Intraspecific diversity of scorpions venom and its implication in the pathophysiological effects

Abstract

ABSTRACT:The present study was conducted to explore the following hypotheses: (i) do scorpions (the Egyptian scorpion Scorpio maurus palmatus) from different geographical locations exhibit intraspecific diversity in their venom? (ii) if so, is the variation associated with ecological or genetic factors, geographical distance, and/or multiple interrelated factors? and (iii) do the different toxins produce different physiological and toxicological effects to prey? To discover whether there are qualitative differences in the morphological characters and venom composition of S. m. palmatus, individuals were collected from four geographically isolated localities in Egypt. Three of these locations were from mutually isolated pockets in the arid area of Southern Sinai (Wadi Sahab, El-Agramia and Rahaba plains). The fourth population was sampled from the semi-arid environment of Western Mediterranean Costal Desert (WMCD). The investigation was divided into three main parts. In the first part, we showed that there are morphological differences between geographically separated populations of S. m. palmatus and that some aspects of their ecology are distinct. The second part examined intraspecific diversity of scorpion venom (pooled and individual) using SDS-PAGE technique. We also estimated the genetic distance between the four scorpion populations using some molecular techniques (Random Amplified Polymorphic DNA -RAPD, DNA sequence of RAPD markers, and Restriction Fragment Length Polymorphism -RFLP). Finally, we examined the neurotoxic and cytotoxic effects of venom drawn from the four populations on adult cockroach Periplanita americana. Most of the morphometric measurements (total body length, pedipalp length, chela width, number of setae on legs and number of pectinal teeth) revealed highly significant differences among the four populations. Pearson correlation matrix showed an interaction between morphometric measurements and some environmental factors (altitude, soil nature, and climate). This is the first time that a widely distributed scorpion species has been shown to produce a non-uniform cocktail of venom which varies with geographic location. Electrophoresis and a densitometric gel scan showed that pooled venom of WMCD origin contains several protein bands which are absent in Sinai-sourced

The Cuban scorpion Rhopalurus junceus (Scorpiones, Buthidae): component variations in venom samples collected in different geographical areas

“…Taken together, all these results suggest that the scorpions in these five different areas of Cuba are either from the same species or subspecies of R. junceus , with the variations already indicated (differences in sex ratio used for milking), or intraspecific variations present in venom of scorpions from other regions [12-15]. …”

“…Intraspecific venom variation has been previously studied in scorpions [12-15], and extensively in snakes [16,17]. As well as being of interest in the study of the ecology and evolution of venomous animals, this phenomenon is relevant to therapy for scorpion stings and snakebites.…”

Biochemical and Electrophysiological Characterization of Two Sea Anemone Type 1 Potassium Toxins from a Geographically Distant Population of Bunodosoma caissarum

“…Furthermore, investigation of intraspecific venom variation of four different populations of Scorpio maurus palmatus from geographically distant locations revealed highly significant differences among all populations and within each population studied. This may be due to geographic differential distribution of prey species, as well as their relative abundance in the environment [49,56]. Also, it has been demonstrated that ontogenetic variation of viperid snakes (Chordata, Reptilia, Viperidae) venoms could be related to differences between the feeding habits of juvenile and adult snakes, suggesting that variation in venom composition may reflect natural selection for greater efficiency in killing and digesting different prey types within the same location or in different locations [57,58,59].…”