• Journal of Life Science
• /
• v.11 no.4
• /
• pp.316-320
• /
• 2001

Sonication tremendously improves the efficiency of Agrobacterium infection by introducing small and uniform fissures and channels throughout the targeted tissue. Using shoot tips of cotton as explants, the effect of sonication treatment and virulence genes in Agrobacterium tumefaciens on transformation efficiency was investigated. The pat gene which encodes resistance to the herbicide, glufosinate, was used as a selectable marker. Transformation efficiency was evaluated on th basis of survival rates of cocultivated shoot tips on selection medium containing 2.5 mg/l gulfosinate-ammonium(ppt) adn 25. mg/l Clavamax. Sonication from 5 to 15 second has a positive effect on shoop tip survival. However, whil virE as well as virG or vir GN54D showed an enhancement in transformation efficiency, virE,. virG resulted in the most significant enhancement. Overall, the combination of additional virG/virE gene and sonication treatment resulted in the most significant increase in transformation efficiency.

• Journal of Microbiology
• /
• v.37 no.3
• /
• pp.175-179
• /
• 1999

To elucidate the role of vir-box in the expression of the virE gene, the vir-box was modified by site-directed mutagenesis and tested for ${\beta}$-galactosidase activities. A, C, T T, A, C substitutions at -62, -63, and -65 positions, destroying the 5'-region of the vir-box and A T at position -55, destroying the 3'-region of the vir-box respectively, showed only 17% promoter activity. When the vir-box was modified to contain perfect dyad symmetry structure (DSR) by the substitutions T, G A, T at -60 an d-61 positions, ${\beta}$-glactosidase activity increased 302%. These results indicate that the 5' and 3'-region of vir-box as well as the imperfect DSR of the vir-box itself may play a very important role in the regulation of virE gene expression.

• Journal of Plant Biology
• /
• v.34 no.4
• /
• pp.331-339
• /
• 1991

To elucidate the regulatory mechanism of virE operon from vir regions (virA, virB, virC, virD, virG, virE) of pTiA6 which have been known to be essential for efficient crown gall tumorigenesis in plants, the activity of the truncated virE, promoter was analyzed. pSM358cd, a recombinant plasmid in which virE :: Tn3-HoHo1 (Tn3-promoterless lacZ) was cloned into SalI site of pVK102, was digested with SalI, and virE :: Tn3-HoHo1 was seperated from pVK102. To construct the truncted virE recombinant plasmids (pJS031, pJS051, pJS102, pJS201, pJS301), 5'-end of vireE promoter was deleted with BAL31 and cloned into pVK102 and then transferred into a. tumefaciens A348(pTiA6). According to the activity of the truncated virE promoter in recombinant plasmids, they were classified into two groups, pJS031, pJS051, pJS101 and pJS201 belong to a functional group and pJS301 is a non-functional. The size of deleted nucleotides of pJS201 and pJS301 seemed to be about 130 nucleotides and about 250 nucleotides from 5'-end of virE promoter, respectively. Hence it was thought that the essential site of the virE promoter was located between about 130th nucleotide and 250th nucleotide from 5'-end of the virE promoter.

• Korean Journal of Plant Tissue Culture
• /
• v.27 no.1
• /
• pp.7-12
• /
• 2000

Explants of lettuce (Lactuca sativa L.) were co-cultivated with Agrobacterium tumifacience GV 3101 strain containing nptII gene and cold regulated gene (BN115) from Brassica napus for transformation. Multiple shoots were obtained from the explants in the selection medium (MS basal medium supplemented with 100 mg/L kanamycin, 500 mg/L carbenicillin, 0.1 mg/L NAA, 0.5 mg/L kinetin) after 3 to 4 weeks of co-culture. The putative transgenic shoots were transferred to rooting medium (1/2 MS basal medium supplemented with 100 mg/L kanamycin and 250 mg/L carbenicillin). The selected shoots were tested with PCR analysis using nptll, BN115 primers whether cold-regulated gene was introduced to genome of the plants. The vir G primers were particularly used to check contamination of Agrobacterium during PCR analysis. The nptII and BN115 primers produced the specific PCR bands in the putative transgenic lines but the vir G primers did not. These results confirmed that the PCR products were not the result of contamination with Agrobacterium. Additionally the Southern analysis of the PCR products and RT-PCR analysis proved that the cold-regulated gene was successfully integrated and transcribed in the putative transgenic lettuce plants.

