Biochemical characterization of the venom of Central American scorpion Didymocentrus krausi Francke, 1978 (Diplocentridae) and its toxic effects in vivo and in vitro

Proteins from shrews' venom glands play a role in gland functioning and venom production

Venom production has evolved independently many times in the animal kingdom, although it is rare among mammals. Venomous shrews produce venom in their submandibular salivary glands and use it for food acquisition. Only a few toxins have been identified in shrew venoms thus far, and their modes of action require investigation. The biological and molecular processes relating to venom production and gland functioning also remain unknown. To address this gap, we investigated protein content in extracts from venom glands of two shrew species, Neomys fodiens and Sorex araneus, and interpreted their biological functions. Applying a proteomic approach coupled with Gene Ontology enrichment analysis, we identified 313 and 187 putative proteins in venom glands of N. fodiens and S. araneus, respectively. A search of the UniProt database revealed that most of the proteins found in both shrew species were involved in metabolic processes and stress response, while GO enrichment analysis revealed more stress-related proteins in the glands of S. araneus. Molecules that regulate molecule synthesis, cell cycles, and cell divisions are necessary to enable venom regeneration and ensure its effectiveness in predation and food hoarding. The presence of proteins involved in stress response may be the result of shrews' high metabolic rate and the costs of venom replenishment. Some proteins are likely to promote toxin spreading during envenomation and, due to their proteolytic action, reinforce venom toxicity. Finally, finding numerous proteins involved in immune response suggests a potential role of shrew venom gland secretions in protection against pathogens. These findings open up new perspectives for studying biological functions of molecules from shrew venom glands and extend our knowledge on the functioning of eulipotyphlan venom systems. Because the majority of existing and putative venomous mammals use oral venom systems to inject venom into target species, the methods presented here provide a promising avenue for confirming or discovering new taxa of venomous mammals.

Unveiling the Protein Components of the Secretory-Venom Gland and Venom of the Scorpion Centruroides possanii (Buthidae) through Omic Technologies

Centruroides possanii is a recently discovered species of "striped scorpion" found in Mexico. Certain species of Centruroides are known to be toxic to mammals, leading to numerous cases of human intoxications in the country. Venom components are thought to possess therapeutic potential and/or biotechnological applications. Hence, obtaining and analyzing the secretory gland transcriptome and venom proteome of C. possanii is relevant, and that is what is described in this communication. Since this is a newly described species, first, its LD50 to mice was determined and estimated to be 659 ng/g mouse weight. Using RNA extracted from this species and preparing their corresponding cDNA fragments, a transcriptome analysis was obtained on a Genome Analyzer (Illumina) using the 76-base pair-end sequencing protocol. Via high-throughput sequencing, 19,158,736 reads were obtained and ensembled in 835,204 sequences. Of them, 28,399 transcripts were annotated with Pfam. A total of 244 complete transcripts were identified in the transcriptome of C. possanii. Of these, 109 sequences showed identity to toxins that act on ion channels, 47 enzymes, 17 protease inhibitors (PINs), 11 defense peptides (HDPs), and 60 in other components. In addition, a sample of the soluble venom obtained from this scorpion was analyzed using an Orbitrap Velos apparatus, which allowed for identification by liquid chromatography followed by mass spectrometry (LC-MS/MS) of 70 peptides and proteins: 23 toxins, 27 enzymes, 6 PINs, 3 HDPs, and 11 other components. Until now, this work has the highest number of scorpion venom components identified through omics technologies. The main novel findings described here were analyzed in comparison with the known data from the literature, and this process permitted some new insights in this field.

The remarkably enzyme-rich venom of the Big Bend Scorpion (Diplocentrus whitei)

Scorpion venoms have long been studied for their peptide discovery potential, with modern high-throughput venom-characterization techniques paving the way for the discovery of thousands of novel putative toxins. Research into these toxins has provided insight into the pathology and treatment of human diseases, even resulting in the development of one compound with Food and Drug Administration (FDA) approval. Although most of this research has focused on the toxins of scorpion species considered medically significant to humans, the venom of harmless scorpion species possess toxins that are homologous to those from medically significant species, indicating that harmless scorpion venoms may also serve as valuable sources of novel peptide variants. Furthermore, as harmless scorpions represent a vast majority of scorpion species diversity, and therefore venom toxin diversity, venoms from these species likely contain entirely new toxin classes. We sequenced the venom-gland transcriptome and venom proteome of two male Big Bend scorpions (Diplocentrus whitei), providing the first high-throughput venom characterization for a member of this genus. We identified a total of 82 toxins in the venom of D. whitei, 25 of which were identified in both the transcriptome and proteome, and 57 of which were only identified in the transcriptome. Furthermore, we identified a unique, enzyme-rich venom dominated by serine proteases and the first arylsulfatase B toxins identified in scorpions.

