Distinct pathophysiological mechanisms of Heterometrus laoticus and Lychas mucronatus scorpion venoms on cardiovascular and renal functions

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  Distinct pathophysiological mechanisms of Heterometrus laoticus and Lychas mucronatus scorpion venoms on cardiovascular and renal functions Abstract Background:    Heterometrus laoticus and Lychas mucronatus are widely distributed in Southeast Asia, yet their pathophysiological effects of both venoms remain poorly characterized due to low human fatality rates. This study compared their venom compositions and acute cardiovascular and renal effects. Methods:   Anesthetized male New Zealand White rabbits were monitored for blood pressure (BP), heart rate (HR), and renal clearance following intravenous administration of crude venom (0.5 mg/kg). Venom components were identified via LC-MS/MS, and hematological/biochemical parameters were assessed. Results:    H. laoticus venom induced a rapid, transient hypotension ( p < 0.05), followed by a mild, prolonged hypotensive phase (up to 120 min). Conversely, L. mucronatus venom elicited a biphasic response: ...

Shining a light on the photochemical stability of peptidic bioinsecticides

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Shining a light on the photochemical stability of peptidic bioinsecticides

Abstract

Peptide toxins from spider venoms are being increasingly hailed as environmentally friendly alternatives to market-dominating small-molecule chemical insecticides. While the stability of knotted spider-venom peptides towards enzymatic degradation, temperature changes and varying pH conditions has already been examined, their susceptibility to sunlight remains unclear. Field applications of insecticides demand that the insecticidal component is active for at least a few days to ensure sufficient eradication of the targeted insect pests. We therefore exposed four insecticidal spider venom peptides (ω-Hv1a, ω/κ-Hv1a, Ta1a and Dc1a) to continuous artificial sunlight for up to 7 days. After certain incubation periods, we quantified the percentage of intact peptide and identified sites of peptide cleavage. We found that after 3 days of continuous exposure (= 6 days of 12 h/d sunlight), the amount of remaining intact peptide was 16% (Ta1a), 21% (Dc1a), 55% (ω-Hv1a), and 67% (ω/κ-Hv1a), whereas bovine serum albumin was completely degraded. Even after 7 days (= 14 days of 12 h/d sunlight) exposure, more than 50% of ω/κ-Hv1a and ω-Hv1a remained intact. Peptides with lower molecular mass tended to be less susceptible to sunlight, while cleavage of peptide bonds involving proline or cysteine were most susceptible to photochemical degradation. The photochemical changes detected by mass spectrometry mainly comprised oxidations, deamidations, and cysteine-targeted modifications.
Herzig, V., Ahabh, A., Jones, A., & King, G. F. (2025). Shining a light on the photochemical stability of peptidic bioinsecticides. Toxicon, 108381. https://doi.org/10.1016/j.toxicon.2025.108381