The poor gel properties of fish gelatin limit its commercial application. Enzyme-catalyzed modification of fish gelatin has great advantages such as environmental friendliness, safety and high efficiency. However, there are few gelatin-modified enzymes reported at present, and most of them are covalent cross-linking enzymes, which easily make gelatin form thermal irreversible gel. In this study, two proline hydroxylases that increase the non-covalent action of collagen were cloned and expressed in prokaryotic cells. After purification, the fish gelatin was catalyzed respectively using two proline hydroxylases. The results show that the two enzymes have the effect of improving the gel strength and texture characteristics of fish gelatin. In addition, the surface display technology of Corynebacterium crenatum was studied. The two enzymes were displayed on the surface of C. crenatum, and an immobilized enzyme system with C. crenatum as the carrier was prepared for studying the modification effect of two immobilized enzyme systems on fish gelatin. This study has enriched the catalytic enzyme system of fish gel and provided a new idea for the catalytic modification of fish gelatin.
Tomato transcription factor SlNAC1 has been reported to regulate several biotic and abiotic stress responses, but its upstream regulatory transcription factors remain unknown, which limits our understanding of its molecular mechanism of stress responses. We constructed series of 5'-deleted SlNAC1 promoters (2 039 bp, 1 508 bp, 1 373 bp and 777 bp upstream of start codon) -driven GUS transgenic Nicotiana benthamiana and analyzed quantitatively their GUS activity under cold, heat and ABA treatment conditions in order to identify cold-, heat-, and ABA-responsive cis elements. Our results show that the GUS activity of 2 039 bp promoter-driven transgenic Nicotiana benthamiana increased much higher than that of any other transgenic Nicotiana benthamiana and wild-type Nicotiana benthamiana after cold and heat treatment, while the GUS activity of 1 508 bp promoter-driven transgenic Nicotiana benthamiana increased much higher than that of any other transgenic Nicotiana benthamiana and wild-type Nicotiana benthamiana after ABA treatment. These results indicate that both cold-responsive and heat-responsive cis elements were located in the region from -2 039 bp to -1 508 bp, and ABA-responsive cis element(s) was(were) located in the region from -1 508 bp to -777 bp. According to cis elements' prediction of SlNAC1 promoter, there were only one cold/heat/drought/salt-responsive cis element DRE/CRT in the region from -2 039 bp to -1 508 bp and only one ABA-responsive cis element ABRE in the region from -1 508 bp to -777 bp. Therefore, these two cis elements will be used as candidates for subsequent site-directed mutagenesis validation and screening of the upstream regulatory transcription factor of SlNAC1.
The nanobodies existing in the sera of camels and sharks have different structural characteristics and molecular weight from traditional monoclonal antibodies, as well as such characteristics as high specificity, high physicochemical stability and tissue permeability, which show great application potential and are considered to be promising therapeutic proteins in the development of biomedicine. Microorganisms are used to produce expression nanobodies without post-translational modification, which can be produced in large quantities and significantly reduce production costs. At present, the conventional expression systems for producing nanobodies are mainly Escherichia coli, Pichia pastoris, and mammalian cell lines, as well as fungi, plant cells, insect cells and lactobacillus expression systems. E. coli has the advantages of fast growth, high yield, easy culture and cost effectiveness. Pichia pastoris has high expression efficiency, can be cultured in high density, and uses methanol as the only carbon source to reduce pollution. Mammalian cells can adapt to serum-free suspension culture. On this basis, the research progress of characteristics, advantages and applications of different expression systems is reviewed, the urgent problems of each system are analyzed, and the production, research and development of therapeutic nanobody drugs and clinical disease treatment applications are summarized, in order to provide reference for the selection of appropriate expression systems for the production of therapeutic nanobodies and their applications in clinical treatment.
Mesenchymal stem cells (MSCs) are adult multipotent stem cells possessing the advantages of rich and wide sources, low immunogenicity, homing to the tissue of injury, paracrine activity, immunomodulation capacity, and easiness to be engineered. With the above-mentioned advantages, MSCs may have great application value in the treatment of cancer. Despite the controversial roles of MSC in cancer therapy, engineering MSCs with homing capacity to tumor tissues show great antitumor potential for delivering anticancer agents, suicide genes, and oncolytic viruses to tumors. Current clinical trial utilizing engineered MSCs in GBM treatment was shown to exert anti-GBM activity. Therefore, the following review elaborates on the characteristics of MSCs as well as the effects of engineering MSCs on tumor cells and their microenvironments, in order to provide new insights into MSCs’ value in translational medicine and tumor treatment.
