Jung Nam Choi

Microbial community and metabolomic comparison of irritable bowel syndrome faeces

Human health relies on the composition of microbiota in an individual’s gut and the synthesized metabolites that may alter the gut environment. Gut microbiota and faecal metabolites are involved in several gastrointestinal diseases. In this study, 16S rRNA-specific denaturing gradient gel electrophoresis and quantitative PCR analysis showed that the mean similarity of total bacteria was significantly different (P<0.001) in faecal samples from patients with irritable bowel syndrome (IBS; n = 11) and from non-IBS (nIBS) patients (n = 8). IBS subjects had a significantly higher diversity of total bacteria, as measured by the Shannon index (H′) (3.36<H′<4.37, P = 0.004), Bacteroidetes and lactobacilli; however, less diversity was observed for Bifidobacter (1.7< H′<3.08, P<0.05) and Clostridium coccoides (0.9< H′<2.98, P = 0.007). In this study, no significant difference was found in total bacterial quantity (P>0.05). GC/MS-based multivariate analysis delineated the faecal metabolites of IBS from nIBS samples. Elevated levels of amino acids (alanine and pyroglutamic acid) and phenolic compounds (hydroxyphenyl acetate and hydroxyphenyl propionate) were found in IBS. These results were highly correlated with the abundance of lactobacilli and Clostridium, which indicates an altered metabolism rate associated with these gut micro-organisms. A higher diversity of Bacteroidetes and Lactobacillus groups in IBS faecal samples also correlated with the respective total quantity. In addition, these changes altered protein and carbohydrate energy metabolism in the gut.

Metabolomics analysis reveals the compositional differences of shade grown tea (Camellia sinensis L.).

The different cultivation methods affect tea quality by altering the basic metabolite profiles. In this study, the metabolome changes were investigated in green tea and shade cultured green tea (tencha) by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) coupled with a multivariate data set. The principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA) of green tea clearly showed higher levels of galloylquinic acid, epigallocatechin, epicatechin, succinic acid, and fructose, together with lower levels of gallocatechin, strictinin, apigenin glucosyl arabinoside, quercetin p-coumaroylglucosyl-rhamnosylgalactoside, kaempferol p-coumaroylglucosylrhamnosylgalactoside, malic acid, and pyroglutamic acid than tencha. The effects of some seasonal variations were also observed in the primary metabolite concentrations such as amino acids and organic acids. In addition, green tea showed stronger antioxidant activity than tencha in both April and July. The antioxidant activity of green tea samples were significantly correlated with their total phenol and total flavonoid contents. This present study delineates the possibility to get high umami and less astringent green teas in shade culture. It highlights the metabolomic approaches to find out the effect of cultivation methods on chemical composition in plants and the relationship with antioxidant activity.

Correlation between Antioxidative Activities and Metabolite Changes during Cheonggukjang Fermentation

Liquid chromatography mass spectrometry and multivariate analysis were employed to investigate the correlation between fermentation time-dependent metabolite changes in cheonggukjang, a traditional fermented soybean product, and changes in its antioxidant activity over 72 h. The metabolite patterns were clearly distinguished not by strains but by fermentation time, into patterns I (0–12 h), II (12–24 h), and III (24–72 h), which appeared as distinct clusters on principal component analysis. The compounds that significantly contributed to patterns I, II, and III were soyasaponins, isoflavonoid derivatives, and isoflavonoid aglycons respectively. Partial least square analysis for metabolite to antioxidant effects showed correlations between the ferric reducing/antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay during 24–36 h, and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) test and total phenol content (TPC) during 36–72 h. Compared with the strong negative correlations of glucosylated-isoflavonoids with DPPH, ABTS and TPC during fermentation, the isoflavonoid aglycon displayed strong positive correlations with these compounds during fermentation.

GC-MS based metabolite profiling of rice Koji fermentation by various fungi.

In this study, Aspergillus kawachii, Aspergillus oryzae, and Rhizopus sp., were utilized for rice Koji fermentation, and the metabolites were analyzed in a time-dependent manner by gas chromatography-mass spectrometry. On Principal Component Analysis, the metabolite patterns were clearly distinguished based on the fungi species. This approach revealed that the quantities of glucose, galactose, and glycerol gradually increased as a function of fermentation time in all trials rice Koji fermentation. The time-dependent changes of these metabolites showed significant increases in glucose in the A. oryzae-treated rice, and in glycerol and galactose in the A. kawachii-treated rice. In addition, glycolysis-related enzyme activities were correlated with the changes in these metabolites. The results indicate that time-dependent metabolite production has the potential to be a valuable tool in selecting inoculant fungi and the optimal fermentation time for rice koji.

