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Kim S.-H.,Chonnam National University | Yoo S.-J.,Chonnam National University | Min K.-H.,Chonnam National University | Nam S.-H.,Jeonnam Agricultural Research and Extension Services | And 2 more authors.
Biochemical and Biophysical Research Communications | Year: 2013

Polyamines in plants are involved in various physiological and developmental processes including abiotic and biotic stress responses. We investigated the expression of ADCs, which are key enzymes in putrescine (Put) biosynthesis, and roles of Put involving defense response in Arabidopsis. The increased expression of ADC1 and ADC2, and the induction of Put were detected in GVG-NtMEK2DD transgenic Arabidopsis, whereas, their performance was partially compromised in GVG-NtMEK2DD/mpk3 and GVG-NtMEK2DD/mpk6 mutant following DEX treatment. The expression of ADC2 was highly induced by Pst DC3000 inoculation, while the transcript levels of ADC1 were slightly up-regulated. Compared to the WT plant, Put content in the adc2 knock-out mutant was reduced after Pst DC3000 inoculation, and showed enhanced susceptibility to pathogen infection. The adc2 mutant exhibited reduced expression of PR-1 after bacterial infection and the growth of the pathogen was about 4-fold more than that in the WT plant. Furthermore, the disease susceptibility of the adc2 mutant was recovered by the addition of exogenous Put. Taken together, these results suggest that Arabidopsis MPK3 and MPK6 play a positive role in the regulation of Put biosynthesis, and that Put contributes to bacterial pathogen defense in Arabidopsis. © 2013 Elsevier Inc.


Nguyen T.T.H.,Chonnam National University | Moon Y.-H.,Audubon Sugar Institute | Ryu Y.-B.,Korea Research Institute of Bioscience and Biotechnology | Kim Y.-M.,Korea Research Institute of Bioscience and Biotechnology | And 4 more authors.
Enzyme and Microbial Technology | Year: 2013

The human fibroblast collagenase catalytic domain (MMP1ca) that is considered a prototype for all interstitial collagenase and plays an important role in the turnover of collagen fibrils in the matrix was expressed as an inclusion body in the Escherichia coli. The purified enzyme displayed activity with substrate Dnp-Pro-Leu-Ala-Leu-Trp-Ala-Arg-OH with a Km value of 26.61±1.42μM. The inhibition activity of the nine flavonoid compounds and gallic acid against MMP1ca was examined. Among the compounds tested, the IC50 of seven flavonoid compounds were determined and ranged from 14.13 to 339.21μM. Epigallocatechin gallate (EGCG) showed the highest inhibition toward MMP1ca with IC50 values of 14.13±0.49μM. EGCG showed a competitive inhibition pattern with a Ki value of 10.47±0.51μM. The free binding energy of EGCG against MMP1ca was -13.07kcalmol-1, which was calculated by using Autodock 3.0.5 software and showed numerous hydrophobic and hydrogen bond interactions. The galloyl group of EGCG, gallocatechin gallate and epicatechin gallate was determined to be important for inhibitory activity against MMP1ca. © 2012 Elsevier Inc.


Lee J.H.,Chonnam National University | Nam S.H.,Jeonnam Agricultural Research and Extension Services | Park H.J.,Cosmax Ltd | Kim Y.-M.,Chonnam National University | And 5 more authors.
Food Science and Biotechnology | Year: 2010

Appreciably elevated levels of dextranase from Arthrobacter oxydans (AODex) isolated from sugar-cane farm soil was resulted from the culture on the Luria- Bertani (LB) medium containing 1%(w/v) soluble starch, glycerol, or dextran. The responsible gene (aodex) was cloned, its nucleotide sequence was determined, and expression of the encoded protein was achieved in Escherichia coli. An open reading frame was composed of 1,863 bp putatively encoding a 68.3 kDa protein. Recombinant A. oxydans dextranase (rAODex) was purified about 16 fold by nickel-nitrilotriacetic acid affinity column chromatography; Km value for dextran T2000 was 0.85 mg/mL (w/v). AODex treatment of stale sugar cane juice resulted in a yield of square and light-colored sugar crystals. © KoSFoST and Springer 2010.


Cho J.-Y.,Chonnam National University | Lee H.J.,Chonnam National University | Kim G.A.,Chonnam National University | Kim G.D.,Chonnam National University | And 4 more authors.
Journal of Cereal Science | Year: 2012

γ-Oryzanol (steryl ferulates; SF) has been shown to be a major bioactive compound in rice. To determine the content of individual γ-oryzanols in brown rice by high performance liquid chromatography (HPLC), purification of individual SF for use as an external standard is required. Four main SF were isolated from a commercial γ-oryzanol mixture and identified as cycloartenyl ferulate (1), 24-methylenecycloartanyl ferulate (2), campesteryl ferulate (3), and sitosteryl ferulate (4) based on mass spectrometry and nuclear magnetic resonance spectroscopic data. The SF contents between conventional and organic brown rice were qualitatively determined by HPLC using SF isolated from a commercial γ-oryzanol mixture as the external standard. The total γ-oryzanol content (mg/100 g) in organic brown rice (65.6 ± 2.7) was slightly higher (P < 0.05) than that found in conventional brown rice (60.2 ± 1.8). The content (mg/100 g) of 1 (21.2 ± 0.9) and 4 (9.8 ± 0.4) in organic brown rice was higher (P < 0.05) than that observed in conventional brown rice (1, 18.2 ± 1.1; 4, 8.5 ± 0.3). However, the content of 2 and 3 in the conventional and organic brown rice samples did not differ significantly. These results indicate that the cultivation methods do significantly alter the γ-oryzanol content for conventional and organic brown rice. © 2012 Elsevier Ltd.


