• Journal of fish pathology
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• v.22 no.3
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• pp.391-400
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• 2009

Genetic identification of 17 fish-derived Aeromonas strains was attempted using 5 housekeeping genes. 16S rRNA, gyrB, rpoD, dnaJ and recA genes from the 17 strains were amplified, and total of 85 amplicons were sequenced. DNA sequences of the strains and type strains of the 17 Aeromonas homology groups were used for genetic identification and phylogenetic analyses. None of the strains was identified as a single species using the 16S rRNA gene, showing the same identities (average = 99.7%) with several Aeromonas species. According to gyrB, rpoD, dnaJ, and recA, 9 strains and RFAS-1 used in this study were identified as A. hydrophila and A. salmonicida, respectively. However, the other strains were closely related to 2 or more Aeromonas species (i.e., A. salmonicida, A. veronii, A. jandaei, A. media and A. troda) depending on the genetic marker used. In this study, gyrB, rpoD, dnaJ and recA gene sequences proved to be advantageous over 16S rRNA for the identification of field Aeromonas isolates obtained from fish. However, there are discrepancies between analyses of different phylogenetic markers, indicating there are still difficulties in genetic identification of the genus Aeromonas using the housekeeping genes used in this study. Advantages and disadvantages of each housekeeping gene should be taken into account when the gene is used for identification of Aeromonas species.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.245-253
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• 2010

The base sequences representing human- and cow-specific 168 rRNA gene markers identified in a T-RFLP analysis were recovered from clone libraries. The human- and cow-specific primers were designed from these sequences and their specificities were analyzed with fecal DNAs from human, cow, and pig. The AllBac primer set showed positive results for all human, cow, and pig samples, whereas the human-specific primer set showed positive result only for the human sample but not for the cow or pig samples. Likewise, the cow-specific primer set showed positive results only for the cow sample but not for the human or pig samples. Real-time PCR assay with these primers was developed for the identification and quantification of fecal pollution in the river water. The human- and cow-specific markers were detected in the order of 9 $\log_{10}$ copies per gram wet feces, which were two orders of magnitude lower than those of total Bacteroidales. For the river water samples, the human-specific marker was detected in $1.7-6.2\;\log_{10}$ copies/100 ml water, which was 2.4-4.9 orders of magnitude lower than those of total Bacteroidales. There was no significant correlation between total Bacteroidales and conventional fecal indicators, but there was a high correlation between Bacteroidales and the human-specific marker. This assay could reliably identify and quantify the fecal pollution sources, enabling effective measures in the watersheds and facilitating water quality management.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.171-191
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• 2024

Identification of Helicotylenchus species is very challenging due to phenotypic plasticity and existence of cryptic species complexes. Recently, the use of rDNA barcodes has proven to be useful for identification of Helicotylenchus. Molecular markers are a quick diagnostic tool and are crucial for discriminating related species and resolving cryptic species complexes within this speciose genus. However, DNA barcoding is not an error-free approach. The public databases appear to be marred by incorrect sequences, arising from sequencing errors, mislabeling, and misidentifications. Herein, we provide a comprehensive analysis of the newly obtained, and published DNA sequences of Helicotylenchus, revealing the potential faults in the available DNA barcodes. A total of 97 sequences (25 nearly full-length 18S-rRNA, 12 partial 28S-rRNA, 16 partial internal transcribed spacer [ITS]-rRNA, and 44 partial cytochrome c oxidase subunit I [COI] gene sequences) were newly obtained in the present study. Phylogenetic relationships between species are given as inferred from the analyses of 103 sequences of 18S-rRNA, 469 sequences of 28S-rRNA, 183 sequences of ITS-rRNA, and 63 sequences of COI. Remarks on suggested corrections of published accessions in GenBank database are given. Additionally, COI gene sequences of H. dihystera, H. asiaticus and the contentious H. microlobus are provided herein for the first time. Similar to rDNA gene analyses, the COI sequences support the genetic distinctness and validity of H. microlobus. DNA barcodes from type material are needed for resolving the taxonomic status of the unresolved taxonomic groups within the genus.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.171-178
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• 2009

The Perciformes include approximately 40% of all bony fishes and are the largest order of vertebrates. This order includes some of the most economically relevant marine fishes, particularly the red seabream, black seabream and rock bream. A 409 bp fragment of the cytochrome b (cyt b) gene and 403 bp and 518 bp fragments of ribosomal RNA (12S and 16S rRNA, respectively) were sequenced from five populations of natural and cultured red seabreams, natural black seabream, and natural and cultured rock breams. The mitochondrial DNA sequences were utilized for the genetic identification and population structural analyses of these three species. Phylogenetic relationships of intra- and inter-species were elucidated using three types of molecular genetic markers from three species of the order Perciformes in Korea. We noted no significant differences in the intra-specific variation of the cyt b and rRNA genes in each population however, inter-specific divergences were greater than intra-specific variation. Inter-specific variation was induced more by transition than transversion type in the cyt b and rRNA genes. The cyt b gene and rRNA genes make it possible to determine the inter-species divergence. The rRNA genes have more conserved sequences than the cyt b gene. Therefore, these genes are expected to prove useful among species belonging to the different genera or families.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.3
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• pp.183-193
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• 2022

