• Microbiology and Biotechnology Letters
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• v.14 no.4
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• pp.329-334
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• 1986

Bacillus thuringiensis serovar israelensis H 14 strain was cultured in 4 different fermentation M-media and then measured the rates of their growths and the productions of endotoxin crystals front the media. Out of the four M-media the production of endotoxin crystals and spores was maximal in M-4 medium (pH 9). The wet weight of the cells grown in the 150$m{\ell}$ culture was approximately 3.901g and the number of viable spores was 1.53$\times$10$^{12}$ per nil and the ratio of the endotoxin over the total cell weight was 18.54%. The generation time was about 89.3 minutes in the M-1 medium, 124.1 minutes in the M-2, 97 minutes in the M-3, 130.8 minutes in the M-4. The proper pHs for the production of the endotoxin appeared to be 6.5 to 7.5.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.233-236
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• 2000

Bacillus thuringiensis (Bt) is the most widely used microbial insecticide in the biological control market. Cultivation of the microorganism to high cell densities offers potential for enhancing the rate of formation as well as the concentration of the desired products In the fermentation broths in bioreactor. With this objective, we developed the new bioreactor incorporating ceramic membrane module for the retention of cell mass. Cell yield and spore formation of Bacillus thuringiensis was improved markedly by adopting this new bioreactor based on glucose -limited feeding operation. It was possible to grow the cell and the heat-resistant spore to above $1.2\;{\times}\;10^{10}\;CFU/ml$ density. With glucose-limited operation, we studied the growth behavior of Bacillus thuringiensis during the cell retention culture. Linear growth of Bacillus thuringiensis was observed under glucose-limited culture, which matched well with simple mathematical model of cell retention culture.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.4
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• pp.375-385
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• 1987

This study was carried out to investigate the effects of pesticides on soil respiration, microflora and enzymes in loam soil, and on pathogenic microorganisms in continuous pepper cropping soil. The results are summarized as follows. No significant effect of pesticides on soil respiration was shown, with the exception of propoxur which slightly increased at $10{\mu}g\;g^{-1}$ treatment. When pesticides were treated, the amount of soil microorganisms generally decreased at the early stage of incubation and the number of microflora was much more decreased at 60-day incubation. When pesticides were treated, the amount of soil enzyme activity was inhibited at the early stage of incubation and gradually recovered at the last stage of incubation. The amount of polygalacturonase activity was increased at the 20-and 30-day incubation in propoxur treatment plot. The amount of ${\beta}$-glucosidase and dehydrogenase activity was increased at 20-and 60-day incubation in carbofuran and acephate treatment plot. The amount of phosphatase activity was increased at 60-day incubation in propoxur and isoprocarb treatment plot. The amount of Fusarium generally decreased in continuous pepper cropping soil, with the exception of isoprocarb and acephate treatment plot which significantly increased. The amount of Pythium increased at 60-day incubation with the exception of captan treatment plot which significantly decreased.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.101-108
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• 2022

Because of their specificity to target insects and relatively low toxicity to non-target organisms, insect growth regulators (IGRs) have been regarded as attractive alternatives to chemical insecticides. Commercially available IGRs are classified into juvenile hormone agonists (JHAs), ecdysone agonists (EAs), and chitin synthesis inhibitors (CSIs) according to their mode of action. Recently, JH-mediated interaction of methoprene-tolerant (Met), which is JH receptor, and its binding partners have been replicated in vitro using yeast cells transformed with the Met and FISC/CYC genes of A. aegypti. Using this in vitro yeast two-hybrid β-galactosidase assay, juvenile hormone antagonists (JHANs) have been identified from various sources including chemical libraries, plants, and microorganisms. As juvenile hormone (JH) is an insect specific hormone and regulates development, reproduction, diapause and other physiological processes, JHANs fatally disrupt the endocrine signals, which result in abnormal development and larval death. These results suggested that JHANs could be efficiently applied as IGR insecticides with a broad insecticidal spectrum. This review discuses JH signaling pathway mediated by Met and future prospects of JHANs as environmentally benign IGR insecticides.

• Journal of Life Science
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• v.12 no.3
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• pp.369-373
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• 2002

The waste-water from the industry for production of a soybean curd (the soybean curd waste-water) was investigated to use for the substrate to produce the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1 used as one of well known microbial pesticides. The pH of the soybean curd waste-water was 9.8 and its chemical oxygen demand (COD), total nitrogen (TN) and phosphate (TP) were 276.0, 71.1 and 5.5mg/$\ell$, respectively. The higher was the concentration of the soybean curd waste-water in the medium, the more endotoxin was produced. Maximal sporulation occurred at which concentration of $K_2$HPO$_4$in the medium supplied with the soybean curd waste-water was 1% (w/v). Production of the endotoxin with the optimized medium supplied with the soybean curd waste-water was 1.5 times higher than that without the soybean curd waste-water. The soybean curd waste-water was found to be suitable substrate for production of the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1.

