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...

Unveiling Neotropical Hadrotarsinae (Araneae: Theridiidae): new species and new records of Dipoena from South America

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Unveiling Neotropical Hadrotarsinae (Araneae: Theridiidae): new species and new records of Dipoena from South America

Abstract

Hadrotarsinae comprises a morphologically distinctive lineage of ant-eating comb-footed spiders whose diversity and generic limits remain poorly understood, particularly in the Neotropical region. Based on the examination of museum specimens using light and scanning electron microscopy, we describe four new species of Dipoena from Brazil: Dipoena vulsella sp. nov. from Bahia, Minas Gerais, and São Paulo; Dipoena albaspinosa sp. nov. from Espírito Santo; Dipoena farciminis sp. nov. from Bahia, Espírito Santo, and Minas Gerais; and Dipoena cicer sp. nov. from Bahia. We also describe one new species from Ecuador, Dipoena unobi sp. nov., from Napo Province. In addition, we provide new distribution records from Brazil and Ecuador for Dipoena atlantica Chickering, 1943, D. bryantae Chickering, 1943, D. cordiformis Keyserling, 1886, D. duodecimpunctata Chickering, 1943, D. ericae Rodrigues, 2013, D. granulata (Keyserling, 1886), D. hortoni Chickering, 1943, D. ira Levi, 1963, D. isthmia Chickering, 1943, D. kuyuwini Levi, 1963, D. plaumanni Levi, 1963, D. pumicata (Keyserling, 1886), D. santacatarinae Levi, 1963, D. santaritadopassaquatrensis Rodrigues, 2013, and Dipoenata balboae (Chickering, 1943). A comparative discussion of hadrotarsine morphology supports the conservative placement of all five new species in Dipoena and highlights the need for a comprehensive revision of generic limits within Hadrotarsinae.

Cardinali, J.V., Faleiro, B.T. & Santos, A.J. (2026) Unveiling Neotropical Hadrotarsinae (Araneae: Theridiidae): new species and new records of Dipoena from South America. Zootaxa, 5875 (2), 101–143. https://doi.org/10.11646/zootaxa.5875.2.1