Jae-An Chun
Dong-a University
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Featured researches published by Jae-An Chun.
Planta | 2003
Jae-An Chun; Un-Ho Jin; Jin-Woo Lee; Young-Byung Yi; Nam-In Hyung; Myung-Hwa Kang; Jae-Ho Pyee; Mi Chung Suh; Churl-Whan Kang; Hong-Yeol Seo; Shin-Woo Lee; Chung-Han Chung
Abstract. A cDNA (SeMIPS1) encoding myo-inositol 1-phosphate synthase (EC 5.5.1.4) (MIPS) has been characterized from sesame (Sesamum indicum L. cv. Dan-Baek) seeds and its functional expression analyzed. The SeMIPS1 protein was highly homologous with those from other plant species (88–94%), while a much lower degree of sequence homology (53–62%) was found with other organisms such as humans, mouse, algae, yeast, Drosophila, bacteria and other prokaryotes. A yeast-based complementation assay in yeast mutants containing a disrupted INO1 gene for yeast MIPS confirmed that the SeMIPS1 gene encodes a functional MIPS. Phylogenetic analysis suggested that the SeMIPS1 gene diverged as a different subfamily or family member. Southern hybridization revealed several copies of the SeMIPS1 gene present in the sesame genome and northern blotting indicated that expression of the SeMIPS1 gene may be organ specific. Salt stress during sesame seed germination had an adverse influence on transcription of SeMIPS1 and greatly reduced transcript levels as the duration of exposure to a saline environment increased and NaCl concentration increased. Germination initiation of sesame seeds was severely delayed as NaCl level increased. These results suggest that expression of SeMIPS1 is down-regulated by salt stress during sesame seed germination.
Journal of Plant Biology | 2008
Young-Min Goo; Hyun Jin Chun; Tae-Won Kim; Cheol-Ho Lee; Mi-Jeong Ahn; § Shin-Chul Bae; Kang-Jin Cho; Jae-An Chun; Chung-Han Chung; Shin-Woo Lee
In plants ascorbic acid (AsA) is a strong antioxidant or reductant that can be converted to dehydroascorbate (DHA) by oxidation. DHA, a very short-lived chemical, can either be hydrolyzed irreversibly to 2,3-diketogulonic acid or recycled to AsA by dehydroascorbate reductase (DHAR).DHAR cDNA, isolated from sesame hairy roots, was inserted into two plant expression vector syrtems with theCaMV35S promoter (CaMV35S : :DHAR) and a potato tuber-specific promoter,Patatin (Patatin : :DHAR). Southern and northern blot hybridization analyses indicated thatDHAR cDNA was successfully integrated into the potato genome and actively transcribed. High levels of sesameDHAR transcript and DHAR enzyme activity were determined, by thePatatin promoter, in regenerated potato tubers, but their levels in leaves were very low. In contrast, much higher amounts of transcript were accumulated in the leaves of CaMV35S : :DHAR regenerants than in the tubers while the activity of DHAR enzyme was higher in the latter. AsA content in the tubers of Patatin : :DHAR transgenic lines was also increased (1.1- to 1.3-fold) compared with that of non-transgenic plants. However, this was not true for the transgenic leaves. In contrast, theCaMV35S promoter was associated with AsA accumulations in both the tubers (up to 1.6-fold) and the leaves (up to 1.5-fold). However, more detailed analyses indicated that this increased enzyme activity was not always accompanied by an elevation in AsA content from transgenic plants. This suggests that other factors may limit the accumulation of vitamin C via ascorbate-recycling in transgenic potato plants.
