Abstract:Influenza B virus (IBV) is a segmented negative-strand RNA virus, which often causes local outbreak or seasonal epidemic along with influenza A virus (IAV) in the world. It is pathogenic to children, teenagers and elderly people and has a higher mortality rate in children and adolescents, so it poses a serious threat to public health and health. IBV is more likely to cause complications than IAV and the disease burden of IBV even exceeds IAV in the epidemic season. Recently, especially after winter of 2017, IBV has become the dominant strain in many areas of our country and seriously affects people’s health. In view of this, this article reviews the structure, epidemiology, immunology and prevention of IBV, aiming at enhancing public’s perceptions of the virus and providing reference for making strategies for prevention and control of influenza B.

Abstract:Due to potent bactericidal activity and low rate of drug-resistance, daptomycin is recognized as first line antibiotic to treat serious infections caused by drug-resistant Gram-positive pathogens. However, the incidence of daptomycin resistance is increasing due to its widespread application. Alteration of cell wall homeostasis and membrane phospholipid metabolism is involved in daptomycin resistance. The unique mode of action underlying daptomycin resistance in important pathogens, including Staphylococcus aureus and Enterococci, is presented in this paper.

Abstract:We evaluated the tolerance and pathogenesis of foodborne pathogens with a simulated gastro-intestinal tract model that simulates the chemical, physical and biological effects of human digestion process under laboratory conditions. This could be used to study the tolerance, pathogenesis, gut microbiota interaction and vaccine development of foodborne pathogens, so as to contribute to control and treatment of foodborne pathogens. This review introduces the applications of simulated gastro-intestinal tract model tp evaluate foodborne pathogens, which includes in-vitro static gastro-intestinal model, in-vitro dynamic gastro-intestinal model, conventional animal model and humanized animal model. And the concepts and characteristics of all models are described in detail. Also, the shortcomings of existing models are analyzed, and improvements of artificial gastro-intestinal tract model are prospected. In conclusion, this review could provide comprehensive data for promoting the progress of studying tolerance and pathogenesis of foodborne pathogens.

Abstract:Haplotype is the combination of a series of genetic mutations that coexist on a single chromosome, each of which has its own unique haplotypes. As a common data analysis method, the analysis of haplotype is effective for the localization of heterozygosis SNPs on single chromosome, the excavation of disease genes and the search of maladies treatments. It mainly includes indirect computational inferential method and direct experimental method. In this review we introduced various haplotype analysis methods and applications, especially two important ones: single-molecule dilution and contiguity-preserving transposition sequencing common technology. Meanwhile, further research prospects on haplotype sequencing were proposed.

Abstract:Santalene and santalol are the main components of valuable perfume sandalwood essential oil, and have good antibacterial, anti-oxidation and anti-tumor activities. Commercial sandalwood essential oil is mainly extracted from sandalwood tree that grows slowly and is difficult to cultivate. In addition, the extraction recovery of sandalwood essential oil from sandalwood tree is too low to meet the market demand. These factors make sandalwood essential oil expensive. An option is to use genetic engineering and molecular biological methods to heterologously express related synthase of santalene and santalol in microbial host. In this paper, the biosynthesis progress of santalene and santalol synthase, as well as the optimization of mevalonate metabolic pathways in the hosts are summarized. Furthermore, the strategies of applying protein engineering technology to carry out orthomutation of santalene synthase were also discussed, to provide reference for the optimal biosynthesis of santalene and santalol.

Abstract:As secreted protein and membrane-bound proteins, netrins play important roles in biological processes such as neural cell migration, differentiation and apoptosis. Netrins were thought to guide axon outgrowth and central nervous system morphology since they were discovered. Besides, they also participate in physiological processes such as cell adhesion, migration, differentiation, angiogenesis, lymph angiogenesis, and inflammation in non-neural tissues. Recent studies showed that netrins also involved in the regulation of initiation and development of various tumors including colorectal cancer, pancreatic ductal adenocarcinoma. Because of the functional diversity of netrins and the different biological effects of different receptors in tumor tissue, the specific mechanism of their action in tumors remains unclear. Based on current research progress of our group, this review summed up recent research findings on netrins in relation to cancer biology, suggested possible mechanisms, and discussed the implications in cancer research and intervention.

