• Korean Journal of Soil Science and Fertilizer
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• v.35 no.2
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• pp.118-126
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• 2002

To evaluate the correlations of microbial populations with soil healthiness and crop production and establish the criteria for microbial population of soil types. We analyzed the microbial community structure of 13 soils which were different in physical and chemical properties and cultivation methods. According to the analysis of microbial population suing the dilution plate method, the large differences of the microbial population structures among soil types were shown: aerobic bacteria $2-27{\times}10^6$, fluorescent Pseudomonas $1-1,364{\times}10^5$, Gram negative bacteria $1-126{\times}10^4$, and mesophilic Bacillus $1-110{\times}10^5$. The density of Gram negative bacteria was highest on red pepper cultivating soils (sample no. 4 and 6) of Umsung and Gesan, Chungbuk, and the density of the fluorescent Pseudomonas was highest on greenhouse soil (sample no. 7) of Jinju, Kyungnam. The crop productivity of three soils was high as compared with those of other soils. It was supposed that the density of fluorescent Pseudomonas and mesophilic Bacillus were correlated with the incresed crop production. By MIDI analysis, 579 strains isolated from 13 soils composed of a variety of microbes including 102 isolates of Agrobacterium, 112 isolates of Bacillus, 32 isolates of Pseudomonas, 44 isolates of Kocuria, and 34 isolates of Pseudomonas. Among the 624 isolates of Gram negative bacteria, Pseudomonas including P. putida and p. fluorescens occupied the highest density (51%), and Stenotrophomonas maltophilia and Burkholderia cepacia also appeared at high density. From RAPD analysis, the fluorescent Pseudomonas strains isolated from 13 soil types showed a high level of strain diversities and were grouped into 2 - 14 patterns according to soil types. Many of unknown bacteria were recovered from the paddy soil, and needed to be further characterized on the molecular basis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.739-744
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• 2003

This study was carried out to investigate the antioxidative activity and to identify the active components of hot-water extract of Paeoniajaponica (PJ), which was a main ingredient of a herb mixture preparation recently established as a potent candidate of radioprotector in our laboratory. The water extract was fractionated with CHCl$_3$, EtOAc and n-BuOH. The extract and its fractions showed very low activity in hydroxyl radical scavenging test. In lipid peroxidation test, the extract, EtOAc and water fractions showed moderate inhibition with the ratio above 50%. In DPPH radical scavenging test, the extract, EtOAc and water fraction showed high activity with the ratio above 80%, especially. EtOAc fraction scavenged the radicals as much as synthetic antioxidant (BHA), even at low concentration. It is suggested that mai or partition for antioxidative activity of Paeonia japonica was EtOAc fraction. Subsequently, two active compounds (PJE021-1 and JE024-1) from EtOAc fraction were isolated by using MCI gel and silica gel column chromatography The two compounds inhibited remarkedly the $H_2O$$_2$-induced DNA damage in human peripheral blood lymphocytes, measured by single-cell gel electrophoresis (SCGE). PJE021-1 protected the cells to almost negative control level, dose-dependently. PJE024-1 exhibited a potent inhibition with the ratio of 71% at even low concentration (0.5 $\mu\textrm{g}$/$m\ell$). Finally, their chemical structures were identified as gallic acid (PJE021-1) and (＋)-catechin (PJE024-1), respectively, on the basis of the speculation of spectral and physical data.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.124-130
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• 1985

