An efficient transient expression system has been developed and characterized for the production of foreign genes in seedlings. The seedlings can be easily produced from commercial seeds used for vegetable sprouts. In principal, a chemical abrasive was employed to generate wounds in seedlings prior to vacuum-infiltration with Agrobacterium tumefaciens bearing the target gene. This optimized chemical wounding-assisted agro-infiltration process resulted in up to 15-fold increase in β -glucuronidase (GUS) enzyme activity. This procedure has been used efficiently to express hepatitis B surface antigen (HBsAg) protein in a transient mode. Therefore, seedlings with proper wounds can be suggested as a convenient tool for the production of useful recombinant proteins.

Ceriporiopsis subvermispora is a unique white rot fungus degrading plant cell wall lignin without severe loss of cellulose. Recombinant plasmids containing homologous gene expression signals fused to the coding sequence of Escherichia coli hph which encodes for hygromycin phosphotransferase were introduced in protoplasts of wild type C. subvermispora using PEG/CaCl2 protocol. A number of hygromycin B resistant strains were isolated on a screening plate containing 100㎍/ml of hygromycin B: whereas, no colonies were observed when protoplasts were treated with no DNA as a negative control. It was demonstrated that most of the isolates lost their drug resistance during successive cultivations in the presence of the same concentration of hygromycin B, but some of the isolates showed stable drug resistance after five times repeated screening. They did not lose the drug resistance even after the cultivation in the absence of hygromycin B and incorporation of the hph sequence was confirmed by specific amplification of the target sequence in PCR experiments and Southern hybridization analysis. The stable transformation system will make it possible to do molecular genetic analysis, as well as breeding of genetically modified strains, in C. subvermispora. Moreover, it was demonstrated that recombinant constructs with truncated promoter showed reduced number of the drug resistant isolates on the first screening plate, in response with the length of the remaining promoter sequence. These findings indicated that unstable drug resistance observed in these isolates should originate from transient expression of the introducing marker genes, and that a promoter assay system has been developed for the first time in basidiomycete. This system is practically not affected by the positional effect of the integrated recombinant gene in the host chromosome.

The Heavy Water Reactor(HWR) Heat Transport(HT) system transient analysis for the design of major nuclear equipment during normal and abnormal operating conditions was performed. The compliance with requirements of AECB Regulatory Document R-77 for CANDU reactor was estimated in CANDU-9 nuclear reactor. The analysis results showed that for each postulated accident the peak pressure values in the reactor headers are within the acceptance criteria given in ASME code requirements and the fuel overheating is prevented. The analysis results showed that the flow reversal through the fuel channel occurred but didn't result in any damage on the fuel bundle.

A polydnavirus, Cotesia plutellae bracovirus (CpBV), possesses segmented genome located on chromosome(s) of an endoparasitoid wasp, C. plutellae. An episomal viral segment (CpBV-S3) consists of 11,017 bp encoding two putative open reading frames (ORFs). ORF301 shows amino acid sequence homologies (28~50%) with RNase T2s of various organisms. It also contains BEN domain in C-terminal region. ORF302 is a hypothetical gene, which is also found in other bracoviruses. Both genes were expressed in larvae of Plutella xylostella parasitized by C. plutellae. ORF301 and ORF302 were transiently expressed in hemocyte, fat body, gut, and epidermis of P. xylostella. To analyze effects of these genes on the parasitism, the segment of CpBV-S3 was injected to non parasitized larvae of P. xylostella, in which the two genes were expressed at least for four days post-injection. The P. xylostella larvae injected with CpBV-S3 exhibited significant immunosuppression, such as reduction in total hemocyte population, suppression of immune associated genes including cecropin, pro-phenoloxidase (PO) and serpin1, and impairment in nodule formation behavior of hemocytes in response to bacterial challenge. Each gene expression in the treated larvae was inhibited by co-injecting respective double strand RNA (dsRNA) specific to each ORF. Injection of dsRNA of ORF301 could rescue the immunosuppression by the viral segmenttreated larvae, but not by ORF302 specific dsRNA. The larval injected with CpBV-S3 exhibited an enhanced susceptibility to baculovirus infection. These results indicate that ORF301 of CpBV-S3, which containing BEN domain, suppresses both cellular and humoral immune responses in P. xylostella.

