• Korean Journal of Microbiology
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• v.47 no.1
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• pp.92-96
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• 2011

Rhodococcus sp. strain DK17 possesses three megaplasmids (380 kb pDK1, 330 kb pDK2, and 750 kb pDK3). The alkylbenzene-degrading genes (akbABCDEF) are present on pDK2 while the phthalate operons which are duplicated are present on both pDK2 (ophA'B'C'R') and pDK3 (ophABCR). DK17 with an optimal temperature of $30^{\circ}C$ showed no growth at $37^{\circ}C$. When transferred to $30^{\circ}C$, however, the $37^{\circ}C$ culture began to grow immediately, indicating that $37^{\circ}C$ is not lethal but stressful for DK17 growth. In addition, when exposed to $37^{\circ}C$ even for a short time, a part of DK17 cells lost the ability to degrade o-xylene (a model compound of alkylbenzenes). When two hundred colonies were randomly selected for colony PCR for pDK2-specific akbC, ophC', or pDK3-specific ophC, a total of 29 colonies were found to have lost at least one of the three genes. PFGE analysis clearly showed that all the mutants have different megaplasmid profiles from that of DK17 wild type, which are divided into five different cases: Type I (10 mutants, pDK2 loss and acquisition of a new ~700 kb plasmid), Type II (9 mutants, pDK2 loss), Type III (8 mutants, pDK3 loss and acquisition of a new ~400 kb plasmid), Type IV (1 mutant, pDK3 loss), and Type V (1 mutant, pDK2 and pDK3 loss and acquisition of the ~400 kb and ~700 kb plasmids). The above results showing that growth temperature changes can induce physical changes in bacterial genomes suggest that environmental changes in habitats including temperature fluctuations affect significantly the evolution of bacteria.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.142-147
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• 1989

Six plasmids of B. thuringiensis serovar. kurstaki HD73 were detected, with approximate sizes of 7.4, 7.8, 8.1, 11.3, and 75 Kb, as well as a low copied plasmid of similar length to 75 Kb. Partially cured mutants from B. thuringiensis HD73 were obtained either by the treatment of the curing agent, ethidium bromide(0.02 $\mu\textrm{g}$/$m\ell$) or by spontaneous curing, Acrystalliferous mutants(Cry$^-$) were identified by microscopic observation and immunoblotting with polyclonal antibody against 133 KD deltaendotoxin of HD73. Ten Cry$^-$ mutants were found to be lack of 75 Kb plasmid. These results implicated that this plasmid was associated with delta-endotoxin production, After isolating the mutants, we streaked them on potato dextrose agar, spizizen casamino acid glucose, starch agar, and nutrient agar. Only on starch agar medium did morphologies of Cry$^-$ appear translucent and light greyish. On the other hand, the mutants of B. thuringiensis isolated from Korean soil, designated KBS722, were obtained by the treatment of novobiocin (3 $\mu\textrm{g}$/$m\ell$). Acrystalliferous mutants of KBS722 were less translucent than HD73 mutants' only on nutrient agar medium. Compared the plasmid profile of the mutants with delta-endotoxin production, the results seemed to indicate that the insecticidal protein gene of B. thuringiensis isolates KBS722 located on about 225 Kb plasmid DNA.

• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.49-53
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• 2010

Disease control efficacy was evaluated with use of Bacillus subtilis KB-401 against cucumber powdery mildew in a greenhouse and fields. B. subtilis KB-401 showing inhibitory effect on mycelial growth of various phytopathogenic fungi was formulated for the evaluation. The formulated biofungicide of B. subtilis KB-401 was less effective at 1,000 times dilution rate than that at 250 or 500 times dilution rate. The powdery mildew was successfully controlled by the biofungicide at the early stage of disease development. The field performance of the biofungicde was conducted in Asan and Cheonan city. Three or four consecutive applications of the biofungicide at 500 dilution rate with 10-day intervals resulted in considerable efficacy of disease control as high as 83.3%.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.249-253
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• 2016

The inky cap, Coprinellus congregatus, produces several laccase isozymes during its life cycle: both hyphal tip laccase and sclerotial laccase are involved in the fungal development. When this fungus was transferred to an acid liquid medium (pH 4.0-4.5), a new laccase was synthesized and secreted into the culture supernatant. In order to examine its regulation by external pH, green fluorescent protein gene was ligated at the downstream of the promoters having different lengths. These expression vectors having different promoter lengths were inserted into the fungal transformation vector, pBARGEM7-1. These expression vectors were introduced to the mating type a1 and a2 monokaryons, and the transformants were selected by the phosphinothricin resistance. Transformant a1 (a1TF) and transformant a2 (a2TF) were mated with each other to generate homozygotic dikaryon transformants. All these transformants were grown in neutral liquid medium for 5 days, and then the whole cell homogenates were transferred to the acidic liquid medium (pH 4.1). After 36 h incubation at $25^{\circ}C$, cells were harvested for the analysis of GFP expression. GFP expression was detected in the transformant having full-length promoter (2.0 kb), but other transformants having shorter length promoter (shorter than 1.29 kb) failed to show the fluorescence. Therefore, the acid-responsive element in the laccase promoter should be localized between -2.0 kb ~ -1.29 kb region.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.474-478
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• 2005

This study was conducted to analyze genetic characteristics and to develop the specific marker for Cheju native horse (Coo) at the level of sequence characterized amplified regions (SCARs). We collected blood samples from Cheju native horse and Thoroughbred horse (Th) and obtained genomic DNA from the blood of 50 individuals randomly selected within the breeds. Seven hundred primers were chosen randomly and were used to examin the polymorphism and 40 kinds of primers showed polymorphic RAPD band patterns between two breeds. Thirty primers of them showed horse specific bands. With the primer MG 30, amplified band of 2.0 kb showed the specificity to Cheju native horse (Cnh). Additionally MG 53 detected the thoroughbred horse (Th) specific markers at size of 2.3 kb. As the next, 2.3 kb band from MG 53 was checked with the all individuals from all the breeds of this study, and it maintained the reproducible breed specificity to thoroughbred horse (Th). With this results, 2.3 kb band was cloned into plasmid vector and sequenced bidirectionally from both ends of the cloned fragment. With the obtained sequences 10 nucleotide extended primers including the original arbitray primer were designed as a SCARs primer. Finally, the primer with extended sequence showed the reproducible breed differentiation pattern and it was possible to identify Cheju native horse (Cnh) from other breeds. The SCARs marker 2.3 kb from MG 53 could be used to identify Cheju native horse (Cnh) for not only registration but also horse breeding programe.

