Antimicrobial peptides (AMPs) are molecular factors in innate immunity and are believed to play a key role in invertebrate host defence. We identified theromacin (TM) from an Asian polychaeta, Perinereis linea, using de novo RNA-seq analysis. TM, a typical AMP of invertebrates, is a cysteine-rich AMP with five disulfide bonds consisting of ten cysteine residues. In gene expression analysis, TM genes were constantly upregulated after lipopolysaccharide (LPS) stimulation. In contrast, after peptidoglycan (PGN) stimulation, it was upregulated initially and downregulated after 12 h. We synthesized a peptide based on the macin AMP in the TM amino acid sequence. The synthetic peptide showed antibacterial activity against some Gram-positive and Gram-negative bacteria. Therefore, the AMPs of P. linea might have broad roles in host defence and exhibit different degrees of activity.

抗菌肽 (AMP) 是先天免疫的分子因子，被认为在无脊椎动物宿主防御中起关键作用。我们使用de novo RNA-seq 分析从亚洲多毛纲 Perinereis linea 中鉴定了theromacin (TM) 。TM 是一种典型的无脊椎动物 AMP，是一种富含半胱氨酸的 AMP，具有五个由 10 个半胱氨酸残基组成的二硫键。在基因表达分析中，TM 基因在脂多糖 (LPS) 刺激后不断上调。相反，在肽聚糖 (PGN) 刺激后，它最初上调，12 小时后下调。我们合成了基于 TM 氨基酸序列中的 macin AMP 的肽。合成肽对一些革兰氏阳性和革兰氏阴性细菌显示出抗菌活性。因此，AMPsP. linea可能在宿主防御中具有广泛的作用并表现出不同程度的活动。