题目: Expression of Allograft inflammatory factor-1 (AIF-1) in response to bacterial challenge and tissue injury in the pearl oyster, Pinctada martensii 

作者: Jun Li, Jinhui Chen, Yang Zhang, Ziniu Yu*

刊物: Fish & Shellfish Immunology,（IF=2.964，I区）

刊号: 2013,34:365-371 

摘要: Allograft inflammatory factor-1 (AIF-1), an interferon (IFN)-γ-inducible calcium-binding cytokine, is associated with theinflammatory response and defense. We cloned and analyzed the expression pattern of the AIF-1 gene of the pearl oysterPinctada martensii, hereafter designated PmAIF-1. The full-length PmAIF-1 cDNA is 946 bp in length and consists of a 5'-untranslated region (UTR) of 120 bp, a 3'-UTR of 376 bp, and an open reading frame (ORF) of 450 bp encoding a polypeptide of 149 amino acids with an estimated molecular mass of 17 kDa. Sequence analysis reveals that PmAIF-1 contains two EF hand Ca(+2)-binding motifs like those in previously characterized AIF-1s while alignment with known AIF-1 protein sequences reveals higher similarity to invertebrate orthologs than to those of vertebrates. Quantitative PCR analysis reveals that PmAIF-1 is constitutively expressed, with the highest expression detected in hemocytes, and the expression level of PmAIF-1 mRNA was significantly up-regulated in hemocytes, gill, digestive gland under bacterial challenge and tissue injury. After challenged by gram-negative bacteria Vibrio alginolyticus and Vibrio parahaemolyticus, gram-positive bacteria Bacillus subtilis, the expression level of this gene in hemocytes were all up-regulated and reached the maximum point at 12h (5.80 folds, P<0.01), 6h (5.02 folds, P<0.01) and 12h (5.49 folds, P<0.01), respectively. Under shell damage and mantle injury, PmAIF-1 mRNA increased gradually in the first 3h and reached a peak of expression at 6h post-injury. These findings suggest that PmAIF-1 is an acute-response protein involved in the innate immune responses of pearl oysters, and provide general information about the mechanisms of innate immune defense against bacterial infection in pearl oysters. 

题目: The first evidence of positive selection in peptidoglycan recognition protein (PGRP) genes of Crassostrea gigas. 

作者: Zhang Yang, Ziniu Yu*

刊物: Fish & Shellfish Immunology,（IF=2.964，I区）

刊号: 2013,34:1352-1355. 

摘要: The oyster Crassostrea gigas is thought to have developed effective immunity to potentially harmful pathogens while under continuous exposure to marine microorganisms; however, the evolutionary mechanisms by which such immunity developed has not been understood. To understand the evolution of immunity, we characterized the family of peptidoglycan recognitionproteins in the oyster (CgPGRPs). These proteins are crucial pattern recognition receptors for peptidoglycans (PGNs) and thereby, for activating the innate immune response of host. Herein, we identify seven new CgPGRP genes. Phylogenetic analysis of the seven new and five previously reported CgPRGP genes reveals that the CgPRGP gene family can be clustered into two groups, CgPRGPS and CgPRGPL. Moreover, the CgPRGPS group can be further divided into five subgroups. A codon-substitution model and three likelihood ratio tests (LRTs) suggest that seven sites in the CgPGRP family of genes have been subjected to strong positive selection (ω = 3.035-4.143), Three dimensional modeling revealed that these sites are found primarily at the periphery of coils and α-helices rather than in β-strands, perhaps allowing PGRP to adapt to, and recognize, variability of PGN structure. In conclusion, our studies provide the first evidence of positive Darwinianselection in the CgPGRP family, contributing to a better understanding of the adaptive mechanism of host-pathogens interaction in marine mollusks. 

题目: Allograft inflammatory factor-1 stimulates hemocyte immune activation by enhancing phagocytosis and expression of inflammatory cytokines in Crassostrea gigas. 