MicroRNAs (miRNAs) regulate gene expression and are biomarkers for coronary atherosclerosis (AS). A novel miRNA-mRNA regulation network of coronary AS still needs to be disclosed. The aim of this study was to analyze potential mRNAs in coronary AS patients and the role of their upstream miR-491-5p in vascular smooth muscle cells (VSMCs). We first confirmed top ten mRNAs according to the analysis from Gene Expression Omnibus database (GSE132651) and examined the expression levels of them in the plaques and serum from AS patients. Five mRNAs (UBE2G2, SLC16A3, POLR2C, PNO1, and AMDHD2) presented significantly abnormal expression in both plaques and serum from AS patients, compared with that in the control groups. Subsequently, they were predicted to be targeted by 11 miRNAs by bioinformatics analysis. Among all the potential upstream miRNAs, only miR-491-5p was abnormally expressed in the plaques and serum from AS patients. Notably, miR-491-5p overexpression inhibited viability and migration, and significantly increased the expression of contractile markers (α-SMA, calponin, SM22α, and smoothelin) in VSMCs. While silencing miR-491-5p promoted viability and migration, and significantly suppressed the expression of α-SMA, calponin, SM22α, and smoothelin. Overall, miR-491-5p targeted UBE2G2, SLC16A3, and PNO1 and regulated the dysfunctions in VSMCs.

• Animal Systematics, Evolution and Diversity
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• v.36 no.4
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• pp.347-353
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• 2020

Although sea slaters Ligia have a significant role in rocky shore habitats, their taxonomic entities have not been clearly understood. In this study, we investigated whether genetic variation inferred from a nuclear genetic marker, namely amplified fragment length polymorphism (AFLP), would conform to that of a mitochondrial DNA marker. Using both the mitochondrial DNA marker and the AFLP marker amplified by the six selective primer sets, we analyzed 95 Ligia individuals from eight locations from East Asia. The direct sequencing of mitochondrial 16S rRNA gene revealed three distinct genetic lineages, with 9.8-11.7 Kimura 2-parameter genetic distance. However, the results of AFLP genotyping analysis with 691 loci did not support those of mitochondrial DNA, and revealed an unexpectedly high proportion of shared polymorphisms among lineages. The inconsistency between the two different genetic markers may be explained by difference in DNA evolutionary history, for example inheritance patterns, effective population size, and mutation rate. The other factor is a possible genomic island of speciation, in that most of the genomic parts are shared among lineages, and only a few genomic regions have diverged.

• Journal of Microbiology and Biotechnology
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• v.33 no.10
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• pp.1376-1383
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• 2023

Recent studies have confirmed that gut microbiota differs according to race or country in many diseases, including mild cognitive impairment (MCI) and Alzheimer's disease. However, no study has analyzed the characteristics of Korean MCI patients. This study was performed to observe the association between gut microbiota and MCI in the Korean elderly and to identify potential markers for Korean MCI patients. For this purpose, we collected fecal samples from Korean subjects who were divided into an MCI group (n = 40) and control group (n = 40) for 16S rRNA gene amplicon sequencing. Although no significant difference was observed in the overall microbial community profile, the relative abundance of several genera, including Bacteroides, Prevotella, and Akkermansia, showed significant differences between the two groups. In addition, the relative abundance of Prevotella was negatively correlated with that of Bacteroides (r = 0.733). This study may provide Korean-specific basic data for comparing the characteristics of the gut microbiota between Korean and non-Korean MCI patients.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8893-8900
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• 2014

