 ] interspecific and intraspecific variations were noted.…”

“…Today, Bothrops species are found across many habitats and diverse niches [ 11 , 12 , 13 , 14 ], allowing for both inter- and intra-specific venom variation. In fact, Bothrops are known to exhibit geographical venom variation, with the same species having different venom action based on their geography/habitat [ 15 , 16 , 17 ]. For example, Segura et al [ 17 ] found venom variation between Mexican and Costa Rican B. asper venom samples, with Mexican B. asper venom having higher lethality to mice and higher in vivo defibrinogenating activity, but lower in vivo haemorrhagic activity and lower in vitro coagulant activity compared to Costa Rican B. asper venom samples.…”

“…For example, Segura et al [ 17 ] found venom variation between Mexican and Costa Rican B. asper venom samples, with Mexican B. asper venom having higher lethality to mice and higher in vivo defibrinogenating activity, but lower in vivo haemorrhagic activity and lower in vitro coagulant activity compared to Costa Rican B. asper venom samples. Sousa et al [ 16 ] investigated, at a finer scale, B. atrox in a section of the Brazilian Amazon (western region of the state of Pará), and found differences in venom composition and in the function between venom samples collected from different habitats. Consequently, due to the large and intricate landmass of Latin America and the many habitat types one species may inhabit across its range, more studies on intra-specific, geography-based venom variation are needed in this genus.…”

Biodiversity and public health interface

“…A new mathematical model to explain the dynamics of zoonotic transmission of malaria in these areas was proposed (Medeiros- Sousa et al 2021) Simulations performed with the model indicate that the dynamics of zoonotic transmission of malaria in the Atlantic Forest can vary depending on the abundance and acrodendrophily of the vector mosquito. The findings indicated that (i) an increase in the abundance of the vector in relation to the total number of blood-seeking mosquitoes leads to an asymptotic increase in the proportion of infected individuals at steady state and R0, (ii) the proportion of infected humans at steady state increases with increasing displacement of the vector mosquito between the forest strata, (ii) in most scenarios, Plasmodium transmission would not be sustained between mosquitoes and humans alone, implying that nonhuman primates play an important role in maintaining the transmission cycle.…”

Celebrating 120 Years of Butantan Institute Contributions for Toxinology

“…We selected 19 original articles and 4 reviews approaching several points of Toxinology. The venom of snakes was approached in different aspects as the structural and functional variability in the composition of venoms from individual snakes [1], the mechanisms of action of whole venoms [2,3], the mechanisms of action of individual components as crotoxin [4], phospholipases A2 [5], metalloproteinases [6][7][8], and the oral immunity induced by whole venoms and their components [9]. Venoms from other animals are also reported; the venoms of centipedes [10], scorpions [11,12], fishes [13,14], and caterpillars [15], including microbial toxins [16].…”