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Galectin, another lectin from Fenneropenaeus merguiensis contributed in shrimp immune defense. J Invertebr Pathol 2022; 190:107738. [PMID: 35247464 DOI: 10.1016/j.jip.2022.107738] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 01/24/2022] [Accepted: 02/27/2022] [Indexed: 01/12/2023]
Abstract
Numerous lectins act as pattern recognition receptors (PRRs) in the innate immune system of invertebrates. Here, a galectin (FmGal) was isolated from hemocytes of Fenneropenaeus merguiensis. FmGal contained one open reading frame encoding a peptide of 338 amino acids. The primary sequence of FmGal comprised a carbohydrate recognition domain with a specific galactose binding site. The FmGal transcripts were found mostly in hemocytes of healthy shrimp. The expression of FmGal was up-regulated upon challenge with Vibrio parahaemolyticus and white spot syndrome virus (WSSV). Gene-silencing with FmGal double-stranded RNA resulted in extreme down-regulation of FmGal. Knockdown with a co-injection of pathogens reduced the survival rate of shrimp. Recombinant protein of FmGal (rFmGal) required Ca2+ to agglutinate pathogenic bacteria and exhibited sugar-specificity to galactose, lactose, lipopolysaccharide (LPS) and lipoteichoic acid (LTA). The ELISA-validated binding of rFmGal revealed higher affinity to LTA than LPS. rFmGal did not exhibit antibacterial activity but could enhance the phagocytosis and encapsulation of pathogenic invaders by hemocytes. Encapsulation was suppressed by galactose and lactose. Moreover, rFmGal also promoted the in vivo clearance of V. parahaemolyticus. FmGal, a galectin in F. merguiensis, participated in shrimp immunity, functioning as a PRR which might be involved in certain cellular responses.
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Liu Y, Su Y, Zhang A, Cui Z. A C-Type Lectin Highly Expressed in Portunus trituberculatus Intestine Functions in AMP Regulation and Prophenoloxidase Activation. Antibiotics (Basel) 2021; 10:antibiotics10050541. [PMID: 34066980 PMCID: PMC8151143 DOI: 10.3390/antibiotics10050541] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/30/2022] Open
Abstract
A C-type lectin (PtCLec2) from Portunus trituberculatus was identified for characterization of its role in defense and innate immunity. PtCLec2 contains a single carbohydrate-recognition domain (CRD) with a conserved QPD motif, which was predicted to have galactose specificity. The mRNA expression of PtCLec2 was predominantly detected in intestine and increased rapidly and significantly upon pathogen challenge. The recombinant PtCLec2 (rPtCLec2) could bind various microorganisms and PAMPs with weak binding ability to yeast and PGN. It agglutinated the tested Gram-negative bacteria (Vibrio alginolyticus and Pseudomonas aeruginosa), Gram-positive bacteria (Staphylococcus aureus and Micrococcus luteus), and rabbit erythrocytes in the presence of exogenous Ca2+, and these agglutination activities were suppressed by LPS, d-galactose, and d-mannose. Further, rPtCLec2 enhanced phagocytosis and clearance of V. alginolyticus, and displayed inhibitory activities against the tested bacteria. Knockdown of PtCLec2 decreased the transcription of two phagocytosis genes (PtArp and PtMyosin), three prophenoloxidase (proPO) system-related genes (PtPPAF, PtcSP1, and PtproPO), six antimicrobial peptides (AMPs) (PtALF4-7, PtCrustin1, and PtCrustin3), and PtRelish but upregulated the expression levels of PtJNK, PtPelle, and PtTLR. These results collectively indicate that PtCLec2 might perform its immune recognition function via binding and agglutination, and mediate pathogen elimination via regulating hemocyte phagocytosis, AMP synthesis, and proPO activation.
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Affiliation(s)
- Yuan Liu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Y.S.); (A.Z.)
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: ; Tel.: +86-532-8289-8637
| | - Yue Su
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Y.S.); (A.Z.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ao Zhang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (Y.S.); (A.Z.)