In the previous papers (Kim and Park, 1984 a, b; 1985 a), we have reported on alginic acid from Ecklonia cava and Sargassum ringgoldianum. The seasonal variation in the composition of uronic acids and their block structures of alginic acid from Myagropsis myagroides Fensholt and Sargassum horneri C. Agardh (collected from Iee Chun village on the coast of Ilgwang-myon, Yansan-gun, Kyungnam, Korea, in the period of January to December in 1982) are investigated, and their relationship between the chemical composition and some related properties are discussed in this study. One year average contents of alginic acid were $25.2\%$ in the M. myagroides and $26.5\%$ in the S. horneri, and one year average values of M/G ratios were 1.97 in the M. myagroides and 1.38 in the S. horneri. The value of M. myagroides was largest in the period of December to April, and smallest in May to June and October to November. The value of S. horneri was largest in January and smallest in March to April. The proportion of alternating, M and G block in M. myagroides were $18.4\%,\;40.4\%$, and $41.2\%$, and those in S. horneri $9.8\%,\;33.3\%$ and $56.9\%$, respectively. The higher viscosity showed the value of 45.3 cP in M. myagroides (in November), and 26.0 cP in S. horneri(in January), respectively. Furthermore, the dependence on temperature of M. myagroides alginic acid was also larger in November, that of S. horneri alginic acid in June. Ion exchange ability of M. myagroides alginic acid was highest in November and the exchange amounts were $Pb^{2+}\;4.4,\;Cu^{2+}\;1.8,\;Zn^{2+}\;2.5$ and $Co^{2+}\;2.0\;meq/g$. Na-Alg., and the ability of S. horneri alginic acid was highest in June and the amounts were $Pb^{2+}\;4.5,\;Cu^{2+}\;2.2,\;Zn^{2+}\;2.4$ and $Co^{2+}\;2.1\;meq/g.$ Na-Alg. The affinity with metallic ions appeared higher in order of $Pb^{2+}>Cu^{2+}>Zn^{2+}>Co^{2+}$, and the exchange ability assumed to relate with the block ratio of uronic acid.

• Korean Journal of Optics and Photonics
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• v.18 no.5
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• pp.351-361
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• 2007

The samples composed of a GST thin film and the protective layers of $ZnS-SiO_2$ or $Al_2O_3$ coated on c-Si substrate were prepared by using the magnetron sputtering method. Samples of three different structures were prepared, that is, i) the GST single film on c-Si substrate, ii) the GST film sandwiched by the protective $ZnS-SiO_2$ layers on c-Si substrate, and iii) the GST film sandwiched by $Al_2O_3$ protective layers on c-Si substrate. The ellipsometric constants in the temperature range from room temperature to $700^{\circ}C$ were obtained by using the in-situ ellipsometer equipped with a conventional heating chamber. The measured ellipsometric constants show strong variations versus temperature. The variation of ellipsometric constants at the temperature region higher than $300^{\circ}C$ shows different behaviors as the ambient medium is changed from in air to in vacuum or the protective layers are changed from $ZnS-SiO_2$ to $Al_2O_3$. Since the long heating time of 1-2 hours is believed to be the origin of the high temperature variation of ellipsometric constants upon the heating environment and the protective layers, a PRAM (Phase-Change Random Access Memory) recorder is introduced to reduce the heating time drastically. By using the PRAM recorder, the GST samples are heated up to $700^{\circ}C$ decomposed preventing its partial evaporation or chemical reactions with adjacent protective layers. The surface image obtained by SEM and the surface micro-roughness verified by AFM also confirmed that samples prepared by the PRAM recorder have smoother surface than the samples prepared by using the conventional heater.

• Korean journal of food and cookery science
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• v.15 no.3
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• pp.203-209
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• 1999

The effect of several hydrocolloids on the rheological behavior of wheat flour was investigated. The influence of the selected hydrocolloids (alginate, carrageenan, CMC, guar, locustbean and xanthan) on wheat flour was tested by using two different techniques; amylograph and texture analyzer. In order to have a general overview of their effects hydrocolloids were chosen from different sources implying a broad diversity of chemical structures. The hydrocolloid addition decreased the brightness(L) but increased yellowness(b). The interaction between hydrocolloid and flour produces a slight modification of the amylogram parameters, being the most clearly affected parameter breakdown, which is increased by carrageenan, guar and xanthan. Hardness and cutting force were augmented by hydrocolloid addition, while springeness was decreased except guar and locustbean. In summary, when looking for the improvement of the noodle texture, guar, locustbean are the best candidate additives due to their effects on pasting and texture properties. These hydrocolloids increase the hardness, cutting force, gumness, chew-ness, so were thought to increase the eating quality. So, each tested hydrocolloid affected in a different way the rheological properties of wheat flour, the results obtained are important for the appropriate use of these hydrocolloid as ingredients in the noodle making process.

