Abstract:Toll like receptors (TLRs) are pattern recognition receptors and represent immune receptors in innate immunity. They are very conservative in evolution and extremely important for the survival of organisms. TLRs initiate signal transduction through binding of endogenous or exogenous ligands to activate a series of downstream important gene expression and activation. Studies have shown that regulatory T cells (Tregs) play a central role in maintaining peripheral immune tolerance and preventing transplant rejection. Tregs express certain TLRs, including TLR2, TLR4, TLR5, TLR7, TLR8, and TLR9. Activation of TLRs may directly or indirectly affect (mainly activate) Treg proliferation and immunosuppressive functions, and this regulation is closely related to the occurrence of infection, autoimmune disease and cancer. The heat shock proteins as TLRs ligand molecules play important roles in the regulation of Treg. Therefore, understanding regulatory mechanisms of TLR pathways on Tregs is of great significance for new drug development and targeted therapy. This review introduces how TLR-mediated pathways regulate Tregs’ immune function.

Abstract:The incidence of heart failure (HF) increases significantly as people age. HF remains a major concern in public health. Although remarkable achievements have been made to treat heart failure in recent years, the survival rate of patients is still very low and the prognosis is poor. The mortality rate within 5 years after the diagnosis of heart failure is up to 50%. If we can quickly and effectively diagnose heart failure and reasonably stratify according to the risk, it will provide a solid foundation for clinicians to formulate treatment plans. Biomarkers play an important role in the diagnosis, curative effect evaluation and prognosis of heart failure. Heart failure is a complex disease in which various pathophysiological processes are involved over time. When heart failure occurs, neuroendocrine system is activated. With the increase of blood volume and ventricular wall pressure, ventricular myocytes secrete NT-proBNP/BNP. Therefore, NT-proBNP/BNP can be used as a biomarker for diagnosis and prognosis of heart failure. However, NT-proBNP/BNP in plasma is easily affected by many factors such as age, sex, body type, left ventricular hypertrophy, tachycardia, right ventricular overload, hypoxemia, and kidney function. As a novel marker of heart failure, sST2 has attracted much attention in recent years. It can reflect the degree of myocardial fibrosis and predict whether ventricular remodeling will occur. It is worth noting that sST2 is not affected by age, gender and renal function and other factors. Also, with low reference change values and individuality index values, sST2 seems to be the best candidate for monitoring and guided therapy. In short, sST2 is one of the ideal indicators to evaluate heart failure. This review summarizes the research progress of sST2 in the diagnosis and prognosis of heart failure in recent years, and provides perspectives for its future development.

Abstract:In order to achieve better tumor treatment, researchers have designed dual and multiple responsive smart nanocarriers in the tumor microenvironment. Among them, the research based on acid-sensitive dual-responsive nanocarriers is the most extensive and common one. Intelligent nanocarriers have initially achieved long circulation in body, effective accumulation in tumor cells, and controlled drug release in tumor microenvironment, with increased anti-tumor effect of drug and reduced damage to normal tissues. However, there are still many problems to be solved in current research, such as high price, complicated nanocarriers structure, and unclear mechanisms of drug delivery in the body, all hampering nanocarriers from clinical applications. This article introduces the progress of nanocarriers in recent years from the dual responsive aspects including acid-temperature, acid-magnetism, acid-redox, acid-enzyme, acid-light and acid-ultrasound, to provide reference for further clinical application of nanomedicine.

Abstract:Exosomes are a class of small extracellular vesicles. The lipid double-layer membrane envelops bioactive molecules including proteins and nucleic acids, which is transported throughout the body through the body fluid. Previous studies have indicated that exosomes play significant roles in viral infection. Viruses need to complete the life cycle in the host cells and release nascent virions, which partially coincides with the production and secretion of exosomes. On one hand, viruses hijack exosomes, and load their components into exosomes to escape from the host immune response and promote the replication. On the other hand, the host seizes exosomes to deliver antiviral factors to resist viral infection. The purpose of this review is to provide new insights into relevant research by discussing the roles of exosomes in viral infection from the perspective of both viruses and hosts.

