• Journal of Life Science
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• v.26 no.7
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• pp.819-825
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• 2016

The present study was done to assess the diversity of the bacterial community associated with Ulva pertusa collected from Jeju Island using Restriction Fragment Length Polymorphism (RFLP) marker analysis. For RFLP analysis, a total of 145 bacterial strains associated with Ulva pertusa were screened and cultivated using Marine agar and R2A agar. The PCR amplicons of the 16S rRNA gene from all the isolated strains were digested with HaeIII and RsaI restriction enzymes and then classified into different groups according to their restriction patterns. Strains selected based on the RFLP patterns showed more than 91% 16S rRNA gene sequence similarity when compared with known bacterial species, which include 4 phyla - proteobacteria (alpha-proteobacteria, beta-proteobacteria, gamma-proteobacteria - 63%), firmicutes (11%), actinobacteria (4%), bacteroidetes (22%)–as well as 7 classes (actinobacteria, flavobacteriia, cytophagia, bacilli, α-proteobacteria, γ-proteobacteria, β-proteobacteria), 13 orders, 18 families, and 27 genera. These results confirmed a wide diversity of bacterial communities as contrasted with other regions. The newly isolated 10 strains, which show 16S rRNA sequence similarity of <97% compared to previously identified bacteria, could be noble species. Further experiments, such as morphological, physiological, and biochemical classification, are necessary to confirm the novelty of the newly isolated 10 strains.

• Molecules and Cells
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• v.40 no.4
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• pp.254-261
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• 2017

Glioblastomas (GBM) are very difficult to treat and their aggressiveness is one of the main reasons for this as well as for the frequent recurrences. MicroRNAs post-transcriptionally regulate their target genes through interaction between their seed sequence and 3'UTR of the target mRNAs. We previously reported that miR-296-3p is regulated by neurofibromatosis 2 (NF2) and enhances the invasiveness of GBM cells via SOCS2/STAT3. In this study, we investigated whether miR-296-5p, which originates from the same precursor miRNA as miR-296-3p, can increase the invasiveness of GBM cells. It was observed that miR-296-5p potentiated the invasion of various GBM cells including LN229, T98G, and U87MG. Through bioinformatics approaches, two genes were identified as miR-296-5p targets: caspase-8 (CASP8) and nerve growth factor receptor (NGFR). From results obtained from Ago2 immunoprecipitation and luciferase assays, we found that miR-296-5p downregulates CASP8 and NGFR through direct interaction between seed sequence of the miRNA and 3'UTR of the target mRNA. Knockdown of CASP8 or NGFR also increased the invasive ability of GBM cells, indicating that CASP8 and NGFR are involved in potentiation of invasiveness by miR-296-5p. Consistent with our findings, CASP8 was downregulated in brain metastatic lung cancer cells, which have a high level of miR-296-5p, compared to parental cells, suggesting that miR-296-5p may be generally associated with the acquisition of invasiveness. Collectively, our results implicate miR-296-5p as a potential cause of invasiveness in cancer and suggest it as a promising therapeutic target for GBM.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.880-884
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• 2001

Rumen microbiology research has undergone several evolutionary steps: the isolation and nutritional characterization of readily cultivated microbes; followed by the cloning and sequence analysis of individual genes relevant to key digestive processes; through to the use of small subunit ribosomal RNA (SSU rRNA) sequences for a cultivation-independent examination of microbial diversity. Our knowledge of rumen microbiology has expanded as a result, but the translation of this information into productive alterations of ruminal function has been rather limited. For instance, the cloning and characterization of cellulase genes in Escherichia coli has yielded some valuable information about this complex enzyme system in ruminal bacteria. SSU rRNA analyses have also confirmed that a considerable amount of the microbial diversity in the rumen is not represented in existing culture collections. However, we still have little idea of whether the key, and potentially rate-limiting, gene products and (or) microbial interactions have been identified. Technologies allowing high throughput nucleotide and protein sequence analysis have led to the emergence of two new fields of investigation, genomics and proteomics. Both disciplines can be further subdivided into functional and comparative lines of investigation. The massive accumulation of microbial DNA and protein sequence data, including complete genome sequences, is revolutionizing the way we examine microbial physiology and diversity. We describe here some examples of our use of genomics- and proteomics-based methods, to analyze the cellulase system of Ruminococcus flavefaciens FD-1 and explore the genome of Ruminococcus albus 8. At Illinois, we are using bacterial artificial chromosome (BAC) vectors to create libraries containing large (>75 kbases), contiguous segments of DNA from R. flavefaciens FD-1. Considering that every bacterium is not a candidate for whole genome sequencing, BAC libraries offer an attractive, alternative method to perform physical and functional analyses of a bacterium's genome. Our first plan is to use these BAC clones to determine whether or not cellulases and accessory genes in R. flavefaciens exist in clusters of orthologous genes (COGs). Proteomics is also being used to complement the BAC library/DNA sequencing approach. Proteins differentially expressed in response to carbon source are being identified by 2-D SDS-PAGE, followed by in-gel-digests and peptide mass mapping by MALDI-TOF Mass Spectrometry, as well as peptide sequencing by Edman degradation. At Ohio State, we have used a combination of functional proteomics, mutational analysis and differential display RT-PCR to obtain evidence suggesting that in addition to a cellulosome-like mechanism, R. albus 8 possesses other mechanisms for adhesion to plant surfaces. Genome walking on either side of these differentially expressed transcripts has also resulted in two interesting observations: i) a relatively large number of genes with no matches in the current databases and; ii) the identification of genes with a high level of sequence identity to those identified, until now, in the archaebacteria. Genomics and proteomics will also accelerate our understanding of microbial interactions, and allow a greater degree of in situ analyses in the future. The challenge is to utilize genomics and proteomics to improve our fundamental understanding of microbial physiology, diversity and ecology, and overcome constraints to ruminal function.

