• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.91-96
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• 1998

For the expression of the cry11Aa gene highly toxic to dipteran insects, we constructed two cyanobacteria-Escherichia coli(E. coli) shuttle vectors, pCYASK5-l and pCYASK5-2. These vectors were transformed into E. coli and selected with kanamycin. The expression of the cry11Aa gene in E. coli was characterized by SDS-polyacrylamide gel electrophoresis and Western blot analysis. Two E. coli transformants harboring pCYASK5-1 and pCYASK5-2 expressed the cry11Aa gene in size of 72 kDa and 64 kDa, respectively and showed over 89% mortality against Culex pipiens larvae.

• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.39-44
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• 2011

The changes in major moth populations were monitored by sex pheromone traps in pear orchards at Yuseong-Gu, Daejeon from 2008 to 2010. Among four major moths, Grapholita molesta and Caposina sasakii occurred most frequently. Their occurrences peaked 2 to 3 times during the growing season from May to September. G. molesta was exceptional, occurring until September. For the environmentally-friendly control of these moths, 9 control materials including insect pathogenic bacteria and environmentally-friendly agricultural materials, were examined on the larva of 4 kinds of moth and sprayed on pear leaves in the field. As the generalized results of bioassay, Bacillus thuringiensis subsp. kurstaki and Sophora flavescens extract were shown to have better control effects than any other control material.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.827-841
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• 2019

The effect of genetically engineered rice Bt-9 on the diversity and abundance of plant-dwelling insects and spiders was tested under field conditions. Genetically engineered rice Bt-9, expressing mCry1Ac1 from Bacillus thuringiensis, confers resistance to rice leaf roller (Cnaphalocrocis medinalis) and provides tolerance to the herbicide glufosinate (PPT). The study compared Bt-9 and two non-GM reference varieties, Ilmi-byeo and Dongjin-byeo, at LMO isolated fields in Gunwi (Kyungpook National University) and Jeonju (National Institute Agricultural Sciences) in Southern Korea in 2016 - 2017. A total of 40,817 individuals from 62 families and 11 orders were collected from the two living modified organism (LMO) isolated fields. From the three types of rice fields, a total of 13,982, 14,105, and 12,730 individuals from the Bt-9, Ilmi-byeo and Dongjin-byeo were collected, respectively. Throughout the study, the analysis of variance indicated no significant differences (p < 0.05). Multivariate analysis showed that the abundance and diversity of plant dwelling insects were similar. The data on insect species population densities were subjected to principal component analysis (PCA), which did not distinguish among the three varieties, Bt-9 and the non-GM, reference cultivars, during the cultivation years. However, the results of the PCA analysis were completely divided into four groups based on the yearly survey areas. Therefore, there was no evidence for a negative impact of Bt-9 on the above-ground insects and spiders.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1996.12a
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• pp.70-70
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• 1996

The cytotoxicological effect of Bt 1-endotoxin, well-known as a bioinsecticide, was investigated on ion channel of insect cell lines. This study attempted to evaluted the specificity by simple experiment to measure the cell swelling using lepidopteran cell lines in isotonic solution containing only one cation. Cell swelling was stimulated in KCI-sucrose isotonic solution as well as TC-100 media containg in solubilized crystal 5-endotoxin. It suggested that the cell swelling by Bt toxin have a relation to K+ channel. The cell swelling may be due to the stimulation K+ influx and simultaneously the penetration of H2O induced by Bt toxin, because the stimulation of swelling was observed with the solubilized toxin in KCI-sucrose isotonic solution, but not in sucrose isotonic solution. Moreover the specific K+ channel blocker, such as 4-arnjnopyrimidine(4-AP) and ouabain, showed the significant effect on the cell swelling induced by Bt toxin. The increasement of the cell swelling induced by 4-AP suggested to be caused by the block of K+ efflux through K+ leak channels. The inhibition of cell swelling by ouabain, which is the well-known inhibitor of Na+, K+-ATPase, suggested to be due to decreasement of K+ influx following diminishment of Na+, K+-ATPase activities.

• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.59-63
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• 2012

Bovine serum contains various nutrients and growth factors that can be potentially used in biological experiments, drug manufacturing process and food industry. However, almost all the bovine blood has been wasted during slaughter process in Korea, thus there is a high demand for alternative uses of the wasted sera. In order to produce high quality and safe sera, it is necessary to screen zoonotic pathogens as well as other microbial contaminants to prevent any downstream contamination. The present research has been undertaken to assess biological safety of Hanwoo sera by determining microbiological contamination during slaughtering and handling processes. Serological tests have been performed to detect bacteria, mycoplasma and virus contamination in total of 52 Hanwoo sera. No sera were found to be contaminated with mycoplasma or virus, but only two sera were found to be contaminated with Bacillus thuringiensis. The present result shows that Hanwoo sera obtained from slaughtering process are biologically safe and have potentials to be developed as a biological reagent. Moreover, the methods employed in our study may provide basic standard for microbiological screening methods once wasted Hanwoo sera gain industrial values.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.181-188
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• 2016

BtPlus is a group of biopesticides that are made of Bacillus thuringiensis and immunosuppressant. A new BtPlus that exhibits high insecticidal activity against mosquito larvae has been investigated in control efficacy in field conditions and its environmental safety against aquatic system. This study assessed the control efficacy of BtPlus against mosquito larvae with two different application methods. In aerial spraying application (100 mL per $3.3m^2$), BtPlus was effective at 50% or above formulation concentrations to control mosquito larvae. For a direct application to aqueous mosquito habitat, a semi-field mimicking paddy rice field was constructed. In this condition, BtPlus showed 80% and 100% control efficacies at 0.1% and 0.2% concentrations, respectively. BtPlus also showed 40% mortality against adults at 0.1% concentration in 10% sugar bait. However, its control efficacies against adults were much less than against larvae. Safety assessment of BtPlus against ecosystem was evaluated using young carp (Cyprinus carpio), a water flea (Daphnia magna), and a honey bee (Apis mellifera). BtPlus did not give any adverse effects on these nontarget organisms. Based on these results, BtPlus can be applied to control mosquitoes by direct aqueous application to paddy rice field.

• Research in Plant Disease
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• v.21 no.4
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• pp.280-289
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• 2015

Maize (Zea mays L.) is an economically important crop in worldwide. While the consumption of the maize is steadily increasing, the yield is decreasing due to continuous mono-cultivation and infection of soil-borne fungal pathogens such as Fusarium species. Recently, stalk rot disease in maize, caused by F. subglutinans and F. temperatum has been reported in Korea. In this study, we isolated bacterial isolates in rhizosphere soil of maize and subsequently tested for antagonistic activities against F. subglutinans and F. temperatum. A total of 1,357 bacterial strains were isolated from rhizosphere. Among them three bacterial isolates (GC02, GC07, GC08) were selected, based on antagonistic effects against Fusarium species. The isolates GC02 and GC07 were most efficient in inhibiting the mycelium growth of the pathogens. The three isolates GC02, GC07 and GC08 were identified as Bacillus methylotrophicus, B. amyloliquefaciens and B. thuringiensis using 16S rRNA sequence analysis, respectively. GC02 and GC07 bacterial suspensions were able to suppress over 80% conidial germination of the pathogens. GC02, GC07 and GC08 were capable of producing large quantities of protease enzymes, whereas the isolates GC07 and GC08 produced cellulase enzymes. The isolates GC02 and GC07 were more efficient in phosphate solubilization and siderophore production than GC08. Analysis of disease suppression revealed that GC07 was most effective in suppressing the disease development of stalk rot. It was also found that B. methylotrophicus GC02 and B. amyloliquefaciens GC07 have an ability to inhibit the growth of other plant pathogenic fungi. This study indicated B. methylotrophicus GC02 and B. amyloliquefaciens GC07 has potential for being used for the development of a biological control agent.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.319-327
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• 2016