| | - Zhaoxia Cui
- School of Marine Science, Ningbo University, Ningbo 315211, China;
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Qiu W, Chen F, Chen R, Li S, Zhu X, Xiong M, Wang KJ. A New C-Type Lectin Homolog SpCTL6 Exerting Immunoprotective Effect and Regulatory Role in Mud Crab Scylla paramamosain. Front Immunol 2021; 12:661823. [PMID: 33897708 PMCID: PMC8062930 DOI: 10.3389/fimmu.2021.661823] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/16/2021] [Indexed: 11/15/2022] Open
Abstract
C-type lectin (CTL), a well-known immune-related molecule, has received more and more attention due to its diverse functions, especially its important role in development and host defense of vertebrate and invertebrate. Since the research on crab CTLs is still lack, we screened a new CTL homolog, named SpCTL6 from mud crab Scylla paramamosain. The full-length cDNA sequence of SpCTL6 was 738 bp with a 486 bp of ORF, and the deduced amino acids were 161 aa. SpCTL6 was predicted to have a 17 aa signal peptide and its mature peptide was 144 aa (MW 16.7 kDa) with pI value of 5.22. It had typical CTL structural characteristics, such as a single C-type lectin-like domain, 4 conserved cysteines, similar tertiary structure to that of vertebrate CTLs and a mutated Ca2+ binding motif Gln-Pro-Thr (QPT), clustering into the same branch as the crustacean CTLs. SpCTL6 was highly expressed in the entire zoeal larval stages and widely distributed in adult crab tissues with the highest transcription level in testis. During the molting process of juvenile crabs, the expression level of SpCTL6 was remarkably increased after molting. SpCTL6 could be significantly upregulated in two larval stages (Z1 and megalopa) and adult crab testis under immune challenges. Recombinant SpCTL6 (rSpCTL6) was successfully obtained from eukaryotic expression system. rSpCTL6 exhibited binding activity with PAMPs (LPS, lipoteichoic acid, peptidoglycan, and glucan) and had a broad spectrum bacterial agglutination activity in a Ca2+-dependent manner. In addition, rSpCTL6 could enhance the encapsulation activity of hemocytes and has no cytotoxic effect on hemocytes. Although rSpCTL6 had no bactericidal activity on Vibrio alginolyticus, rSpCTL6 treatment could significantly reduce the bacterial endotoxin level in vitro and greatly improved the survival of S. paramamosain under V. alginolyticus infection in vivo. The immunoprotective effect of rSpCTL6 might be due to the regulatory role of rSpCTL6 in immune-related genes and immunological parameters. Our study provides new information for understanding the immune defense of mud crabs and would facilitate the development of effective strategies for mud crab aquaculture disease control.
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Affiliation(s)
- Wanlei Qiu
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China
| | - Fangyi Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China.,State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China.,Fujian Innovation Research Institute for Marine Biological Antimicrobial Peptide Industrial Technology, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China
| | - Roushi Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China
| | - Shuang Li
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China
| | - Xuewu Zhu
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China
| | - Ming Xiong
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China.,State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China.,Fujian Innovation Research Institute for Marine Biological Antimicrobial Peptide Industrial Technology, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China
| | - Ke-Jian Wang
- State Key Laboratory of Marine Environmental Science, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China.,State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China.,Fujian Innovation Research Institute for Marine Biological Antimicrobial Peptide Industrial Technology, College of Ocean & Earth Sciences, Xiamen University, Xiamen, China
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Huang Y, Jiang F, Wang R, Shi Y, Hu S, Wu T, Zhao Z. In silico characterization and expression analysis of eight C-type lectins in obscure puffer Takifugu obscurus. Vet Immunol Immunopathol 2021; 234:110200. [PMID: 33571917 DOI: 10.1016/j.vetimm.2021.110200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 01/24/2023]
Abstract
C-type lectins (CTLs) are a group of carbohydrate-binding proteins that play crucial roles in innate immune defense against invading pathogens. CTLs have been extensively studied in lower vertebrates, such as fish, for their roles in eliminating pathogens; however, their homologs in pufferfish are not well known. In the present study, eight CTLs from obscure puffer Takifugu obscurus (designated as ToCTL3-10 according to the order they were discovered) were obtained. All predicted ToCTL proteins contained a single carbohydrate recognition domain (CRD). ToCTL7 also contained one calcium-binding epidermal growth factor (EGF)-like domain (EGF_CA) and a transmembrane region. ToCTL9 also contained an SCP domain, an EGF domain, and an EGF-like domain. Bioinformatics analysis revealed that ToCTL3-10 mainly clustered with the corresponding CTL homologs of other pufferfish species. Tissue distribution analysis detected ToCTL3-10 in all tissues examined, including kidneys, liver, gills, spleen, intestines, and heart. Moreover, the expressions of ToCTL3-10 were significantly induced in the kidneys of obscure puffer following challenges with three Gram-negative bacterial pathogens, namely, Vibrio harveyi, Aeromonas hydrophila, and Edwardsiella tarda, and a synthetic analog of double-stranded RNA poly(I:C). The expression patterns of ToCTL3-10 in response to different immune stimulants were different. Our results indicated that the eight ToCTLs obtained herein might be involved in host defense against bacterial and poly(I:C) infections in T. obscurus.
