• Journal of Microbiology
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• v.42 no.1
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• pp.9-13
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• 2004

Culture-independent approaches, based on 16S rDNA sequences, are extensively used in modern microbial ecology. Sequencing of the clone library generated from environmental DNA has advantages over fingerprint-based methods, such as denaturing gradient gel electrophoresis, as it provides precise identification and quantification of the phylotypes present in samples. However, to date, no method exists for comparing multiple bacterial community structures using clone library sequences. In this study, an automated method to achieve this has been developed, by applying pair wise alignment, hierarchical clustering and principle component analysis. The method has been demonstrated to be successful in comparing samples from various environments. The program, named CommCluster, was written in JAVA, and is now freely available, at http://chunlab.snu.ac.kr/commcluster/.

• Animal Systematics, Evolution and Diversity
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• v.38 no.4
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• pp.149-156
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• 2022

The magelonid polychaete Magelona parochilis Zhou and Mortimer, 2013 is newly reported from South Korea. The Korean specimens correspond well to the original description of M. parochilis in having prostomium without horn, mucronate chaetae on chaetiger 9, superior dorsal lobes on chaetigers 1-8, ventral neuropodial lobes on chaetiger 9, smooth edged thoracic notopodial lamellae, and unidirectional tridentate hooded hooks on abdominal chaetigers. Partial sequences of cytochrome c oxidase I (COI) and 16S ribosomal DNA (16S rDNA) of the species were determined from Korean specimens. The detailed description and illustrations are provided with partial sequences of COI and 16S rDNA as molecular markers for species identification.

• Journal of the Korean Chemical Society
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• v.46 no.2
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• pp.157-163
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• 2002

To identify RNA motifs interacting with $tRNA^{Val}$, a SELEX(Systematic Evolution of Ligands by Exponential Enrichment) was applied. Random DNA library which contains a region of ran-domized 48-mer oligonucleotide flanked by conserved sequ ence primers was transcribed into RNA pool using T7 RNA polymerase and RNA aptamers were selected with $tRNA^{Val}$ -immobilized affinity column through 14 rounds of SELEX. Some of the resulting aptamers contained a consensus sequence similar to the sequence in the loop regions of three rRNAs; C43GAAC47 sequence of 5S rRNA, G1491AAGU1495, G1379UUCC1383 sequence of 16S rRNA and C1064UUAG1068, G2110UGUA2114, C2480GACGG2485, A2600CAGU2604 sequence of 23S rRNA. These results suggest that $tRNA^{Val}$ can interact with 5S rRNA, 16S rRNA and 23S rRNA with variety in ribosome.

• Mycobiology
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• v.28 no.1
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• pp.11-16
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• 2000

The nucleotide sequences of the internal transcribed spacer (ITS) regions of the ribosomal DNA including the 5.8S ribosomal RNA gene (rDNA) have been determined for 11 species in order to analyze their intrageneric relationships. The total length of these sequences ranged from 530 nucleotides for Trichoderma reesei KCTC 1286 to 553 nucleotide for Trichoderma koningii IAM 12534. Generally speaking, the length of ITS1 region was about 30 nucleotides longer than that of the ITS2 region. Also, the sequences of 5.8S rDNA were more conserved in length and variation than those of ITS regions. Although the variable ITS sequences were often ambiguously aligned, the conserved sites were also found. Thus, a neighbor-joining tree was constructed using the full sequence data of the ITS regions and the 5.8S rDNA. The Trichoderma genus used to be grouped on the basis of the morphological features and especially the shape of phialides needs to be reexamined. The phylogenetic tree displayed the presence of monophylogeny in the species of Trichoderma. Therefore, it was difficult to distinguish the intrageneric relationships in the Trichoderma genus.

• Korean Journal of Microbiology
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• v.34 no.3
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• pp.132-136
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• 1998

Molecular analyses of natural microbial communities are often dependent upon the obtainments of pure nucleic acids. The four methods (elution after agarose gel electrophoresis, G-75 microspin columns, hydroxyapatite mi-crospin columns, and polyvinylpolypyrrolidone (PVPP) microspin columns) were compared for the removal of PCR-inhibitory humic substances from the crude DNA extracts of marine sediment samples. The PVPP microspin columns have shown superior removal of humic substances from the crude DNA extract of marine sediment samples, with yield of $4.8{\mu}g/g$ (dry weight of sediment). The purified DNA by this rapid method was pure enough to amplify 1.5 kb fragment corresponding almost full length of 16S rRNA genes.

