• Korean Journal of Microbiology
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• v.52 no.2
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• pp.175-182
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• 2016

In this study, we isolated aromatic compounds (lignin polymers) utilizing bacteria in humus layer of oak forest and investigated phylogenetic characteristics and correlation with major bacterial populations in the humus layer by pyrosequencing. Forty-two isolates using aromatic compounds such as p-anisic acid, benzoic acid, ferulic acid and p-coumaric acid were isolated and phylogentic analyses based on 16S rRNA gene sequences showed that the isolates belonged to the genus Rhizobium, Sphingomonas, Burkhorlderia, and Pseudomonas. Among these, Burkhorlderia species which belong to Betaproteobacteria class occupied 83% among the isolates. The bacterial populations in humus layer of oak forest were characterized by next generation pyrosequencing based on 16S rRNA gene sequences. The humus sample produced 7,862 reads, 1,821 OTUs and 6.76 variability index with 97% of significance level, respectively. Bacterial populations consist of 22 phyla and Betaproteobacteria were the major phylum consisting of 15 genera including Burkholderia, Polaromonas, Ralstoria, Zoogloea, and Variovorax. Approximately fifty percentage of them was Burkholderia. Burkholderia as the majority of population in the humus was considered to play a role in degrading lignin in humus layer of oak forest.

• Journal of Ecology and Environment
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• v.41 no.6
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• pp.152-164
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• 2017

Background: Natural regeneration of seedlings as well as saplings of Korean fir has been significantly impacted by the browsing from the early stages of their development, potentially, by roe deer for the last two to three decades at the study site since late 1980s. This study was carried out to investigate current status of the disturbance in the seedling development of Korean fir (Abies koreana) on Mt. Hallasan, Jeju Island, Korea. Methods: Field survey was carried out during June and August in 2016 to measure the characteristics of study site and understory vegetation by applying systematic sampling to 125 plots of $5m{\times}5m$ quadrat located on eastern slope of the mountain. Correlation and regression analyses were applied to the variables quantified from the data sets using the SAS software. Results: No saplings with their diameters at breast heights smaller than 5.0 cm were found at the study site indicating the serious disturbance in the natural regeneration of Korean fir at the study site. No seedlings with their heights taller than 36.0 cm were found at the study site indicating even more serious disturbance during earlier stage of the natural regeneration of Korean fir at the study site. A total of 616 individuals of the seedlings of Korean fir were found at 54 out of 125 sampling plots. One hundred thirty-eight seedlings (22.4%) out of 616 individual seedlings have the vestiges for being grazed, potentially, by roe deer. Conclusions: Due considerations should be given to the effects of browsing of the seedlings by roe deer to promote the natural regeneration of Korean fir, ultimately to restore Korean fir. It is needed for the managers of the forest to install fences around the forest area. Exclosure experiments as well as enclosure experiments of different densities of browsing should be carried out. In addition, treatment with different densities of Jeju dwarf bamboo should also be included in the experiment on Mt. Hallasan National Park, Jeju Island, Korea.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.51-58
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• 2014

Genetic diversity and genetic structures were estimated in seven natural populations of Phellodendron amurense Rupr in South Korea using ISSR markers. The average of polymorphic loci per primer and the proportion of polymorphic loci per population were 4.5 and 78.8% respectively with total 27 polymorphic loci from 6 ISSR primers. The Shannon's diversity index(I) was 0.421 and the expected heterozygosity($H_e$) was 0.285, which was similar to the heterozygosity (hs =0.287) inferred by Bayesian method. In AMOVA, 7.6% of total genetic variation in the populations was resulted from the genetic difference among populations and the other 92.4% was resulted from the difference among individuals within populations. Genetic differentiation(${\theta}^{II}$) and inbreeding coefficient(f) for total population were estimated to be 0.066 and 0.479 by Bayesian method respectively. In Bayesian clustering analysis, seven populations were assigned into three groups. This result was similar to the results of genetic relationships by UPGMA and PCA. The first group included Hwachoen, Gapyeong, Bongpyeong and Yongpyeong population, and the second included two populations in Sancheong region. Muju population was discretely assigned into the third group in spite of the geographically short distance from the Sancheong region. There was no significant correlation between genetic relationship and geographic distribution among populations in Mantel's test. For conservation of the phellodendron trees, it would be effective to consider the findings resulted from this study with ecological traits and life histories of this species.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.83-89
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• 2000

Bentonite has been considered as a liner material to restrict the release of hazardous heavy metals from the landfill. The adsorption of copper onto a domestic bentonite was studied to provide the adsorption isotherm and the effect of solution chemistry and temperature. The copper adsorption was fitted well to a Freundlich isotherm, in which Freundlich constants and correlation coefficient were calculated to be $K_F=1.18$, n=1.65, and $r^2=0.97$, respectively. The distribution coefficients ($K_d$) for the adsorption of copper decreased with increasing initial copper concentration. The $K_d$ increased with increasing the pH of solution, and drastically increased at pH > 5.3 because of precipitation of most copper species. As the ion strength of $Na^+$ in solution increased the $K_d$ decreased, while it increased with increasing the concentration of $SO_4{^{2-}}$ in solution. An increase in the temperature of experimental solution decreased the $K_d$ values.