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Affiliation(s)
- Ying Huang
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China; Postdoctoral Innovation Practice Base, Jiangsu Shuixian Industrial Company Limited, 40 Tonghu Road, Baoying, Yangzhou, Jiangsu 225800, China
| | - Fuhui Jiang
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China
| | - Ruixia Wang
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China
| | - Yan Shi
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China
| | - Sufei Hu
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China
| | - Ting Wu
- Postdoctoral Innovation Practice Base, Jiangsu Shuixian Industrial Company Limited, 40 Tonghu Road, Baoying, Yangzhou, Jiangsu 225800, China
| | - Zhe Zhao
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China.
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He J, Shen C, Liang H, Fang X, Lu J. Antimicrobial properties and immune-related gene expression of a C-type lectin isolated from Pinctada fucata martensii. FISH & SHELLFISH IMMUNOLOGY 2020; 105:330-340. [PMID: 32712228 DOI: 10.1016/j.fsi.2020.07.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/01/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
C-type lectins are carbohydrate-binding proteins that play important roles in the innate immune response to pathogen infections. Here, multi-step high performance liquid chromatography (HPLC), combined with mass spectrometry (MS), was used to isolate and identify proteins with antibacterial activity from the serum of Pinctada fucata martensii. Using this method, we obtained a novel isoform of C-type lectin (PmCTL-1). PmCTL-1 strongly inhibited gram-positive bacteria. The complete cDNA sequence of PmCTL-1 was 636 bp in length, and encoded a protein 149 amino acids long, containing a typical carbohydrate recognition domain (CRD). A phylogenetic analysis based on a multiple sequence alignment indicated that PmCTL-1 was highly similar to C-type lectins from other mollusks. Fluorescent quantitative real-time PCR analysis showed that PmCTL-1 mRNA was strongly upregulated in the mantle of healthy P.f. martensii, but was expressed only at low levels in the gill, gonad, hepatopancreas, adductor muscle, and hemocytes. PmCTL-1 expression levels in the mantle and hemocytes increased significantly in response to bacterial stimulation. This study provides a valuable framework for further explorations of innate immunity and the immune response in mollusks.
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Affiliation(s)
- Junjun He
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, Guangdong, PR China; Fisheries College of Guangdong Ocean University, Zhanjiang, Guangdong, PR China
| | - Chenghao Shen
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, Guangdong, PR China; Fisheries College of Guangdong Ocean University, Zhanjiang, Guangdong, PR China
| | - Haiying Liang
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, Guangdong, PR China; Fisheries College of Guangdong Ocean University, Zhanjiang, Guangdong, PR China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, Guangdong, PR China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen, Guangdong, PR China.
| | - Xiaochen Fang
- Fisheries College of Guangdong Ocean University, Zhanjiang, Guangdong, PR China
| | - Jinzhao Lu
- Fisheries College of Guangdong Ocean University, Zhanjiang, Guangdong, PR China
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Liu WC, Zhou SH, Balasubramanian B, Zeng FY, Sun CB, Pang HY. Dietary seaweed (Enteromorpha) polysaccharides improves growth performance involved in regulation of immune responses, intestinal morphology and microbial community in banana shrimp Fenneropenaeus merguiensis. FISH & SHELLFISH IMMUNOLOGY 2020; 104:202-212. [PMID: 32504803 DOI: 10.1016/j.fsi.2020.05.079] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 06/11/2023]
Abstract
The present study was conducted to evaluate the effects of marine polysaccharides from seaweed Enteromorpha on growth performance, immune responses, intestinal morphology and microbial community in the banana shrimp Fenneropenaeus merguiensis. Two thousand and four hundred juvenile shrimps with an average body weight of 2.18 ± 0.06 g were fed for 42 d with diets containing different levels of Enteromorpha polysaccharides (EPS): 0 (control), 1, 2 and 3 g/kg as treatment groups, each of group was replicated three times with two hundred shrimps per replicate. Dietary supplementation of 1 g/kg EPS showed a consistent improvement in the final weight, weight gain, average daily gain rate (ADGR) and specific growth rate (SGR) (P < 0.05), while showed a decrease in the feed conversion ratio (FCR) of shrimp (P < 0.05). Besides, the total anti-oxidative capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), lysozyme (Lyz), alkaline phosphatase (ALP), and phenoloxidase (PO) activities in hemolymph were enhanced by dietary supplementation of 1 g/kg EPS (P < 0.05), while it reduced the hemolymph MDA content (P < 0.05). Shrimp fed 1 g/kg EPS supplemented diets up-regulated FmLyz, FmSOD5 and FmCLAP gene expression level of hepatopancreas and gill (P < 0.05), and also improved the intestinal FmLC2, FmLyz, FmSOD5 and FmCLAP gene expression levels (P < 0.05). In addition, shrimp fed diets containing 1 g/kg EPS increased the villus width (P < 0.05) and resulted in a higher villus surface area (P < 0.05). According to 16S rRNA sequencing results, dietary supplementation of 1 g/kg EPS tended to increase the relative abundance of Firmicutes at phylum level (P = 0.07) and decrease the relative abundance of Vibrio at genus level (P = 0.08). There was a significant positive correlation between the relative abundance of Firmicutes and mRNA expression of intestinal immune-related genes (P < 0.05). These findings revealed that dietary 1 g/kg EPS could improve growth performance, enhance nonspecific immunity and modulate intestinal function of banana shrimp F. merguiensis.
