• The Plant Pathology Journal
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• v.38 no.2
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• pp.115-130
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• 2022

Though information exists regarding the pathogenesis of the shot-hole disease (SH) in flowering cherry (FC), there has been a lack of research focusing on SH management. Therefore, here, we investigated the inhibitory activities of antagonistic bacteria against SH pathogens both in vitro and in vivo as well as their biochemical characteristics and bioactive compounds. Two biosurfactant-producing bacterial antagonists, identified as Bacillus velezensis strains JCK-1618 and JCK-1696, exhibited the best effects against the growth of both bacterial and fungal SH pathogens in vitro through their cell-free culture filtrates (CFCFs). These two strains also strongly inhibited the growth of the pathogens via the action of their antimicrobial diffusible compounds and antimicrobial volatile organic compounds (VOCs). Crude enzymes, solvent extracts, and biosurfactants of the two strains exhibited antimicrobial activities. Liquid chromatography/electrospray ionization time-of-flight mass spectrometric analysis of the partially purified active fractions revealed that the two antagonists produced three cyclic lipopeptides, including iturin A, fengycin A, and surfactin, and a polyketide, oxydifficidin. In a detached leaf assay, pre-treatment and co-treatment of FC leaves with the CFCFs led to a large reduction in the severity of the leaf spots caused by Epicoccum tobaicum and Bukholderia contaminans, respectively. In addition, the two antagonists produced indole-3-acetic acid, siderophore, and a series of hydrolytic enzymes, along with the formation of a substantial biofilm. To our knowledge, this is the first report of the antimicrobial activities of the diffusible compounds and VOCs of B. velezensis against the SH pathogens and their efficiency in the biocontrol of SH.

• Korean Journal of Environmental Agriculture
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• v.41 no.1
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• pp.50-54
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• 2022

BACKGROUND: Phyllospadix japonica Makino is a perennial plant belonging to the family Zosteraceae. This species is native to the eastern coast of the Korean Peninsula, and it is found attached to rocks on the seashore. As with all seagrass species, P. japonica is also known to play a major role in protecting the marine environment, and studies on its physiological activities suggestive of its antioxidant, antibacterial and anti-inflammatory potentials have been reported. In this study, purification and structural analysis were performed to identify the polyphenol substances derived from P. japonica. METHODS AND RESULTS: An polyphenol substance MP-1 was purified from the 70% aqueous methanol extract of P. japonica using Diaion® HP-20 column chromatography, ODS column chromatography, and medium-pressure liquid chromatography (MPLC). The purified MP-1 was identified as rosmarinic acid having a molecular weight of 360 and a molecular formula of C18H16O8 through electrospray ionization (ESI)-mass and nuclear magnetic resonance (NMR) spectroscopic analysis. CONCLUSION(S): This study highlights the processes used for the identification of the polyphenol substance derived from P. japonica. Rosmarinic acid, the polyphenol derived from P. japonica identified by this study, is a kind of bioactive substance mainly present in plants. These findings provide an important starting point and are valuable for future studies on bioactive substances in seagrass.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.797-805
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• 2023

Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 - 3), designated as vernogratiosides A-C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with α-glucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.

• Animal Bioscience
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• v.36 no.9
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• pp.1367-1375
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• 2023

Objective: Pigment production and distribution are controlled through multiple proteins, resulting in different coat color phenotypes of sheep. Methods: The expression distribution of vimentin (VIM) and transthyretin (TTR) in white and black sheep skins was detected by liquid chromatography-electrospray ionization tandem MS (LC-ESI-MS/MS), gene ontology (GO) statistics, immunohistochemistry, Western blot, and quantitative real time polymerase chain reaction (qRT-PCR) to evaluate their role in the coat color formation of sheep. Results: LC-ESI-MS/MS results showed VIM and TTR proteins in white and black skin tissues of sheep. Meanwhile, GO functional annotation analysis suggested that VIM and TTR proteins were mainly concentrated in cellular components and biological process, respectively. Further research confirmed that VIM and TTR proteins were expressed at significantly higher levels in black sheep skins than in white sheep skins by Western blot, respectively. Immunohistochemistry notably detected VIM and TTR in hair follicle, dermal papilla, and outer root sheath of white and black sheep skins. qRT-PCR results also revealed that the expression of VIM and TTR mRNAs was higher in black sheep skins than in white sheep skins. Conclusion: The expression of VIM and TTR were higher in black sheep skins than in white sheep skins and the transcription and translation were unanimous in this study. VIM and TTR proteins were expressed in hair follicles of white and black sheep skins. These results suggested that VIM and TTR were involved in the coat color formation of sheep.

