文献类型： 外文期刊

作者： Zhang, Dong Ling ¹ ; Lv, Chang Huan ¹ ; Yu, Da Hui ² ; Wang, Zhi Yong ¹ ;

作者机构： 1.Jimei Univ, Minist Agr, Coll Fisheries, Key Lab Hlth Mariculture East China Sea, Xiamen 361021, Peoples R China

2.Chinese Acad Fishery Sci, South China Sea Fisheries Res Inst, South China Sea Resource Exploitat & Protect Coll, Guangzhou 510300, Guangdong, Peoples R China

关键词： Galectin;Marine fish;Secrete;Agglutination;Immunohistochemistry

期刊名称：FISH & SHELLFISH IMMUNOLOGY （ 影响因子：4.581； 五年影响因子：4.851 ）

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收录情况： SCI

摘要： Galectins are a family of endogenous lectins with beta-galactosides affinity, playing significant roles in the innate immunity of vertebrates and invertebrates. In this report, a new galectin-9 cDNA was identified and characterized in large yellow croaker Larimichthys crocea (designated as LcGal-9). The complete cDNA sequence of LcGal-9 was 1795 bp, with an open reading frame (ORF) of 1032 bp encoding 343 amino acids. The putative LcGal-9 protein contained two carbohydrate recognition domains (CRDs) connected by a linker peptide, with each carrying two conserved beta-galactoside binding motifs H-NPR and WG-EE-, and it possessed neither a signal peptide nor a transmembrane domain. LcGal-9 protein shared 43-74% identity with galectin-9 sequences from other species. The qRT-PCR analysis revealed that LcGal-9 mRNA was constitutively expressed in all tissues examined, predominately expressed in liver, spleen, gill, kidney, head-kidney and intestine. Western blot analysis showed that LcGal-9 protein was highly expressed in liver, spleen, intestine, kidney, head-kidney, skin, gill, and heart, but not detected in muscle and plasma. LcGal-9 mRNA transcripts were induced by poly I:C in the liver (from 6 h to 48 h), spleen (at 12 h) and head-kidney (at 12 h and 24 h). In contrast, Vibrio parahaemolyticus caused a significant down regulation in these three tissues, except for in spleen of 48 h and head-kidney of 3 h. Post-infection with Cryptocaryon irritans, the transcripts were dramatically up-regulated in gill, skin, spleen and head-kidney during initial infection period, while significant down-regulation afterward was also observed both in spleen and head-kidney. The recombinant LcGal-9 (named as rLcGal-9) purified from Escherichia coli BL21 (DE3) demonstrated hemagglutination against human, rabbit and L. crocea in a Ca2+-independent manner, which was inhibited by alpha-Lactose and LPS. The results of bacterial agglutination assays showed that rLcGal-9 was able to agglutinate Gram-negative bacteria V alginolyticus and Aeromonas hydrophila in a Ca2+-independent manner. By immunohistochemistry assay, significant increases of LcGal-9 protein appeared in the spleen stimulated with poly I:C (for 12 h) and V. parahaemolyticus (for 48 h) compared with the control. Based on the collective data, LcGal-9 might play an important role in innate immune responses, especially defense against Gram-negative bacteria in L. crocea. (C) 2016 Elsevier Ltd. All rights reserved.