Gos-Transglycosylation-Activity-Microorganisms-r
The structure of GOS varies with different enzyme source. The oligosaccharide yields of GOS produced by natural enzymes are generally %-45% and they could be improved by artificial enzyme. Reaction conditions also have effect on the oligosaccharide yield. Using enzymes in water-hydrophobic solvent mixtures or reverse micelles may improve the yield to some extent. GOS can be large-scale synthesized by packed bed reactor, plugflow reactor or membrane reactor. The glucose and lactose in the GOS products can be removed by using chromatography, enzyme oxidation, nanofiltration membrane or microbial fermentation.
Preparation of alginate oligosaccharides and their biological activities in 1134, China; Dalian Engineering Research Center for Carbohydrate Agricultural Preparations, Liaoning Provincial Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 1123, Preparations, Liaoning Provincial Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 1123, Preparations, Liaoning Provincial Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 1123, Alginate oligosaccharide (AOS) is the degradation product of alginates extracted from brown algae. As a multifunctional oligomer, it has attracted widespread attention in plant research. Different methods of preparation generate AOS possessing diverse structural properties, and result in differences in AOS activity. In this review, the methods of preparation and characterization of AOS are briefly summarized, followed by a systematic introduction to the activity and mechanisms of AOS in plants. AOS can act as a growth promoter at different growth stages of plants. AOS also enhances resistance to pathogens, drought, salt, heavy metals and other stressors by triggering plant immunity, exerting bioactivity just like a pathogen-associated molecular pattern. In addition, AOS can regulate ABA biosynthesis and metabolite to preserve fruit quality and enhance shelf life.
This review provides a comprehensive summary of the biological activity of AOS in plants, which will support research and the application of AOS treatments for plants in the future.Conflict of interest statement Declaration of competing interest The authors declare that there is no conflict of interest between them.Automated solid-phase synthesis of protected oligosaccharides containing For automated oligosaccharide synthesis to impact glycobiology, synthetic access to most carbohydrates has to become efficient and routine. Methods to install difficult glycosidic linkages have to be established and incorporated into the overall synthetic concept. Described here is the first automated solid-phase synthesis of oligosaccharides containing the challenging beta-mannosidic linkage. Carboxybenzyl mannoside building blocks proved effective beta-mannosylation agents and resulted in excellent conversion and good to moderate selectivities. [(Triisopropylsilyl)oxy]-methyl ether (Tom), served as an orthogonal, minimally intrusive, and readily cleavable protecting group for the elongation of the C3 position of mannose.
The desired oligosaccharide products were readily separated from by-products containing unwanted stereoisomers using reverse-phase HPLC. The methods described here expand the scope of carbohydrates currently accessible by automation as many oligosaccharides of biological interest contain beta-mannosidic linkages.Synthesis and biological activity of oligosaccharide libraries.Random glycosylation has proven remarkably effective for the generation of mixtures of oligosaccharides. Clearly, not all of the possible glycosidically-linked isomers are formed in equal quantity in these reactions. In the instances where product structures have been thoroughly investigated, however, all have been shown to be present. So far, only 2'-fucosyllactose has been performed and the challenge will be to see if two tandem steps can generate a useful oligosaccharide library.
Whether or Grab it today of random glycosylation succeeds as a dominant strategy for the synthesis of oligosaccharide libraries, this important challenge is open to many approaches where creativity in both formulating the problem, as well as experimentally addressing it, warrants a major international effort.Site-specific glycosylation of secretory immunoglobulin A from human colostrum.