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Affiliation(s)
- Wen-Chao Liu
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, PR China
| | - Shi-Hui Zhou
- College of Fisheries, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, PR China
| | | | - Fu-Yuan Zeng
- College of Fisheries, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, PR China
| | - Cheng-Bo Sun
- College of Fisheries, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, PR China.
| | - Huan-Ying Pang
- College of Fisheries, Guangdong Ocean University, Zhanjiang, Guangdong, 524088, PR China; Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals, Zhanjiang, 524025, China; Guangdong Key Laboratory of Control for Diseases of Aquatic Economic Animals, Zhanjiang, 524025, China.
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Wang XW, Vasta GR, Wang JX. The functional relevance of shrimp C-type lectins in host-pathogen interactions. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 109:103708. [PMID: 32305304 DOI: 10.1016/j.dci.2020.103708] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 04/10/2020] [Accepted: 04/10/2020] [Indexed: 06/11/2023]
Abstract
C-type lectins (CTLs) are key recognition proteins in shrimp immunity. A few years ago we reviewed sequence information, ligand specificity, expression profiles and specific functions of the shrimp CTLs. Since then, multiple integrated studies that implemented biochemical approaches using both the native and recombinant proteins, functional genetic approaches using RNA interference, and mechanistic studies by analyzing protein-protein interactions were carried out. Results from these rigorous studies revealed the functions and mechanisms of action of selected members of the shrimp CTL family. This review focuses on this new knowledge, that includes unique structural aspects, functions, and mechanisms in host-pathogen interactions, the functional relevance of regions other than the C-type lectin domain, and the regulation of transcription of shrimp CTLs. Thus, this review aims to provide a detailed update of recent studies that have contributed to our better understanding of the shrimp immune events that involve CTL functions.
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Affiliation(s)
- Xian-Wei Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, State Key Laboratory of Microbial Technology, Shandong University, Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
| | - Gerardo R Vasta
- Department of Microbiology and Immunology, School of Medicine, University of Maryland Baltimore, Institute of Marine and Environmental Technology, Baltimore, MD, USA
| | - Jin-Xing Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, State Key Laboratory of Microbial Technology, Shandong University, Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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Liang W, Wu R, Yang T, Shen H, Hu Z. Effect of pathogenic bacteria on a novel C-type lectin, hemocyte and superoxide dismutase/ alkaline phosphatase activity in Onchidium reevesii. FISH & SHELLFISH IMMUNOLOGY 2020; 102:185-194. [PMID: 32289514 DOI: 10.1016/j.fsi.2020.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Bacterial infection in the marine environment is a serious problem to maintain the stability of marine ecosystems. Nevertheless, there is little report so far for the biological effects of pathogenic bacteria in coastal ecosystems. Hence, we investigated the responses of shell-less Onchidium reevesii to resist against pathogenic bacterial infection. Analysis of data here could be used as fundamental information for assessment of innate immune response of O. reevesii. The full-length OrCTL cDNA was cloned and consists of 1849 base pair (bp) encoding protein of 192 amino acids. Constructing multiple alignments suggested that OrCTL has conserved carbohydrate recognition domain (CRD) of CTLs, containing an EPS (Glu-Pro-Ser) motif that may imply the function of recognition of carbohydrates like others invertebrate. OrCTL mRNAs were mainly detected in ganglion and hepatopancreas, and expression was highly up-regulated from 2 h after Vibrio harveyi challenge, rapidly decreased at 4 h, and significantly increased at 12 h. In addition, after challenge with Vibrio parahaemolytics, OrCTL gene expression was slightly up-regulated from 2 h, peaked at 12 h. Enzyme activity (in the hepatopancreas) and cell immune (in the hemolymph) were investigated along with Superoxide dismutase (SOD) activity, alkaline phosphatase (ALP) activity and cell cycle. SOD activities were significantly higher after V. harveyi and V. parahaemolytics challenge than that in the control group, respectively. By contrast, ALP activities were significantly inhibited after challenged with bacteria than that in the control group, respectively. Enzyme activities in the hepatopancreas obviously fluctuated, and ALP activity was more sensitive to bacteria. Cell responses illustrated that there were a significant higher percentage of cells in the S and G2/M phase in hemolymph after challenged with bacteria. Our results suggested that the immune response of O. reevesii could be activated by pathogenic bacteria, and the data will provide referent for the disease prevention of systematic investigation in aquatic animal.
