• Molecules and Cells
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• v.23 no.2
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• pp.161-169
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• 2007

We identified two alternatively spliced variants of the peroxisomal targeting signal 1 (PTS1) receptor protein Pex5ps in monocot (rice, wheat, and barley) but not in dicot (Arabidopsis and tobacco) plants. We characterized the molecular and functional differences between the rice (Oryza sativa) Pex5 splicing variants OsPex5pL and OsPex5pS. There is only a single-copy of OsPEX5 in the rice genome and RT-PCR analysis points to alternative splicing of the transcripts. Putative light-responsive cis-elements were identified in the 5' region flanking OsPEX5L and Northern blot analysis demonstrated that this region affected light-dependent expression of OsPEX5 transcription. Using the pex5-deficient yeast mutant Scpex5, we showed that OsPex5pL and OsPex5pS are able to restore translocation of a model PTS1 protein (GFP-SKL) into peroxisomes. OsPex5pL and OsPex5pS formed homo-complexes via specific interaction domains, and interacted with each other and OsPex14p to form hetero-complexes. Although overexpression of OsPex5pL in the Arabidopsis pex5 mutant (Atpex5) rescued the mutant phenotype, overexpression of OsPex5pS only resulted in partial recovery.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.184-189
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• 2004

Rice wine cake (RWC) is the solid waste obtained after rice wine fermentation. For the mass production of the spores of yeast Saccharomyces from RWC, the optimum pretreatment condition of RWC, the optimum composition of culture medium, and the optimum culture condition were examined. For sporulation, yeast cells were grown in the pre sporulation medium (PSM), transferred into sporulation medium (SM) containing 1 % potassium acetate, and incubated in a rotary shaking incubator at $25^{\circ}C$ for 4 days. The supernatant of the mixture of RWC and water was used as the presporulation medium (PSM). The optimum temperature and time for the pre-incubation of the mixture of RWC and water (1:2) to obtain maximum sporulation yield were $V^{\circ}C$ and 24 hr, respectively, and optimum culture time in PSM was 48 hr. Using these optimum conditions, the asci number obtained was 0.72$ 1.06${\times}$10^{8}$$m\ell$. The addition of wheat coat koji into SM increased the final number of asci to beTEX>$10^{8}$ $m\ell$. Spores were formed in the SM with the initial pH of 7-11, but no spores were formed in the SM with the initial pH of 5. To save the time and effort to pretreat the RWC, 2% and 0.5% RWC without any pretreatment were directly added into PSM containing 1 % brown sugar and SM, respectively, and the maximum asci number of $1.27${\times}$10^{8}$ /$m\ell$ was obtained.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.270-279
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• 2017

Regional assessment of crop productivity using a gridded simulation approach could aid policy making and crop management. Still, little effort has been made to develop the systems that allows gridded simulations of crop growth using ORYZA 2000 model, which has been used for predicting rice yield in Korea. The objectives of this study were to develop a series of data processing modules for creating input data files, running the crop model, and aggregating output files in a region of interest using gridded data files. These modules were implemented using C++ and R to make the best use of the features provided by these programming languages. In a case study, 13000 input files in a plain text format were prepared using daily gridded weather data that had spatial resolution of 1km and 12.5 km for the period of 2001-2010. Using the text files as inputs to ORYZA2000 model, crop yield simulations were performed for each grid cell using a scenario of crop management practices. After output files were created for grid cells that represent a paddy rice field in South Korea, each output file was aggregated into an output file in the netCDF format. It was found that the spatial pattern of crop yield was relatively similar to actual distribution of yields in Korea, although there were biases of crop yield depending on regions. It seemed that those differences resulted from uncertainties incurred in input data, e.g., transplanting date, cultivar in an area, as well as weather data. Our results indicated that a set of tools developed in this study would be useful for gridded simulation of different crop models. In the further study, it would be worthwhile to take into account compatibility to a modeling interface library for integrated simulation of an agricultural ecosystem.

