[Biosynthesis and regulatory mechanism of acarbose and its structural analogs: a review].

Acarbose is widely used as α-glucosidase inhibitor in the treatment of type Ⅱ diabetes. Actinoplanes sp. is used for industrial production of acarbose. As a secondary metabolite, the biosynthesis of acarbose is quite complex. In addition to acarbose, a few acarbose structural analogs are also accumulated in the culture broth of Actinoplanes sp., which are hard to remove. Due to lack of systemic understanding of the biosynthesis and regulation mechanisms of acarbose and its structural analogs, it is difficult to eliminate or reduce the biosynthesis of the structural analogs. Recently, the advances in omics technologies and molecular biology have facilitated the investigations of biosynthesis and regulatory mechanisms of acarbose and its structural analogs in Actinoplanes sp.. The genes involved in the biosynthesis of acarbose and its structural analogs and their regulatory mechanism have been extensively explored by using bioinformatics analysis, genetic manipulation and enzymatic characterization, which is summarized in this review.

[Research progress in spore-based in-situ restoration technology of concrete with microorganisms].

Concrete is the most widely used modern building material. It is easy to crack under the action of stress, which makes the concrete structure permeable, affecting the durability and integrity of the structure, and thus shortening its service life. Microbial in-situ remediation technology is a low cost, effective and green way for concrete crack repairing. Due to its excellent biocompatibility, service life elongation, economic losses and environmental pollution reduction, microbial in-situ remediation technology has been intensively investigated. Bacillus has attracted much attention because of its excellent biomineralization ability, extremely strong environmental tolerance and long-term survival ability of its spores. In order to promote the research, development and large-scale application of microbial in-situ healing of concrete, the paper reviews the mechanism of spore-based in-situ healing of concrete, the survival of spores exposed in concrete, the influence of spores and external additives on the mechanical properties of concrete, progress in research and development of healing agent as well as healing effects. Moreover, future research focuses such as improving the survival ability of spores in the harsh environment of concrete, reducing the influence of external additives on the mechanical properties of concrete, and strengthening the healing effect of actual field applications are also summarized.