• Journal of Veterinary Science
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• v.25 no.4
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• pp.54.1-54.16
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• 2024

Importance: As one of the main etiologic agents of infectious diseases in pigs, pseudorabies virus (PRV) infections have caused enormous economic losses worldwide. EP0, one of the PRV early proteins (EP) plays a vital role in PRV infections, but the mechanisms are unclear. Objective: This study examined the function of EP0 to provide a direction for its in-depth analysis. Methods: In this study, the EP0-deleted PRV mutant was obtained, and Tandem Mass Tag-based proteomic analysis was used to screen the differentially expressed proteins (DEPs) quantitatively in EP0-deleted PRV- or wild-type PRV-infected porcine kidney 15 cells. Results: This study identified 7,391 DEPs, including 120 and 21 up-regulated and down-regulated DEPs, respectively. Western blot analysis confirmed the changes in the expression of the selected proteins, such as speckled protein 100. Comprehensive analysis revealed 141 DEPs involved in various biological processes and molecular functions, such as transcription regulator activity, biological regulation, and localization. Conclusions and Relevance: These results holistically outlined the functions of EP0 during a PRV infection and might provide a direction for more detailed function studies of EP0 and the stimulation of lytic PRV infections.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.260-268
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• 2016

The aim of this work was to investigate the cellular responses and proteomic analysis of Bacillus cereus MH-2 exposed to EGCG. Strain MH-2 was isolated from commercial Ssamjang and has the hemolytic activity. Survival of the MH-2 strain with time in the presence of different concentrations of EGCG under sublethal conditions was monitored. The amount of alginate from MH-2 strain decreased depending on the increasing concentrations of EGCG and increased depending on the exposure time at any particular EGCG concentration. Analysis of SDS-PAGE and Western blot using anti-DnaK and anti-GroEL revealed that two stress shock proteins, 70 kDa DnaK and 60 kDa GroEL were found to decrease in proportion to the EGCG concentration in exponentially growing cultures. Scanning electron microscopic analysis demonstrated the presence of protrusions and fused rod forms on the cells treated with EGCG. 2-DE of soluble protein fractions from MH-2 cultures showed 20 protein spots changed by EGCG exposure. These proteins involved in enterotoxins (hemolysin BL lytic component L1 and hemolysin BL-binding protein), chaperons (DnaK and GroEL), cell defense (peptidase M4 family proteins), and various biosynthesis and energy metabolism were identified by peptide mass fingerprinting using MALDI-TOF. These results provide clues for understanding the mechanism of EGCG-induced stress and cytotoxicity on B. cereus MH-2.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.216-221
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• 2003

Various physico-chemical and biological methods have been used to remove. cyanobacteria which causes blooms and releases toxin. The purpose of the following experiment is aimed finding out which cyanobacteria are affected by $_L-lysine $ and what concentration of$_L-lysine $ inhibits cyanobacteria. The 20 samples of Microcystis sp. have been tested. To prove the growth inhibition on Microcystis sp., double-layered agar method and microplate method have been used. When the concentration of $_L-lysine $ is as heavy as 100 ${\mu}g\; ml^{-1}$~300 ${\mu}g\; ml^{-1}$, some Microcystis sp. have made halo zone. Some Microcystis sp. have shown so high activity as to be inhibited in their growth by the $_{L}$-lysine of concentration 10 ${\mu}g\; ml^{-1}$ with microplate method. These activities are various in accordance with every species. In additions, the microplate method has been proven to be an easy way which examine the lytic activity on the species of algae.e.