• Parasites, Hosts and Diseases
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• v.29 no.4
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• pp.325-338
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• 1991

The present study was undertaken to determine the endemicity of trematode infections in Yongyang County, Kyungpook Province, Korea. One hundred and seventy-seven out of 955 residents examined were found to be infected with one or more kinds of helminthes. The prevalence rate was 18.5%. Among them, 70 were found to be infected with Clenorchis sinensis, 74 with Meta-gonimus sp. and 2:l with both flukes. The eggs of Fasciolidae were demonstrated from two specimens. The prevalence rate of clonorchiasis in males was 12.6%, while that in females was 3.6% (p<0.05). The prevalence of metagonimiasis in males was 12.0% and was also significantly higher than 6.1% in females (p<0.05). The intensity of both infections was significantly heavier in males than in females. The prevalence of both nukes was higher in residents of oyer 30 years of age than in those below that age. No correlation was found between the intensity and the age group. Among eight species of the fresh-water fish collected at the Panbyon River, Zacco temmincki was found to be the most frequently and heavily infested with metacercariae of Metagonimus sp., and Gnathopogon asromaculatus alone was found to be infested with metacercariae of Clonorchis sinensis. The present results suggest that Yongyang area still remains endemic with Clonorchis sinensis and Metagonimus sp. infection.

• The Korean Journal of Nuclear Medicine Technology
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• v.21 no.1
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• pp.23-28
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• 2017

Purpose Recently, there has been increasing demands for clinical departments at Asan Medical center in Seoul. They want to see the results of lab tests about blood samples as soon as possible and to be reported to them on the day. As the main contents of the survey, we explained the goodness of Asan medical center's in vitro and the points to be improved. Based on this, it became an opportunity to create a positive image of In vitro laboratory. In addition, we could identify their specific requirements through the surveys. Materials and Methods In September 2016, a total of 14 questionnaire surveys were conducted for 49 clinical departments and outpatient nurses at Asan Medical center in Seoul. The survey consists of description questions to be able to express the intention of the individual and the questions made on the Likert 4 point scale. The main contents of 14 questions are composed of goodness of In Vitro laboratory and points to be improved. Results 62% answered that the best service in In Vitro laboratory was "good accuracy and reproducibility". On the other hand, as an inconvenience when requesting blood tests, 73% pointed out that "the result report time was long", which was recognized as a part to be improved. There are many contents that "The result of all tests is reported within 2 hours" on the day of the examination. In the question - 'Are there some examination results which do not coincide well with clinical observations?', 55 of 56 people answered "no". Above all, the majority answered that waiting for re-examination results is too long. This problem must be causing discomfort to the patients. Conclusion In order to improve these problems, the first thing is to increase the number of blood tests by using the current personnel, equipments and reagents to the fullest by item in Asan Medical Center's Nuclear medicine in vitro part. Secondly, in case of re-examinations, we use the "AMIS message" to show other clinical departments the reporting time. This methode improves the efficiency of work with nurses and increases satisfaction of custom service. Thirdly, the correlation was evaluated by selecting the test species that can be carried out by the shortening method. Currently, C-peptide and insulin are implemented in the reaction process to shorten 2 hours into 1 hour. Finally, we are considering purchasing new equipments for quick test results.

• The Journal of the Korean Society for Microbiology
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• v.22 no.3
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• pp.233-240
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• 1987