作者: Yang Zhang, Jun Li, Feng yu, Xiaocui He, Ziniu Yu* 

刊物: Fish & Shellfish Immunology,（IF=2.964，I区）

刊号: 2013,34:1071-1077 

摘要: Allograft inflammatory factor-1 (AIF-1) is a calcium-binding cytokine associated with immune cell activation and inflammatoryresponse. Presently, we have identified and characterized an AIF-1 in a marine bivalve mollusk, Crassostrea gigas, and designated it as CgAIF-1. The full-length CgAIF-1 cDNA is 794 bp, encoding a protein of 149 amino acids with two conserved EF hand Ca(2+)-binding motifs. CgAIF-1 is constitutively expressed in various tissues with enriched expression in hemocytes. Moreover, CgAIF-1 transcription is induced by multiple Pathogen-Associated Molecular Patterns (PAMPs), including poly (I: C), LPS, PGN, HKLM and HKVA, but is limited by 1,3-β-glucan. Furthermore, recombinant CgAIF-1 can specifically stimulate phagocytic ability of granulocytes, but not of intermediate cells and hyalinocytes. CgAIF-1 also enhances mRNA levels of MIF, TNF and IL-17. These results provide the first functional evidence that CgAIF-1 is involved inhemocyte activation in C. gigas, revealing conserved functions of AIF-1 in host defense from mollusks to mammals. 

题目: High mobility group box 1 can enhance NF-κb activation and act as a pro-inflammatory molecule in the Pacific oyster, Crassostrea gigas. 

作者: Jun Li, Yang Zhang, Zhimin Xiang, Shu Xiao, Feng Yu, Ziniu Yu*

刊物: Fish & Shellfish Immunology,（IF=2.964，I区）

刊号: 2013,35:63-70 

摘要: High-mobility group box 1 (HMGB1), a highly conserved DNA-binding protein, is involved in nucleosome formation and transcriptional regulation, and can also act as an extracellular cytokine to trigger inflammation and immune responses. In this study, we identified a HMGB1 gene (hereafter designated as CgHMGB1) in the Pacific oyster Crassostrea gigas. The full-length CgHMGB1 cDNA is 833 bp including 5' and 3'-untranslated regions (UTRs) of 145 and 79 bp, respectively, and an open reading frame (ORF) of 609 bp. The gene encodes a 202 amino acid polypeptide with an estimated molecular mass of 23.3 kDa. Sequence alignment shows that CgHMGB1 contains two basic HMG boxes and a highly acidic C-terminal domain. Recombinant CgHMGB1 proteins can enhance the mRNA level of various inflammatory cytokines in vivo. Typically, CgHMGB1 is localized in the nucleus, though lipopolysaccharide can induce its release to cytoplasm. Moreover, luciferase reporter assays reveal that CgHMGB1 cannot stimulate Nuclear Factor-κB reporter activity alone, but it can enhance Rel-dependent NF-κB activation in a dose-dependent manner. CgHMGB1 is highly expressed in hemocytes and its transcripts are significantly more abundant following bacterial challenge. Our results suggest that CgHMGB1 plays an essential role in innate defense by enhancing Rel-activated NF-κB activity and inducing the expression of inflammatory cytokines. 

题目: Cloning, characterization and expression analysis of a caspase-8 like gene from the Hong Kong oyster, Crassostrea hongkongensis.  

作者: Zhiming Xiang, Fufa Qu, Lin Qi, Yang Zhang, Ying Tong, Ziniu Yu* 

刊物: Fish & Shellfish Immunology,（IF=2.964，I区）

刊号: 2013,36:1797-1803. 

摘要: Apoptosis plays a key role in many biological processes, including homeostasis within the immune system. A family of cysteine proteases, the caspases, constitutes the core of the apoptotic machinery. We have characterized the first bivalvecaspase-8 ortholog from the Hong Kong oyster Crassostrea hongkongensis (designated ChCaspase-8). The full-length cDNA is 1945 bp in length encoding a putative protein of 557 amino acids that contains two N-terminal DED domains, and a CASc domain at the C-terminus. ChCaspase-8 is ubiquitously expressed in oysters, with highest expression levels in the gonad and labial palps. Following microbial infection, the expression of ChCaspase-8 increased in hemocytes from 12 to 72 h post-challenge. When expressed in HeLa cells, ChCaspase-8 is located in the cytoplasm, while over-expression of ChCaspase-8 in HEK293T cells activates the transcriptional activities of NF-κB. These results indicate that ChCaspase-8 might play an important role in the immune and apoptotic responses of oysters.