• BMB Reports
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• v.53 no.7
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• pp.349-356
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• 2020

Mass spectrometry (MS) is an ideal tool for analyzing multiple types of (bio)molecular information simultaneously in complex biological systems. In addition, MS provides structural information on targets, and can easily discriminate between true analytes and background. Therefore, imaging mass spectrometry (IMS) enables not only visualization of tissues to give positional information on targets but also allows for molecular analysis of targets by affording the molecular weights. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS is particularly effective and is generally used for IMS. However, the requirement for an organic matrix raises several limitations that get in the way of accurate and reliable images and hampers imaging of small molecules such as drugs and their metabolites. To overcome these problems, various organic matrix-free LDI IMS systems have been developed, mostly utilizing nanostructured surfaces and inorganic nanoparticles as an alternative to the organic matrix. This minireview highlights and focuses on the progress in organic matrix-free LDI IMS and briefly discusses the use of other IMS techniques such as desorption electrospray ionization, laser ablation electrospray ionization, and secondary ion mass spectrometry.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.637-642
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• 2002

Thirty Holstein calves were used to determine effects of age, environment and sex on blood metabolite concentrations during 1 to 90 d of age. Calves were weaned at 75 d of age. Environmental effects are grouped by the difference in month at birth and site of feeding. Blood samples were obtained every 2 or 3 d. The mean metabolite concentration every 3 d was used for the statistical analysis. Dairy bodyweight gain was not affected by environmental group and sex effect. Concentrations of plasma glucose, nonesterified fatty acids (NEFA), triglyceride, total cholesterol and total ketone changed with growth. These developmental changes in metabolite levels would be caused by ruminal maturation with increment of grain intake. Levels of plasma urea nitrogen, glucose, NEFA, triglyceride and total cholesterol drastically changed during a few weeks after birth, indicating that the physiological state in calves greatly changed during that time. Effects of the environmental group and sex were significant in almost all metabolites. Temperature influenced plasma metabolite concentrations. The plasma metabolite concentrations were affected more intensely by heat stress in the infant period than in the neonatal period.

• Natural Product Sciences
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• v.21 no.4
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• pp.278-281
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• 2015

Chemical investigation on a colonial marine tunicate, Didemnum sp. led to the isolation of a series of indole alkaloids including a new (1) and two known metabolites (2-3). Based on the spectroscopic analysis including 1D and 2D NMR along with MS spectra, the structure of 1 (16-epi-18-acetyl herdmanine D) was elucidated as a new amino acid derivative. The absolute configuration of 1 was determined by comparison of specific rotation with the known compound. The structures of compounds 2 and 3 were also identified as bromoindole containing compounds N-(6-bromo-1H-indole-3-carbonyl)-L-arginine and (6-bromo-^1H-indol-3-yl) oxoacetamide, respectively, based on $^1H$ and $^{13}C$ NMR data, MS data and specific rotation value. Their pharmacological potentials as antibacterial agents and FXR antagonists were investigated, but no significant activity was found. However, the structural similarity of compound 1 to compound 4 suggested the anti-inflammatory potential of compound 1.

• The Plant Pathology Journal
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• v.29 no.2
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• pp.174-181
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• 2013

The plant growth-promoting rhizobacterium Ochrobactrum lupini KUDC1013 elicited induced systemic resistance (ISR) in tobacco against soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum. We investigated of its factors involved in ISR elicitation. To characterize the ISR determinants, KUDC1013 cell suspension, heat-treated cells, supernatant from a culture medium, crude bacterial lipopolysaccharide (LPS) and flagella were tested for their ISR activities. Both LPS and flagella from KUDC1013 were effective in ISR elicitation. Crude cell free supernatant elicited ISR and factors with the highest ISR activity were retained in the n-butanol fraction. Analysis of the ISR-active fraction revealed the metabolites, phenylacetic acid (PAA), 1-hexadecene and linoleic acid (LA), as elicitors of ISR. Treatment of tobacco with these compounds significantly decreased the soft rot disease symptoms. This is the first report on the ISR determinants by plant growth-promoting rhizobacteria (PGPR) KUDC1013 and identifying PAA, 1-hexadecene and LA as ISR-related compounds. This study shows that KUDC1013 has a great potential as biological control agent because of its multiple factors involved in induction of systemic resistance against phytopathogens.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.158-158
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• 1998

The non-mevalonate pathway is a newly discovered isoprenoid biosynthetic pathway in some bacteria, cyanobacteria, algae and plants. Because isoprenoid metabolites (ubiquinone, menaquinone, undecaprenol) are essential for bacterial growth, this pathway may represent a novel target for antibacterial agents. Antibiotics with a unique mechanism of action are needed to combat the risk of antibiotic resistance that is a current worldwide problem. In order to study this pathway as viable target, it was necessary to verify use of the pathway in our model system, the bacterium Bacillus subtilis. Incubation experiments with [6,6-$^2$H$_2$]-D-glucose and [l-$^2$H$_3$]-deoxy-D-xylulose were conducted to provide labeled menaquinone-7 (MK -7), the most abundant isoprenoid in B. subtilis. $^2$H-NMR analysis of the MK-7 revealed labeling patterns that strongly support utilization of the non-mevalonate pathway. Another approach to study the pathway is by structure activity relationships of proposed inhibitors of the pathway. Fosmidomycin is a phosphonic acid with antibacterial activity known to inhibit isoprenoid biosynthesis in susceptible bacteria and may act by inhibiting the non-mevalonate pathway. Fosmidomycin and an N-methyl analog were synthesized and tested for antibacterial activity. Fosmidomycin was active against Escherichia coli and B. subtilis, while N-formyl-N-methyl-3-amino-propylphosphonic acid was inactive.