• BMB Reports
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• v.36 no.6
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• pp.586-592
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• 2003

Four putative promoters of the temperate mycobacteriophage L1 were cloned by detecting the $\beta$-galactosidase reporter expression in E. coli transformants that carried L1 specific operon-fusion library. All of the four L1 promoters were also found to express differentially in the homologous environment of mycobacteria. Of the four promoters, two were suggested to be the putative early promoters of L1 since they express within 0 to 10 min of the initiation of the lytic growth of L1. One of the putative early promoters showed a relatively better and almost identical activity in both E. coli and M. smegmatis. By a sequence analysis, we suggest that the L1 insert that contained the stronger early promoter possibly carries two convergent E. coli $\sigma^{70}$-like L1 promoters, which are separated from each other by about 300 nucleotides. One of them is the early promoter of L1 as it showed a 100% similarity with the early $P_{left}$ promoter of the homoimmune phage L5. The second promoter, designated P4, was suggested for its appreciable level of reporter activity in the absence of the -10 element of the $P_{left}$ equivalent of L1. By analyzing most of the best characterized mycobacteriophages-specific promoters, including the L1 promoter P4, we suggest that both the -10 and -35 hexamers of the mycobacteriophage promoters are highly conserved and almost similar to the consensus -10 and -35 hexamers of the E. coli $\sigma^{70}$ promoters.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.199-205
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• 1999

Vibrio vulnificus cytolysin caused platelet cytolysis and increased intracellular calcium concentration $([Ca^{2+}]_i)$ of rat platelets in a concentration-dependent manner. In the presence of V. vulnificus cytolysin (3 HU/ml), lactate dehydrogenase (LDH) activity was increased from $1.3{\pm}0.4%$ of control to $64.3{\pm}3.4%$ in platelet suspension buffer. In $Ca^{2+}-free$ platelet suspension buffer, however, V. vulnificus cytolysin did not induce $[Ca^{2+}]_i$ increase and LDH release. Addition of EGTA (2 mM) to suspension buffer after the initial $Ca^{2+}$ influx reversed $[Ca^{2+}]_i$ to the control level. However, a $Ca^{2+}$ channel blocker verapamil $(20\;{\mu}M)$ or mefenamic acid $(20\;{\mu}M)$ did not inhibit V. vulnificus cytolysin-induced $[Ca^{2+}]_i$ increase and LDH release. Divalent cations such as $Co^{2+},\;Cd^{2+}\;or\;Mn^{2+}$ (2 mM each) also did not alter V. vulnificus cytolysin-induced $[Ca^{2+}]_i$ increase and LDH release. V. vulnificus cytolysin (3 HU/ml)-induced calcium influx was completely blocked by lanthanum (2 mM). Lanthanum (2 mM) also completely blocked V. vulnificus cytolysin (3 HU/ml)-induced LDH release. Osmotic protectants such as, raffinose, sucrose or PEG600 (50 mM each) did not inhibit the lytic activity of V. vulnificus cytolysin. In conclusion, lanthanum sensitive $Ca^{2+}$ influx plays a significant role in Vibrio vulnificus cytolysin-induced platelet cytolysis and thrombocytopenia in V. vulnificus infection.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.385-393
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• 2016

Pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. Owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. Bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. In this study, we isolated bacteriophages against P. syringae pv. actinidiae from soils collected from kiwifruit orchards in Korea and selected seven bacteriophages for further characterization based on restriction enzyme digestion patterns of genomic DNA. Among the studied bacteriophages, two belong to the Myoviridae family and three belong to the Podoviridae family, based on morphology observed by transmission electron microscopy. The host range of the selected bacteriophages was confirmed using 18 strains of P. syringae pv. actinidiae, including the Psa2 and Psa3 groups, and some were also effective against other P. syringae pathovars. Lytic activity of the selected bacteriophages was sustained in vitro until 80 h, and their activity remained stable up to 50℃, at pH 11, and under UV-B light. These results indicate that the isolated bacteriophages are specific to P. syringae species and are resistant to various environmental factors, implying their potential use in control of bacterial canker disease in kiwifruits.

• The Korean Journal of Mycology
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• v.40 no.1
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• pp.44-48
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• 2012

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herb in Korea. However, yield losses reached up to 30~60 % due to various diseases during 3 or 5 years of ginseng cultivation. Therefore, successful production of ginseng roots depends primarily on the control of diseases. The objective of this study is to select potential multifunctional biocontrol agents from actinomycetes for the control of multiple ginseng diseases as an alternative to fungicides. Ninety three Streptomyces strains were selected and their ability to produce antibiotics, siderophore and lytic enzymes such as protease and cellulose were investigated. Eight of the isolates, strains A75, A501, 515, 523, A704, A1444, A3265 and A3283 produced cellulase and protease. These strains also produced siderophore and showed potent antifungal activity against Botrytis cinerea, Cylindrocarpon destructans, Collectotricum gloeosporioides, Phytophthora capsici and Rhizoctonia solani causing ginseng root rot.