Dysregulated expression of microRNAs (miRNAs) has been shown to be closely associated with tumor development, progression, and carcinogenesis. However, their clinical implications for gastric cancer remain elusive. To investigate the hypothesis that genome-wide alternations of miRNAs differentiate gastric cancer tissues from those matched adjacent non-tumor tissues (ANTTs), miRNA arrays were employed to examine miRNA expression profiles for the 5-pair discovery stage, and the quantitative real-time polymerase chain reaction (qRTPCR) was applied to validate candidate miRNAs for 48-pair validation stage. Furthermore, the relationship between altered miRNA and clinicopathological features and prognosis of gastric cancer was explored. Among a total of 1,146 miRNAs analyzed, 16 miRNAs were found to be significantly different expressed in tissues from gastric cancer compared to ANTTs (p<0.05). qRT-PCR further confirmed the variation in expression of miR-193b and miR-196a in the validation stage. Down-expression of miR-193b was significantly correlated with Lauren type, differentiation, UICC stage, invasion, and metastasis of gastric cancer (p<0.05), while over-expression of miR-196a was significantly associated with poor differentiation (p=0.022). Moreover, binary logistic regression analysis demonstrated that the UICC stage was a significant risk factor for down-expression of miR-193b (adjusted OR=8.69; 95%CI=1.06-56.91; p=0.043). Additionally, Kaplan-Meier survival curves indicated that patients with a high fold-change of down-regulated miR-193b had a significantly shorter survival time (n=19; median survival=29 months) compared to patients with a low fold-change of down-regulated miR-193b (n=29; median survival=54 months) (p=0.001). Overall survival time of patients with a low fold-change of up-regulated miR-196a (n=27; median survival=52 months) was significantly longer than that of patients with a high fold-change of up-regulated miR-196a (n=21; median survival=46 months) (p=0.003). Hence, miR-193b and miR-196a may be applied as novel and promising prognostic markers in gastric cancer.

• Journal of Ecology and Environment
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• v.48 no.2
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• pp.120-127
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• 2024

Bats serve as vectors and natural reservoir hosts for various infectious viruses, bacteria, and fungi. These pathogens have also been detected in bat feces and can cause severe illnesses in hosts, other animals, and humans. Because pathogens can easily spread into the environment through bat feces, determining the bacterial communities in bat guano is crucial to mitigate potential disease transmission and outbreaks. This study primarily aimed to examine bacterial communities in the feces of insectivorous bats living in South Korea. Fecal samples were collected after capturing 84 individuals of four different bat species in two regions of South Korea, and the bacterial microbiota was assessed through next generation sequencing of the 16S rRNA gene. The results revealed that, with respect to the relative abundance at the phylum level, Myotis bombinus was dominated by Firmicutes (47.24%) and Proteobacteria (42.66%) whereas Miniopterus fuliginosus (82.78%), Rhinolophus ferrumequinum (63.46%), and Myotis macrodactylus (78.04%) were dominated by Proteobacteria. Alpha diversity analysis showed no difference in abundance between species and a significant difference (p < 0.05) between M. bombinus and M. fuliginosus. Beta-diversity analysis revealed that Clostridium, Asaia, and Enterobacteriaceae_g were clustered as major factors at the genus level using principal component analysis. Additionally, linear discriminant analysis effect size was conducted based on relative expression information to select bacterial markers for each bat species. Clostridium was relatively abundant in M. bombinus, whereas Mycoplasma_g10 was relatively abundant in R. ferrumequinum. Our results provide an overview of bat guano microbiota diversity and the significance of pathogenic taxa for humans and the environment, highlighting a better understanding of preventing emerging diseases. We anticipate that this research will yield bioinformatic data to advance our knowledge of overall microbial genetic diversity and clustering characteristics in insectivorous bat feces in South Korea.

• The Korea Journal of Herbology
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• v.30 no.3
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• pp.41-47
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• 2015

Objectives : Due to the morphological similarity of the pericarp and description of multi-species in National Pharmacopoeia of Korea and China, the Zanthoxylum Pericarpium is difficult to authenticate adulterant in species levels. Therefore, we introduced the sequence analysis of DNA barcode and identification of single nucleotide polymorphism(SNP) to establish a reliable tool for the distinction of Zanthoxylum Pericarpium from its adulterants. Methods : To analyze DNA barcode region, genomic DNA was extracted from twenty-four specimens of authentic Zanthoxylum species and inauthentic adulterant and the individual internal transcribed spacer regions (rDNA-ITS and ITS2) of nuclear ribosomal RNA gene were amplified using ITS1, ITS2-S2F, and ITS4 primer. For identification of species-specific sequences, a comparative analysis was performed using entire DNA barcode sequences. Results : In comparison of four Zanthoxylum ITS2 sequences, we identified 16, 4, 6, and 4 distinct species-specific nucleotides enough to distinguish Z. schinifolium, Z. bungeanum, Z. piperitum, and Z. simulans, respectively. The sequence differences were available genetic marker to discriminate four species. Futhermore, phylogenetic relationship revealed a clear classification between different Zanthoxylum species showing 4 different clusters. These results indicated that comparative analysis of ITS2 DNA barcode was an useful genetic marker to authenticate Zanthoxylum Pericarpium in species levels. Conclusions : The marker nucleotides, enough to distinguish Z. schinifolium, Z. piperitum, Z. bungeanum, and Z. simulans, were obtained at 30 SNP marker nucleotides from ITS2 sequences. These differences could be used to authenticate official Zanthoxylum Pericarpium from its adulterants as well as discriminating each four species.