• Food Science and Biotechnology
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• v.14 no.2
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• pp.196-199
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• 2005

Antimicrobial activity of persimmon leaf tea methanol extracts on Klebsiella pneumoniae and Staphylococcus aureus was examined through paper disk diffusion bioassay. K. pneumoniae and S. aureus showed 87.64 and 99.35% growth inhibitions by addition of steamed tea methanol extracts (10 mg/ml), respectively. The number of microorganisms in rice cakes was significantly reduced when leaf tea powder was added during production of rice cakes. Addition of 1% steamed leaf teas to rice cakes decreased the number of microorganisms by over 50%, and over 70% reduction was observed when final 2% (dried weight w/w) steamed leaf tea was added, whereas no significant effect was observed over 2%. These results indicate that different microorganisms were detected from persimmon leaf and rice cake, and persimmon leaf can inhibit normal microbial growth in rice cake.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.82-86
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• 1996

Three thousand microbial strains collected from different sources were screened for herbicidal activity. A strain of ME-9189 showed herbicidal activity against Digitaria sanguinalis and Portulaca oleracea was isolated from a mountainy soil. Based on taxonomic studies, the strain was identified as Streptomyces tubercidicus. The active compound of ME-9189 was purified from the culture broth by charcoal, silica gel, sephadex LH-20 column chromatography and crystalization, consecutively. The ME-9189 compound was identified as tubercidin by spectroscopic methods of UV, $^{1}H$ and $^{13}C$-NMR, and EIMS. In the bioassay, growth of radish shoot and root was inhibited by 50% with tubercidin treatment of 10 ppm, showing 2 times higher activity than that of herbicidin A and similar to that of toyocamycin.

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.53-58
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• 2008

The plant Quisqualis indica (Compositae) has ehnopharmcological reputation of being used as a healing agent in Bangladesh. In this study, preliminary screenings were conducted to look at the antimicrobial susceptibility and cytotoxicity of the plant extract. The extractives of the plant were subjected to screening for inhibition of microbial growth by the disc diffusion method. The zones of inhibition demonstrated by the n-hexane, carbon tetrachloride, chloroform and aqueous soluble partitionates of the methanolic extract ranged from 8 - 15 mm, 8 - 18 mm, 12 - 20 mm and 10 - 16 mm, respectively at a concentration of 400 ${\mu}g$/disc. All the extractives were also subjected to brine shrimp lethality bioassay for primary cytotoxicity evaluation. Here, the carbon tetrachloride soluble materials demonstrated the highest cytotoxicity with $LC_{50}$ of 0.826 ${\mu}g$/ml, while n-hexane, chloroform and aqueous soluble partitionates of the methanolic extract revealed the $LC_{50}$ of 1.254, 3.866 and 5.366 ${\mu}g$/ml, respectively. This is the first report of the antimicrobial activity and cytotoxicity Q. indica.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.3
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• pp.33-37
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• 2004

Objective: The aim of this work is to investigate the antibacterial activity of the Sohporaflavanone G isolated from Sophora flavescens (S. flavescens), as the development of microbial resistance to antibiotics make it essential to constantly look for new and active compounds effective against pathogenic bacteria. Method : Sophoraflavanone G was isolated from the dried roots of Sophora flavescens Aiton (Leguminosae) by bioassay?guided fractionation. We investigated the effect of sophoraflavanone G on oral bacterial at various concentrations after incubation of 24 h in strains in the dose?dependent manner. Results: The structure of active compound, Sophoraflavanone G having a lavandulyl group at C?8, was elucidated on the basis of spectral data especially 1H?NMR and I3C?NMR. The antimicrobial activity showed that Sophoraflavanone G exhibited antimicrobial activilies against all the bacteria tested (MICs, 0.39 - 6.25 ㎍／ml). Sophoraflavanone G showed the strong antimicrobial activity against all the facultative bacteria and microaerophilic bacteria (MICs, 0.78 - 1.56 ㎍／ml) and also Sophoraflavanone G showed the strong antimicrobial activity against obligate anaerobic bacteria (MICs, 0.39 - 6.25 ㎍／ml).