• Journal of Species Research
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• v.8 no.3
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• pp.249-258
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• 2019

Owing to a distinct environmental regime and anthropogenic effects, freshwater bacterial communities of urban streams are considered to be different from those of large freshwater lakes and rivers. To obtain unrecorded, freshwater bacterial species in Korea, water and sediment samples were collected from various urban streams of the Han River watershed in 2018. After plating the freshwater samples on R2A agar, approximately 1000 bacterial strains were isolated from the samples as single colonies and identified using 16S rRNA gene sequence analyses. A total of 26 strains, with >98.7% 16S rRNA gene sequence similarity with validly published bacterial species but not reported in Korea, were determined to be unrecorded bacterial species in Korea. The unrecorded bacterial strains were phylogenetically diverse and belonged to four phyla, six classes, 12 orders, 16 families, and 21 genera. At the generic level, the unreported species were assigned to Nocardioides, Streptomyces, Microbacterium, Kitasatospora, Herbiconiux, Corynebacterium, and Microbacterium of the class Actinobacteria; Paenibacillus and Bacillus of the class Bacilli; Caulobacter, Methylobacterium, Novosphingobium, and Porphyrobacter of the class Alphaproteobacteria; Aquabacterium, Comamonas, Hydrogenophaga, Laribacter, Rivicola, Polynucleobacter, and Vogesella of the class Betaproteobacteria; Arcobacter of the class Epsilonproteobacteria; and Flavobacterium of the class Flavobacteriia. The details of the 26 unreported species, including Gram reaction, colony and cell morphology, biochemical properties, and phylogenetic position are also provided in the strain descriptions.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.211-226
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• 2000

Genetic divergence and phylogenetic relationships among the major Korean fireflies (Hotaria papariensis, Luciola lateralis, and Pyrocoelia rufa) were studied. A portion of mitochondrial COI (403 bp) and 165 rRNA (490~504 bp) genes were sequenced, and the GenBank-registered, homologous 165 rRNA sequences of Japanese fireflies were compared (27 species of Lampyridae, one of Lycidae, and one of Rhgophthalmidae). Greatest DNA and/or amino acid sequence divergence was found when P rufa, belonging to Lampyrinae was compared with H. papariensis and L. lateralis, both belong-ing to Luciolinae, confirming the current taxonomic status of the species. In the PAUP and PHYLIP analyses with 165 rRNA data, grouping of the two geographic samples of H. papariensis with H. tsushimana validate the use of generic name, Hotaria. Nevertheless, lack of sister-group relationship of the two geographic samples of H. papariensis renders further investigation on this group . Although the Korean and Japanese L. lateralis formed a strong monophyletic group, a substantial genetic differentiation was detected between them (2.9% of 165 rRNA gene sequence divergence). Finally, the geographic samples of Korean p. rufa strongly formed a group with Japanese p. rufa, warranting the use of generic name, Pyrocoelia, but the genetic distance observed between the Cheju-Island individual and all others requires further investigation on this subject. Summarized, this study supports the current taxonomic status of the Korean fireflies in that each respectively formed a strong monophyletic group with its own species or genus.