Programmed cell death (PCD) is a collective term for the intrinsically regulated death of cells. Different forms of cell death are caused by their own programmed regulation during the growth and development of organisms and stress responses to the environment and diseases. PCD includes apoptosis, pyroptosis, necroptosis, autophagy and ferroptosis. It is not only essential for the growth and development of organisms, but also plays an important role in intervening in the process of pathogens invasion. Staphylococcus aureus can regulate various forms of PCD such as apoptosis, pyroptosis, necroptosis and autophagy in host cells, thereby affecting bacterial infection. This article reviews the crosstalk between Staphylococcus aureus infection and PCD to further understand the relationship between Staphylococcus aureus and cell death, in order to provide new ideas for the diagnosis and treatment of clinical Staphylococcus aureus infection.
Promoter is the most important element of initiation gene transcription and its function is closely related to the gene expression level. The promoter engineering aims to study the functional modification and directed evolution of promoters, which can expand and deepen the application of Saccharomyces cerevisiae promoters in synthetic biology. Based on the structural characteristics of S. cerevisiae promoters, this review focuses on the strategies and applications of S. cerevisiae promoter engineering, including regulatory sequence knockout, random mutation of traditional promoters, saturated mutation, promoter hybridization, synthesis of minimum promoter skeleton, and modification of transcription factor binding sites. In addition, the latest progress of CRISPR/dCas9 and artificial intelligence tools in the field of S. cerevisiae promoter engineering is introduced. The future development prospects of promoter engineering in the field of synthetic biology are also discussed.
Cyanobacteria have long been used as model organisms in basic biological research on topics such as photosynthesis, chloroplast origins and plant evolution. Additionally, due to their fast growth, simple culture techniques and convenient genetic manipulation, cyanobacteria have gained increasing attention in photosynthetic bio-manufacturing. One strategy for studying cyanobacteria is to first obtain mutants with specific phenotypes, and then further analyze their functional mutations and related mechanisms. Moreover, in the development of photosynthetic biomanufacturing technologies, enhancing the physiological tolerance of chassis cells is of significant importance for the large-scale application of cyanobacteria photosynthetic cell factories. Evolutionary engineering offers significant advantages in the acquisition of mutants and the optimization of complex physiological tolerance phenotypes, as it does not require knowledge of the microbial genetic background and metabolic network. This paper reviews the progress of evolutionary engineering in the analysis of cyanobacteria physiological metabolism mechanisms and the optimization of physiological tolerance in cyanobacteria photosynthetic biomanufacturing chassis, and meanwhile it also discusses the challenges and future directions of evolutionary engineering in cyanobacteria applications.
As a class of polymer polyester widely existing in microbial cells, Polyhydroxyalkanoate (PHA) has complete biodegradability and excellent biocompatibility, and is considered to be one of the most environmentally friendly bio-based polymer materials. In recent years, the utilization of synthetic biotechnology in genetically modified PHA-producing bacteria, coupled with the escalating demand for eco-friendly materials such as PHA in social and economic development, has led to significant advancements in PHA fermentation technology. However, the extraction cost has emerged as a pivotal factor impeding the commercial application of PHA. This article comprehensively summarizes the technologies and principles underlying various PHA extraction processes, encompassing physical, chemical and biological methods. Furthermore, it conducts a comparative analysis of the advantages and disadvantages associated with each extraction process, with the aim of providing valuable information and references for further cost reduction and efficiency enhancement in PHA extraction. Building upon the current state of PHA extraction process development, this article also presents prospects for the development of PHA extraction. Presently, PHA extraction processes typically combine multiple extraction methods to overcome the limitations of individual techniques; however, process conditions still necessitate optimization. The application of a novel PHA recovery biological system constructed using synthetic biotechnology holds great promise as the most effective strategy for reducing the cost of PHA extraction in the future.
Surface plasmon resonance (SPR) biosensors are a new type of biosensor technology based on the principle of SPR. They have numerous advantages including non-labeling, strong specificity, high sensitivity, and real-time dynamic detection, especially for the field of biological molecule interaction, drug-screening, etc. Many countries are stepping up their layout of intellectual property rights (IPRs) for SPR biosensor technology. The number of China’s intellectual property applications has increased significantly in recent years. Based on the IncoPat patent database, this study conducts an in-depth analysis on the overall development trend, intellectual property layout, popular technologies of SPR biosensors, and the identification of key IPRs. The results show that the SPR biosensor technology in China is becoming an increasingly active area of research, and China is ranked among the world’s leading countries in terms of the number of patent applications in this regard. However, several problems still exist, such as a small number of original IPRs, limited conversion rate of IPRs, and low market share of products. In view of the broad market prospects of SPR biosensor technologies, future development strategies of SPR biosensor technologies in China are proposed.
