• The Plant Pathology Journal
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• 제21권3호
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• pp.288-292
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• 2005

Pathogenesis-related protein-1a (PR-1a) is strongly induced in tobacco plants by pathogen attack, exogenous salicylic acid (SA) application and by other developmental processes. In order to develop a rapid screening system for the selection of plant defense-inducing compounds originated from various sources, we have transformed tobacco Samsun NN plants with a chimeric construct consisting of GUS $(\beta-glucuronidase)$. In the $T_1$ generation, three transgenic lines having stable GUS expression were selected for further promoter analysis. Using GUS histochemical assay, we observed strong GUS induction driven by PR-1a promoter in PR1a-GUS transgenic tobacco leaves in response to the exogenous application of SA or benzol (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (BTH), a SA­derivative compound. In addition, GUS expression was maintained locally or systemically in PR1a-GUS transgenic line $\#5\;T_2$ generation) until after 3 days when they were treated with same chemicals. Our results suggested that the PR1a-GUS reporter gene system in tobacco plants may be applicable for the large-scale screening of defense-inducing substances.

• 한국가축번식학회지
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• 제22권2호
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• pp.127-136
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• 1998

A chimeric gene comprising murine whey acidic protein(mWAP) and human growth hormone(hGH) was used to produce transgenic rats express hGH and secrete it into the blood. Two lines of transgenic rats carrying the mWAP/hGH construct were established; High line was characterized by relatively high levels of serum hGH, and low line had relatively low levels. The secretory profiles of rat GH(rGH) as well as hGH, the transgene product, were obtained in transgenic males and females of low line; both hGH and rGH serum levels were flattened with no episodic fluctuations, and the overall mean concentration of rGH was significantly lower than in normal littermates. Although the animals of High line showed an acceles, as assessed by vaginal opening and occurrence of first ovulation, advanced by 7∼8 days in both lines of animals. Accordingly, the body weight at puberty of low line transgenic females was much lower than that of normal littermates, indicating that continuous hGH expression could induce precocious puberty without enhancing the growth rate.

• 한국자원식물학회지
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• 제10권4호
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• pp.300-304
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• 1997

저온관련 유전자인 H28 유전자를 갖고 있는 Agrobacterium MP90균주를 Desiree와 Atlantie 감자 품종의 잎절편과 공동배양한 후 약 6-8주 후에 항생제가 첨가된 선발배지에서 multiple shoots를 얻을수 있었다. 선발된 형질전환체를 대상으로 PCR 방법을 이용한 NPT II 유전자와 H28를 확인한 결과 내한성유전자가 식물체의 genome에 안정적으로 삽입되었음을 확인하였고 northern blot 확인에 의하여 내한성 유전자가 발현됨을 확인하였다.

• The Plant Pathology Journal
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• 제20권3호
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• pp.212-219
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• 2004

Three isolates of Cucumber mosaic virus (CMV) from lily plants showing mosaic and distortion symptoms were detected by reverse-transcriptase polymerase chain reaction (RT-PCR) using primers specific to Cucumovirus genus namely, LK-CMV, LK4-CMV, and LKS-CMV. Restriction enzymes patterns of the RT-PCR products revealed that the lily isolates belonged to subgroup IA of CMV. In terms of biological properties, the lily isolates have highly similar but distinct pathogenicity as reported in other lily strains and ordinary strains of CMV. To characterize the molecular properties, cDNAs containing coat protein (CP) gene and 3' non-coding region (NCR) of RNA3 for the isolates were cloned and their nucleotide sequences were determined. The CP similarity (218 amino acids) was highly homologous (>97％) with that of subgroup I CMV strains. However, an additional 20-nulcleotide long segment was only present in 3' NCR of lily isolates, which form an additional stem-loop RNA structure. By using chimeric construct exchange cDNA containing 3'NCR of LK-CMV into the full-length cDNA clone of RNA3 of Fny-CMV, this additional segment may prove to be significant in the identification and fitness of the virus in lily plants. The pathology of zucchini squash infected by F1F2L3-CMV, a pseudorecombinant virus was showed to change drastically the severe mosaic and stunting symptom into a mild chlorotic spot on systemic leave, compared with Fny-CMV. To delimit the sequence of RNA3 affected the pathology, various RNA3 chimeras were constructed between two strains of CMV. The symptom determinants of F1F2L3-CMV were mapped to the positions amino acid 234, 239, and 250 in 3a movement protein (MP). RNA3 chimeras changed the sequences encoding three amino acids were resulted in alteration of systemic symptom.

