Rational attenuation of elapid long-chain neurotoxin by targeted residue substitution and disulfide architecture simplification: implications for receptor interaction and immune recognition

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  Rational attenuation of elapid long-chain neurotoxin by targeted residue substitution and disulfide architecture simplification: implications for receptor interaction and immune recognition Abstract Elapid long-chain neurotoxins (LNTxs) exert their toxicity through high-affinity binding to nicotinic acetylcholine receptors (nAChRs). Specific residues mediate this process, including basic (Lys23, Arg33, Arg36, Lys49), structural (Cys26, Cys30), and aromatic (Phe29) amino acids. To investigate the functional and immunogenic implications of modifying these residues, we designed two recombinant variants of a consensus LNTx. The first variant, rLcNTx V1, contains charge-reversal mutations at four key basic positions, while the second, rLcNTx V2, lacks the segment corresponding to the fifth disulfide bond. We expressed both variants in Escherichia coli Origami cells. rLcNTx V1 was recovered in a soluble form, but rLcNTx V2 was present only in inclusion bodies. We assessed the binding ...

New insights into Damarchus: a new species and gynandromorph description from Thailand (Araneae: Bemmeridae)

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New insights into Damarchus: a new species and gynandromorph description from Thailand (Araneae: Bemmeridae)

Abstract

The genus Damarchus Thorell, 1891, represents a relatively neglected group of mygalomorph spiders distributed across several Asian countries, including India, Indonesia, Malaysia, Myanmar, Singapore, and Thailand. This study describes a new species, Damarchus inazuma sp. nov., discovered in Thailand. The male D. inazuma is identified by the presence of three diminutive spines on the tibial apophysis, whereas the female is characterized by an elongated spermathecal stalk that exhibits an inward curvature. Additionally, we report the identification of a gynandromorph specimen of D. inazuma, marking the first recorded instance of this condition within the family Bemmeridae.

Kunsete, C., Thanoosing, C., Sivayyapram, V., Traiyasut, P. & Warrit, N. (2025) New insights into Damarchus: a new species and gynandromorph description from Thailand (Araneae: Bemmeridae). Zootaxa, 5696 (3), 409–424. https://doi.org/10.11646/zootaxa.5696.3.6