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Affiliation(s)
- Wei Liang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, China; National Demonstration Center for Experimental Fisheries Science Education, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Rongyu Wu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, China; National Demonstration Center for Experimental Fisheries Science Education, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Tiezhu Yang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, China; National Demonstration Center for Experimental Fisheries Science Education, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China
| | - Heding Shen
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, China; National Demonstration Center for Experimental Fisheries Science Education, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China.
| | - Zhongjun Hu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, China; National Demonstration Center for Experimental Fisheries Science Education, China; Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Shanghai Ocean University, Shanghai, 201306, China.
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Su Y, Liu Y, Gao F, Cui Z. A novel C-type lectin with a YPD motif from Portunus trituberculatus (PtCLec1) mediating pathogen recognition and opsonization. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 106:103609. [PMID: 31923433 DOI: 10.1016/j.dci.2020.103609] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/30/2019] [Accepted: 01/05/2020] [Indexed: 06/10/2023]
Abstract
C-type lectins are a superfamily of Ca2+-dependent carbohydrate-recognition proteins that function as pattern recognition receptors (PRRs) in innate immune system. In this study, a new C-type lectin was identified from the swimming crab Portunus trituberculatus (PtCLec1). The full-length cDNA of PtCLec1 was 873 bp encoding 176 amino acids. The predicted PtCLec1 protein contained a signal peptide and a single carbohydrate-recognition domain with a special YPD motif. The PtCLec1 transcripts were mainly detected in hepatopancreas and its relative expression levels were significantly up-regulated after the challenges of Vibrio alginolyticus, Micrococcus luteus and Pichia pastoris. The recombinant PtCLec1 (rPtCLec1) could bind all the tested pathogen-associated molecular patterns (PAMPs), including lipopolysaccharides (LPS), peptidoglycan (PGN) and glucan (GLU), and microorganisms, including V. alginolyticus, V. parahaemolyticus, Pseudomonas aeruginosa, Staphylococcus aureus, M. luteus and P. pastoris. It also exhibited strong activity to agglutinate bacteria and yeast in a Ca2+-dependent manner, and such agglutinating activity could be inhibited by d-galactose and LPS. Moreover, rPtCLec1 revealed antimicrobial activity against the tested Gram-negative (V. alginolyticus, V. parahaemolyticus and P. aeruginosa) and Gram-positive bacteria (S. aureus and M. luteus), and promoted the clearance of V. alginolyticus in vivo and hemocyte phagocytosis in vitro. Knockdown of PtCLec1 could down-regulate the expression of phagocytosis-related genes, but enhance the expression levels of prophenoloxidase (proPO) system-related genes, mannose-binding lectin (MBL), antimicrobial peptides (AMPs), MyD88 and Relish. All these results indicate that PtCLec1 might act as a PRR in immune recognition and an opsonin in pathogen elimination.
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Affiliation(s)
- Yue Su
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuan Liu
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China.
| | - Fengtao Gao
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China
| | - Zhaoxia Cui
- School of Marine Science, Ningbo University, Zhejiang, Ningbo, 315211, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China
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Liu X, Li X, Peng M, Wang X, Du X, Meng L, Zhai J, Liu J, Yu H, Zhang Q. A novel C-type lectin from spotted knifejaw, Oplegnathus punctatus possesses antibacterial and anti-inflammatory activity. FISH & SHELLFISH IMMUNOLOGY 2019; 92:11-20. [PMID: 31132464 DOI: 10.1016/j.fsi.2019.05.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
C-type lectin is a type of carbohydrate-binding protein and plays significant roles in innate immune response against pathogen infection. To date, thousands of C-type lectin had been identified in teleost. In the present study, we isolated a novel isoform of C-type lectin (OppCTL) from spotted knifejaw (Oplegnathus punctatus). The OppCTL encoded a typical Ca2+-dependent carbohydrate-binding protein, and was mainly expressed in liver in a tissue specific fashion. The expression of OppCTL was significantly up-regulated following Vibrio anguillarum infection in vivo, suggesting involvement in immune response. Hemagglutination analysis showed that the recombinant OppCTL (rOppCTL) could agglutinate erythrocyte from Mus musculus, Oplegnathus punctatus, Sebastes schlegelii and Paralichthys olivaceus. The rOppCTL could bind and agglutinate all tested bacteria. The rOppCTL possessed capacities of calcium-dependent agglutination to all tested bacteria. Sugar binding assay revealed that rOppCTL could also bind to the glycoconjugates of the bacterial surface, including lipopolysaccharide and peptidoglycan. Interestingly, Dual-luciferase analysis revealed that OppCTL could inhibit the activity of NF-κB in HEK-293T cells after OppCTL overexpression. Taken together, these results indicate that OppCTL has immune activity capable of defending invading pathogens and possesses potential immunoregulatory activity, enriching our understanding of the function of C-type lectin.