Kim G.D.,Chonnam National University | Kim G.D.,Bohea Brewery Co. | Lee Y.S.,Jeonnam Agricultural Research and Extension Services | Cho J.-Y.,Chonnam National University | And 7 more authors.
Journal of Agricultural and Food Chemistry | Year: 2010

The aim of this study was to evaluate the chemical compositions and antioxidative activities of hot pepper fruits cultivated with strict management by organic and conventional agricultural practices. The ascorbic acid content in the organically grown hot pepper (OGP) was significantly higher than that of conventionally grown hot pepper (CGP) in both green and red fruits. The content of other bioactive compounds such as flavonoids (apigenin, luteolin, quercetin) and total phenolics in OGP was typically higher than in CGP regardless of fruit color. In addition, the ABTS+ radical-scavenging activity of OGP red fruits was significantly higher than that of CGP red fruits. Moreover, regardless of the color of the fruits, a higher antioxidative activity was observed in blood plasma from rats administered the OGP fruit extracts than in blood plasma from rats administered the CGP fruit extracts. It was hypothesized that the higher antioxidant activity of the OGP fruits may have resulted from the higher antioxidant content in the OGP fruits. These results suggest that consumption of pepper fruits may increase antioxidant activity in the blood, and OGP fruits may be more effective in increasing this antioxidant activity than CGP fruits. © 2010 American Chemical Society.


Woo H.-J.,Chonnam National University | Kang H.-K.,Chonnam National University | Nguyen T.T.H.,Chonnam National University | Kim G.-E.,Samyang Genex Corporation | And 8 more authors.
Enzyme and Microbial Technology | Year: 2012

Novel ampelopsin glucosides (AMPLS-Gs) were enzymatically synthesized and purified using a Sephadex LH-20 column. Each structure of the purified AMPLS-Gs was determined by nuclear magnetic resonance, and the ionic product of AMPLS-G1 was observed at m/z 505 (C21H22O13·Na)+ using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. AMPLS-G1 was identified as ampelopsin-4'-O-α-d-glucopyranoside. The optimum condition for AMPLS-G1, determined using response surface methodology, was 70mM ampelopsin, 150mM sucrose, and 1U/mL dextransucrase, which resulted in an AMPLS-G1 yield of 34g/L. The purified AMPLS-G1 displayed 89-fold increased water solubility and 14.5-fold browning resistance compared to those of AMPLS and competitive inhibition against tyrosinase with a Ki value of 40.16μM. This value was smaller than that of AMPLS (Ki=62.56μM) and much smaller than that of β-arbutin (Ki=514.84μM), a commercial active ingredient of whitening cosmetics. These results indicate the potential of AMPLS and AMPLS-G1 as superior ingredients for functional cosmetics. © 2012 Elsevier Inc.


Kim G.H.,Sunchon National University | Song K.I.,Sunchon National University | Koh Y.J.,Sunchon National University | Jung J.S.,Sunchon National University | And 2 more authors.
Acta Horticulturae | Year: 2015

'Hayward' (Actinidia deliciosa [A. Chev] Liang et Ferguson), which has been cultivated since the late 1970s, is the most popular green kiwifruit cultivar in Korea. However, 'Hayward' has been known to be susceptible to problematic foliar diseases such as bacterial canker, bacterial leaf spot, powdery mildew and fungal leaf spot diseases on kiwifruit trees grown at open-field orchards during growing season and postharvest fruit rot diseases during storage and distribution of harvested fruits. 'Haegeum' (A. chinensis Planchon), which is one of the new yellow kiwifruit cultivars bred in recent years, has been released at growers' orchards since 2007 in Korea. Responses of 'Haegeum' against the major diseases of kiwifruit were compared with those of 'Hayward'. The disease severities of the foliar diseases of 'Hayward' and 'Haegeum' were investigated at six naturally infected orchards during the growing season in 2013. The incidence rates of the postharvest fruit rot diseases on the fruits harvested in 2012 were also investigated at two naturally infected orchards. The disease severities of bacterial canker and bacterial leaf spot diseases were 18.5 and 63.5% on 'Hayward' at an orchard, but the disease severity of bacterial canker was 1.2% and no bacterial leaf spot was observed on 'Haegeum', respectively. Furthermore the disease severities of powdery mildew ranged from 9.4 to 84.8% on 'Hayward' at four orchards, while those on 'Haegeum' were less than 20%. The disease severities of leaf spot diseases induced by several fungi were 27.4 and 5.0% on 'Hayward' and 'Haegeum', respectively. The incidence rates of postharvest fruit rot diseases were 18.5% on 'Hayward' and 3.3% on 'Haegeum'. The overall results reveal that 'Haegeum' is relatively resistant to the major diseases of kiwifruit compared with 'Hayward'.


