• Korean Journal Plant Pathology
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• v.12 no.4
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• pp.407-414
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• 1996

벼 담수직파재배에서 Pythium arrhenomanes 1398에 의한 벼목썩음병의 발병 억제효과가 높은 biological control agent를 배지와 growth chamber 검정을 통하여 선발하고 생물학적 방제 효과를 온실에서 검정한 결과 공시한 66 세균 중 91-110 균주에 의해서만 벼모썩음병의 발병이 억제되었다. CMA 배지 검정에서는 P. arrhenomanes 1398 균주만을 접종한 볍씨는 100% 발병율을 보인 반면 91-110 균주와 P. arrhenomanes 1398 균주를 함께 처리한 경우에는 25.0%가 발병되었으며, 이 효과는 metalaxyl을 처리한 볍씨에서의 21.7% 발병율과 유사하였다. Growth chamber 검정에서는 P. arrhenomanes 1398 균주만을 접종한 볍씨는 27.7% 모 출아율을 보인 반면 91-110 균주와 함께 처리하면 59.1%가 출아되었다. 그러나 91-110 균주에 의한 발병 억제효과는 50% household bleach로 표면 소독한 볍씨에서만 인정되었으며, 이 소독한 볍씨를 91-110 균주의 세균 부유액에 침지하여 3시간 진탕한 후 그 부유액을 따라내고 24시간 배양한 것이 진탕하지 않고 배양한 것에 비하여 모출아율이 54.3%에서 65.7%로 증가되었다. 91-110 균주와 P. arrhenomanes 1398 균주를 함께 처리한 볍씨의 출아율은 62.3%로서 P. arrhenomanes 1398 균주만을 접종한것의 30.8%에 비하여 높았다. 이상과 같이 담수직파한 벼모썩음병의 발병 억제효과가 높은 91-110 균주는 Bacillus brevis로 동정되었다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.179-185
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• 2005

Polycyclic aromatic hydrocarbons (PAHs) are a kind of toxic environmental pollutants and has been accumulated usually in marine sediments. Due to their potential hazardous to human, removal of PAHs from environments has been great concern. In the present study, the effect of microbial inoculation and the supplementation of mixed form cyclodextrin (M-CD) was assessed in the pre-sterilized or nonsterilized microcosms for optimizing operational conditions for ex situ bioremediation of sediments contaminated by PAHs. Activity of electron transport system (ETSA) was increased by the addition of M-CD regardless of inoculation of microorganisms in microcosms without sterilization. The degradation rate of PAHs in sterilized microcosms was app. 9-20% by the inoculation of single strain and 24-37% by the inoculation of microbial consortium supplemented with 1% M-CD, respectively. The degradation was not observed in microcosms without sterilization under the same conditions. The proportion of inoculated microorganisms also decreased in nonsterilized microcosms. Signals of inoculated bacteria were decreased to detection limit after 2 days in the microcosms without M-CD. In conclusion, microbial inoculation with appropriate carbon sources and removal of natural flora and grazers are required for the efficient ex situ bioremediation of sediments contaminated by PAHs in bioslurry reactor.

• Biomedical Science Letters
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• v.3 no.2
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• pp.77-82
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• 1997

One of the most important prerequisites of the industrial microorganism is that it should not be virulent to humans or economically important animals or plants. In this investigation, the microbiological characterization of T. madida N-5-3 strain was performed. And then, the virulence of the test strain in mouse model was examined systematically. The microbiological characteristics of the test strain were found to be fully consistent with those of typical T. madida. The i.p. lethal dose(LD)$_{50}$ of the test strain was greater than 1$\times$10$^8$, because there was no dead animal with the challenge doses upto the level of 1$\times$10$^8$. When 1$\times$10$^8$ yeast cells were challenged to the laboratory mice, T. madida N-5-3 strain was completely cleared from the liver and spleen in 4 days after challenge. And no pathological changes in the histological examination of the internal organs from challenged mice was observed. Above results can provide the predictability of the safety of T. madida N-5-3 strain for the industrial use in the view point of the public health aspect.

