• CELLMED
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• v.4 no.1
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• pp.5.1-5.8
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• 2014

Healthcare-associated infection represents a frequent cause of mortality that increases hospital costs. Due to increasing microbial resistance to antibiotics, it is necessary to search for alternative therapies. Consequently, novel alternatives for the control of resistant microorganisms have been studied. Among them, plant antimicrobial protein presents enormous potential, with flowers being a new source of antimicrobial molecules. In this work, the antimicrobial activity of protein-rich fractions from flower tissues from 18 different species was evaluated against several human pathogenic bacteria. The results showed that protein-rich fractions of 12 species were able to control bacterial development. Due its broad inhibition spectrum and high antibacterial activity, the protein-rich fraction of Hibiscus rosa-sinensis was subjected to DEAE-Sepharose chromatography, yielding a retained fraction and a non-retained fraction. The retained fraction inhibits 29.5% of Klebsiella pneumoniae growth, and the non-retained fraction showed 31.5% of growth inhibition against the same bacteria. The protein profile of the chromatography fractions was analyzed by using SDS-PAGE, revealing the presence of two major protein bands in the retained fraction, of 20 and 15 kDa. The results indicate that medicinal plants have the biotechnological potential to increase knowledge about antimicrobial protein structure and action mechanisms, assisting in the rational design of antimicrobial compounds for the development of new antibiotic drugs.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.212-217
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• 2002

We purified polyphenols from persimmon leaf and tested their biological activity. The 60% acetone extract was lyophilized and applied to test enzyme inhibition of glucosyltransferase and tyrosinase. GTase was 82.4% inhibited at $1.8{\times}10^{-1}$ mg/ml and tyrosinase 21.7% inhibited at 0.8 mg/ml. The acetone extract was fractionated into F-1, 2, 3, 4, 5 by Sephadex Q-50 gel filtration and the fraction-1 and 2 showed higher enzyme inhibition activity than the other fractions. To the Proteinase K treatment and autoclaving of the two fractions had no effect on the enzyme activity, but these results suggested that active fraction was not protein but phenol ring completed compounds. By Sephadex LH-20, MCI-gel and Bondapak $C_{18}$ column chromatographies, compouds 1, 2, 3 and 4 from F-1 fraction, compounds 5 and 6 from F-2 fraction and compounds 7 , 8 from F-3 fraction were purified and re-crystallized. The purified compounds was assumed to be condensed tannins of frame flavan-3-ol frame on the basis of color reagent reaction and to be a mixture of monomer, dimer and trimer according to TLC analysis.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.594-600
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• 2018

Shiga toxin-producing Escherichia coli (STEC) is an important pathogenic bacterium. To control STEC, the characteristics of the ECP33 and NOECP91 coliphages, which belong to the Myoviridae family, were analyzed. The host inhibition range for a total of 44 STEC strains was 45.5% for ECP33 and 65.9% for NOECP91. ECP33 and NOECP91 were relatively stable at $65^{\circ}C$, 50 ppm of sodium hyperchlorite, and a pH value of 4-10. However, the two phages were susceptible to a temperature of $70^{\circ}C$. NOECP91 was killed within 1 h after exposure to 30% ethanol, but ECP33 showed high tolerance even after exposure to 70% ethanol for 1 h. Interestingly, the inhibition of STEC growth according to the multiplicity of infection of 0.1 was confirmed until no growth was observed after 10 hours of culture with the phages. Therefore, the ECP33 and NOECP91 phages may be applied as a biological control agent for Shiga toxin-producing E. coli.

• Journal of Life Science
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• v.26 no.11
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• pp.1245-1252
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• 2016

As a research of inflammation inhibitory activity using natural resource, the inflammation inhibitory activity by purified active compound from Rhododendron mucronulatum flower was experimented. Rhododendron mucronulatum flower components were purified and separated with Sephadex LH-20 and MCI gel CHP-20 column chromatography, Purified compound was confirmed as myricetin by $^1H-NMR$, $^{13}C-NMR$ and Fast atom bombardment (FAB)-Mass spectrum to have inhibition activity on inflammatory factors secreted by Raw 264.7 cells in response to lipopolysaccharide stimulation. Myricetin inhibited nitric oxide (NO) expression in a concentration dependent manner, approximately 40% inhibition was observed at a concentration of $50{\mu}M$. The inhibition effect of myricetin on inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expression was 20% and 80%, respectively, at a concentration of $25{\mu}M$. Myricetin also inhibited expression of the inflammatory cytokines, tumor necrosis factor $(TNF)-{\alpha}$, interleukin $(IL)-1{\beta}$, IL-6 and prostaglandin $E_2(PGE_2)$ in a concentration dependent manner; a concentration of $50{\mu}M$, 70%, 80%, 80% and 95% inhibition was observed, respectively. Therefore myricetin isolated from Rhododendron mucronulatum flowers is expected to have an anti-inflammatory effect in Raw 264.7 cell induced by lipopolysaccharides. The results can be expected myricetin from Rhododendron mucronulatum flower to use as functional resource for anti-inflammatory activity.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.54-62
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• 1995

