Objective: In order to explore the effect of the NS2A-C60A gene mutation in the attenuation process on the biological characteristics of Japanese encephalitis virus. Method: First of all, the target research site NS2A-C60A that may be related to the expression of NS1' and virulence weakening was determined by sequencing and comparison of the genomes of the JEV attenuated strain and the original strain, prediction of the secondary structure of the 5'-terminal sequence of NS2A gene, and changes in NS1' protein expression; then, the NS2A-C60A single point mutation virus strain rJEV-C60A was rescued by using reverse genetic site-directed mutation technology; Finally, the influences on the biological characteristics for JEV were studyed by the observation of plaque morphology, growth curve, dual luciferase analysis, WB, inflammatory factor detection and animal experiments. Results: The research found for the first time that the passage attenuated of type Ⅰ JEV would lead to a significant decrease in NS1' protein expression and the related site NS2A-C60A, and successfully rescued the NS2A-C60A single point mutant strain rJEV-C60A. Plaque and growth curve results show that the NS2A-C60A mutation have no effect on the growth characteristics of JEV, but dual luciferase analysis and WB results reveal that NS2A-C60A mutation can significantly reduce the expression of viral NS1' protein. The results of inflammatory factors suggeset that the NS2A-C60A site mutation can slightly hinder the JEV suppression of inflammatory factors expression, but animal experiments show that the NS2A-C60A point mutation virus has similar neurovirulence to the original strain, indicating that the site mutation is not a key site that affects the virulence of JEV. Conclusion: The novel mutation NS2A-C60A can significantly reduce the expression of the JEV NS1' protein, but it has no significant effects on its other biological characteristics, like proliferation, induced inflammation and neurovirulence.
To investigate the functions of polyketide synthases (PKS) in Penicillium oxalicum SCSGAF0023, a marine gorgonian coral-associated fungus, the method of Agrobacterium-mediated transformation in P. oxalicum SCSGAF0023 was constructed and used to obtain the disruption mutants of Pks by homologous recombination. The roles of Pks in P. oxalicum SCSGAF0023 were characterized by multi-phenotypic analyses under normal and stressful conditions. An efficient genetic transformation system of P. oxalicum SCSGAF0023 was established under the condition of p0380-hygB being binary vector and conidia being the recipient. The transformation efficiency was the highest when 107 conidia/ml was co-cultivated with Agrobacterium tumefaciens AGL-1 with the OD600 of 0.5 under the induction of 200μmol/L acetoyringone (AS) at 25℃. Based on the Agrobacterium-mediated transformation, the disruption mutants of Pks were obtained, and it was the first reported that Pks positively regulated the conidiation but did not affect the environmental adaptation in P. oxalicum SCSGAF0023, which will be helpful for further investigation on the relationships between PKSs and fungal growth, development and environmental adaptation.
Objective: The highly stable EPS-nano-selenium complexes (E-SeNPs) were safely and simply prepared using Lactobacillus plantarum exopolysaccharides (EPS) as stabilizers and coating agents. The stability and antioxidant activity were also studied. Methods: The size, morphology, structure and stability of E-SeNPs were measured by transmission electron microscopy (TEM), dynamic light scattering (DLS), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform infrared spectroscopy (FT-IR). In addition, the antioxidant activity of E-SeNPs in vitro was evaluated by measuring the reducing ability and the clearance rate of ABTS+. Results: E-SeNPs with good dispersibility and stability were successfully prepared. The average particle size of the prepared E-SeNPs is (45.17±11.9)nm, with a negative charge (-31.3mV). Meanwhile, the E-SeNPs can be stable in the aqueous solution for 20 days. It was found by FT-IR analysis that the stability was due to the coating effect of EPS. Finally, at the same concentration, the reducing power and ABTS+ radical scavenging rate of E-SeNPs were significantly higher than those of EPS and selenium nanoparticles (SeNPs), showing good antioxidant activity. Conclusion: A new type of SeNPs stabilizer and coating agents were developed. It was simple and safe to prepare highly stable, water-dispersible SeNPs with good antioxidant activity.
Exosomes are the substance that are released by most types of cells and have an important role in cell to cell communication. They also have great potential as a medicine delivery carrier, especially suitable for delivery of therapeutic drugs, such as proteins, nucleic acids and gene therapeutic agents due to the inherent long-distance communication capacity and excellent biocompatibility. Many studies show that exosome can efficiently deliver many different kinds of cargo to the target cell. Therefore, they are often used to deliver therapeutic cargo for treatment. As a result, the literature will introduce the advances and challenge facing exosomes as drug delivery systems, such as exosome isolation, drug loading and targeting therapy application, with the expectation of better delivering new ideas for the development of exosomal drug delivery systems.
Exosomes, widely existing in various biological fluids, are one type of extracellular vesicles secreted by cells and one of carriers of cell-cell communication. The functional materials carried by exosomes, such as nucleic acids, proteins and lipids, are considered as biomarkers for animal physiological diagnosis and as communication carriers for animal physiological states regulation or diseases treatment. Exosomes have been extensively studied as their great development potential. The establishment of mature, stable, convenient and fast exosome isolation methods is a prerequisite for ensuring the smooth progress of exosome related research. Summarized current main methods of animal exosome isolation and compared the characteristics of different isolation methods, the following provides methodological and theoretical references for the further development of related technologies and subsequent animal exosome research.
