• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.45-51
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• 1991

Inserting the $cI_{857}$ structural gene in the downstream of the tac promoter for the overproduction of $cI_{857}$ repressor protein was studied. DNA fragment containing $cI_{857}$ ; repressor gene was amplified by using plasmid pUC12, and partially digested with HphI. Only the $cI_{857}$ structural gene isolated was inserted in the downstream of the tac promoter. Plasmid pDR540- $cI_{857}$ having the tuc promoter-$cI_{857}$ structural gene insert could be isolated by the immunity of cells resistant at $30^{\circ}C$ and cell lysis at $42^{\circ}C$ to $\lambda$ phage $cI_{90}$. The amount of $cI_{857}$ repressor as 17% of total cellular protein were produced by using general E. coli as well as $lacI^q$ JM103 having this plasmid.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.122-128
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• 1992

Runaway replication plasmid pSY35AT was used for the production of $cI_{857}$ repressor protein. E, coli MC1065 having plasmid pSY35AT was shifted from $30^{\circ}C$ to $37^{\circ}C$ $cI_{857}$ repressor protein produced was purified by a modification of the purification method of wild type cI repressor. The concentration of purified $cI_{857}$ repressor protein was 0.11 mg/ml. The binding assay of $cI_{857}$ repressor and right promoter - right operater ($P_RO_R$) labeled with $^3H-CTP$ was done. Relative activity of purified cIx5, repressor was higher about 23 times than that of cell free extract. A higher value of the temperature in the binding assay led to a lower value of the binding activity.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.433-438
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• 1991

The plasmid pSY130-14 for the high production of phenylalanine is a temperaturecontrollable expression vector composed of the $P_R$ and the $P_L$ promoter and a temperature sensitive repressor, $cI_{857}$ of bacteriophage lambda. Strain AT2471 harbouring plasmid pSY13O- 14 is induced the phenylalanine production by shifting up the incubation temperaure to $38.5^{\circ}C$. Plasmid stability of E. coli AT2471 harbouring pSY130-14 was very low, it was about 30% after 48 h cultivation at $38.5^{\circ}C$ without kanamycin. The plasmid disappeared immediately at $40^{\circ}C$ without kanamycin, and at $40^{\circ}C$ adding kanamycin, the plasmid stability decreased at the beginning, but rose with the extension of the culture time. For the improvement of plasmid stability, the plasmid obtaind was designated as pSY15O-1 by changing origin region (ori) pACYC 177 of pSY130-14 for ori pSC101. E. coli AT2471 harbouring pSY150-1 was stable at $38.5^{\circ}C$ without tetracycline, and the plasrnid stability was about 40% after 48 h cultivation at $40^{\circ}C$.

• Applied Biological Chemistry
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• v.31 no.3
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• pp.219-225
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• 1988

Reverse transcriptase gene of Avian sarcoma virus(ASV) was cloned with a thermoinducible expression vector, pPL-lambda. E. coli N4830 which carries temperature sensitive cI857 la mbda repressor, was transformed with this pPL-pol plasmid DNA. The RNA transcribed by those tranoformants was isolated and analyzed. It was shown that the inserted reverse transcriptase gene of ASV was transcribed at high-level when cells were grown at high temperature.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1346-1352
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• 2005

We have developed a modified gene replacement method using PCR products containing short homologous sequences of 40- to 50-nt. The method required $\lambda$-Red recombination functions provided under the control of a temperature-sensitive CI857 repressor expressed from the $P_{lac}$ promoter in the presence of IPTG on an easily curable helper plasmid. The method promoted the targeted gene replacements in the Escherichia coli chromosome after shifting cultures of the recombinogenic host, which carries the helper plasmid, to $42^{\circ}C$ for 15 min. Since this method employs $\lambda$-Red recombination functions expressed from the easily curable helper plasmid, multiple rounds of gene replacements in the E. coli chromosome would be possible. The procedures described herein are expected to be widely used for metabolic engineering of E. coli and other bacteria.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.857-864
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• 2002

Channel coding is one of the most important things to improve digital communications. In this paper, we analyze the performance of turbo code with block interleaver using hopping algorithm (i. e., non-linear interleaver) for high speed multi-media service. The input and output of conventional block interleaver is achieved by the order of column and row, but hoping algorithm is achieved by hopping the column and row that increase the minimum distance and average distance between the nearest data dually. To verify and compare the performance of an proposed method the computer simulation have been performed using turbo code in gaussian channel environment.

• Korean Journal of Microbiology
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• v.29 no.2
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• pp.80-84
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• 1991

We cloned and expressed hepatitis B viral core antigen (HBcAg) gene in E. coli using $P_{L}$ promoter system. For optimal expression of the gene, we undertook the studies on the effects of the distance between Shine-Dalgarno (SD) sequence and start codon, copy number of repressor gene, induction temperature, and the stability of the core antigen. The results demonstrated that the induction at 37.deg.C was more efficient than at 42.deg.C, and the 11 base pairs (bp) distance between SD sequence and start codon of HBcAg gene was more efficient than the 15 bp distance in E. coli. The copy number of cI857 repressor gene did not influence on the expression of HBcAg, and the expression level of HBcAg in mutant type (low protease activity) and wild type strains was almost the same. The produced core antigen appeared to be HBcAg not HBeAg judged by two different radioimmunoassat (RIA) kits. This result suggested that the antigen was stable in E. coli.i.

