In this study, an attempt was made to approximate the main characteristic values of Bi0.5(Na0.78K0.22)0.5TiO3 (= BNKT) depending on the content of Fe2O3 additives, aiming to approach the values of lead(Pb) piezoelectric ceramic materials (PZT). Specifically, when the piezoelectric coefficient (d33) value of lead(Pb) piezoelectric ceramic material (PZT polycrystalline ceramic powder) is 300[pC/N] or higher, it is applied for hard purposes such as ultrasonic welding machines and cleaning machines, and when it exceeds 330[pC/N], it is applied for soft purposes like piezoelectric sensors. In this study, research and development were conducted for devices with a piezoelectric coefficient (d33) of 300[pC/N] or more for actuators. For this purpose, K+ exceeding 0.02 to 0.12 mol% was added to (Na0.78K0.22)0.5Bi0.5TiO3 to analyze structural changes due to K+ excess, and (Na0.78K0.22)0.5Bi0.5TiO3 + 8mol% K2CO3 Ti4+ was substituted with Fe3+ to manufacture lead-free piezoelectric materials. As a result, ceramics with Fe3+ substitution at x = 0.0075 yielded an average value of d33 = 315[pC/N]. Furthermore, for ceramics with Fe3+ substitution at x = 0.0075, the average values of maximum polarization (Pmax), residual polarization (Prem), and coercive field (Ec) were found to be 39.63 μC/cm2, 30.45 μC/cm2, and 2.50 kV/mm, respectively. The reliable characteristic values obtained from the research results can be applied to linear actuator components (such as the zoom function of mobile cameras, LDM for skin care, etc.) and ultrasonic vibration components.

최근 생활방식의 변화로 인하여 실내 생활이 점점 증가함에 따라 다양한 인테리어 자재의 수요가 증가하고 있으며, 이에 따라 인테리어 스톤 제품 생산 과정에서 발생하는 산업 폐기물인 슬러지의 발 생도 더불어 증가하고 있다. 발생하는 슬러지는 전량 소각 및 매립되어 처리되고 있으며 환경파괴 및 매립지 부족 등의 문제로 슬러지 처리에 어려움을 겪고 있는 실정이다. 이와 더불어 최근 건설 현장의 골재 수급은 매우 어려운 상황이며 이는 직접적으로 레미콘의 품질 및 가격에 영향을 미치게 된다. 이 러한 문제점의 해결을 위하여, 본 연구에서는 모르타르 내부의 잔골재를 인테리어 스톤 슬러지로 치환 하여 슬러지의 친환경적 재활용성을 검토하고자 하였다. 선행 연구를 바탕으로 시멘트, 슬러지, 잔골 재, 고유동화제 등을 활용하여 배합비를 설정하였으며, 이에 대한 시험체를 제작 하였다. 잔골재 무게 대비 슬러지는 각각 5, 10, 15, 20%를 치환하였으며, 각 배합에 대한 유동성과 재령별 압축강도를 측 정하였다. 관입저항 실험을 통해 각 시편의 초결과 종결 시간을 확인하였으며 수은압입법을 통해 시편 별 내부의 공극을 측정하였다.

This study was done to develop environmental risk assessments and a biosafety guide for insect-resistant genetically modified rice at a LMO (Living Modified Organism) isolation field. In the LMO quarantine area of Kyungpook National University, the species diversities and population densities of non-target insects found on insect-resistant genetically modified rice (Bt-T) resistant to Cnaphalocrocis medinalis and on non-GM rices (Dongjin-byeo and Ilmi-byeo) were investigated. The Bt-T event was therefore evaluated under field conditions to detect possible impacts on the above ground insects and spiders. The study compared transgenic rice and two non-GM reference rices, Dongjinbyeo and Ilmi-byeo, at Gunwi in Southern Korea in 2016 and 2017. A total of 9,552 individuals from 51 families and 11 orders were collected from the LMO isolation field. In the three types of rice fields, a total of 3,042 individuals from the Bt-T, 3,213 individuals from the Dongjin-byeo, and 3,297 individuals from the Ilmi-byeo were collected, respectively. There was no difference between the population densities of the non-target insect pests, natural enemies and other insects on the Bt-T and non-GM rices. The data of insect species population densities were subjected to principal component analysis (PCA), which not distinguished among the three varieties, GM and non-GM, reference cultivar in all cultivation years. However, PCA results were clearly separated the samples based on the cultivation years. These results suggest that insect species diversities and population densities during plants cultivation are determined by environmental factors (growing condition and seasons) rather than by genetic factors.

