Antimicrobial peptides (AMPs) are the frontline innate defense system evolutionarily preserved in insects to combat invading pathogens. These AMPs could serve as an alternative to classical antibiotics to overcome the burden of treating multidrug resistant bacteria. Psacotheasin, a knottin type AMP was isolated from Psacothea hilaris and shown to exhibit antimicrobial activity, especially against fungi through apoptosis mediated cell death. In this study, we aimed to identify novel probable AMPs from Psacothea hilaris, the yellow spotted longicorn beetle. The beetle was immunized with the two bacterial strains (E. coli and S. aureus), and the yeast strain C. albicans. After immunization, total RNA was isolated and sequenced in Illumina platform. Then, beetle transcriptome was de novo assembled and searched for putative AMPs with the known physiochemical features of the AMPs. A selection of AMP candidates were synthesized and tested for antimicrobial activity. Four peptides showed stronger activity against E. coli than the control AMP, melittin while one peptide showed similar activity against S. aureus. Moreover, four peptides and two peptides showed antifungal activity stronger than and similar to melittin, respectively. Collectively one peptide showed both antibacterial and antifungal activity superior to melittin; thus, it provides a potent antimicrobial peptide. All the peptides showed no hemolysis in all the tested concentrations. These results suggest that in silico mining of insects’ transcriptome could be a promising tool to obtain and optimize novel AMPs for human needs.

中文翻译：

---

Psacothea hilaris的转录组分析：从头组装和抗菌肽的预测。

抗菌肽（AMPs）是进化上保存在昆虫中以抵抗入侵的病原体的一线先天防御系统。这些AMP可以替代传统抗生素，从而克服治疗多重耐药细菌的负担。从喜树（Psacothea hilaris）分离出结蛋白（AMP）结蛋白（Psacotheasin），并显示出抗菌活性，尤其是通过凋亡介导的细胞死亡来对抗真菌。在这项研究中，我们旨在从黄色斑点的longicorn甲虫Psacothea hilaris中鉴定出可能的新型AMP 。用两种细菌菌株（大肠杆菌和金黄色葡萄球菌）和酵母菌株白色念珠菌对甲虫进行免疫。。免疫后，分离总RNA，并在Illumina平台上测序。然后，从头组装甲虫转录组，并搜索具有AMP已知理化特性的推定AMP。合成了一些AMP候选物，并测试了其抗菌活性。四种肽对大肠杆菌的活性比对照AMP和蜂毒肽强，而一种肽对金黄色葡萄球菌的活性相似。。此外，四种肽和两种肽分别显示出比蜂毒肽更强的抗真菌活性。总的来说，一种肽的抗菌和抗真菌活性均优于蜂毒肽。因此，它提供了有效的抗菌肽。在所有测试浓度下，所有肽均无溶血现象。这些结果表明，在计算机上对昆虫的转录组进行计算机挖掘可能是获得和优化满足人类需求的新型AMP的有前途的工具。