Yoon Yoo Bin, Woo Ji Won, Jun Park Beom, Park Kihwan, Kang Sangwook, Chung David, Lee Dong Ho, Do Yuno, Park Soon Cheol, Cho Sung-Jin
Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea.
Department of Biological Sciences, Kongju National University, Gongju 32588, Republic of Korea.
J Invertebr Pathol. 2024 Nov;207:108234. doi: 10.1016/j.jip.2024.108234. Epub 2024 Nov 13.
Due to its significant bioconversion potential, the black soldier fly (BSF), Hermetia illucens, shows great promise as a cost-effective alternative for recycling biological waste. BSF larvae (BSFL) are constantly exposed high levels of pathogenic microorganisms, including bacteria and fungi, which endows BSFL with a robust immune system. Diptericin, a type of glycine-rich antimicrobial peptide (AMP) that exhibits activity against gram-negative bacteria, contains proline-rich domains (P-domains) and glycine-rich domains (G-domains); these domains are separated by a furin cleavage site. Although the presence and expression patterns of BSFL diptericins have been documented, their basic molecular properties remain unclear. To the best of our knowledge, in the present study, we report, for the first time, the molecular characteristics of seven full-length cDNA sequences of H. illucens diptericins and their expression patterns following challenges with gram-positive or gram-negative bacteria. Seven diptericin paralogs are located in tandem on chromosome 2, spanning a total length of 38.6 kb, with an average intergenic distance of approximately 5.5 kb. Sequence analysis revealed that three diptericins (HipDptA/B/C) are pseudogenized due to premature stop codons. In contrast, the other diptericins (HiDpt1/2/3/4) possess mature-sized G-domains rich in glycine at the C-terminus, which are essential for AMP activity, along with proline-rich domain (P-domain) in the N-terminal and either two (HiDpt1/2/3) or one (HiDpt4) putative furin cleavage sites (R-X-R/K-R) between these domains. These furin cleavage sites possibly produce a glycine-rich AMP and one or two additional peptides with unknown functions. Similar to other diptericins, the expression of HiDpt1/2/3/4 mRNAs is predominantly induced by gram-negative bacteria, increasing typically by ≥ 1,000-fold (up to 5,000-fold). Additionally, HiDpt1/3/4 show significant responses to gram-positive bacteria such as Micrococcus luteus, though not as strongly as to gram-negative bacteria. These findings suggest that HiDpts function as a rapid, effective, and broad-spectrum first-line defense mechanism in the BSFL immune system.
由于其显著的生物转化潜力，黑水虻（Hermetia illucens）作为一种具有成本效益的生物废物回收替代物展现出巨大前景。黑水虻幼虫（BSFL）持续暴露于高水平的致病微生物，包括细菌和真菌中，这赋予了BSFL强大的免疫系统。双翅肽是一种富含甘氨酸的抗菌肽（AMP），对革兰氏阴性菌具有活性，包含富含脯氨酸的结构域（P结构域）和富含甘氨酸的结构域（G结构域）；这些结构域由一个弗林蛋白酶切割位点隔开。尽管已经记录了BSFL双翅肽的存在和表达模式，但其基本分子特性仍不清楚。据我们所知，在本研究中，我们首次报道了黑水虻双翅肽七个全长cDNA序列的分子特征及其在受到革兰氏阳性或革兰氏阴性细菌攻击后的表达模式。七个双翅肽旁系同源基因串联位于2号染色体上，全长38.6 kb，平均基因间距离约为5.5 kb。序列分析表明，三个双翅肽（HipDptA/B/C）由于提前出现终止密码子而成为假基因。相比之下，其他双翅肽（HiDpt1/2/3/4）在C端具有富含甘氨酸的成熟大小的G结构域，这对AMP活性至关重要，在N端具有富含脯氨酸的结构域（P结构域），并且在这些结构域之间有两个（HiDpt1/2/3）或一个（HiDpt4）假定的弗林蛋白酶切割位点（R-X-R/K-R）。这些弗林蛋白酶切割位点可能产生一种富含甘氨酸的AMP和一种或两种功能未知的额外肽段。与其他双翅肽类似，HiDpt1/2/3/4 mRNA的表达主要由革兰氏阴性菌诱导，通常增加≥1000倍（高达5000倍）。此外，HiDpt1/3/4对革兰氏阳性菌如藤黄微球菌有显著反应，尽管不如对革兰氏阴性菌反应强烈。这些发现表明，HiDpts在BSFL免疫系统中作为一种快速、有效且广谱的一线防御机制发挥作用。
