UPLC-TOF/MS-based metabolomics reveals the chemical changes and in vitro biological effects in fermentation of white ginseng by four probiotics.

Microbial fermentation is a useful method for improving the biological activity of Chinese herbal medicine. Herein, we revealed the effects of solid-state fermentation by Lactiplantibacillus plantarum, Bacillus licheniformis, Saccharomyces cerevisiae, Eurotium cristatum and multiple strains on total flavonoid content, total phenol content, as well as antioxidants, α-amylase inhibitory activities and α-glucosidase inhibitory activities in white ginseng (WG). Metabolite differences between non-fermented and fermented WG by different probiotics were comprehensively investigated using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS). Results showed that the total flavonoid content, ferric reducing antioxidant power, scavenging activities of DPPH radical and ABTS radical, α-amylase inhibitory activities and α-glucosidase inhibitory activities of WG were considerably enhanced after processing by solid-state fermentation in all strains. The total phenol content was increased by E. cristatum and B. licheniformis fermentation, but decreased by L. plantarum, S. cerevisiae and multi-strain fermentation. Additionally, E. cristatum exhibited stronger biotransformation activity on WG compared to other strains. Significant differential metabolites were mainly annotated as prenol lipids, carboxylic acids and derivatives, flavonoids, polyphenols, coumarins and derivatives. Correlation analysis further showed that changes of these metabolites were closely related to antioxidant and hypoglycemic effects. Our results confirmed that fermentation of WG by different probiotics has distinct effects on biological activities and metabolite composition, and indicating fermentation as an important novel strategy to promote components and bioactivities of WG.

An oral hydrogel carrier for delivering resveratrol into intestine-specific target released with high encapsulation efficiency and loading capacity based on structure-selected alginate and pectin.

Resveratrol (RES) has many beneficial effects on the human body, but it is always unstable, resulting in low oral bioavailability, especially in the gastrointestinal tract. In this study, we developed an oral intestine-specific released hydrogel carrier for targeted RES release in the intestinal tract, which was composed of alginate (ALG) with a specific ratio of α-L-guluronic (G blocks) and ß-D-mannuronic (M blocks) and low methoxyl pectin (LMP). The encapsulation efficiency and loading capacity of RES was 92.04 ± 0.32% and 6.41 ± 0.022 mg g-1 samples, respectively. Positioning release kinetics were investigated in vivo and in vitro. Also, this hydrogel carrier provides good protection for RES against the stomach. 94.71% of RES could be transported to the intestines in two hours after oral administration and released mainly in the small intestine and colon. Thus, the hydrogel carrier is conducive to RES, which is absorbed through the intestinal barrier rather than the stomach after oral administration. Moreover, the hydrogel carrier could load other health factors with expected encapsulation efficiencies, such as curcumin (93.52%), ascorbic acid (90.33%), ginsenoside Rg3 (81.54%), and EGCG (92.27%). These also implied that the hydrogel carrier holds general applicability in disease management.

Heterologous biosynthesis of taraxerol by engineered Saccharomyces cerevisiae.

Taraxerol is an oleanane-type pentacyclic triterpenoid compound distributed in many plant species that has good effects on the treatment of inflammation and tumors. However, the taraxerol content in medicinal plants is low, and chemical extraction requires considerable energy and time, so taraxerol production is a problem. It is a promising strategy to produce taraxerol by applying recombinant microorganisms. In this study, a Saccharomyces cerevisiae strain WKde2 was constructed to produce taraxerol with a titer of 1.85 mg·l-1, and the taraxerol titer was further increased to 12.51 mg·l-1 through multiple metabolic engineering strategies. The endoplasmic reticulum (ER) size regulatory factor INO2, which was reported to increase squalene and cytochrome P450-mediated 2,3-oxidosqualene production, was overexpressed in this study, and the resultant strain WTK11 showed a taraxerol titer of 17.35 mg·l-1. Eventually, the highest reported titer of 59.55 mg·l-1 taraxerol was achieved in a 5 l bioreactor. These results will serve as a general strategy for the production of other triterpenoids in yeast.

Biosynthesis of valerenic acid by engineered Saccharomyces cerevisiae.