Abstract:Mycoplasma hyopneumoniae is the pathogen of porcine enzootic pneumonia (PEP). Due to difficulties in studying the pathogenesis of M. hyopneumoniae for blockage on the establishment of gene operation platform and immature animal model, mycoplasmologists still make progress in understanding the interaction between M. hyopneumoniae and host. In this paper, we review the adhesion and damage of M. hyopneumoniae to host cells, the inflammatory response and immune response of host stimulated by M. hyopneumoniae. Meanwhile, we propose research directions of the pathogenesis of M. hyopneumoniae in the future. This review can provide references for the follow-up study on the interaction between M. hyopneumoniae and host, and provide theoretical basis for effective vaccine and drug development.

Abstract:As an ancient and huge family of membrane proteins, ATP-binding cassette transporter (ABC transporter) plays an important physiological role in most organisms. Herein, we introduce the research progress in ABC transporters on the aspects of structural characteristic, transport mechanism and physiological functions. We also focus on the application of ABC transporters in the field of synthetic biology in recent years. Finally, we propose future research needs.

Abstract:Natural silks, produced by spiders and silkworms, are excellent materials with marvelous mechanical properties, biocompatibility and biodegradability, and widely used in the fields of textile, optics, electronics, biomedicine and environmental engineering. So far, there are many spinning methods to improve the mechanical properties of artificial fibers, such as wet spinning, dry spinning, and electrospinning. However, the performance of most artificial fibers is still inferior to natural silks. It is important to understand the correlations between hierarchical structures and performance in the field of artificial spinning. This review introduces the formation of natural silks, the relationship between the mechanical properties of silks and the hierarchical structure, the research progress in artificial spinning, and the application of silks.

Abstract:Epigenetic nucleoside modifications are critical for the stability and translational efficiency of messenger RNA. Depending on the organism, developmental stage, and tissue/organ investigated, the location and abundance of these nucleoside modifications may differ, which in turn influence the splicing event, half-life time of mature mRNA, as well as translation efficiency. Among the approximately 170 RNA nucleoside modifications, only a handful are found in mRNAs. The low abundance and high organ specificity make it a challenging work to study the role of each specific mRNA nucleoside modification. However, with the technical advances in recent years, including meRIP, great progress has been achieved, especially on the function of m6A and m5C epigenetic markers in eukaryotes. This review summarizes recent progress on nucleoside modifications of messenger RNAs, on their distribution on transcripts and their role in regulating growth and development. We also discuss the technical bottleneck and key issues for future investigation.

Abstract:Asymmetric reductive amination is one of the most important reactions in the preparation of chiral amine pharmaceutical intermediates. Different kinds of enzymes have been applied to the synthesis of chiral amines Among them, the development of reductive amination reactions catalyzed by NAD(P)H-dependent oxidoreductases is attractive, as it would permit a one-step transformation of prochiral ketones into chiral amines with high optical purity. In this review, the recent advances in enzyme structure, catalytic mechanism, protein engineering and the application in reductive amination reactions of NAD(P)H-dependent oxidoreductases, including imine reductase, amino acid dehydrogenase, opine dehydrogenase and reductive aminase, are summarized.

Abstract:In order to clarify the regulation of granule cell stimulating factor (GCSF) on granulosa cells, we studied the effect of GCSF on proliferation and apoptosis of in vitro cultured granulosa cells for research on GCSF used in sheep reproduction and breeding. Sheep GCSF protein was prokaryotic expressed and purified. Its bio-activity was measured with M-NSF60 cells. The purified GCSF was added in cell culture medium in experiment groups with non-added as control. Alarmarblue was used to measure cell proliferation, and flow cytometry was used to detect cell cycles and apoptosis. Sheep GCSF could be expressed and purified. Cell activity increased with GCSF concentration from 0.06 to 600 ng/mL at 24 h and 48 h. Cell cycles were significantly different between experiment and control groups at 24 h. Cell ratio of S was significantly reduced (P<0.05) and G2/M phase significantly increased (P<0.05). The apoptosis ratio of experiment group was significantly reduced (P<0.05) at 48 h. In conclusion, GCSF could enhance cell proliferation, inhibit apoptosis, and regulate cell cycles on in vitro cultured sheep granulosa cells.