• Research in Plant Disease
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• v.13 no.1
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• pp.45-49
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• 2007

Single spores were isolated from infected roots of Chinese cabbage with a typical clubroot symptom, collected from different Chinese cabbage cultivation areas in Korea. When the single spore isolates were inoculated on Chinese cabbage, radish, turnip, kale, leaf mustard and Williams' differential varieties, among 321 roots harvested two weeks after inoculation, a visual symptom was observed on only one root and light/uncommon symptoms were done on 70 roots. These 71 individuals were homogenized and used as inocula. These inocula caused generally higher pathogenicity than that of single spore. Finally 15 isolates, with enough growth for conducting further experiment, were selected. These 15 individuals were grouped four, seven, two and two into race 1, race 4, race 9 and race 11, respectively, using Williams' differential set. It was confirmed that race 4 were dominantly present in Korea. These 15 had been obtained from roots of Chinese cabbages, radishes and turnips inoculated with single resting spores and had shown pathogenicity to Laurentian and Wilhelmsburger belong to Rutabaga in Williams' differential variety set. Therefore, we assume that such characteristic pathotypes including race 4, especially, of P. brassicae showing strong pathogenicity to Chinese cabbage, radish and turnip may be dominant in Korea.

• Korean journal of applied entomology
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• v.15 no.4 s.29
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• pp.163-168
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• 1976

The present study was conducted to determine the number of genes controlling resistance of variety Tongil to three prevalent blast strains and any relationships among the genes in the inheritance of resistance of the variety to blast. Tongil was crossed with five local varieties and the progenies were tested with blast isolates E-7 and 100-14 by injection inoculation method. Results indicated that a tingle dominant gene conditioned resistance of variety Tongil and resistance to the isolate E-7 was controlled by a gene different from that controlling resistance to the isolate 100-14. In previous study it was identified that the gene controlling resistance to the isolate E-7 was different from the gene for resistance to isolate T-1. Therefore based on the foregoing results it may be inferred that the variety Tongil has at least three or more resistant genes to blast.

• Korean journal of applied entomology
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• v.19 no.1 s.42
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• pp.21-29
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• 1980

In the present study, it was found that the susceptible variety Khao-tah-haeng 17, at all four predisposing temperature regimes, produced more typical lesions than hypersensitive lesions when inoculated with most of the blast fungus isolates. Tetep, Carreon, IR36 and Sensho produced more hypersensitive lesions than typical lesions at all four predisposing temperature regimes. Highly significant differences among predisposing temperature regimes and rice varieties for number of hypersensitive lesions and number of typical lesions were found. Symptom occurrence on a specific variety, as measured by the number of typical lesions, was more affected by predisposition temperature or blast isolate than by temperature and isolate combined. Symptom occurrence on a specific variety, as measured by the number of hypersensitive lesions, was more affected by blast isolate than by predisposition temperature.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.137-141
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• 1996

오이에서 분리한 비병원성 Fusarium oxysporum 균주 4-1은 온실에서 오이에서 선접종하였을 때 덩굴쪼김병에 안정적인 방제효과를 보여 세 번의 시험에서 그 방제가가 67~100%에 달하였다. 이 균주는 접종후 90일에도 오이 뿌리에서 높은 빈도로 재분리 되었으며 g 토양당 분생포자 농도가 10\ulcorner개 이상의 높은 농도로 접종하였을 때는 뿌리의 갈변현상을 초래하였다. 1993년부터 1995년에 걸친 세 번의 포장시험에서 이 균주는 오이덩굴쪼김병의 발생을 무처리 발병율 56%, 11%, 35%에 비해 18%, 1%, 8%로 각각 억제하였다.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.447-453
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• 2007

