Structural characterization and immunostimulatory activity of a water-soluble polysaccharide from abalone(Haliotis discus hannai Ino)muscle

A water-soluble polysaccharide from abalone muscle(AMPP)was isolated.The contents of carbohydrate,protein,uronic acid,and sulfate in AMPP were 83.5%,0.5%,2.7%,and 2.6%,respectively.High-performance liquid chromatography analysis indicated that AMPP was homogeneous and had an average molecular weight of approximately 3.2 kDa.The main monosaccharides of AMPP were glucose(Glc)and mannose with a molar ratio of 99.7:0.3.The structural characteristics of AMPP were elucidated through methylation analysis,Fourier transform infrared spectroscopy,and nuclear magnetic resonance spectroscopy.The linkages of AMPP consisted of terminal,1,4-linked,1,6-linked,and 1,4,6-linked Glcp with a molar ratio of 3.1:7.2:1.0:2.5.In one repeat unit of the proposed AMPP structure,the backbone chain was composed of eight 1→4 glycosidic bonds and one 1→6 glycosidic bond,with three branch chains linked by 1→6 glycosidic bond.In addition,AMPP was found to possess potent immunostimulatory activity via rising phagocytosis of RAW264.7 cells and promoting secretion of TNF-α.

Time-resolved and multi-tissue RNAseq provides new insights on the immune responses of European eels following infection with Aeromonas hydrophila

No studies have systematically compared time-resolved and multi-tissue innate immune responses for European eels(Anguilla anguilla)with Aeromonas hydrophila infection by a high throughput method.Here,we challenged European eels with A.hydrophila(infected)or PBS(control).A low fatality rate(16.1%)was observed for the infected group at 2 d post-infection(dpi).Then we examined transcriptional profiles of intestines,livers and spleens from 12 European eels with/without infection by A.hydrophila at 6,18 and 36 h post-infection(hpi).The results showed that the most differentially expressed genes(DEGs)were found in the spleen at 6 hpi(7569 DEGs),followed by the intestine at 6 hpi(3129 DEGs)and the liver at 18 hpi(2722 DEGs).Only 540,41 and 130 DEGs were found in the spleen,liver,and intestine at 36 hpi,respectively.The comparison of DEG numbers and enriched KEGG pathways suggested a consistent time-course immune response in these tissues.A similar enrichment of pattern recognition receptors-related pathways including Toll-like receptors,NOD-like receptors and RIG-I-like receptors was found in the liver and spleen,but not in the intestine.Among immune-related DEGs,62 paralogue pairs were found,and the expression trends of most paralogues were consistent.Some paralogues of immune-related DEGs had unique domains.Furthermore,large clusters representing similar tissue were shown for the intestine and spleen.A different co-expression network involved in cytokine signal transduction and interaction existed between the liver and spleen.This study has provided time-resolved and multi-tissue transcriptome characteristics of A.anguilla in response to A.hydrophila infection.

Efficient gene editing in a medaka(Oryzias latipes)cell line and embryos by SpCas9/tRNA-gRNA

Generation of mutants with clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)is commonly carried out in fish species by co-injecting a mixture of Cas9 messenger RNA(mRNA)or protein and transcribed guide RNA(gRNA).However,the appropriate expression system to produce functional gRNAs in fish embryos and cells is rarely present.In this study,we employed a poly-transfer RNA(tRNA)-gRNA(PTG)system driven by cytomegalovirus(CMV)promoter to target the medaka(Oryzias latipes)endogenous gene tyrosinase(tyr)or paired box 6.1(pax6.1)and illustrated its function in a medaka cell line and embryos.The PTG system was combined with the CRISPR/Cas9 system under high levels of promoter to successfully induce gene editing in medaka.This is a valuable step forward in potential application of the CRISPR/Cas9 system in medaka and other teleosts.