• Food Science and Biotechnology
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• v.14 no.5
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• pp.581-585
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• 2005

The antimicrobial activity of partially purified enterocin K25, produced by Enterococcus sp. K25, was abolished by proteases such as pepsin and proteinase K. The bacteriocin was resistant to heat treatment at $75^{\circ}C$ for 15 min and lost 75% of its activity at $100^{\circ}C$ for 30 min. Enterocin K25 showed bactericidal mode of action against an indicator strain, Lactobacillus plantarum NCDO 955. Enterocin K25 was purified to 112.6-fold purity via conventional steps of ammonium sulfate precipitation, ion exchange chromatography, and reversed phase high performance liquid chromatography (RP-HPLC). The molecular mass of the purified enterocin K25 was estimated as 4.3 kDa on an electrophoresis gel. Plasmid (${\sim}6.5\;kb$) linkage of production of enterocin K25 was confirmed by plasmid curing.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.10a
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• pp.172-172
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• 2003

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.329.2-329
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• 1998

No Abstract, See Full Text

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2004.10a
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• pp.93-93
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• 2004

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.326-330
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• 1996

To illustrate whether a hemolysin in $\delta$-endotoxins of Bacillus thuringiensis strain 73E10-2 and subsp. israelensis had immunological identity, a cyt gene of the strain 73E10-2 which encodes a hemolysin was cloned to B. subtilis (transformant 2753). The transformant 2753 containing cyt gene produced the hemolysin which lysed sheep erythrocytes after treatment of proteinase K. The hemolysin was proved also to be toxic against mosquito larvae (Aedes aegypti). The molecular weight of the hemolysin produced from the transformant 2753 was determined to be about 25 kDa by SDS-PAGE and immunoblot. The hemolysin in $\delta$-endotoxin of subsp. israelensis and subsp. kyushensis did not react on immunoblot using polyclonal anti-$\delta$-endotoxin of the strain 73E10-2, but 70-140 kDa mosquitocidal toxins in $\delta$-endotoxin of subsp. kyushuensis reacted.

• Parasites, Hosts and Diseases
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• v.45 no.4
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• pp.283-285
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• 2007

To examine the expressed gene profile during encystation of Acanthamoeba castellanii Castellani, we used differentially expressed gene (DGE) screening by RT-PCR with 20 sets of random primers. From this analysis, we found that approximately 16 genes showed up regulation during encystation. We chose 6 genes, which had relatively higher expression levels, for further investigation. Based on homology search in database, DEG2 showed 55% of similarity with xylose isomerase, DEG9 showed 37% of similarity with Na P-type ATPase, and DEG14 showed 77% of similarity with subtilisin-like serine proteinase. DEG3 and DEG26 were identified as hypothetical proteins and DEG25 exhibited no significant similarity to any known protein. Encystation of Acanthamoeba has been suggested to be a process to resist adverse environmental or nutritional conditions. Further characterization studies of these genes may provide us with more information on the encystation mechanism of Acanthamoeba.

• Journal of Microbiology
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• v.33 no.4
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• pp.283-288
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• 1995

We have identified hemolysin rendering virulency of Vibrio anguilarum grown at 23.deg.C which was evaluated on human RBCs. Hemolysin itself was separated as a single band on non-denaturing gel electrophoresis. Vibrio hemolysin was destroyed by trypsin and proteinase K and was heat labile. Optimal pH for activity was around pH 6 while pI of the molecule was recognized as 5.7, with relative distance (R$\sub$f/) on non-denaturing gel was 0.7. Addition of EDTA and FeCI$\sub$3/ drew the possibility that the production of hemolysin was mainly induced to overcome iron deficiency inside host animalsd infection.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.74-80
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• 2011

Bacteriocin-producing lactic acid bacterium having antagonistic activity against Bacillus cereus, was isolated from Kimchi. The selected strain was identified as Lactococcus lactis by the Bergey's manual and 16S rDNA analysis, and named as L. lactis ET45. The bacteriocin was stable in the pH range 3.0-11.0. The bacteriocin was active over a wide temperature range from $40^{\circ}C$ to $121^{\circ}C$. Optimal culture condition for producing bacteriocin was obtained by growing the cells on MRS medium at pH 7.5 and $30^{\circ}C$ for 18 h. Antibacterial activity of the bacteriocin was completely disappeared by proteinase K, and this means that bacteriocin is a proteinous substance. The molecular weight of bacteriocin was estimated to be about 4.5 kDa by tricine sodium dodecyl sulfate polyacryamide gel electrophoresis (TSDS-PAGE).

• Biomedical Science Letters
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• v.3 no.2
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• pp.89-94
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• 1997

The authors characterized the proteins of the crude antigen obtained from Clonorchis sinensis worm and excretory-secretory and billis from rabbits, experimentally infected for 3 months. Protein composition was observed after adding a cysteine proteinase inhibitor E-64 and a serine proteinase inhibitor PMSF, respectively. SDS-PAGE of the crude antigen from C. sinensis recovered from the infected rabbits, the crude antigen from the adult worm excretory-secretory, and the crude antigen from billis of the rabbits resolved 26, 27 and 19 profiles between 200-9 kDa, respectively. When E-64 supplemented 29, and 22 bands, respectively. More study should be carried out in the future on the immunological characteristics and the monoclonal antibody of the each antigen.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.151-158
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• 2007

Among 68 strains of lactic acid bacteria (LAB) isolated from Dongchimi, a strain K11 was selected due to its bactericidal activity against Escherichia coli O157 The strain K11 was identified as Lactobacillus plantarum, based on physiological and biochemical characteristics. In the late exponential phase, La. plantarum K11 showed maximum bacteriocin activity (12,800 BU/mL) and maintained until the early stationary phase. The bacteriocin activity was completely inactivated by all the proteolytic enzymes such as pepsin, protease, proteinase K, papain, chymotrypsin, and trypsin, but the activity was not affected by catalase, a-amylase, lysozyme, and lipase, suggesting proteinaceous nature of the bacteriocin. Additionally, this activity was not affected in the pH range from 3.0 to 9.0 and under storage conditions like 30 days at -20,4, or $25^{\circ}C$. Although the bacteriocin activity was absolutely lost after 15 min treatment at 121, it was relatively stable at $70^{\circ}C$ for 60 min or $100^{\circ}C$ for 30 min. The activity was disappeared by treatment with acetone, benzene, ethanol, or methanol, but it was not affected by treatment with chloroform or hexane. The antibacterial activity of the bacteriocin was good against some LAB including Lactobacillus spp., Enterococcus spp., and Streptococcus spp., but not against food-borne pathogens such as Bacillus spp., Listeria spp., and Staphylococcus spp. as well as yeasts and molds. Especially, some intestinal bacteria such as Enterobacter aerogenes and E. coli were significantly affected by the bacteriocin of La, plantarum K11. Furthermore, the addition of 640 BU/mL resulted in the complete clearance of E. coli O157 after 10 hr.