Characterization of 2 linear peptides without disulfide bridges from the venom of the spider Lycosa poonaensis (Lycosidae)

Determining the pharmacological potential and biological role of linear pseudoscorpion toxins via functional profiling

Arthropod venoms contain bioactive molecules attractive for biomedical applications. However, few of these have been isolated, and only a tiny number has been characterized. Pseudoscorpions are small arachnids whose venom has been largely overlooked. Here, we present the first structural and functional assessment of the checacin toxin family, discovered in the venom of the house pseudoscorpion (Chelifer cancroides). We combined in silico and in vitro analyses to establish their bioactivity profile against microbes and various cell lines. This revealed inhibitory effects against bacteria and fungi. We observed cytotoxicity against specific cell types and effects involving second messengers. Our work provides insight into the biomedical potential and evolution of pseudoscorpion venoms. We propose that plesiotypic checacins evolved to defend the venom gland against infection, whereas apotypic descendants evolved additional functions. Our work highlights the importance of considering small and neglected species in biodiscovery programs.

Characterization of an antimicrobial peptide family from the venom gland of Heteropoda venatoria

Spider venom boasts extensive peptide diversity, constituting a natural biochemical arsenal for defense and predation. The new family HvAMPs, including 9 homologous members, were identified from the unnormalized cDNA library of Heteropoda venatoria venom gland by Sanger sequencing. The putative mature peptide is composed of 22 aliphatic amino acid residues. The mature peptides of HvAMP1 and HvAMP5, with 3 different amino acids, were synthesized and both were shown to adopt an amphipathic α-helical structure and amphipathicity in SDS buffer by CD spectroscopy. In comparison to HvAMP1, HvAMP5 exhibits higher antibacterial activity, particularly against Gram-positive bacteria, coupled with reduced hemolytic activity and cytotoxicity. Results from SYTO 9/PI staining indicate that HvAMP5 acts by disrupting bacterial cell membranes. Analysis of the relationships between structures and functions suggests that HvAMP5 enhances antibacterial activity and reduces mammalian cell toxicity by increasing positive charge and proline substitution. The three residues variation can augment the electrostatic attraction of antibacterial peptides to the bacterial phospholipid bilayer. The present study suggests that the HvAMPs may exert lytic action against cells of different origins to increase cellular and tissue barrier permeability to facilitate spider's defense or predation. Moreover, HvAMP5 holds promise as a novel antibacterial agent for treating Gram-positive bacterial infections. Simultaneously, the numerous diverse amino acid residue substitutions within the HvAMP family offer a template for future study.

Spider-Venom Peptides: Structure, Bioactivity, Strategy, and Research Applications

Spiders (Araneae), having thrived for over 300 million years, exhibit remarkable diversity, with 47,000 described species and an estimated 150,000 species in existence. Evolving with intricate venom, spiders are nature's skilled predators. While only a small fraction of spiders pose a threat to humans, their venoms contain complex compounds, holding promise as drug leads. Spider venoms primarily serve to immobilize prey, achieved through neurotoxins targeting ion channels. Peptides constitute a major part of these venoms, displaying diverse pharmacological activities, and making them appealing for drug development. Moreover, spider-venom peptides have emerged as valuable tools for exploring human disease mechanisms. This review focuses on the roles of spider-venom peptides in spider survival strategies and their dual significance as pharmaceutical research tools. By integrating recent discoveries, it provides a comprehensive overview of these peptides, their targets, bioactivities, and their relevance in spider survival and medical research.

Functional Profiling of the A-Family of Venom Peptides from the Wolf Spider Lycosa shansia

The venoms of spiders from the RTA (retro-lateral tibia apophysis) clade contain diverse short linear peptides (SLPs) that offer a rich source of therapeutic candidates. Many of these peptides have insecticidal, antimicrobial and/or cytolytic activities, but their biological functions are unclear. Here, we explore the bioactivity of all known members of the A-family of SLPs previously identified in the venom of the Chinese wolf spider (Lycosa shansia). Our broad approach included an in silico analysis of physicochemical properties and bioactivity profiling for cytotoxic, antiviral, insecticidal and antibacterial activities. We found that most members of the A-family can form α-helices and resemble the antibacterial peptides found in frog poison. The peptides we tested showed no cytotoxic, antiviral or insecticidal activities but were able to reduce the growth of bacteria, including clinically relevant strains of Staphylococcus epidermidis and Listeria monocytogenes. The absence of insecticidal activity may suggest that these peptides have no role in prey capture, but their antibacterial activity may help to defend the venom gland against infection.

Molecular Diversity of Linear Peptides Revealed by Transcriptomic Analysis of the Venom Gland of the Spider Lycosa poonaensis

Spider venom is a complex mixture of bioactive components. Previously, we identified two linear peptides in Lycosa poonaensis venom using mass spectrometric analysis and predicted the presence of more linear peptides therein. In this study, a transcriptomic analysis of the L. poonaensis venom gland was conducted to identify other undetermined linear peptides in the venom. The results identified 87 contigs encoding peptides and proteins in the venom that were similar to those in other spider venoms. The number of contigs identified as neurotoxins was the highest, and 15 contigs encoding 17 linear peptide sequences were identified. Seven peptides that were representative of each family were chemically synthesized, and their biological activities were evaluated. All peptides showed significant antibacterial activity against Gram-positive and Gram-negative bacteria, although their selectivity for bacterial species differed. All peptides also exhibited paralytic activity against crickets, but none showed hemolytic activity. The secondary structure analysis based on the circular dichroism spectroscopy showed that all these peptides adopt an amphiphilic α-helical structure. Their activities appear to depend on the net charge, the arrangement of basic and acidic residues, and the hydrophobicity of the peptides.