Liao Chunli, Huang Ran, Yang Yi, Huang Yapeng, Zhang Kai, Ma Liang, Li Taotao, Wang Lianzhe, Zhang Huamin, Li Bingbing
College of Life Science and Engineering, Henan University of Urban Construction, Pingdingshan, Henan, China.
Center of Healthy Food Engineering and Technology of Henan, Henan University of Urban Construction, Pingdingshan, Henan, China.
Front Microbiol. 2023 May 9;14:1154811. doi: 10.3389/fmicb.2023.1154811. eCollection 2023.
produces insecticidal proteins capable of causing toxicity in pests, but the insecticidal mechanisms of these proteins for insect control remain unclear. To elucidate the mechanisms, the purified insecticidal protein from NK was administered to larvae either by intraperitoneal injection or by feeding. The number of hemocytes, apoptosis in immune cells, and polyphenol oxidase (PO) activity of larvae were detected by hemocytometer, Annexin V-FITC/PI, and UV-vis spectrophotometer, respectively. With the extension of the invasion time of NK insecticidal protein, the number of hemocytes in larvae decreased significantly ( < 0.05), whereas the apoptosis rate of hemocytes increased. The activity of PO showed a trend of rising-peak-sharp decline and the melanization reaction was deepened simultaneously. Moreover, the phagocytosis and coating capabilities of hemocytes decreased, and the intraperitoneal injection method was more effective than the feeding method. Taking together, the insecticidal protein of NK inhibits and destroys the cellular immune response of larvae, which suggests an important role in killing the host insect.
能产生对害虫具有毒性的杀虫蛋白，但这些蛋白用于昆虫防治的杀虫机制仍不清楚。为阐明其机制，将从NK中纯化得到的杀虫蛋白通过腹腔注射或喂食的方式施用于幼虫。分别通过血细胞计数器、膜联蛋白V-异硫氰酸荧光素/碘化丙啶以及紫外可见分光光度计检测幼虫的血细胞数量、免疫细胞凋亡情况和多酚氧化酶（PO）活性。随着NK杀虫蛋白侵入时间的延长，幼虫体内的血细胞数量显著减少（<0.05），而血细胞的凋亡率增加。PO的活性呈现出上升-峰值-急剧下降的趋势，同时黑化反应加深。此外，血细胞的吞噬和包被能力下降，且腹腔注射法比喂食法更有效。综上所述，NK的杀虫蛋白抑制并破坏了幼虫的细胞免疫反应，这表明其在杀死宿主昆虫中发挥着重要作用。
