First insular record and DNA barcoding of Euscorpius vailatii Tropea & Fet, 2015 from Trizonia Island (Fokida, Greece)

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  First insular record and DNA barcoding of Euscorpius vailatii Tropea & Fet, 2015 from Trizonia Island (Fokida, Greece) Abstract Euscorpius vailatii Tropea & Fet, 2015 (Scorpiones: Euscorpiidae), originally described from Aitoloakarnania and Fokida (Greece), is herein reported from Trizonia Island in the Gulf of Corinth, representing the first insular record for the species. The examined specimens are consistent with the diagnostic morphology of E. vailatii . The first molecular data for the species are provided, based on both mainland and insular populations. Comparative analyses further highlight the distinctiveness of E. vailatii from geographically close congeners, while phylogenetic results indicate a sister-taxon relationship with E. erymanthius , supporting a Quaternary biogeographic history shaped by the evolution of the Gulf of Corinth system. Kalaentzis, K., Frigioni, F., Panagiotopoulos, A., Tzoras, E., Minoudi, S., & Triantafyllidis, A. 2026 . First insul...

Predictive analysis of B-cell antigenic epitopes in phospholipase D toxins from Loxosceles spiders

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Predictive analysis of B-cell antigenic epitopes in phospholipase D toxins from Loxosceles spiders

Abstract

The Phospholipase D (PLD) toxin family, a major component of the Loxosceles spider venom, is a valuable biotechnological tool for developing antivenom treatment and diagnostic assays to overcome and prevent loxoscelism. However, there is limited knowledge about the antigenic structure of the PLD family or if sequence diversity correlates with antigenic variability. This study aimed to evaluate the possible antigenic diversity of PLDs sequences among different species of spiders of the Loxosceles genus through a predictive analysis of potential continuous and discontinuous antigenic epitopes of two phylogenetic interspecies clusters. Thus, L. laeta had higher amino acid sequence variation than other species, being classified into three phylogenetic clusters at the intra-specie level. Furthermore, multiple alignments of consensus PLD sequences from each Loxosceles species showed two different phylogenetic clusters at interspecies level depending on the amino acid conservation. For each cluster, at least nine continuous antigenic domains were identified, and depending on the phylogenetic cluster belonging to the Loxosceles species, the PLD continuous and discontinuous antigenic structure varies. Also, L. laeta PLDs vary significantly within the Loxosceles species and possess their own antigenic structure compared to other species with common continuous epitopes. Finally, the catalytic loop was identified as a common discontinuous epitope in the PLDs independently of the cluster or the class it belongs to. This antigenic diversity of PLD toxins could have implications for antibody recognition and should be considered in the design strategies for the development of serum treatments and diagnostic assays to detect Loxosceles venom.
Catalán, A., García, C., Sambra, V., Cadena, N., Rojas, J., Arán-Sekul, T., San Francisco, J., Vásquez-Saez, V., Muñoz, C., Vásquez, A., & Araya, J. E. (2025). Predictive analysis of B-cell antigenic epitopes in phospholipase D toxins from Loxosceles spiders. Toxicon: X, 26, 100222. https://doi.org/10.1016/j.toxcx.2025.100222