• Journal of Veterinary Science
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• v.23 no.5
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• pp.67.1-67.11
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• 2022

Background: Budgerigar fledgling disease polyomavirus (BFDV) is the pathogen that causes budgerigar fledgling disease in psittacine species. The clinical signs of PBFV infection include ascites, hepatitis, and crop stasis. BFDV is associated with a high mortality rate in nestling birds. In contrast, adult birds only have mild symptoms such as feather dystrophy. Objectives: This study aimed to determine the prevalence, genetic characteristics, and phylogenetic analysis of BFDV in pet parrots in Korea. Methods: Fecal and tissue samples were collected from 217 pet parrots from 10 veterinary hospitals including Chungbuk National University Veterinary Hospital. The molecular screening was performed using polymerase chain reaction (PCR) analysis of the small t/large T antigen gene segment. Full-length genome sequencing with the Sanger and phylogenetic analysis were performed on BFDV-positive samples. Results: The PCR results based on the small t/large T antigen gene marker indicated that BFDV DNA was present in 10 out of 217 screened samples. A whole-genome sequence was obtained from six strains and phylogenetic analysis revealed no significant relationship existed between the species and geographical locations amongst them. Conclusions: The prevalence of BFDV infection in South Korea is not high when compared to the prevalence of BFDV in other parts of the world, however, it has been reported sporadically in various species and geographic locations. The whole-genome analysis revealed 0.2%-0.3% variation in intragenomic homogeneity among the six strains analyzed. Korean strains are separately on the phylogenetic tree from their counterparts from China and Japan which might reflect the substantial genetic variation.

• The Plant Pathology Journal
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• v.28 no.1
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• pp.68-74
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• 2012

Biocontrol microbes have mainly been screened among large collections of microorganisms $via.$ nutrient-rich $in$ $vitro$ assays to identify novel and effective isolates. However, thus far, isolates from only a few genera, mainly spore-forming bacilli, have been commercially developed. In order to isolate field-effective biocontrol microbes, we screened for more than 200 oligotrophic bacterial strains, isolated from rhizospheres of various soil samples in Korea, which induced systemic resistance against the soft-rot disease caused by $Pectobacterium$ $carotovorum$ SCC1; we subsequently conducted in $planta$ bioassay screening. Two oligotrophic bacterial strains were selected for induced systemic disease resistance against the $Tobacco$ $Mosaic$ $Virus$ and the gray mold disease caused by $Botrytis$ $cinerea$. The oligotrophic bacterial strains were identified as $Pseudomonas$ $manteilii$ B001 and $Bacillus$ $cereus$ C003 by biochemical analysis and the phylogenetic analysis of the 16S rRNA sequence. These bacterial strains did not exhibit any antifungal activities against plant pathogenic fungi but evidenced several other beneficial biocontrol traits, including phosphate solubilization and gelatin utilization. Collectively, our results indicate that the isolated oligotrophic bacterial strains possessing induced systemic disease resistance could provide useful tools as effective biopesticides and might be successfully used as cost-effective and preventive biocontrol agents in the field.

• The Plant Pathology Journal
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• v.31 no.2
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• pp.165-175
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• 2015

Anthracnose is a fungal disease caused by Colletotrichum species that is detrimental to numerous plant species. Anthracnose control with fungicides has both human health and environmental safety implications. Despite increasing public concerns, fungicide use will continue in the absence of viable alternatives. There have been relatively less efforts to search antagonistic bacteria from mudflats harboring microbial diversity. A total of 420 bacterial strains were isolated from mudflats near the western sea of South Korea. Five bacterial strains, LB01, LB14, HM03, HM17, and LB15, were characterized as having antifungal properties in the presence of C. acutatum and C. gloeosporioides. The three Bacillus atrophaeus strains, LB14, HM03, and HM17, produced large quantities of chitinase and protease enzymes, whereas the B. amyloliquefaciens strain LB01 produced protease and cellulase enzymes. Two important antagonistic traits, siderophore production and solubilization of insoluble phosphate, were observed in the three B. atrophaeus strains. Analyses of disease suppression revealed that LB14 was most effective for suppressing the incidence of anthracnose symptoms on pepper fruits. LB14 produced antagonistic compounds and suppressed conidial germination of C. acutatum and C. gloeosporioides. The results from the present study will provide a basis for developing a reliable alternative to fungicides for anthracnose control.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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• pp.1891-1907
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• 2016

