Polysaccharides synthesis, promotion

Promotion of growth of chick embryonic femur and its protein and polysaccharide synthesis in vitro ... 

Wang, X., Preston, J. F., and Romeo, T. (2004). The pgaABCD locus of Escherichia coli promotes the synthesis of a polysaccharide adhesion required for biofilm formation. /. Bacterial. 186, 2724-2734. 

Acid or Lewis-acid catalyzed self-condensation reactions of 1,2-anhydro sugars were studied for the synthesis of polysaccharides [438]. Polysaccharides of relatively low molecular weights (< 10,000) were obtained, and the anomeric configurations could be varied depending on the promoter and temperature [439]. 

The biosynthesis of HS has been the fundamental subject of the HS study field. A detailed view of HS biosynthesis would aid in elucidation of the structure-function relationship of HS in different biological contexts. In addition, a complete grasp of the biosynthesis mechanism would promote the development of the in vitro biosynthesis of HS or HS-like macromolecules for therapeutic purposes. In the past decade, as a result of the sustained effort to understand the biosynthetic pathway of HS, all enzymes involved in HS biosynthesis have been cloned and purified, which greatly advanced our knowledge of this essential biological process. It should be noted that the availability of HS biosynthetic enzymes also provided the opportunity for conducting enzyme-based synthesis of HS polysaccharides... 

Aeration, water-holding capacity, and permeability are all improved by humus. The frequent addition of easily decomposable organic residues leads to the synthesis of complex organics (e.g., polysaccharides) that bind soil particles into aggregates. The intimate association of clay-sized particles (layer silicates) with humus via cation (e.g., calcium, magnesium, aluminum, iron) bridges also promotes aggie-... 

In the carbohydrate area, two important uses of the reagent have appeared one uses NBS-MesSiOTf as the promoter for the glycosidic bond formation and simultaneous bromination of an activated aryl aglycon. In the second, the synthesis of branched polysaccharides by polymerization of 6-0-f-butyldimethylsilyl-D-glucal through stereoregular bromoglycosylation was achieved by the use of NBS. 

The usefulness of dispiroketal to act as practical glycosyl donors was further illustrated in a facile one-pot synthesis of a trisaccharide fragment from the capsular polysaccharide of Group B Streptococci [80]. In the following example (Scheme 29), armed perbenzylated ethyl l-thio-oj-L-rhamnopyranoside donor 157 was treated with semidisarmed dispiroketal 158 under IDCP promoted glycosylation to provide disaccharide 159 in 59% yield. Glycosidation of acceptor 159 with acceptor 160 with the more potent NIS/TfOH couple afforded protected... 

The first synthesis of a cellulose-xylan hybrid polymer, a novel polysaccharide having a glucose-xylose repeating imit, has been achieved by the xylanase-catalyzed polymerization of j8-xylopyranosyl-glucopyranosyl fluoride (Fig. 2) (35, 36). Identification of the enzyme fraction promoting the polymerization showed that endoxylanase was highly efficient for production of the hybrid polymer. 

Indeed examination of many soil bacteria in situ reveals them to be heavily encapsulated. The synthesis of bacterial polysaccharides appears crucial to the maintenance of soil structure and ultimately soil fertility. The coalescence of mineral particles to form aggregates and the resistance of such aggregates to stress is a measure of a soil s stability. Many soil bacteria are able to bind soil particles into aggregates, through the production of extracellular polysaccharides, or by charge interactions. Addition of Azoto-bacter chroococcum or Pseudomonas sp. promotes the stabilisation of sterilised silt loam soils. 

Most phosphorus associated with cereal grains exists in the form of phytic acid (myoinositol hexaphosphate) that is stored in phytic bodies mainly loeated in the aleurone layer. These molecules bind potassium, magnesium, and other minerals. The phytases degrade these compounds to release phosphate, other minerals, and myoinositol. The myoinositol is a known precursor of sugars associated with cell wall polysaccharides and a promoter of seedling growth. The free phosphorus is critically important for synthesis of nucleic acids and phospholipids for cellular membrane proliferation, and ATP and energy production. 

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