Abstract:(R)-(+)-1-(1-naphthyl)ethylamine is a key chiral intermediate for the synthesis of calcimimetic drug cinacalcet hydrochloride. ω-Transaminase has been considered to be potential for producing (R)-(+)-1-(1-naphthyl)ethylamine by asymmetric reduction of 1-acetonaphthone. Here, ω-transaminase from Arthrobacter sp. was engineered by combinatorial strategies of random mutagenesis and semi-rational design. Variants F225M, C281I, F225M/C281I with improved catalytic efficiency and thermostability were obtained. Compared with WT, variant F225M/C281I showed 85% increased kcat, 56% decreased Km and 3.42-fold kcat/Km. Furthermore, 22% higher conversion rate was achieved by F225M/C281I at 10 mmol/L 1-acetonaphthone after 24 h. Based on molecular docking and molecular dynamics simulation, improved catalytic efficiency of F225M/C281I could be attributed to its increased Pi-Pi T-shaped interaction with substrate 1-acetonaphthone. Additionally, a slightly higher half-life of F225M/C281I was validated by its lower root-mean-square fluctuation (RMSF) value of loop 134–139 compared with WT.

Abstract:p-Coumaric acid is an important precursor of various natural compounds, such as flavonoids and stilbenes. It has been widely used in biomedicine, food, nutrition and health care industries. Compared with traditional plant extracts and chemical synthesis, microbial synthesis of natural compounds such as p-coumaric acid has attracted wide attention due to its short production cycle and high conversion efficiency. Here a p-coumaric acid-producing Saccharomyces cerevisiae platform strain was developed. First, the tyrosine synthesis competition pathway genes ARO10 and PDC5 were knocked out, and ARO4K229L and ARO7G141S were mutated to release negative feedback inhibition from tyrosine. The tyrosine ammonia-lyase coding gene TAL from Flavobacterium johnsoniaeu was then integrated into genome and obtained C001 with yield of p-coumaric acid 296.73 mg/L. To further increase the accumulation of p-coumaric acid precursors, 8 genes encoding amino acids and carbohydrate transporters were knocked out and the gluconeogenesis pathway was enhanced. The results showed that GAL2 knockout and overexpression of EcppsA increased the yield of p-coumaric acid to 475.11 mg/L. Finally, the effect of FjTAL anchoring to yeast vacuoles on product accumulation was analyzed, and the highest titer of p-coumaric acid of 593.04 mg/L was obtained after intracellular vacuolar localization of FjTAL. It provided an efficient p-coumaric acid-producing platform strain for the subsequent synthesis of flavonoids and stilbene compounds by enhancing the supply of precursors, blocking the competitive bypass pathway, and using the strategy of subcellular localization.

Abstract:Mannanase and xylanase, the main hemicellulolytic enzymes, are widely used in food, feed, textile and papermaking industries, and usually they are used in combination. Mannanase Man5A from Talaromyces leycettanus JCM12802 consist of the carbohydrate binding module (CBM), linker region and catalytic domain. The CBM coding region of Man5A was removed and fused to C-terminal of the xylanase gene Tlxyn11B. The fusion gene Tlxyn11B-linker-man5A was successfully expressed in Pichia pastoris and the fusion protein Tlxyn11B-Man5A was purified and characterized. The theoretical molecular weights of Tlxyn11B, Man5A without CBM region, and Tlxyn11B-Man5A are 21.6 kDa, 41.0 kDa, and 62.6 kDa, respectively. The fusion protein had high xylanase and mannanase activities. The optimal temperature of the fused xylanase is 70 °C, which is 5 °C higher than Tlxyn11B-w (xylanase before fusion). The fused mannanase exhibited maximal activity at 90 °C, which is similar to Man5A-w (mannanase before fusion). More than 48% of xylanase activity of Tlxyn11B-Man5A was residual after the condition of 60 °C with 1 h, which is significantly higher than Tlxyn11B-w (only 20% of activity was left at 60 °C for 20 minutes). The optimal pHs of Tlxyn11B-Man5A for xylanase and mannanase activity are 4.0 and 5.0, respectively, which are 0.5 and 1.0 units higher than those of Tlxyn11B-w and Man5A-w. The pH range of fused enzymes got wider and the pH stability is improved. The specific activities of xylanase and mannanase of Tlxyn11B-Man5A are 1 784.3 U/mg and 1 639.6 U/mg, respectively, which is lower than those of Tlxyn11B and Man5A (8 300.0 U/mg and 1 979.0 U/mg). It may be due to of the high molecular weight of fusion enzyme. The Km and Vmax of the fused xylanase and mannanase are 1.2 mg/mL and 1.7 mg/mL, 2 000.0 μmol/(min·mg) and 2 831.6 μmol/(min·mg), respectively. Tlxyn11B and Man5A were successfully fusion expressed in P. pastoris, and the good properties of fusion of xylanase and mannanase make it has great application potential in animal feed, food and other industrial production, and it provided new ideas for the improvement of enzyme performance.