Yeasts that are present in marine environments have evolved to survive hostile environments that are characterized by high exogenous salt content, high concentrations of inhibitory compounds, and low soluble carbon and nitrogen levels. Therefore, yeasts isolated from marine environments could have interesting characteristics for industrial applications. However, the application of marine yeast in research or industry is currently very limited owing to the lack of a suitable isolation method. Current methods for isolation suffer from fungal interference and/or low number of yeast isolates. In this paper, an efficient and non-laborious isolation method has been developed and successfully isolated large numbers of yeasts without bacterial or fungal growth. The new method includes a three-cycle enrichment step followed by an isolation step and a confirmation step. Using this method, 116 marine yeast strains were isolated from 14 marine samples collected in the UK, Egypt, and the USA. These strains were further evaluated for the utilization of fermentable sugars (glucose, xylose, mannitol, and galactose) using a phenotypic microarray assay. Seventeen strains with higher sugar utilization capacity than the reference terrestrial yeast Saccharomyces cerevisiae NCYC 2592 were selected for identification by sequencing of the ITS and D1/D2 domains. These strains belonged to six species: S. cerevisiae, Candida tropicalis, Candida viswanathii, Wickerhamomyces anomalus, Candida glabrata, and Pichia kudriavzevii. The ability of these strains for improved sugar utilization using seawater-based media was confirmed and, therefore, they could potentially be utilized in fermentations using marine biomass in seawater media, particularly for the production of bioethanol and other biochemical products.

• BMB Reports
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• v.29 no.6
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• pp.569-573
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• 1996

Clinical strains of Mycobacterium tuberculosis, M. terrae complex, M. gordonae, M. avium-intracellulae complex, and M. fortuitum from Korean patients were isolated and analyzed by comparing large restriction fragment (LRF) patterns produced by digestion of genomic DNA with infrequent-cutting endonucleases like AsnI and XbaI. and pulsed-field gel electrophoresis (PFGE). Three M. tuberculosis, two M. terrae complex, two M. gordonae, two M. avium-intracellulae complex, and two M. fortuitum strains were compared by using AsnI and XbaI. and this allowed easy visual separation of all epidemiologically unrelated strains. PFGE exhibits different DNA restriction patterns which are easy to compare. Genome size of the strains roughly ranged from 3020 to 3335 kb. The LRF patterns are useful for epidemiologic studies of tuberculosis with regard to drug resistance.

• Journal of Veterinary Science
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• v.21 no.3
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• pp.43.1-43.13
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• 2020

Background: Canine parvovirus (CPV) and feline panleukopenia (FPV) cause severe intestinal disease and leukopenia. Objectives: In Korea, there have been a few studies on Korean FPV and CPV-2 strains. We attempted to investigate several genetic properties of FPV and CPV-2. Methods: Several FPV and CPV sequences from around world were analyzed by Bayesian phylo-geographical analysis. Results: The parvoviruses strains were newly classified into FPV, CPV 2-I, CPV 2-II, and CPV 2-III genotypes. In the strains isolated in this study, Gigucheon, Rara and Jun belong to the FPV, while Rachi strain belong to CPV 2-III. With respect to CPV type 2, the new genotypes are inconsistent with the previous genotype classifications (CPV-2a, -2b, and -2c). The root of CPV-I strains were inferred to be originated from a USA strain, while the CPV-II and III were derived from Italy strains that originated in the USA. Based on VP2 protein analysis, CPV 2-I included CPV-2a-like isolates only, as differentiated by the change in residue S297A/N. Almost CPV-2a isolates were classified into CPV 2-III, and a large portion of CPV-2c isolates was classified into CPV 2-II. Two residue substitutions F267Y and Y324I of the VP2 protein were characterized in the isolates of CPV 2-III only. Conclusions: We provided an updated insight on FPV and CPV-2 genotypes by molecular-based and our findings demonstrate the genetic characterization according to the new genotypes.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.654-662
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• 2024