• Journal of Biosystems Engineering
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• v.37 no.1
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• pp.1-10
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• 2012

Purpose: The most important element of an agricultural helicopter is the rotor blade realizing lift force. In order to improve the performance of the rotor blades, two types (KA152313 and KB203611) of airfoils were designed and compared. Methods: The nose shape of the KB203611 airfoil was 'drooped' and 'sharp' compared to the leading edge of the KA152313 airfoil. The performance of the experimental airfoils was simulated using CFD-ACE program, and lifts were measured in situ using the 'AgroHeli-4G', a prototype helicopter. Results: Simulated lifts of the blade with the KA152313 airfoil showed proper values for a wide range of angles of attack between $14^{\circ}{\sim}18^{\circ}$, while the simulated lift of the KB203611 blade exhibited maximum values near $13^{\circ}{\sim}14^{\circ}$. In the lift measurements, the range of operable angles of attack was a collective pitch angle at the grip (GP) of $12^{\circ}{\sim}18^{\circ}$ for the KA152313 blade. On the other hand, the range of angles of attack for the KB203611 blade was a GP of $12^{\circ}{\sim}14^{\circ}$. Conclusions: The blade of KA152313 performed well over a wide range of AoAs and the blade of KB203611 performed better at low AoAs. In this study, a variative airfoil blade, gradually emerging from grip to tip using the two different airfoils, was suggested.

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.230-234
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• 2002

To describe characteristics of a hemolysin in mosquitocidal Bacillus thuringiensis subsp. gyangiensis strain 21-2, Escherichia coli HB101 was transformed with a gene encoding hemolysin in the strain 21-2. Transformant 47 con-tained 2.5 kb DNA was selected by ELISA, immunoblot and DNA electrophoresis. Transformant 47-5 was recon-structed after digestion of the 2.5 kb DNA with Hind m. Transformant 47-5 contained 1.8 kb DNA and expressed 23 kDa Protein which had mosquitocidal activity to Aedes aegypti. The 23 kDa Protein itself in vitro didn't show hemolytic activity on human erythrocytes, but the protein had the activity after proteinase K treatment.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.2
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• pp.134-138
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• 1994

Potato Virus Y(PVY), vein necrosis strain, in Korea causes severe symptoms on burley tobacco(Nicotiana tabacum L.). As the results, programs to incorporate PVY resistance into commercial cultivars were initiatEd. But the development of the homozygous fertile line resistant to PVY is time consumming. This study was conducted whether the Fl hybrid could be used to reduce the yield losses caused by PVY. Four F1 hybrids were made between male - sterile(ms) NC 107 and KB 107 as maternal parent, and TC 612 and TC 613 as Pollen donor, respectively, and were evaluated for their PVY resistance and negatively associated traits. (ms NC 107 X TC 612) F1, named as KB 109, Ivas applied to yield trial and compared with commercial cultivars for the level of disease resistance, agronomic characteristics, chemical contents and physical properties. All Fl hybrid could be used commercially as the PVY resistant cultivar. Especially KB 109 have the resistance against PVY, tobacco mosaic virus and black shank(Phytophthora parasitica var. nicotianae). It had wider leaves, flowered one day later, and yield of acceptable quality was higher than that of Burley 21, standard cultivar in Korea.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.655-659
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• 2000

A 11.5-kb DNA fragment containing an endo-inulinase gene was cloned from Xanthomonas oryzae #5. It contained a single open reading frame of 3,999bp, encoding a polypeptide composed of signal peptide of 32 amino acids and mature protein of 1,301 amino acids. From the comparison of amino acids sequences with fructan hydrolases, inulinase, levanase and CFTase, the sequence of the endo-inulinase had highly homology of 72% with CFTase of B. circulans, and six highly conserved regions including the ${\beta}-fructosidase$ motif were found.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.08a
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• pp.142-147
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• 1998

Recently, 8 kb/s CS-ACELP coder of G.729 is atandardized by ITU-T SG15 and it has been reported that the speech quality of G729 is better than or equal to that of 32kb/s ADPCM. However G.729 is the fixed rate speech coder, and it does not consider the property of voice activity in mutual conversation. If we use the voice activity, we can reduce the average bit rate in half without any degradations of the speech quality. In this paper, we propose an efficient variable rate algorithm for G.729. The variable rate algorithm consists of two main subjects, the rate determination algorithm and algorithm, we combine the energy-thresholding method, the phonetic segmentation method by integration of various feature parameters obtained through the analysis procedure, and the variable hangover period method. Through the analysis of noise features, the 1 kb/s sub rate coder is designed for coding the background noise signal. So, we design the 4 kb/s sub rate coder for the unvoiced parts. The performance of the variable rate algorithm is evaluated by the comparison of speed quality and average bit rate with G.729. Subjective quality test is also done by MOS test. Conclusively, it is verified that the proposed variable rate CS-ACELP coder produced the same speech quality as G.729, at the average bit rate of 4.4 kb/s.