A5018157268- Microbial Natural Products and Biosynthesis
- Metabolomics and Mass Spectrometry Studies
- Synthetic Organic Chemistry Methods
- Molecular spectroscopy and chirality
- Chemical Synthesis and Analysis
- Advanced NMR Techniques and Applications
- Carbohydrate Chemistry and Synthesis
- Radical Photochemical Reactions
- Antibiotic Resistance in Bacteria
- Chemical synthesis and alkaloids
- Plant-Microbe Interactions and Immunity
- Cancer therapeutics and mechanisms
- Bioactive Compounds and Antitumor Agents
- Diet and metabolism studies
- Food composition and properties
- Algal biology and biofuel production
- Marine Sponges and Natural Products
- Plant Disease Resistance and Genetics
- Cancer, Hypoxia, and Metabolism
- Advanced Synthetic Organic Chemistry
- Genetics, Aging, and Longevity in Model Organisms
- Vibrio bacteria research studies
- Photochromic and Fluorescence Chemistry
- Infectious Diseases and Mycology
- Synthesis of Organic Compounds
Korea Institute of Science and Technology
2011-2024
Seoul National University
1998-2020
Zhejiang Wanli University
2013
Kyung Hee University East-West Neo Medical Center
2008
The effects of growth rate and nutrient feed on the production actinorhodin (Act) undecylprodigiosin (Red) were determined in Streptomyces coelicolor A3(2) a congenic relA null-mutant known to be deficient ppGpp synthesis antibiotic under conditions nitrogen limitation. In relA+ strain, Act was inversely related specific continuous cultures limited by glucose, ammonium, or phosphate, while Red biosynthesis optimal at 0.05 h-1 regardless Production mutant lower than that parental particularly...
Salinazinones A (1) and B (2), two unprecedented pyrrolidinyl-oxazinones, were isolated from the culture broth of Streptomyces sp. KMF-004 a solar saltern at Aphae Island, Korea. The structures these salinazinones, which are unusual consist 2-methylpropenyl-1,3-oxazin-6-one bearing 1-oxopyrrolidinyl substituents, assigned by spectral chemical analyses using Mosher's method, circular dichroism (CD), calculated ECD. first examples natural alkaloid class composed an oxazinone–pyrrolidone conjugate.
Isotopomer analysis using either 13C NMR or LC/GC–MS has been an invaluable tool for studying metabolic activities in a variety of systems. Traditional challenges are, however, that 13C-detected is insensitive despite its high resolution, and MS-based techniques cannot easily differentiate positional isotopomers. In addition, current limitations detecting metabolites living cells. Here, we describe non-uniform sampling-based 2D heteronuclear single quantum coherence (NUS HSQC) approach to...
Gut microbiota are major contributors to host metabolism and considered as potential targets of novel therapeutics. Microalgae have a strong for use prebiotics because they rich source proteins, fatty acids, fiber, minerals nutritional supplementation in humans. Nevertheless, there has been insufficient research into the effect microalgae on gut microbiota. To investigate effects three edible (Chlorella vulgaris, Chlorella protothecoides, Schizochytrium sp.) microbiota, simulated digestion...
This study is focused on the involvement of unusual nucleotide (p)ppGpp during morphological and physiological differentiation Streptomyces clavuligerus. In particular, functional structural elements two genes encoding proteins RelA Rsh were identified. The relA gene encodes an 843 aa protein (RelA), while rsh a 738 (Rsh). disrupted by insertion hygromycin resistance apramycin gene, respectively. synthesis ppGpp in gene-disrupted mutant was completely eliminated under conditions starvation...
AMP-activated protein kinase (AMPK in human and AAK C. elegans) is a master regulator of metabolism. It has many isotypes, but its isotype-dependent functions are largely unknown. By developing real-time in-organism NMR metabolomics for elegans, we were able to study different roles the isotypic catalytic subunits AAK/AMPK, AAK-1, AAK-2 live worms at whole organism level. The aak-1 knockout animals exhibited enhanced glucose production under starvation, strikingly opposite aak-2 animals....
Photodynamic therapy is a noninvasive treatment in which specific photosensitizers and light are used to produce high amounts of reactive oxygen species (ROS), can be employed for targeted tissue destruction cancer or antimicrobial therapy. However, it remains unknown whether lower ROS produced by mild photodynamic increase lifespan stress resistance at the organism level. Here, we introduce novel (PDTr) that uses 20 μM hypericin, photosensitizer originates from Hypericum perforatum, orange...
