Computational engineering of the scorpion venom peptide Ttap3 enhances membrane selectivity and antimicrobial potential

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  Computational engineering of the scorpion venom peptide Ttap3 enhances membrane selectivity and antimicrobial potential Abstract Venom-derived antimicrobial peptides (AMPs) are promising scaffolds for next-generation antimicrobial agents because of their structural diversity and membrane-targeting mechanisms. Ttap3, a peptide isolated from scorpion venom, exhibits weak antimicrobial activity despite possessing characteristic amphipathic features associated with membrane-active peptides. This study employed a computational engineering strategy to redesign Ttap3 and investigate how sequence modifications influence membrane selectivity and antimicrobial potential. Structural modelling showed that Ttap3 adopted a predominantly α-helical amphipathic conformation with moderate hydrophobic moment and relatively high hydrophobicity. Molecular dynamics simulations demonstrated preferential interaction with bacterial membrane models relative to mammalian membranes, although measurable inte...

The genomic consequences and persistence of sociality in spiders

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The genomic consequences and persistence of sociality in spiders

Abstract

In cooperatively breeding social animals, a few individuals account for all reproduction. In some taxa, sociality is accompanied by a transition from outcrossing to inbreeding. In concert, these traits reduce effective population size, potentially rendering transitions to sociality ‘evolutionarily dead-ends’. We addressed this hypothesis in a comparative genomic study in spiders, where sociality has evolved independently at least 23 times, but social branches are recent and short. We present genomic evidence for the evolutionary dead-end hypothesis in a spider genus with three independent transitions to sociality. We assembled and annotated high-quality, chromosome-level reference genomes from three pairs of closely related social and subsocial Stegodyphus species. We timed the divergence between the social and subsocial species pairs to be from 1.3 to 1.8 million years. Social evolution in spiders involves a shift from outcrossing to inbreeding and from equal to female-biased sex ratio, causing severe reductions in effective population size and decreased efficacy of selection. We show that transitions to sociality only had full effect on purifying selection at 119, 260 and 279 kya respectively, and follow similar convergent trajectories of progressive loss of diversity and shifts to an increasingly female-biased sex ratio. This almost deterministic genomic response to sociality may explain why social spider species do not persist. What causes species extinction is not clear, but could be either selfish meiotic drive eliminating the production of males, or an inability to retain genome integrity in the face of extremely reduced efficacy of selection.

The genomic consequences and persistence of sociality in spiders, Jilong Ma, Jesper Bechsgaard, Anne Aagaard, et al. Genome Res. published online February 20, 2025. Access the most recent version at doi:10.1101/gr.279503.124 https://genome.cshlp.org/content/early/2025/02/19/gr.279503.124#