• Bulletin of the Korean Chemical Society
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• v.24 no.10
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• pp.1478-1484
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• 2003

CRAMP was identified from a cDNA clone derived from a mouse femoral marrow cells as a member of cathelicidin-derived antimicrobial peptide. Tertiary structure of CRAMP in TFE/$H_2O$ (1 : 1, v/v) solution has been determined by NMR spectroscopy previously and consists of two amphipathic $\alpha-helices$ from Leu4 to Lys10 and from Gly16 to Leu33. These two helices are connected by a flexible region from Gly11 to Gly16. Analysis of series of fragments composed of various portion of CRAMP revealed that an 18-residue fragment with the sequence from Gly16 to Leu33 (CRAMP-18) was found to retain antibacterial activity without cytotoxicity. The effects of two Phe residues at positions 14 and 15 of CRAMP-18 on structure, antibacterial activity, and interaction with lipid membranes were investigated by $Phe^{14,15}$ ${\rightarrow}$ Ala substitution (CRAMP-18-A) in the present study. Substitution of Phe with Ala in CRAMP-18 caused a significant reduction on antibacterial and membrane-disrupting activities. Tertiary structures of CRAMP-18 in 50% TFE/$H_2O$ (1 : 1, v : v) solution shows amphipathic ${\alpha}$-helix, from $Glu^2{\;}to{\;}Leu^{18}$, while CRAMP-18-A has relatively short amphipathic ${\alpha}$-helix from $Leu^4{\;}to{\;}Ala^{15}$. These results suggest that the hydrophobic property of $Phe^{14}{\;}and{\;}Phe^15$ in CRAMP-18 is essential for its antibacterial activity, ${\alpha}$-helical structure, and interactions with phospholipid membranes.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.560-566
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• 2001

This study was conducted to investigate the effects of solvent extracts from medicinal plants on the fermentation of kimchi. Five microorganisms related to kimchi fermentation were selected and the antimicrobial activities of solvent fractions from medicinal plants were investigated. The chloroform fraction from the methanol extract of dandelion (Taraxacum platycarpum D.) exhibited inhibitory activity against five strains such as Lactobacilli plantarum, Lactobacilli brevis, Leuconostoc mesenteroides, Enterococcus faecalis and Saccharomyces cerevisiae. The chloroform fraction from the methanol extract of Dandelion inhibited the growth of E. faecalis and Leu. mesenteroides at the concentration of 80 mg/mL. Scanning electron micrographs of Leu. mesenteroides and E. faecalis treated with chloroform fraction 80 mg/mL exhibited morphological changes, including irregularly contracted cell surface.

• Food Engineering Progress
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• v.21 no.4
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• pp.383-390
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• 2017

Glucansucrase is an enzyme classified as a glycoside hydrolase (GH) 70 family, which catalyzes the synthesis of glucooligosaccharides with a low molecular weight using sucrose as a donor of D-glucopyranose and maltose as a carbohydrate acceptor. In this study, glucansucrase-producing lactic acid bacteria strain was isolated from the fermented foods collected in traditional markets, and the optimum conditions for the oligosaccharide production were investigated. The strain CCK940 isolated from Chinese cabbage kimchi was selected as an oligosaccharide-producing strain due to its high glucansucrase activity, with 918.2 mU/mL, and identified as Leuconostoc lactis. The optimum conditions for the production of oligosaccharides using Leu. lactis CCK940 were to adjust the initial pH to 6.0, add 5% (w/v) sucrose and 10% (w/v) maltose as a donor and acceptor molecules, respectively, and feed 5% (w/v) sucrose at 4 and 8 h of cultivation. When Leu. lactis CCK940 was cultured for 12 h at optimum conditions, at least four oligosaccharides with a polymerization degree of 2-4 were produced.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.85-98
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• 1995

Six malformin B's produced by Aspergillus niger van Tiegh. were separated by HPLC. Their structures determined by the methods of amino acid analyses, mass spectrometry, and two-dimensional NMR were revealed as cyclic pentapeptides structurally related to malformin $A_1$. Both the NMR and MS/MS data suggest that the respective structures of separated malformin B's were as follows; cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-allo-Ile for $B_{1a}$, cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-Leu for $B_{1b}$, cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Leu for $B_2$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Leu for $B_3$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Ile for $B_4$, and cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Ile for $B_5$. Among the malformin B's, the structure of $B_{1b}$ was the same as that of malformin $A_3$ or C. All the malformin B's showed physiological activities in the two assay systems using corn(Zea mays L.) roots and mung bean(Phaseolus aureus Roxb.) hypercotyl segments. The malformin B's with molecular weight 529 were more effective for inducing corn root curvature than those with molecular weight 515. The difference in molecular weight of malformin B's, i.e., the retention time on HPLC, results in the polarity change of the whole malformin molecule which affects the revealation of the malformin activities. In addition, the disulfide form of the malformin B's gives the rigidity of the molecule, whereas the combination of the fourth and the fifth amino acid residues provides the optimal three-dimensional configuration to the malformin receptor of plants. Presumably, these two factors are appeared to be essential for the greatest physiological activity of malformin B's. malformin $B_{1a}$ caused the corn root curvature by 90% at a concentration of $0.25{\mu}M$. However, such differential activities with molecular weight of 529 or 515 of malformin B's were not found in the mung bean hypercotyl segment test. Maximum stimulation of mung bean hypercotyl growth was observed at $0.1{\mu}M$ concentration of malformin B's. The growth of the segments treated with $B_5$ was 154% greater than that of the control.

• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.91-94
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• 1993

A 3-isopropylmalate dehydrogenase (3-IPMD) gene was cloned from Kluyveromyces fragilis. pJK104 could complement Escherichia coli leuB and Saccharomyces cerevisiae leu2 auxotrophs. The coding region was subcloned and the nucleotide sequence was determined. A 1.8 Kb EcoRI/SphI fragment of pJK104 subcloned in pUC18 could still complement the leuB mutation. An open reading frame of 1164 bp that corresponds to a polypeptide of 387 amino acids was found in the cloned fragment. The homology between the 3-isopropylmalate dehydrogenase of S. cerevisiae and that of K. fragilis was 68.13％ in nucleotides.

• Food Science of Animal Resources
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• v.36 no.4
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• pp.452-457
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• 2016

Lactoferrin is a glycoprotein with various biological effects, with antibacterial activity being one of the first effects reported. This glycoprotein suppresses bacterial growth through bacteriostatic or bactericidal action. It also stimulates the growth of certain kinds of bacteria such as lactic acid bacteria and bifidobacteria. In this study, Asn-Leu-Asn-Arg was selected and chemically synthesized based on the partial sequences of bovine lactoferrin tryptic fragments. Synthetic Asn-Leu-Asn-Arg suppressed the growth of Pseudomonas fluorescens, P. syringae and Escherichia coli. P. fluorescens is a major psychrotrophic bacteria found in raw and pasteurized milk, which decreases milk quality. P. syringae is a harmful infectious bacterium that damages plants. However, synthetic Asn-Leu-Asn-Arg did not inhibit the growth of Lactobacillus acidophilus. It is expected that this synthetic peptide would be the first peptide sequence from the bovine lactoferrin C-lobe that shows antibacterial activity.

• Mass Spectrometry Letters
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• v.10 no.4
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• pp.117-122
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• 2019

This study demonstrated the sensitivity of electron capture dissociation mass spectrometry (ECD-MS) to probe subtle conformational changes in gaseous melittin ions induced by the substitution of an amino acid. ECD-MS was performed for triply and quadruply-protonated melittin and its variants obtained by a single amino acid substitution, namely, D-Pro14, Pro14Ala, and Leu13Ala. Although native triply-protonted melittin showed only a few peptide backbone cleavage products, the D-Pro14 and Pro14Ala variants exhibited extensive backbone fragments, suggesting the occurrence of a significant structural or conformational change induced by a single amino acid substitution at Pro14. On the contrary, the substitution at Leu13, namely Leu13Ala (+3), did not cause significant changes in the ECD backbone fragmentation pattern. Thus, the sensitivity of ECD-MS is demonstrated to be good enough to probe the aforementioned conformational change in melittin.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1480-1483
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• 2009

The KNR wayside and onboard subsystem has completed commissioning tests applicable to the Pilot Line section by BOMBARDIER. Andreas Hardt/Assessor and Rod Muttram/VP, Quality & safety approved the Automatic Train Protection(ATP) System. However additional evidences are necessary to come to a Specific Application, which is mandatory to approve the Generic Applications included for commercial running on the overall main line railway with ATP. According to Factory Acceptance Test plan, CBC, CBF, LEU(Line Electronic Unit) made by domestic factory is tested by official recognition test Standards-Setting Agency. It is important to verify quality which form checklist during Factory Acceptance Test. In this paper, review the process, test item, norm and checklist for the CBC, CBF, LEU.

• Journal of Ginseng Research
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• v.21 no.1
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• pp.35-38
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• 1997

We investigated the effects of ginseng protopanaxadiol (PD) and protopanaxatriol (PT) saponins on the spontaneous contractility of intestine. Treatment with PD saponins showed a slight inhibition of spontaneous contraction of rabbit jejunum. In contrast, PT saponins showed much larger inhibition with dose-dependent manner in a range of 25~250 $\mu\textrm{g}$/ml. The inhibitory effect by PT saponins was not desensitized with continuous presence of PT saponins for several minutes. In addition, leu-enkephalin (1 PM) also inhibited the spontaneous contraction of rabbit jejunum but the in- hibition by leu-enkephalin was desensitized rapidly. The presence of PT saponins prevented the desenstization induced by leu-enkephalin. In conclusion, we found that PT saponins exert inhibition of spontaneous contractility of rabbit jejunum and the pattern of inhibition is different from that of opioid.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.50-56
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• 1997

The mode of action of mastoparan B, an antimicrobial cationic tetradecapeptide amide isolated from the hornet Vespa basalis, toward phospholipid bilayers was studied with synthetic mastoparan B and its analogs with individual Ala instead of hydrophobic amino acids (1-Ile, 3-Leu, 6-Leu, 7-Val, 9-Trp, 13-Val, 14-Leu) in mastoparan B. Mastoparan B and its analogs were synthesized by the solid-phase method. Circular dichroism spectra showed that mastoparan B and its analogs adopted an unordered structure in buffer solution. In the presence of neutral and acidic liposomes, most of the peptides took an α-helical structure. The calcein leakage experiment indicated that mastoparan B interacted strongly with neutral and acidic lipid bilayers than its analogs. Mastoparan B also showed a more or less highly antimicrobial activity and hemolytic activity for human erythrocytes than its analogs. These results indicate that the hydrophobic face in the amphipathic α-helix of mastoparan B critically affect biological activity and helical contents.