Biotechnology and Bioprocess Engineering | 2007
Jae-An Chun; Woo-Hyup Lee; Mi-Ok Han; Jin-Woo Lee; Young-Byung Yi; Gun-Yong Park; Chung-Han Chung
The effects of various abiotic factors, including polyethylene glycol (PEG), silver nitrate (AgNO3) and potassium phosphate (KH2PO4) on biomass growth, extracellular production of recombinant fungal phytase and its transcription activity by realtime RT-PCR were examined with transformed sesame hairy roots. The PEG treatments decreased both biomass growth (80.5≈82.3%) and phytase production (82.1≈96.4%) at all concentrations tested, except 1.0 g/L PEG, which increased biomass growth to 112.4% of that of the control. The AgNO3 treatments also resulted in reduced biomass growth (77≈92%) and phytase production (84.4≈96.3%) at all concentrations applied except 1.5 mg/L AgNO3, at which biomass was increased to 109.6% of that of untreated roots. The potassium phosphate treatments increased biomass growth, production of recombinant fungal phytase and its transcription until a concentration of 340 mg/L was attained, and at 510 mg/L a rapid decrease was observed in all of the aforementioned parameters. Combined treatments of PEG (1 g/L) and AgNO3 (1.5 mg/L) exhibited both positive and negative influences on biomass growth and production and transcription of the recombinant fungal phytase when medium containing 170 and 340 mg/L of potassium phosphate were used, respectively. The addition of PEG alone to culture medium containing potassium phosphate at both of the aforementioned concentrations decreased biomass while increasing production and transcription of recombinant fungal phytase. Conversely, the addition of AgNO3 alone to culture medium increased biomass but decreased production and transcription of fungal phytase. Throughout these experiments, the most effective treatment for enhanced biomass growth, and enhanced production and transcription of recombinant fungal phytase was attained when the 1 g/L PEG and 1.5 mg/L AgNO3 were combined in medium containing 340 mg/L potassium phosphate.
Preparative Biochemistry & Biotechnology | 2009
Jae-An Chun; Jai-Heon Lee; Young-Byung Yi; G.-Y. Park; Chung-Han Chung
Abstract Using hypocotyl and cotyledon of sesame seedlings, hairy root cultures were established and cDNA coding for a peroxidase was cloned from the roots. The frequency of sesame hairy root formation was higher in hypocotyl (33.4%) than cotyledon (9.3%). Applicable levels of kanamycin and hygromycin as a selectable marker were 100 µg/mL and 30 µg/mL, respectively. The peroxidase cDNA showed relatively high sequence identity with and similarity to plant class III peroxidase family. The cDNA encoded polypeptide was identified with the presence of three sequence features: 1) the putative 4 disulfide bridges, 2) an ER-targeted signal sequence in the N-terminus, and 3) two triplets, NXS for glycosylation. A real-time RT-PCR exhibited an abrupt increase in the peroxidase transcription activity after 4-week cultures of the sesame hairy roots and its highest level in 6-week cultured hairy roots. In contrast, the growth pattern of sesame hairy roots showed a typical sigmoidal curve. The active hairy root growth began after 2-week culture and their stationary growth phase occurred after 5-week culture. These results suggested that the peroxidase expression patterns at its transcription level could be used a potential indicator signaling a message that there will be no longer active growth in hairy root cultures. The sesame peroxidase gene was differentially expressed in different tissues.
Journal of Life Science | 2009
Jae-An Chun; Jin-Woo Lee; Young-Byung Yi; Seong-Sig Hong; Kang-Jin Cho; Chung-Han Chung
Recently, hydroxymethylfurfrual (HMF) has been highlighted as a key intermediate for the production of liquid biofuels and other valuable compounds. We used sesame roots as a biocatalyst to synthesize HMF using flask cultures. The synthesis of HMF was identified by GC-mass analysis. The highest root growth was observed in cultures with 1.0 mg/l NAA at , while root growth was not found in those without NAA treatment. When silver nitrate () was added, the root growth was greatest in those treated with 0.5 mg/l and cultured at . In the case of HMF synthesis, its highest yield was obtained in those treated with 0.5 mg/l NAA at , but low HMF was detected in those treated without naphthaleneacetic acid (NAA). The addition of to the culture medium showed a 8-10% reduction in HMF yield compared to that of the control, indicating its inhibitory effect on the synthesis of HMF. On the whole, an optimal culture temperature for HMF synthesis seemed to be between .
Starch-starke | 2010
Jae-An Chun; Jin-Woo Lee; Young-Byung Yi; Seong-Sig Hong; Chung-Han Chung
Korean Journal of Chemical Engineering | 2010
Jae-An Chun; Jin-Woo Lee; Young-Byung Yi; Seong-Sig Hong; Chung-Han Chung
Process Biochemistry | 2005
Un-Ho Jin; Jae-An Chun; Mi-Ok Han; Jai-Heon Lee; Young-Byung Yi; S.W. Lee; Chung-Han Chung
Protein Expression and Purification | 2004
Un-Ho Jin; Jae-An Chun; Jin-Woo Lee; Young-Byung-Yi; Shin-Woo Lee; Chung-Han Chung
Journal of Agricultural and Food Chemistry | 2007
Jae-An Chun; Woo-Hyup Lee; Mi-Ok Han; Jin-Woo Lee; Young-Byung Yi; ‡ Young-Min Goo; Shin-Woo Lee; § Shin-Chul Bae; § and Kang-Jin Cho; Chung-Han Chung