• Korean Journal of Microbiology
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• v.35 no.1
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• pp.61-64
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• 1999

Organophosphorus inseclicide phosphamidon-degrading bacteria were isolated from agricultural soils and identified using Biolog microtiter assay. All Gram-positive degrading bacterial strains belong to genus Bacillus and many Gram-negative bacteria were rare soil species. Among them fast growing strains on phosphamidon-containing minimal medium were sclected and their biodegrading capability wcre measured. YD-17 which was identified as Capnocytophaga gingivalis showed the highest biodegradation rate. It could incrcase the removal of phosphamidon up to 52%. During the biodegradation continuous increase of amount of cell protein was observed, which indicated that phosphamidon was utilized as a carbon source for phosphamidon-degrading bacteria.

• Korean Journal of Environmental Agriculture
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• v.17 no.3
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• pp.220-226
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• 1998

The effects of metalaxyl(granule), carbofuran(granule) and simazine(water soluble powder) on the soil microflora were conducted at field soil between Iksan and Chonju province. Pesticides were divided into 0.5, 1, 1.5 and 2.0 times of normal of field, respectively. The number of fluorescent Pseudomonas was ranged from $10^3$ to $10^6/g$ in both field soil treated with cabofuran. Pseudomonas concentration of Chonju field soil slowly increased and approached the maximum level at 56 day after treatment(DAT). It showed the higher at 14DAT than other DAT in Iksan field soil treated with metalaxyl or simazine, whereas it increased again at 112 DAT in metalaxyl treatment. Cabofuran treatment of both field soil showed maximum Pseudomonas number at 28 DAT compared to that of other treatments. In Chonju field soil, those Pseudomonads of metalaxyl and simazine treatment increased the highest level at 7 DAT. Simazine treatment decreased it's number from the beginning of experiment. In both soil, metalaxyl treatment decrease the general fungi number at 7 DAT, but increase at 14 and 56 DAT in Iksan field soil. However it increased at 56 DAT in Chonju field soil. Cabofuran treatment of Iksan field soil tended to decrease general fungi number at 28 DAT, but was ranged from 1.0 to $8.6{\times}104/g$ for the rest of experimental period. It started to increase at 56 DAT simazine treatment of Iksan. General bacterial concentration both soil treated with cabofuran was belong to $26.6{\sim}29.6{\times}106$. It was the highest at 56 DAT, but was not significantly different. General actinomyces number was highly increased at 7 and 112 DAT compared to that of other DAT. Pseudomonas putida or P. fluorescens from both field soil was separated and identified 10 to 30 of all 104 Pseudomonas, respectively. All isolated microorganisms showed chemical resistance of 100ppm metalaxyl, cabofuran and simazine treatment.

• Food preservation and processing industry
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• v.16 no.2
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• pp.10-23
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• 2017

최근 햄버거 병을 시작으로 살충제 계란파동, E형간염 소시지까지, 급증한 식품안전 사고는 국민식품소비를 위축시키고 막연한 공포감 조성으로 올바른 식품섭취를 유지할 수 없도록 한다. 국민소득 증가와 더불어 식품의 안전성에 대한 소비자의 관심이 높아지고 있으며, 소비자는 보다 안전한 먹거리를 공급해줄 것을 요구하고 있다. 이에 대한 대응책을 마련하고자 정부와 식품업계, 학계 등은 고심하고 있다. 본 연구는 4차산업혁명에 발맞추어 식품안전분야에 ICT기술을 활용한 생산에서 소비자까지의 식품공급망의 안전관리를 체계화하는 FSMS(Food Safety Management System)을 구성해보고 그를 통한 식품의 안전도를 시험분석을 통해 효과를 검증하는 것이 목적이다. 본 연구는 FSMS의 기술요소인 빅데이터, 온습도IoT센서 등을 Pilot Test하고 FSMS 도입전과 도입후의 검체를 체품하여 공인식품시험검사기관에서 검체의 미생물수 분석을 통해 최종적으로 FSMS의 도입효과와 모형도를 제시하였다.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.387-390
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• 2012

Beet armyworm (Spodoptera exigua), diamondback moth (Plutella xylostella) and tobacco cutworm (S. litura) are insect pests causing damage in many economically important vegetables in Korea. Bacillus thuringiensis, commonly known as Bt, has been available as an alternative insecticide for many years. Five commercial Bt products and the mixtures evaluate the control efficacy against three kinds of moths. These commercial Bt products had high control efficacy against $2^{nd}$ instar of diamondback moth, but didn't show high mortality against beet armyworm and tobacco cutworm. Mixtures of Bt products didn't have synergistic effects to the tested moths. Also application of twice and four times the recommended concentration didn't improve the control effects against the tested three species of moths.

• Korean Journal of Environmental Agriculture
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• v.2 no.2
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• pp.65-72
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• 1983

The effects of soil factors, pesticide application levels and environmental factors on the degradation of two carbamate insecticides, BPMC and carbofuran, in soil were studied under flooded and non-flooded conditions. The degradation patterns of BPMC or carbofuran were similar in flooded and non-flooded soils. It was also found that carbofuran was more persistent than BPMC in the test soil. Regards to organic contents of soils, high contents of organic matter reduced degradation of either BPMC or carbofuran and high soil pH accelerated degradation of both insecticides. Soil microorganisms seem to play an important role in the degradation of BPMC and carbofuran. Both chemical and biological degradations appear to contribute transformation of BPMC and carbofuran in the flooded soil.