Insect-resistant transgenic (Bt-9) rice was generated by inserting the mCry1Ac1 a modified gene from the soil bacterium Bacillus thuringiensis into the genome of a conventional variety of rice (Ilmibyeo). With regard to the potential problems of safety, the non-target organism evaluation is required as an essential element for the environmental risk assessment of genetically modified (GM) crops. For biosafety assessment, we studied the effects on survival of cantor Daphnia magna, a commonly used as a model organism in ecotoxicological studies. D. magna fed on Bt-transgenic rice (Bt-9) and its near non-GM counterparts (Ilmibyeo) grown in the same environment (100% ground rice suspension). The Bt-9 rice was comfirmed to have the insertion of T-DNA and protein expression by the PCR and ELISA analysis. Feeding study showed similar cumulative immobility and abnormal response of Daphnia magna between Bt-9 rice and Ilmibyeo. 48hr-EC50 values of Bt-9 and Ilmi rice showed 4,400 mg/L (95% confidence limits: 3861.01 ~ 5015.01 mg/L) and 5,564mg/L (95% confidence limits: 4780.03 ~ 6476.93 mg/L) respectively. The rice NOEC (No observed effect concentration) value for D. magna was suggested 1,620mg/L. We conclude that the tested Bt-9 and Ilmi similar cumulative immobility for D. magna the widely used model organism. We found out that there is strong possibility that the growth of Bt-9 didn’t affect to non-target insects.

형질전환(Living Genetically Modified)벼와 비변형 벼 재배지역의 곤충상 변동 양상을 2016년 7월부터 2016년 10월까지 비교 조사중이다. 경상대 사천 LMO 격리포장과 경북대 군위 LMO 격리포장에서 Bt(Bacillus thuringiensis) 형질전환 벼를 재배하여 조사하였고, 사천시 두량리, 선진리, 군위군 화계리에서 비변형 벼 재배지를 선택하여 조사하였다. 현재까지 조사결과로 사천 LMO 격리포장에서는 총 10목 41과 86종 1,058개체, 군위 LMO 격리 포장은 총 11목 49과 103종 1,697개체, 두량1 포장은 총 9목 38과 80종 1,035개체, 두량2 포장은 총 11목 55과 101종 1,071개체, 선진 포장은 총 10목 43과 74종 428개체, 화계1 포장은 총 10목 44과 83종 2,663개체, 화계2 포장은 총 11목 51과 98종 1,556개체가 채집되었다. 현재 형질전환 벼와 재배 벼 사이의 차이가 나타나지 않았다. 10월까지 실험을 진행, 군집분석하여 비교할 예정이다.

Bacillus thuringiensis (Bt) produces a variety of insecticidal crystal proteins and widely used as one of the most successful biological control agents. Recently, studies that introduce cry genes into crops to create pest resistance have made much progress, and the total area of land planted with Bt crops has increased substantially. In this study, pest resistance of 8 transgenic Bt rice events with a synthetic cry1Ac gene linked to rice rbcS-tp sequence were assessed under laboratory conditions. Bioassays were performed against Cnaphalocrocis medinalis, which is a significant pest of rice in Asia. C. medinalis larvae were shown to be susceptible to all eight events, even though there were differences between the causes of death. The results differed between developmental stages of the larvae, despite the fact that all 8 events led to high mortalities. These results may be a significant foundation for the evaluation of improved transgenic Bt rice.

비티 포자와 Xenorhabdus nematophila (Xn)의 배양액을 혼합하여 비티플러스가 개발되었다. 높은 살충력에도 불구하고 비티플러스는 다 양한 해충에 대한 넓은 살충범위를 보이지 않는 한계가 있다. 본 연구에서는 Xn 대사물질 첨가를 통한 파밤나방과 같은 비감수성 해충에 대한 비 티플러스의 살충력 향상에 초점을 맞추었다. Xn의 주요 대사물질인 oxindole (OI)과 benzylideneacetone (BZA)는 비티의 살충력을 향상시킨 다고 보고되었다. 본 연구에서 OI 또는 BZA의 첨가는 비티플러스의 살충력을 향상시켰다. 그러나 동결건조된 Xn 배양액의 첨가는 보다 낮은 농 도의 OI 또는 BZA로도 충분히 비피플러스의 살충력을 상승시켰다. HPLC 분석에서 Xn 배양액에 최소 12개의 대사물질이 포함되어 있는 것을 확인하였다. 이러한 결과는 OI와 BZA 외에도 Xn 대사물질에 생리활성물질이 존재하는 것을 제시한다.

