• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.97-104
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• 2020

The present study conducted mock-up tests under the simulated sewage environments to examine the practical significance and limitation of coating materials that were previously developed on the basis of the bacterial glycocalix as a protection of concrete structures exposed to microbiological and sulphate attacks. The variations of the compressive strength and mass of the concrete due to the sulphate attack were measured using cylinder specimens. The bacteria growth and glycocalix formulation were calculated from the samples extracted from the sewage pipes. The next generation sequencing analysis was also conducted for environmental damage assessment due to the use of Rhodobacter capsulatus in the simulated sewage environments. The mock-up tests revealed that the developed coating materials have a good potential in resisting the sulphate attack, indicating no reduction on compressive strength and mass of the coated concrete under the sewage environment. At the age of 91 days, the concentrations of viable bacteria and glycocalix measured from the hardened coating materials were 1.4×10⁴cell/mL and 67.5mg/㎤, respectively. Moreover, harmful strains were not observed in the sewage water including glycocalix-coated concrete pipes. This implies that Rhodobacter capsulatus used in the coating materials does not influence negatively the microorganism cluster in the sewage environments.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.547-557
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• 2010

This paper presents a study on the development of next generation smart concrete in an eco-friendly manner using micro-biologically induced calcite precipitation (MICP) via microbial biomineralization. It seems that currently, the reformation and functional improvement of concrete using MICP can be achieved using Sporosarcina pasteurii, which is a representative microorganism that produces calcite precipitation. Based on previous studies on MICP the biochemical tests and crystallinity evaluation of cement using sporoasrcina pasteurii and four additional micro-organisms from the concrete structures as identified by 16S rDNA sequence analysis were conducted. Also by applying the Sporosarcina pasteurii and separated four effective micro-organisms from the concrete structures to mortar, the compressive strength improvement by varying curing conditions, repair of crack were examined, and plans for future study were suggested. The effect of the application of effective micro-organisms can lead to the development of a new material that will contribute to resolution of environmental problems and facilitate repair work, and this can also serve as a new research theme in the future. In addition, the importance of this study is to use micro-organism, which is found common in concrete structures, this new microbial is not only environmentally safe but also persists in the natural environment for an extended period of time. Therefore, it seems to have a great potential to became a new environmentally low-burdened functional material.

• Korean Journal of Food Science and Technology
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• v.52 no.5
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• pp.529-537
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• 2020

This study was carried out to confirm changes in the microbial community and physicochemical characteristics of Korean traditional Makgeolli during fermentation by yeast as a fermentation starter. We demonstrate that the microbial community during fermentation affects the quality of Makgeolli. At the species level, Pediococcus pentosaceus, Weissella confusa, Pantoea vagans, and Lactobacillus graminis were dominant on fermentation mix, after 1-2 days, in the control group without yeast treatment. Acid production in the control group was higher than that in the yeast-treated group. P. pentosaceus was dominant throughout the fermentation process, and the proportion of P. vagans remarkably decreased following yeast addition. Considering quality characteristics, the alcohol content rapidly increased after yeast addition, and the lactic acid content was lower in the yeast-treated group than in the control. These results suggest that the rapid increase in alcohol at the start of fermentation inhibits the growth of lactic acid-producing bacteria. The addition of yeast may contribute to the reduction in the high amount of lactic acid, which can be one of the causes of changes in Makgeolli quality.

• Journal of Life Science
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• v.26 no.9
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• pp.1097-1104
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• 2016

With the development of next generation sequencing (NGS), large numbers of transcriptional molecules have been discovered. Most transcripts are non -coding RNAs (ncRNAs). Among them, long non-coding RNAs (lncRNAs) with more than 200 nucleotides represent functional RNA molecule that will not be translated into protein. In plants, lncRNAs are transcribed by RNA polymerase II (Pol II) or Pol III, Pol VI and Pol V. After transcription of these lncRNAs, more RNA processing mechanisms such as splicing and polyadenylation occurs. The expression of plant lncRNAs is very low and is tissue specific. However, these lncRNAs are strongly induced by specific external stimuli. Because different external stimuli including environmental stresses induce a large number of plant lncRNAs, these lncRNAs have been gradually considered as new regulatory factors of various biological and development processes such as epigenetic repression, chromatin modification, target mimicry, photomorphogenesis, protein relocalization, environmental stress response, pathogen infection in plants. Moreover, some lncRNAs act as precursor of short RNAs. Although a large number of lncRNAs have been predicted and identified in plants, our current understanding of the biological function of these lncRNAs is still limited and their detailed regulatory mechanisms should be elucidated continuously. Here, we reviewed the biogenesis and regulation mechanisms of lncRNAs and summarized the molecular functions unraveled in plants.

