Understanding the Molecular Mechanisms of Polyphenol Inhibition of Amyloid β Aggregation.

Alzheimer's disease (AD) is highly associated with self-aggregation of amyloid β (Aβ) proteins into fibrils. Inhibition of Aβ aggregation by polyphenols is one of the major therapeutic strategies for AD. Among them, four polyphenols (brazilin, resveratrol, hematoxylin, and rosmarinic acid) have been reported to be effective at inhibiting Aβ aggregation, but the inhibition mechanisms are still unclear.

Hematoxylin modulates tau-RD protein fibrillization and ameliorates Alzheimer's disease-like symptoms in a yeast model.

Alzheimer's disease (AD) is one of the most serious neurodegenerative diseases with no effective treatment options available. The formation of insoluble amyloid fibrils of the hyperphosphorylated tau protein is intimately associated with AD, hence the tau protein has been a key target for AD drug development. In this work, hematoxylin was discovered as a dual functional compound, that is, acting in the inhibition of repeat domain of tau (tau-RD) protein fibrillogenesis and remodeling of pre-formed tau-RD fibrils in vitro.

γ-glutamyl transferase-to-platelet ratio based nomogram predicting overall survival of gallbladder carcinoma.

Background: Gallbladder carcinoma (GBC) carries a poor prognosis and requires a prediction method. Gamma-glutamyl transferase-to-platelet ratio (GPR) is a recently reported cancer prognostic factor. Although the mechanism for the relationship between GPR and poor cancer prognosis remains unclear, studies have demonstrated the clinical effect of both gamma-glutamyl transferase and platelet count on GBC and related gallbladder diseases.

Toward bidirectional photoswitchable colored photochromic molecules with visible light stability.

Photochromic [2]rotaxanes with bidirectional photoswitchability were fabricated, whose colored states exhibit remarkable visible-light and thermal stabilities as revealed by systematically spectroscopic investigations.

Improvement of carbonyl reductase activity for the bioproduction of tert-butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate.

tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is a key chiral intermediate for the side chain synthesis of rosuvastatin. In this study, random mutagenesis, site-saturation mutagenesis and combinatorial mutagenesis methods were applied to improve the activity of a synthesized stereoselective short chain carbonyl reductase (SCR) to prepare (3R,5S)-CDHH. After screened by high-throughput screening method and high-performance liquid chromatography, mut-Phe145Met/Thr152Ser and mut-Phe145Tyr/Thr152Ser, were obtained, and the enzyme activities of mutants were improved by 1.

Enzymatic synthesis of an ezetimibe intermediate using carbonyl reductase coupled with glucose dehydrogenase in an aqueous-organic solvent system.

(4S)-3-[(5S)-5-(4-Fluorophenyl)-5-hydroxypentanoyl]-4-phenyl-1,3-oxazolidin-2-one ((S)-ET-5) is an important chiral intermediate in the synthesis of chiral side chain of ezetimibe. Recombinant Escherichia coli expressing carbonyl reductase (CBR) was successfully constructed in this study. The total E.

Recent advances in biotechnological applications of alcohol dehydrogenases.

Alcohol dehydrogenases (ADHs), which belong to the oxidoreductase superfamily, catalyze the interconversion between alcohols and aldehydes or ketones with high stereoselectivity under mild conditions. ADHs are widely employed as biocatalysts for the dynamic kinetic resolution of racemic substrates and for the preparation of enantiomerically pure chemicals. This review provides an overview of biotechnological applications for ADHs in the production of chiral pharmaceuticals and fine chemicals.

Metabolic engineering of Escherichia coli for microbial production of L-methionine.

L-methionine has attracted a great deal of attention for its nutritional, pharmaceutical, and clinical applications. In this study, Escherichia coli W3110 was engineered via deletion of a negative transcriptional regulator MetJ and over-expression of homoserine O-succinyltransferase MetA together with efflux transporter YjeH, resulting in L-methionine overproduction which is up to 413.16 mg/L.

[Effects of perfluorooctane sulfonate (PFOS) exposure on vitellogenin mRNA level in zebrafish (Brachydanio rerio)].

To study the endocrine disrupting effects and action mechanism of environmental levels of perfluorooctane sulfonate (PFOS) on the aquatic species, the research for the effects of PFOS exposure on vitellogenin (VTG) mRNA level in livers of zebrafish (Brachydanio rerio) was conducted. Zebrafish were exposed to PFOS at four environmental low concentrations (0.1, 1, 10, 100 microg x L(-1)) for 21 days.

Evaluation of the Daphnia magna reproduction test for detecting endocrine disruptors.

The Daphnia 21 d reproduction test is considered as a comprehensive and decisive test in the OECD Conceptual Framework for testing and assessment of endocrine disrupting chemicals (EDCs). However, how to interpret results of the Daphnia 21 d reproduction test for identification, risk assessment and testing strategy of EDCs remains an unsolved issue. This study analysed a total number of 135 published studies encompassing 86 known EDCs and non-EDCs with different modes of action.