Cabbage is one of the major vegetable crops especially in Korea. Various insect pests intimidate the cabbage production. Moreover, an excessive spray of chemical insecticides leads to development of insecticide resistance as well adverse effects on environment and humans. The brassica leaf beetle, Phaedon brassicae, is a coleopteran pest. Both larval and adult stages feed cabbage. This study aimed to develop an effective microbial biopesticide against P. brassicae by adding immunosuppressive agent to Bacillus thurigiensis (Bt). To determine an optimal immunosuppressive agent, two bacterial species of Photorhabdus temperata subsp. temperata (Ptt) and Xenorhabdus nematophila were compared in their insecticidal activity against P. brassicae, and Ptt was selected. Among four subspecies of Bt, B. thuringiensis subsp. tenebrionis (Btt) was selected. Ptt bacterial culture broth possessed immunosuppressive agent(s) because the bacterial culture broth significantly increased other bacterial growth in P. brassicae hemolymph. When the Ptt broth was added to Btt, it significantly increased the insecticidal activity of Btt. Bt-Plus was prepared by mixing Btt and Ptt bacterial culture and sprayed the cabbage infested by P. brassicae. The Bt-Plus was much more effective than Btt treatment. This study reports a novel Bt insecticide to control P. brassicae.

Evolution of resistance to entomopathogenic bacterium, Bacillus thuringiensis (Bt), can potentially reduce the efficacy of insecticidal proteins from Bt to insect pests in fields. Bt resistance is involved in modification of the toxin binding to its specific midgut membrane receptors, such as cadherin, aminopeptidase N, alkaline phosphatase, and ABC transporters. The beet armyworm, Spodoptera exigua, is one of major lepidopteran insect pest in Korea and showed highly susceptible to Cry1Ca. We investigated the Cry1Ca toxicity with respect to its binding affinity to a Bt receptor, cadherin compared with Cry1Ac. RNA interference (RNAi) of a cadherin of S. exigua (SeCad1) significantly suppressed the Cry1Ca to the toxic level of Cry1Ac. Binding affinity of Cry1Ca to brush border membrane vesicle (BBMV) of S. exigua midgut was significantly lost after SeCad1 RNAi. Binding affinity of Cry1Ac to BBMV was much low compared to that of Cry1Ca and less sensitive to SeCad1 RNAi. Direct binding assay of Cry toxins to SeCad1 was assessed using a recombinant cadherin repeat 10-11 (rCR10-11) of SeCad1. The addition to rCR10-11 to Cry1Ca significantly enhanced the toxicity under SeCad1 RNAi. However, the synergistic effect of rCR10-11 on toxicity of Cry1Ac was not much significant with poor binding affinity of Cry1Ac compared to Cry1Ca. These results indicate that the differential toxicity of Cry toxins against S. exigua is caused by the different affinities to the Bt receptor, cadherin.

곤충병원성세균 Xenorhabdus nematophila (Xn)의 일부 대사물질은 대상 곤충의 phospholipase A2 (PLA2)를 억제하여 아이코사노이드 생합성 활성을 저해시킨다. 그러나 이들 세균 대사물질이 억제하는 곤충의 PLA2에 대해서는 알려져 있지 않다. Xn의 배양액에서 화학구조가 동정된 8 가지 대사물질들은 두 종의 나비목 배추좀나방(Plutella xylostella)과 파밤나방(Spodoptera exigua)의 유충에 대하여 살충 활성을 보유했다.특별히 이들 물질은 모두 Bacillus thuringiensis (비티)의 살충력을 크게 향상시켰다. 파밤나방의 세포성 인지질 분해효소(SecPLA2)를 클로닝하고 대장균에서 과발현시켰다. 분리된 SecPLA2를 지방체에서 얻은 인지질과 반응시켰을 때 여러 다가불포화지방산을 해리시켰다. 이 효소활성이 Xn 유래 대사물질들에 의해 뚜렷이 억제되었다. 또한 SecPLA2에 대한 억제효과와 비티 살충력 상승효과 사이에 정의 상관관계를 보였다. 본 연구는 SecPLA2가 Xn 대사물질의 억제 대상 분자 종말점 가운데 하나라고 제시하고 있다.