• Korean Journal of Ecology and Environment
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• v.56 no.1
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• pp.36-44
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• 2023

Environmental DNA (eDNA) can exist in both intracellular and extracellular forms in natural ecosystems. When targeting harmful cyanobacteria, extracellular eDNA indicates the presence of traces of cyanobacteria, while intracellular eDNA indicates the potential for cyanobacteria to occur. However, identifying the "actual" potential for harmful cyanobacteria to occur is difficult using the existing sediment eDNA analysis method, which uses silica beads and cannot distinguish between these two forms of eDNA. This study analyzes the applicability of a density gradient centrifugation method (Ludox method) that can selectively analyze intracellular eDNA in sediment to overcome the limitations of conventional sediment eDNA analysis. PCR was used to amplify the extracted eDNA based on the two different methods, and the relative amount of gene amplification was compared using electrophoresis and Image J application. While the conventional bead beating method uses sediment as it is to extract eDNA, it is unknown whether the mic gene amplified from eDNA exists in the cyanobacterial cell or only outside of the cell. However, since the Ludox method concentrates the intracellular eDNA of the sediment through filtration and density gradient, only the mic gene present in the cyanobacteria cells could be amplified. Furthermore, the bead beating method can analyze up to 1 g of sediment at a time, whereas the Ludox method can analyze 5 g to 30 g at a time. This gram of sediments makes it possible to search for even a small amount of mic gene that cannot be searched by conventional bead beating method. In this study, the Ludox method secured sufficient intracellular gene concentration and clearly distinguished intracellular and extracellular eDNA, enabling more accurate and detailed potential analysis. By using the Ludox method for environmental RNA expression and next-generation sequencing (NGS) of harmful cyanobacteria in the sediment, it will be possible to analyze the potential more realistically.

• Journal of Life Science
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• v.33 no.7
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• pp.565-573
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• 2023

In light of the complex interactions between the host animal and its resident gut microbiomes, studies of these microbial communities as a means to improve cattle production are important. This study was conducted to analyze the intestinal microorganisms of Holstein (HT) and Jersey (JS), raised in Korea and to clarify the differences in microbial structures according to cattle species through next-generation sequencing. The alpha-diversity analysis revealed that most species richness and diversity indices were significantly higher in JS than in HT whereas phylogenetic diversity, which is the sum of taxonomic distances, is not significant. Microbial composition analysis showed that the intestinal microbial community structure of the two groups differed. In the both groups, a significant correlation was observed among the distribution of several microbes at the family level. In particular, a highly significant correlation (p<0.0001) among a variety of microbial distributions was found in JS. Beta-diversity analyis was to performed to statistically verify whether a difference exists in the intestinal microbial community structure of the two groups. Principal coordinate analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering analysis showed separation between the HT and JS clusters. Meanwhile, permutational multivariate analysis of variance (PERMANOVA) revealed that their microbial structures are significantly different (p<0.0001). LEfSe biomarker analysis was performed to discover the differenc microbial features between the two groups. We found that several microbes, such as Firmicutes, Bacilli, Moraxellaceae and Pseudomonadales account for most of the difference in intestinal microbial community structure between the two groups.

• Journal of Life Science
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• v.34 no.4
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• pp.254-263
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• 2024

Korean jang is a food made using fermented soybeans, and the typical products include gochujang (GO), doenjang (DO), cheonggukjang (CH), and ganjang (GA). In this study, 16S rRNA metagenome analysis was performed on a total of 200 types of GO, DO, CH, and GA using next-generation sequencing to analyze the microbial community of fermented soybean foods and compare taxonomic (biomarker) differences. Alpha diversity analysis showed that in the CHAO index, the species richness index tended to be significantly higher compared to the DO and GA groups (p<0.001). The results of the microbial distribution analysis of the GO, DO, CH, and GA products showed that at the order level, Bacillales was the most abundant in the GO, DO, and CH groups, but Lactobacillales was most abundant in the GA group. Linear discriminant analysis effect (LEfSe) analysis was used to identify biomarkers at the family and species levels. Leuconostocaceae, Thermoactinomycetaceae, Bacillaceae, and Enterococcaceae appeared as biomarkers at the family level, and Bacillus subtilis, Kroppenstedtia sanguinis, Bacillus licheniformis, and Tetragenococcus halophilus appeared at the species level. Permutational multivariate analysis of variance (PERMANOVA) analysis showed that there was a significant difference in the microbial community structure of the GO, DO, CH, and GA groups (p=0.001), and the microbial community structure of the GA group showed the greatest difference. This study clarified the correlation between the characteristics of Korean fermented foods and microbial community distribution, enhancing knowledge of microorganisms participating in the fermentation process. These results could be leveraged to improve the quality of fermented soybean foods.

