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...

Whole-Genome sequencing of the schizomid arachnid Rowlandius potiguar Santos, Ferreira and Buzzato, 2013 from the caves of the Brazilian semiarid

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Image Credit: CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=40194191

Whole-Genome sequencing of the schizomid arachnid Rowlandius potiguar Santos, Ferreira and Buzzato, 2013 from the caves of the Brazilian semiarid

Abstract

Short-tailed whip scorpions (Arachnida: Schizomida) are a poorly studied group of arachnids, particularly in terms of genomic resources, despite their ecological and evolutionary relevance in subterranean environments. In this study, we present the first draft genome assembly of Rowlandius potiguar, a cave-associated species endemic to karst systems of northeastern Brazil. Genomic DNA was sequenced using Illumina paired-end technology (2 × 150 bp), and reads were assembled using a de novo assembly pipeline. The resulting genome assembly has a total length of 1.8 Gb, distributed across 1,505,104 scaffolds and 1,510,944 contigs, indicating a highly fragmented assembly. The scaffold N50 and contig N50 values were both 3.2 kb, and the GC content was 32.5%. Genome completeness was assessed using BUSCO with Arthropoda and Metazoa datasets. The Arthropoda analysis recovered 20.5% complete BUSCOs (19.1% single-copy and 1.5% duplicated), 53.0% fragmented, and 26.5% missing genes. Similarly, the Metazoa dataset identified 24.7% complete BUSCOs (23.4% single-copy and 1.4% duplicated), with 54.7% fragmented and 20.5% missing genes. The low BUSCO completeness and high proportion of fragmented genes reflect the highly fragmented nature of the assembly, likely resulting from the use of short-read sequencing technologies and the presence of repetitive genomic regions. Despite these limitations, this genome represents an important first genomic resource for Schizomida and provides a foundation for future studies on genome evolution, adaptation to subterranean environments, and the genetic basis of troglomorphic traits in arachnids.

Bezerra Dantas, Origilene, Matheus Arthur Lúcio da Rocha, Rodrigo Lopes Ferreira, et al. 2026. “Whole-Genome Sequencing of the Schizomid Arachnid Rowlandius Potiguar Santos, Ferreira and Buzzato, 2013 from the Caves of the Brazilian Semiarid.” Biodiversity Genomes, June 29. https://doi.org/10.56179/001c.164269.