Ischemia that causes stroke induces inflammation of brain cells and apoptosis and as a result, it influences much on the functional part of a man. The needle electrode electrical stimulation (NEES) that combines acupuncture of oriental medicine with electric therapy of western medicine relieves inflammation of cells and has effect on regrowth of nerve tissues. This study was conducted to verify the influence of NEES on the occurrence of c-Fos of cerebrum after applying NEES to the meridian point, Zusanli (ST 36) of a rats with induced ischemia. Global ischemia was induced by using ligation method on common carotid artery of male Sprague Dawley (SD) rats. The ligation was maintained for 5 minutes and then suture was removed for blood reperfusion. After inducing global ischemia, NEES was done to the left and right meridian points of Joksamri of a rat for 30 minutes after 12 hours, 24 hours, and 48 hours. The findings were as follows. 1. In the result of immunohistochemical method, the number of c-Fos immune response cells significantly decreased (P<.05) in NEES group than the control group (GI) that did not get NEES. 2. In the result of western blotting, the occurrence of c-Fos after 24 hours from the inducement of ischemia significantly decreased (P<.05) in NEES group than the control group (GI) that did not get NEES. Therefore, as the effect of NEES was shown highest after 24 hours from the ischemia, it is suspected that NEES would take important role in early treatment after cerebral stroke.

Perennial ryegrass (Lolium perenne L.) is one of the most important grass species in the world's temperate zones. It is used as high-quality forage in pastures and for recreational use as turf in golf courses, lawns and parks. Genetic improvement of perennial ryegrass is difficult due to its self-incompatibility. Consequently, progress by conventional breeding can be slow. Genetic transformation is an alternative that permits direct introduction of useful genes into a plant's genome and is becoming a powerful tool to complement conventional breeding. To improve environmental stress tolerance and quality of perennial ryegrass by introducing better and useful genes into the genome, we have developed a rapid and efficient transformation system using Agrobacterium-mediated gene transfer system.

외래단백질의 생산을 위하여 백합화분을 이용한 일시발현체계를 개발하였다. 충분히 성숙단계에 도달한 백합의 수술로부터 백합화분을 수집한 후 이들은 40-100 μm 크기의 aluminum oxide 입자와 함께 강하게 교반시켰다. 결과적으로 표면에 상해를 지닌 화분립에 대하여 erythropoietin(EPO) 유전자 DNA를 포함한 식물발현벡터(pBI-EPO)를 지니는 Agrobacterium tumefaciens LBA4404 세포들을 섞어 진공침윤을 수행하였다. Southern blot 및 cDNA blot hybridization의 분석 결과 EPO DNA의 화분 genomic DNA 삽입과 EPO mRNA의 생성이 각각 성공적으로 확인되었으며 이러한 결과는 Agrobacterium을 이용한 형질전환화분이 신속하고 편리한 단백질공장으로서 이용될 수 있음을 시사하고 있다.

본 논문은 로터 시스템의 디스크 회전운동을 표현하는데 있어 운동방정식을 통합하는 과정에서 기존 연구자들이 채택한 오일러 각 사용법이 일관성이 없음을 지적하였다. 기존 연구자들은 오일러 각 순서가 달라서 속도와 운동에너지도 달리 산정하였음은 물론, 운동방정식은 오직 선형 시스템만 취급해 왔다 이러한 오일러 각 사용법의 단점을 극복하기 위하여 회전운동을 더욱 단순하게 매개화할 수 있는 4원법(quaternion)과 구 좌표계를 적용하여 비선형 시스템을 도출하였다. 이를 바탕으로 수치해석을 통하여 기존 방법과 비교하여 제안한 방법의 신뢰성과 우수성을 보였다.

