Objective: Protein glycosylation plays an important role in regulating the immunogenicity of vaccines. The receptor-binding domain (RBD) of the spike protein of the novel coronavirus (SARS-CoV-2) contains two N-glycosylation sites (N331 and N343). This study aims to investigate the effect of RBD glycosylation on protein expression levels and immunogenicity. Methods: Wild-type RBD antigen and three N-glycosylation site mutations of RBD antigens, including wild-type RBD-WT and deglycosylated antigens (RBD-N1, RBD-N2, and RBD-2N), were constructed and expressed using glycosylation engineering yeast and mammalian cell expression systems. The purified antigens were obtained and the antibody levels induced by recombinant RBD vaccines were compared in immunized mice. Results: RBD glycosylation site mutations significantly affected protein expression levels, with similar characteristics in yeast and mammalian cell expression systems. Mutations at any N-glycosylation site resulted in decreased expression levels, especially when the N343 glycosylation site was mutated or both sites were mutated simultaneously. The results of RBD antigen immunization in mice showed that the mutation of the N343 glycosylation site resulted in a significant decrease in the titers of specific antibodies and neutralizing antibodies. Conclusions: Glycosylation modification is critical for the expression level and immunogenicity of the RBD protein, with the N343 glycosylation site playing a critical role in regulating protein expression level and immunogenicity.

Prolonged or excessive inflammatory responses can cause serious damage to the human body, and preliminary experiments have shown that the small molecule drug piceatannol (PCT) can be used as a potential anti-inflammatory drug. In this study, reactive oxygen species detection assay was used, and it was found that the alleviation of inflammatory injury in zebrafish gradually increased with the increase of PCT concentration within a certain safety range, and there was a dose-dependent effect on the degree of alleviation, indicating that PCT has an antioxidant effect. The effects on CuSO₄-induced cellular damage or oxidative stress-induced inflammation were investigated by using neutrophil- and macrophage-labelled transgenic zebrafish line Tg(coro1a:GFP;lyz:Dsred), in which zebrafish with CuSO₄-induced neuroinflammation were treated with different concentrations of PCT, and the number of neutrophils migrating to the site of the spinal neuronal hillock was significantly reduced, indicating that PCT has an antioxidant effect on the neuroinflammation. The number of neutrophils migrating to the site of vertebral neuromast was significantly reduced, indicating that PCT has a restorative effect on the aggregation of inflammatory chemotactic neutrophils at the site of injury. Meanwhile, the qPCR results demonstrated that PCT treatment significantly down-regulated the expression of inflammatory marker genes such as IL-6, COX-2 and TNF-α compared with the CuSO₄ treatment group alone, thus protecting zebrafish from CuSO₄-induced inflammatory injury. Our study demonstrated the anti-inflammatory and antioxidant effects of PCT in the zebrafish model organism, providing a theoretical basis for the future use of PCT as an anti-inflammatory drug.

Objective: To investigate the function and mechanism of the hypoxia-regulated factor zinc finger proteins 92 (ZNF92) in hepatocellular carcinoma cell growth and invasion. Methods: (1) The mRNA and protein expression levels of ZNF92 were detected by RT-qPCR and Western blot. (2) ZNF92 knockdown hepatocellular carcinoma cell line was established using lentiviral vectors. (3) The effects of ZNF92 on hepatocellular carcinoma HepG2 cells, and SMMC7721 cell growth and invasion in vitro were evaluated by CCK-8, scratch and transwell assays. (4) Small interfering RNA (siRNA) was used to determine the knockdown of ZEB1 expression and to determine whether ZNF92 indirectly regulates the epithelial-mesenchymal transition (EMT) process through ZEB1. (5) siRNA was used to determine the knockdown of HIF-1α and to detect the changes in cell migration and invasive ability. Results: (1) Hypoxia inhibited the mRNA and protein expression of ZNF92. (2) ZNF92 regulates the protein expression of zinc finger E-box binding homeobox 1 (ZEB1), a key transcription factor of EMT, thereby affecting the EMT process. (3) ZNF92 inhibits hepatocellular carcinoma migration and invasion without affecting the proliferation process. (4) ZNF92 partially regulates migration and invasion of hepatocellular carcinoma cells through ZEB1. (5) ZNF92 may partially regulate ZEB1 through HIF-1α to affect the migration and invasion of hepatocellular carcinoma cells. Conclusions: The novel hypoxia-inhibitory factor ZNF92 may affect the EMT process through HIF-1α, and then affect the migration and invasion of hepatocellular carcinoma cells by regulating ZEB1.