Abstract:Recombinant PRRSV △2ORF5 gene was constructed using DNA shuffling from four genetically different strains of PRRSV to study its heterologous cross-neutralizing ability. The △2ORF5 mutant gene was cloned into the vector pET-32a and transferred into E. coli BL21. SDS-PAGE confirmed that the molecular weight of the recombinant △2ORF5 was about 42?kDa, consistent with the predicted result. Then the purified recombinant protein was injected into BALB/c mouse to obtain polyclonal antibody. Western blotting analysis with mouse-anti-△2ORF5 polyclonal serum indicated that the parental virus recombinant GP5 protein reacted with the specific antibodies. Four parental viruses could be inhibited by the anti-△2ORF5 polyclonal antibody and the inhibition rates were higher than 53%. This work has laid a foundation for further development vaccine for PRRSV.

Abstract:Racemases have been applied for the synthesis of enantiomerically pure compounds through the deracemization methods. Mandelate racemase from Pseudomonas putida was the only enzyme that catalyzes the interconversion of mandelate enantiomers. Using genome mining approaches, we identified 9 mandelate racemases (MRs). A novel racemase named ArMR with higher activity and better soluble protein expression, was isolated from Agrobacterium radiobacter. ArMR displayed the optimum catalytic activity at 50 ℃, pH 7.8 in Tris-HCl buffer. The half-life of ArMR at 50, 40 and 30 ℃ was 0.17, 27.2 and 70.7 h, respectively. KM parameter of ArMR towards (R)- and (S)-mandelic acid was 1.44 and 0.81 mmol/L, respectively; the corresponding kcat value was 410 s–1 and 218 s–1. In addition, KM of ArMR towards (R)- and (S)-2-chloro mandelic acid was 6.48 and 6.37 mmol/L, and the corresponding kcat value 0.22 s–1 and 0.23 s–1, respectively. Meanwhile, Mg2+ and Mn2+ could activate the enzyme whereas Zn2+ inactivated the enzyme completely. Discovery of more novel MRs provides supports further research and development of these racemases.

Abstract:By-products released from pretreatment process of lignocellulose seriously hinder the development of cellulosic fuel ethanol. Therefore, the great way to increase the efficiency of cellulosic ethanol production is improvement of Saccharomyces cerevisiae tolerance to these inhibitors. In this work, the effects of LCB4 gene overexpression on cell growth and ethanol fermentation in S. cerevisiae S288C under acetic acid, furfural and vanillin stresses were studied. Compared to the control strain S288C-HO, the recombinant strain S288C-LCB4 grew better on YPD solid medium containing 10 g/L acetic acid, 1.5 g/L furfural and 1 g/L vanillin. Ethanol yields of recombinant strain S288C-LCB4 were 0.85 g/(L·h), 0.76 g/(L·h) and 1.12 g/(L·h) when 10 g/L acetic acid, 3 g/L furfural and 2 g/L vanillin were supplemented into the fermentation medium respectively, which increased by 34.9%, 85.4% and 330.8% than the control strain S288C-HO. Meanwhile, ethanol fermentation time was reduced by 30 h and 44 h under furfural and vanillin stresses respectively. Further metabolites analysis in fermentation broth showed that the recombinant strain produced more protective compounds, such as glycerol, trehalose and succinic acid, than the control strain, which could be the reason for enhancing strain tolerance to these inhibitors from pretreatment process of lignocellulose. The results indicated that overexpression of LCB4 gene could significantly improve ethanol fermentation in S. cerevisiae S288C under acetic acid, furfural and vanillin stresses.

Abstract:Bacitracin is a broad-spectrum polypeptide antibiotic, which is formed by 11 amino acids residues. Precursor amino acids supply might be the limit factor during bacitracin fermentation. First, our results demonstrated that increasing Ile and Leu supplies were regarded as the efficient strategies for the enhanced titer of bacitracin. Then, the amino acid permease YhdG, which was identified as the BCAA permease, was deleted and overexpressed in DW2, respectively. Our results showed that knocking out of permease YhdG could improve bacitracin production remarkablely. The bacitracin titer of the yhdG deficient strain DW2△yhdG reached 917.35 U/mL by flask fermentation, increased by 11% compared with that of DW2. In addition, the bacitracin titer was decreased by 25% in the YhdG overexpressed strain. Meanwhile, the intracellular concentrations of BCAA were higher than DW2 during the biosynthesis of bacitracin. The above results suggested that the permease YhdG might act as an exporter for branched chain amino acids in B. licheniformis DW2. Taken together, the increasing intracellular concentrations of branched chain amino acids by deleting amino acid permease YhdG could improve bacitracin titer. This study provided a new strategy for high-level production of bacitracin.

