Neglected Venomous Animals and Toxins: Underrated Biotechnological Tools in Drug Development

Chemical Synthesis and Insecticidal Activity Research Based on α-Conotoxins

The escalating resistance of agricultural pests to chemical insecticides necessitates the development of novel, efficient, and safe biological insecticides. Conus quercinus, a vermivorous cone snail, yields a crude venom rich in peptides for marine worm predation. This study screened six α-conotoxins with insecticidal potential from a previously constructed transcriptome database of C. quercinus, characterized by two disulfide bonds. These conotoxins were derived via solid-phase peptide synthesis (SPPS) and folded using two-step iodine oxidation for further insecticidal activity validation, such as CCK-8 assay and insect bioassay. The final results confirmed the insecticidal activities of the six α-conotoxins, with Qc1.15 and Qc1.18 exhibiting high insecticidal activity. In addition, structural analysis via homology modeling and functional insights from molecular docking offer a preliminary look into their potential insecticidal mechanisms. In summary, this study provides essential references and foundations for developing novel insecticides.

Recombinant Analogs of Sea Anemone Kunitz-Type Peptides Influence P2X7 Receptor Activity in Neuro-2a Cells

Purinergic P2X7 receptors (P2X7) have now been proven to play an important role and represent an important therapeutic target in many pathological conditions including neurodegeneration. Here, we investigated the impact of peptides on purinergic signaling in Neuro-2a cells through the P2X7 subtype in in vitro models. We have found that a number of recombinant peptides, analogs of sea anemone Kunitz-type peptides, are able to influence the action of high concentrations of ATP and thereby reduce the toxic effects of ATP. The influx of calcium, as well as the fluorescent dye YO-PRO-1, was significantly suppressed by the studied peptides. Immunofluorescence experiments confirmed that the peptides reduce the P2X7 expression level in neuronal Neuro-2a cells. Two selected active peptides, HCRG1 and HCGS1.10, were found to specifically interact with the extracellular domain of P2X7 and formed stable complexes with the receptor in surface plasmon resonance experiments. The molecular docking approach allowed us to establish the putative binding sites of the most active HCRG1 peptide on the extracellular domain of the P2X7 homotrimer and propose a mechanism for regulating its function. Thus, our work demonstrates the ability of the Kunitz-type peptides to prevent neuronal death by affecting signaling through the P2X7 receptor.

Unraveling and profiling Tityus bahiensis venom: Biochemical analyses of the major toxins

Among the scorpions found in Brazil, Tityus bahiensis is one of the species that causes most of the reported human accidents. In spite of this important constatation, the venom composition description is not available in the literature. Thus, this venom remains not properly studied, segregating this particular species into an abandoned, forgotten condition. In the present study, chromatographic separation (RP-HPLC-C18) and proteomic analyses were employed to unravel the diversity, complexity, and proportional distribution of the main peptides and proteins found in the scorpion venom. Moreover, sequence analyses and the presence of new isoforms and toxins are discussed based on a database comparison with other Tityus toxins. Our results show the presence of a wide diversity of potassium and sodium channel toxins and enzymes, such as metallopeptidases and hyaluronidases, as previously described for other species. However, the current work also describes for the first time, at the protein level, phospholipase, angiotensin-converting enzyme, cysteine-rich proteins, serine peptidase inhibitors peptides, and antimicrobial peptides. Finally, thorough data analyses allowed the description of the venom toxins distribution regarding their diversity and relative quantity. SIGNIFICANCE: The work presents the first Tityus bahiensis proteome. We have focused on describing the neurotoxin variability in terms of their isoforms/amino acid substitutions. Understanding the natural variations in the toxins' sequences is essential, once the affinity of these peptides to their respective receptors/ionic channels will vary depending on the specific peptide sequences. Moreover, the current study describes some proteins present in the venom, including enzymes being described for the first time in scorpion venoms, such as PLA2 and ACE. Moreover, we describe the individual relative quantity distribution for the different protein classes identified, as well as their variability in the T.bahiensis venom. Finally, this study also reports the development of a simple straightforward chromatographic method for scorpion venom fractionation.