1,3-butanediol is an important diol used in chemical synthesis, food and medicine, daily chemical production, and more. In this study, Escherichia coli BL21 (DE3) was used as the host bacterium. The 1,3-butanediol metabolic synthesis pathway was constructed using acetyl-CoA acetyltransferase PhaA, NAD (P) H-dependent acetyl-CoA reductase PhaB1 and butaldehyde dehydrogenase Bld. On this basis, the effects of aldehyde-ketone reductase PA1127 and NAD kinase were explored. The effects of NADK on the metabolic production of 1,3-butanediol in recombinant strains were studied, and the culture conditions of 1,3-butanediol producing recombinant strains were optimized in order to improve the production of 1,3-butanediol in the recombinant strains. The recombinant plasmid was constructed in the form of multi-plasmid co-transformation system and multi-cis-trans subsystem, and the recombinant strain was obtained by transformation. After the conversion experiment or fermentation, glucose consumption was determined by the DNS method, bacterial volume and NADPH levels were compared by light absorption value, and 1,3-butanediol and by-products were quantitatively analyzed by GC and HPLC. The 1,3-butanediol metabolic synthesis pathway consisting of PhaA, PhaB1 and Bld was successfully constructed, and the conversion of glucose to 1,3-butanediol was realized. Overexpression of NADK improved the ability of recombinant strains to synthesize 1,3-butanediol, but increased the yield of acetic acid, lactic acid, ethanol and other by-products. By optimizing culture conditions and medium components during fermentation, the yield of 1,3-butanediol was increased to 0.531 g/L. This conclusion provides a theoretical basis for the study of 1,3-butanediol biosynthesis.

Genetic codon expansion technology utilizes orthogonal translation systems to achieve site-specific incorporation of non-canonical amino acids into target proteins by reprogramming codons. This technology extends the structure and function of proteins and has great potential in biotechnology, pharmaceutical research and other fields. The pyrrolysine orthogonal translation system has become a widely used codon expansion tool due to its unique orthogonality and substrate specificity. This article begins with an introduction to the key components and optimization methods of the pyrrolysine orthogonal translation system, including aminoacyl-tRNA synthetase and tRNA mutation strategies and non-canonical amino acid supply optimization strategies. Furthermore, various types of non-canonical amino acids incorporated by pyrrolysyl-tRNA synthetase variants are assembled and condensed. Next, the frontier progress of the pyrrolysine orthogonal translation system in protein function regulation, biomedical research, and non-L-α-amino acid coding is summarized to provide an overview. Finally, the current opportunities and challenges for the development of the pyrrolysine orthogonal translation system are explored.

Influenza is a highly contagious respiratory disease caused primarily by the influenza A virus. Influenza vaccine is one of the most economical and effective ways to prevent and control the widespread epidemics of influenza A viruses. Although various types of vaccines developed over the years have played a certain role in preventing and controlling influenza A virus infection, it is common that the antigens of vaccines and circulating strains do not match due to the existence of multiple subtypes of influenza viruses and their easy mutation and recombination, which often results in the injected vaccine not having a protective effect and frequent changes of vaccines. To effectively address this thorny problem, some research institutions and vaccine companies have turned to the development of universal or broad-spectrum influenza vaccines and have high expectations. This article systematically reviews the traditional influenza vaccines and the newly approved universal vaccines, both domestically and internationally. In particular, it highlights recent advances in DNA/mRNA vaccine research and development. It also discusses the future direction of universal influenza vaccine development. The aim is to provide guidance and support for the development of efficient and broad-spectrum new influenza vaccines, and to provide an important theoretical reference and technical basis.