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.454-459
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• 2013

Beet armyworm, Spodoptera exigua is difficult to control using chemical insecticides because of the fast development of insecticide resistance. For eco-friendly beet armyworm managements, various control agents are required. Entomopathogenic fungus is one of the promise control agents as an alternative to chemical control agent. We isolated entomopathogenic fungi from soil samples of Yangpyeong, Gyeonggi-do by insect-bait method using Tenebio molitor and conducted bioassay to larva of beet armyworm. The result of bioassay, a selected strain FT83 showed 100% mortality against third instar larva of S. exigua. On the basis of morphological characteristics and analysis of 18srRNA sequence for ITS, the strain FT83 was identified as a Metarhizium anisopliae. The mortality of beet armyworm showed $81.6{\pm}9.3%$ at $1{\times}10^6$ conidia/ml, 100% at $1{\times}10^7$ conidia/ml and 100% at $1{\times}10^8$ conidia/ml respectively. Therefore, we recommend to proper control efficacy against S. exigua in which more than $1{\times}10^7$ conidia/ml suspension of M. anisopliae FT83.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.1
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• pp.54-60
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• 2005

A study was conducted with the objective of evaluating the nutritive value of some browse species from Kenya. The species evaluated included: Bauhinia alba, Bauhinia variegata, Bridelia micrantha, Calliandra calothyrsus, Carisa edulis, Cratylia argentea, Gliricidia sepium, Lantana camara, Maerua angolensis, Sesbania micrantha and S. sesban. The browses were evaluated by their chemical composition including phenolics, in vitro gas production and tannin activity (tannin bioassay). All the species had high crude protein content (149-268 g/kg DM) and low NDF content (239-549 g/kg DM). The feeds had varying contents of total extractable tannins (TET) ranging from low (3-22 mg/g DM), moderate (42-58 mg/g DM) and high (77-152 mg/g DM). Calliandra calothyrsus had the highest tannin content. Significant (p<0.05) variation in gas production was recorded among the species. Sesbania micrantha had the highest (p<0.05) potential gas production while Gliricidia sepium had the highest (p<0.05) rate of gas production. Use of polyethylene glycol (PEG 6000), to assess the adverse affect of tannins, indicated that tannins in browse species with high tannin content had inhibitory effects on rumen microbial fermentation as indicated by the gas production. Estimated organic matter digestibility and metabolizable energy also increased with PEG addition. The results of this study indicate that such Kenyan browse species have the potential to be used as feed supplements for ruminant animals.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.95.2-96
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• 2003

In order to develop a new microbial fungicide for the control of vegetable diseases using endophytic bacteria, a total of 260 bacterial strains were isolated from fresh tissues of 5 plant species. After they were cultured in broth media, their antifungal activities were screened by in vivo bioassays against Botrytis cinerea(tomato gray mold), Pythium ultimum(cucumber damping-off), Phytopkhora infestans(tomato late blight), Colletotrichum orbiculare(cucumber anthracnose), and Blumeria graminis f. sp. hordei(barley powdery mildew). As the results of screening, 38 bacterial strains showed potent antifungal activities against at least one of 5 plant pathogens. A bacterial strain EB072 displayed potent disease control activities against 3 plant diseases. Among the bacterial strains with a potent antifungal activity against cucunlber anthracnose, three bacterial strains, EB054, EB151 and EB215, also displayed a potent in vitro antifungal activity against C. acutatum, a fungal agent causing pepper anthracnose. A bacterial strain EB215 obtained from roots of cucumber was identified as Burkholderia cepacia based on its physiological and biochemical characteristics and 165 rRNA gene sequence. An antifungal substance was isolated from the liquid cultures of B. cepacia EB215 strain by ethyl acetate partitioning, repeated silica gel column chromatography, and invitro bioassay, Its structural determination is in progress by various instrumental analyses.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.685-691
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• 1998