• Biomolecules & Therapeutics
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• v.23 no.5
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• pp.414-420
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• 2015

Flavonoids, such as fisetin (3,7,3',4'-tetrahydroxyflavone), are plant secondary metabolites. It has been reported that fisetin is able to perform numerous pharmacological roles including anti-inflammatory, anti-microbial, and anti-cancer activities; however, the exact anti-inflammatory mechanism of fisetin is not understood. In this study, the pharmacological action modes of fisetin in lipopolysaccharide (LPS)-stimulated macrophage-like cells were elucidated by using immunoblotting analysis, kinase assays, and an overexpression strategy. Fisetin diminished the release of nitric oxide (NO) and reduced the mRNA levels of inducible NO synthase (iNOS), tumor necrosis factor (TNF)-${\alpha}$, and cyclooxygenase (COX)-2 in LPS-stimulated RAW264.7 cells without displaying cytotoxicity. This compound also blocked the nuclear translocation of p65/nuclear factor (NF)-${\kappa}B$. In agreement, the upstream phosphorylation events for NF-${\kappa}B$ activation, composed of Src, Syk, and I${\kappa}B{\alpha}$, were also reduced by fisetin. The phospho-Src level, triggered by overexpression of wild-type Src, was also inhibited by fisetin. Therefore, these results strongly suggest that fisetin can be considered a bioactive immunomodulatory compound with anti-inflammatory properties through suppression of Src and Syk activities.

• Korean Journal of Veterinary Service
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• v.38 no.4
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• pp.259-264
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• 2015

We investigated the residues of 6 cephalosporins (cefquinome, cephalexin, cephalonium, cefazolin, ceftiofur, cefuroxime) using LC-MS/MS in raw meat in Seoul. This method involves extraction of the residue from the meat by distilled water and methanol followed by a manual of residue analysis published by the National Institute of Food and Drug Safety Evaluation. The recoveries ranged between 74.71~90.01% in beef, 73.37~101.40% in pork and 70.87~95.53% in chicken, respectively. The limits of detection were 0.0004~0.0563 mg/kg, and the limits of quantification were 0.001~0.169 mg/kg respectively. Residues of cephalosporins which exceeded maximum residue limits (MRL) were not exceed in any of the 287 samples. However, it is necessary to develop multi-method, which includes the active metabolites of ceftiofur.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2345-2350
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• 2009

As part of an effort to discover bioactive natural products from marine sources, we investigated the bioactive secondary metabolites from two marine isolates of the fungi, Trichoderma viride and Rhizopus stolonifer. Three cyclopentenones, myrothenones A (1) and B (2) and trichodenone A (3), were isolated from T. viride and two cyclopentenones, 2-bromomyrothenone B (4) and botrytinone (5), were isolated from R. stolonifer. The molecular structures and absolute stereochemistries of the cyclopentenones were determined from chemical and physicochemical evidence, including quantum chemistry calculations, X-ray analysis, and the circular dichroism (CD) exciton chirality method. Myrothenone A (1) displays tyrosinase inhibitory activity, with an I$C_{50}$ value of 6.6 ${\mu}M$, and is therefore more active than the positive control, kojic acid.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.331-338
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• 2014

Myxococcus stipitatus KYC4013 extract exhibited the most potent antifungal activity among the extracts of 207 Myxococcus strains isolated in Korea. High-resolution LC-MS analysis revealed that M. stipitatus KYC4013 produces five antifungal substances and three other secondary metabolites that were predicted to be melithiazol and phenalamide derivatives, respectively. The putative melithiazol derivatives were best produced in CYS medium and the putative phenalamide derivatives were best produced in VY3 medium.

• Korean Journal of Plant Resources
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• v.33 no.6
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• pp.597-603
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• 2020

Red ginseng marc (RGM) has been used on primary industries using fertilizer or forage, and it mostly has been dumped. To improve utilization of RGM, the biological activities of RGM were examined. RGM was extracted and fractionated using various solvents and their biological activities were compared. The hexane fraction from the methanol extract of RGM (RGMMH) showed strong anti-cancer activity (58.56 ± 6.04% at 100 ㎍/mL) and anti-inflammatory effect (65.72 ± 1.33% at 100 ㎍/mL). But, oil extract of RGM extracted with hexane (RGMH) showed low activities (anti-cancer: 16.42 ± 3.33%, at 100 ㎍/mL, anti-inflammatory activity: 29.46 ± 2.10%, at 100 ㎍/mL). Their metabolites were analyzed using HPLC. Panaxydol known as anti-cancer compound of RGM was one of major compounds in RGMMH. Meanwhile, panaxydol was detected in trace amount in red ginseng marc oil (RGMH). In addition, RGMMH and RGMH showed big differences in HPLC profiling. This research suggests optimal extraction method of RGM oil.