• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.181-185
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• 1995

To enhance expression of foreign gene by the novel expression vector, pBmKSK1, of Bombyx mori nuclear polyhedrosis virus, E. coli $\beta$-galactosidase gene expressing recombinant virus was infected in BmN-4 cells and various concentrations of silkworm hemolymph were added to the recombinant virus-infected BmN-4 cells containing fetal bovine serum. The expression efficiency of foreign gene was determined by $\beta$-galactosidase activity in the culture media. The results showed that the silkworm hemolymph was effective to expression of foreign gene in the BmN-4 cells, suggesting that the silkworm hemolymph could be substituted for fetal bovine serum in the BmN-4 cells to enhance expression of foreign gene.

• ETRI Journal
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• v.32 no.5
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• pp.784-794
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• 2010

Automatic facial expression recognition has many potential applications in different areas of human computer interaction. However, they are not yet fully realized due to the lack of an effective facial feature descriptor. In this paper, we present a new appearance-based feature descriptor, the local directional pattern (LDP), to represent facial geometry and analyze its performance in expression recognition. An LDP feature is obtained by computing the edge response values in 8 directions at each pixel and encoding them into an 8 bit binary number using the relative strength of these edge responses. The LDP descriptor, a distribution of LDP codes within an image or image patch, is used to describe each expression image. The effectiveness of dimensionality reduction techniques, such as principal component analysis and AdaBoost, is also analyzed in terms of computational cost saving and classification accuracy. Two well-known machine learning methods, template matching and support vector machine, are used for classification using the Cohn-Kanade and Japanese female facial expression databases. Better classification accuracy shows the superiority of LDP descriptor against other appearance-based feature descriptors.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.228-233
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• 2008

Effects of chaperones on mRNA stability and gene expression were studied in order to develop an efficient Escherichia coli expression system that can maximize gene expression. The stability of mRNA was modulated by introducing various secondary structures at the 5'-end of mRNA. Four vector systems providing different 5'-end structures were constructed, and genes encoding GFPuv and endoxylanase were cloned into the four vector systems. Primer extension assay revealed different mRNA half-lives depending on the 5'-end secondary structures of mRNA. In addition to the stem-loop structure at the 5'-end of mRNA, coexpression of dnaK-dnaJ-grpE or groEL-groES, representative heat-shock genes in E. coli, increased the mRNA stability and the level of gene expression further, even though the degree of stabilization was varied. Our work suggests that some of the heat-shock proteins can function as mRNA stabilizers as well s protein chaperones.

• BMB Reports
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• v.30 no.4
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• pp.269-273
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• 1997

Heptocvte-specific expression induced by Hepatitis B virus (HBV) enhancer 2-core gene promoter was examined in various hepatocyte and non-hepatocyte cell lines. using non-viral and retroviral vector systems in which chloramphenicol acetyltransferase (CAT) is used as a reporter. The non-viral plasmid containing the HBV enhancer 2-core promoter exhibited 22 and 66% of CAT activities in hepatoma cell lines. HepG2 and Hep3B, respectively when compared with CAT activity expressed by CMV promoter. The CAT activities, however. were found to be marginal in other tested hepatoma cell lines as well as mouse primary hepatocytes and non-hepatocytes. The HBV enhancer 2 located upstream the CMV promoter did not affect the CMV promoter activity nor provided hepatocyte-specific expression. Transfection of retroviral plasmid DNA containing the HBV enhancer 2-core promoter as an internal promoter exhibited high and specific CAT expression in HepG2 and Hep3B cell lines but the activity value was 5 to 10 fold lower than the non-viral plasmid with identical promoter. These results suggest that the usage of HBV enhancer 2-core promoter for liver specific expression is limited to certain vectors and hepatocyte cell lines.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.994-996
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• 2012

We constructed novel recombinant baculovirus vector system. This vector system contained coding genes for polyhedron promoter, vesicular stomatitis virus G (VSVG), polyA, cytomegalovirus (CMV) promoter, enhanced green fluorescent protein (EGFP), and protein transduction domain (PTD). We compared efficacy and rate of expression of this novel recombinant baculovirus vector system with other control vector system. From this result, we confirmed that this novel recombinant baculovirus vector system was superior to other control vector system.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.545-554
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• 2013