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Affiliation(s)
- Xiaobing Liu
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China
| | - Xuemei Li
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China
| | - Meiting Peng
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China
| | - Xuangang Wang
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China
| | - Xinxin Du
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China; Department of Life Science and Engineering, Jining University, Jining, China
| | - Lihui Meng
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China
| | - Jieming Zhai
- LaizhouMingbo Aquatic CO., Ltd., Laizhou, Shandong, China
| | - Jinxiang Liu
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
| | - Haiyang Yu
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
| | - Quanqi Zhang
- Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China.
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Huang Y, Zhang R, Gao T, Xu H, Wu T, Ren Q. 2-Transmembrane C-type lectin from oriental river prawn Macrobrachium nipponense participates in antibacterial immune response. FISH & SHELLFISH IMMUNOLOGY 2019; 91:58-67. [PMID: 31096059 DOI: 10.1016/j.fsi.2019.05.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/07/2019] [Accepted: 05/13/2019] [Indexed: 06/09/2023]
Abstract
As a type of pattern-recognition proteins (PRRs), C-type lectins (CTLs) perform important functions in non-self recognition and clearance of pathogens in innate immunity. In this study, a unique 2-transmembrane CTL (designated as Mn-2TM-cLec) with a single carbohydrate recognition domain (CRD) was isolated from Macrobrachium nipponense. The full-length cDNA of Mn-2TM-cLec consisted of 3265 bp with an 837 bp open reading frame encoding a protein with 278 amino acids. Mn-2TM-cLec was ubiquitously distributed in various tissues of normal prawn, particularly in the hemocytes, hepatopancreas, and gills. The expression of Mn-2TM-cLec was significantly up-regulated in the gills and hepatopancreas after the prawns were challenged with Staphylococcus aureus and Vibrio parahaemolyticus. RNA interference knock-down of Mn-2TM-cLec gene decreased the transcription levels of three antimicrobial peptides (anti-lipopolysaccharide factor (ALF) 1, ALF2, and Crustin (Crus) 1) after V. parahaemolyticus infection. The recombinant CRD of Mn-2TM-cLec could bind lipopolysaccharide, peptidoglycans, and diverse bacterial strains and agglutinate S. aureus and V. parahaemolyticus in a Ca2+-dependent manner. In addition, the rCRD enhanced the clearance of V. parahaemolyticus injected in prawns. In summary, Mn-2TM-cLec might act as a PRR to participate in the prawn immune defense against pathogens through its antimicrobial activity.
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Affiliation(s)
- Ying Huang
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu, 210098, China; Postdoctoral Innovation Practice Base, Jiangsu Shuixian Industrial Company Limited, 40 Tonghu Road, Baoying, Yangzhou, Jiangsu, 225800, China
| | - Ruidong Zhang
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu, 210023, China
| | - Tianheng Gao
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu, 210098, China
| | - Hui Xu
- Nanjing Hydraulic Research Institute, Nanjing, 210024, China
| | - Ting Wu
- Postdoctoral Innovation Practice Base, Jiangsu Shuixian Industrial Company Limited, 40 Tonghu Road, Baoying, Yangzhou, Jiangsu, 225800, China
| | - Qian Ren
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu, 222005, China; College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu, 210023, China.
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Runsaeng P, Kwankaew P, Utarabhand P. FmLC6: An ultimate dual-CRD C-type lectin from Fenneropenaeus merguiensis mediated its roles in shrimp defense immunity towards bacteria and virus. FISH & SHELLFISH IMMUNOLOGY 2018; 80:200-213. [PMID: 29842930 DOI: 10.1016/j.fsi.2018.05.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/18/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
C-type lectins are a member of pattern recognition receptors (PRRs) that can interact with pathogen-associated molecular patterns of invading microorganisms by using their conserved motifs in carbohydrate recognition domain (CRD). The binding can trigger various immune responses in both direct and indirect mechanisms. Hereby, an ultimate C-type lectin with dual CRDs each of which containing a different motif was identified from hepatopancreas of Fenneropenaeus merguiensis (mentioned as FmLC6). The full-length cDNA of FmLC6 consisted of 1148 bp comprising one 1005 bp open reading frame (ORF) encoding a signal peptide and a mature protein of 317 residues. FmLC6 was composed of two CRDs with a highly conserved QPD (Gln-Pro-Asp) motif and one variant EPQ (Glu-Pro-Gln) motif for illustrating the carbohydrate binding affinity. The transcription of FmLC6 was detected only in hepatopancreas of normal shrimp. After injection with pathogens or immunostimulants, the expression of FmLC6 was significantly up-regulated and reached the highest level at 12 h post-injection except with lipoteichoic acid challenge. The FmLC6 expression was severely suppressed by knockdown based-silencing. This gene silencing with co-injection by Vibrio parahaemolyticus caused increasing in cumulative mortality and reduction of the median lethal time. Purified recombinant proteins of an entire ORF and two individual CRDs of FmLC6 produced in Escherichia coli could induce a broad spectrum of microbial agglutination with calcium dependence. The agglutination induced by rFmLC6, rCRD1 and rCRD2 was suppressed by galactose plus mannose, galactose and mannose, respectively which this event was confirmed by the inhibition of hemagglutination. All three recombinant proteins possessed ability to inhibit the bacterial growth with a dose-response. Purified rFmLC6 could bind directly to white spot syndrome virus particles and also its recombinant proteins including VP15, VP39A and VP28 with different affinity. Altogether, these results indicate that FmLC6 acts as a PRR to recognize invading microorganisms and leads to mediating the immune response to cooperation in pathogenic elimination via the binding, agglutination and antimicrobial activity.
