• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1527-1535
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• 2018

Bacterial strain BAS23 was isolated from rice field soil and identified as Bacillus amyloliquefaciens. Based on dual culture method results, the bacterium BAS23 exhibited potent in vitro inhibitory activity on mycelial growth against a broad range of dirty panicle fungal pathogens of rice (Curvularia lunata, Fusarium semitectum and Helminthosporium oryzae). Cell-free culture of BAS23 displayed a significant effect on germ tube elongation and mycelial growth. The highest dry weight reduction (%) values of C. lunata, H. oryzae and F. semitectum were 92.7%, 75.7%, and 68.9%, respectively. Analysis of electrospray ionization-mass spectrometry (ESI-MS) and $^1H$ nuclear magnetic resonance (NMR) spectroscopy revealed that the lipopeptides were iturin A with a C14 side chain (C14 iturinic acid), and a C15 side chain (C15 iturinic acid), which were produced by BAS23 when it was cultured in nutrient broth (NB) for 72 h at $30^{\circ}C$. BAS23, the efficient antagonistic bacterium, also possessed in vitro multiple traits for plant growth promotion and improved rice seedling growth. The results indicated that BAS23 represents a useful option either for biocontrol or as a plant growth-promoting agent.

• KSBB Journal
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• v.31 no.4
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• pp.263-269
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• 2016

For decades, the microorganisms in arctic soils have been newly discovered according to the climate change and global warming. In this study, the chemical structure of a lipid A molecule from Pseudomonas sp. strain PAMC 28615 which was newly discovered from arctic soils was characterized by mass spectrometric approaches such as matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and MALDI multi-stage tandem mass spectrometry (MS). First, lipopolysaccharide (LPS) from Pseudomonas sp. strain PAMC 28615 was extracted and subsequently hydrolyzed to obtain the lipid A. The parent ion peak at m/z 1632 was determined by MALDI-TOF MS, which also can validate our lipid A purification method. For detailed structural determination, we performed the multiple-stage tandem mass analysis ($MS^4$) of the parent ion, and subsequently the abundant fragment ions in each MS stage are tested. The fragment ions in each MS stage were produced from the loss of phosphate groups and fatty acyl groups, which could be used to confirm the composition or the position of the lipid A components. Consequently, the mass spectrometry-based lipid A profiling method could provide the detail chemical structure of lipid A from the Pseudomonas sp. strain PAMC 28615 as an arctic bacterium from the frozen arctic soil.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.676-680
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• 2003

Dissolution of magnetite powders by 0.05 M citric acid was investigated at $50^{\circ}C$. All the tests were performed in the pH range between 2.0 to 5.0, which was adjusted using nitric acid or sodium hydroxide. Concentration of each of the dissociated chemical species of citric acid under various solution pHs was calculated using the ionization constants. Variation of zeta potential of magnetite with pH changes was also investigated. The dissolution reaction was explained by comparing the concentration of the dissociated chemical species of citric acid with the zeta potential. Longer than 3 h of induction time was required to dissolve the magnetite. The dissolution behaviour of magnetite was well described by the equation. The physical meaning of each parameter was explained successfully from the model equation.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.166-176
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• 2022

Banana peels are also widely used as bio-adsorbent in the removal of chemicals contaminants and heavy metals from water and soil. GC-MS plays an essential role in the phytochemical analysis and chemo taxonomic studies of medicinal plants containing biologically active components. Intrinsically, with the use of the flame ionization detector and the electron capture detector which have very high sensitivities, Gas chromatography can quantitatively determine materials present at very low concentrations and most important application is in pollution studies. In the present study banana peels were used as bio-adsorbent to remediate the heavy metal contaminated water taken from three different stations located around the industrial belts of Ranipet, Tamilnadu, India. The AAS analysis of the samples shows a decrement of chromium concentration of 98.93%, 96.16% and 96.5% in Station 1, 2 and 3 respectively which proves the efficiency of the powdered peels of Musa paradisiaca. The GC-MS analysis of the control and treated peels of Musa paradisiaca reveals the presence of phytochemicals like Acetic Acid, 1-Methylethyl Ester, DL-Glyceraldehyde Dimer, N-Hexadecanoic Acid, 3-Decyn-2-Ol, 26-Hydroxy, Cholesterol, Ergost-25-Ene-3,5,6,12-Tetrol, (3.Beta.,5.Alpha.,6.Beta.,12.Beta.)-, 1-Methylene-2b-Hydroxymethyl-3, and 3-Dimethyl-4b-(3-Methylbut-2-Enyl)-Cyclohexane in the control banana peels. The banana peels which were used for the treatment reveals the changes and alteration of the phytochemicals. It is concluded that the alteration in phytochemicals of the experimental banana peels were due to adsorption of chromium heavy metal from the sample.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4636-4643
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• 2022

A time-of-flight and energy (TOF-E) detection system for the measurement of ²³⁶U accelerator mass spectrometry (AMS) has been developed to improve the ²³⁶U/²³⁸U sensitivity at Micro Analysis Laboratory, Tandem accelerator (MALT), The University of Tokyo. With observing TOF distribution of ²³⁵U, ²³⁶U and ²³⁸U, this TOF-E detection system has clearly separated ²³⁶U from the interference of ²³⁵U and ²³⁸U when measuring three kinds of uranium standards. In addition, we have developed a novel method combining kernel-based density estimation method and multi-Gaussian fitting method to estimate the ²³⁶U/²³⁸U sensitivity of the TOF-E detection system. Using this new estimation method, 3.4 × 10^-12 of ²³⁶U/²³⁸U sensitivity and 1.9 ns of time resolution are obtained. ²³⁶U/²³⁸U sensitivity of TOF-E detection system has improved two orders of magnitude better than that of previous gas ionization chamber. Moreover, unknown species other than uranium isotopes were also observed in the measurement of a surface soil sample, which has demonstrated that TOF-E detection system has a higher sensitivity in particle identification. With its high sensibility in mass determination, this TOF-E detection system could also be used in other heavy isotope AMS.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.753-759
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• 2023

The genus Paenibacillus contains a variety of biologically active compounds that have potential applications in a range of fields, including medicine, agriculture, and livestock, playing an important role in the health and economy of society. Our study focused on the bacterium SS4^T (KCTC 43402^T = GDMCC 1.3498^T), which was characterized using a polyphasic taxonomic approach. This strain was analyzed using antiSMASH, BAGEL4, and PRISM to predict the secondary metabolites. Lassopeptide clusters were found using all three analysis methods, with the possibility of secretion. Additionally, PRISM found three biosynthetic gene clusters (BGC) and predicted the structure of the product. Genome analysis indicated that glucoamylase is present in SS4^T. 16S rRNA sequence analysis showed that strain SS4^T most closely resembled Paenibacillus marchantiophytorum DSM 29850^T (98.22%), Paenibacillus nebraskensis JJ-59^T (98.19%), and Paenibacillus aceris KCTC 13870^T (98.08%). Analysis of the 16S rRNA gene sequences and Type Strain Genome Server (TYGS) analysis revealed that SS4^T belongs to the genus Paenibacillus based on the results of the phylogenetic analysis. As a result of the matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS) results, SS4^T was determined to belong to the genus Paenibacillus. Comparing P. marchantiophytorum DSM 29850^T with average nucleotide identity (ANI 78.97%) and digital DNA-DNA hybridization (dDDH 23%) revealed values that were all less than the threshold for bacterial species differentiation. The results of this study suggest that strain SS4^T can be classified as a Paenibacillus andongensis species and is a novel member of the genus Paenibacillus.