• Korean Journal of Weed Science
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• v.17 no.4
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• pp.421-430
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• 1997

This experiment was conducted to detect the presence of allelopathic substances in the leaves of Ginkgo biloba L. Water extracts from G. biloba leaves which collected at different season markedly inhibited the germination and growth of O. sativa, E. crus-galli, D. sanguinalis, and L. sativa, indicating the presence of biological substances. Linolenic and palmitic acid were the major fatty acids of G. biloba leaves. The biochemical substances such as salicylic arid, p-coumaric acid, catechol, hydroquinone, orchinol, ferulic acid, phloroglucinol, and umbelliferone etc., belonging to the phenolic, compounds were, detected in a large amount, which may be responsible for exhibition inhibitory effects. The common phenolic compounds were detected in the early-harvested and late-harvested G. biloba leaves were salicylic and p-coumaric acid. All these compounds were related to the allelopathic activities in G. biloba leaves.

• Journal of Dairy Science and Biotechnology
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• v.28 no.2
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• pp.19-24
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• 2010

Milk components and their derivatives are a rich source of bioactive substances and play a central role in the development of functional foods. Many scientific evidences have shown that milk proteins have a biological health-promoting functionality. However, in recent times, dairy calcium and growth factors derived from milk have been misunderstood to cause diseases such as osteoporosis or cancer. This review focuses on the importance of milk-derived growth factors and some minor active components and briefly considers the emerging trends of personalized nutrition in future dairy research and development.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.115-124
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• 1984

Chlorsulfuron (chemical name : 2-Chloro-N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-aminocarbonyl-benzenesulfonamide) is a herbicidally active ingredient which shows effect against susceptible weeds already at such low rates like 5-20g active ingredient per hectare. In the here reported trials metabolism in several sensitive cultivated plants and weeds have been analysed using ^{14}C-labelled active ingredient. The uptake of chlorsulfuron by leaves or the root system is good in all plants species, and translocation takes place either symplasmatically or apoplasmatically. Metabolism takes place in all investigated plant species by development of hydrophile suhstances in roots and shoots. Decomposition of chlorsulfuron in roots and shoots of tolerant species (Triticum aestivum and Hordeum vulgare) to polare substances takes place quantitatively faster and quicker than in susceptible species (Beta vulgaris and Matricaria chamomilla).

• The Korean Journal of Physiology
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• v.2 no.1
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• pp.59-71
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• 1968

The uptake of phenolsulfonphthalein (PSP) and of paraaminohippuric acid (PAH) by cortical slices of the rabbit kidney was investigated while varying the composition of medium. The overall uptake of these substances displayed typical active transport characteristics and was significantly enhanced in presence of acetate. When the phosphate buffer was used the optimal pH was 7.4 for both substances. However, when the tris-buffer was used the optimal pH was 7.4 for PSP and 8.3 for PAH. Removal of $Na^+$ from the medium resulted in a significant reduction in the uptake. Similar results, though lesser in magnitude, were obtained when either $K^+\;or\;Ca^{++}$ was removed from the medium. However, there was no additive effect when $K^+\;and/or\;Ca^{++}$ were additionally removed from the $Na^+-free$ medium. The presence of ${NH_4}^+$ greatly reduced while $Li^+\;and\;Mg^{++}$ moderately reduced the uptake of both substances. However, choline had no effect. In substrate-leached slices, acetate greatly enhance the uptake of organic acids; but this action was not demonstrable in absence of $Na^+,\;K^+\;or\;Ca^{++}$.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.637-645
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• 1994

The effect of various drugs on the stability of the liposomal membrane of phosphatidylcholine and cholesterol was studied, employing the fluorescence self-quenching method. Calcein was entrapped into the phospholipid small unilamellar vesicles and the leakage of the fluorescence probe was monitored on adding the drug to the system. The results of the experiments showed that phenothiazine derivatives, some potent local anesthetics and surface active agents were very effective in inducing the leakage of calcein from the liposome. The leakage-inducing activity of these drug substances has been ascribed to their surface activity and the perturbation of the liposomal membrane by these substances. On the other hand drug substance with low surface activity or without amphiphilic moieties did not show any effect or only small effect on the leakage of calcein from the liposomes. The effect of lipid concentration on the stability of the liposomes was also investigated to show that the higher concentrations of lipid more drug was required to induce the leakage. The effect of surface charges of vesicles was also studied, and the results showed that the charge on the liposomes enhanced the stability of the liposomes against the leakage-inducing activity of these drug substances.