OBJECTIVE: To produce valerenic acid (VA) in Saccharomyces cerevisiae by engineering a heterologous synthetic pathway. RESULT: Valerena-4,7(11)-diene synthase (VDS) derived from Valeriana officinalis (valerian) was expressed in S. cerevisiae to generate valerena-4,7(11)-diene as the precursor of VA. By overexpressing the key genes of the mevalonate pathway ERG8, ERG12 and ERG19, and integrating 4 copies of MBP (maltose-binding protein)-VDS-ERG20 gene expression caskets into the genome, the production of valerena-4,7(11)-diene was improved to 75 mg/L. On this basis, the cytochrome P450 monooxygenase LsGAO2 derived from Lactuca sativa was expressed to oxidize valerena-4,7(11)-diene to produce VA, and the most effective VA production strain was used for fermentation. The yield of VA reached 2.8 mg/L in the flask and 6.8 mg/L in a 5-L bioreactor fed glucose. CONCLUSIONS: An S. cerevisiae strain was constructed and optimized to produce VA, but the valerena-4,7(11)-diene oxidation by LsGAO2 is still the rate-limiting step for VA synthesis that needs to be further optimized in future studies.

Research progress in bioremediation of petroleum pollution.

With the enhancement of environmental protection awareness, research on the bioremediation of petroleum hydrocarbon environmental pollution has intensified. Bioremediation has received more attention due to its high efficiency, environmentally friendly by-products, and low cost compared with the commonly used physical and chemical restoration methods. In recent years, bacterium engineered by systems biology strategies have achieved biodegrading of many types of petroleum pollutants. Those successful cases show that systems biology has great potential in strengthening petroleum pollutant degradation bacterium and accelerating bioremediation. Systems biology represented by metabolic engineering, enzyme engineering, omics technology, etc., developed rapidly in the twentieth century. Optimizing the metabolic network of petroleum hydrocarbon degrading bacterium could achieve more concise and precise bioremediation by metabolic engineering strategies; biocatalysts with more stable and excellent catalytic activity could accelerate the process of biodegradation by enzyme engineering; omics technology not only could provide more optional components for constructions of engineered bacterium, but also could obtain the structure and composition of the microbial community in polluted environments. Comprehensive microbial community information lays a certain theoretical foundation for the construction of artificial mixed microbial communities for bioremediation of petroleum pollution. This article reviews the application of systems biology in the enforce of petroleum hydrocarbon degradation bacteria and the construction of a hybrid-microbial degradation system. Then the challenges encountered in the process and the application prospects of bioremediation are discussed. Finally, we provide certain guidance for the bioremediation of petroleum hydrocarbon-polluted environment.

Systemic delivery and pre-clinical evaluation of nanoparticles containing antisense oligonucleotides and siRNAs.

By virtue of their potential to selectively silence oncogenic molecules in cancer cells, antisense oligonucleotides (ASO) and small interfering RNAs (siRNAs) are powerful tools for development of tailored anti-cancer drugs. The clinical benefit of ASO/siRNA therapeutic is, however, hampered due to poor pharmacokinetics and biodistribution, and suboptimal suppression of the target in tumor tissues. Raf-1 protein serine/threonine kinase is a druggable signaling molecule in cancer therapy. Our laboratory has developed cationic liposomes for systemic delivery of raf ASO (LErafAON) and raf siRNA (LErafsiRNA) to human tumor xenografts grown in athymic mice. LErafAON is also the first ASO containing liposomal drug tested in humans. In this article, we primarily focus on a modified formulation of systemically delivered cationic liposomes containing raf antisense oligonucleotide (md-LErafAON). The cationic liposomes were prepared using dimyristoyl 1,2-diacyl-3-trimethylammonium-propane (DMTAP), phosphatidylcholine (PC), and cholesterol (CHOL). The toxicology, pharmacokinetics, biodistribution, target selectivity, and anti-tumor efficacy studies of md-LErafAON were conducted in mice. We demonstrate that md-LErafAON is the next generation of systemically delivered and well-tolerated antisense therapeutic suitable for clinical evaluation.