Jiang Hai-Shan, Zhang Qing, Zhao Yan-Ran, Jia Wen-Ming, Zhao Xiao-Fan, Wang Jin-Xing
MOE Key Laboratory of Plant Cell Engineering and Germplasm Innovation/Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, China.
MOE Key Laboratory of Plant Cell Engineering and Germplasm Innovation/Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, China.
Dev Comp Immunol. 2015 Jan;48(1):33-42. doi: 10.1016/j.dci.2014.09.001. Epub 2014 Sep 15.
Anti-lipopolysaccharide factors (ALFs) are a group of critical effector molecules with a broad spectrum of antimicrobial activities in crustaceans. Four groups of ALFs (A, B, C, and D) have been identified in peneaid shrimp. In the study, we identified a new group of ALFs (designated as MjALF-E) from Marsupenaeus japonicus. This new group (group E) included MjALF-E1 and E2. MjALF-E1 was highly expressed in hemocytes, heart, and intestine, whereas E2 was highly expressed in gills, stomach, and intestine. Expressions of both MjALF-E1 and E2 were upregulated by bacterial challenge. Synthesized LPS-binding domain peptides of MjALF-E1 and E2 strongly bind to bacterial cell wall components lipopolysaccharide (LPS) and peptidoglycan (PGN). The recombinant rMjALF-E2 showed relatively weak binding activity to LPS and PGN. Both synthesized peptides and rMjALF-E2 exhibited antimicrobial activity against Gram-negative bacteria, whereas rMjALF-E2 could promote the clearance of bacteria in vivo. After knockdown of MjALF-E2 and infection with Vibrio anguillarum, shrimp showed high and rapid mortality compared with GFPi shrimp. These results suggest that MjALF-Es serves a protective function against bacterial infection in shrimp.
抗脂多糖因子（ALFs）是甲壳类动物中一组具有广泛抗菌活性的关键效应分子。在对虾中已鉴定出四组ALFs（A、B、C和D）。在本研究中，我们从日本囊对虾中鉴定出一组新的ALFs（命名为MjALF-E）。这一新组（E组）包括MjALF-E1和E2。MjALF-E1在血细胞、心脏和肠道中高表达，而E2在鳃、胃和肠道中高表达。细菌刺激后，MjALF-E1和E2的表达均上调。MjALF-E1和E2的合成脂多糖结合域肽与细菌细胞壁成分脂多糖（LPS）和肽聚糖（PGN）强烈结合。重组rMjALF-E2对LPS和PGN的结合活性相对较弱。合成肽和rMjALF-E2均对革兰氏阴性菌具有抗菌活性，而rMjALF-E2可促进体内细菌的清除。MjALF-E2基因敲低后感染鳗弧菌，与注射绿色荧光蛋白干扰片段（GFPi）的对虾相比，对虾表现出高死亡率且死亡迅速。这些结果表明，MjALF-Es在对虾抵抗细菌感染中发挥保护作用。