• 한국미생물·생명공학회지
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• 제29권1호
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• pp.1-11
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• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.2079-2094
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• 2018

Sunflower trypsin inhibitor (SFTI) is a 14-amino-acid bicyclic peptide that contains a single internal disulfide bond. We initially constructed chimeras of SFTI with N-terminal secretion signals from the Escherichia coli OmpA and Pseudomonas aeruginosa ToxA, but only detected small amounts of protease inhibition resulting from these constructs. A substantially higher degree of protease inhibition was detected from a C-terminal SFTI fusion with E. coli YebF, which radiated more than a centimeter from an individual colony of E. coli using a culture-based inhibitor assay. Inhibitory activity was further improved in YebF-SFTI fusions by the addition of a trypsin cleavage signal immediately upstream of SFTI, and resulted in production of a 14-amino-acid, disulfide-bonded SFTI free in the culture supernatant. To assess the potential of the secreted SFTI to protect the ability of a cytotoxic protein to kill tumor cells, we utilized a tumor-selective form of the Pseudomonas ToxA (OTG-PE38K) alone and expressed as a polycistronic construct with YebF-SFTI in the tumor-targeted Salmonella VNP20009. When we assessed the ability of toxin-containing culture supernatants to kill MDA-MB-468 breast cancer cells, the untreated OTG-PE38K was able to eliminate all detectable tumor cells, while pretreatment with trypsin resulted in the complete loss of anticancer cytotoxicity. However, when OTG-PE38K was co-expressed with YebF-SFTI, cytotoxicity was completely retained in the presence of trypsin. These data demonstrate SFTI chimeras are secreted in a functional form and that co-expression of protease inhibitors with therapeutic proteins by tumor-targeted bacteria has the potential to enhance the activity of therapeutic proteins by suppressing their degradation within a proteolytic environment.

• 한국동물학회지
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• 제28권3호
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• pp.166-178
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• 1985

한국형 B형 간염바이러스(HBV) DNA의 표면항원 유전자를 포유동물 세포에서 발현시켜 항원의 검출과 유전자의 분자유전학적인 연구를 하기 위하여 pre-surface antigen 지역과 표면항원 유전자 그리고 poly(A) addition site가 포함된 DNA 조각을 simian virus 40(SV 40)의 DNA 복제 원점과 promoter가 포함된 유전자 운반체에 재조함 시켰다. 우선, HBV DNA가 들어있는 pHBV 107을 Bam HI으로 부분절단한뒤 self-ligation시켜 두 HBV DNA가 같은 방향으로 들어간 pHBVD 107을 만들었다. 이 plasmid를 Bgl II로 절단하였을때 pre-surface지역과 표면항원 유전자 그리고 poly(A) addition site가 함께 포함된 2.7 kb의 insert DNA 조각을 얻었다. 유전자 운반체로는 포유동물세포에서 복제할 수 있도록 하기 위하여 SV40의 DNA 복제 원점부위와 72 bp repeats(enhancer)가 포함된 pSVOE를 만든다음 이 vector의 Pvu II 절단자리에 Bam HI linker를 붙여 insert DNA가 vector의 SV40 late promoter지역 가까이에 들어갈 수 있도록 변형시킨 pSVOB를 만들었다. 이상과 같이 만들어진 pre-surface 지역-표면항원유전자-poly(A)-addition site가 포함된 2.7 kb DNA 절편을 pSVOB promoter 뒤의 Bam HI site에 삽입하여 재조합된 plasmid pSVBS를 얻었다. 예비실험으로 pSVBS를 T-antigen이 생산되는 COS cell에 이주시켰더니 $HB_sAg$가 발현됨을 보았다.