• The Journal of Engineering Geology
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• v.21 no.1
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• pp.65-77
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• 2011

Hydrochemical and carbon isotopic (${\delta}^{13}C_{DIC}$) analyses of 11 water samples, and noble gas isotopic analyses of 8 water samples collected in the Kyeoungbuk and Kangwon areas of Korea were performed to determine their hydrochemical characteristics and to interpret the source of noble gases and $CO_2$ gas in the water. The carbonated mineral waters are weakly acidic (PH = 5.59-6.04), and electrical conductivity ranges from 302 to $864\;{\mu}S/cm$. The chemical composition of all the water samples is Ca-$HCO_3$ type. The high contents of Fe and Mn exceed the safe limits for drinking water. The ${\delta}^{13}C_{DIC}$ values of the samples range from -5.30‰ to -2.84‰, indicating that the carbon is supplied mainly from a deep-seated source and to a lesser degree from an inorganic carbonate source. The $^3He/^4He$ ratios of the samples range from $1.51{\times}10^{-6}$ to $6.45{\times}10^{-6}$. The samples plot into three groups on a $^3He/^4He$ versus $^4He/^{20}Ne$ diagram: the deep-seated field (e.g., a mantle source), the atmospheric field, and the air-mantle mixing field. A wide range of $^4He/^{20}Ne$ ratios is observed ($0.036{\times}10^{-6}$ to $1.76{\times}10^{-6}$), indicating that while radiogenic $^4He$ is dominant in these water samples, mantle-origin He is also present. The supply of $CO_2$ gas and noble gases from a deep-seated source to carbonated waters is inferred to be controlled by geological structures such as faults and geological boundaries.

• Research in Plant Disease
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• v.16 no.1
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• pp.101-105
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• 2010

This study was aimed to understand conidial disperse of the pepper anthracnose fungus Colletotrichum acutatum, elapse time for the disease development, and inoculum potentials on infected fruits. Most (99.2%) conidia of the fungus disseminated from inoculum source on the rainy day, while only 0.8% conidia dispersed on the sunny day. Among the conidia 93.3% were caught under 60 cm height at 30 cm distance; however, conidia were detected at 120 cm height at the distance. Relatively susceptible pepper fruits to anthracnose showed first visible symptoms at 4 days after infection under a mimic field condition. However, it seemed that over 10 days are required for the disease to develop on moderately resistant pepper fruits under unfavorable conditions. The number of conidia formed on a lesion was positively correlated with the lesion size ($R^{2}=0.88$). Over 10 millions of conidia were formed at a normal lesion size 1.5 cm in length. In some large coalesced lesions ca. 4cm in length produced over 100 millions of the fungal conidia. Results further confirmed that the rainfall is the key factor for the inoculum disperse of the pepper anthracnose pathogen, Colletotrichum acutatum, and a long distance dissemination is plausible according to rain and wind intensity. Consequently, rain-proof structures are ideal to avoid the disease, and removal of infected fruits and timely chemical spray are indispensible to reduce the inoculum potential in the field.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.97-107
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• 2015

Wetlands constitute a transitional zone between terrestrial and aquatic ecosystems and have unique characteristics such as frequent inundation, inflow of nutrients from terrestrial ecosystems, presence of plants adapted to grow in water, and soil that is occasionally oxygen deficient due to saturation. These characteristics and the presence of vegetation determine physical and chemical properties that affect decomposition rates of organic matter (OM). Decomposition of OM is associated with activities of various extracellular enzymes (EE) produced by bacteria and fungi. Extracellular enzymes convert macromolecules to simple compounds such as labile organic carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) that can be easily taken up by microbes and plants. Therefore, the enzymatic approach is helpful to understand the decomposition rates of OM and nutrient cycling in wetland soils. This paper reviews the physical and biogeochemical factors that regulate extracellular enzyme activities (EEa) in wetland soils, including those of ${\beta}$-glucosidase, ${\beta}$-N-acetylglucosaminidase, phosphatase, arylsulfatase, and phenol oxidase that decompose organic matter and release C, N, P, and S nutrients for microbial and plant growths. Effects of pH, water table, and particle size of OM on EEa were not significantly different among sites, whereas the influence of temperature on EEa varied depending on microbial acclimation to extreme temperatures. Addition of C, N, or P affected EEa differently depending on the nutrient state, C:N ratio, limiting factors, and types of enzymes of wetland soils. Substrate quality influenced EEa more significantly than did other factors. Also, drainage of wetland and increased temperature due to global climate change can stimulate phenol oxidase activity, and anthropogenic N deposition can enhance the hydrolytic EEa; these effects increase OM decomposition rates and emissions of $CO_2$ and $CH_4$ from wetland systems. The researches on the relationship between microbial structures and EE functions, and environmental factors controlling EEa can be helpful to manipulate wetland ecosystems for treating pollutants and to monitor wetland ecosystem services.

