• KSBB Journal
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• v.23 no.5
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• pp.398-402
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• 2008

Cyanobacteria havebeen identified as one of the most promising group producing novel biochemically active natural products. Cyanobacteria are a very old group of prokaryotic organisms that produce very diverse secondary metabolites, especially non-ribosomal peptide and polyketide structures. Though many useful natural products have been identified in cyanobacterial biomass, cyanobacteria produce also extracellular proteins related with NRPS/PKS. Detection of unknown secondary metabolites in medium was carried in the present study by a screening of 98 cyanobacterial strains. A degenerated PCR technique as molecular approaches was used for general screening of NRPS/PKS gene in cyanobacteria. A putative PKS gene was detected by DKF/DKR primer in 38 strains (38.8%) and PCR amplicons resulted from a presence of NRPS gene were showed by MTF2/MTR2 primer in 30 strains (30.6%) and by A3/A7 primer in 26 strains (26.5%). HPLC analysis for a detection of natural products was performed in extracts from medium in which cyanobacteria containing putative PKS or NRPS were cultivated. CBT57, CBT62, CBT590 and CBT632 strains were screened for a production of extracellular natural products. 5 pure substances were detected from medium of these cyanobacteria.

• Proceedings of the KSRS Conference
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• v.1
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• pp.324-327
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• 2006

This research is about the optical characteristic of red tide which is collected from Nam-Hae for basic research of red tide remote sensing technique development. 21 kinds of red tide organisms are cultivated to investigate optical characteristic of them on the level of laboratory, and chlorophyll specific absorption coefficient($a^*$) and backscattering coefficient($b_b^*$) are estimated by using spectrophotometer. Absorption spectrums according to species are appeared diversely from 0.005 to 0.06 (mg/ $m^2$), and the shapes of spectrums are also different. The range of $b_b^*$ are appeared $10^{-2}{\sim}10^{-4}$ mg/ $m^2$, which have around 100 times differences between species, and the shape of spectrum also have significant difference between species. These results are able to use as an input data of inverse model from ocean color.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.3
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• pp.115-132
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• 1996

The purpose of this study is to estimate the soil loss amount with Geographic Information System according to the land use change of Buju mountain area in Mokpo city. To estimate the soil loss, Universal Soil Loss Equation which is the most proper technique to predict soil loss in this site condition is adopted and IDRISI, a raster GIS software, is used. GIS application with USLE is very efficient to estimate soil loss accurately and fastly. In order to decide value and to find application method of USLE factors, we used existing rainfall erosion index, soil erodibility analysis, slope length, slope steepness, vegetation management and practices, which are rated by GIS through the analysis of various studies related USLE. The result of this study was compared with the previous other researches to verify our method of constructing numerical data of USLE's factors. The result of verification of our way showed significance for the soil loss in forest area. But the result of verification for the soil loss in forest area. But the result of verification for the soil loss of cultivated area showed some errors. It seems that this result was due to local variation of topographical map.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.901-905
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• 2014

The efficacy of ozone micro-bubble water (OMBW) in reducing microbial populations on alfalfa seeds was investigated in this study. We observed the surface of alfalfa seeds using microscopy and found that many cracks and crevices existing on the surface could harbor pathogens. Alfalfa seeds were treated with tap water (TW), micro-bubble water (MBW), ozone water (OW), ozone micro-bubble water (OMBW), and chlorine water (CL) for 5 min, and total microbial population, E. coli and Salmonella spp. colonies were determined. Also, the sterilized seeds were germinated and cultivated for 5 d after sowing to investigate the percentage of germination and the growth of alfalfa sprouts. The treatments with OMBW and CL were most effective in reducing total microbial populations and E. coli was eliminated by OW, OMBW, and CL treatments. CL treatment reduced the percentage of germination and fresh weight of alfalfa sprouts, but OMBW did not cause any negative effects on the germination and growth of alfalfa sprouts. These results indicate that OMBW can be used as an effective sanitizer for eliminating seed-borne pathogens without detrimental effects on seed viability.

• KSBB Journal
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• v.9 no.5
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• pp.499-505
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• 1994

Bacillus macerans cyclodextrin glucanotransferase(EC 2.4.1.19: 1, 4-${\alpha}$-D(1, 4-${\alpha}$-glucano)-transferase, CGTase) was purified by the technique of starch adsorption and DEAE-cellulose column chromatography. The molecular weight of the enzyme was 67,000, consisting of a subunit. The enzyme converted starch into ${\alpha}$-, ${\beta}$-, and ${\gamma}$-CD in the relative amounts of 1:1.68:0.32, respectively. In the early reaction period, maltohexose was formed mainly by the coupling reaction of ${\alpha}$-CD with D-glucose and then other oligosaccharides. Maltotetrose was formed mainly from ${\alpha}$-CD in the initial stage of hydrolysis of the enzyme and then small amount of other oligosaccharides. Maltotriose was a good substrate for the enzyme and maltosyl or D-glucopyranosyl group can be transfered from this sugar. In this work, D-glutosyl transfer was premiered.