• Analytical Science and Technology
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• v.22 no.4
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• pp.319-325
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• 2009

An effective and specific procedure for confirmation of neomycin, aminoglycoside antibiotic in honey was developed and validated. Honey was adjusted to pH 2 with 0.1M HCl and applied to weak cation-exchange SPE cartridge. Neomycin was eluted with basified methanol. Following separation by ion-pairing liquid chromatography, neomycin was analysed with positive electrospray ionization and MRM mode. Quantification was linear over the range of $5.0{\sim}250.0{\mu}g/kg$ ($r^2$ >0.9951). The precision (R.S.D.) and accuracy (as a bias) of quality control samples in honey ranged 11.5~18.7% and 10.9~20.9%, respectively. Established method can be applied to analysis of neomycin in honey.

• Analytical Science and Technology
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• v.20 no.2
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• pp.115-123
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• 2007

The heterocyclic amines (HAs) are a family of mutagenic/carcinogenic chemicals formed from the cooking of muscle meats such as beef, meat, fowl, and fish. A major draw back in the analysis of HAs from foods is their very low level of concentration (ng/g) and a number of matrix interferences in samples. Solid-phase extraction (SPE) is one of the procedures widely used for the extraction and purification of HAs in food samples. In this study, several SPE procedures of HAs determination were performed. Recoveries of the HAs were obtained from comparing a matrix such as a standard methanolic solution and pre-cooked meat extracts. Recovery values were ranging between 25.3 and 93.0 % at a concentration of 25.0 ng/g. HAs were determined with high sensitivity by micro-HPLC (${\mu}$-HPLC) analysis with electrospray ionization mass spectrometry (ESI-MS). Another developed method, which is freezing filtration method, shows better extraction recoveries and good precisions. The established method will be applicable to monitoring of heterocyclic amines from the cooked meat.

• Korean Journal of Food Science and Technology
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• v.41 no.3
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• pp.326-333
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• 2009

Heterocyclic aromatic amines (HCAs) are mutagenic and carcinogenic substances that are formed during the heating of protein-rich foods. HCAs are generally found at low amounts in a complex matrix, which requires sophisticated analysis. In this study, HCAs were extracted from lyophilized fish and shellfish samples using solid-phase extraction (SPE) and determined by liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI-MS). The HCA recoveries in the fish and shellfish ranged from 15.7 to 74.7% with standard deviations from 0.2 to 7.63%. And HCA concentrations ranged from 0.8 to 1,117.7 $ng/g^{-1}$ in cooked food samples. 1-methyl-9H-pyrido[3,4-b]indole (Harman), 9H-pyrido[3,4-b]indole (Norharman), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were the most abundant HCAs formed in the muscle of fried mackerel, at levels of 1,117.7, 926.6, and 133.7 ng/g, respectively. 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-aminodipiryrido[1,2-a:3,2-d]imidazole(Glu-P-2), 2-amino-9H-pyrido[2,3-b]indole(A${\alpha}$C), 2-amino-3methyl-9H-pyrido [1,2-a:3,2-d]imidazole(MeA${\alpha}$C), 2-amino-3,4,7,8-tetramethylimidazo[4,5-f]quinoxaline (TriMeIQx), 2-amino-3,7,8-trimethylimidazo [4,5-f]quinoxaline(7,8-DiMeIQx), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) were only detected by small quantities ranged from 1.5 to 98.6 ng/g. Overall, this study provides useful information on HCA levels in fish and shellfish products consumed in Korea.

• Journal of Life Science
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• v.22 no.11
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• pp.1456-1462
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• 2012