Acetolactate synthase activity inhibition and herbicidal activities were investigated with 2 sulfonylureas [chlorsulfuron{2-chloro-N-{{(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino} carboxyl} benzenesulfonamide}, metsulfuron-methyl{methyl-2{{{{(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino}carbonyl}amino}sulfonyl}benzoic acid}, and 2 imidazoli-nones [imazethapyr{2-{4,5-dihydro-4-methyl-4-(1-methyl)-5-oxo-1H-imidazol-2-yl}-5-ethyl-3-pyridinecarboxylicacid}, imazaquin{2-{4,5-dihydro-4-methyl-4-(1-methyl)-5-oxo-1H-imidazol-2-yl}-3-quinoline carboxylic acid} herbicides. A broad weeding spectrum was observed with the treated herbicides at low application rates. Both corn(Zea mays L.) and sorghum(Sorghum bicolor Moench) were very sensitive to the two herbicide groups. Although legumes, such as soybean(Glycine max Merr.), clover(Trifolium repense L.), and indian jointvetch(Aeschnomene indica L.) were sensitive to the sulfonylureas, they were tolerant to the imidazolinones. On the contrary, wheat(Triticum aestivum L.) and barley(Hoderum sativum Jess.) showed the reverse responses of the legumes to the two herbicide groups. Quackgrass(Agropyron repens(L.) P. Beauv.). however, was commonly tolerant to the two herbicide groups. Degrees of crop injury and acetolactate synthase inhibition also varied with the crops examined. The 50% inhibition concentrations of sulfonylureas on acetolactate synthase in vitro activity($IC_{50}$) from corn, wheat, and soybean did not relate to the greenhouse herbicidal activities ($GI_{50}$). With chlorsulfuron, for example, wheat had more than 100 times higher $GI_{50}$ than corn and soybean, but the $IC_{50}$ was 4 to 10 times lower. Similar observation was made with metsulfuron-methyl. However, closer relationships between $IC_{50}$ and $GI_{50}$ were found with the imidazolinones. When imazethapyr was applied, the order of $GI_{50}$ values against com, wheat, and soybean was the same as that of $IC_{50}$.

• The Plant Pathology Journal
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• v.34 no.1
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• pp.44-58
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• 2018

Pseudomonas chlororaphis 30-84 is a biological control agent selected for its ability to suppress diseases caused by fungal pathogens. P. chlororaphis 30-84 produces three phenazines: phenazine-1-carboxylic acid (PCA), 2-hydroxy-phenazine-1-carboxylic acid (2OHPCA) and a small amount of 2-hydroxy-phenazine (2OHPHZ), and these are required for fungal pathogen inhibition and wheat rhizosphere competence. The two, 2-hydroxy derivatives are produced from PCA via the activity of a phenazine-modifying enzyme encoded by phzO. In addition to the seven biosynthetic genes responsible for the production of PCA, many other Pseudomonas strains possess one or more modifying genes, which encode enzymes that act independently or together to convert PCA into other phenazine derivatives. In order to understand the fitness effects of producing different phenazines, we constructed isogenic derivatives of P. chlororaphis 30-84 that differed only in the type of phenazines produced. Altering the type of phenazines produced by P. chlororaphis 30-84 enhanced the spectrum of fungal pathogens inhibited and altered the degree of take-all disease suppression. These strains also differed in their ability to promote extracellular DNA release, which may contribute to the observed differences in the amount of biofilm produced. All derivatives were equally important for survival over repeated plant/harvest cycles, indicating that the type of phenazines produced is less important for persistence in the wheat rhizosphere than whether or not cells produce phenazines. These findings provide a better understanding of the effects of different phenazines on functions important for biological control activity with implications for applications that rely on introduced or native phenazine producing populations.