Abstract:In order to investigate the effect of S-adenosylmethionine decarboxylase (SAMDC) gene in melon resistance to powdery mildew, according to the previous results of EST sequences from cDNA-AFLP library and the melon genome sequence data, the SAMDC gene was isolated from Chinese wild melon clone ‘Yuntian930’ by RT-PCR and designated as CmSAMDC (GenBank Accession No. KF151861). The mORF (main open reading frame) was 1 095 bp encoding 364 amino acids with a molecular mass of 40 kDa. The predicted protein sequence showed high similarity with Cucumis sativus and Citrofortunella microcarpa. The SDS-PAGE showed that the expression protein was a fusion protein with the molecular weight of 40 kDa, which perfectly matched the mass calculated from the amino acid sequence. Quantitative real-time PCR analysis indicated that the expression level of CmSAMDC reached a maximum at 48 hpi (hours post inoculation) that over 7-fold to 0 hpi, and the expression of CmSAMDC was also detected in tendril, root, leaf and stem. These results indicate that CmSAMDC gene may play protective roles in melon resistance to powdery mildew infection.

Abstract:In order to find the insect-resistant composition and differentially expressed proteins of mungbean, Jinlv No.7, B20 and Weilv 2117 were used as experimental materials, and the differential proteins and functions of mungbean varieties that are resistant and susceptible to bruchids were compared and analyzed by two dimensional gel electrophoresis (2-DE) and identified by mass spectrometry. Among the samples, 15 protein spots showed a more than 2.5 times reproducible up-regulated, significance 6 of them were successfully identified by the database, and involved three kinds of proteins. They are the alpha and beta subtype 8S globulin, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBis CO) subunits binding protein and the precursor peptide chains for amylase inhibitor and trypsin inhibitor. The protein expressions of B49 (alpha subtype 8S globulin) and B31 (RuBis CO subunits binding protein) of insect-resistant mungbean were 10 000 and 23 times higher than that of insect-susceptible mungbeans. It stunted the growth and even death of the Callosobruchus chinensis L. that alpha and beta subtype 8S globulin and RuBis CO subunits binding protein and precursor peptide chains for amylase inhibitor and trypsin inhibitor of insect-resistant mungbean, the bruchid resistance effect of these three proteins need to further verified in terms of the quantity and the combined effect.

Abstract:In order to improve the nutritional value and bio-availability of sheep bone enzymatic hydrolysates, we tried to ferment the hydrolysates with lactic acid bacteria (LAB) to enhance free Ca2+, to generate oligopeptide and antioxidative activity. First, we isolated 7 LAB strains from commercial starters and selected Lactobacillus plantarum as the starter for its highest protease-producing ability. The content of released Ca2+ was evaluated when the fermenting conditions were optimized by the method of responsive surface design. When supplemented with 1% maltose and inoculated 4% L. plantarum, at initial pH 5.5 and 37 ℃ for 14 h, Ca2+ content in the hydrolysates increased significantly (P<0.05), as well as the generation oligopeptide (P<0.01), and the content of hydroxyproline (P<0.01). The count of L. plantarum in the fermented hydrolysates reached to 94.6×108 CFU/mL. L. plantarum fermentation significantly enhanced the ability to scavenge free radicals DPPH, ·OH and O2-· (P<0.01, P<0.05). Therefore, fermenting sheep bone hydrolysates by L. plantarum can increase free Ca2+, oligopeptide and antioxidative ability.

