do Nascimento, S. M. | bioRxiv Science

bioRxiv2022

TsTX-kappa beta (Ts8), a neurotoxin from the venom of the scorpion Tityus serrulatus: antimicrobial and hemolytic activity.

Increase of infections caused by microorganisms resistant to conventional antibiotics is a health problem in Brazil and worldwide. The search for new molecules capable of inhibiting the growth of pathogens is a challenge for researchers, who find in venoms a rich source of biomolecules, including antimicrobial peptides (AMPs). The Brazilian scorpion, Tityus serrulatus, is one of the species that cause serious accidents; its venom is rich in neurotoxins that have been well characterized, highlighting their activities on channels (especially sodium and potassium). In this study we identifified and characterized one AMPs in T. serrulatus venom. After milking, the venom was fractioned by high performance liquid chromatography and the fractions were tested by liquid growth inhibition assay, the minimum inhibitory concentration (MIC) against Escherichia coli, Micrococcus luteus, Candida albicans and Aspergillus niger. The fraction identified with antimicrobial activity was analyzed by electrophoresis and mass spectrometry and this AMP (with molecular mass 6.882 kDa) has a similar amino acid sequence to TsTX-{kappa} beta, a neurotoxin that acts on ion channels. The TsTX-{kappa} beta in this study was identified by de novo sequencing. This peptide showed activity against all microorganisms tested. At high concentrations, this peptide, showed hemolytic activity against human erythrocytes. This is a new function described for this peptide, the identification of antimicrobial activity in a neurotoxin already known. Key ContributionMultifunction: antimicrobial and hemolytic activity associated to TsTX-{kappa} beta, a neurotoxin that acts on potassium channels.

microbiology↗

bioRxiv2022

How a tarantula can help treat infections: Avicularia juruensis theraphotoxins that also act as antimicrobials.

Short abstractConsidering that there are still many species little-studied, this work aimed to analyze the venom of the spider Avicularia juruensis searching for antimicrobial peptides. Using reverse-phase high-performance liquid chromatography, microbial growth inhibition assay, transcriptomics, and proteomics approaches we identified three antimicrobial peptides: Avilin, Juruin_2, and Juruenine. All of them showed similarities with neurotoxins that act on ion channels and, probably, they have the ICK motif. The study of animal venoms is of great importance to carry out the characterization of unknown components and that may have a biotechnological application, in special venoms from spiders that are from less studied families. Spiders are the most successful group of venomous animals, comprising more than 50,350 species distributed in all terrestrial habitats. One strategy that facility their broad distribution is the production of elaborate venoms, which are composed of inorganic salts, organic molecules with low molecular mass, free amino acids, small polypeptides, linear peptides, nucleotides, disulfide-rich peptides, enzymes, and high molecular mass proteins. Considering that there are still many species little-studied, this work aimed to analyze the venom of the mygalomorph spider Avicularia juruensis searching for new antimicrobial peptides. Using reverse-phase high-performance liquid chromatography, microbial growth inhibition assay, transcriptomics, and proteomics approaches we identified three antimicrobial peptides that were named Avilin, Juruin_2, and Juruenine. All of them showed similarities with neurotoxins that act on ion channels and, probably, they have the ICK motif in their structure. The ICK fold seems to be conserved in several venomous animal lineages and presents elevated functional diversity, as well as gives stability to the toxins. The study of animal venoms is of great importance to carry out the characterization of unknown components and that may have a biotechnological application (like the antimicrobial peptides), in special venoms from spiders that are from less studied families.

microbiology↗