• The Plant Pathology Journal
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• v.26 no.4
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• pp.313-320
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• 2010

Genetic instability of the rice blast fungus Magnaporthe oryzae has been suggested as a major factor underlying the rapid breakdown of host resistance in the field. However, little information is available on the mechanism of genetic instability. In this study, we assessed the stability of repetitive DNA elements and several key phenotypic traits important for pathogenesis after serially transferring two isolates though rice plants and an artificial medium. Using isolate 70-15, we obtained a total of 176 single-spore isolates from 10 successive rounds of culturing on artificial medium. Another 20 isolates were obtained from germ tubes formed at the basal and apical cells of 10 three-celled conidia. Additionally, 60 isolates were obtained from isolate KJ201 after serial transfers through rice plants and an artificial medium. No apparent differences in phenotypes, including mycelial growth, conidial morphologies, conidiation, conidial germination, appressorium formation, and virulence, or in DNA fingerprints using MGR586, MAGGY, Pot2, LINE, MG-SINE and PWL2 as probes were observed among isolates from the same parent isolate. Southern hybridization and sequence analysis of two avirulence genes, AVR-Pita1 and AVR-Pikm, showed that both genes were also maintained stably during 10 successive generations on medium and plants. However, one reversible loss of restriction fragments was found in the telomere-linked helicase gene (TLH1) family, suggesting some telomere regions may be more unstable than the rest of the genome. Taken together, our results suggest that phenotype and genotype of M. oryzae isolates do not noticeably change, at least up to 10 successive generations on a cultural medium and in host plants.

• Molecules and Cells
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• v.27 no.4
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• pp.467-473
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• 2009

Our previous study suggested that OsBWMK1, a gene which encodes a member of the rice MAP kinase family, generates transcript variants which show distinct expression patterns in response to environmental stresses. The transcript variants are generated by alternative splicing and by use of alternative promoters. To test whether the two alternative promoters, pOsBWMK1L (promoter for the OsBWMK1L splice variant) and pOsBWMK1S (promoter for the OsBWMK1S splice variant), are biologically functional, we analyzed transgenic plants expressing GUS fusion constructs for each promoter. Both pOsBWMK1L and pOsBWMK1S are biologically active, although the activity of pOsBWMK1S is lower than that of pOsBWMK1L. Histochemical analysis revealed that pOsBWMK1L is constitutively active in most tissues at various developmental stages in rice and Arabidopsis, whereas pOsBWMK1S activity is spatially and temporally restricted. Furthermore, the expression of pOsBWMK1S::GUS was upregulated in response to hydrogen peroxide, a plant defense signaling molecule, in both plant species. These results suggest that the differential expression of OsBWMK1 splice variants is the result of alternative promoter usage and, moreover, that the mechanisms controlling OsBWMK1 gene expression are conserved in both monocot and dicot plants.

• Journal of Plant Biotechnology
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• v.30 no.2
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• pp.135-141
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• 2003

Peroxiredoxin(Pix) are large family of peroxidases that reduce alkyl hydroperoxides and hydrogen peroxide. A cDNA clone (referred to as swPrxl) encoding Pix was from a sweetpotato cDNA library constructed from suspension-sultured cells, and its expression was investigated in terms of stress. The swPrxl contained an open reading frame (ORF) encoding mature protein of 193 amino acids with calculated molecular mass of 20.8kDa. The predicted amino acid sequence of swPrxl has two conserved cysteines that are essential resicues for the reduction of peroxides. It showed high amino acid sequence homology ot PixIIF of Arabidopsis (77%) and putative Prx of rice(72%). RNA gel-blot analysis showed that swPrxl gene was expressed dominantly in leave among intact tissues, and also highly detect in suspension-cultured cells. Interestingly, the level of swPrxl transcripts was almost the same regardless of the growth stage in suspension culture. Furthermore, the transcription level of swPrxl gene was not significantly changed in response to various stress treatments such as wounding, extreme temperature and stress-related chemicals RT-PCR analyses.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.561-567
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• 2004