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10b
• /
• pp.324-324
• /
• 1995

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 2000.10a
• /
• pp.135.3-135
• /
• 2000

No Abstract, See Full Text

• Journal of Microbiology and Biotechnology
• /
• v.17 no.10
• /
• pp.1616-1621
• /
• 2007

We have established a SYBR Green-based realtime PCR method using AnyDirect solution, which enhances PCR from whole blood, for direct amplification of the virA gene of Shigella flexneri and the invA gene of Salmonella typhimurium from human feces without prior DNA purification. When we compared the efficiency of conventional or realtime PCR amplification of the virA and invA genes from the supernatant of boiled feces supplemented with S. flexneri and S. typhimurium in the presence or absence of AnyDirect solution, amplification products were detected only in reactions to which AnyDirect solution had been added. The detection limit of real-time PCR was $1{\times}10^4\;CFU/g$ feces for S. flexneri and $2{\times}10^4\;CFU/g$ feces for S. typhimurium; this sensitivity level was comparable to other studies. Our real-time PCR assay with AnyDirect solution is simple, rapid, sensitive, and specific, and allows simultaneous detection of S. flexneri and S. typhimurium directly from fecal samples without prior DNA purification.

• Publications of The Korean Astronomical Society
• /
• v.30 no.2
• /
• pp.219-221
• /
• 2015

We present our recent observations of SDSS J102102.25+174439.9, a new eclipsing white dwarf - main sequence WDMS binary with an orbital period of 0.14 days. This system belongs to the post common-envelope binary group as shown by the spectrum from the Sloan Digital Sky Survey. We obtained our data using the ULTRASPEC instrument installed on the 2.4-m telescope at the Thai National Observatory (TNO). Our multi-band observations reveal an unusual and persistent drop in brightness after the primary eclipse. These dips, which appear to show variations in amplitude, also have a complex shape that changes within days. Dips in WDMS systems have been observed on only one other occasion, in the light curve of QS Vir prior to the eclipse of the white dwarf. The dips in SDSS J1021+1744 are unique because they are present at different wavelengths and they occur approximately at similar phases. Hosting a DA white dwarf and an M4 companion star, this system is known to be the only WDMS to show these kind of dips in its light curve. It is possible that these dips are caused by ejected materials from an active companion star, such as in QS Vir. The light curve in the g' filter exhibits deep and narrow features, implying that the material which passes in front of the white dwarf in SDSS J1021 must be dense and small in size. Furthermore, we try to constrain the stellar and orbital parameters of SDSS J1021+1744 using the Binary Maker 3 software. We use g' and r' data for our light curve analysis to have a better approximation for the red dwarf star.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.120.2-120
• /
• 2003

Agrobacterium vitis is a causal agent of crown-gall disease on grapevine. In Korea, grapevine variety (GeoBong) have severely been infected by the bacteria since stems of the variety were buried in soil for overwintering. Infection ratio over 70-80％ was observed on 7 years old GeoBong grapevine in Ansung and Cheonan. PCR specific primers for A. vitis strains were designed using nucleotide sequences of vir A gene in Ti-Plasmid, pheA gene in chromosomal DNA and a URP-PCR polymorphic band. Three hundred bacterial strains were isolated from the different 80 galls formed on GeoBong grapevine in Cheonan and Ansung of Korea and were screened to identify A. vitis using the three specific PCR primers for Agrobacterium vitis. Twenty-four bacterial strains that are detected by the primers were further confirmed by pathogenicity and biochemical methods. To investigate the genomic diversity of the bacterial strains, twenty primers of 20 mer referred to universal rice primers (URP) were applied for PCR fingerprinting, Of them, URP2R and URP2F primers could effectively be used to detect polymorphism within the bacterial strains.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.143.1-143.1
• /
• 2012

We attempt to investigate the main reason of the asymmetrical light curves of contact and near-contact eclipsing binary base on the hypothesis that cool spot was produced on late type star while hot spot was produced from transferred material from their companion star hitting surface. We select 7 eclipsing binary systems which showed asymmetric light curves and mass transfer. Period variation and mass transfer rate were obtained from O-C diagram. Radial velocity curves and light curves of those 7 eclipsing binary system were adopted from available literature in order to obtain the absolute dimension. For four contact eclipsing binary system (AD Phe, EZ Hya, AG Vir and VW Boo), their component stars belonged to spectral type G to K was fitted by cool spot model. While the other two near-contact systems (RT Scl and V1010 Oph) and one contact system (SV Cen) was fitted by cool spot model. The densities of the materials are adopted from stellar model which calculate by stellar structure code. The calculated spot temperature turns out to agree with the photometric solution but there are no correlate between period variation rate and type of spot.