Engineering of a fungal steroid 11α-hydroxylase and construction of recombinant yeast for improved production of 11α-hydroxyprogesterone.

Cytochrome P450 enzyme CYP68J5 from filamentous fungus Aspergillus ochraceus is industrially used for selective C11α-hydroxylation of canrenone and progesterone. To improve its selectivity of C11α-hydroxylation for relevant steroid substrates, a sequence-based targeted mutagenesis combined with saturation mutagenesis was conducted to search for variants with improved hydroxylation reaction specificity toward progesterone and D-ethylgonendione. Recombinant yeast expressing triple mutant V64F/E65G/N66T showed significantly increased C11α-hydroxylation selectivity (85 % VS WT 69.

Whole-Cell Biosensor and Producer Co-cultivation-Based Microfludic Platform for Screening with Hyper Erythromycin Production.

Actinomycetes are versatile secondary metabolite producers with great application potential in industries. However, industrial strain engineering has long been limited by the inefficient and labor-consuming plate/flask-based screening process, resulting in an urgent need for product-driven high-throughput screening methods for actinomycetes. Here, we combine a whole-cell biosensor and microfluidic platform to establish the hole-cl biosensor and producer -cultivation-based icrofluidic platform for screning actinomycetes (WELCOME).

New Cytotoxic Cytochalasans from a Plant-Associated Fungus kz-19.

Four new cytochalasans, phychaetoglobins A-D (-), together with twelve known cytochalasans (-), were isolated from a mangrove-associated fungus kz-19. The new structures were elucidated on the basis of extensive 1D and 2D NMR, HR ESIMS spectroscopic analyses, and electronic circular dichroism (ECD) calculations. The absolute configuration of was established by application of Mosher's method.

Droplet-based microfluidic platform for high-throughput screening of Streptomyces.

Streptomyces are one of the most important industrial microorganisms for the production of proteins and small-molecule drugs. Previously reported flow cytometry-based screening methods can only screen spores or protoplasts released from mycelium, which do not represent the filamentous stationary phase Streptomyces used in industrial cultivation. Here we show a droplet-based microfluidic platform to facilitate more relevant, reliable and rapid screening of Streptomyces mycelium, and achieved an enrichment ratio of up to 334.

Antisense RNA Interference-Enhanced CRISPR/Cas9 Base Editing Method for Improving Base Editing Efficiency in 66.

CRISPR/Cas9-mediated base editors, based on cytidine deaminase or adenosine deaminase, are emerging genetic technologies that facilitate genomic manipulation in many organisms. Since base editing is free from DNA double-strand breaks (DSBs), it has certain advantages, such as a lower toxicity, compared to the traditional DSB-based genome engineering technologies. In terms of , a base editing method has been successfully applied in several model and non-model species, such as and .

[Directed evolution of tyrosine ammonia-lyase to improve the production of p-coumaric acid in Escherichia coli].

p-coumaric acid is an important natural phenolic compound with a variety of pharmacological activities, and also a precursor for the biosynthesis of many natural compounds. It is widely used in foods, cosmetics and medicines. Compared with the chemical synthesis and plant extraction, microbial production of p-coumaric acid has many advantages, such as energy saving and emission reduction.

[Rapid generation of double-layer emulsion droplets based on microfluidic chip].

In vitro compartmentalization (IVC) links genotype and phenotype by compartmentalizing individual genes (including expression system) or cells into a micro-droplet reaction region. Combined with fluorescence-activated cell sorting (FACS), it can detect and separate single droplets in ultra-high throughput. IVC-FACS screening method has been widely used in protein engineering, enzyme directed evolution, etc.

[Rapid determination of six banned fragrance components in tea by QuEChERS-gas chromatography-tandem mass spectrometry].