• KSBB Journal
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• v.18 no.6
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• pp.461-465
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• 2003

Five denitrifying bacteria, which were identified as Pseudomonas sp., were isolated by the enrichment culture technique. The most effective denitrifying bacterium was named as Pseudomonas DWS, which was cultivated at anoxic condition. The optimal growth temperature and pH were 30$^{\circ}C$ and 7-8, respectively. Cell growth almost revealed a stationary phase at 18 hours after cultivation and nitrate was degrade 99.9％ during this period. Therefore, it is suggested that Pseudomonas DWS could be effectively used for the biological treatment of wastewater containing nitrogen compounds.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1509-1513
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• 2009

The research of applying reinforced retaining wall due to support the land pressure that given from train's load has been accomplished actively in domestic area. After the retaining wall has been installed, the collapse or partial destruction that generated by effect of train's vibration and repetitive load of train may be induced. Accordingly in the period of using this, the sufficient durability should be guaranteed and years of durability are one hundred and as these are longer than road structure's, the technique that introduced to wall and monitor the long-term strain is necessary. In this paper, the optical fibre is induced vertically to the reinforced retaining wall and after the subsistence of optical fibre is confirmed, the early strain that applied to optical fibre after insertion is monitored. Before and after the concrete placing, damage feasibility of optical fibre is measured by using OTDR(Optical Time Domain Reflectometer) and after concrete is cultivated, the early strain induced to optical fibre is measured by application of BOCDA (Brillouin Correlation Domain Analysis) system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.215-221
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• 2023

If the C++ programming class, an object-oriented language capable of modeling similar to the real world, is developed as a curriculum that introduces the flipped learning model, students' active problem-solving skills can be cultivated. In this subject development case, it is significant that the flipped learning technique was applied to the programming class and was effective in improving students' active problem-solving skills. First, the lectures in the 4th session were divided into Pre-Class, In-Class, and Post-Class, and the class was conducted in a way that suggested class goals suitable for the subject and formed a team to discuss. At the end of the lecture, a follow-up survey was conducted to check whether the learners learned effectively.

• Journal of Korean Society of Water and Wastewater
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• v.38 no.2
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• pp.109-117
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• 2024

In this study, various pre-treatment methods were evaluated for microalgae separation. These methods aimed to facilitate safe, rapid, and cost-effective online imaging for real-time observation and cell counting. As pre-treatment techniques, heating, chemical hydrolysis, heating combined with chemical hydrolysis, and sonication were employed. The effectiveness of these methods was evaluated in the context of online imaging quality through experimentation on cultivated microalgae (Chlorella vulgaris and Scenedesmus quadricauda). The chemical treatment method was found to be inappropriate for improving image acquisition. The heating pre-treatment method exhibited a drawback of prolonged cell dispersion time. Additionally, the heating combined with chemical hydrolysis method was confirmed to have the lowest dispersion effect for Chlorella vulgaris. Conversely, ultrasonication emerged as a promising technique for microalgae separation in terms of repeatability and reproducibility. This study suggests the potential for selecting optimal pre-treatment methods to effectively operate real-time online monitoring devices, paving the way for future research and applications in microalgae cultivation and imaging.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.122-126
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• 1998

This experiment was conducted to verify the responses of major crop species to saline stress.To determine the saline tolerance of crop species, sevral crop species were cultivated under sand-culture system using Hoagland's nutrient solution whit 200mM NaCl. The crop species showing saline tolerance were cotton(Gossypium indicum), maize(Zea mays), barely(Hordeum vulgare), and wheat(Triticum aestivum) but perilla (Perilla frutescens) and leguminous crops, mung bean(Phaseolus radiatus), azuki bean(Phaseolus angularis) and soy bean(Glycin max) showed very por tolerance. One the typical symptom was the darkening of leaf color due to increase of chlorophyll concentration.Among of the plant families, Fabaceae was the most susceptible but crop species belonging to Poaceae were more proper for cultivating on reclaimed tidal land in the course of desalinazation. It was suggrsted that the crop species belonging to Fabaceae, a sensitive family to soil salinity, must be cultivated when the soil salinity decreased below 10ds/m. To know the critical salinity level for crop growth,salinity of saline soil collected from reclaimed tidal land was adjusted from 10.0ds/m tp41.7ds/m with tap water. It was suggested that the ECs of the soil in which the plant height of each crop spicies was reduced to 50% of control plant were 22.6 and 21.7 ds/m in rice, barley, corn, mung bean, and soy bean,respectively.