• Journal of the Korean Magnetic Resonance Society
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• v.21 no.3
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• pp.109-113
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• 2017

The hepatitis C virus (HCV) internal ribosome entry site (IRES) is an RNA structure located in the 5'-UTR of the HCV RNA genome. The HCV IRES consists of four domains I, II, III, and IV, where domains II - IV are recognized by 40S ribosomal subunit and the domain III is bound to eukaryotic initiation factor 3 (eIF3) for translation initiation. Here, we have characterized the tertiary interaction between an L-/K- rich peptide and the HCV IRES domain IV. To probe the peptide binding interface in RNA, we synthesized $^{13}C$- and $^{15}N$-double labeled RNA and the binding site was identified by using the chemical shift perturbation (CSP) NMR methods. Our results showed that the peptide binds to the upper stem of the IRES domain IV, indicating that the tertiary interaction between the IRES domain IV and the peptide would disrupt the initiation of translation of HCV mRNA by blocking the start codon exposure. This study will provide an insight into the new peptide-based anti-viral drug design targeting HCV IRES RNA.

• ALGAE
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• v.33 no.1
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• pp.49-54
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• 2018

Red algal mitochondrial genomes (mtDNAs) can provide useful information on species identification. mtDNAs of Pyropia / Porphyra (Bangiales, Rhodophyta) have shown diverse variation in their size and gene structure. In particular, the introns and intronic open reading frames found in the ribosomal RNA large subunit gene (rnl) and cytochrome c oxidase subunit 1 gene (cox1) significantly vary the mitochondrial genome size in Pyropia / Porphyra species. In this study, we examined the exon / intron structure of rnl and cox1 genes of Pyropia yezoensis at the intraspecific level. The combined data of rnl and cox1 genes exhibited 12 genotypes for 40 P. yezoensis strains, based on the existence of introns. These genotypes were more effective to identify P. yezoensis strains in comparison to the traditional DNA barcode cox1 marker (5 haplotypes). Therefore, the variation in gene structure of rnl and cox1 can be a novel molecular marker to discriminate the strains of Pyropia species.

• International Journal of Oral Biology
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• v.45 no.2
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• pp.70-75
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• 2020

The aim of this study was to identify strain KCOM 1265 isolated from subgingival plaque at the species level by comparing 16S ribosomal RNA gene (16S rDNA) and genome sequences. The whole genome of strain KCOM 1265 was extracted using the phenol-chloroform extraction method. 16S rDNA was amplified using polymerase chain reaction and sequenced using the dideoxy chain termination method. Pairwise genome comparison was performed using average nucleotide identity (ANI) and genome-to-genome distance (GGD) analyses. The data showed that the percent similarity of 16S rDNA sequence of strain KCOM 1265 was 99.6% as compared with those of Fusobacterium polymorphum ATCC 10953^T and Fusobacterium hwasookii KCOM 1249^T. The ANI values of strain KCOM 1265 with F. polymorphum ATCC 10953^T and F. hwasookii KCOM 1249^T were 95.8% and 93.0%, respectively. The GGD values of strain KCOM 1265 with F. polymorphum ATCC 10953^T and F. hwasookii KCOM 1249^T were 63.9% and 49.6%, respectively. These results indicate that strain KCOM 1265 belongs to F. polymorphum.

• The Korean Journal of Mycology
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• v.51 no.4
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• pp.505-510
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• 2023

In June 2023, at the oat field on Kongju National University's Yesan Campus, flies infected with an entomopathogenic fungus were discovered. The flies were hanging with their wings folded backward. Fungal mycelia had sprouted on the abdomens of the flies. An analysis of the 28S ribosomal RNA sequence confirmed that the fungus was Entomophthora muscae. Moreover, cytochrome oxidase sequence analysis of the host insect identified it as Delia platura.

• Journal of Aquaculture
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• v.6 no.3
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• pp.221-233
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• 1993

Cell size, DNA content, chromosome and PCR-based mitochondrial 12S rRNA gene analyses were conducted to obtain basic informations for genetic stock identification of spotted flounder (Verasper variegatus) from Yeocheun, Korea. The mean erythrocytic and nuclear volumes of spotted flounder were $211.10{\mu}m^3$ and $23.03{\mu}m^3$, respectively. The haploid DNA content of this species was 0.79 pg/cell which correspond to $46.5\%$ of carp and to $22.6\%$ of mammals. Spotted flounder had the 2n = 46 acrocentric chromosomes but no heteromorphic sex chromosomes was found. Mitochondrial DNA gene for 12S ribosomal RNA was amplified by polymerase chain reaction (PCR) and the PCR products were subjected to digestion with 15 restriction endonucleases. Restriction enzyme analyses revealed that Ava I, Mae II, Sma I and Xba I had one restriction site in the mitochondrial 12S rRNA gene segment of spotted flounder, while Mae I had two. Segments of 12S rRNA gene from mitochondria in spotted flounder were sequenced and compared with channel catfish and human as controls. The 12S rRNA gene of this species was more similar to that of channel catfish than to human's.