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Affiliation(s)
- Phanthipha Runsaeng
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
| | - Pattamaporn Kwankaew
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Prapaporn Utarabhand
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
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Phupet B, Pitakpornpreecha T, Baowubon N, Runsaeng P, Utarabhand P. Lipopolysaccharide- and β-1,3-glucan-binding protein from Litopenaeus vannamei: Purification, cloning and contribution in shrimp defense immunity via phenoloxidase activation. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 81:167-179. [PMID: 29191550 DOI: 10.1016/j.dci.2017.11.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 11/23/2017] [Accepted: 11/24/2017] [Indexed: 06/07/2023]
Abstract
Lipopolysaccharide- and β-1,3-glucan-binding protein (LGBP) existed in diversity of invertebrates including shrimp plays a crucial role in an innate immunity via mediating the recognition of invading pathogens. In this study, LGBP was cloned and characterized from the hepatopancreas of Litopenaeus vannamei, named as LvLGBP. Its full-length cDNA of 1282 bp contained an open reading frame (1101 bp) encoding a peptide of 367 amino acids. The LGBP primary structure contained a glycosyl hydrolase domain, two integrin binding motifs, two kinase C phosphorylation sites, and two polysaccharide recognition motifs which were identified as a polysaccharide binding motif and a β-1,3-glucan recognition motif. The LvLGBP transcripts were expressed mainly in the hepatopancreas. Upon challenge with Vibrio parahaemolyticus or white spot syndrome virus (WSSV), the LvLGBP mRNA expression was significantly up-regulated to reach a maximum at 48 h post injection. Its expression was also induced by lipopolysaccharide (LPS) or β-1,3-glucan stimulation. RNAi-based silencing resulted in the critical suppression of LvLGBP expression. Knockdown of LvLGBP gene with co-inoculation by V. parahaemolyticus or WSSV led to increase in the cumulative mortality and reduce in the median lethal time. Native LGBP was detected only in the hepatopancreas as verified by Western blotting. Purified LGBP from the hepatopancreas exhibited the agglutinating and binding activity towards Gram-negative bacterium V. parahaemolyticus with calcium-dependence. Its agglutinating activity was dominantly inhibited by LPS with higher potential than β-1,3-glucan. Purified LvLGBP could significantly activate the hemocyte phenoloxidase activity in the presence of LPS (12.9 folds), while slight activation was detected with β-1,3-glucan (2.0 folds). It could enhance the encapsulation by hemocytes but did not have antibacterial activity. These results provided evidence that LvLGBP might act as a pathogenic recognition protein to activate shrimp immune defense against invading pathogens via the agglutination, binding and enhancing encapsulation and phenoloxidase activity of the hemocytes.
