Spider venom peptides Ht1a and Gg1a are toxic to honeybee parasite Varroa destructor by topical application

Posted by
  Spider venom peptides Ht1a and Gg1a are toxic to honeybee parasite Varroa destructor by topical application Abstract Global food supply strongly depends on honeybee pollination services, which are threatened by insecticides and pests such as parasitic Varroa destructor mites. Chemical varroacides/acaricides are hampered by resistance development, necessitating the development of sustainable and environmentally friendly alternatives, with arthropod venom peptides being considered promising sources of acaricidal toxins. With only a few acaricidal venom peptides being reported, we performed a systematic topical screening of 50 arthropod venoms against V. destructor , with 78% of the venoms causing 100% mortality after 24 h. Deconvolution of the venoms from the Tasmanian cave spider Hickmania troglodytes and the Giant Japanese funnel-web spider Gigathele gigas led to identification of the varroacidal peptides Ht1a and Gg1a. Topical application of Ht1a and Gg1a reduced varroa mite ...

Targeting cobra venom cytotoxin: a linear 40-mer ssDNA aptamer-based antivenom confers neutralisation potentials against cobra venom-induced cytotoxicity

Posted by

 


Targeting cobra venom cytotoxin: a linear 40-mer ssDNA aptamer-based antivenom confers neutralisation potentials against cobra venom-induced cytotoxicity

Abstract

Cytotoxin (CTX) is one of the major cobra venom components that contributes to dermonecrosis due to its cytotoxicity. However, current antibody-based antivenoms exert limited neutralisation effects against CTX-induced dermonecrosis. This study focused on discovering aptamer-based antivenom that specifically targets CTX, using repetitive centrifugation-based Systematic Evolution of Ligands by EXponential enrichment (SELEX) selection approach and Illumina amplicon next-generation sequencing. A total of 12 repetitive centrifugation-based selection rounds including a negative selection between rounds 7 and 8 were performed. This was followed by amplicon next-generation sequencing and sequencing bioinformatics workflow to analyse the abundance and persistence of the CTX-binding candidates. Sequences with log10 read counts of 2–3 with a round representation of 3–4 were selected as the final candidates. A linear and single-stranded DNA, 40T, was discovered and it exhibited high binding affinity and specificity to CTX with dissociation constant (KD) of 0.33–0.41 µM, as demonstrated by direct and competitive enzyme-linked aptamer assay (ELAA). 40T acquired a ‘sandwich’ configuration binding to CTX at the functional epitopes. It exhibited neutralisation potency against the CTX-induced cytotoxicity with EC50 of 0.47 µM. To mimic the real envenomation situation, venoms from Naja sputatrix, Naja siamensis, and Naja sumatrana were used to induce experimentally envenomed model for treatment with 40T. 40T demonstrated notable cell viability-restoring effects against these venoms at low micromolar ratios. These findings suggested a modified selection and sequencing workflow to discover the potential of 40T as aptamer-based antivenom to mitigate venom-induced dermonecrosis.

Hiu, J.J., Tan, H.S. & Yap, M.K.K. Targeting cobra venom cytotoxin: a linear 40-mer ssDNA aptamer-based antivenom confers neutralisation potentials against cobra venom-induced cytotoxicity. Arch Toxicol (2025). https://doi.org/10.1007/s00204-025-04211-z