Partitioning and purification of extracellular β-1,3-1,4-glucanase in aqueous two-phase systems

INTRODUCTION β-1,3-1,4-glucan is the major cell wall compo-nent of barley and other cereal endosperms. It consistsof a polymer of glucose monomers joined by β-1,3-and β-1,4-glycosidic bonds in an irregular fashion(Woodward et al., 1983; Edney et al., 1991). Due toits unique structure, barley β-glucan can be dissolvedin water in high molecular mass and resulting in ahigh viscosity solution. The high-molecular-massβ-glucan released during mashing causes severe fil-tration problems and…     

A food-grade industrial arming yeast expressing β-1,3-1,4-glucanase with enhanced thermal stability

The aim of this work was to construct a novel food-grade industrial arming yeast displaying β-1,3-1,4-glucanase and to evaluate the thermal stability of the glucanase for practical application. For this purpose, a bi-directional vector containing galactokinase (GAL1) and phosphoglycerate kinase 1 (PGK1) promoters in different orientations was constructed. The β-1,3-1,4-glucanase gene from Bacillus subtilis was fused to α-agglutinin and expressed under the control of the GAL1 promoter. α-galactosidase induced by the constitutive PGK1 promoter was used as a food-grade selection marker. The feasibility of the α-galactosidase marker was confirmed by the growth of transformants harboring the constructed vector on a medium containing melibiose as a sole carbon source, and by the clear halo around the transformants in Congo-red plates owing to the expression of β-1,3-1,4-glucanase. The analysis of β-1,3-1,4-glucanase activity in cell pellets and in the supernatant of the recombinant yeast strain revealed that β-1,3-1,4-glucanase was successfully displayed on the cell surface of the yeast. The displayed β-1,3-1,4-glucanase activity in the recombinant yeast cells increased immediately after the addition of galactose and reached 45.1 U/ml after 32-h induction. The thermal stability of β-1,3-1,4-glucanase displayed in the recombinant yeast cells was enhanced compared with the free enzyme. These results suggest that the constructed food-grade yeast has the potential to improve the brewing properties of beer.     

Optimization of cultural conditions for thermostable β-1,3-1,4-glucanase production by Bacillus subtilis ZJF-1A5

INTRODUCTIONβ 1 ,3 1 ,4 glucanisthemajorcellwallcom ponentofbarleyandothercerealendosperm ,andconsistsofpolymersofglucosemonomersjoinedbyβ 1 ,3 andβ 1 ,4glycosidicbondsinanon regularfashion (Woodwardetal.,1 983 ;Edneyetal.,1 991 ) .High molecular mas…     

1,4-二氢吡啶衍生物与DNA相互作用的荧光光谱研究

用荧光光谱研究了1,4-二氢吡啶衍生物(1,4-DHP)与小牛胸腺DNA(CT-DNA)的相互作用。结果表明,1,4-DHP衍生物分子与CT-DNA相互作用后,如其荧光显著增强,表明1,4-DHP衍生物分子嵌入到CT-DNA中,如荧光明显减弱,表明1,4-DHP衍生物分子不是以嵌入模式与CT-DNA相互作用。     

(E)-2-(1,3-二硫戊环-2-亚基)-3-羰基-5-芳基-4-戊烯酸酯的合成

成功地实现了对酸敏感的（E）-2-（1，3-二硫戊环-2-亚基）-3-羰基-5-芳基4-戊烯酸1与脂肪醇的酯化反应，以较好的产率生成相应的酯3．