Baculovirus Hyphantrin. cunea nuclear polyhedrosis virus (HcNPV) insecticide containing the insecticidal protein (ICP) gene from Bacillus thuringiensis subsp. kurstaki HD1 was constructed using a lacZ-HcNPV system. The ICP ($\delta$-endotoxin) gene was placed under the control of the polyhedrin gene promoter of the HcNPV. A polyhedrin-negative virus was derived and named ICP-HcNPV insecticide. Then, the insertion of the ICP gene in the ICP-HcNPV genome was confirmed by Southern hybridization analysis. Polyacrylamide gel electrophoresis (PAGE) analysis of the Spodoptera frugiperda cell extracts infected with the ICP-HcNPV showed that the ICP was expressed in the insect cells as 130 kDa at 5 days post-infection. The ICP produced in the cells was present in aggregates. When extracts from the cells infected with the ICP-HcNPV were fed to 20 Bombyx mori larvae, the following mortality rate was seen; 8 larvae at 1 h, 10 larvae at 3 h, and 20 larvae at 12 h. These data indicate that the B. thuringiensis ICP gene was expressed by the baculovirus insecticide in insect cells and there was a high insecticidal activity. The biological activities of the recombinant virus ICP-HcNPV were assessed in conventional bioassay tests by feeding virus particles and ICP to the insect larvae. The initial baculovirus insecticide ICP-HcNPV was developed in our laboratory and the significance of the genetically engineered virus insecticides is discussed.

• Ocean and Polar Research
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• v.29 no.4
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• pp.327-337
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• 2007

Plankton communities have close relationships with environmental changes in water columns. Thus, the use of plankton as a biological tool for assessing the marine ecosystem health may be effective. Major issue regarding coastal pollution has been usually recognized as phytoplankton blooms or red tides caused by the eutrophication, an increase in concentration of inorganic nutrients such as nitrogen and phosphorus. However, in order to understand the effects of the overall pollution on marine ecosystem, the organic pollutants as well as the inorganic nutrients should be also considered. For understanding the effects of the organic pollution, among the planktonic organisms, heterotrophic bacteria, heterotrophic flagellates and ciliates should be investigated. Generally, there are three approaches for assessing the marine ecosystem health using the plankton taxa or plankton communities. The first one is a community-based approach such as diversity index and chlorophyll a concentration which are common in analysis of the plankton communities. The second is an indiviual-based approach which is to monitor the pollution indicative species. This approach needs one's ability to identify the plankton to species level. The last approach is a bioassay of toxicity, which can be applied to the plankton. A pilot study in Masan Bay was conducted to assess the effects of the inorganic and organic pollution. In this article, a new approach using plankton communities was tentatively presented as a biological tool for assessing the ecosystem health of Masan Bay.

• Mycobiology
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• v.36 no.3
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• pp.173-177
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• 2008

The crude ethanol extracts (stem and fruits), their fractions and two triterpenes, $\beta$-Amyrin and 12-Oleanene 3$\beta$, 21$\beta$-diol, isolated as a mixture from the chloroform soluble fraction of an ethanolic extract of Duranta repens stem, were evaluated for antibacterial, antifungal activities by the disc diffusion method and cytotoxicity by brine shrimp lethality bioassay. The structures of the two compounds were confirmed by IR, $^1H$-NMR, $^{13}C$-NMR and LC-MS spectral data. The chloroform soluble fraction of stem and ethanol extract of fruits possess potent antishigellosis activity and also exhibited moderate activity against some pathogenic bacteria and fungi but the isolated compound 1 (mixture of $\beta$-Amyrin and 12-Oleanene 3$\beta$, 21$\beta$-diol) showed mild to moderate inhibitory activity to microbial growth. The minimum inhibitory concentrations (MICs) of the extracts (stem and fruits), their fractions and compound 1 were found to be in the range of 32$\sim$128 ${\mu}g/ml$. The chloroform soluble fractions of stem and ethanol extract of fruit showed significant cytotoxicity with $LC_{50}$ value of 0.94 ${\mu}g/ml$ and 0.49 ${\mu}g/ml$, respectively against brine shrimp larvae.