Activity Determinants in Linear Spider Venom Peptide Fragments Against MRSA

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  Activity Determinants in Linear Spider Venom Peptide Fragments Against MRSA Abstract Objective: Using neural networks, we previously identified linear fragments of spider venom peptides active against methicillin-resistant Staphylococcus aureus (MRSA). Among them, peptide IX (IWLSLMKFAGKHL-NH 2 ) with a C -terminal amide displayed high antibacterial potency, whereas its non-amidated analogue, peptide X, was inactive. Peptide IX incorporates into zwitterionic multilamellar liposomes of dioleoylphosphatidylcholine (DOPC) without disrupting them, and also into anionic liposomes of dioleoylphosphatidylglycerol (DOPG) mimicking the MRSA cell membrane, leading to bilayer disruption. This study aims to elucidate the reasons for peptide X inactivation.  Methods: According to ¹H NMR spectroscopy, peptide X in water is governed by the ionization of the His12 residue. ³¹P NMR data show that peptide X interacts with DOPC and DOPG membranes. Monte Carlo simulations revealed conformati...

A new species of Harpactocrates Simon, 1914 (Araneae: Dysderidae) from Cantabria, Spain

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A new species of Harpactocrates Simon, 1914 (Araneae: Dysderidae) from Cantabria, Spain

Abstract 

A new species of Harpactocrates Simon, 1914 is described from Cantabria, northern Spain as Harpactocrates trenti sp. n. The species is closely related to H. ravastellus Simon, 1914, but can readily be distinguished by the more globular tegulum and a longer, hook-shaped embolus. Female specimens also show a characteristic configuration of the valve folds, visible through the cuticle as two anteriorly diverging lines. Detailed morphological descriptions, images of genital structures, and distribution data are provided. The discovery of H. trenti sp. n. increases the known Iberian representatives of the genus to nine species and highlights the need for further sampling in poorly surveyed regions, where additional undescribed taxa may occur.

Narro-Martín, A. J. (2026). A new species of Harpactocrates Simon, 1914 (Araneae: Dysderidae) from Cantabria, Spain. Arachnology 20(5): 693-698.