Abstract：
Microbial drug resistance is becoming increasingly severe due to antibiotic abuse. The development and utilization of antimicrobial peptides is one of the important ways to solve this difficult problem. Crustins are a family of antimicrobial peptides that play important roles in the innate immune system of crustaceans. Several types of crustins exist in shrimp and their activities vary greatly. In the present study, we studied the immune function of one newly identified crustin and found that the type VI crustin encoding gene in Litopenaeus vannamei (LvCrustinVI) was mainly expressed in gills. Its expression was significantly up-regulated after Vibrio parahaemolyticus infection and knockdown of the gene promoted Vibrio proliferation in the hepatopancreas of shrimp, indicating that LvCrustinVI was involved in pathogens infection. The recombinant LvCrustinVI (rLvCrustinVI) showed strong inhibitory activities against both Gram-negative and Gram-positive bacteria, and exhibited binding activities with the bacteria and bacterial polysaccharides including Glu, LPS and PGN. In the presence of Ca2+, rLvCrustinVI showed a strong agglutination effect on V. parahaemolyticus and could significantly enhance the phagocytic ability of shrimp hemocytes against V. parahaemolyticus. In conclusion, LvCrustinVI played important roles as antimicrobial peptide and opsonin in the innate immune defense of L. vannamei. The study enriched our understanding of the functional activity of Crustin and provides an important basis for the development and utilization of antimicrobial peptides.
摘要：
由于抗生素的滥用,微生物耐药性变得越来越严重。开发和利用抗菌肽是解决这一难题的重要途径之一。地壳素是一类抗菌肽，在甲壳类动物的先天性免疫系统中起重要作用。虾中存在几种类型的地壳，它们的活性差异很大。在本研究中,我们研究了一种新鉴定的crustin的免疫功能，发现凡纳滨对虾（LvCrustinVI）中的VI型crustin编码基因主要在the中表达。副溶血性弧菌感染后其表达显著上调，敲除该基因促进了虾肝胰腺中弧菌的增殖，表明LvCrustinVI参与了病原体感染。重组LvCrustinVI(rLvCrustinVI)对革兰氏阴性菌和革兰氏阳性菌均表现出较强的抑制活性,并表现出与细菌和包括Glu在内的细菌多糖的结合活性，LPS和PGN。在Ca2+的存在下，rLvCrustinVI对副溶血性弧菌具有很强的凝集作用，能显著增强对虾血细胞对副溶血性弧菌的吞噬能力。总之,LvCrustinVI作为抗菌肽和调理素在凡纳滨对虾先天免疫防御中发挥重要作用。该研究丰富了人们对Crustin功能活性的认识,为抗菌肽的开发利用提供了重要依据。