Abstract:PPP2R2A is one of the regulatory subunits of the PP2A phosphatase complexes, and previous studies showed that its upregulation promotes cancer cell survival and growth. In this research, we used the tandem affinity purification and the HPLC-Chip-ESI/MS/MS mass spectrometry to screen the PPP2R2A-binding proteins and the results indicated that the GFPT-1/-2 were the potential partners of PPP2R2A. We further validated the interaction between PPP2R2A and GFPT-1/-2 through GST Pull-down, co-immunoprecipitation and immunofluorescence assays. And we found that knockdown of PPP2R2A by lentivirus-mediated shRNA enhanced the phosphorylation of GFPT2, whereas the phosphorylation of GFPT1 had no significant change. GFPT2 is a rate-limiting enzyme in the hexosamine pathway. Our results showed that the knockdown of PPP2R2A promoted the total cellular O-GlcNAcylation in MDA-MB-231 breast cancer cells. These results suggest that PPP2R2A interacts with GFPT1/2, and leads to the phosphorylation of GFPT2, which can regulate the cellular O-GlcNAcylation.

Abstract:Recombinant human interferon beta (rhIFN-β) is a glycoprotein produced by genetically engineered cells and has anti-virus, anti-tumor and immunoregulation functions. Although studies have shown that other subtypes of IFN such as IFN-γ affects cell proliferation and differentiation to some extent, the effect of rhIFN-β on chondrogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs) is less known. In this study we studied the effect of rhIFN-β on the chondrogenic differentiation of hMSCs by inducing hMSCs into cartilage pellet via adding IFN-β1a into regular TGF-β3 chondrogenic differentiation medium. We collected the induced pellets and then detected GAG content, assessed pellets size, observed agreecan using alcian blue staining, and analyzed the expression of Sox and CollangenⅡusing real-time PCR and Western blotting. Addition of 100 ng/mL IFN-β1a to regular TGF-β3 chondrogenic differentiation medium could improve the concentration of GAG, increase the size of pellets, promote the formation of aggrecan and up-regulate the expression of CollangenII and Sox9. IFN-β1a combined with TGF-β3 could promote chondrogenic differentiation of hMSCs.

Abstract:The objectiue was to explore how to improve stem cell derivation from human great saphenous vein. After the saphenous vein was cut into small pieces, the cells of the vessel wall were obtained by tissue adherent method and digestion with type Ⅱ collagenase. The morphological changes of blood vessel wall were observed under inverted microscope. The survival of vascular wall cells was assessed by trypan blue staining. Stem cells doubly positive for CD34 and CD117 were sorted out by immunofluorescent staining and flow cytometry. The cells obtained by tissue adherence method exhibited signs of fibrotic changes and aging at the third passage (P3), while the cells extracted by enzymatic digestion still showed colony-like growth. Survival rates of these two groups of cells were (91.7±1.2)% and (97.2±0.7)%, (P=0.005). The results of flow cytometry showed that the positive rates of CD34 and CD117 double positive cells in these two groups were (0.16± 0.05)% and (0.44±0.07)%, respectively, with statistical significance (P=0.005). Immunofluorescent staining showed that the positive rates of double positive stem cells in the two groups were (89.41±2.06)% and (94.03±1.83)%, P<0.05 one week after the sorted stem cells were cultured. The positive rates of CD31, VEGF2 and SMA in the stem cells determined by flow cytometry were (0.12±0.01)%, (0.19±0.02)% and (0.45±0.01)%, respectively, which were not statistically different from those of the control groups. This could rule?out substantial inclusion of mature endothelial cells and smooth muscle cells. Tube forming experiment confirmed that these vascular stem cells had developmental plasticity. More viable and morphologically healthy vascular stem cells can be derived by enzymatic digestion. These cells can be widely used in clinical and basic research.

Abstract:At present, the experimental technique to produce human red blood cells in vitro is complicated, and in order to optimize the induction steps, human pluripotent stem cells were differentiated into red blood cells through two induction steps. First, human pluripotent stem cells (including Rh negative A type umbilical cord mesenchymal stem cells (hUCMSCRh-A) and human iPS cells (hiPS)) were differentiated into CD31+ and CD34+ cells in BVF medium. PCR and flow cytometry were used to exam the expression of CD31 and CD34. We found that hUCMSCRh-A derived CD31+ and CD34+ cells were 5.3% and 22.7%, respectively; hiPS derived CD31+ and CD34+ cells were 31.2% and 8.2%, respectively. For the second induction step, the obtained CD31+ and CD34+ cells were differentiated into mature erythrocytes for 36 days under the addition of various growth factors. Through Giemsa staining, we found that the obtained mature erythrocytes were similar in morphology and size to normal human erythrocytes, and some obtained erythrocytes were enucleated. Globin expression was detected by real time RT-PCR, and the expression of β-globin was more than 20%. The obtained erythrocytes are collected into the centrifuge tube, and then erythrocytes were naturally settled and showed the red color. Our findings provide a novel and effective method for the quantity generation of human red blood cells in vitro.

