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.

Androctonus mauretanicus (A. mauretanicus) and Buthus occitanus (B. occitanus) scorpions, which belong to the Buthidae family, are the most venomous scorpions in Morocco. For the first time, we investigated the effects of such scorpion venoms on serum electrolytes in subcutaneously injected rabbits. For this purpose, 3 groups of 6 albinos adult male rabbits (New Zealand) were used in this experiment. Two of the groups were given a single subcutaneous injection of either crude Am venom (5 μg/kg) or Bo venom (8 μg/kg) whereas the third group (control group) only received physiological saline solution (NaCl 0.9%). The blood samples were collected from injected rabbits via the marginal vein at time intervals of 30 min, 1 h, 2 h, 4 h, 6 h and 24 h after venom injection. The concentrations of electrolytes in the serum samples were measured. Our study indicates that scorpion envenomation in vivo, rabbit animal model, caused severe and persistent hypomagnesaemia and hypochloremia, which are accompanied of hypernatremia, hyperkalemia and hypercalcaemia. The intensity of electrolytes imbalance was clearly superior in the case of A. mauretanicus scorpion venom (although a lower quantity of venom was injected). This is coherent with the experimental data which indicate that A. mauretanicus venom is more toxic than B. occitanus venom.

A disintegrin and metalloproteinase (ADAM) family proteins are a major class of membrane-anchored multidomain proteinases that are responsible for the shedding of cell surface protein ectodomains, including amyloid precursor protein (APP). Human ADAM 9, 10, and 17 proteolyze APPs and produce non-amyloid-genic p3 peptides, instead of neurotoxic amyloid-β peptides (Aβs; Aβ40 and Aβ42), which form fibrils and accumulate in the brain of patients with Alzheimer’s disease (AD). The ADAM family is closely related to snake venom metalloproteinases (SVMPs), which are derived from ancestral ADAMs but act as soluble proteinases. To test the therapeutic potential of SVMPs, we purified SVMPs from Protobothrops flavoviridis venom using metal ion affinity and pooled into a cocktail. Thus, 9 out of 11 SVMPs in the P. flavoviridis genome were identified in the cocktail. SVMPs inhibited Aβ secretion when added to human cell culture medium without affecting APP proteolysis. SVMPs degraded synthetic Aβ40 and Aβ42 peptides at the same cleavage site (α-site of APP) as ADAM9, 10, and 17. SVMPs did not degrade Aβ fibrils but interfered with their formation, assessed using thioflavin-T. Thus, SVMPs have therapeutic potential for AD as an Aβ-degrading protease, and the finding adds to the discovery of bioactive peptides from venoms as novel therapeutics.

The emergence of coronavirus disease 2019 (COVID-19) posed a major challenge to healthcare systems worldwide, especially as mutations in the culprit Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) complicated the development of vaccines and antiviral drugs. Therefore, the search for natural products with broad anti-SARS-CoV-2 capabilities is an important option for the prevention and treatment of similar infectious diseases. Lectins, which are widely recognized as antiviral agents, could contribute to the development of anti-SARS-CoV-2 drugs. This study evaluated the binding affinity of six lectins (including the cyanobacterial lectin from Microcystis viridis NIES-102 (MVL), and Jacalin, a lectin from the breadfruit, Artocarpus altilis) to the receptor binding domain (RBD) of the spike protein on the original (wild) SARS-CoV-2 and three of its mutants: Alpha, Delta, and Omicron. MVL and Jacalin showed distinct binding affinity to the RBDs of the four SARS-CoV-2 strains. The remaining four lectins (DB1, ConA, PHA-M and CSL3) showed no such binding affinity. Although the glycan specificities of MVL and Jacalin were different, they showed the same affinity for the spike protein RBDs of the four SARS-CoV-2 strains, in the order of effectiveness Alpha > Delta > original > Omicron. The verification of glycan-specific inhibition revealed that both lectins bind to RBDs by glycan-specific recognition, but, in addition, MVL binds to RBDs through protein–protein interactions.

Background: Androctonus mauretanicus (Am ) is one of the most hazardous scorpions in Morocco and has a highly toxic venom responsible for severe cases of envenomation. However, few studies have focused on deciphering its proteic composition. Objectives: Herein, we aim to map out the complete proteome of the Am venom filtrate to highlight its complexity and the polymorphism of its toxic content. This, in turn, will lead to a deeper understanding of the toxins’ mechanism of action and will help uncover those with therapeutic potential. Methods: Top-down and bottom-up proteomic approaches were used complementarily to decipher the proteome of the Am venom. These approaches were carried out on nano-high liquid chromatography coupled to nano-electrospray tandem mass spectrometry (Nano-LC-ESI-MS/MS). Results: Am venom encloses a complex mixture of 269 different compounds with molecular weights ranging from 1618.74 to 14 214.84 Da. The most abundant ones showed masses from 6185.92 to 7899.53 Da (53.89%) followed by those ranging from 2079.25 to 5969.63 Da (37.81%). Interestingly, the combination of the results of both approaches allowed the screening of a total of 112 peptides. The highest percentage was represented by neuropeptides (87%), including NaTxs, KTxs, ClTxs, venom proteins, venom neuropeptides, and myotropic neuropeptides. Moreover, other peptides were identified, such as antimicrobial peptides, amphipathic peptides, cysteine-rich venom peptides, enzymes, kunitz-type inhibitors and orphan peptides. Conclusion: The Am venom appears to contain a great number of diverse peptides, some of which could prospectively be exploited for their pharmaceutical potential.

γ-Secretase is a protease complex embedded in the cell membrane, consisting of the catalytic presenilin subunits (PS1 or PS2) and three additional co-factors: nicastrin, Aph-1, and Pen2. It cleaves the transmembrane domains of type-I transmembrane proteins, such as the amyloid precursor protein (APP) and Notch. The cleavage of APP generates the amyloid β peptides (Aβ), which accumulate in patients with Alzheimer's disease. Despite significant research, the exact mechanism of this unique proteolysis, which occurs within the lipid bilayers, is still not fully understood. To study the enzymatic properties of γ-secretase, we have established a yeast reporter system using artificial γ-secretase substrates containing APP or Notch fragments fused to the transcriptional activator Gal4. The γ-secretase activity was evaluated by transcriptional activation of reporter genes upon Gal4 release from the membrane-bound substrates, as assessed by the growth of yeast or β-galactosidase activity. Furthermore, we have developed an in vitro assay to identify the different forms of Aβ produced from yeast microsomes. These yeast models provide a platform to screen mutations, genes, and compounds that affect γ-secretase function. By studying the loss of function properties of PS1 familial Alzheimer's disease (FAD) mutants, it is possible to screen for FAD suppressor mutations and γ-secretase modulators (GSMs), in addition to γ-secretase inhibitors (GSIs). In this report, we describe the genetic and biochemical methods used to study γ-secretase activity in the yeast system with the essential steps of the protocol for the video.