Gregorykudsk9824

The programmed cell death protein 4 (PDCD4) is a newly defined transcriptional and translational inhibitor, which plays a key role in regulating the synthesis of inflammatory cytokines in vertebrates species. In the present study, the full-length cDNA of PDCD4 from oyster Crassostrea gigas (designed as CgPDCD4) was identified to explore its possible involvement in immune response. The open reading frame of pdcd4 gene was of 1344 bp encoding a polypeptide of 447 amino acids with two conserved MA-3 domains. selleck inhibitor The deduced amino acid sequence of CgPDCD4 shared 60.18% similarity with PDCD4 from Mizuhopecten yessoensis. The mRNA transcripts of CgPDCD4 could be detected in all the tested tissues with a higher expression level in adductor muscle and hemocytes. The mRNA expression of CgPDCD4 in hemocytes was significantly down-regulated at 3 h and 6 h (0.61-fold and 0.42-fold of that in PBS group, p  less then  0.01, respectively) after LPS stimulation. In hemocytes, CgPDCD4 protein was found to be mainly located in the cytoplasm. After the mRNA expression of CgPDCD4 in hemocytes was knocked down (0.40-fold of that in EGFP-RNAi group) by CgPDCD4 dsRNA (dsCgPDCD4) injection, the CgIL17-5 transcripts were up-regulated (20.11-fold of that in PBS group, p  less then  0.01) post LPS stimulation, which was significantly higher than that in dsEGFP-injected oysters (7.06-fold of that in PBS group, p  less then  0.01). Meanwhile, the nuclear translocation of CgRel (homologue of Rel/NF-κB) was significantly enhanced (about 1.36-fold of that in PBS group, p  less then  0.01), but it was similar as that in EGFP-RNAi group (about 1.52-fold of that in PBS group, p  less then  0.01) after LPS stimulation. All the results suggested that CgPDCD4 in oysters played the same role as PDCD4 of vertebrates in negatively regulating the production of interleukin in immune response, but the underpinning signal pathway was not conserved during evolution. Cecropin AD (CAD) is a commercial cationic antimicrobial peptide that has been seldom studied in marine fish. This study investigated the effects of dietary CAD on intestinal health, immune response, disease resistance, and growth performance of turbot. A diet using fishmeal and plant protein as the main protein resources was used as the control (crude protein 53%, crude lipid 12%). CAD was supplemented into the control diet at the level of 250, 500, 750, and 1000 mg kg-1 to formulate four experimental diets, C1, C2, C3, and C4, respectively. No significant difference was observed in fish growth performance, feed utilization efficiency and whole-body composition among all groups. Dietary CAD significantly increased the activity of lysozyme and complement component 3 level in both serum and distal intestine (DI), as well as the immunoglobulin M content in DI. The gene expression of immune cytokines such as IFN-γ, IL-1β, and chemokine SmCCL19, and the goblet cell number in DI were also significantly increased by dietary CAD supplementation. Compared with the control group, the microbiota analysis indicated group C4 showed significantly decreased α-diversity, obvious alternation in dominant bacteria composition at phylum level, different clustering, and significantly decreased relative abundance of Lactobacillus. Besides, the relative abundance of Bacteroides was significantly decreased in groups C1, C3, and C4. In addition, the lowest mortality of turbot challenged with Edwardsiella tarda was observed in fish fed diets C2 and C3. In conclusion, moderate levels of CAD in diet of turbot improved the intestinal immune response without disrupting the intestinal bacterial community, and enhanced the disease resistance. However, dietary CAD at 1000 mg kg-1 greatly affected the intestinal bacterial composition and showed potentially inhibitory effects towards Lactobacillus. Supplying immunostimulants to aquatic feed has been an effective way to enhance the health of aquatic animals and substitute for antibiotics. In the present study, the potential effects of Astragalus polysaccharides (APS) were evaluated in turbot, Scophthalmus maximus. Two levels of APS (50 and 150 mg/kg) were added to the basal diet (CON) and a 63-day growth trial (initial weight 10.13 ± 0.04 g) was conducted. As the results showed, significant improvement on growth performance in the APS groups were observed. In addition, dietary 150 mg/kg APS significantly increased the total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-PX) and lysozyme activities in liver. Meanwhile, APS diets induced the mRNA expression of toll-like receptors (TLRs) such as tlr5α, tlr5β, tlr8 and tlr21, while reduced the expression of tlr3 and tlr22. The expression of inflammatory genes myeloid differentiation factor 88 and nuclear factor kappa b p65 and pro-inflammatory cytokines tumor necrosis factor-α and interleukin-1β were up-regulated in APS groups while the expression of anti-inflammatory cytokine transforming growth factor beta was inhibited. Taken together, the present study indicated that Astragalus polysaccharides could remarkably enhance the growth performance, antioxidant activity and maintain an active immune response in turbot. Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1), a kind of protein tyrosine phosphatases (PTPs), is a critical regulator of antigen receptor signal transduction. Signal transduction of BCR is regulated by phosphatases in teleost as in mammals. In this study, SHP1 from Nile tilapia (Oreochromis niloticus) (OnSHP1) was identified and characterized, including the expression pattern against bacterial infection and regulation function in BCR signaling pathway. The open reading frame of OnSHP1 contains 1749 bp of nucleotide sequence, encoding a protein of 582 amino acids. The OnSHP1 protein was highly conversed compared to that of other species, including two amino-terminal SH2 domains at the N terminus and a PTP catalytic domain. Transcriptional expression analysis revealed that OnSHP1 was detected in all examined tissues and highly expressed in spleen. The up-regulated OnSHP1 expression was observed in peripheral blood, spleen and anterior kidney following challenge with Streptococcus agalactiae or lipopolysaccharide (LPS) in vivo, as well as that displayed in leukocytes stimulated with S.