• Korean Journal of Food Science and Technology
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• v.14 no.2
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• pp.136-140
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• 1982

In order to evaluate the feasibility for the sterilization of Korean red and white ginseng powder by irradiation, red and white ginseng powder (120 mesh) was irradiated by 0.1, 0.3, 0.5, 0.7, 1.0 and 2.0 Mrad with $^{60}Co$ irradiator (dose rate: 4000 rad/h). Extraction rate of crude saponins by buthanol and by 50% ethanol were slightly increased according to the irradiation dose (buthanol ex. 1.7%, 50% ethanol ex. 2.6% at 1.0 Mrad irradiation. There are no remarkable changes in HPLC patterns of crude saponins by radiation. It was found that irradiation up to 1 Mrad on Korean ginseng products have no significant effect on proximate component, reducing sugar and amino nitrogen of ginseng powder and on the color density of ginseng extract with 50% ethanol. Irradiation up to 1 Mrad could be utilized for the sterilization of Korean ginseng powder whithout changes of physicochemical properties.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.293-299
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• 2002

This experiment was conducted to elucidate the effects of fruit bagging on the amounts of pesticide residues on/in pears with two pesticides, chlorpyrifos 25% WP, and penconazole 5% WP, and two pear cultivars, Niitaka and Hwangeum-bae. Residues of chlorpyrifos and penconazole in bagged pears were only $0.4{\sim}27%$ of those in non-bagged one. Residues of both pesticides in bagged and non-bagged pears were steeply reduced in the field but slowly reduced during storage. Residues of chlorpyrifos were more in the peel than in the flesh, while penconazole in bagged pear was evenly distributed in the peel and flesh. Chlorpyrifos was evenly distributed in outer bag and inner bag irrespective of bag materials, while most of penconazole was found in outer bag rather than in inner bag. To produce safer pear from pesticide residues, removal of bag before storage is recommended.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.84-93
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• 2013

Validated analytical methods for isopyrazam are meager or lacking. In the present study, a single residual analytical method was developed for isopyrazam in selected commodities. Isopyrazam was analyzed in brown rice, soybean, green pepper, mandarin, cucumber, and Korean melon. We tried different solvents and methods through extraction, partition and purification steps to obtain best analytical results. For isopyrazam samples were extracted with acetonitrile, concentrated and partitioned with n-hexane, clean-up using florisil with n-hexane/ethylacetate (70/30) and analyzed with HPLC/UVD. The limit of quantitation (LOQ) for isopyrazam was 1.0 ng (S/N > 10) and method LOQ (MLOQ) was 0.04 mg $kg^{-1}$. Recovery ranged through 81.0~105.3% (syn-isomer) and 80.8~105.6% (anti-isomer) at fortification level of 0.04 (MLOQ), 0.4 (10 ${\times}$ MLOQ), and 2.0 (50 ${\times}$ MLOQ). The coefficient of variation (CV) for isopyrazam was less than 10% regardless of sample types. These results were further confirmed with LC/MS, respectively. The proposed method is highly reproducible and sensitive and is suitable for routine analysis.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.272-279
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• 2010

KNF-1002, a new fungicide candidate, is very effective for protecting crops against plant diseases, but its curative activity against barley powdery mildew is negligible due to its weak penetrability into plant leaf. To select the most efficient activator and, at the same time, spreade-sticker, foliar uptake and deposit of aqueous spray formulations containing non-ionic or anionic surfactants and fatty acid alkyl esters as an adjuvant were assessed by using Congo Red method. In the absence of activator, only 0.1% of the applied active ingredient was absorbed by barley leaves 24 h after spraying with an aqueous acetone containing KNF-1002 100 mg/L. But, non-ionic surfactants (500 mg/L), such as heptaethylene glycol monooctadecenyl ether (OE-7), dodecaethylene glycol monohexadecyl ether (CE-12), so facilitated KNF-1002 uptake that the uptake was increased up to 48.5%. To wheat plant, the addition of surfactants in spray solution of KNF-1002 also increased the foliar uptake and deposition of active ingredient, but its efficiency varied according to the kind of fatty alcohol moiety of polyoxyethylene surfactant. KNF-1002 formulations containing nonaethylene glycol monododecyl ether (LE-9) as an activator and spreader-sticker showed remarkable increases of fungicidal activity against barley powdery mildew.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.3
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• pp.185-191
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• 2001