• Korean Journal of Medicinal Crop Science
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• v.14 no.4
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• pp.250-254
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• 2006

To elucidate cytogenetic differences, karyotype analysis and FISH (fluorescence in situ hybridization) with 45S and 5S rDNAs were carried out in the three Astragalas species: Astragalas membranaceus Bunge, A. membranaceus var. alpinus Nakai and A. mongholicus Bunge. The somatic metaphase chromosome numbers of all three species were 2n=2x=16 and the size of chromosomes ranged $2.19{\sim} 5.73\;{\mu}m$. The chromosome complement of A. membranaceus consisted of each four pairs of metacentrics (chromosomes 3,4,6 and 7) and submetacentrics (chromosomes 1,2,4 and 8). In A. membranaceus var. alpinus, the chromosome complement consisted of two pairs of metacentrics (chromosomes 4 and 8) and six pairs of submetacentrics (chromosomes 1,2,3,5,6 and 7). A. mongholicus had three pairs of metacentrics (chromosomes 6,7 and 8) and five pairs of submetacentrics (chromosomes 1,2,3,4 and 5). Using bicolor-FISH, one pair of 45S and 5S rDNA signals could be detected on the centromeric regions of chromosomes 8 and 7 of A. membranaceus and A. mongholicus, respectively. In contrast, A, membranaceus var. alpinus had one pair of 45S signals on the centromeric region of chromosome 8 and two pairs of 5S rDNA signals on the short arms of chromosomes 7 and 8.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.438-441
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• 2003

The present study reports the novel physiological function of dissimilatory perchlorate reduction by two strains JB101 and JB109 isolated from a sewage treatment facility in Incheon, South Korea. The physiological data of the isolates showed good correspondence with the members of the family Enterobacteriaceae. The partial 16S rRNA and 16S rDNA sequence of strains JB101 and JB109 showed similarity of 99.8% to Citrobacter amalonaticus and 98% to Citrobacter farmari, respectively. The study infers toward possibility of Citrobacter spp. to form an important group of dissimilatory perchlorate reducers within the (equation omitted) subclass of Proteobacteria because the majority of the known. members belong to two monophyletic groups namely Dechloromonas and Dechlorosoma in $\beta$ subclass of Proteobacteria.

• Biomedical Science Letters
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• v.6 no.1
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• pp.65-72
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• 2000

In order to improve the early diagnosis of Johne's disease in ruminants, duplex polymerase chain reaction system for the detection of the etiologic agent of M. paratuberculosis and for the differentiation of other mycobacterial animal pathogens, such as M. bovis and M. avium, was applied. Genomic DNAs were purified from peripheral blood monocytes or milk macrophages and were used as templates in the duplex PCR. Detection of Mycobacterium spp. in the specimen was carried out by PCR using primer set specific to the mycobacterial 16S rDNA. And then, mycobacterial DNA-positive specimens were further differentiated with duplex PCR system which was composed of primer sets specific to 16S rDNA of M. avium complex and Is900 gene of M. paratuberculosis. The results were re-confirmed by Southern blot hybridization with oligonucleotide specific to the internal sequence of IS900 PCR amplicons. The applicability of this duplex PCR system was evaluated with DNAs extracted from clinical specimens of peripheral blood monocytes and milk macrophages. In summary, the duplex PCR amplification system described in this experiment is promising molecular technique for the early diagnosis of Johne's disease in ruminants.

• International Journal of Oral Biology
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• v.42 no.3
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• pp.143-147
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• 2017

In a previous study, Peptoniphilus mikwangii was isolated from the human oral cavity as a new species. The purpose of this study was to develop P. mikwangii-specific PCR primers. The PCR primers were designed, based on the nucleotide sequence of 16S ribosomal RNA (16S rDNA). The specificity of the primers was tested using genomic DNAs of 3 strains of P. mikwangii and 27 strains (27 species) of non-P. mikwangii bacteria. The sensitivity of primers sensitivity was determined using PCR, with serial dilutions of the purified genomic DNAs (4 ng to 4 fg) of P. mikwangii KCOM $1628^T$. The data showed that P. mikwangii-specific qPCR primers (B134-F11/B134-R1 & B134-F5/B134-R5) could detect only P. mikwangii strains, and 400 fg or 40 fg of P. mikwangii genome DNA. These results suggest that PCR primers are useful in detecting P. mikwangii from the oral cavity.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.255-261
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• 2010

The bacterial community structure associated with two marine sponges, Hyrtios sp. 604 and Callyspongia sp. 612 collected from the South Pacific Ocean were analyzed by 16S rDNA-denaturing gradient gel electrophoresis (DGGE). The phylogenetic analysis showed that the bacterial community associated with Hyrtios sp. 604 contained diverse bacterial groups such as Chloroflexi, Firmicutes, Cyanobacteria, Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Acidobacteria. Callyspongia sp. 612 harbored Chloroflexi, Cyanobacteria, Alphaproteobacteria, and Gammaproteobacteria. Hyrtios sp. 604 belonging to genus Hyrtios known to produce natural products showed greater bacterial diversity than Callyspongia sp. 612. Phylum Actinobacteria was shown to be one of dominant bacterial groups in Hyrtios sp. 604. Although the same phyla of bacteria were found in both sponge species, the spongeassociated predominant bacterial groups differed between the two sponges with different chemical characteristics from the same geographical location. Uncultured bacteria represented over 90% of the bacteria diversity present in all bacterial communities of the sponges.