The purpose of this study was to investigate the effect of Paecilomyces japonica mycelia(PJM) on pH, titrable acidity and microbiological qualify of Jeungpyun(fermented rice cake). Jeungpyun prepared with $0\~\%$ of PJM stored at $5^{\circ}C\;and\;20^{\circ}C$ for 4 weeks and 7 days respectively. Before fermentation of Jeungpyun dough, viable cells of total bacterial counts(TBC), yeasts and lactic acid bacteria(LAB) were $6.0\~9.8\times10^6,\;5.3\~9.0\times10^6,\;5.4\~8.5\times10^6\;CFU/g$, respectively. During the fermentation of dough, viable cells of TBC, yeasts and LAB increased $0.3\~0.4$ log cycle and pH was decreased whereas acidity increased as the progress of fermentation. Total viable cells in Jeungpyun before storage were $5.0\times10^1\;CFU/g$. During storage of Jeungpyun, TBC, yeasts and LAB of control group increased 2.6, 2.4, 2.1 log cycle at $5^{\circ}C$ and 4.8, 4.6, 4.5 log cycle at $50^{\circ}C$, respectively, when reached at maximum level. Major microflora of Jeungpyun was composed of yeasts and LAB during fermentation of dough and storage at $5^{\circ}C\;and\;20^{\circ}C$. Addition of PJM, inhibited the growth of microorganisms, the changes of PH and titrable acidity of Jeungpyun during storage at both of $5^{\circ}C\;and\;20^{\circ}C$. From these results, the addition of PJM extended the shelf-life of Jeungpyun during storage at $5^{\circ}C\;and\;20^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.972-977
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• 1995

The induction of phase II enzymes including quinone reductase [NAD(P)H dehydrogenase(quinone): NAD(P)H : (quinone acceptor) oxidoreductase, EC 1.6.99.2] is a major mechanism of whereby a large group of heterogeneous compounds prevent the toxic, mutagenic, and neoplastic effects of carcinogen. Using murine hepatoma cells(Hepalclc7 cells), quinone reductase(QR) inducers as the possible chemopreventive agents were screened from rice bran, wheat bran, soymilk residue, defatted soybean cake, defatted sesame and perilla residues. The 80% methanol extracts of defatted sesame and perilla residues induced quinone reductase significantly while the others did have little effect on the enzyme induction. Thin layer chromatography of the extracts showed that the fastest moving band(Rf=0.70) in the developing solvent of n-butanol : n-propanol : 2N ammonia(10 : 60 : 30) was responsible for the enzyme induction by the 80% methanol extracts of defatted sesame and perilla residues. Further identification of active component(s) is in progress.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.311-318
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• 2000

The purpose of this study was to determine the optimum water intaking depth for water treatment plant based on the changes of phytoplankton distributions in Unmun reservoir. Sampling was carried around of intaking tower near the Dam site at monthly intervals from February to Ocotber in 1998. Total 79 phytoplankton taxa were observed and they were classified into 4 varieties, 75 species within 51 genera. Diatoms were mainly dominated from February to July. However Rhodomonas sp. was a dominant species in August, and Microcystis ichthyblabe in September and October. Cell density of 122,800 cells/mL in October was the highest, and 415 cells/mL in May was the lowest. The pattern of vertical distribution was similar until May; however, the cell density in the epilimnion was much higher than it in the hypolimnion during the periods with the high water temperature over $20^{\circ}C$ since June. The water depths showing over 5,000 cells/mL ranged from the surface to 9m in June, surface to 6m in September, and on the only surface in October. Based on water temperature and phytoplankton vertical distribution, the depth of 6m appeared to be the optimum intaking depth far water treatment plant: 75.4 to 98.0% of phytoplankton cell densities could be avoided and the temperature over $18.3^{\circ}C$ was preserved to prevent cold water damage for rice growth at the water depth during cyanobacterial blooming period in Unmun reservoir.

• Molecules and Cells
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• v.20 no.1
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• pp.30-34
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• 2005

This study was carried out to identify a high-resolution marker for a gene conferring resistance to brown planthopper (BPH) biotype 1, using japonica type resistant lines. Bulked segregant analyses were conducted using 520 RAPD primers to identify RAPD fragments linked to the BPH resistance gene. Eleven RAPDs were shown to be polymorphic amplicons between resistant and susceptible progeny. One of these primers, OPE 18, which amplified a 923 bp band tightly linked to resistance, was converted into a sequence-tagged-site (STS) marker. The STS marker, BpE18-3, was easily detectable as a dominant band with tight linkage (3.9cM) to Bph1. It promises to be useful as a marker for assisted selection of resistant progeny in backcross breeding programs to introgress the resistance gene into elite japonica cultivars.