To obtain the basic information for degradation of remaining pesticide accumulated in cultivated soil of Honam area, the resistant bacterial strains were investigated in Chlorothalonil(TPN). Mancozeb, Bentazone, and Butachlor levels of 100, $500{\mu}g\;ml^{-1}$, and degradation of TPN by TPN-resistant bacteria in sterilized soil was studied under TPN levels 0, 10, 50 and $100{\mu}g\;g^{-1}$. A number of resistance strains were decreased with higher at concentration level of pesticide, and were higher in greenhouse than upland or paddy soil. The resistance of bacteria was strong in other of Bentazone> Butachlor> TPN> Mancozeb. The percentage of bacterial strains of resistance for pesticides isolated from the cultivated soil were the highest in Acinetobacter spp. and Corynebacterium spp., and the lowest in Moraxella spp. A number of TPN-resistant strains were the highest at the TPN level of $10{\mu}g\;g^{-1}$, and 5 days after strains inoculation, and were higher in Pseudomonas spp. TD-25 than TC-23 or strains in non-sterilized soil. The degradation of TPN was fast in order of strain TD-25>strain in non-sterilized soil >TC-23.

• Food Science and Preservation
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• v.16 no.2
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• pp.286-291
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• 2009

Microorganisms in seafood cooking drips were counted and identified. Total viable cell counts were 6.40 and 3.10 log CFU/g in cooking drips of Hizikia fusiformis and Thunnus thynnus, respectively. However, microbial populations fell with increased irradiation doses. In H. fusiformis cooking drips, a 5-log reduction in total aerobic bacteria was obtained by irradiation with 5 kGy. In T. thynnus cooking drips, however, contaminating microorganisms were more resistant to gamma irradiation and only a 1-log reduction was seen. DNA sequence analysis showed that the principal contaminating microorganisms in H. fusiformis and T. thynnus cooking drips were Lactobacillus and Bacillus species, respectively. Therefore, the high irradiation resistance of T. thynnus cooking drips microbes may result from spore formation by Bacillus species.

• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.35-41
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• 1979

Four to $17\%$ of the seeds of ginseng (Panax ginseng Meyer) collected from seemingly healthy plants carried Colletotrichum panacicola Nakata et Takimoto whereas the seeds from the plants with anthracnose sympotoms carried $42\%$ of the same fungus. Prevalent organisms isolated other than C. panacicola from seeds of both kinds of plants were Fusarium, Alternaria, Phoma, Trichoderma and others, ana in that order on acidified potato sucrose agar. C. panacicola also was isolated from 18 months old herbarium specimens. The fungus in the infected tissues also survived during the Korean winter months either on the soil surface or in the soil at 10 and 30 em in depth. When conidial suspensions of C. panacicola were inoculated on detached ginseng leaves, anthracnose symptoms occurred from 25 to $35^{\circ}C$. No symptoms occurred at temperatures below $17^{\circ}C$. Direct sunlight increased significantly the number of anthracnose lesions over those obtained in leaves inoculated in darkness or in 400 lux of fluorescent light. The lesions decreased as age of the leaves increased or as the number of conidia applied decreased. Optimum temperature for mycelial growth and conidial formation of C. panacicola was $25^{\circ}C$. Optimum pH for the mycelial growth was at $pH\;2.8\~4.6$ while the most conidial formation occurred at $pH\;5.2\~5.8.$. When fungicides were applied in the field to ginseng plants with a conidial suspension of C. panacicola, the most effective control of the anthracnose disease was by spraying with difolatan, and followed by maneb, zineb, captan and phaltan; Bordeaux mixture and ferbam were significantly less effective but significantly better than the inoculated control plants.