해충저항성 유전자변형 작물은 대상 해충에 대한 방제 효과를 증진시킬 수 있는 효과적인 수단이 될 수 있지만, 생태계 내의 다른 비표적 생물에 부정적인 영향을 줄 가능성 또한 있기 때문에 상업적인 재배에 앞서 이에 대한 충분한 연구가 이루어져야 한다. 본 연구에서는 배추좀나방 내성 유전자변형 Bt (Cry1Ac1)양배추가 비표적 곤충인 복숭아혹진딧물에 미치는 영향을 알아보기 위한 기초적인 실험으로서 기주선택실험 및 성장실험을 실시하였다. 기주선택실험에서, 두 개체씩의 Bt 양배추와 모본 양배추에 각각 10마리의 유시 성충(alate virginoparae)을 접종하고, 사흘간 생식(reproduction) 기회를 제공한 후 생산한 약충의 마리수를 측정한 결과, Bt 양배추와 모본 양배추에 낳은 약충의 수가 각각 21.9±1.8와 22.5±2.2로 비슷하였다. 성장실험에서, 갓 태어난 무시 약충(apterous virginoparae)을 Bt 양배추 및 모본 양배추를 기주로 하여 키웠을 때, 성충이 될 때까지 걸린 시간은 Bt 양배추와 모본 양배추에서 각각 5.8±0.2, 5.9±0.1 일(day)로 통계적으로 유의한 차이가 없었고, 개체군 생장률(rm) 또한 0.7±0.1, 0.8±0.1로 유사하였다. 이상의 결과들로 볼때 Bt 양배추가 복숭아혹진딧물에 미치는 영향이 없거나 미미함을 알 수 있으나, 다양한 관점에서의 보완 연구가 더 필요하다.

An entomopathogenic bacterium, Bacillus thuringiensis (Bt), is Gram-positive and undergoes sporulation along with the production of the insecticidal crystal toxins in a paraspore form. This study investigated the biochemical and insecticidal activities of Cry toxins of various Bt strains of Bt aizawai, Bt kurstaki, Bt tenebrionis, and Bt israelensis. Bt aizawai for a Cry1C (135 kDa), Bt kurstaki for a Cry1A (133 kDa), Bt tenebrionis for a Cry3 (73 kDa), Bt israelensis for a Cry4A (134 kDa) and Cry4B (128 kDa). To look for insect pest spectra of these four Cry toxins against four different insects, Cry1A was the most potent to Plutella xylostella, Cry1C to Spodoptera exigua, Cry3 to Tribolium castaneum, and Cry4A to Drosophila melanogaster. To further analyze the differential insecticidal activities of Cry toxins, two Cry toxin genes were expressed using baculovirus expression system. Both Cry1Ac and Cry1Ca toxins significantly enhanced the baculoviral pathogenicity against P. xylostella and S. exigua. However, the synergistic effects were different depending on the type of Cry toxins. These results suggest that the different insecticidal spectra of different Bts are explained by the different Cry toxins produced by the bacteria.

A phase variation has been reported in an entomopathogenic bacterium, Xenorhabdus nematophila. Compared to a wild type primary form, a secondary form usually lose several physiological and biochemical characters. This study showed that the phase variation of X. nematophila caused a significant alteration in its immunosuppressive activity and subsequent entomopathogenicity. A secondary form of X. nematophila was detected in laboratory colonies and exhibited significant differences in dye absorption and entomopathogenicity. In addition, the secondary form was different in production of eicosanoid-biosynthesis inhibitors (EBIs) compared to the primary form of X. nematophila. Production of oxindole and p-hydroxypropionic acid was significantly reduced in the culture broth of the secondary form of X. nematophila. The reduced EBI production resulted in significant suppression in the inhibitory effects on a cellular nodule formation and phenoloxidase activity. Culture broth of the primary form of X. nematophila significantly more enhanced the pathogenicity of Bacillus thuringiensis (Bt) than the culture broth of the secondary form. Furthermore, this study developed a high efficient ‘Dual Bt-Plus’ to control both lepidopteran insect pests of Plutella xylostella and Spodoptera exigua by mixing two effective Bt strains along with the addition of potent bacterial metabolites or 100-fold concentrated X. nematophila culture broth.