Abstract:With the popularity of green concepts, the use of biological method to synthesize metal nanoparticles is a favored method. Silver nanoparticles (AgNPs) have attracted more and more attention in the control of agricultural diseases, because of their strong antifungal activity and not easy inducing resistance for pathogens. In this study, Trichoderma citrinoviride and Trichoderma velutinous were used to study the most suitable synthesis conditions for AgNPs, and their antifungal activity against Fusarium oxysporum. The silver nanoparticles had an absorbance peak at 400-500 nm, the most suitable synthesis conditions were at standing and light with CL method (mycelium filtrate), AgNO3 concentration of 2.0 mmol/L, pH of 7, and reaction temperature of 45 °C. AgNPs synthesized by T. citrinoviride and T. velutinous inhibited F. oxysporum, the inhibition effect was better with the increase of silver nanoparticle concentration. When the concentration of AgNPs was 200 mg/L, the antifungal rate from T. citrinoviride and T. velutinous was 33.75% and 36.08%, respectively.

Abstract:Jasminum sambac is a perennial evergreen shrub plant. With fragrant and aroma, and often used as a raw material for natural spices. In this study, we used white light as the control group, red-light and blue-light as the treatment to study effects of different light on jasmine flowering. Red- light promoted jasmine flowering in advance and increased the number of flower buds, whereas blue-light delayed jasmine flowering and decreased the number of flower buds. There was significant difference on the number of flower buds among the three groups. The top buds’ transcriptomes of different light were sequenced by the Illumina Hiseq/Miseq 2000 high-throughput sequencing technology. In total 2 452 457 Unigenes were generated by transcriptome sequencing, of which 1 760 723 Unigenes were annotated into GO, COG, KEGG, KOG, NR, Pfam, Swiss-Prot, NOG databases. There were 894 DEGs in the control group vs red-light group, 2 690 DEGs in the control group vs blue-light group, and 3 828 DEGs in the red-light group vs blue-light group. KEGG Enrichment analysis reveals that the significant enrichment pathways had 6 pathways, including secondary metabolite biosynthesis, phenylpropanoid biosynthesis, indole alkaloid biosynthesis, photosynthesis, plant hormone signaling, and plants-pathogen interactions, and 24 related DEGs were detected by RT-qPCR, the result of which was significantly correlated with the transcriptome data. Through further analysis of transcriptome data, a large number of flowering-related hormones (IAA, ETH, GA, CTK, ABA, SA, JA) signal transduction genes and flowering pathway-related regulatory genes (PHY, CRY1, FPA, AGL and SOC1) and transcription factor (bHLH, MYB, WKRY) family genes were found. The study will help elucidate the differential expression mechanism of different light regulation of jasmine flowering.

