• Korean Journal of Veterinary Research
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• v.58 no.1
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• pp.45-49
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• 2018

The helicase genes and hypervariable regions (HVRs) of three avian hepatitis E viruses (HEVs) detected at three different farms were sequenced and characterized. Two isolates (DW-L and GI-B2) were classified as genotype 2 and one isolate (GR-B) was classified as genotype 1. A phylogenetic tree, based on the helicase gene and HVR nucleotide sequences, revealed the newly detected viruses and other avian HEVs were classified similarly. Unlike previously reported avian HEVs, the DW-L isolate detected in broiler breeders with characteristic lesions of avian HEV had no proline-rich motif in its HVR, suggesting that the proline-rich motif is non-essential for viral replication and infection.

• Korean Journal of Medicinal Crop Science
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• v.13 no.2
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• pp.69-74
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• 2005

Kalopanax pictus is a long-lived woody species mostly distributed in East Asia. K. pictus has been regarded as medically and ecologically important species in Korea. Thornless castor aralia variant, local name 'Cheongsong' is an endemic to Cheongsong province in Korea. Random amplified polymorphic DNA (RAPD) was used to investigate the genetic variation and structure of Korean populations of two species. A high level of genetic variation was found in six K. pictus populations. Twelve primers revealed 49 loci, of which 29 were polymorphic (59.2%). Nei's gene diversity for K.pictus and K. pictus variant were 0.119 and 0.098, respectively. Mean of genetic diversity in K. pictus was higher than average values for species with similar life history traits. The asexual and sexual reproduction, perennial habitat, and longevity are proposed as possible factors contributing to high genetic diversity. An indirect estimate of the number of migrants per generation (Nm=0.857) indicated that gene flow was not extensive among Korean populations of K.pictus. It is suggested that the isolation of geographical distance and reproductive isolation between K.pictus and K.pictus variant populations may have played roles in shaping the population structure of this species.

• Parasites, Hosts and Diseases
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• v.42 no.3
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• pp.129-135
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• 2004

We compared the DNA sequences of the genus Metagonimus: M. yokogawai, M. takahashii, and M. miyatai. We obtained 288 D1 ribosomal DNA (rDNA) and mitochondrial cytochrome c oxidase subunit I (mtCOI) fragments from the adult worms by PCR, that were cloned and sequenced. Phylogenetic relationships inferred from the nucleotide sequences of the 28S D1 rDNA and mtCOI gene. M. takahashii and M. yokogawai are placed in the same clade supported by DNA sequence and phylogenie tree analysis in 28S D1 rDNA and mtCOI gene region. The above findings tell us that M. takahashii is closer to M. yokogawai than to M. miyatai genetically. This phylogenetic data also support the nomination of M. miyatai as a separate species.

• The Korean Journal of Mycology
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• v.47 no.3
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• pp.181-186
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• 2019

A designated fungal isolate, KNU-US-1802E was isolated from the soil in Uiseong, Korea. To identify characteristics of the isolate, it was cultured on PDA media for 6 days at $35^{\circ}C$. Colonies on PDA are flat, light gray, dense, with entire margins; reverse dark gray to black, with white margins. Aerial mycelia were smooth-walled, hyaline and 40~42 mm diameter after 6 days at $35^{\circ}C$. Conidia were hyaline, one-celled, ellipsoidal to fusiform, forming long chains with average length ${\times}$ width of $5.0{\pm}0.3{\times}2.9{\pm}0.2{\mu}m$. Molecular analysis indicates that the internal transcribed spacer (ITS) region and partial beta-tubulin (tub2) gene sequence showed 100% and 99% similarities, respectively with Acrophialophora ellipsoidea CGMCC 3.15255 collected from China. Phylogenetic analysis by the neighbor-joining (NJ) method shows that the KNU-US-1802E was clustered with A. ellipsoidea CGMCC 3.15255 in a phylogenetic tree constructed using the concatenated sequences of ITS region and tub2 gene sequences with a high bootstrap value. Based on these findings, the isolate KNU-US-1802E was identified as Acrophialophora ellipsoidea, and this is the first report of this isolate in Korea.

• ETRI Journal
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• v.41 no.3
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• pp.358-370
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• 2019

The main aim of this study is to select the optimal set of genes from microarray cancer datasets that contribute to the prediction of specific cancer types. This study proposes the enhancement of the feature selection filter algorithm based on Joe's normalized mutual information and its use for gene selection. The proposed algorithm is implemented and evaluated on seven benchmark microarray cancer datasets, namely, central nervous system, leukemia (binary), leukemia (3 class), leukemia (4 class), lymphoma, mixed lineage leukemia, and small round blue cell tumor, using five well-known classifiers, including the naive Bayes, radial basis function network, instance-based classifier, decision-based table, and decision tree. An average increase in the prediction accuracy of 5.1% is observed on all seven datasets averaged over all five classifiers. The average reduction in training time is 2.86 seconds. The performance of the proposed method is also compared with those of three other popular mutual information-based feature selection filters, namely, information gain, gain ratio, and symmetric uncertainty. The results are impressive when all five classifiers are used on all the datasets.

