Application of methyltransferases in microbial synthesis of natural products / 生物工程学报

Methyltransferases (MTs) constitute a large group of enzymes that catalyze the transfer of a methyl moiety, most frequently from S-adenosyl-L-methionine, to their substrates. It plays an essential role in regulation of gene expression and synthesis of many natural compounds. Owing to its broad substrate spectrum, MTs make important contributions to diversify the spectrum of products through methylation modifications. Recently, great progress has been made in application of MTs for the biosynthesis of various natural products including phenylpropane compounds, fragrances, hormones and antibiotics, which is summarized in this review. Moreover, we highlighted the strategies of using MTs for efficient production and for expanding the diversity of these methylated natural products, and discussed the current challenges and future prospects in this area.

Preface to the special issue: biosynthesis of natural products / 生物工程学报

Natural products, important sources of innovative drugs, food, spices and daily chemicals, are closely related to people's healthy life. With the development and integration of modern biological and chemical technologies of natural products, the researches on biosynthesis of natural products have made great progresses in recent years. The biosynthetic pathways of a number of natural products have been analyzed. Many pathway enzymes and modifying enzymes involved in the biosynthesis of natural products have been mined and functionally characterized. Furthermore, genes encoding pathway enzymes have been introduced into chassis to construct cell factories producing natural products through synthetic biology technologies. Also, other biotechnologies including genome editing and genome mining, have been used in the biosynthesis of natural products. In order to further promote the development of researches on biosynthesis of natural products, we edited a Special Issue on the topic of "biosynthesis of natural products", focusing on the researches progress in three aspects: the analysis of biosynthetic pathways of natural products, genome-wide mining and functional characterization of genes encoding tool enzymes, and the scale preparation of natural products by biosynthetic technology. Also included in this Special Issue was the prospect of the biosynthesis of natural products. This Special Issue can provide reference and guidance for the further development of natural product biosynthesis.

Advances in metabolic engineering of heterotrophic microorganisms for CO₂ fixation: a review / 生物工程学报

Environmental protection and energy supply are our two major concerns. Greenhouse gases released from energy consumption have serious impact on the environment. CO₂ fixation can be used to convert CO₂ into fuels or chemicals. However, natural carbon-fixing organisms usually have some disadvantages such as slow growth and low carbon fixation efficiency. Enhancing or remodeling CO₂ fixation pathways in model microorganisms can realize CO₂ recycling, which can further increase fuel or chemical production and reduce greenhouse gas emission. This review describes in detail metabolic engineering of CO₂ fixation pathways to improve chemical production and sugar synthesis, elaborates the role of relevant metabolic pathways and key enzymes in CO₂ fixation, introduces the application of electro-biochemical synthesis system, shows the great potential of CO₂ fixation, and prospects the future research direction of CO₂ fixation.

Bacteria in super capacitor electrode materials: a review / 生物工程学报

As a major factor in determining performances of the electrochemical super capacitor, electrode materials have received wide attentions recently. Bacteria, with their advantages of low cost, abundance, environmental protection and easy to get from nature, have become the promising biomaterials. The composite electrode materials based on bacteria or their related products, have the advantages of large specific surface area, good cycle stability and high capacitance, and become the research focus in the field of super capacitor electrode materials. Herein, the characteristics and related technology of different bacteria on the preparation of electrode materials for super capacitor were summarized. This review systematically elaborates the latest research progress of bacterial composite electrode materials. Moreover, the prospect of super capacitors has been discussed.

Research progress in chondroitinase ABC / 生物工程学报

As the components of proteoglycans, glycosaminoglycans (GAGs) are linear polysaccharides consisting of hexose and uronic acid units linked by β-1,3-glycosidic bond. GAGs mainly distribute in extracellular matrix and on cell surfaces. They guide many biological processes, such as proliferation of cells, transmission of signals and mediation of inflammation. Because of their large molecular weights, GAGs have limited biological functions in vitro. However, the appearance of chondroitinase ABC (ChSase ABC), which can lyse polysaccharides, solves the difficulties. Based on our work, we summarized the classification and the crystal structure of ChSase ABC, as well as other recent research progress on ChSase ABCs. The separation and purification methods of ChSase ABC and construction of engineering bacteria are illustrated. The stability and immobilization are also analyzed by taking account of the characterization of ChSase ABC. Finally, problems and future prospect of the ChSase ABC study are summarized.

Effect of iontophoresis on skin permeation of defibrase / 药学学报

Aim To investigate the effect of iontophoresis on skin permeation of defibrase. Methods Iontophoresis was carried out in side-by-side chambers, excised rat skin membrane (RSM) or human epidermis membrane (HEM). The effects of electrode polarity, permeation medium pH and ionic strength were evaluated. Results Permeation of defibrase caused by anodal iontophoresis was more effective [the apparent permeability coefficient was (1.2±0.4)×10-4 cm·h-1] than that of cathodal iontophoresis[(4.3±1.4)×10-5 cm·h-1]. The amount of permeated defibrase caused by anodal iontophoresis in pH 7.4 medium was (25±5)×10-14 mol·cm-2, which was higher than that of in pH 6.4 permeation medium [(15±4)×10-14 mol·cm-2]. Conclusion Iontophoresis could enhance skin permeation of defibrase. Electroosmotic flow effect played an important role.

Study on Immobilization Plant Cell Culture and Release of Intracellular Metabolites / 中草药

Membrane immobilization of Catharathus roseus (L. )G. Don cell culture was stuudied. Results showed that the production capacity can attain a higher level when the cell layer was 7~8mm thick. Stainless-steel screen(80?m)was suitable for immobllization of C. roses cell. Pressure pulse can enhance the release of intracelluler metabolites. A method to determine allowable cell layer thickness was developed. The calculated value agreed well with experimental results.

THE BIOSYNTHESIS OF COENZYME Q_(10) IN BULLERA PSEUDOALBA / 微生物学通报

The addition of nature substances such as soybean oil, carrot extract, tomato extract, wastes of tobacco industry and citrus molasses to growth medium was shown to strengthen the formation of Coenzyme Q 10 Some of these substances act as precursors of Coenzyme Q 10 and Beta Carotene, and others such as wastes of tobacco industry and Beta Carotene act as inhibitors of Beta Carotene; they all can strengthen the formation of Coenzyme Q 10 Immediately relationship between the biosynthesis of Coenzyme Q 10 and Beta Carotene has been detected