QuEChERS purification was established as a sample pretreatment method and combined with gas chromatography-tandem mass spectrometry (GC-MS/MS) for the simultaneous detection of six banned fragrance components in tea (coumarin, thujone, 2-exylthiophene, -beta-acacene, -mentha-1,8(10)diene-9-ethyl acetate, and butyl cinnamate). Tea samples were extracted with ethyl acetate and subjected to whirlpool oscillation, following which anhydrous magnesium sulfate, primary secondary amine (PSA), and octadecylsilyl silica gel (C18) were added to the supernatant. After centrifugation, the supernatant was filtered over a membrane and separated on a DB-5MS column.

Cytotoxic Withanolides from the Whole Herb of L.

L. is a medicinal plant of the Solanaceae family, which is used to produce a variety of steroids. The present study reports on the cytotoxic withanolides of this plant.

In situ fabrication of two-dimensional g-CN/BaTaO nanosheet heterostructures with efficient charge separations and photocatalytic hydrogen evolution under visible light illumination.

Separation of photo-generated electron-hole pairs plays a crucial role in determining the practical performance of semiconductor photocatalysts. Here we have successfully fabricated two dimensional g-CN/BaTaO nanosheet heterostructures through an in situ urea degradation method. The so-formed nanosheet heterostructures demonstrate superior photocatalytic activities in H evolution reactions over individual component.

[Study of heterologous efficient synthesis of cucurbitadienol].

Cucurbitadienol has anti-inflammation, anti-cancer activities, and acts as a precursor of traditional Chinese medicine active ingredients mogroside and cucurbitacine. For construction of a Sacchromyces cerevisiae cell factory for production of cucurbitadienol, we firstly cloned a cucurbitadienol synthase (CBS) gene from Siraitia grosvenorii. Then, through heterologous expression of CBS in the triterpenoid chassis strain WD-2091, the engineered strain could produced 27.

Biosynthesis and engineering of kaempferol in Saccharomyces cerevisiae.

Background: Kaempferol is a flavonol with broad bioactivity of anti-oxidant, anti-cancer, anti-diabetic, anti-microbial, cardio-protective and anti-asthma. Microbial synthesis of kaempferol is a promising strategy because of the low content in primary plant source.

Methods: In this study, the biosynthesis pathway of kaempferol was constructed in the budding yeast Saccharomyces cerevisiae to produce kaempferol de novo, and several biological measures were taken for high production.

Novel quinoline derivatives as inhibitors of bacterial DNA gyrase and topoisomerase IV.

A structurally novel set of inhibitors of bacterial type II topoisomerases with potent in vitro and in vivo antibacterial activity was developed. Dual-targeting ability, hERG inhibition, and pharmacokinetic properties were also assessed.

Preliminary X-ray diffraction analysis of octaprenyl pyrophosphate synthase from Escherichia coli.

Octaprenyl pyrophosphate synthase (OPPs), which belongs to the E-type prenyltransferase family, catalyses the successive condensation of farnesyl pyrophosphate with five isopentenyl pyrophosphate molecules to form trans-C40-octaprenyl pyrophosphate (OPP). OPP is essential for the biosynthesis of bacterial ubiquinone or menaquinone side chains, which play an important role in the electron-transport system. Here, Escherichia coli OPPs was expressed, purified and crystallized.

2,2-Bis(hy-droxy-meth-yl)-2,3-dihydro-1H-pyrrolizin-1-one.

The title compound, C(9)H(11)NO(3), was prepared by an Aldol reaction of 2,3-dihydro-1H-pyrrolizin-1-one with formaldehyde. The asymmetric unit contains six mol-ecules. The pyrrolizine ring system in each mol-ecule is planar, the maximum atomic deviation being 0.

(E)-2-(2-Furylmethyl-idene)-2,3-dihydro-1H-pyrrolizin-1-one.

The title compound, C(12)H(9)NO(2), was prepared by an Aldol reaction of furfuraldehyde with 2,3-dihydro-1H-pyrrolizin-1-one. The mol-ecule is almost planar, with an r.m.

2,3-Dihydro-1H-pyrrolizin-1-one.

There are two nearly identical mol-ecules in the asymmetric unit of the title compound, C(7)H(7)NO. The mol-ecules are nearly planar (r.m.