Effect of fermented soybean product (Cheonggukjang) intake on metabolic parameters in mice fed a high-fat diet.

As a nontargeted metabolomics approach, we investigated changes in the plasma metabolite levels in a mouse model of obesity induced by a high-fat diet and fermented soybean product diet. We analyzed the plasma samples by using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). In the present study, the animals were divided into four groups according to the diet type; normal fat diet control group (ND), high-fat diet control group (HD), high-fat diet plus 30% cooked soybean power (HD + S), and high-fat diet plus 30% 72-h fermented Cheonggukjang powder (HD + CGJ). To examine the changes in plasma metabolite levels because of high-fat diet feeding, total cholesterol and triglyceride levels were measured. Total cholesterol and triglyceride levels were lower in the HD + S and HD + CGJ groups than in the ND group. According to partial least-squares discriminant analysis (PLS-DA), major metabolites contributing to the discrimination between each group were assigned as lipid metabolites in plasma, e.g., lyso-phosphatidylcholines and phosphatidylcholines. Therefore, diets containing soy-based food products, which are rich sources of isoflavonoids, might be helpful for controlling the lipid metabolism under high-fat diet conditions.

Influence of iron regulation on the metabolome of Cryptococcus neoformans.

Iron is an essential nutrient for virtually all organisms and acts as a cofactor for many key enzymes of major metabolic pathways. Furthermore, iron plays a critical role in pathogen-host interactions. In this study, we analyzed metabolomic changes associated with iron availability and the iron regulatory protein Cir1 in a human fungal pathogen Cryptococcus neoformans. Our metabolite analysis revealed that Cir1 influences the glycolytic pathway, ergosterol biosynthesis and inositol metabolism, which require numerous iron-dependent enzymes and play important roles in pathogenesis and antifungal sensitivity of the fungus. Moreover, we demonstrated that increased cellular iron content and altered gene expression in the cir1 mutant contributed to metabolite changes. Our study provides a new insight into iron regulation and the role of Cir1 in metabolome of C. neoformans.

Identification of a new phomoxanthone antibiotic from Phomopsis longicolla and its antimicrobial correlation with other metabolites during fermentation

Identification of a new phomoxanthone antibiotic from Phomopsis longicolla and its antimicrobial correlation with other metabolites during fermentation

A Correlation between Antioxidant Activity and Metabolite Release during the Blanching of Chrysanthemum coronarium L.

Liquid chromatography tandem mass spectrometry (LCMS/MS)-based metabolite profiling was applied to elucidate the correlation between metabolite release and antioxidant activity during water blanching of Chrysanthemum coronarium L. (CC). Some major metabolites showing differences between fresh CC and blanched CC (BCC) were selected by principal component analysis (PCA) and partial least-square discriminate analysis (PLS-DA) loading plots, and were identified as dicaffeoylquinic acid (DCQA), succinoyl-DCQA, and acetylmycosinol. By PLS regression analysis of the correlation between antioxidant components and effects, candidate antioxidative metabolites were predicted due to strong positive correlations with DCQA and succinoyl-DCQA, and by a relatively weak positive correlation with acetylmycosinol.

Metabolomics-Based Optimal Koji Fermentation for Tyrosinase Inhibition Supplemented with Astragalus Radix

The present study was focused on improving the quality of rice koji by fermentation with a selected Aspergillus oryzae strain and a plant Astragalus radix. A. oryzae KCCM 60345 was used as main inoculant and the Astragalus radix was added as supplement in rice koji preparation. LC-MS based metabolite analysis and tyrosinase inhibitory activities were studied for different time periods. A. oryzae KCCM 60345 fermented rice koji supplemented with Astragalus showed higher tyrosinase inhibition activity at 4 d of fermentation and metabolite analysis with PCA and PLS-DA indicated differences in kojic acid, calycosin-7-O-β-D-glucoside, ononin, calycosin, and formononetin as compared with other forms of rice koji fermentation. By correlation analysis between metabolites and tyrosinase inhibitory activity, calycosin and kojic acid were identified as major tyrosinase inhibitors. Based on these results, we concluded that A. oryzae KCCM 60345 supplemented with Astragalus radix is useful for whitening effects, and we identified optimal conditions for rice koji preparation.

MS Based Metabolomic Application for Fermentation Analysis

The metabolomics is the studies on metabolites, and by-products of the chemical reactions that continuously go on in every biological system. The combined mass spectrometry approaches used in this study may be useful in understanding the overall fermentation metabolism in the various microbes.