To investigate the effect of the predominant fungal species from Korean traditional meju and doenjang on soybean fermentation, the enzymatic activity and amino acid production of twenty-two fungal strains were assessed through solid- and liquid-state soybean fermentation. Enzymatic activity analyses of solid-state fermented soybeans revealed different enzyme activities involving protease, leucine aminopeptidase (LAP), carboxypeptidase (CaP), glutaminase, γ-glutamyl transferase (GGT), and amylase, depending on the fungal species. These enzymatic activities significantly affected the amino acid profile throughout liquid-state fermentation. Strains belonging to Mucoromycota, including Lichtheimia, Mucor, Rhizomucor, and Rhizopus, produced smaller amounts of total amino acids and umami-producing amino acids, such as glutamic acid and aspartic acid, than strains belonging to Aspergillus subgenus circumdati. The genera Penicillium and Scopulariopsis produced large amounts of total amino acids and glutamic acid, suggesting that these genera play an essential role in producing umami and kokumi tastes in fermented soybean products. Strains belonging to Aspergillus subgenus circumdati, including A. oryzae, showed the highest amino acid content, including glutamic acid, suggesting the potential benefits of A. oryzae as a starter for soybean fermentation. This study showed the potential of traditional meju strains as starters for soybean fermentation. However, further analysis of processes such as the production of G-peptide for kokumi taste and volatile compounds for flavor and safety is needed.

• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.838-845
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• 2024

Excessive alcohol consumption can have serious negative consequences on health, including addiction, liver damage, and other long-term effects. The causes of hangovers include dehydration, alcohol and alcohol metabolite toxicity, and nutrient deficiency due to absorption disorders. Additionally, alcohol consumption can slow reaction times, making it more difficult to rapidly respond to situations that require quick thinking. Exposure to a large amount of ethanol can also negatively affect a person's righting reflex and balance. In this study, we evaluated the potential of lactic acid bacteria (LAB) to alleviate alcohol-induced effects and behavioral responses. Two LAB strains isolated from kimchi, Levilactobacillus brevis WiKim0168 and Leuconostoc mesenteroides WiKim0172, were selected for their ethanol tolerance and potential to alleviate hangover symptoms. Enzyme activity assays for alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) were then conducted to evaluate the role of these bacteria in alcohol metabolism. Through in vitro and in vivo studies, these strains were assessed for their ability to reduce blood alcohol concentrations and protect against alcohol-induced liver damage. The results indicated that these LAB strains possess significant ethanol tolerance and elevate ADH and ALDH activities. LAB administration remarkably reduced blood alcohol levels in rats after excessive alcohol consumption. Moreover, the LAB strains showed hepatoprotective effects and enhanced behavioral outcomes, highlighting their potential as probiotics for counteracting the adverse effects of alcohol consumption. These findings support the development of functional foods incorporating LAB strains that can mediate behavioral improvements following alcohol intake.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.54-63
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• 2015

Streptomyces spp. isolated from turfgrass rhizosphere and tested for their response to large-patch control fungicides. The tested fungicides were actually used in golf course or turfgrass cultivation to prevent large-patch disease. Tolerance to 3 triazole group of the strains was the highest to the PR fungicide, and following the SR fungicide, whereas the isolated strains were no tolerance to HR fungicide. Tolerances to three kind of Strobilurin group were similar for the all of the tested Streptomyces spp.. Growth and sporulation of the all strain was normal in CB and AP fungicide treatments. However no spore formulated in double concentration. Strains, tolerance to acetanilide fungicides, appeared that KT fungicide tolerance was higher than MK fungicide. The selected strains showed strong tolerance against AT fungicide but have no tolerance to ATR fungicides. In conclusion, the bacterial strains showed tolerance against 1 carbamate, 1 organophosphate and 1 cyanopyrrole group, while have no tolerance against two mixture formulations (1 Quinone + Strobilurin and 1 Imidazole + Triazole).

• Earthquakes and Structures
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• v.19 no.3
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• pp.189-196
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• 2020

The near-collapse performance limit is defined as the deformation at the 20% drop of maximum base shear in the decreasing region of the pushover curve for ductile framed buildings. Although monotonic pushover analysis is preferred due to the simple application procedure, this analysis gives rise to overestimated results by neglecting the cumulative damage effects. In the present study, the acceptabilities of monotonic and cyclic pushover analysis results for the near-collapse performance limit state are determined by comparing with Incremental Dynamic Analysis (IDA) results for a 5-story Reinforced Concrete framed building. IDA is performed to obtain the collapse point, and the near-collapse drift ratios for monotonic and cyclic pushover analysis methods are obtained separately. These two alternative drift ratios are compared with the collapse drift ratio. The correlations of the maximum tensile and compression strain at the base columns and beam plastic rotations with interstory drift ratios are acquired using the nonlinear time history analysis results by the simple linear regression analyses. It is seen that these parameters are highly correlated with the interstory drift ratios, and the results reveal that the near-collapse point acquired by monotonic pushover analysis causes unacceptably high tensile and compression strains at the base columns, as well as large plastic rotations at the beams. However, it is shown that the results of cyclic pushover analysis are acceptable for the near-collapse performance limit state.