Plasmid isolation of kimchi-derived Weissella cibaria KLC140 revealed six different plasmids. The smallest plasmid, pKW2124, was DNA sequenced and characterized, showing 2,126 bp with a GC content of 36.39% and five putative open reading frames (ORFs). In silico analysis of these ORFs showed ORF1 encodes a putative replication protein similar to rolling circular replication proteins from other lactic acid bacteria. However, a single-stranded intermediate was not detected when S1 nuclease was treated, suggesting it may follow theta replication. Interestingly, the replication initiation site of this plasmid is 100% identical to other plasmids from lactic acid bacteria, suggesting it may function for replication initiation. To construct a surface layer expression vector, pTSLGFP, slpA encoding the surface layer protein from Lactobacillus acidophilus was PCR amplified and fused with the gfp gene, forming a SLGFP fused gene. The plasmid pKW2124 was cloned into the XbaI site of pUC19, forming an Weissella-E. coli shuttle vector pKUW22. NheI-linearized pTSLGFP was ligated into pKUWCAT containing pKUW22 and the chloramphenicol acetyltransferase gene from pEK104, resulting in an 8.6 kb pKWCSLGFP surface layer expression vector. After transformation of this vector into W. cibaria KLC140, a GFP fluorescence signal was detected on the surface of the transformant, substantiating production of SLGFP fused protein and its secretion. This is the first report for construction of a Weissella surface layer expression vector, which may be useful for surface layer production of beneficial proteins in Weissella.

• Korean Journal of Animal Reproduction
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• v.19 no.1
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• pp.35-41
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• 1995

In this study, we have tested whether the retrovirus vector system is applicable in transgenic cattle production. To overcome low infectivity of currently available retrovirus vector system we have directly microinjected retrovirus-producing cells into the perivitelline space of the day 1.5 embryos. The virus-producing cell line was designed to release replication-defective retrovirus encapsidated with Gibbon ape leukemia virus (GaLV) envelope protein. E. coli LacZ gene was used as a marker gene to facilitate evaluation of the transgene expression and X-gal staining at morula or blastocyst stage resulted in expression of E. coli LacZ gene The results in these experiments were summarized as follows : 1. The lowest concentration of polybrene necessary for efficient virus infection was Sf' g/ml. 2. Development rate from day 1.5 embryos microinjected with virus-producing cells to the morulae /blastocysts was 29%. 3. 21% of the morulae /blastocysts were LacZ+. 4. There was no evidence that the retrovirus-producing cells used in this study produced replication-competent retrovirus.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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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.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.202-205
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• 2000

A gene coding $endo-{\beta}$,-1, 4 glucanase from Actinomyces sp. KNG40 and phytase from Hansenula polymorpha were cloned into Esherichia coli JM101 by using E. coli/Lactobacillus shuttle vector pNZ3004 and pNZ123. The plasmid p3PS(1-4) and p123(1-4) have slpA promoter and slpA signal sequence. So, I constructed expression vectors, p3PS(1-4)Endo, phy and p123(1-4)Endo, phy. These constructed vector was transformed in target host Lactobacillus gasseri and reutri. These transformed host expressed endoglucanase and phytase as extracellular fraction. In the enzyme activity of the same vector, host L, gasseri was higher activity than L. reuteri. This indicates that L. gasseri recongnize promoter and signal sequence very well.

• BMB Reports
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• v.40 no.5
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• pp.656-661
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• 2007

In this report, we describe an optimized method for generation of ephA8 BAC transgenic mice expressing the lacZ reporter gene under ephA8 regulatory sequences. First, we constructed a targeting vector that carries a 1.2 kb ephA8 DNA upstream of its first exon, a lacZ expression cassette, a kanamycin cassette, and a 0.7 kb ephA8 DNA downstream of its first exon. Second, the targeting vector was electroporated into cells containing the ephA8 BAC and pKOBEGA, in which recombinases induce a homologous recombination between the ephA8 BAC DNA and the targeting vector. Third, the FLP plasmid expressing the Flipase was electroporated into these bacteria to eliminate a kanamycin cassette from the recombinant BAC DNA. The appropriate structures of the modified ephA8 BAC DNA were confirmed by Southern analysis. Finally, BAC transgenic mouse embryos were generated by pronuclear injection of the recombinant BAC DNA. Whole mount X-gal staining revealed that the lacZ reporter expression is restricted to the anterior region of the developing midbrain in each transgenic embryo. These results indicate that the ephA8 BAC DNA contains most, if not all, regulatory sequences to direct temporal and spatial expression of the lacZ gene in vivo.