Comparative analyses and implications for antivenom serotherapy of four Moroccan scorpion Buthus occitanus venoms: Subspecies tunetanus, paris, malhommei, and mardochei

Molecular diversity assessed by MALDI mass spectrometry of two scorpion species venom from two different locations in Morocco

Scorpion venom is a cocktail of molecules whose composition is remarkably plastic, controlled by several factors. The Moroccan scorpion fauna is characterized by its richness and high rate of endemism and the venom molecular variability of many species is not yet well characterized. The aim of the present study was to highlight the molecular variability of the venom composition of Androctonus amoreuxi and Buthacus stockmanni (endemic species), both belonging to the Buthidae family, collected from two Moroccan regions, Zagora and Tan-tan. Characterization of the molecular mass fingerprints (MFPs) of each specimen was performed by Matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) using a sandwich (Sand) and a dried-droplet (DD) sample preparation and dilutions. Considering these two methods, a total of 828 ion signals were detected, and Sand method produced more adducts (56%) than DD (44%). We observed interspecific variations in the venom composition between these two species showing they share 235 ion signals, while 226 and 367 are specific for these two species, respectively. Moreover, B. stockmanni specimens showed a clear difference in their MFPs between the two geographical areas studied, suggesting intraspecific variations. Moreover, specimens from each population also show an intraspecific variability. In addition, for the same individual, a variation in the venom composition was also recorded depending on the milking frequency. Our results confirmed the presence of characteristic components in each extracted venom sample. In conclusion, MFPs assessed by MALDI-MS represent a fast, non-supervised, sensitive, reliable and cost-efficient approach for taxonomic identification and molecular variability characterization. This study undoubtedly represents a step forward for understanding the scorpion venom plasticity, intra/inter variations, and their temporal and geographical variability.

Comparative Proteomic Analysis of the Venoms from the Most Dangerous Scorpions in Morocco: Androctonus mauritanicus and Buthus occitanus

Morocco is known to harbor two of the world's most dangerous scorpion species: the black Androctonus mauritanicus (Am) and the yellow Buthus occitanus (Bo), responsible for 83% and 14% of severe envenomation cases, respectively. Scorpion venom is a mixture of biological molecules of variable structures and activities, most of which are proteins of low molecular weights referred to as toxins. In addition to toxins, scorpion venoms also contain biogenic amines, polyamines, and enzymes. With the aim of investigating the composition of the Am and Bo venoms, we conducted an analysis of the venoms by mass spectrometry (ESI-MS) after separation by reversed-phase HPLC chromatography. Results from a total of 19 fractions obtained for the Am venom versus 22 fractions for the Bo venom allowed the identification of approximately 410 and 252 molecular masses, respectively. In both venoms, the most abundant toxins were found to range between 2-5 kDa and 6-8 kDa. This proteomic analysis not only allowed the drawing of an extensive mass fingerprint of the Androctonus mauritanicus and Buthus occitanus venoms but also provided a better insight into the nature of their toxins.

Epidemiological, toxicological and physiopathological characteristics of scorpion stings and their management in Morocco: A literature review

All around the world, scorpion envenomation represents a public health issue. In Morocco, it represents the first cause of poisoning. The aim of this review is to highlight the epidemiological, toxicological and physiopathological characteristics of scorpion stings and envenomation in Morocco as well as their management. According to the bibliography, the most areas affected by scorpion stings and envenomation are those in the center and south of Morocco. Lethality rate is more important in children than adult. Age, admission class, season, serum venom concentration, and the time elapsed between the scorpion sting and medical intervention are risk factors for a poor prognosis. Until now, we have only known the LD50 of 14 scorpion species from three genera: Androctonus, Buthus and Hottentota, and only 6 species, out of 61 moroccan scorpions, have been assessed for their venom toxicity on mice organs. The venom of harmful moroccan scorpions induces several histopathological changes in the myocardium, brain, liver, pulmonary alveoli, and kidneys in rats, as well as severe consequences in the lungs with intra-alveolar hemorrhage. There was also a significant increase in serum enzyme levels of aspartate transaminase (AST), alanine transaminase (ALT), creatine phosphokinase (CPK), and lactate dehydrogenase (LDH), as well as high levels of plasma albumin, creatine and glucose. In the absence of a specific treatment, the management of scorpion envenomation is based only on symptomatic therapy. We noted a widely use of traditional remedies. Despite the magnitude of the scorpion problem in Morocco, it remains understudied and continues to claim lives, particularly given the lack of an efficient etiological cure.

Mass spectrometry-based top-down and bottom-up approaches for proteomic analysis of the Moroccan Buthus occitanus scorpion venom

Buthus occitanus (B. occitanus) is one of the most dangerous scorpions in the world. Despite the involvement of B. occitanus scorpion in severe cases of envenomation in Morocco, no study has focused yet on the proteomic composition of the Moroccan B. occitanus scorpion venom. Mass spectrometry‐based proteomic techniques are commonly used in the study of scorpion venoms. The implementation of top‐down and bottom‐up approaches for proteomic analyses facilitates screening by allowing a global view of the structural aspects of such complex matrices. Here, we provide a partial overview of the venom of B. occitanus scorpion, in order to explore the diversity of its toxins and hereafter understand their effects. To this end, a combination of top‐down and bottom‐up approaches was applied using nano‐high liquid chromatography coupled to nano‐electrospray tandem mass spectrometry (nano‐LC‐ESI MS/MS). The LC‐MS results showed that B. occitanus venom contains around 200 molecular masses ranging from 1868 to 16 720 Da, the most representative of which are those between 5000 and 8000 Da. Interestingly, combined top‐down and bottom‐up LC‐MS/MS results allowed the identification of several toxins, which were mainly those acting on ion channels, including those targeting sodium (NaScTxs), potassium (KScTxs), chloride (ClScTxs), and calcium channels (CaScTx), as well as antimicrobial peptides (AMPs), amphipathic peptides, myotropic neuropeptides, and hypothetical secreted proteins. This study reveals the molecular diversity of B. occitanus scorpion venom and identifies components that may have useful pharmacological activities.