Lee Y.H.,South Korean National Institute of Animal Science | Lee Y.H.,Seoul National University | Ko S.-J.,Jeonnam Agricultural Research and Extension Services | Cha K.-H.,Jeonnam Agricultural Research and Extension Services | Park E.W.,Seoul National University
Plant Pathology Journal | Year: 2015

A disease forecast model for bacterial grain rot (BGR) of rice, which is caused by Burkholderia glumae, was developed in this study. The model, which was named ‘BGRcast’, determined daily conduciveness of weather conditions to epidemic development of BGR and forecasted risk of BGR development. All data that were used to develop and validate the BGRcast model were collected from field observations on disease incidence at Naju, Korea during 1998-2004 and 2010. In this study, we have proposed the environmental conduciveness as a measure of conduciveness of weather conditions for population growth of B. glumae and panicle infection in the field. The BGRcast calculated daily environmental conduciveness, Ci, based on daily minimum temperature and daily average relative humidity. With regard to the developmental stages of rice plants, the epidemic development of BGR was divided into three phases, i.e., lag, inoculum build-up and infection phases. Daily average of Ci was calculated for the inoculum build-up phase (Cinf) and the infection phase (Cinc). The Cinc and Cinf were considered environmental conduciveness for the periods of inoculum build-up in association with rice plants and panicle infection during the heading stage, respectively. The BGRcast model was able to forecast actual occurrence of BGR at the probability of 71.4% and its false alarm ratio was 47.6%. With the thresholds of Cinc = 0.3 and Cinf = 0.5, the model was able to provide advisories that could be used to make decisions on whether to spray bactericide at the pre-and post-heading stage. © The Korean Society of Plant Pathology.


Kim D.-K.,Jeonnam Agricultural Research and Extension Services | Jeong S.C.,Sunchon National University | Gorinstein S.,Hebrew University of Jerusalem | Chon S.-U.,Chosun University
Plant Foods for Human Nutrition | Year: 2012

The aim of this investigation was to evaluate the biological, alcohol dehydrogenase (ADH) and antiproliferative activities of different extracts of mungbean seeds and sprouts. All extracts from the sprouts showed higher contents of total phenolics (TP), total flavonoids (TF), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than from seeds. The highest DPPH and tyrosinase inhibition activities were registered in ethyl acetate (EtOAc) extract. ADH activity of methanol (MeOH), n-hexane (n-hexane) and n-butanol (n-BuOH) extracts from sprouts was significantly higher (P < 0. 05) than from seeds. However, the highest ADH activity was found in water extract of seeds. According to 3-(4, 5-dimethylthiazol -2-yl)-2, 5-diphenyltetrazolium bromide) (MTT) assay, extracts from sprouts were more effective against Calu-6 (human pulmonary carcinoma) and SNU-601 (human gastric carcinoma) cells than from seeds. EtOAc extract showed the highest antiproliferative activity in both sprouts and seeds, followed by n-hexane extraction. During sprouting of mungbean, all the studied components significantly increased. In conclusion, the extracts of sprouts are more effective than from seeds and could be a potential source of antioxidants linked with health benefits. © 2012 Springer Science+Business Media, Inc.


Lee J.,National Academy of Agricultural Science | Park K.W.,Chungnam National University | Lee I.-Y.,National Academy of Agricultural Science | Kim C.-S.,National Academy of Agricultural Science | And 2 more authors.
Weed Research | Year: 2015

Echinochloa species are amongst the most problematic weeds in rice fields of Korea. The steady reliance on the Acetyl-CoA carboxylase (ACCase) and acetolactate synthase inhibiting herbicides for control of these weeds has led to resistance to these herbicides. The objective of this study was to assess the genetic diversity among populations of ACCase inhibitor-resistant and -susceptible Echinochloa crus-galli and E. oryzicola in Korea, to better understand their population structure and possible origins of resistance. Seven simple sequence repeat markers were applied to assess the genetic diversity between resistant and susceptible E. crus-galli and E. oryzicola from 12 populations in Korea. Genetic diversity was slightly higher in the resistant group. The Unweighted Pair Group Method using Arithmetic algorithm (UPGMA) dendrogram generated two distinct clades. One clade consisted of Echinochloa spp. from three populations, i.e. Anmyeondo, Gimje 4 and Gongju, which are resistant and differentiated from the susceptible populations, and the other clade contained the rest of the populations. Structure modelling supported two clades of UPGMA clustering. Based on these data, we can infer that some resistant populations are greatly differentiated, whereas other resistant biotypes are still building up resistance in rice fields in Korea. Resistance traits will be fixed and continue to spread over time without proper control measures. Weed Research © 2015 European Weed Research Society.

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