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Endo-β-N-acetylglucosaminidases (ENGases) are pivotal enzymes in the degradation and remodeling of glycoproteins, which catalyze the cleavage or formation of β-1,4-glycosidic bond between two N-acetylglucosamine (GlcNAc) residues in N-linked glycan chains. It was investigated that targeted mutations of amino acids in ENGases active site may modulate their hydrolytic and transglycosylation activities. Endo-Tb, the ENGase derived from Trypanosoma brucei, belongs to the glycoside hydrolase family 85 (GH85). Our group previously demonstrated that Endo-Tb exhibits hydrolytic activity toward high-mannose and complex type N-glycans and preliminarily confirmed its transglycosylation potential. In this study, we further optimized the transglycosylation activity of recombinant Endo-Tb by focusing on the N536A, E538A and Y576F mutants. A comparative analysis of their transglycosylation activity with that of the wild-type enzyme revealed that all mutants exhibited enhanced transglycosylation capacity. The N536A mutant exhibited the most pronounced improvement in transglycosylation activity with a significant reduction in hydrolytic activity. It is suggested that Endo-Tb N536A possesses the potential as a tool for synthesizing a wide array of glycoconjugates bearing high-mannose and complex type N-glycans. [ABSTRACT FROM AUTHOR]

Backgrounds and aims: Although a number of studies have been conducted on the association between plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism and diabetic nephropathy (DN) in Chinese population, this association remains elusive and controversial. To further assess the effects of PAI-1 4G/5G polymorphism on the risk of DN, a meta-analysis was performed in the Chinese population. Methods: Relevant studies were identified using PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure, and Chinese Biology Medicine through November, 2015. Pooled odds ratios (ORs) and 95 % confidence intervals (CIs) were used to assess the strength of the associations. Results: This meta-analysis identified nine studies, including 777 DN cases, 413 healthy controls, and 523 DM controls. In the total analyses, a significantly elevated risk of DN was associated with variants of PAI-1 4G/5G when compared with the healthy group (4G vs. 5G, OR 2.46, 95 % CI 1.45-4.16; 4G/4G vs. 5G/5G, OR 4.32, 95 % CI 1.79-10.39; 4G/4G vs. 4G/5G +5G/5G, OR 2.96, 95 % CI 1.59-5.53; 4G/4G +4G/5G vs. 5G/5G, OR 2.78, 95 % CI 1.34-5.75) and DM group (4G vs. 5G, OR 1.93, 95 % CI 1.28-2.92; 4G/4G vs. 5G/5G, OR 2.99, 95 % CI 1.44-6.21; 4G/4G vs. 4G/5G +5G/5G, OR 2.84, 95 % CI 1.77-4.54). In the subgroup analyses stratified by ethnicity and geographic areas, it revealed the significant results in Chinese Han, in North and South China. Conclusions: This meta-analysis showed that the PAI-1 4G/4G variant, 4G allele might be risk alleles for DN susceptibility in the Chinese population, and further studies in other ethic groups are required for definite conclusions. [ABSTRACT FROM AUTHOR]

By analyzing the abrasive theory of concrete diamond sawblade, the proposal that the diamond should be selected by its function in cutting concrete is presented. The part of the big grit diamonds cut rock, and the part of the small grit diamonds improve the wearability of the matrix. The contrast tests are done with different shapes of sawbaldes in split segment, slant “U” slot segment, sandwich segment, turbo segment and three-slot segment. The special shapes of sawblades can improve the effect of cooling and the removing ability of the rock powder. The data of tests show that the efficiency of cutting and the life of sawblades are improved by designing the diamond prescription and using the especial geometry of segment. [ABSTRACT FROM AUTHOR]