• The Plant Pathology Journal
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• v.27 no.2
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• pp.148-155
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• 2011

Our previous sequence and phylogenetic analyses of the Korean Rice stripe virus (RSV) suggested possible genetic reassortment of RNA segments, but whether this RNA variation contributed to the recent RSV outbreaks in Korea is yet unclear. To further clarify these RSV-RNA segment variations, we developed a reverse transcription-polymerase reaction/restriction enzyme (RT-PCR/RE) analysis-based method. We identified five REs, including DraI, EcoR1, NdeI/AseI, and SpeI, that could differentiate RSV RNA 1-4 subtypes, respectively. Our RT-PCR/RE results provided a clear pattern of RNA reassortment, i.e., different groups of isolates having their RNA segments derived from two to three different RSV ancestors, such as from Eastern and Southwestern Chinese or Japanese M and T isolates. We also found that the migratory small brown planthopper from Eastern China caught by aerial net traps that possesses RSV-RNA3 genotypes corresponds mainly to Eastern China, with a few for Southwestern China based on RT-PCR/RE, sequence and phylogenetic analyses, indicating that RSV populations in Eastern China may also have strong RNA variation. The development of an RE analysisbased method proved a useful epidemiological tool for rapid genotyping and identification of mixed infections by RSV strain and by different subtype.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.913-915
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• 2012

RNA polymerase beta subunit gene (rpoB) mutation of rifampin-resistant Mycobacteria was analyzed using nucleotide sequence of rpoB DNA (351 bp) containing rifampin resistant region, $rif^r$. For this purpose, we collected rifampin-resistant Mycobacteria that were identified by conventional culture method from Masan National Hospital and The Korean Institute of Tuberculosis and performed analysis of nucleotide sequence of rpoB of them. We found various mutations of rpoB linked rifampin resistant gene from rifampin-resistant Mycobacteria. From this study, we identified mutations of different codons from codons that have been reported recently.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.300-302
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• 2019

Glutamicibacter halophytocola DR408 isolated from the rhizospheric soil of soybean plant at Jecheon showed drought tolerance and plant growth promotion capacity. The complete genome of strain DR408 comprises 3,770,186 bp, 60.2% GC-content, which include 3,352 protein-coding genes, 64 tRNAs, 19 rRNA, and 3 ncRNA. The genome analysis revealed gene clusters encoding osmolyte synthesis and plant growth promotion enzymes, which are known to contribute to improve drought tolerance of the plant.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.605-613
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• 2022

The genus Flavobacterium, type genus of the family Flavobacteriaceae and a member of the phylum Bacteriodetes includes gram-negative and yellow-pigmented rods. Those bacteria have been isolated from various environments of the earth. A yellow-pigmented, gram-negative rod was isolated from a pond in the campus of the Changwon University, Changwon, Kyeongnam and designated as strain B1. Strain B1 was further analyzed physiologically, biochemically and phylogenetically, and concluded to be a member of genus Flavobacterium. BLAST search of the 16S rRNA gene sequence of strain B1 shows homology no higher than 99.0% with those sequences of other bacteria. The major fatty acids of strain B1 are iso-C_15:0 (19.6%), summed feature 3(C_16:1 ω7c and/or C_16:1 ω6c, 16.1%), iso-C_17:0 3OH(10.2%), iso-C_15:0 3OH(8.4%) and iso-C_15:1 G(6.6%) showing significant differences in fatty acid compositions between strain B1 and the other known Flavobacterium species. DNA sequence of 16S rRNA gene of strain B1 was deposited in genbank under accession number OP060681.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.515-523
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• 2001

The dinoflagellates have some primitive nuclear features and are evolutionarily intermediate between prokaryotes and eukaryotes. The small subunit ribosomal RAN gene, the 5.8S ribosomal RNA gene, and the internal transcribed spacer (ITS) of Gonyaulax polyedra were cloned, and their sequences were analyzed to better understand their evolutionary position. The small subunit ribosomal RNA gene was 1,794 nt long, the large subunit ribosomal RNA gene was approximately 3,500 nt long, and the 5.8S ribosomal RNA gene was 159 nt long. The first internal transcribed spacer (ITS1) was 191 nt long, and the second internal transcribed spacer (ITS2) was 185 nt long. The intergenic spacer of the ribosomal RNA gene (IGS) was about 2,200 nt long, indicating that 5,800 nt of transcribed sequences were separated by roughly 2,200 nt of intergenic spacer. The ribosomal RNA genes were repeated many times and arranged in a head-to-tail, tandemly repeated manner. The repeating unit of ribosomal RNA gene of G. polyedra was proposed to be 8,000 nt long. Based on the lengths of ribosomal RNA, sequence alignments with representative organisms, and phylogenetic analysis on ribosomal RNA, G. polyedra appears to be one of the alveolates branched from the eukaryotic crown and, among dinoflagellates, it seems to not have emerged early.