Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain

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  Hidden diversity in plain sight: four new species of Nemesia (Araneae: Mygalomorphae) from the Córdoba Province of Spain Abstract A taxonomic revision of the species of Nemesia Audouin, 1826, distributed in the vicinity of Córdoba City, southern Spain, is presented. Four new species are described: Nemesia morana sp. nov. (female), N. kodama sp. nov. (male and female), N. rosae sp. nov. (male and female), and N. tamajoni sp. nov. (male and female). These species are distinguished by distinct morphological characters, including the shape of the spermathecae, palpal bulbs, and spinnerets, as well as by burrow architecture. Fieldwork was conducted across two of the three major habitat types in the region—the humid, forested mountains of Sierra Morena and the croplands and riparian forests of the Guadalquivir Valley—while the third, the “campiña”, which is mainly composed of agricultural landscapes, remains poorly explored. Sampling methods included pitfall trapping and the direct e...

A novel scorpine-like peptide from the amazonian scorpion Brotheas amazonicus with cytolytic activity

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A novel scorpine-like peptide from the amazonian scorpion Brotheas amazonicus with cytolytic activity

Abstract


Introduction: 

Scorpion venoms contain bioactive molecules with potential antitumor properties. This study aimed to evaluate the cytotoxic effects of crude Brotheas amazonicus venom (BamazV) and its molecular weight–separated fractions on human breast cancer cell lines, with a focus on identifying active compounds and elucidating their mechanisms of action.


Methods: 

Human breast epithelial (MCF10A) and breast cancer cell lines (SKBR3, MCF7, and MDA-MB-231) were first assessed for dose-dependent responses to paclitaxel, a standard chemotherapeutic agent. BamazV was fractionated by ultrafiltration into >10 kDa, 3–10 kDa, and <3 kDa fractions, which were tested for cytotoxic activity. The active fraction underwent reversed-phase chromatography, and the major bioactive peptide was characterized by mass spectrometry and Edman degradation. Cytotoxic mechanisms were investigated using cell death assays.


Results: 

All cell lines showed a dose-dependent response to paclitaxel. Crude BamazV induced significant cytotoxicity at concentrations ≥ 50 μg/mL, with triple-negative MDA-MB-231 cells being the most sensitive. The >10 kDa fraction retained cytotoxic activity, leading to the isolation of a major peptide, BamazScplp1. Sequence analysis revealed 46–55% identity and 74–81% similarity to known scorpine-like peptides. Functional assays indicated that BamazScplp1 induced predominantly necrotic cell death, consistent with the activity profile of previously reported cytolytic scorpine-like molecules.


Discussion: 

These findings identify BamazScplp1 as a scorpine-like peptide with selective cytotoxicity toward triple-negative breast cancer cells, underscoring the potential of B. amazonicus venom as a source of bioactive compounds for cancer research.


Reis, M. B., Martins, J. G., Wiezel, G. A., Cipriano, U. G., Deperon Bonato, V. L., & Arantes, E. C. (2025). A novel scorpine-like peptide from the amazonian scorpion Brotheas amazonicus with cytolytic activity. Frontiers in Pharmacology, 16, 1652614. https://doi.org/10.3389/fphar.2025.1652614