With a broad objective for the development of microbial based fertilizers, a total of 373 strains were isolated from rhizoplane and rhizosphere of pepper, tomato, lettuce, pasture, and grass. The efficacy of the isolates to augument overall plant growth was evaluated. After screening for their plant growth promotion and antagonistic properties in vitro efficient strains were further selected. The most efficient strains was characterized by 16S rRNA gene sequences and biochemical techniques and was designated as Bacillus subtilis S37-2. The strains facilitated plant growth and inhibited the plant phathogenic fungi such as Fusarium oxysporum (KACC 40037, Rhizoctonia solani (KACC 40140), and Sclerotinia sclerotiorum (KACC 40457). Pot based bioassay using lettuce as test plant was conducted by inoculating suspension ($10^5$ to $10^8cells\;mL^{-1}$) of B. subtilis S37-2 to the rhizosphere of lettuce cultivated in soil pots. Compared with non-inoculated pots, marked increase in leaf (42.3%) and root mass (48.7%) was observed in the inoculation group where the 50ml of cell mixture ($8.7{\times}10^8cells\;ml^{-1}$) was applied to the rhizosphere of letuce either once or twice. Antagonistic effects of B. subtilis S37-2 strain on S. sclerotiorum (KACC 40457) were tested. All the tested lettuce plants perished after 9 days in treatment containing only S. sclerotiorum, but only 17% of lettuce was perished in the inoculation plot. B. subtilis grew well in the TSB culture medium. The isolates grew better in yeast extracts than peptone and tryptone as nitrogen source. The growth rate was 2~4 times greater at $37^{\circ}C$ as compared with $30^{\circ}C$ incubation temperature. B. subitlis S37-2 produced $0.1{\mu}g\;ml^{-1}$ of IAA (indole 3-acetic acid) in the TSB medium containing L-tryptophan($20mg\;L^{-1}$) in 24 hours.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.1
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• pp.55-60
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• 1988

To develop soybean inoculant the effects of inoculation with selected Rhizobium japonicum strains were tested in the field, and the results were as following. 1. With the inoculation of selected strains, increase of nodule number, nodule weight and nitrogen fixing activity were observed with or without applying N-fertilizer. 2. Chlorophyll contents was increased and senescence of plant was delayed with the inoculation of selected strains in case without applying N-fertilizer. But there was little difference of chlorophyll contents in case with applying N-fertilizer. 3. There were little differences of plant height and number of nodes, and some increase of plant stem dry matter and number of pods with inoculation of selected strains. 4. The mean yield of inoculation group (363-374kg/10a) was increased by 8-11% comparing to the uninoculated group (337kg/10a) in case without applyiag N-fertilizer. The mean yield of inoculated group (368-384kg/10a) was increased by 9-14% also in case with applying N-fertilizer.

• Journal of Veterinary Clinics
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• v.28 no.3
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• pp.297-302
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• 2011

Avian pathogenic Escherichia coli (APEC) causes a number of extraintestinal diseases in poultry. A virulence factor, P-fimbriae is firmly associated with the diseases. In this study, to develop an effective vaccine for the prevention of APEC, recombinant attenuatted Salmonella Typhimurium vaccines expressing PapA and PapG of P-fimbriae were evaluated whether these induced protective immune responses in murine models. Female BALB/c mice were primed and boosted orally at 7 and 10 weeks of age. In all immunized mice, the antigen-specific serum IgG levels were remained higher than those in the control mice from the fourth week post inoculation till the end of this study. In addition, antigen-specific serum IgG levels in the prime-booster immunized mice were enhanced as compared to the single immunized mice among each immunized group. The antigen-specific mucosal IgA levels in the mice immunized with each strain also induced higher than those in control mice. In addition, serum IgG and fecal IgA levels in mice administered with the combination of both strains were highly induced compared to those in mice immunized with each strain alone. These results indicated that PapA and PapG worked together for inducing high immune responses. To partly discern the nature of immunity induced by the strains, we quantified serum IgG subtypes IgG1 and IgG2a specific to antigens. The PapA and PapG strains biased the immunity to the Th1-type, as determined by the IgG2a/IgG1 ratio. On the other hand, the immunization with the both strains in combination produced mixed Th1- and Th2-type immune responses. These indicated that immunization with the combination of PapA and PapG could elicit both humoral and cell-mediated immunities.