title: Characterization and function analysis of an anti-lipopolysaccharide factor (ALF) from the Chinese shrimp Fenneropenaeus chinensis.
abstract: Anti-lipopolysaccharide factor (ALF) is one of the widely-studied antimicrobial peptides (AMPs) with broad-spectrum antibacterial activity and antiviral property. Previous studies show the existence of multiform of ALFs in crustacean which are important for immunity of the animals. In the present study, we characterized one isoform of ALF from the Chinese shrimp Fenneropenaeus chinensis (FcALF2). Tissue distribution analysis revealed that FcALF2 showed the highest expression level in the lymphoid organ (Oka) of the shrimp. The expression level of FcALF2 in shrimp was significantly up-regulated when they were injected with Micrococcus lysodeikticus and Vibrio anguillarum. A peptide corresponding to the LPS-binding domain of FcALF2 (FcALF2-LBD) was synthesized to analyze its antimicrobial activities. Data demonstrated that FcALF2-LBD possessed strong antibacterial activity against Gram-positive bacteria Micrococcus luteus and M.lysodeikticus with MIC ranges of 2-4 μM and 1-2 μM respectively and significant inhibition activity against white spot syndrome virus (WSSV). The antibacterial activities of the sequence modified peptides (FcALF2-LBDb, FcALF2-LBDv) were apparently enhanced and broadened after the amount of basic amino acids was increased in the synthetic LPS-binding domain. These data provide more insights into understanding the function of LPS-binding domain of ALF and the role of ALF in shrimp immunity.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; National & Local Joint Engineering Laboratory of Ecological Mariculture, 7 Nanhai Road, Qingdao 266071, China.
authors.forename: Shihao
authors.initials: S
authors.lastname: Li
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Shuyue
authors.initials: S
authors.lastname: Guo
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; National & Local Joint Engineering Laboratory of Ecological Mariculture, 7 Nanhai Road, Qingdao 266071, China. Electronic address: fhli@qdio.ac.cn.
authors.forename: Fuhua
authors.initials: F
authors.lastname: Li
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
authors.forename: Jianhai
authors.initials: J
authors.lastname: Xiang
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D060829:Arthropod Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D015870:Gene Expression; D007113:Immunity, Innate; D008070:Lipopolysaccharides; D008826:Microbial Sensitivity Tests; D008837:Micrococcus / Q000187:drug effects / Q000276:immunology; D009928:Organ Specificity; D033561:Penaeidae / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D010802:Phylogeny; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D015854:Up-Regulation / Q000276:immunology; D014733:Vibrio / Q000187:drug effects / Q000276:immunology; D014779:Virus Replication; D046848:White spot syndrome virus 1 / Q000502:physiology
chemical_list: D023181:Antimicrobial Cationic Peptides; D060829:Arthropod Proteins; D008070:Lipopolysaccharides; D020033:Protein Isoforms
keywords: ALF; Antibacterial; Antiviral; LPS-binding domain; Penaeid shrimp