Sorafenib is a multikinase inhibitor and an oral anticancer drug approved for the treatment of patients with advanced renal cell carcinoma and those with unresectable hepatocellular carcinoma. The purpose of this study was to develop an efficient method of the determination of sorafenib in human plasma using tandem mass spectrometry coupled with liquid chromatography (LC/MS/MS) and validate the method by the guidelines of the Korean Food and Drug Administration (KFDA). Plasma samples ($100{\mu}l$) were added with chlorantraniliprole as an internal standard and then mixed with the 0.1% formic acid-containing extraction solution composed of isopropyl alcohol and ethyl acetate (1:4, v/v). After centrifugation, the supernatant was concentrated at $45^{\circ}C$ under negative pressure and centrifugal force. The residue was reconstituted with a mobile phase and injected into the HPLC instrument using a reverse phase Waters XTerra$^{TM}$ C18 column (particle size $3.5{\mu}m$). Liquid chromatography was carried out within the run time of 5 min using a mobile phase composed of buffer (0.1% formic acid and 10 mM ammonium formate), methanol, and acetonitrile (1:6:3, v/v/v). The analytes were monitored by tandem mass spectrometry in the multiple reaction monitoring method programmed to detect sorafenib at 'm/z 465.2 ${\rightarrow}$ 252.5' and chlorantraniliprole at 'm/z 484.4 ${\rightarrow}$ 286.2' with positive electrospray ionization mode ($ES^+$). The result showed the proper linearity ($r^2$ > 0.99) over the range of 2,000-5,000 ng/ml with good accuracy (90.7-103.9%) and precision (less than 10%). The newly developed method using LC/MS/MS was validated by the guideline of KFDA and identified as more sensitive compared to the previous methods.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.475-482
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• 2008

Methanol extracts of peanut (Arachis hypogaea L.) pods were chromatographed, which yielded 3 phytochemicals 1-3 including 5,7-dihydroxychromone (1), eriodictyol (2), and 3',4',5,7-tetrahydroxyflavone (3). To confirm the presence of isolated phytochemicals, the pods extracts were performed by high performance liquid chromatography coupled with a photodiode array detector (HPLC-PDA) and a mass spectrometric detector (MSD) with electrospray ionization (ESI). Optimum extraction conditions for phytochemical contents using peanut germplasm were obtained by employing 90% MeOH for 12 hr at room temperature and phytochemicals 1-3 showed significant differences with concentrations of $407.56{\pm}23.35$, $52.92{\pm}5.11$, and $2,024.34{\pm}134.18\;{\mu}g/g$, respectively. Under this optimal conditions, the contents of phytochemicals 1-3 in peanut pods of 3 Korea cultivars including 'Jakwang', 'Daekwang', and 'Palkwang' exhibited phytochemical 3 was the highest range of $1,338.01-5,162.93\;{\mu}g/g$, followed by phytochemical 1 ($590.13-1,382.10\;{\mu}g/g$), and phytochemical 2 ($25.12-186.85\;{\mu}g/g$), respectively. Moreover, 'Jakwang' exhibited the highest contents of phytochemical (1: $1,362.10{\pm}52.49$, 2: $186.85{\pm}17.69$, and 3: $5,162.93{\pm}148.64\;{\mu}g/g$, respectively), whereas the lowest contents was found in the 'Daekwang' (1: $590.13{\pm}22.23$, 2: $25.12{\pm}2.45$, and 3: $1,338.01{\pm}62.17\;{\mu}g/g$, respectively). These results suggest that the methanol extracts of peanut pods may possess health related benefits to humans owing to various known biological activities of phytochemicals 1-3.

• Journal of Pharmaceutical Investigation
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• v.38 no.4
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• pp.261-267
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• 2008

The aim of the present study was to evaluate the bioequivalence of two gabapentin preparations. We used Neurontin tablet 800 mg (Pfizer Korea Inc.) as a reference drug for bioequivalence of Gabalep tablet 800 mg (Chong Kun Dang Pharmaceutical Co., Korea), and performed this whole study according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty five healthy male volunteers were administered with each drug in a randomized $2{\times}2$ cross-over study with one week washout interval. After drug administration, blood was taken at predetermined time intervals ($0{\sim}24$ hours) and the concentrations of gabapentin in serum were determined using an high performance liquid chromatography-tandem mass spectrometer (LC-MS/MS) employing electrospray ionization technique and operating in multiple reaction mornitoring (MRM). The analytical method was validated in specificity, accuracy, precision and linearity. The phar-macokinetic parameters such as AUCt and Cmax were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed AUCt and Cmax. $Mean{\pm}SD$. of AUCt and Cmax value for reference drug and test drug were $29.94{\pm}9.23\;({\mu}g/mL{\cdot}hr)$ and $3.12{\pm}1.11\;({\mu}g/mL{\cdot}hr)$, and $31.48{\pm}9.77\;({\mu}g/mL{\cdot}hr)$ and $3.15{\pm}1.03\;({\mu}g/mL)$, respectively. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log(0.8) to log(1.25) for AUCt and Cmax, respectively. These results indicate that Gabalep tablet 800 mg is bioequivalent to Neurontin tablet 800 mg.