• Journal of fish pathology
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• v.33 no.2
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• pp.127-138
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• 2020

We attempted to isolate and identify potentially pathogenic bacteria from geoduck clam (Panopea japonica) larvae, juvenile and adult, focusing on Vibrios. The isolates were identified by molecular approach and biochemical characterization. In particular, we applied MLSA (multilocus sequence analysis) to the isolated Vibrios for clear identification and phylogenetic relationships, by combining 16s rDNA and several houskeeping genes (pyrH, recA, rpoA). We obtained 141 isolates; 10 from healthy adults, 52 from moribund adults with blisters and 79 from larvae. 46 from the moribund adults and 39 from the larvae were identified as Vibrio species, while the rest of these samples and all the isolates from healthy adult were identified as marine general bacteria. Among Vibrio species, Vibrio splendidus was the most frequently identified from the moribund adults and clustered with the known V. splendidus in GenBank by MLSA. However, it was still unclear that V. splendidus was the cause of blisters because the artificial infection experiment was not conducted and V. splendidus was isolated also from the larvae. Further studies are necessary to clarify the etiological agent of the blisters found in geoduck clam in this study.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.26-34
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• 2015

Korean Poaceae includes approximately 80 species of the agricultural weeds. Precise species identification is the first step for more effective weed management in the agricultural fields. However, the identification of species in Poaceae is not easy without the assistance of taxonomists or identification experts although they are relatively easy to distinguish from the plants of the other family by the unique characteristics of caryopsis. Thus, DNA barcode was suggested as an alternative powerful technique for species identification by using short sections of DNA from a specific region of the genome. Two standard barcode markers of vascular plants, chloroplast rbcL and matK, and a supplementary nuclear ribosomal Internal Transcribed Spacer (ITS) region were used for barcode of major Korean Poaceae weeds, 403 individuals of 84 taxa. All the barcode markers revealed a good level of sequencing success with the lowest 73.7% for matK and the highest 88.8% for rbcL. The barcode sequences were deposited to the National Center for Biotechnology Information (NCBI) database for public use. Combined matK and ITS showed very high resolving power with 92.9%. Besides the identification of weeds for weed managment, the generated DNA barcode data could be used for many other applications such as rapid biodiversity assessment and conservation prioritization.

• Research in Plant Disease
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• v.17 no.1
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• pp.82-85
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• 2011

Bakanae disease symptom were observed in barnyard grass in paddy field in Heanam, Jeonnam. The infected plants were blighted and white mass of spore were formed on the stem. Fusarium species were isolated from infected stem and the isolates were identified as Fusarium fujikuroi based on their morphological and molecular characteristics. The isolates of F. fujikuroi were assigned to reference of F. fujikuroi among related Fusarium species based on the translation elongation factor 1-alpha gene sequence. Pathogenicity of the fungal isolates was confirmed on seedlings of rice and barnyard grass by artificial inoculation. The results indicated that barnyard grass can be inoculum source of Bakanae disease on rice. Thus, effective weed management is necessary to Bakanae disease control and healthy seed production.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.83-89
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• 2015

Although Mycobacterium tuberculosis complex strains remain responsible for the majority of diseases caused by mycobacterial infections worldwide, the increase in HIV (human immuno deficiency virus) infections has allowed for the emergence of other non-tuberculous mycobacteria as clinically significant pathogens. M. tuberculosis was detected by two-tube nested polymerase chain reaction (PCR) and non-tuberculous mycobacteria was detected by PCR-restriction fragment length polymorphism (RFLP) with Msp I. Result of niacin test is equal to result of two-tube nested PCR after culture for M. tuberculosis. In this study, acid fast bacilli stain (AFB. stain) >2+ case, Detection of Mycobacteria is similar to result before culture and after culture. AFB. stain <1+ case, result of mycobacteria is distinguished. Conclusionly, these results suggest that identification of mycobacteria must go side by side both culture and PCR for more fast and accuracy.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.159-163
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• 1999

Recent development of the molecular biology techniques has made it possible to characterize and analyze early diagnoses of genetic disorders and economic trait loci. In this study, porcine genomic DNA was extracted from both clotted and dried blood to analyze the porcine estrogen receptor (ER) gene by polymerase chain reaction (PCR). By the methods reported here, genomic DNA extracted from clotted or dried blood was efficient enough to detect ER gene by PCR. Moreover, the PCR-RFLP (restriction fragment length polymorphism) of ER gene was identified by PvuII restriction enzyme. Thus the results obtained from this study show that the clotted and dried blood was useful for identification of the certain genotype in a rapid manner with low cost. Importantly, this study implies that the whole blood can be economically utilized in studies of endocrinology, molecular biology, and genetics by obtaining both serum and DNA simultaneously in an efficient manner.

• The Korean Journal of Mycology
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• v.40 no.1
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• pp.1-6
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• 2012

In this study, soil samples were collected from cultivated fields of 1-5 year old Korean ginseng in Geumsan, Korea. Spores of arbuscular mycorrhizal fungi were extracted from soils and identified using morphological characteristics and 18s rDNA sequences of the spores. Total 10 species of AMF were identified: Acaulospora longula, Archaeospora trappei, Glomus caledonium, Glomus etunicatum, Glomus intraradices, Glomus mosseae, Glomus sp., Paraglomus occultum, Paraglomus brasilianum, and Scutellospora heterogama. Relative abundance of spores of A. trappei were increased with increase of cultivation period of the ginseng. However, relative abundance of other species of AMF and Shannon diversity (H') of AMF were significantly decreased with the increase of cultivation periods of the ginseng.