Rhamnolipids have emerged as a very promising alternatives to their chemo-synthetic counterparts, due to their environmental compatibility and the remarkable physicochemical properties. In recent years, rhamnolipids have been intensively studied, aiming to large-scale improve the production of rhamnolipids based on low-cost renewable resources. However, the current findings are insufficient to screen over-producing rhamnolipids strains with competitive commercial values. Therefore, it is imperative to in-depth understand the sophisticated gene regulatory network of rhamnolipids biosynthesis and explore the fermentation technology to lower the costs. The biosynthetic pathways and the main gene regulatory factors by quorum sensing involved in rhamnolipids production within Pseudomonas aeruginosa are presented, followed by the role of in biofilm formation, and the effect of fermentation optimization on rhamnolipids yield. It is helpful to enhance our understanding on rhamnolipids biosynthesis and provide important reference information for improving the yield of rhamnolipids.
Fungal aromatic polyketides are a class of natural products with a wide range of bio-activite,which catalyzed by fungal non-reducing polyketide synthase (NR-PKSs).Some aromatic polyketide producting strains have problems such as difficulty in cultivation, pathogenicity, or low yield, which fundamentally limit the development and application of fungal aromatic polyketides.With the development of synthetic biology and metabolic engineering, more and more polyketides with biological activity have realized the heterogeneous production of industrial microorganisms(such as Saccharomyces cerevisiae and Aspergillus nidulans,etc.), and related research have gradually become hot spots. The research progress of the synthetic biology of fungal aromatic polyketides in recent years is reviewed from the analysis and mining of biosynthetic pathways, the construction and optimization of chassis cells, etc., which lays the foundation for the efficient synthesis of artificial metabolic pathways of aromatic polyketides and industrial production in the future.
Phenyllactic acid is a new biological preservative which is naturally nontoxic and has broad-spectrum bacteriostatic effect. It can be produced by a variety of different microorganisms, including most lactic acid bacteria. Phenyllactic acid is widely used, which can not only be used in food industry to inhibit a variety of pathogens, but also in medicine and chemical industry. The characteristics, applications and biosynthesis of phenyllactic acid were reviewed, in order to have a systematic understanding of phenyllactic acid and its biosynthesis.
Biobutanol has recently attracted considerable attentions as an important commodity chemical and alternative for petroleum-based fuels. Engineered butanol synthesis pathway has been introduced into E.coli, which is an excellent chassis strain for biosynthetic chemicals. However, the produce of butanol has often been limited by the problems as follows: (1) Non-optimal metabolic flux; (2) Imbalanced CoA and reducing power; (3) Low butanol yields and titer and other issues. Herein, recent advances in butanol biosynthesis of E.coli are summarized and prospected, including screening for high-efficient enzymes, optimization of carbon flux towards butanol, adjusting cofactor supply and optimization of fermentation strategies, which would provide a theoretical basis for high-efficient production of butanol.
Yarrowia lipolytica is an unconventional yeast with the ability to produce a variety of products using diversified substrates. It can survive in diverse environment and is easy to cultivation. It is generally regarded as safe. Y. lipolytica was considered as a new biotechnological strain that has attracted increasing attentions in the scientific research field. In recent years, an emerging industrial technology, industrial biotechnology has developed rapidly worldwide due to its advantages of green, recycling and low carbon. The characteristics of the Y. lipolytica, as well its application in producing high-value compounds were reviewed. Meanwhile, the characteristics and research status of industrial biotechnology were described and the difference between industrial biotechnology and traditional chemical technology was listed. Finally, the application prospect of industrial biotechnology in Y. lipoiytica was discussed.
Represented by the biomedical industry, the bio-industry is leading a new wave of technological industry revolution since mankind entered the era of bioeconomy. China’s strategic deployment for the biopharmaceutical industry has achieved significant results. However, it still has a large competitive gap compared with the powerhouses of biomedical industry such as the United States. The Porter’s diamond model is employed to construct a conceptual framework for the international competitiveness of the biomedical industry, taking the United States as an example to analyze its biomedical industry from six perspectives:(1)Factor conditions;(2) Enterprise structure and competition;(3) Demand conditions;(4)Related and supporting industries;(5)The role of government;(6) Development opportunities. Finally, related policy recommendations for China’s biomedical industry development are put forward,so as to provide policy reference for the development of China’s biomedical industry.
Scientific and technological progress has significantly improved human abilities to control natural biological hazards. While inducing new forms of biological hazards, it has also contributed to the untraceability of biosecurity objects, the diversity of biosecurity subjects and the complexity of evolutionary mechanism of biosecurity hazards. To a large extent, biosecurity is characterized by those non-conventional features of non-traditional security issues. As biotechnology and biosecurity have been playing an increasingly significant role in promoting the continuing development of human community, the 21st century will usher in the age of biosecurity. A new round of biotechnological advances and the ensuing biosecurity issues have gradually infiltrated into the security conceptions of human beings and directly tied to the endogenous crises or challenges faced by modern civilization. To comprehensively upgrade and optimize the biosecurity capabilities and governance is not only a strategic choice for countries all around the world but also a new exploration effort made not only in the scientific and technological field but also on the political arena.