• Journal of Microbiology
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• v.34 no.3
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• pp.284-288
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• 1996

Among the bacteria isolated from compost piles of cattle excretion in a pasture located at the suburbs of Chunchon city, Pseudomonas aeruginosa KMCS-1 was selected for the test of antifungal substances produced. Six fractions were separated by silica gel column chromatography, and then the antifungal activity of each fraction was assayed against Escherichia coli, Bacillus subtilis, Candida albicans, Rhizopus sp., Aspergillus nidulans, Coprinus cinereus, and Pyricularia oryzae by paper disc method. Two fractions showed significant suppressive activities against A. nidulans, C. cinereus, and P. oryzae however, their mycelial growth was not affected by neither of these fractions. Inhibitory activities of these fractions to sporulation was assayed at the concentration of 50. 25, 12. 5, and 6.25 $\mu$g/ml and the average inhibition rates against sporulation of A. nidulans, C. cinereus, and P. oryzae were 94.0, 98.3, and 77.9%, respectively. Further purification and analysis of active substances are now being conducted.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.62-62
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• 2019

Natural substances have various physiological activities. Substances isolated from natural substances are known to be safer and more potent than pharmaceuticals. Potatoes not only act as energy sources but also contain active ingredients such as vitamins and minerals. In particular, the potato contains a large amount of polar compounds, including the saponin in the polar compounds, and the physiological activity of the saponins, such as immunity enhancement, antioxidant and anti-inflammatory is known. In this study, the antioxidative activity of polar compounds from five potatoes was examined by chemical base anti-oxidation assay and cell based anti-oxidation assay. In the chemical base anti-oxidation assay, DPPH experiment showed activity in the order of Hongyoung, Haryung, Seohong, Sumi, and Jayoung. In the LPA experiment, IC50 was lower in the order of Jayoung, Seohong, Sumi, Hongyoung, and Haryung. In the cell based anti-oxidation assay, the smallest amount of ROS was generated when the compound was derived from Haryung and hongyoung, and strong SOD activity was observed in Sumi and Jayoung. The results of this study reveal the antioxidative effect of polar compounds extracted from various kind of potatoes, which will enable the acquisition of new bioactive candidates and the establishment of new profit generation models for farmers.

• Applied Biological Chemistry
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• v.36 no.2
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• pp.99-104
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• 1993

In order to explore the brassinosteroid-active component in Cassia tora, methanol extract of immature seeds was purified by sequences of solvent fractionation, silica gel adsorption chromatography, Sephadex LH-20 chromatography, charcoal adsorption chromatography and Bondesil chromatography. The activity of brassinosteroid was monitored by the rice inclination test and its presence could be confirmed in each purification step. The purified active components were separated by silica gel adsorption chromatography. Brassinosteroid substances in separated active fractions were identified as teasterone, castasterone, brassinolide by TLC and HPLC. Our work is probably the first report of endogenous brassinosteroid in Cassia tora. The content of brassinosteroid in Cassia tora as converted into brassinolide was $3.5{\sim}5.5\;ng/g$ fresh weight. The order of brassinosteroid contents was toward to be teasterone, castasterone, brassinolide.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.13-13
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• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.

• Mycobiology
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• v.47 no.3
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• pp.329-334
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• 2019

Streptomyces blastmyceticus strain 12-6 was isolated from a forest soil sample of Cheonan area on the basis of strong antifungal activities against plant pathogenic fungi. Butanol extracts of the cultural filtrates were active against C. acutatum, C. coccodes, C. gloeosporioides, F. oxysporum, and T. roseum. Active fractions were prepared by thin layer chromatography using silica gel plate; 12-6-2 ($R_f$ 0.36), 12-6-3 ($R_f$ 0.44). Scanning electron microscopy showed that the active fractions caused a change in surface texture of fungal spores from smooth surface to wrinkled surface. The lethal effect on the spores of the active fractions varied from 56% to 100%. It was shown that the spores of C. acutatum were more sensitive to the antifungal fractions than the spores of F. oxysporum. Fluorescence staining using TOTO-1 indicated that the antifungal fractions could make the spores more sensitive to the fluorescence dye. Thus, it was suggested that antifungal agents prepared in this study exhibited the antifungal activity by damaging the plasma membrane of both fungal spores and hyphae. Identification of antifungal agents in the active fraction using GC-MS analysis revealed the presence of cyclo-(Leu-Pro) and 9-octadecenamide as major components that have already been known as antifungal substances.