Advances in regulating vitamin K production through metabolic engineering strategies.

Vitamin K (menaquinone, VK, MK) is an essential lipid-soluble vitamin that plays critical roles in inhibiting cell ferroptosis, improving blood clotting, and preventing osteoporosis. The increased global demand for VK has inspired interest in novel production strategies. In this review, various novel metabolic regulation strategies, including static and dynamic metabolic regulation, are summarized and discussed.

Response of salt stress resistance in highland barley (Hordeum vulgare L. var. nudum) through phenylpropane metabolic pathway.

Highland barley (Hordeum vulgare L. var. nudum) is a grain crop that grows on the plateau under poor and high salt conditions.

Enhanced vitamin K2 production by engineered Bacillus subtilis during leakage fermentation.

Menaquinone-7 (MK-7), a valuable member of the vitamin K2 series, is an essential nutrient for humans. It is used for treating coagulation disorders, and osteoporosis, promoting liver function recovery, and preventing cardiovascular diseases. In this study, to further improve the metabolic synthesis of MK-7 by the mutant strain, the effect of surfactants on the metabolic synthesis of MK-7 by the mutant strain Bacillus subtilis 168 KO-SinR (BS168 KO-SinR) was analyzed.

Enantioconvergent hydrolysis of racemic 1,2-epoxypentane and 1,2-epoxyhexane by an engineered Escherichia coli strain overexpressing a novel Streptomyces fradiae epoxide hydrolase.

In order to excavate microbial epoxide hydrolases (EHs) with desired catalytic properties, a novel EH, SfEH1, was identified based on the genome annotation of Streptomyces fradiae and sequence alignment analysis with local protein library. The SfEH1-encoding gene, sfeh1, was then cloned and over-expressed in soluble form in Escherichia coli/BL21(DE3). The optimal temperature and pH of recombinant SfEH1 (reSfEH1) and reSfEH1-expressing E.

Poly-γ-Glutamic Acid Production by Engineering a DegU Quorum-Sensing Circuit in .

As a natural biological macromolecule, γ-polyglutamic acid (γ-PGA) plays a significant role in medicine, food, and cosmetic industries owing to its unique properties of biocompatibility, biodegradability, water solubility, and viscosity. Although many strategies have been adopted to increase the yield of γ-PGA in , the effectiveness of these common approaches is not high because the strong viscosity affects cell growth. However, dynamic regulation based on quorum sensing (QS) has been extensively applied as a fundamental tool for fine-tuning gene expression in reaction to changes in cell density without adding expensive inducers.

Site-directed mutagenesis of the quorum-sensing transcriptional regulator SinR affects the biosynthesis of menaquinone in Bacillus subtilis.

Background: Menaquinone (MK-7) is a highly valuable vitamin K produced by Bacillus subtilis. Common static metabolic engineering approaches for promoting the production of MK-7 have been studied previously. However, these approaches caused an accumulation of toxic substances and reduced product yield.

Identification of six important amino acid residues of MenA from Bacillus subtilis natto for enzyme activity and formation of menaquinone.

The enzyme 1, 4-dihydroxy-2-naphthoic acid (DHNA) prenyltransferase (MenA) is a critical player in determining the efficiency of the menaquinone (MK) synthesis pathway and is an attractive target for the development of novel chemotherapeutics against pathogenic Gram-positive bacteria. However, there has been no report on structural properties or active region of MenA. To solve this challenge, we predicted the three-dimensiona structure and critical amino acid sites of MenA by bioinformatics analysis.

Three New Isoflavonoid Glycosides from the Mangrove-Derived Actinomycete 110B.

The mangrove ecosystem is a rich resource for the discovery of actinomycetes with potential applications in pharmaceutical science. Besides the genus , is also a source of new bioactive agents. We screened from the rhizosphere soil of mangrove plants in Fujian province, China, and 51 strains were obtained.

Two new sixteen-membered macrolides from the genetically engineered strain MHJ1011.

