INTRASPECIFIC VARIATION IN SCORPION LEIURUS QUINQUESTRIATUS VENOM COLLECTED FROM EGYPT (SINAI AND ASWAN DESERTS)

Leiurus quinquestriatus is a single species genus scorpion of Saharan origin, which has penetrated the Mediterranean region. The Sinai Isthmus is believed to be the region in which the subspecies L.q. quinquestriatus gives way to L.q. hebraeus. To test whether there are qualitative differences in the venom from Leiurus quinquestriatus inhabiting two different geographic regions, venom was obtained from scorpions collected from Aswan in Southern Egypt and from the Southern region of Sinai Peninsula, Egypt. Electrophoresis and a densitometric gel scan showed that in the molecular weight range above that known to include toxins, venom of Aswan origin contained several protein bands that were absent from Sinai-sourced venom. In contrast Sinai venom appeared to have a larger proportion of protein in the molecular weight range known to include toxins. Such differences may reflect a response to local ecological conditions. Application of equal concentrations by weight of the two venoms to rat ileum showed no difference in the contraction produced by the lowest effective dose (0.2 μg ml-1) but at higher doses (0.5, 1.0 & 2.0 μg ml-1) venom from Aswan induced stronger and more sustained contractions with a different time course than did Sinai scorpion venom. Geographically related intra-specific variation in venom composition might be important in treating the pathophysiological effects of scorpion venom. This is the first time that differences in the venom components and their physiological effectiveness has been demonstrated for the scorpion L. quinquestriatus venom collected from two distinct areas in Egypt.