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Affiliation(s)
- Benjaporn Phupet
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Thanawat Pitakpornpreecha
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Nuntaporn Baowubon
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Phanthipha Runsaeng
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Prapaporn Utarabhand
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
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Kwankaew P, Praparatana R, Runsaeng P, Utarabhand P. An alternative function of C-type lectin comprising low-density lipoprotein receptor domain from Fenneropenaeus merguiensis to act as a binding receptor for viral protein and vitellogenin. FISH & SHELLFISH IMMUNOLOGY 2018; 74:295-308. [PMID: 29289654 DOI: 10.1016/j.fsi.2017.12.044] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/17/2017] [Accepted: 12/22/2017] [Indexed: 06/07/2023]
Abstract
A diversity of C-type lectins (CTLs) was coming reported and they are known to participate in invertebrate innate immunity by act as pattern recognition receptor (PRR). In the present study, a unique CTL containing low-density lipoprotein receptor (LDLR) domain from Fenneropenaeus merguiensis (designated as FmLdlr) was cloned. Its sequence contained a single LDLR domain and one carbohydrate recognition domain (CRD) with a QAP motif putative for galactose-specific binding. The expression of FmLdlr was detected only in hemocytes of healthy shrimp. Its expression was significantly up-regulated by Vibrio parahaemolyticus or white spot syndrome virus (WSSV) challenge. The knockdown by FmLdlr dsRNA resulted in severe gene down-regulation. The gene silencing with pathogenic co-inoculation led to reduction of the median lethal time and increasing in the cumulative mortality including the remained WSSV in WSSV co-challenge group. Recombinant proteins of FmLdlr and two domains could agglutinate various bacterial strains which LDLR domain revealed the lowest activity. Only FmLdlr and CRD could enhance phagocytosis and encapsulation by hemocytes. Both FmLdlr and CRD except LDLR domain exhibited the antibacterial activity by inhibiting the growth of pathogenic V. parahaemolyticus in cultured medium and disk diffusion assay. Only FmLdlr and CRD could bind to WSSV proteins, envelope VP28, tegument VP39A and also capsid VP15, which FmLdlr had the higher binding affinity than that of CRD. Altogether, we concluded that FmLdlr contributed in shrimp immune defense through the main action of CRD in capable of bacterial agglutination, enhancing the phagocytosis and encapsulation, antimicrobial activity and binding to viral proteins. Interestingly, ELISA approach revealed that LDLR domain displayed the highest binding affinity to vitellogenin than whole molecule and CRD. We signified a new function of FmLdlr that it might presumably act as a receptor for vitellogenin transportation in hemolymph during vitellogenesis of shrimp.
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Affiliation(s)
- Pattamaporn Kwankaew
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Rachanida Praparatana
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Phanthipha Runsaeng
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Prapaporn Utarabhand
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
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Senghoi W, Runsaeng P, Utarabhand P. FmLC5, a putative galactose-binding C-type lectin with two QPD motifs from the hemocytes of Fenneropenaeus merguiensis participates in shrimp immune defense. J Invertebr Pathol 2017; 150:136-144. [DOI: 10.1016/j.jip.2017.09.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/16/2017] [Accepted: 09/24/2017] [Indexed: 11/24/2022]
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Runsaeng P, Puengyam P, Utarabhand P. A mannose-specific C-type lectin from Fenneropenaeus merguiensis exhibited antimicrobial activity to mediate shrimp innate immunity. Mol Immunol 2017; 92:87-98. [PMID: 29055189 DOI: 10.1016/j.molimm.2017.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 10/03/2017] [Accepted: 10/09/2017] [Indexed: 10/18/2022]
Abstract
Being one type of pattern recognition receptors (PRRs), lectins exhibit a crucial role in the defense mechanism of invertebrates which are deficient in an adaptive immune system. A new C-type lectin called FmLC3 was isolated from hepatopancreas of Fenneropenaeus merguiensis by cloning approaches, RT-PCR and 5' and 3' RACE (rapid amplification of cDNA ends). A full-length cDNA of FmLC3 contains 607 bp with one open reading frame of 480bp, encoding a 159-amino acids peptide. The predicted primary structure of FmLC3 is composed of a signal peptide, a carbohydrate recognition domain with an EPN motif and one Ca2+ binding site-2, including a double-loop region assisted by two conserved disulfide linkages. FmLC3 had a molecular mass of 17.96kDa and pI of 4.92. In normal or unchallenged shrimp, the mRNA expression of FmLC3 was detected only in hepatopancreas whilst its native proteins were found in hemolymph, heart, stomach and intestine but not in the expressed tissue, indicating that after being synthesized in hepatopancreas, FmLC3 would be secreted to other tissues. The significant up-regulation of FmLC3 was manifested in shrimp challenged with Vibrio harveyi or white spot syndrome virus. After knockdown with gene-specific double-stranded RNA and following by co-pathogenic inoculation, the FmLC3 expression was severely suppressed with coherence of increasing in cumulative mortality and reduction of the median lethal time. Recombinant FmLC3 (rFmLC3) had agglutinating activity towards diverse bacterial strains in a Ca2+-dependent manner. Its activity was inhibited by lipopolysaccharide and mannose, implying that FmLC3 was mannose-binding C-type lectin. Moreover, rFmLC3 could bind directly to various microbial strains with Ca2+-requirement. Otherwise, rFmLC3 exhibited the antimicrobial activity by inhibiting effectively the microbial growth in vitro. All these results signified that FmLC3 might act as PRR to recognize with a broad specificity for diverse pathogens, and contribute in shrimp immune response via the agglutination, binding and antimicrobial activity.
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Affiliation(s)
- Phanthipha Runsaeng
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Peerapong Puengyam
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Prapaporn Utarabhand
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
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