Electrophysiological Characterization of the Venom and Toxins from the Scorpion Tityus championi Targeting Voltage-Gated Sodium Channels and Molecular Modeling of Tch3, a Toxin with Therapeutic Potential for Pain Relief

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  Electrophysiological Characterization of the Venom and Toxins from the Scorpion Tityus championi Targeting Voltage-Gated Sodium Channels and Molecular Modeling of Tch3, a Toxin with Therapeutic Potential for Pain Relief Abstract Scorpion neurotoxins are small peptides that target ion channels and offer opportunities for novel therapeutic discovery. This study analyzed the functional effects of the venom and toxins from the Costa Rican endemic scorpion,  Tityus championi . Initially, crude venom was tested on different isoforms of voltage-gated sodium channels. Our findings revealed that the venom contains toxins that affect mammalian Na V 1.6 and Na V 1.7, as well as the cockroach BgNa V 1 channel. Increased currents through Na V 1.6 and BgNa V 1 channels were associated with bigger window currents and inhibition of inactivation. Decreased Na V 1.7 currents were associated with smaller conductance. Crude venom and TCh3 toxin inhibited action potential generation in invertebr...

Dysdera parthenogenetica sp. nov. (Araneae, Dysderidae): A Unique Case of Parthenogenesis in Spiders

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Dysdera parthenogenetica sp. nov. (Araneae, Dysderidae): A Unique Case of Parthenogenesis in Spiders

Abstract

We studied the parthenogenetic lineages of the spider Dysdera hungarica (Araneae: Dysderidae). Based on our data, we consider them to constitute a separate taxon, Dysdera parthenogenetica sp. nov. Morphologically, the new species differs mainly by slightly reduced female copulatory organs. The ovaries contain meiotic cells, suggesting that automictic thelytoky occurs in this species. D. parthenogenetica sp. nov. colonised areas west of the ancestral sexual species D. hungarica, especially the Pannonian region; the distribution areas of these species show minimal overlap. The distribution pattern of D. parthenogenetica sp. nov. suggests that the obligate thelytoky in this species originated through geographic thelytoky. D. parthenogenetica sp. nov. has been found in a significantly larger variety of habitats than D. hungarica, including agroecosystems. Therefore, the parthenogenesis of D. parthenogenetica sp. nov. is associated with the ability to populate even habitats without tree or bush cover, often disturbed, which is unfavourable for other Dysdera species. According to the analysis of selected nuclear (ITS2) and mitochondrial markers (COI), D. parthenogenetica sp. nov. showed low genetic diversity (single COI haplotype and two closely related ITS2 haplotypes) in contrast to the ancestral D. hungarica. By separation of D. parthenogenetica sp. nov., D. hungarica becomes a paraphyletic species. D. hungarica is thus one of the first documented cases of paraspecies among spiders. Although D. parthenogenetica sp. nov. exhibits minimum genetic variation at the analysed molecular markers, it displays considerable karyotype diversity. The transition to parthenogenesis was accompanied by a decrease in diploid number through chromosome fusions. Karyotypes of D. parthenogenetica sp. nov. diverged considerably from those of D. hungarica. Potential hybrids between these species would likely produce gametes with defective genomes. There is also a behavioural barrier between these two taxa. Females of D. parthenogenetica sp. nov. refuse to mate.

Řezáč, M., Král, J., Ávila Herrera, I. M., Forman, M., Řezáčová, V., Gloríková, N., & Heneberg, P. (2025). Dysdera parthenogenetica sp. Nov. (Araneae, Dysderidae): A Unique Case of Parthenogenesis in Spiders. Journal of Zoological Systematics and Evolutionary Research, 2025(1), 9266860. https://doi.org/10.1155/jzs/9266860