• Journal of Life Science
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• v.16 no.6
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• pp.994-1000
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• 2006

Stevia rebaudiana Bertoni is a sweet herb of the Asteraceae family originally derived from South America. Twenty three bacterial strains and ten yeast strains were isolated from fermented Stevia extract and identified by general taxonomic methods and molecular genetic method. Isolated strains from fermented Stevia extract include ten species of bacteria which belong to five genus and one species of yeast. Based on 16S and 18S rDNA sequence analysis, phylogenetic trees were constructed. Antimicrobial activity of the isolated strains was examined against various bacteria and plant-pathogenic fungi. Among them, Lactobacillus paracasei SB13 showed strong antibacterial activity towards a wide range of bacteria. These results may be useful to develop environmentally friendly microbial agent for soil improvement.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.464-476
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• 2022

In recent years, macroalgal bloom occurs frequently in coastal oceans worldwide. It might be attributed to accelerating climate change. "Green tide" events caused by proliferation of green macroalgae (Ulva spp.) not only damage the local economy, but also harm coastal environments. These nuisance events have become common across several coastal regions of continents. In Korea, green tide incidences are readily seen throughout the year along the coastlines of Jeju Island, particularly the northeastern coast, since the 2000s. Ulva species are notorious to be difficult for morphology-based species identification due to their high degrees of phenotypic plasticity. In this study, to investigate temporal variation in Ulva community structure on Jeju Island between 2015 and 2020, chloroplast barcode tufA gene was sequenced and phylogenetically analyzed for 152 specimens from 24 sites. We found that Ulva ohnoi and Ulva pertusa known to be originated from subtropical regions were the most predominant all year round, suggesting that these two species contributed the most to local green tides in this region. While U. pertusa was relatively stable in frequency during 2015 to 2020, U. ohnoi increased 16% in frequency in 2020 (36.84%), which might be associated with rising sea surface temperature from which U. ohnoi could benefit. Two species (Ulva flexuosa, Ulva procera) of origins of Europe should be continuously monitored. The findings of this study provide valuable information and molecular genetic data of genus Ulva occurring in southern coasts of Korea, which will help mitigate negative influences of green tide events on Korea coast.

• Journal of fish pathology
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• v.30 no.2
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• pp.79-88
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• 2017

At the present, fish farms are suffering a lot of economic losses due to infectious diseases caused by various pathogens including aeromonad. Aeromonad is ubiquitous bacteria that causes infectious diseases. At least 26 species in the genus Aeromonas have been reported to cause fatal infections not only in salmonid fishes, but also in other freshwater and seawater fishes. Molecular techniques based on nucleic acid sequences of 16S rDNA and housekeeping genes can be used to identify the Aeromonas species. In this study, The genus Aeromonas was isolated from salmonid fishes of sixteen fish farms in Gangwon-Do, Korea and phylogenetically identified based on the sequences of 16S rDNA and housekeeping genes for Aeromonad, i.e. RNA polymerase sigma factor ${\sigma}^{70}$ (rpoD) or DNA gyrase subunit B (gyrB). Consequently, 96 strains were collected from Atlantic salmon (Salmo salar), coho salmon (Oncorhynchus kisutch), masou salmon (Oncorhynchus masou) and rainbow trout (Oncorhynchus mykiss), and 36 isolates were identified as the genus Aeromonas by 16S rDNA analysis. Thirty six Aeromonad isolates were further analysed based on rpoD or gyrB gene sequences and found Aeromonas salmonicida (24 isolates), A. sobria (10 isolates), A. media (1 isolates) and A. popoffii (1 isolates), indicating that A. salmonicida is a main infectious bacteria in Salmonid fishes in Gangwon-Do. It was also proved that the phylogenetic identification of Aeromonas species based on the sequences of housekeeping gene is more precise than the 16S rDNA sequence.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.454-459
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• 2013

Beet armyworm, Spodoptera exigua is difficult to control using chemical insecticides because of the fast development of insecticide resistance. For eco-friendly beet armyworm managements, various control agents are required. Entomopathogenic fungus is one of the promise control agents as an alternative to chemical control agent. We isolated entomopathogenic fungi from soil samples of Yangpyeong, Gyeonggi-do by insect-bait method using Tenebio molitor and conducted bioassay to larva of beet armyworm. The result of bioassay, a selected strain FT83 showed 100% mortality against third instar larva of S. exigua. On the basis of morphological characteristics and analysis of 18srRNA sequence for ITS, the strain FT83 was identified as a Metarhizium anisopliae. The mortality of beet armyworm showed $81.6{\pm}9.3%$ at $1{\times}10^6$ conidia/ml, 100% at $1{\times}10^7$ conidia/ml and 100% at $1{\times}10^8$ conidia/ml respectively. Therefore, we recommend to proper control efficacy against S. exigua in which more than $1{\times}10^7$ conidia/ml suspension of M. anisopliae FT83.