French Scorpionism (Mainland and Oversea Territories): Narrative Review of Scorpion Species, Scorpion Venom, and Envenoming Management

Sixty-seven scorpion species have been described in France and its territories, where they have been found to be heterogeneously distributed. Indeed, only one species can be found on Réunion Island, while 38 species exist in French Guiana. The number of stings is also heterogenous, with up to 90 stings per 100,000 inhabitants occurring annually. Scorpion species can frequently be determined through simple visual factors, including species of medical importance (i.e., Buthus, Centruroides and Tityus). Scorpion venom is composed of local enzymes and peptides with a cysteine-stabilized α/β motif (NaTxs, Ktxs, Calcines), which allow for venom diffusion and the prey's incapacitation, respectively. Harmful scorpion species are limited to Centruroides pococki in the French West Indies, which can induce severe envenoming, and the Tityus obscurus and Tityus silvestris in French Guiana, which can cause fatalities in children and can induce severe envenoming, respectively. Envenomation by one of these scorpions requires hospital monitoring as long as systemic symptoms persist. Typical management includes the use of a lidocaine patch, pain killers, and local antiseptic. In the case of heart failure, the use of dobutamine can improve survival, and pregnant women must consult an obstetrician because of the elevated risk of preterm birth or stillbirth. France does not have scorpion antivenom, as scorpion stings are generally not fatal.

Biochemical characterization and insecticidal activity of isolated peptides from the venom of the scorpion Centruroides tecomanus

The venom of scorpions is a mixture of components that constitute a source of bioactive molecules. The venom of the scorpion Centruroides tecomanus contains peptides toxic to insects, however, to date no toxin responsible for this activity has yet been isolated and fully characterized. This communication describes two new peptides Ct-IT1 and Ct-IT2 purified from this scorpion. Both peptides contain 63 amino acids with molecular weight 6857.85 for Ct-IT1 and 6987.77 Da for Ct-IT2. The soluble venom was separated using chromatographic techniques of molecular size exclusion, cationic exchange, and reverse phase chromatography, allowing the identification of at least 99 components of which in 53 the insecticidal activity was evaluated. The LD₅₀ determined for Ct-IT1 is 3.81 μg/100 mg of cricket weight, but low amounts of peptides (0.8 μg of peptide) already cause paralysis in crickets. The relative abundance of these two peptides in the venom is 2.1% for Ct-IT1 and 1% for Ct-IT2. The molecular masses and N-terminal sequences of both insecticidal toxins were determined by mass spectrometry and Edman degradation. The primary structure of both toxins was compared with other known peptides isolated from other scorpion venoms. The analysis of the sequence alignments revealed the position of a highly conserved amino acid residue, Gly39, exclusively present in anti-insect selective depressant β-toxins (DBTXs), which in Ct-IT1 and Ct-IT2 is at position Gly40. Similarly, a three-dimensional structure of this toxins was obtained by homology modeling and compared to the structure of known insect toxins of scorpions. An important similarity of the cavity formed by the trapping apparatus region of the depressant toxin LqhIT2, isolated from the scorpion Leiurus quinquestriatus hebraeus, was found in the toxins described here. These results indicate that Ct-IT1 and Ct-IT2 toxins have a high potential to be evaluated on pests that affect economically important crops to eventually consider them as a potential biological control method.

Proteomic Changes during the Dermal Toxicity Induced by Nemopilema nomurai Jellyfish Venom in HaCaT Human Keratinocyte

Jellyfish venom is well known for its local skin toxicities and various lethal accidents. The main symptoms of local jellyfish envenomation include skin lesions, burning, prickling, stinging pain, red, brown, or purplish tracks on the skin, itching, and swelling, leading to dermonecrosis and scar formation. However, the molecular mechanism behind the action of jellyfish venom on human skin cells is rarely understood. In the present study, we have treated the human HaCaT keratinocyte with Nemopilema nomurai jellyfish venom (NnV) to study detailed mechanisms of actions behind the skin symptoms after jellyfish envenomation. Using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF/MS), cellular changes at proteome level were examined. The treatment of NnV resulted in the decrease of HaCaT cell viability in a concentration-dependent manner. Using NnV (at IC₅₀), the proteome level alterations were determined at 12 h and 24 h after the venom treatment. Briefly, 70 protein spots with significant quantitative changes were picked from the gels for MALDI-TOF/MS. In total, 44 differentially abundant proteins were successfully identified, among which 19 proteins were increased, whereas 25 proteins were decreased in the abundance levels comparing with their respective control spots. DAPs involved in cell survival and development (e.g., Plasminogen, Vinculin, EMILIN-1, Basonuclin2, Focal adhesion kinase 1, FAM83B, Peroxisome proliferator-activated receptor-gamma co-activator 1-alpha) decreased their expression, whereas stress or immune response-related proteins (e.g., Toll-like receptor 4, Aminopeptidase N, MKL/Myocardin-like protein 1, hypoxia up-regulated protein 1, Heat shock protein 105 kDa, Ephrin type-A receptor 1, with some protease (or peptidase) enzymes) were up-regulated. In conclusion, the present findings may exhibit some possible key players during skin damage and suggest therapeutic strategies for preventing jellyfish envenomation.

Antibacterial activity of a scorpion-derived peptide and its derivatives in vitro and in vivo

Antimicrobial peptides have recently become extremely popular as a novel class of antimicrobial agents. AMP MK049518 (FLGLLGSVLGSVLPSIFK), identified from the crab-scorpion Didymocentrus krausi, only possesses significant antibacterial activity against Gram-positive bacteria. In this study, a derivative G2K-S3K was designed with an excellent antibacterial spectrum and significantly higher antibacterial activity compared to the natural peptide. G2K-S3K also demonstrated excellent serum- and thermal-stability and did not induce bacterial resistance. In the Staphylococcus aureus and Pseudomonas aeruginosa -induced skin infection in mice, G2K-S3K significantly decreased bacterial counts in the wound by topical application. Thus, G2K-S3K could be a potent topical anti-infective agent against the skin infection caused by S. aureus and P. aeruginosa.