The amniotic fluid provides a medium in which the fetus can readily move, cushions him against possible injury and helps him maintain an even temperature. Besides above mentioned functions, investigators reported that human amniotic fluid contains host-resistance factors which prevent bacteria from producing infectious disease and this activity shows difference among human racial groups or bacterial genera, species and strains. 40 amniotic fluid specimens from Korean women in their second and third trimesters of pregnancy were examined for inhibiting the growth of Escherichia coli. And various factors which might affect bacterial growth inhibiting activity such as pH, initial inoculum size, concentration of amniotic fluid, and heat resistance, were also tested using a strongly inhibitory amniotic fluid specimen. Finally plate diffusion tests were carried out using other strongly inhibitory amniotic fluid. The following results were obtained: 1. Of the 40 fluid samples examined, 18 specimens(45%) had inhibitory activity and samples from women in their second trimester of pregnanancy showed non-inhibitory activity(2 specimens). 2. The pH of the fluids varied between 7.43 and 8.33. There was no correlation between pH and inhibitory activity. 3. No. 19 amniotic fluid showed bacteriostatic activity after 24 hours incubation when an inoculum of $10^2$ organisms per milliliter was used, but non-inhibitory with an inoculum of $10^3$ and $10^4$ bacteria per milliliter. 4. The content of amniotic fluid in culture media influenced E. coli growth. At 90 percent, E. coli was inhibited growth but at 10 percent and 50 percent. 5. Inhibitory activity of No. 19 amniotic fluid was retained after heating to $50^{\circ}C$ for 30 minutes or 100^{\circ}C$ for 30 minutes. 6. Plate diffusion tests with No. 27 amniotic fluid showed that 0.7ml amniotic fluid gave clear zone of growth inhibition around the central well but 0.2ml and 0.1ml amniotic fluids were not.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.56-62
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• 1998

Seasonal variations of eelgrass and epiphytic algae in eelgrass beds in Kwangyang Bay were studied from January 1994 to December 1994. A peak of the shoot length and standing crop of eelgrass occurred in summer, but low values were observed in fall and winter. The dominant species of epiphytic algae were Callophyllis rhynchocarpa and Champia sp. In spring and summer, while Polysiphonia japonica and Lomentaria hakodatensis in fall and winter. In contrast to the eelgrass, the standing crop of epiphytic algae showed a minimum in summer. There was a gradual increase in the standing crop of epiphytic algae during fall, and a peak of standing crop occurred in winter. Epiphytic algae accounted for approximately $15\~20\%$ of total plant standing crops of the eelgrass meadows. Correlation analysis with environmental factors indicated that temperature influences on both the standing crop of eelgrass and epiphytic algae. There was a positive relationship between the standing crop of eelgrass and temperature, while there was a reverse relationship between that of epiphytic algae and temperature.

• Korean Journal of Food Science and Technology
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• v.51 no.5
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• pp.411-419
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• 2019

A comprehensive comparison of fatty acid and metabolite profiles in 8 species of perilla seeds harvested from Korea and China was carried out to understand the correlation between cultivation conditions and the quality of perilla seeds. Metabolomic studies revealed that the perilla seeds were distinct from each other, based on the partial least squares -discriminant analysis (PLS-DA) score plots; 23 compounds including metabolites, fatty acids, and phytosterols that predominantly contributed to this interspecies difference were identified. Changes in the growth environment affected these compounds. In particular, phenolic compounds were affected by rainfall and temperature. Moreover, temperature and altitude showed negative and positive correlations, respectively, to oleic acid. Although more studies on the effect of various environmental factors on cultivation of perilla plants as well as their seeds are needed, the present results provide information that would be useful in identifying perilla seeds produced in specific regions and in the cultivation of good quality perilla.

• Journal of Life Science
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• v.31 no.10
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• pp.922-928
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• 2021

To profile the microbial compositions of Korean traditional fermented paste made from whole soybeans, Doenjang and Cheonggukjang, and compare their taxonomic differences, we analyzed the V3-V4 region of 16S rRNA of naturally fermented foods by using next generation sequencing. α-Diversity results showed that values indicating bacterial community abundances (OTUs) and richness (ACE, Chao1) were statistically significant (p=0.0001) in Doenjang and Cheonggukjang. Firmicutes was the most common phylum in both groups, representing 97.02% and 99.67% in the Doenjang and Cheonggukjang groups, respectively. Bacillus was the most dominant genus, accounting for 71.70% and 59.87% in both groups. Linear discriminant (LDA) effect size (LEfSe) analysis was performed to reveal the significant ranking of abundant taxa in different fermented foods. A size-effect threshold of 2.0 on the logarithmic LDA score was used for discriminative functional biomarkers. On the species level, Bacillus subtilis, Tetragenococcus halophilus, and Clostridium arbusti were significantly more abundant in Doenjang than in Cheonggukjang, whereas Bacillus thermoamylovorans, Enterococcus faecium, and Lactobacillus sakei were significantly more abundant in Cheonggukjang than in Doenjang. Permutational multivariate analysis of variance (PERMANOVA) showed that the statistical difference in microbial clusters between the two groups was significant at the confidence level of p=0.001. This research could be used as basic research to identify the correlation between the biochemical characteristics of Korean fermented foods and the distribution of microbial communities.