• Bulletin of the Korean Chemical Society
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• v.15 no.10
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• pp.857-860
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• 1994

We have calculated the ${\pi}$-electron density, atom self-polarizability, and free valence on each atom of N-(2-chlorobenzyl)-pyridinium, N-(benzyl)-2-chloropyridinium, and N-(2-chlorobenzyl)-2-chloropyridinium salts using a simple Huckel method in order to discuss their intramolecular photocyclization reaction in a qualitative method. Our calculation qualitatively predicts that photocyclization occurs through forming radicals as a reaction intermediate by breaking a C-Cl bond after photoexcitation into a triplet state via intersystem crossing from an initially excited singlet state. We noticed that this C-Cl bond breaking is aided by ${\pi}$-complex formation between a chlorine atom and the ${\pi}$ -electrons of the neighboring ring in the triplet state and a stronger ${\pi}$-complex bond makes C-Cl bond breaking, i.e., radical formation, much easier. A chlorine atom will form a stronger ${\pi}$ -complex bond to a benzyl ring of N-(benzyl)-2-chloropyridinium than a pyridinium ring of N-(2-chlorobenzyl)-pyridinium because the former can donate its ${\pi}$-electron more easily than the latter. The chlorine at position 15 of N-(2-chlorobenzyl)-2-chloropyridinium salt in the excited state also provides its ${\pi}$-electron to the benzyl ring. So this ${\pi}$-electron can increase the bond strength of the $\pi-complex.$ Therefore, the strength of ${\pi}$-complex follows the order of N-(2-chlorobenzyl)-2-chloropyridinium, N-(benzyl)-2-chloropyridinium, and N-(2-chlorobenzyl)-pyridinium salts and thus the radical formation rate. This provides us with an intramolecular photocyclization reaction rate of the same order as given above.

• Imaging Science in Dentistry
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• v.39 no.1
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• pp.7-11
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• 2009

Purpose: The purpose of this study was to assess the prevalence and radiographic characteristics of the nuchal ligament ossification on lateral cephalometric radiographs in Koreans. Subjects and Method: I review and interpreted the lateral cephalometric radiographs from 4,558 patients (1,857 males and 2,701 females, age range from 2 to 79 years) who visited the Kyungpook National University Dental Hospital from January 1, 2008 to February 3, 2009. I grouped the shapes of nuchal ligament ossification as round, rod-like, and segmented shape. And localized the ossification as the involvement of anterior cervical vertebral body. The data were analyzed by using chi-squared test with two-tailed and at a 5% significance level. Results: Among those who showed the nuchal ligament ossification, he mean age of the 143 males was 51.1 and that of the 97 females was 48.0 years. It as not observed completely below teens, and was observed 1% in twenties, 6.1% in thirties, 18.6% in forties, and 26.3% over fifties. It was significantly prevalent in older age group (P<0.01) and in males than females among the same age group (P<0.05). The shapes of nuchal ligament ossification were as follows in order of frequency: rod-like (49.2%), round (30.4%), and segmented (20.4%). The highest involvement of ossification as found at the level of C5 (67.9%), C4 (29.2%), C6 (22.9%), C3 (3.3%), C7 (2.9%), C2 (0.8%), and C1 (0.4%). Conclusion: The nuchal ligament ossifications on lateral cephalometric radiographs were showed as round, rod-like, or segmented shape. The nuchal ligament ossification is often observed after the age of 40 and is observed more frequently in males than females. The highest shape of nuchal ligament ossification was rod-like shape and the highest involvement of cervical spine was C5.

• Journal of Microbiology and Biotechnology
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• v.5 no.1
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• pp.14-17
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• 1995

Endoglucanase gene of Pseudomonas sp. LBC505 was previously cloned in pUC19 to yield plasmid pLCl. The Pseudomonas sp. LBC505 endoglucanase gene was subcloned in a temperature-regulated Es-cherichia coli expression vector, pAS1, containing the leftward promoter $P_L$ of bacteriophage lambda. The level of gene expression was controlled by the thermal inactivation of the heat-sensitive lambda cI857 repressor. Best yield of endoglucanase was obtained by lowering the incubation temperature to $37^{\circ}C$ after induction at $42^{\circ}C$ for 1h. Under these conditions enzyme production continued for about 5h at a gradually decreasing rate. Ecoli harboring recombinant plasmid pASC10 expressed 4.3 times as much CMCase activity as E.coli containing pLCl. To enhance the expression level of endogl, ucanase gene, we have also changed the presumptive Shine-Dalgamo sequence (AGAGGT) of the gene to consensus sequence (AGGAGGT) by site-directed mutagenesis. The genes mutated were subcloned in pASl resulting in the formation of recombinant plasmid pASS50. E.coli harboring the plasmid pASS50 expressed 6.2-fold higher levels of CMCase activity than that of E.coli harboring pLC1.