• Molecules and Cells
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• v.42 no.1
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• pp.79-86
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• 2019

Endolysins are bacteriophage-derived enzymes that hydrolyze the peptidoglycan of host bacteria. Endolysins are considered to be promising tools for the control of pathogenic bacteria. LysB4 is an endolysin produced by Bacillus cereus-infecting bacteriophage B4, and consists of an N-terminal enzymatic active domain (EAD) and a C-terminal cell wall binding domain (CBD). LysB4 was discovered for the first time as an L-alanoyl-D-glutamate endopeptidase with the ability to breakdown the peptidoglycan among B. cereus-infecting phages. To understand the activity of LysB4 at the molecular level, this study determined the X-ray crystal structure of the LysB4 EAD, using the full-length LysB4 endolysin. The LysB4 EAD has an active site that is typical of LAS-type enzymes, where $Zn^{2+}$ is tetrahedrally coordinated by three amino acid residues and one water molecule. Mutational studies identified essential residues that are involved in lytic activity. Based on the structural and biochemical information about LysB4, we suggest a ligand-docking model and a putative endopeptidase mechanism for the LysB4 EAD. These suggestions add insight into the molecular mechanism of the endolysin LysB4 in B. cereus-infecting phages.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.380-387
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• 2016

This study was performed to select potentially available biological control agent from soil bacteria for prevention of ginseng damping off. More than five hundred strains were isolated from ginseng rhizosphere soil. By testing antifungal activity, we have selected three soil bacteria strains and their ability to produce antibiotics and lytic enzymes such as cellulase, protease and pectate lyase was examined. Also, the presence of genes for biosynthesis of lipopeptide such as fengycin, bacillomycin D, surfactin, iturin A, and zwittermicin A was investigated in selected strains. All three strains produced cellulase, protease, and xylanase. Moreover, these strains had gene for biosynthesis of bacillomycin D, surfactin, and iturin A. ES1 and ES3 strains were identified Bacillus methylotrophucus and ES2 was confirmed Bacillus amyloliquefaciens using phylogenetic analysis on the basis of 16S rRNA gene sequences. In field test, control value of ES1, ES2 and ES3 treatment was 32.4%, 46.8% and 36.7%, respectively. This results indicate that antagonistic microbes with high ability of antifungal and lytic enzyme activity can be used as a useful biological control agent to control ginseng damping off.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.659-666
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• 2010

Lysobacter antibioticus HS124 was isolated from rhizosphere soil in previous experiments, which produced lytic enzymes such as chitinase, gelatinase, lipase and protease. In addition, HS124 released an antibiotic compound, 4-hydroxyphenylacetic acid (4-HPAA). When larvae of P. xylostella was treated with HS124 culture broth, its body was destroyed, and degraded with the increase of incubation time, yielding glycine which was detected from HS124 culture broth. When 4-HPAA produced from HS124 was sprayed, larvae mortality increased with increasing concentration of 4-HPAA. When HS124 culture supplemented with Tween 80 was sprayed, its insecticidal activity against larvae was approximately 1.4 times higher compared to the culture without Tween 80. Insecticide (IS), HS124 culture broth (HS124), Magic-pi (MP) and HS124 culture broth+Magic-pi (HS124+MP) were each treated against larvae of P. xylostella to investigate their insecticidal effect where sterile diluted water (SDW) was used as a control. The highest mortality of larvae was found in HS124+MP, followed by IS, MP, HS124 and SDW respectively. Mortality of larvae in HS124 was 31% higher than that in SDW, but 41% lower than that in HS124+MP, meaning that both enzymes and antibiotics produced from HS124 may synergistically act as active agents with plant extract containing neem oil and turmeric in HS124+MP treatment. These results suggested that L. antibioticus HS124 together with plant extract can be one of candidates for biocontrol agents against Plutella xylostella.