Venom composition in the medical important scorpion Leiurus abdullahbayrami from The Middle East

 

The 23 species in the genus Leiurus Ehrenberg, 1828 (Buthidae) have the most potent venom of all scorpions and posing a medical threat to humans in their area of distribution. Knowledge of the venom composition and potency of the different species is important for correct treatment and the use of antivenom.

Adolfo Borges and Bruno Lomonte have recently published a study of the venom composition of Leiurus abdullahbayrami Yagmur, Koc & Kunt, 2009, distributed in Turkey, Syria, and Lebanon. This species have been involved in serious envenomations and this study confirms the potency of its venom. 

The study also found that the venom composition in Leiurus abdullahbayrami and other species vary and more research on this potential interspecific variation is necessary to decide whether a species-specific antivenom is necessary for sting cases involving this species.

Abstract:
The scorpion Leiurus abdullahbayrami has been associated with severe/lethal envenomings throughout the Levant region of the Middle East, encompassing Turkey, Syria, and Lebanon, and only scarce information is available on its venom composition, activity, and antigenicity. We report on the composition of L. abdullahbayrami venom collected from Lebanese specimens using nESI-MS/MS, MALDI-TOF MS, SDS-PAGE and RP-HPLC. Venom lethality, through LD50 determination in mice (intraperitoneal), was also assessed (0.75 (0.16–1.09) mg/kg), confirming L.abdullahbayrami venom vertebrate toxicity. Fifty-four peaks were detected using RP-HPLC, half of which eluted in the gradient region between 20 and 40% acetonitrile. In reducing SDS-PAGE, most predominant components were <10 kDa, with minor components at higher molecular masses of 24.4, 43.1, and 48.9 kDa. Venom mass fingerprint by MALDI-TOF detected 21 components within the 1000–12,000 m/z range. Whole venom ‘shotgun’ bottom-up nLC-MS/MS approach, combined with in-gel tryptic digestion of SDS-PAGE bands, identified at least 113 different components belonging to 15 venom families and uncharacterized proteins, with ion channel-active components (K+ channel toxins (28); Na+ channel toxins (42); Cl􀀀 channel toxins (4); Ca+ toxins (2)) being predominant. A single match for a L. adbullahbayrami NaTx was found in the UniProt database with other congeneric species, toxin h3.1 from Leiurus hebraeus, suggesting this might be an indication of venom divergence within Leiurus, eventhough this warrants further investigation involving venom proteomics and transcriptomics of relevant species. Considering such potential interspecific venom variation, future work should address whether preparation of a specific anti-L. abdullahbayrami antivenom is justified.

Reference:
Borges A, Lomonte B. Venomics of Leiurus abdullahbayrami, the most lethal scorpion in the Levant region of the Middle East. Toxicon. 2024;237:107548. [Subscription required for full text]

Thanks to Luis A. Roque for informing me about this article!