Daptomycin production enhancement by ARTP mutagenesis and fermentation optimization in Streptomyces roseosporus.

Aims: We evaluated whether the randomness of mutation breeding can be regulated through a double-reporter system. We hope that by establishing a new precursor feeding strategy, the production capacity of industrial microorganisms after pilot scale-up can be further improved.

Methods And Results: In this study, the industrial strain Streptomyces roseosporus L2796 was used as the starter strain for daptomycin production, and a double-reporter system with the kanamycin resistance gene Neo and the chromogenic gene gusA was constructed to screen for high-yield strain L2201 through atmospheric and room temperature plasma (ARTP).

Identification and Characterization of a New Regulator, TagR, for Environmental Stress Resistance Based on the DNA Methylome of Streptomyces roseosporus.

DNA methylation is a defense that microorganisms use against extreme environmental stress, and improving resistance against environmental stress is essential for industrial actinomycetes. However, research on strain optimization utilizing DNA methylation for breakthroughs is rare. Based on DNA methylome analysis and KEGG pathway assignment in Streptomyces roseosporus, we discovered an environmental stress resistance regulator, TagR.

Degradation mechanism of AtrA mediated by ClpXP and its application in daptomycin production in Streptomyces roseosporus.

The efficiency of drug biosynthesis depends on different transcriptional regulatory pathways in Streptomyces, and the protein degradation system adds another layer of complexity to the regulatory processes. AtrA, a transcriptional regulator in the A-factor regulatory cascade, stimulates the production of daptomycin by binding to the dptE promoter in Streptomyces roseosporus. Using pull-down assays, bacterial two-hybrid system and knockout verification, we demonstrated that AtrA is a substrate for ClpP protease.

m4C DNA methylation regulates biosynthesis of daptomycin in L30.

Despite numerous studies on transcriptional level regulation by single genes in drug producing , the global regulation based on epigenetic modification is not well explored. N4-methylcytosine (m4C), an abundant epigenetic marker in ' genome, but its regulatory mechanism remains unclear. In this study, we identify a m4C methyltransferase (SroLm3) in L30 and multi-omics studies were performed and revealed SroLm3 as a global regulator of secondary metabolism.

Improving the Yield and Quality of Daptomycin in by Multilevel Metabolic Engineering.

Daptomycin is a cyclic lipopeptide antibiotic with a significant antibacterial action against antibiotic-resistant Gram-positive bacteria. Despite numerous attempts to enhance daptomycin yield throughout the years, the production remains unsatisfactory. This study reports the application of multilevel metabolic engineering strategies in to reconstruct high-quality daptomycin overproducing strain L2797-VHb, including precursor engineering (i.

Trimetazidine offers myocardial protection in elderly coronary artery disease patients undergoing non-cardiac surgery: a randomized, double-blind, placebo-controlled trial.

Background: Trimetazidine (TMZ) pretreatment protects cardiomyocytes during cardiac surgery. TMZ may protect elderly patients with ischaemic heart disease (IHD) undergoing non-cardiac surgery.

Methods: This was a randomized, double-blind, placebo-controlled trial (registration #ChiCTR1900025018) of patients with IHD scheduled to undergo non-cardiac surgery at Shenzhen People's Hospital (Shenzhen, Guangdong Province, China) between June 2014 and September 2015, randomized to 60 mg TMZ or placebo 12 h before surgery.

OVOL2 inhibits macrophage M2 polarization by regulating IL-10 transcription, and thus inhibits the tumor metastasis by modulating the tumor microenvironment.

Invasion and metastasis of breast cancer cells is an important cause of death in breast cancer patients. In the tumor microenvironment, M2 polarization of macrophages can promote the invasion and metastasis of tumor cells. OVOL2 is an evolutionarily conserved transcription regulator, but its effect in macrophages has not been described previously.

Etomidate propofol in coronary heart disease patients undergoing major noncardiac surgery: A randomized clinical trial.

Background: The ideal depth of general anesthesia should achieve the required levels of hypnosis, analgesia, and muscle relaxation while minimizing physiologic responses to awareness. The choice of anesthetic strategy in patients with coronary heart disease (CHD) undergoing major noncardiac surgery is becoming an increasingly important issue as the population ages. This is because general anesthesia is associated with a risk of perioperative cardiac complications and death, and this risk is much higher in people with CHD.

Berberine protects rat heart from ischemia/reperfusion injury via activating JAK2/STAT3 signaling and attenuating endoplasmic reticulum stress.

Aim: Berberine (BBR), an isoquinoline-derived alkaloid isolated from Rhizoma coptidis, exerts cardioprotective effects. Because endoplasmic reticulum (ER) stress plays a pivotal role in myocardial ischemia/reperfusion (MI/R)-induced apoptosis, it was interesting to examine whether the protective effects of BBR resulted from modulating ER stress levels during MI/R injury, and to define the signaling mechanisms in this process.

Methods: Male rats were treated with BBR (200 mg · kg(-1) · d(-1), ig) for 2 weeks, and then subjected to MI/R surgery.

Enzymatic regioselective acylation of nucleosides in biomass-derived 2-methyltetrahydrofuran: kinetic study and enzyme substrate recognition.

Enzymatic regioselective acylation of pyrimidine nucleosides was mediated by immobilized lipase from Penicillium expansum in 2-methyltetrahydrofuran (MeTHF), a bio-solvent derived from biomass. Despite of the moderate dissolution ability of MeTHF toward nucleosides, the initial enzymatic reaction rate was much higher in this eco-friendly solvent than in other commonly used organic solvents. This could be explained by the lower apparent activation energy of the enzymatic reaction (24.

Regioselective enzymatic undecylenoylation of 8-chloroadenosine and its analogs with biomass-based 2-methyltetrahydrofuran as solvent.

2-Methyltetrahydrofuran (MeTHF), a biomass-derived compound, is a promising medium for biocatalysis and organometallic reactions. The regioselective acylation of 8-chloroadenosine (8-Cl-Ado) and its analogs was carried out in MeTHF with immobilized Penicillium expansum lipase. The lipase displayed more than twofold higher catalytic activity and much better thermostability in MeTHF than in other organic solvents and co-solvent systems.

Highly regioselective synthesis of undecylenic acid esters of purine nucleosides catalyzed by Candida antarctica lipase B.

Regioselective undecylenoylation of purine nucleosides as potential dual prodrugs was achieved by Candida antarctica lipase B using adenosine as a model reactant. The optimum organic solvent, molar ratio of vinyl ester to nucleoside, enzyme dosage, reaction temperature and molecular sieve amount were anhydrous THF, 5:1, 20 U/ml, 45°C and 75 mg/ml, respectively. Under the optimum conditions, the initial reaction rate, yield and 5'-regioselectivity were 1.