Abstract:Given the increasing exploitation of antibodies in different contexts such as molecular diagnostics and therapeutics, it would be beneficial to unravel properties of antigen-antibody interaction with modeling of computational protein-protein docking, especially, in the absence of a cocrystal structure. However, obtaining a native-like antigen-antibody structure remains challenging due in part to failing to reliably discriminate accurate from inaccurate structures among tens of thousands of decoys after computational docking with existing scoring function. We hypothesized that some important physicochemical and energetic features could be used to describe antigen-antibody interfaces and identify native-like antigen-antibody structure. We prepared a dataset, a subset of Protein-Protein Docking Benchmark Version 4.0, comprising 37 nonredundant 3D structures of antigen-antibody complexes, and used it to train and test multivariate logistic regression equation which took several important physicochemical and energetic features of decoys as dependent variables. Our results indicate that the ability to identify native-like structures of our method is superior to ZRANK and ZDOCK score for the subset of antigen-antibody complexes. And then, we use our method in workflow of predicting epitope of anti-Ebola glycoprotein monoclonal antibody—4G7 and identify three accurate residues in its epitope.

Abstract:With the sequence of the vasoactive intestinal peptiepeptide (VIP) from humans and according to the condon bias of Pichia pastoris, we designed PCR primers of VIP and obtained the sequence of VIP by SOE-PCR. Then VIP gene was cloned into Pichia pastoris secretory expression vector and the cell secretary system GS115-pPICZαA-vip was constructed. The recombinant strain was induced by methanol for 96 hours, and we collected the supernatant and identified the VIP by mass spectrometry. The molecular weight of VIP was consistent with theoretical molecular weight. The final result showed that the target peptide VIP was successfully expressed. The experimental investigations of agarose gel diffusion revealed that the recombinant expression modified VIP had relatively strong antibacterial activity to E. coli ATCC25922 and S. aureus ATCC25923. The minimal inhibitory concentration (MIC) of VIP to E. coli ATCC25922 and S. aureus ATCC25923 was 8 mmol/L and 16 mmol/L. Further cytotoxicity and hemolytic experiments indicated that recombinant VIP was non-toxic to normal cells NCM460 and IPEC-J2, had little hemolysis activity to SD rat erythrocytes. Meanwhile, by transmission electron microscopy, we found that VIP mainly inhibited bacteria by disrupting the cell membrane. These experiments established a useful system for further studies, application and mass production of antimicrobial peptide VIP.

Abstract:To establish a time-resolved fluorescence immunochromatographic assay for quantitative determination of carbohydrate antigen 19-9 (CA19-9) in serum, we prepared CA19-9 test strips by integrating double-antibody sandwich method and fluorescence immunochromatography technique. Carboxy fluorescent microspheres and nitrocellulose membrane were used as carriers for labeling and coating CA19-9 pairing antibodies. We optimized the process by adjusting the amount of labeling and coating antibody. According to the linear range, lowest detection limit and precision, We evaluated the time-resolved fluorescence immunochromatographic assay of CA19-9. When the amount of labeled antibody was 80 μg for 20 μL fluorescent microspheres, and the concentration of coated antibody on the test line was 1.5 mg/mL, the optimal reaction time was 15 minutes. Assay linear range was 12.5 to 800 U/mL and the minimum detection limit was 6.32 U/mL. The Within-run and between-run coefficient of variation were less than 15%. Average recovery rate was 101%. By detecting 50 clinical samples in parallel with Roche electrochemical luminescence detection kit, correlation coefficient was 0.980 6. The experiment, initially established a fluorescence immunochromatographic detection method to quantitative detection of serum CA19-9, which has a good clinical application prospect.