[Advances in synthesis of 2-phenylethanol].

2-phenylethanol (2-PE), an aromatic alcohol with a rose fragrance, is the second most widely used flavoring substance in the world. It is widely used in the cosmetic, food, and pharmaceutical industries. This paper introduces the chemical synthesis methods of 2-PE and the synthetic pathways in plants and microorganisms, summarizes the strategies to improve the microbial synthesis of 2-PE, reviews the research progress in synthesis of 2-PE in microorganisms, and makes an outlook on the research prospects, aiming to provide a theoretical basis for the industrial production of 2-PE.

De novo biosynthesis of p-coumaric acid and caffeic acid from carboxymethyl-cellulose by microbial co-culture strategy.

Background: Aromatic compounds, such as p-coumaric acid (p-CA) and caffeic acid, are secondary metabolites of various plants, and are widely used in diet and industry for their biological activities. In addition to expensive and unsustainable methods of plant extraction and chemical synthesis, the strategy for heterologous synthesis of aromatic compounds in microorganisms has received much attention. As the most abundant renewable resource in the world, lignocellulose is an economical and environmentally friendly alternative to edible, high-cost carbon sources such as glucose.

High-copy genome integration and stable production of p-coumaric acid via a POT1-mediated strategy in Saccharomyces cerevisiae.

Aims: To overcome the defective unstable production of p-coumaric acid (p-CA) using episomal plasmids and simultaneously achieve genetic stability and high-copy integration in Saccharomyces cerevisiae.

Methods And Results: Two-micron plasmids were used to obtain high titres of p-CA, but p-CA production was decreased significantly in a nonselective medium after 72 h. To overcome the defect of unstable p-CA production during fermentation, delta integration with the triosephosphate isomerase gene from Schizosaccharomyces pombe (POT1) was employed as a selection marker to integrate heterologous p-CA synthesis cassette, and the high-level p-CA-producing strain QT3-20 was identified.

Developing Multi-Copy Chromosomal Integration Strategies for Heterologous Biosynthesis of Caffeic Acid in .

Caffeic acid, a plant-sourced phenolic compound, has a variety of biological activities, such as antioxidant and antimicrobial properties. The caffeic acid biosynthetic pathway was initially constructed in , using codon-optimized (, encoding tyrosine ammonia lyase) from , (encoding -coumaric acid 3-hydroxylase) and (encoding cytochrome P450 reductase 1) from in 2 μ multi-copy plasmids to produce caffeic acid from glucose. Then, integrated expression of delta integration with the gene (encoding triose phosphate isomerase) as selection marker and episomal expression of , using the episomal plasmid pLC-c3 were combined, and caffeic acid production was proved to be improved.

Quantitative Evaluation of Gastrocnemius Medialis Stiffness During Passive Stretching Using Shear Wave Elastography in Patients with Parkinson's Disease: A Prospective Preliminary Study.

Objective: To prospectively investigate the feasibility of shear wave elastography (SWE) as a new quantitative and objective method for evaluating the stiffness of the gastrocnemius medialis (GM) muscle during passive stretching in patients with Parkinson's disease (PD).

Materials And Methods: SWE of the GM muscle was performed in 28 patients with PD [13 female and 15 male; mean age ± standard deviation (SD): 63.0 ± 8.

The Efficacy of Contrast Transthoracic Echocardiography and Contrast Transcranial Doppler for the Detection of Patent Foramen Ovale Related to Cryptogenic Stroke.

Background: Patent foramen ovale (PFO) has been linked to the pathophysiology of cryptogenic stroke. Contrast transesophageal echocardiography (cTEE) is the current gold standard for PFO diagnosis, but it has the disadvantage of being semi-invasive and does not exempt from risks. As a diagnostic test, the efficacy of contrast transthoracic echocardiography (cTTE) and contrast transcranial Doppler (cTCD) is controversial.

Biosynthesis of Caffeic Acid from Glucose by Engineered .

Caffeic acid is a plant phenolic compound possessing extensive pharmacological activities. Here, we identified that -coumaric acid 3-hydroxylase from was capable of hydroxylating -coumaric acid to form caffeic acid in . Then, we introduced a combined caffeic acid biosynthetic pathway into and obtained 0.

Comparative transcriptome analysis of genomic region deletion strain with enhanced L-tyrosine production in Saccharomyces cerevisiae.

Objective: To determine the effect of large genomic region deletion in a Saccharomyces cerevisiae strain on tyrosine yield and to identify new genetic modification targets through transcriptome analysis.

Results: TAL was used to produce p-coumaric acid (p-CA) from tyrosine to quantity tyrosine yield. S.

Metabolic engineering strategies for improvement of ethanol production in cellulolytic Saccharomyces cerevisiae.

As a traditional ethanol-producing microorganism, Saccharomyces cerevisiae is an ideal host for consolidated bioprocessing. However, expression of heterologous cellulase increases the metabolic burden in yeast, which results in low cellulase activity and poor cellulose degradation efficiency. In this study, cellulase-expressing yeast strains that could efficiently degrade different cellulosic substrates were created by optimizing cellulase ratios through a POT1-mediated δ-integration strategy.

A high-throughput method for screening of L-tyrosine high-yield strains by Saccharomyces cerevisiae.

A biosensor screening assay based on the synthesis of betaxanthin was applied to relatively high throughput screening of the L-tyrosine mutant library. In the assays, fluorescence output showed a linear relationship between extracellular L-tyrosine content and yellow pigment formation. In addition, the yellow pigment accumulation of the L-tyrosine high-yield strain can be easily distinguished with the naked eye compared with the wild-type strain.

POT1-mediated δ-integration strategy for high-copy, stable expression of heterologous proteins in Saccharomyces cerevisiae.

In biotechnological industry, increased expression cassette stability and copy number serve as important means of maintaining consistently high production levels of heterologous proteins in Saccharomyces cerevisiae. In this study, we combined δ sequences for site-specific integration with TPI1 gene from Schizosaccharomyces pombe (POT1) as a selection marker to realize high-copy integration and stable expression of heterologous proteins in S. cerevisiae.

Reduced production of ethyl carbamate for wine fermentation by deleting CAR1 in Saccharomyces cerevisiae.

Ethyl carbamate (EC), a pluripotent carcinogen, is mainly formed by a spontaneous chemical reaction of ethanol with urea in wine. The arginine, one of the major amino acids in grape musts, is metabolized by arginase (encoded by CAR1) to ornithine and urea. To reduce the production of urea and EC, an arginase-deficient recombinant strain YZ22 (Δcarl/Δcarl) was constructed from a diploid wine yeast, WY1, by successive deletion of two CAR1 alleles to block the pathway of urea production.