Two new sixteen-membered macrolides, Δ-tenvermectin A () and 13-hydroxy milbemycin (), were isolated from the fermentation broth of the genetically engineered strain MHJ1011. Their structures were determined based on extensive spectroscopic analysis and comparison with related known compounds. Compounds and exhibited potent acaricidal activity against .

A new -cinnamoyl threonine derivative from gene overexpression strain sp. HS-NF-1222A.

A new -cinnamoyl threonine derivative, -(2-(3-methyloxiranyl) cinnamoyl) threonine (), was isolated from the gene overexpression strain sp. HS-NF-1222A. The structure of was determined based on HRESIMS and extensive NMR analysis.

Two new glutarimide antibiotics from Streptomyces sp. HS-NF-780.

Two new glutarimide antibiotics, 9-methylstreptimidone 2-α-D-glucopyranoside (1), and hydroxyiso-9-methylstreptimidone (2), along with a known compound, 9-methylstreptimidone (3), have been isolated from the broth of Streptomyces sp. HS-NF-780. Their structures were determined on the basis of spectroscopic analysis, including 1D and 2D NMR techniques as well as ESI-MS and comparison with data from the literature.

Breeding of Methanol-Tolerant Methylobacterium extorquens AM1 by Atmospheric and Room Temperature Plasma Mutagenesis Combined With Adaptive Laboratory Evolution.

Methylobacterium extorquens AM1, which can be used as a methylotrophic cell factory (MeCF) for the production of fine chemicals from methanol, is the most extensively studied model methylotrophic strain. However, its low tolerance for methanol limits the development of bioprocesses and there have been no reports of improved methanol tolerance of M. extorquens AM1.

Bioconversion of farnesol and 1,4-dihydroxy-2-naphthoate to menaquinone by an immobilized whole-cell biocatalyst using engineered Elizabethkingia meningoseptica.

Menaquinone (MK) has important applications in the pharmaceutical and food industries. To increase the production rate (Q) of MK-4, we developed a straightforward biotransformation method for MK-4 synthesis directly from its precursors 1,4-dihydroxy-2-naphthoate (DHNA) and farnesol using whole cells of genetically engineered Elizabethkingia meningoseptica. Results showed that MK-4 can be produced directly from farnesol and DHNA using both free and immobilized FM-D198 cells.

The change of the state of cell membrane can enhance the synthesis of menaquinone in Escherichia coli.

Menaquinone (MK) was an attractive membrane-bound intracellular chemical. To enhance its production, we tried to find the relationship between its synthesis and the state of cell membrane in producing strain. Due to non-ionic surfactant-polyoxyethylene oleyl ether (POE) and plant oil-cedar wood oil (CWO) can typically increase extracellular secretion and intracellular synthesis of MK respectively, the effect of these two substances on cell morphology, physical properties of cell membrane was investigated.

A high-throughput screening strategy for accurate quantification of menaquinone based on fluorescence-activated cell sorting.

To enhance the screening efficiency and accuracy of a high-yield menaquinone (vitamin K2, MK) bacterial strain, a novel, quantitative method by fluorescence-activated cell sorting (FACS) was developed. The staining technique was optimized to maximize the differences in fluorescence signals between spontaneous and MK-accumulating cells. The fluorescence carrier rhodamine 123 (Rh123), with its ability to reflect membrane potential, proved to be an appropriate fluorescent dye to connect the MK content with fluorescence signal quantitatively.

Governor vessel moxibustion: Ancient Chinese medical technology with new vitality.

Moxibustion is an ancient therapeutic technique used in Chinese medicine. Governor Vessel moxibustion (GVM) was developed from long snake moxibustion, a popular technique used in China's Jiangsu and Zhejiang Provinces, and is significantly more effective than general moxibustion. We aimed to review GVM, including its theoretical basis, choices of moxibustion points and materials, operation procedures, clinical applications, and contraindications.