• Molecules and Cells
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• v.27 no.5
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• pp.539-546
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• 2009

In Saccharomyces cerevisiae, ribosomal protein L7, one of the ~46 ribosomal proteins of the 60S subunit, is encoded by paralogous RPL7A and RPL7B genes. The amino acid sequence identity between RPl7a and RPl7b is 97 percent; they differ by only 5 amino acid residues. Interestingly, despite the high sequence homology, Rpl7b is detected in both the cytoplasm and the nucleolus, whereas Rpl7a is detected exclusively in the cytoplasm. A site-directed mutagenesis experiment revealed that the change in the amino acid sequence of Rpl7b does not influence its subcellular localization. In addition, introns of RPL7A and RPL7B did not affect the subcellular localization of Rpl7a and Rpl7b. Remarkably, Rpl7b was detected exclusively in the cytoplasm in rpl7a knockout mutant, and overexpression of Rpl7a resulted in its accumulation in the nucleolus, indicating that the subcellular localization of Rpl7a and Rpl7b is influenced by the intracellular level of Rpl7a. Rpl7b showed a wide range of localization patterns, from exclusively cytoplasmic to exclusively nucleolar, in knockout mutants for some rRNA-processing factors, nuclear pore proteins, and large ribosomal subunit assembly factors. Rpl7a, however, was detected exclusively in the cytoplasm in these mutants. Taken together, these results suggest that although Rpl7a and Rpl7b are paralogous and functionally replaceable with each other, their precise physiological roles may not be identical.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.218-223
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• 2004

Myxobacteria are Gram-negative soil bacteria known to be a rich source of potentially useful secondary metabolites. We have isolated 204 strains of bacteriolytic myxobacteria from soil samples collected in Korea and determined their 16S rRNA sequences. Sequence analysis of the partially determined 16S rRNA sequences has suggested that 132 isolates (65% of total isolates) belong to the genus Myxococcus and 59 isolates (29% of total isolates) belong to the genus Corallococcus. Meanwhile, 4 isolates appear to be Archangium spp. and the other 4 isolates appear to be Stigmatella spp. Genera of the remained 5 isolates have not been identified because their 16S rRNA sequences are distantly related to those of known myxobacteria.

• Journal of Life Science
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• v.28 no.2
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• pp.257-264
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• 2018

The YrdC superfamily is a group of proteins that are highly conserved in almost all organisms sequenced so far. YrdC in Escherichia coli was suggested to be involved in ribosome biogenesis, translation termination, cold adaptation, and threonylcarbamoyl adenosine formation in tRNA. In this study, to unambiguously demonstrate that yrdC is essential in E. coli, we constructed two yrdC mutant strains of E. coli and examined their phenotypes. In the temperature-sensitive yrdC mutant strain, cell growth stopped almost immediately under nonpermissive conditions and it appeared to accumulate 16S ribosomal RNA precursors without significant accumulation of 30S ribosomal subunits. We also cloned yeast and human homologs and demonstrated that they complement the E. coli yrdC-deletion strain. By mutational study, we demonstrated that the concave surface in the middle of the YrdC protein plays an important role in E. coli, yeast, and human versions. By comparison of two yrdC-deletion strains, we also unambiguously demonstrated that yrdC is essential for viability in E. coli and that the functions of its yeast and human homologs overlap with that of E. coli YrdC.

• Parasites, Hosts and Diseases
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• v.51 no.5
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• pp.511-517
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• 2013

Species identification using DNA sequences is the basis for DNA taxonomy. In this study, we sequenced the ribosomal large-subunit RNA gene sequences (3,037-3,061 bp) in length of 13 Chinese Theileria stocks that were infective to cattle and sheep. The complete 28S rRNA gene is relatively difficult to amplify and its conserved region is not important for phylogenetic study. Therefore, we selected the D2-D3 region from the complete 28S rRNA sequences for phylogenetic analysis. Our analyses of 28S rRNA gene sequences showed that the 28S rRNA was useful as a phylogenetic marker for analyzing the relationships among Theileria spp. in ruminants. In addition, the D2-D3 region was a short segment that could be used instead of the whole 28S rRNA sequence during the phylogenetic analysis of Theileria, and it may be an ideal DNA barcode.

• Plant Biotechnology Reports
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• v.5 no.3
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• pp.289-295
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• 2011

The SpoU family of proteins catalyzes the methylation of transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs). We characterized a putative tRNA/rRNA methyltransferase, VaSpoU1 of the SpoU family, from Viscum album (mistletoe). VaSpoU1 and other plant SpoU1s exhibit motifs of the SpoU methylase domain that are conserved with bacterial and yeast SpoU methyltransferases. VaSpoU1 transcripts were detected in the leaves and stems of V. album. VaSpoU1-GFP fusion proteins localized to both chloroplasts and mitochondria in Arabidopsis protoplasts. Sequence analysis similarly predicted that the plant SpoU1 proteins would localize to chloroplasts and mitochondria. Interestingly, mitochondrial localization of VaSpoU1 was inhibited by the deletion of a putative N-terminal presequence in Arabidopsis protoplasts. Therefore, VaSpoU1 may be involved in tRNA and/or rRNA methylation in both chloroplasts and mitochondria.