• The Journal of the Petrological Society of Korea
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• v.19 no.1
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• pp.31-49
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• 2010

Nearly NS-trending Fe-Ti ore bodies intermittently occur in the Hadong anorthosites, south Korea, irrespective of the rock types of the anorthosites. In order to determine their occurrence mode and deformation history, we collected the features of occurrence and geological structures in the field, petrographic features using thin sections of the principal constituent rocks, and geochemical data of ilmenites in the ore body using electron probe microanalysis. Fe-Ti ore bodies examined in this study are divided into two types: dike- and lamina-types. It is steadily supported that the dike-type has intruded into the anorthositic rocks after their emplacement and solidification. And the laminar-type is probably a result of the mylonitization and transposition of the dike-type ore bodies parallel to the shear planes, due to later strong dextral ductile shearing. In the meantime, the Fe-Ti ore bodies have experienced the stronger dextral shearing in the more northern part of the study area, i.e. Cheongryong-ri, Wolhoeng-ri, Jonghwa-ri, and Jayangri and Baekun-ri in ascending order of its strength, together with the less content of $TiO_2$. All ilmenites of the ore bodies have very similar chemical composition, as pure ilmenite of 52~55 wt.% in $TiO_2$ content, irrespective of the occurrence mode and degree of later ductile shearing of the ore bodies. And they didn't experience to exsolve into magnetite. The structural data indicate that the Hadong anorthosites have deformed by NNE-trending folding, intrusion of the Fe-Ti ore bodies, NNW~NNE-trending dextral ductile shearing, NW~NNW-trending sinistral semi-brittle shearing, and intrusion of NNE~NE-trending mafic dykes in descending order of chronology after the formation of foliation of the anorthositic rocks. The foliation is interpreted as a result of the accumulation of crystals that settle out from the magma by the action of gravity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.29-36
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• 1985

In the previous papers (Kim and Park, 1984 a, b), we have reported on alginic acid from Ecklonia cava. The seasonal and portional variation in the composition of uronic acids and their block structures of alginic acid from Sargassum ringgoldianum (collected from Ichon-ri at the coast of Ilgwang-myon, Yangsan-gun, Kyongnam, Korea, in the period of January to December in 1982) are investigated, and their relationship between the chemical composition and some rotated properties is discussed in this study. The results are as follows: 1. One year average contents of alginic acid were $21.4\%$ in the stipe and $19.7\%$ in the frond, one-year average values of M/G ratios were 2.38 in the frond and 1.85 in the stipe. The value of frond was largest in the period of Jauuary to April and smallest in May and October to December. The value of stipe was largest January to April and smallest in May. In general, the proportions of M block in the both of frond and stipe were higher than those of G block. 2. The viscosity of frond alginic acid showed higher values of 31.1 cP in November, and lower (below 7.0 cP) in the stipe alginic acid. Furthermore, the dependence on temperature of frond alginic acid was also larger in November and others were lower. Ion exchange ability of frond alginic acid was highest in July and the exchange amounts were $Pb^{2+}\;5.2,\;Cu^{2+}\;3.1,\;Zn^{2+}\;1.7,\;Co^{2+}\;1.5$ meq/g, Na-Alg., and the ability of stipe alginic acid was highest in May and the amounts were $Pb^{2+}\;4.6,\;Cu^{2+}\;3.3,\;Zn^{2+}\;2.5,\;Co^{2+}\;1.4$ meq/g. Na-Alg.. The affinity with metallic ions appeared higher in order of $Pb^{2+}>Cu^{2+}>Zn^{2+}>Co^{2+}$, and the exchange ability assumed to relate with the block ratio of uronic acid.