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

Posted by
  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...

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

Posted by

 


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