Abstract Phenylpropanoids are naturally occurring secondary metabolites that exhibit various biological activities such as ultra-violet (UV) light protection and reactive-oxygen species (ROS) scavenging. In this study, we utilized a light-emitting diode (LED) based in-situ UV irradiation nuclear magnetic resonance (NMR) technique to monitor the photoisomerization reactions of these phenylpropanoids under in real-time. Through approach, measured photochemical reaction rates photostationary...
A new lucentamycin analogue, E (5), was isolated from the culture broth of marine-derived actinomycete Nocardiopsis lucentensis, strain CNR-712. The absolute stereostructure 5 assigned by comprehensive analyses NMR data and application advanced Marfey's method. planar structure analogous to lucentamycins A–D, whereas olefin geometry 3-methyl-4-ethylideneproline moiety found be E, opposite that previously reported. Consequently, a reinvestigation geometries residues A–D showed substituted...
Complex nuclear magnetic resonance (NMR) signals of organic compounds containing multiple analogous substructures or mixtures pose a significant challenge to structural identification, thus resulting in frequent misassignment structures. The GEMSTONE method, single-scan technique that selectively excites specific proton signal among the crowded NMR signals, was recently proposed as solution. However, its extension polarization transfer method for heteronuclear spin systems unsuccessful....
We found that an extract of Lycoris chejuensis and its three isolated active components, narciclasine, 7-deoxynarciclasine, 7-deoxy-trans-dihydronarciclasine, each significantly reduced the formation amyloid-β peptides in HeLa cells transfected with amyloid precursor protein carrying Swedish mutation up to 45 ± 3.6%. The down-regulated protein, especially mature form by 88%, ability secretases generate toxic amyloid-β. Double-transgenic mice treated for 4 months also showed levels plaques...
Two new pyrrolosesquiterpenes, glaciapyrroles D (1) and E (2) were discovered along with the previously reported glaciapyrrole A (3) from Streptomyces sp. GGS53 strain isolated deep-sea sediment. This study elucidated planar structures of 1 2 using nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV), infrared (IR) spectroscopic data. The absolute configurations determined by Mosher’s method, circular dichroism spectroscopy, X-ray crystallography. Under 366 nm UV...
Our approach provides high-resolution and distortion-free NMR for metabolic tracer analysis. It confirmed the conventional mechanism of dichloroacetate suggested a new one involving an enhanced contribution PPP to cytosolic serine synthesis.
The diagnostic ability of the restriction fragment length dimorphism–polymerase chain reaction (RFLD–PCR) method was evaluated. Seven primer pairs, newly designed from 44 β-lactamase genes encoding extended-spectrum β-lactamases not related to TEM- and SHV-types, were used differentiate OXA-2, FOX-3, CMY-3, IMP-1, IMI-1 β-lactamases. RFLD–PCR carried out successfully, these differentiated by sizes their PCR products difference in when each amplicon digested with a unique enzyme. This...
The oral consumption of capsicum has been reported to increase interleukin (IL)-2 and interferon (IFN)-γ production in Peyer's patches (PP); however, the active components responsible for these effects have not completely identified. beneficial biological green peppers cultivated under environmentally friendly farming conditions (ECP), without use chemical pesticides, rarely compared with those conventional (CCP). Oral administration ECP extract significantly induced IL-2 IFN-γ concanavalin...
of mRNA expression GS were detected in the tissues hemocytes and mantle.Up-regulation by challenge with bacteria Vibrio parahaemolyticus bacterial wall lipopolysaccharides showed that plays a role anti-bacterial immunity.We conclude pathogen infection significantly induces level Tg-GS, activation influences immune response T. granosa increasing glutamine concentration.
Glutamine plays key roles as a biosynthetic precursor or an energy source in cancers, and interest its metabolism is rapidly growing. However, the proper evaluation of glutamine hydrolysis, very first reaction entire glutaminolysis, has been difficult. Here, we report triple resonance NMR-based assay for specific detection glutaminase activity carrying out this using stable-isotope labeled glutamine. Compared to conventional methods involving coupled enzyme assays, proposed approach direct...
In NMR analysis of complex organic molecules, low natural abundance 13C and the resolution two-dimensional (2D) experiments are significant difficulties. Also challenging is a mixture spectrum without separation, which has been limited to simple molecules. Through nonuniform sampling using modified heteronuclear multiple bond correlation combined with indirect covariance, high-resolution 13C–13C was obtained 1H sensitivity. Built on thus-obtained connectivities, deconvolution spectra...
Fatty acid
Nonenzymatic reactions, though critical in natural product biosynthesis, are significantly challenging to control. Adding 3% NaI the culture medium of