• Tuberculosis and Respiratory Diseases
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• v.59 no.3
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• pp.250-256
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• 2005

Background : Fluoroquinolone drugs are an important anti-tuberculous agent for the treatment of multi-drug resistant tuberculosis. However, many drugs belonging to the fluoroquinolones have different cross resistance to each other. Methods : Sixty-three ofloxacin (OFX) resistant and 10 pan-susceptible M. tuberculosis isolates were selected, and compared for their cross resistance using a proportion method on Lowenstein-Jensen media, containing ofloxacin (OFX), ciprofloxacin (CIP), levofloxacin (LVX), moxifloxacin (MXF), gatifloxacin (GAT) and sparfloxacin (SPX), at concentrations ranging from 0.5 to $3{\mu}g/ml$. DNA extracted from the isolates was directly sequenced after amplifying from the gyrA and gyrB genes. Results : The 63 OFX resistant M. tuberculosis isolates showed complete cross resistance to CIP, but only 90.5, 44.4, 36.5 and 46.0% to LVX, MXF, GAT, and to SPX, respectively. Fifty-one of the isolates (81.0%) had point mutations in codons 88, 90, 91 and 94 in gyrA, which are known to be correlated with OFX resistance. The Gly88Ala, Ala90Valand Asp94Ala mutations in gyrA showed a tendency to be susceptible to MXF, GAT and SPX. Only 4 isolates had mutations in the gyrB gene, which did not affect the OFX resistance. Conclusion : About 60% of the OFX resistant M. tuberculosis isolates were susceptible to GAT, SPX and MXF. These fluoroquinolones may be useful in the treatment of TB patients showing OFX resistance.

• Korean Journal of Microbiology
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• v.53 no.1
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• pp.39-48
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• 2017

In order to evaluate the diversity of microbial population of Korean traditional Deonjang and Gochujang produced in Jeju, Jeonnam, and Jeonbuk province area, microbial communities were analyzed using next generation sequencing. In this result, the dominant bacteria of Deonjang in three area were Bacillus amyloliquefaciens, Tetragenococcus halophilus, and Bacillus was major dominant bacteria in Jeonnam (43.16%) and Jeonbuk (64.54%) area. But in Jeju area, Bacillus was 0.22%, which was significantly different from the other two. Equally, the dominant fungi of Deonjang in 3 area were Candida versatilis. Common fungus in Jeonnam and Jeonbuk area was Candida sp., respectively, 64.22% and 33.68% and Micor sp. was a common fungus in Jeonnam (15.66%) and Jeonbuk area (36.73%). But in Jeju area, Candida sp. and Zygosaccharomyces rouxii were dominant than mold. Bacillus subtilis, Bacillus licheniformis, and B. amyloliquenfaciens were the preminant bacteria in the traditional Gochujang in three regions. But there were no common dominant fungi in the 3 regions. Aspergillus sp. and Rhizopus sp. prevailed in Jeju and Jeonnam region, and Zygosaccharomycess rouxii predominanted in Jeonbuk area. These results suggested that the difference in the samples collected for the study were classified into similar groups according to the characteristics of each sample rather than regional characteristics.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.268-273
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• 2019

The intestinal microbiomes vary according to the factors such environment, age and diet. The purpose of this study was to compare the gut microbial diversity between Korean infants receiving breast-fed milk and formula-fed milk. We analyzed microbial communities in stool samples collected from 80 Korean infants using next generation sequencing. Phylum level analysis revealed that microbial communities in both breast-fed infants group (BIG) was dominated by Actinobacteria ($74.22{\pm}3.48%$). Interestingly, the phylum Actinobacteria was dominant in formula-fed infants group A (FIG-A) at $73.46{\pm}4.12%$, but the proportions of phylum Actinobacteria were lower in formulafed infants group B and C (FIG-B and FIG-C) at $66.52{\pm}5.80%$ and $68.88{\pm}4.33%$. The most abundant genus in the BIG, FIG-A, FIG-B, and FIG-C was Bifidobacterium, comprising $73.09{\pm}2.31%$, $72.25{\pm}4.93%$, $63.81{\pm}6.05%$, and $67.42{\pm}5.36%$ of the total bacteria. Furthermore, the dominant bifidobacterial species detected in BIG and FIG-A was Bifidobacterium longum at $68.77{\pm}6.07%$ and $66.85{\pm}4.99%$ of the total bacteria. In contrast, the proportions of B. longum of FIG-B and FIG-C were $58.94{\pm}6.20%$ and $61.86{\pm}5.31%$ of the total bacteria. FIG-A showed a community similar to BIG, which may be due to the inclusion of galactooligosaccharide, galactosyllactose, synergy-oligosaccharide, bifidooligo and improvement material of gut microbiota contained in formula-milk. We conclude that 5-Bifidus factor contained in milk powder promotes the growth of Bifidobacterium genus in the intestines.