The protein tyrosine phosphatase containing Src homology 2 (SH2) domain (SHP2) is the first oncogenic protein confirmed belong to the protein tyrosine phosphatase (PTP) family. It has the potential to regulate multiple signaling pathways, including RAS-RAF-ERK, PI3K-AKT, and JAK-STAT, making it an important target for anti-tumor drug discovery. SHP2 also plays a critical role in promoting tumor cell resistance and modulating immune cell function in the tumor microenvironment. The discovery of allosteric inhibitors has advanced the development of SHP2 drugs, with several allosteric inhibitor drugs currently in clinical trials as monotherapy or combination therapy. At the same time, proteolysis targeting chimeras (PROTACs), a novel drug design approach, are being widely used in the development of SHP2-targeting drugs. This article summarizes the clinical research results of allosteric inhibitors targeting SHP2, and outlines the progress of PROTAC-SHP2 drug development, with the aim of providing inspiration for the design and improvement of SHP2 drug molecules.

For tissue engineering, stem cells are a perfect source of seed cells, and their ability to track cells and regulate their fate in vivo is critical to understand the mechanisms and outcomes of tissue repair procedures. Numerous fluorescent materials have been developed for biological applications, among which near-infrared photoexcited lanthanide-doped upconversion nanoparticles (UCNPs) are novel fluorescent nanoparticles capable of emitting ultraviolet or visible light for stem cell bioimaging or fate regulation, which have a wide range of applications. A review of UCNPs is provided, with emphasis on their potential tracer and therapeutic utility. First, the structure and luminescence mechanism of UCNPs are briefly reviewed, followed by a detailed description of the means to enhance the biological properties of UCNPs. The stem cell imaging, tracking, and modulation of osteogenic, neural, and chondrogenic differentiation applications of UCNPs are then described. Finally, the understanding of the constraints and viewpoints of UCNPs in the field of stem cells is presented with the goal of bringing this field to the attention of more researchers.

Natural products are a class of valuable compounds, with a wide range of types and functions, widely used in medicine, food, chemical industry and other fields. With the development of synthetic biology, microbial cells have shown great potential in the synthesis of plant natural products, providing a new production approach for drug research and development, food science and the cosmetics industry. However, there are still many challenges ahead. Plant natural products have many bactericidal, anti-inflammatory and other pharmacological properties. Excessive production in microbial cells leads to toxic effects on the cells. At the same time, the accumulation of toxic intermediates in the synthesis process will also exacerbate cytotoxicity. It is therefore particularly important to improve the tolerance of microorganisms to plant natural products. In recent years, with the continuous regulation of microbial cell factories, the production of plant natural products has gradually increased, along with the research of microbial cell tolerance. However, there is rarely a systematic summary of the research area. Therefore, this paper aims to provide a comprehensive overview of the research on microbial cell tolerance to plant natural products, focusing on the strategies to improve microbial cell tolerance, the current major challenges, and the prospects for the development of this area.

Tylosin, a 16-membered macrolide antibiotic produced by Streptomyces fradiae, is used in clinical practice primarily to treat bacterial infections caused by Gram-positive bacteria. It is widely used in animal husbandry and has high economic value and academic research value. The structural features and mechanism of tylosin are presented. The research progress in the biosynthesis regulation mechanism, the breeding of high-yield strains of S. fradiae and tylosin heterologous biosynthesis strategy are summarized, which will provide a useful reference for in-depth understanding of tylosin biosynthesis and metabolic regulation.

In recent years, the development of small-molecule drugs has become increasingly challenging, while antibodies and other macromolecular drugs have tended to become more homogeneous. Peptide drugs, characterized by their unique molecular size, have experienced rapid growth due to continuous advances in peptide synthesis technology and extensive research into disease physiology. Owing to the advantages of broad indications, high safety profile, significant efficacy, and strong specificity, peptide drugs have been widely used in the diagnosis, prevention and treatment of various diseases, including oncology, cardiovascular and cerebrovascular diseases, and diabetes. As a result, they have immense potential and have become a major focus of new drug discovery and development. In order to promote the innovative development of peptide drugs in China, this paper provides a comprehensive summary of the synthesis technology utilized in peptide drug production while exploring the technical challenges encountered during its development process. By employing quantitative and qualitative analysis methods, a thorough analysis of the current status of peptide drug research and development along with market patterns at home and abroad is conducted. Furthermore, this study provides a comprehensive analysis of the opportunities and challenges faced by the industry participants. Finally, it assesses the future prospects for peptide drug development in China and provides targeted suggestions regarding technology research and development, key market players and industry standards, providing valuable references for researchers, industry practitioners, and relevant government departments.