Abstract:We studied the influence of Lactobacillus reuteri SL001 (L. reuteri SL001) on the gut microbial community in Alzheimer’s disease model mice (APP/PS1 double transgenic mice, ADmice) and wild type (C57BL/6) mice. The AD model mice and wild type mice were divided into test and control groups (4 in total), with 5 mice each and only male mice. The test group was fed with 0.2 mL suspension of L. reuteri SL001 at 5×1011 CFU/mL. The control group received the same amount of sterile PBS daily for 45 days. Fecal samples were collected to compare and analyze the community structure and diversity of microbiota through high-throughput sequencing of the V3–V4 region of 16S rRNA gene. By sequence alignment and classification, the intestinal microbial OTUs of the 4 groups including 19 phyla, 40 classes, 64 orders, 104 families and 175 genera. The α diversity of AD model mice was greater than that of wild type mice, but the difference between the two was small. After adding L. reuteri SL001, the α diversity of both mice increased, and the increase in AD model mice was smaller. At the phyla level, the dominant phyla of the four groups of mice were Bacteroidetes, Firmicutes and Proteobacteria. The abundance of Bacteroides phylum in AD model mice was lower than that of wild type, and the abundance of chlamydomonas was higher than that of wild type. Feeding L. reuteri SL001 reduced the proportion of Firmicutes/Bacteroidetes (F/B) in mice. At the order level, the relative abundance of Bacteroidales, Lactobacillales, Bacillales and Bifidobacteriales in AD model mice was lower than that of wild type mice. At the genus level, the abundant genera were Allobaculum, Lachnospiraceae_NK4A136_group, Bacteroides and Lactobacillus. The relative abundance of Bacteroides, Lactobacillus, Bifidobacterium and Alloprevotella in AD model mice was lower than that in wild type mice. Adding L. reuteri SL001 increased the abundance of these genera and Bacteroides, Lactobacillus, Bacillus and Bifidobacteria in AD model mice. The relative abundance of Butyrivibrio in AD model mice was also lower than that in wild type, but after the feeding of L. reuteri SL001, the relative abundance was reduced in both mice. The dominant strains of wild-type mice were Lactobacillus, and no dominant flora was found in AD model mice. The results in this article provide valuable data for revealing the difference in intestinal microbial diversity between AD model mice and C57BL/6 mice, and feeding L. reuteri SL001 play positive roles in adjusting the intestinal bacterial community structure of AD model mice.

Abstract:The main purpose of this research is to synthesize and evaluate a new glycoconjugate vaccine against Klebsiella pneumonia (Kp). First, the gene (waaL) responsible for the expression of O antigen ligase was deleted to block the synthesis of bacterial LPS. Then the vector that encodes a glycosyltransferase (PglL) was transferred into the mutant. The enzyme PglL could catalyze the transfer of OPS units to recombinant cholera toxin B subunit (rCTB) to form glycoproteins in vivo. The protective effects of the glycoproteins were studied by the mice models with acute bacteremia that were induced by intraperitoneal injection of wildtype Kp bacteria. The results were as followings: A Kp waaL mutant was obtained and the rCTB protein could be successfully glycosylated in the mutant. The vaccine can stimulate a high antibody titer in the mice sera with or without adjuvant. It can also protect mice from the lethal dose injection of Kp. The survival rate of vaccine candidate groups could reach 75%. The glycoconjugate vaccine candidate prepared by this biosynthetic method is expected to become a novel effective vaccine against Klebsiella pneumoniae.

Abstract:Glucose biosensor is currently the most common electrochemical biosensor. Most glucose biosensors are prepared by modifying glucose oxidase on the electrode surface. However, in the process of electrode immobilization, enzyme purification is required, which increases the cost and has become a bottleneck in the field of development of immobilized enzyme electrodes. In this study, glucose oxidase (GOD) was displayed on the surface of Bacillus subtilis using the spore capsid protein CotX as an anchor protein. By Western blotting analysis, immunofluorescence analysis and enzyme activity detection, GOD was effectively expressed on the surface of spores, and recombinant spores (Spore-GOD) were obtained by fermentation. The graphene oxide/prussian blue deposition film modified glassy carbon electrode was prepared by the drop coating method and the electrodeposition method. The surface of the modified electrode was fixed with Spore-GOD, and finally covered with a layer of Nafion solution to make an electrochemical biosensor for sensitive determination of glucose. The cyclic voltammogram of glucose on the enzyme electrode sensor showed a well-defined oxidation peak at 0.42 V, and the redox peak current has a good linear relationship with the glucose concentration in the range of 0.1–7.0 mmol/L. The calibration curve equation is: I=1.305Cglucose+3.639 (R2=0.992 9), and its detection limit is 7.5 μmol/L (S/N=3). This modified electrode has good conductivity, stability and reproducibility, and can be used for the analysis and determination of glucose.