• Parasites, Hosts and Diseases
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• v.59 no.1
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• pp.89-95
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• 2021

Microcotyle sebastis is a gill monogenean ectoparasite that causes serious problems in the mariculture of the Korean rockfish, Sebastes schlegelii. In this study, we isolated the parasite from fish farms along the coasts of Tongyeong, South Korea in 2016, and characterized its infection, morphology and molecular phylogeny. The prevalence of M. sebastis infection during the study period ranged from 46.7% to 96.7%, and the mean intensity was 2.3 to 31.4 ind./fish, indicating that the fish was constantly exposed to parasitic infections throughout the year. Morphological observations under light and scanning electron microscopes of the M. sebastis isolates in this study showed the typical characteristics of the anterior prohaptor and posterior opisthaptor of monogenean parasites. In phylogenetic trees reconstructed using the nuclear 28S ribosomal RNA gene and the mitochondrial cytochrome c oxidase I gene (cox1), they consistently clustered together with their congeneric species, and showed the closest phylogenetic relationships to M. caudata and M. kasago in the cox1 tree.

• Journal of Species Research
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• v.12 no.spc2
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• pp.33-44
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• 2023

In 2021, a total of 27 bacterial strains were isolated from soil, tree bark, moss, wetland, sea sediment, tidal flat, seawater and seaweed within Republic of Korea. Based on the analysis of 16S rRNA gene sequence (>98.7% sequence similarity), these isolates were assigned to the class Alphaproteobacteria as unrecorded species in Korea. The 27 strains were classified into the 10 families: Maricaulaceae of the order Caulobacterales; Brucellaceae, Methylobacteriaceae, Nitrobacteraceae and Rhizobiaceae of the order Hyphomicrobiales; Micropepsaceae of the order Micropepsales; Rhodobacteraceae of the order Rhodobacterales; Azospirillaceae of the order Rhodospirillales; and Erythrobacteraceae and Sphingomonadales of the order Sphingomonadaceae. There is no official report of these 27 species in Korea. Therefore, we report 27 isolates as unrecorded species, and described isolation sources, Gram-stain reactions, physiological and biochemical properties and morphologies of these strains.

• Journal of Species Research
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• v.13 no.1
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• pp.10-31
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• 2024

In this study, 11 strains of epilithic cyanobacteria belonging to six unrecorded species in Korea were isolated from gravel submerged in freshwater of seven collection sites in Korea. The morphological characteristics of the six species isolated in this study were consistent with the type strain of each species, and the similarity of the 16S rRNA gene sequences with the type strain of each species were 98.8-100%. In the phylogenetic tree using the 16S rRNA gene sequences, the 11 strains of these six species formed the same cluster as the strains of each species. The habitat of each previously reported species is mainly the soil surface, but all Korean strains appeared from the gravel submerged in freshwater. As a result of the morphological, ecological, and molecular analyses, these six species of cyanobacteria were identified as Geminocystis papuanica, Allocoleopsis franciscana, Ancylothrix terrestris, Klisinema persicum, Scytolyngbya timoleontis, and Shackletoniella antarctica, which were added as newly recorded species in Korea.

• Journal of Veterinary Science
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• v.25 no.1
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• pp.7.1-7.7
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• 2024

Background: Infections of cats with Echinococcus granulosus is uncommon because the cat is not part of the parasite life cycle that a carnivorous and another herbivore represent. Nevertheless, it occurs incidentally when eating food or drinking water contaminated with the worm's larva, especially with the presence of the definitive host (dogs), in this case, the infections are concentrated in stray or outside cats. For this reason, this study examined the possibility of cat infection with E. granulosus and diagnosed the common genotype of this infection. Objective: This study examined the possibility of cat infection with E. granulosus and diagnosed the common genotype of this infection. Methods: Four of the 37 cats that had died in different accidents developed cystic echinococcosis (CE). The cytochrome c oxidase subunit I (COX1) gene was initially amplified and sequenced to determine if these cysts belonged to E. granulosus, in beginning. The DNA fragments resulting from sequencing were then compared and aligned with other sequences using the Gene Bank database. Finally, a phylogenetic tree was drawn according to the sequence data obtained from cox1 genes sequencing, and the MEGA 7.0 phylogenetic analysis program was utilized. Results: Four different sequences were deposited in the Gen Bank with accession numbers (ON795961 to ON795964), all of which belong to the G1 genotype. Approximately 84% and 100% of these sequences aligned with G1 (AB622277.1) and G1 (MG722980.1), respectively. Conclusions: G1 is the dominant genotype that causes cat infections, even though the cat's EC infection was incidental.

• Journal of Korean Society of Forest Science
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• v.86 no.2
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• pp.167-176
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• 1997

Characteristics of leaf morphology and vegetation were examined in 6 populations of rare endemic tree species, Koelreuteria paniculata Laxm. Additionally we studied genetic variation employing isozyme marker. Nested anova showed that there were statistically significant differences among populations as well as among individuals within populations in all 8 leaf morphological traits. In 7 of 8 traits, variance components among populations were larger than those among individuals within populations. Only a few tree species were found within each population and all the populations seemed to have been disturbed by man. Level of genetic diversity for this rare endemic species was very low, especially compared with those of geographically widespread tree species(A/L=1.1, P=9.5%, $H_o=0.021$, $H_e=0.035$) and degree of genetic differentiation was high($F_{ST}=0.114$). Factors contributing to the low level of genetic diversity and high level of genetic differentiation might include genetic drift, inbreeding and limited gene flow. Finally, implications for the conservation of genetic diversity of Koelreuteria paniculata were discussed.