• Mycobiology
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• v.46 no.2
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• pp.129-137
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• 2018

Black rot disease in orchids is caused by the water mold Phytophthora palmivora. To gain better biocontrol performance, several factors affecting growth and antifungal substance production by Pseudomonas aeruginosa RS1 were verified. These factors include type and pH of media, temperature, and time for antifungal production. The results showed that the best conditions for P. aeruginosa RS1 to produce the active compounds was cultivating the bacteria in Luria-Bertani medium at pH 7.0 for 21 h at $37^{\circ}C$. The culture filtrate was subjected to stepwise ammonium sulfate precipitation. The precipitated proteins from the 40% to 80% fraction showed antifungal activity and were further purified by column chromatography. The eluted proteins from fractions 9-10 and 33-34 had the highest antifungal activity at about 75% and 82% inhibition, respectively. SDS-PAGE revealed that the 9-10 fraction contained mixed proteins with molecular weights of 54 kDa, 32 kDa, and 20 kDa, while the 33-34 fraction contained mixed proteins with molecular weights of 40 kDa, 32 kDa, and 29 kDa. Each band of the proteins was analyzed by LC/MS to identify the protein. The result from Spectrum Modeler indicated that these proteins were closed similarly to three groups of the following proteins; catalase, chitin binding protein, and protease. Morphological study under scanning electron microscopy demonstrated that the partially purified proteins from P. aeruginosa RS1 caused abnormal growth and hypha elongation in P. palmivora. The bacteria and/or these proteins may be useful for controlling black rot disease caused by P. palmivora in orchid orchards.

• Journal of Life Science
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• v.14 no.3
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• pp.467-471
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• 2004

Bacillus sp. SD-10 was investigated to develope biological pesticides for control of mushroom diseases. Bacillus sp. SD-10 showed high antifungal activity when cultured at 35∼4$0^{\circ}C$ for 30∼4$0^{\circ}C$. The culture filtrate of the bacterium inhibited the growth of mycelium of T. virens which is a kind of mushroom pathogene. On the test of inhibition of spore germination of T. virens, more than 5% of the culture filtrate in the media inhibited completely the germination of the spores. An antimicrobial substance, UPX-1 was purified from the culture filtrate of the Bacillus. From the $^1H$-NMR and $^{13}C$-NMR spectrum analysis, the substance was indentifed as disaccharide composed to six carbon sugars. UPX-1 has not only strong antifungal activity against T. virens but also antibacterial activity against Pseudomonas tolaassi.

• BMB Reports
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• v.29 no.3
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• pp.230-235
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• 1996

The interaction of ${\alpha}-ketoglutarate$ dehydrogenase complex (${\alpha}-KGDC$) with a hydrophobic fluorescent probe [1,1'-bi(4-aniline)naphthalene-5,5'-disulfonic acid] (bis-ANS) was studied. The punfied ${\alpha}-KGDC$ was potently inhibited by bis-ANS with an apparent half maximal inhibitory concentration ($IC_{50}$) of 9.8 ${\mu}m$ at pH 8.0. The catalytic activities of both the E1o and E2o subunits were predominantly inhibited while that of the E3 component was hardly affected. The binding of bis-ANS to the enzyme caused a marked enhancement and blue shift from 523 nm to 482 nm in the fluorescence emission spectrum. The dissociation constant ($K_d$) and the number of binding sites (n) were calculated to be 0.87 mM and 158, respectively. Allosteric regulators such as purine nucleotides and divalent cations further increased the fluorescence intensity of the $bis-ANS-{\alpha}-KGDC$ binary complex. These data suggest that the binding of these allosteric regulators to ${\alpha}-KGDC$ may cause the conformational changes in the enzyme and that bis-ANS could be used as a valuable probe to study the interaction of the multi-enzyme complex and its allosteric regulators.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.301-310
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• 1994

This experiment was conducted to test the fungicidal activity of extracts from 50 medicinal plants to powdery mildew (Sphaerotheca fulinginea) and identify the bioactive substances. Among the medicinal plants tested, the water extract of Rheum undulatum was the most effective in spore germination inhibition, which inhibited by 100% at 200-fold dilution. Also, 50-fold dilution of water extract, 100-fold dilution of alcohol extract, 500-fold dilution of crude extract from Rheum undulatum and even 1000-fold dilution of reference chemical inhibited powdery mildew of cucumber more than 60%. 500-fold dilution of crude extract inhibited powdery mildew of cucumber 100% by twice spray treatment. There was phytotoxcity at the 100-fold dilution, but was not recognized this injury at the 500-fold dilution of crude extract. From our research to identify bioactive substance using HPLC, GLC and Mass spectrum analysis, it indicated that Rheum undulatum extract contained tentatively 1,8-dihydroxy-3-methyl-9,10-anthracenedione and 1,8-dihydroxy-3-methoxy-6-methyl-9,10-anthracenedione.