본 연구는 2차원 및 3차원 동적 탄소성 응력 해석을 위한 특수 적분해 경계요소법의 공식 개발을 제시한다 정적 탄성에 대한 기본식이 일반해를 구하는데 이용되었으며, 전체형상함수 개념을 이용하여, 변위율과 traction rate의 특수 적분해를 구함으로써 지배 방정식의 가속도 부분을 근사화시켰다. 시간 적분을 위하여 Houbolt 시적분 방법을 이용하였으며, Newton-Raphson 알고리즘을 이용하여 수치 연산을 행하였다. 제시된 공식에 따른 예제 해석을 통하여 그 방법의 유효성과 정확성을 설명하였다.

The diamondback moth, Plutella xylostella parasitized by its endoparasitoid Cotesia plutellae undergoes various physiological alterations which involves immunosuppression and developmental arrest. Its symbiotic virus, C. plutellae bracovirus (CpBV) is highly essential for their successful parasitization which possesses more than 136 genes encoded. CpBV15βunique in CpBV genome is expressed at low levels in early and at higher levels during late parasitization period. This gene product alters the hemocyte-spreading behavior through inhibition of protein synthesis under in vitro conditions. In the current study, we investigated its specific involvement in physiological functions in the host by transient expression and RNA interference techniques. The open reading frame of CpBV15βwas cloned into a eukaryotic expression vector and this recombinant CpBV15β was transfected into healthy non-parasitized 3rd instar P. xylostella by microinjection. CpBV15βwas expressed as early as 24 h and was consistent up to 72 h. Due to the expression of this gene, the hemolymph storage protein levels were significantly reduced and the ability of the hemocytes to adhere and spread on extracellular matrix was altered or reduced, wherein CpBV15βwas detectable in the cytoplasm of hemocytes based on indirect immunofluorescence assay. To confirm the role of CpBV15β, its double stranded RNA could efficiently recover the functional efficacy of hemocytes towards non-self and synthesis of storage proteins. Thus these results clearly demonstrate the role of CpBV15βin altering the host physiology by involving in cellular immune response and host protein synthesis.

원형축이 축방향으로 충격하중을 받으면 외경에서 반사된 파가 축의 중앙으로 집중되어 순간적으로 큰 응력이 발생하게 된다. 본 연구에서는 여러 가지 충격 축하중을 받는 횡등방성 반-무한 원형축을 대상으로 중실축 내의 종방향 응력전파를 축대칭 유한요소법과 Houtolt 시간적분법을 이용하여 프로그램을 작성하고 수치적으로 해석하여 그 결과를 횡등방성 재료의 재료구성비에 따라 자세히 설명한다. 제시된 해법의 타당성은 본 논문 수치 결과와 기 해석된 다른 해법에 의한 수치결과의 비교를 통해 검증된다. 여러 종류의 충격하중들에 따른 파동의 결과를 2차원, 3차원적으로 제시하여 축응력 전파를 이해하는데 기본 자료가 되도록 하였다. 또한 유한요소법을 이용하여 수치해석을 함에 있어 정확한 수치결과를 얻기 위한 무차원 동특성 시간변수에 대해 기술하였다.

본 논문에서는 극한 해상상태나 돌발적인 환경하중에서 양광시스템의 진수와 인양이 이루어질 때 발생할 수 있는 파이프의 점핑현상과 이에 의해 유발되는 파이프의 장력변화 및 위해도를 위한 해석기법을 제시하였다. 동적 과도응답 해석은 본 논문에서 제시된 기법에 의하여 여러 가지 형식의 임펄스에 대해 수행되어졌으며, 해석을 위한 모델로 KT-Submarine에서 사용하고 있는 '세계로호' 양광시스템의 진수, 인양 시스템을 선정하였다. 결과적으로 양광시스템관련 해상작업을 위한 지침이 제시되었다. 정성적인 해석기법의 검증과 비교를 위하여 ROV진수 시 발생 가능한 케이블장력 과도응답을 해석하였으며 이를 통하여, 본 연구에서 시도한 수학적 모델링과 이상화된 임펄스에 대한 파이프의 과도 응답과정이 충분한 정성적인 기초자료를 제공해 줄 수 있다는 점을 파악하였다.