곤충병원세균(Bacillus thuringiensis: 비티)의 살충효과를 증가시킨 미생물살충제 “비티플러스”가 개발되었다. 그러나 수화제 형태의 비티플러스는 농가나 산업체에서 높은 단가로 선호하지 않고 있는 실정이다. 이에 본 연구는 액상 제형의 비티플러스를 개발하는 연구 목적을 두었다. 이러한 목적에 따라 먼저 비티플러스 제조에 포함되는 두 세균 배양액의 최적 혼합 비율을 결정하였다. 이 최적 혼합액은 10%의 에탄올을 보존제로 사용되었으며, 비티와 또 다른 곤충병원세균인 Xenorhabdus nematophila (Xn)의 배양액 비율이 5:4 (v/v)로 제조하게 했다. 또한 이 액상제형이 1,000 희석배수에서 효과를 보이기 위해 비티 배양액을 10 배 농축하여 최적 비율로 혼합하였다. 이렇게 해서 얻어진 액상 제형을 발육 후기 유충의 배추좀나방(Plutella xylostella)이 가해를 하는 배추밭에 처리하여 7일 후 약 77%의 방제 효과를 보였는데, 이 처리 효과는 현재 상용화되는 배추좀나방 적용 생물농약들과 비등한 효과를 나타내는 것으로 판명되었다. 저온 및 상온의 저장 분석에서 본 액상 제형은 최소한 한 달 동안 안정된 방제효과를 나타내는 것으로 분석되었다. 이 액상 제형의 안정된 방제 효과를 보장하여 주는 품질관리 기술을 개발하기 위해 제형 내비티 포자 밀도와 Xn 유래 유용물질의 농도를 판별하였다. 본 연구 분석은 최적의 방제 효과를 나타내기 위해서는 비티플러스 액상 제형에 비티 포자 밀도가 최소 5 × 1011 spores/mL 이고, Xn 세균 대사물질들 가운데 8 종 유효물질의 농도가 품질관리 판별 기준으로 제시되었다.

Parasitism by an endoparasitoid wasp, Cotesia plutellae, results in significant immunosuppression of the diamondback moth, Plutella xylostella. Parasitized larvae significantly suffered higher susceptibility to a microbial biopesticide, Bacillus thuringiensis (Bt) than nonparasitized (NP) larvae. To find out an immunosuppressive agent causing the enhanced Bt efficacy, viral ankyrin (=vankyrin) genes encoded in C. plutellae bracovirus (CpBV) were analyzed by transient expression in NP larvae. CpBV segments containing different vankyrins were microinjected to NP larvae and expressed their encoded vankyrins. Expression of some vankyrins significantly inhibited immune response and enhanced Bt efficacy. This study suggests that expression of vankyrins suppress a cellular immune response and lose Bt tolerance of P. xylostella larvae.

To assess effects of Bt rice expressing a synthetic Cry1Ac1 gene for control Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae), we conducted laboratory tests to evaluate the potential impacts of Bt rice on non-target herbivore, non-target pollen-feeder and non-target predator. Also we investigated the community structure of arthropods in Bt and non-Bt rice fields during the rice-growing season in 2007 and 2008. There were no significant differences in development, survival and emergence of non-target herbivores, non-target pollen-feeder and non-target predators between Bt and non-Bt rice although tibia length of non-target predators with BPH feeding on Bt rice showed significantly longer than in non-Bt rice. In 2-year field study, a total of 43 familes in 10 orders were identified from 64,099 collected insects and a total of 29 species in 23 genera and 9 families were identified from 4,937 collected spiders. Abundance, Shannon’s index and family richness in insects and species richness in spiders were very similar between Bt and non-Bt rice for 2 years and there was no significant difference. The results indicated that the transgenic Cry1Ac rice tested in this study had no adverse effects on the rice insect and spider community structure in field condition and on the development, survival, emergence and adult fitness parameter of non-target arthropods in the laboratory conditions.