Biotechnology Centre of Azores (CBA), Faculty of Sciences and Technology, University of the Azores, Açores, 9500-321 Ponta Delgada, Portugal.
NORCE Norwegian Research Centre, Nygårdstangen, 5838 Bergen, Norway.
Toxins (Basel). 2022 Nov 2;14(11):754. doi: 10.3390/toxins14110754.
Entomopathogenic nematodes are used as biological control agents against a broad range of insect pests. We ascribed the pathogenicity of these organisms to the excretory/secretory products (ESP) released by the infective nematode. Our group characterized different virulence factors produced by that underlie its success as an insect pathogen. A novel ShK-like peptide (ScK1) from this nematode that presents high sequence similarity with the ShK peptide from a sea anemone was successfully produced recombinantly in . The secondary structure of ScK1 appeared redox-sensitive, exhibiting a far-UV circular dichroism spectrum consistent with an alpha-helical secondary structure. Thermal denaturation of the ScK1 allowed estimating the melting temperature to 59.2 ± 0.1 °C. The results from toxicity assays using as a model show that injection of this peptide can kill insects in a dose-dependent manner with an LD of 16.9 µM per adult within 24 h. Oral administration of the fusion protein significantly reduced the locomotor activity of insects after 48 h ( < 0.05, Tukey's test). These data show that this nematode expresses insecticidal peptides with potential as next-generation insecticides.
昆虫病原线虫被用作防治广泛的昆虫害虫的生物防治剂。我们将这些生物体的致病性归因于感染性线虫释放的排泄/分泌产物 (ESP)。我们的小组对 产生的不同毒力因子进行了表征，这些因子是其作为昆虫病原体成功的基础。从这种线虫中成功地重组生产了一种新型的 ShK 样肽 (ScK1)，它与来自海葵的 ShK 肽具有很高的序列相似性。ScK1 的二级结构表现出氧化还原敏感性，呈现出与α-螺旋二级结构一致的远紫外圆二色性光谱。ScK1 的热变性允许估计其熔点为 59.2 ± 0.1°C。使用 作为模型的毒性测定结果表明，该肽注射可以以剂量依赖性方式杀死昆虫，每只成年昆虫的 LD 在 24 小时内为 16.9 µM。融合蛋白的口服给药在 48 小时后显著降低了昆虫的运动活性（<0.05，Tukey 检验）。这些数据表明，这种线虫表达具有作为下一代杀虫剂潜力的杀虫肽。