Abstract:2-O-α-D-glu-copyranosyl-sn-glycerol is a high value-added product with prospective application in food, cosmetics, health products and pharmaceutical industries. However, industrial scale of 2-O-α-D-glu-copyranosyl-sn-glycerol has not yet been applied in China, and there are few related reports on 2-O-α-D-glu-copyranosyl-sn-glycerol synthesis. The purpose of this experiment is to develop a method for catalyzing the synthesis of food-grade 2-O-α-D-glu-copyranosyl-sn-glycerol using whole cells of “Generally Recognized as Safe” (GRAS) recombinant Bacillus subtilis. In our work, a recombinant B. subtilis 168/pMA5-gtfA that heterologously expressing Leuconostoc mesenteroides sucrose phosphorylase was constructed and used as a whole-cell catalyst to synthesize 2-O-α-D-glu-copyranosyl-sn-glycerol. Optimizing the culture temperature, time and whole cell transformation conditions has increased the yield of 2-O-α-D-glu-copyranosyl-sn-glycerol. The results showed that 1.43 U/mL of sucrose phosphorylase was achieved in B. subtilis 168/pMA5-gtfA after culturing for 20 h at 30 °C in fermentation medium. The highest conversion rate reached 75.1%, and the yield of 2-O-α-D-glu-copyranosyl-sn-glycerol was 189.3 g/L with an average transformation rate of 15.6 mmol/(L·h) after 48 hours whole-cell transformation with the sucrose concentration of 1 mol/L and the glycerol concentration of 2.5 mol/L at 30 °C, OD600 40 and pH 7.0. This is the highest yield of 2-O-α-D-glu-copyranosyl-sn-glycerol synthesized catalytically by recombinant B. subtilis that was ever reported, and this study provides the theoretical and experimental basis for the industrial production and application of 2-O-α-D-glu- copyranosyl-sn-glycerol.

Abstract:ω-transaminase (ω-TA) is the most promising biocatalyst for chiral amine synthesis. However, most wild-type ω-TAs cannot be applied in industry directly due to their low stability and unfavorable reaction equilibrium. In order to discover a novel ω-TA for industrial application, we designed a procedure of adaptive selection, including the screening of substrates, protein sequences and clones, enzyme activity, and product conversion and characterization, as well as trouble-shooting of each step. Through this procedure, we screened a novel ω-TA, ATA-W12 of Caulobacter sp. from a soil metagenome. The strain could convert 20 mmol/L 1-Boc-3-pyrrolidinone and 20 mmol/L 1-Boc-3-piperidone with 85.84% and 67.42% conversion rate, respectively, in a 1-mL scale with isopropylamine (IPA) as amine donor. ATA-W12 maintained 100% activity at 40 °C for 168 h, and its optimal reaction condition is at pH 8.5 and 40 °C. These excellent properties benefit the application of IPA as an ideal amino donor in industry. We scaled up the production of (S)-(+)-1-boc-3-aminopiperidine up to 50 mL (100 g/L) scale with this novel biocatalyst for its further industrial application.

Abstract:New engineering program requires training models that conform acceptable time span and principles of engineering education. Considering the program “Principles of chemical engineering” and the limitations of traditional teaching methods, we integrated problem-based learning method and flipped classroom teaching model to reform the course. Through a three-stage systematic teaching design including knowledge learning before class, knowledge internalization in class, and consolidation and expansion after class, we effectively stimulated students’ interest and enthusiasm in learning, cultivated students’ independent learning ability and engineering thinking, and achieved good teaching effect. It can provide reference for the construction of “Principles of chemical engineering” course and training of engineering talents in agricultural colleges.

Abstract:Technical English is a compulsory course for brewing engineering undergraduates. To improve the quality and effectiveness of teaching, we introduced science, technology, engineering, arts and mathematics (abbreviated to STEAM) education theory in technical English teaching of brewing engineering students, and selected, designed, integrated and optimized the teaching contents. With the help of the Rain Classroom, Massive Open Online Courses of Tsinghua University (XuetangX), Open Language, Wine Folly, training courses of Wine and Spirit Education Trust (WSET) and other platform resources, teaching methods, assessment ways and multi-element teaching evaluation system have been innovatively reformed. By using advanced teaching methods such as mind mapping drawing, micro-video production, situational dialogues, topic speech, creative program design and design competition of wine label and bottle packaging, it could effectively improve students’ learning interest and engagement, and enhance students’ knowledge of professional English and comprehensive application ability.