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The interferon stimulated gene 15 (ISG15) is strongly induced in many cell types by double-stranded RNA (polyinosinic: polycytidylic acid, poly I:C) and viral infection. In this study, we described the nucleotide, mRNA tissue distribution and regulation of an ISG15 gene from turbot, Scophthalmus maximus (SmISG15). SmISG15 gene is 862 bp in length, composed of two exons and one intron, and encodes 158 amino acids. The deduced protein exhibits the highest homology (44.7-71.2% identity) with ISG15s from other fishes and possesses two conserved tandem ubiquitin-like (UBL) domains and a C-terminal RLRGG conjugating motif known to be important for the functions of ISG15s in vertebrates. Phylogenetic analysis grouped SmISG15 into fish ISG15. SmISG15 mRNA was constitutively expressed in all tissues examined, with higher levels observed in immune organs. Gene expression analysis was performed for SmISG15 in the spleen, head kidney, gills and muscle of turbots challenged with poly I:C or turbot reddish body iridovirus (TRBIV) over a 7-day time course. The result showed that SmISG15 was upregulated by both stimuli in all four tissues, with induction by poly I:C apparently stronger and initiated more quickly. A two-wave induced expression of SmISG15 was seen in the spleen, head kidney and gills, suggesting an induction of SmISG15 either by IFN-dependent or -independent pathway. These results provide insights into the roles of fish ISG15 in antiviral immunity.

Constructing accurate constitutive equation from the optimal material constants is the basis for finite element numerical simulation. To accurately describe the creep ageing behavior of 2A12 aluminum alloy, the present work is tentatively to construct an elastic-plastic constitutive model for simulation based on the ANSYS environment. A time hardening model including two stages of primary and steady-state is physically derived firstly, and then determined by electronic creep tensile tests. The material constants within the creep constitutive equations are obtained. Furthermore, to verify the feasibility of the material model, the ANSYS based numerical scheme is established to simulate the creep tensile process by using the proposed material model. Results show that the creep constitutive equation can better describe the deformation characteristics of materials, and the numerical simulations and experimental test points are in good agreement.

Toll-like receptor 22 (TLR22) exists exclusively in aquatic animals and recognizes double stranded RNA (dsRNA). In the present study, a tlr22 gene and its 5'-flanking sequence were cloned from turbot, Scophthalmus maximus, its immune responsive expression was subsequently studied in vivo. The turbot (sm)tlr22 gene spans over 5.6 kb with a structure of 4 exon-3 intron and encodes 962 amino acids. The deduced protein shows the highest sequence identity (76.7%) to Japanese flounder Tlr22 and possesses a signal peptide sequence, a leucine-rich repeat (LRR) domain composed of 27 LRR motifs, a transmembrane region and a Toll/interleukin-1 receptor (TIR) domain. Phylogenetic analysis grouped it with other teleost Tlr22s. The interferon-stimulated response element (ISRE) and signal transducer and activator of transcription (STAT) binding site important for the basal transcriptional activity of TLR3 were predicted in the 5'-flanking sequence of smtlr22 gene. Quantitative real-time PCR (qPCR) analysis demonstrated the constitutive expression of smtlr22 mRNA in all examined tissues with higher levels in the head kidney, kidney and spleen. Further, smtlr22 expression was significantly up-regulated following challenge with polyinosinic: polycytidylic acid (poly I:C), lipopolysaccharide (LPS) or turbot reddish body iridovirus (TRBIV) in the gills, head kidney, spleen and muscle, with maximum increases ranging from 2.56 to 6.24 fold upon different immunostimulants and organs. These findings suggest a possible role of Smtlr22 in the immune responses to the infections of a broad range of pathogens that include DNA and RNA viruses and Gram-negative bacteria.