• Journal of Life Science
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• v.28 no.1
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• pp.110-115
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• 2018

This study was conducted to investigate the potential of medicinal plants as oral health materials derived from natural products. Among the extracts from 200 medicinal plants grown in Nepal, Laos, Mongolia, Bangladesh, Vietnam, and China, stem extracts from Diospyros malabarica (1 mg/disc) showed the highest antibacterial activity against Porphyromonas gingivalis ATCC33277 and Streptococcus mutans ATCC25175. The D. malabarica stem extracts showed antibacterial activity similar to chlorhexidine, sodium lauryl sulfate, and triclosan, which were used as a positive control, as well as higher antibacterial activity against S. mutans ATCC25175 than P. gingivalis ATCC33277. The D. malabarica stem extracts showed bactericidal action (MBC, 0.4 mg/ml) against P. gingivalis ATCC33277 and bacteriostatic action against S. mutans ATCC25175. The biofilm production rate of S. mutans ATCC25175 and the expression of the comX gene associated to biofilm formation in the cultures treated with 0.2-1.0 mg/ml of D. malabarica stem extracts were suppressed in a concentration-dependent manner. Based on the above results, it can be concluded that D. malabarica stem extracts can be used as oral health material derived from natural materials, as demonstrated by the bacteriostatic action and inhibition of biofilm formation against S. mutans ATCC25175.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.281-288
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• 2009

The strobilurin fungicides, azoxystrobin and kresoxim-methyl, were investigated to know the biological half-lives and dissipation patterns in Korean melon under plastic film house condition. Used pesticides for field application were 20% azoxystrobin of suspension concentrate and 47% kresoxim-methyl of water dispersible granule. Two pesticides were sprayed at recommended and double dose rate. Pesticide residues in Korean melon were analyzed until 14 days after application. The azoxystrobin was analyzed by HPLC equipped with UV detector after cleanup with florisil glass column. Initial residue concentrations of azoxystrobin in Korean melon at recommended and double dose rate were 0.09 mg/kg and 0.14 mg/kg, respectively. Those were less than 0.2 mg/kg maximum residue limit of Korean melon established by KFDA. The biological half-lives of azoxystrobin in Korean melon were 4.7 days at recommended dose rate and 7.8 days at double dose rate. Initial concentrations of kresoxim-methyl which was analyzed by GLC-ECD in Korean melon at recommended and double dose rate were 0.10 mg/kg and 0.23 mg/kg, respectively. Those were less than 1.0 mg/kg, MRL. The biological half-lives of kresoxim-methyl in Korean melon were 4.1 days at recommended dose rate and 4.8 days at double dose rate. The residue amounts of both pesticide was lower than MRL and biological half-lives were not so long. Because the weight of Korean melon under plastic film house condition was fast increased during cultivation.

• Journal of fish pathology
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• v.18 no.2
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• pp.167-178
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• 2005

Streptococcus iniae is one of the major bacterial pathogens of cultured olive flounder, Paralichthys olivaceus in Korea. This study was carried out to investigate the interaction between morphological characteristics and immune response such as phagocytosis and serum killing activity. They were differentiated phenotypically into two groups, the viscous colonies and the non-viscous colonies, but the strains in both groups were similar in physiological and biochemical characteristics. Electron microscopic examination of the viscous form revealed thick, electron-dense exopolysaccharide materials surrounding polycationic ferritin-stained cells, while the exopolysaccharide material was absent around the non-viscous form of S. iniae. The viscous type strains were disclosed more virulent than those of non-viscous type for olive flounder. The viscous strains were resistant to normal serum killing activity, while the non-viscous strains were susceptible to bactericidal activity of normal serum from olive flounder. The viscous strains were more resistant to opsonophagocytosis and decreased the chemiluminescence response of head kidney macrophages of olive flounder. All of the tested non-viscous S. iniae strains were efficiently destroyed by the macrophage after phagocytosis. Both the viscous and the non-viscous strains invaded and replicated in cultured fish cell line (CHSE-2l4). This cellular invasion may contribute to the pathogenesis of invasive S. iniae infection.