Chemical pesticides have been used to control persimmon pests, however the overuse of the pesticides caused insect resistance, followed by failure in pest management and residual problems. Herein we investigate the potential of eco-friendly organic pesticides (EFOP) on the control persimmon pests, Stathmopoda masinissa (persimmon fruit moth) and Riptortus pedestris (bean bug). Ten commercially available plant-derived organic pesticides and one microbial pesticide were sprayed on the target insects in laboratory conditions. The chemical pesticide, buprofezin+dinotefuran wettable powder served as a positive control. In the first bioassay against persimmon fruit moth, alternatively Plutella xylostella larvae were used due to the lack of persimmon fruit moth population from fields, and three organic pesticides showed high control efficacy, such as pyroligneous liquor (EFOP-1), the mixture of Chinese scholar tree extract, goosefoot and subtripinnata extracts (EFOP-2) and Bacillus thuringiensis subsp. aizawai NT0423 (EFOP-11). When the three selected organic pesticides were treated on the persimmon fruit moths, the EFOP-2 treatment showed the highest control efficacy: 27.7% (5 days), 13.3% (7 days) and 6.7% (10 days) of survival rates. In the bioassay against bean bugs, the mixture of Chinese scholar tree, goosefoot and subtripinnata extracts (EFOP-2 and EFOP-9) and the extracts of sophora and derris (EFOP-10) showed high control efficacy, particularly the highest in the treatment of EFOP-2: 20.0% (5 days) and 16.7% (10 days) of survival rates. These results suggest that the mixture of Chinese scholar tree, goosefoot and subtripinnata extracts (EFOP-2) has high and multiple potential in the management of the persimmon pests.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.293-301
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• 2010

The feasibility of two strategies for transgene pyramiding using Agrobacterium-mediated transformation was investigated to develop a transgenic potato (Solanum tuberosum L. cv. Iwa) with resistance to potato tuber moth (PTM) (Phthorimaea operculella (Zeller)). In the first approach, cry1Ac9 and cry9Aa2 genes were introduced simultaneously using a kanamycin (nptII) selectable marker gene. The second approach involved the sequential introduction (re-transformation) of a cry1Ac9 gene, using a hygromycin resistance (hpt) selectable marker gene, into an existing line transgenic for a cry9Aa2 gene and a kanamycin resistance (nptII) selectable marker gene. Multiplex polymerase chain reaction (PCR) confirmed the presence of the specific selectable marker gene and both cry genes in all regenerated lines. The relative steady-state level of the cry gene transcripts in leaves was quantified in all regenerated lines by real-time PCR analysis. Re-transformation proved to be a flexible approach to effectively pyramid genes for PTM resistance in potato, since it allowed the second gene to be added to a line that was previously identified as having a high level of resistance. Larval growth of PTM was significantly inhibited on excised greenhouse-grown leaves in all transgenic lines, although no lines expressing both cry genes exhibited any greater resistance to PTM larvae over that previously observed for the individual genes. It is anticipated that these lines will permit more durable resistance by delaying the opportunities for PTM adaptation to the individual cry genes.

• Korean journal of applied entomology
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• v.48 no.3
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• pp.385-392
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• 2009

Two entomopathogenic bacteria, Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata, are known to be potent against the diamondback moth, Plutella xylostella, when the bacteria are injected into the hemocoel. This study investigated any pathogenic effect of their culture broth on P. xylostella by oral administration. Only culture broth of both bacterial species did not give enough pathogenic effects by the oral administration. However, when the culture broth was orally treated together with Bacillus thuringiensis (Bt), both cell-free culture broth significantly enhanced Bt pathogenicity against the 3rd instar larvae of P. xylostella. The culture broth was then fractionated into hexane, ethyl acetate, and aqueous extracts. Most synergistic effect on Bt pathogenicity was found in ethyl acetate extracts of both bacterial species. Thin layer chromatography of these extracts clearly showed that ethyl acetate extracts of both bacterial culture broths possessed metabolites that were different to those of hexane and aqueous extracts. These results suggest that the both entomopathogenic bacteria produce and secrete different factors to give significant synergistic effect on Bt pathogenicity.