• 한국미생물·생명공학회지
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• 제19권2호
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• pp.116-121
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• 1991

A bacterial strain KN, which highly produced a protease, was isolated from several soil samples and identified to to belong to the genus Bacillus. We selected mutant strain Bacillus sp. KN103N, which was hyperproducer of protease and was resistant to D-cyclowerine, from the strain KN by several steps of mutagenesis. Neutral protease productivity of mutant strain KN103N was about 55 times as much as that of the original strain KN. The optimum pH and temperature for the enzyme activity were 7.0 and 50$^{\circ}C$, respectively and the enzyme was relatively stable at pH6.0~8.0 and below 40$^{\circ}C$. The enzyme was inactivated by EDTA, but not by DFP. These results indicate that the enzyme from Bacillus sp. KN103N was a neutral (metallo-) protease.

• BMB Reports
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• 제28권5호
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• pp.443-450
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• 1995

Cloned staphylococcal peptidoglycan hydrolase was used in determining the physiological characteristics of peptidoglycan hydrolase. This enzyme hydrolyzed the bacterial cell walls and released the N-terminal alanine, but not the reducing groups. This cloned gene product was localized in the cytoplasm of transformed Escherichia coli. Activity gels indicated the enzyme had an Mr of about 54,000, which was consistent with the deduced Mr from sequencing of the cloned gene. The activity bound to CM-cellulose but not DEAE-cellulose resin, indicating it as a basic protein. Enhanced enzyme activity in a low concentration of cations, and inhibited enzyme activity in a solution with dissolved phospholipids, suggested that the activity and the availability of this basic protein may be regulated between negatively charged and positively charged cellular molecules. The activity against boiled crude cell wall was much greater than against purifed cell wall, suggesting protein associated with crude cell wall may aid in the binding of the peptidoglycan hydrolase The cloned peptidoglycan hydrolase showed positive activity on whole cells of some lysostaphin-resistant coagulase-negative staphylococci. The cloned enzyme may be an alternative for lysostaphin for lysis of staphylococci.

• 한국치위생학회지
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• 제1권2호
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• pp.243-250
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• 2001

To evaluate the effect of disinfectants for Alginate impression, several commercially available disinfectants were tested to Alginate model contaminated by Methicillin resistant Staphylococcus aureus. Alginate specimens were artificially contaminated by Staphylococcus aureus and soaking in four commercially available disinfectants for 1, 5, 10 minutes and colonies were counted for each case. Significant reduction of bacterial colony counts was noted after soaking in 0.5% and 0.05% sodium hypochlorite and after soaking in 2% glutaraldehyde, but not after soaking in Hypochlorus add. Commercially available sodium hypochlorite and glutaraldehyde were found to be effective disinfectants for Alginate impression. But hypochlorus add was not adequate disinfectant.

• Journal of Dairy Science and Biotechnology
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• 제27권2호
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• pp.43-48
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• 2009

Listeria monocytogenes is a major concern in food processing environments because it is ubiquitous and can easily contaminate food during processing. Contaminated food and the surfaces in food facilities can serve as reservoirs of L. monocytogenes, which can lead to the serious foodborne illness listeriosis in consumers. L. monocytogenes can adhere to materials commonly used in food processing equipment and form biofilms. In the biofilm mode, L. monocytogenes is significantly more resistant to disinfection or sanitizers than its planktonic counterparts. Many researchers have studied the effects of surface materials on bacterial adhesion and the formation of biofilms. Recent studies have focused on preventing the establishment of L. monocytogenes in niches in the food plant environments.

• 한국임상수의학회지
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• 제34권6호
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• pp.425-428
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• 2017

Silver nanoparticles have marked antimicrobial effects on several pathogens and have been used to control bacterial growth in humans. In the present study, we evaluated the antimicrobial efficacy of silver nanoparticles against the common causative pathogens of canine otitis external through counting of colony forming units. Silver nanoparticles showed significant dose-dependent antimicrobial effects on pathogens. In addition, we conducted antimicrobial susceptibility tests and compared the antimicrobial efficacy of silver nanoparticles. Microorganisms with a high resistance to antibiotics were also resistant silver nanoparticle with low concentration ($5{\mu}g/mL$). However, in high concentration ($15{\mu}g/mL$), almost 100% reduction in the number of CFUs of these pathogens was observed.

• 미생물학회지
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• 제25권2호
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• pp.117-121
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• 1987

오존가스에 감수성이 있는 균주와 저항성을 갖는 여러 종류의 E. coli B를 숙주로 사용하여 T3파아치에 자외선 혹은 오존을 처리하므로서 획득된 재활성 요인에 대하여 실험하였다. 그 결과 오존가스는 소위 SOS기능 단위의 하나인 Weigle효과 (=자 외선 회복)의 유도원우로서 전연 작용하지 못하꺼냐 작용이 미약함을 알 수 있었는데 이 분야의 다륜 보문에서도 일치된 경향을 나타내고 있음을 확인하였다.

• 식물조직배양학회지
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• 제27권5호
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• pp.387-393
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• 2000

The process by which Agrobacterium tumefaciens genetically transforms plants involves a complex series of reactions communicated between the pathogen and the plants. To identify plant factors involved in agrobacterium-mediated plant transformation, a large number of T-DNA inserted Arabidopsis thaliana mutant lines were investigated for susceptibility to Agrobacterium infection by using an in vitro root inoculation assay. Based on the phenotype of tumorigenesis, twelve T-DNA inserted Arabidopsis mutants(rat) that were resistant to Agrobacterium transformation were found. Three mutants, rat1, rat3, and rat4 were characterized in detail. They showed low transient GUS activity and very low stable transformation efficiency compared to the wild-type plant. The resistance phenotype of rat1 and rats resulted from decreased attachment of Agrobacterium tumefaciens to inoculated root explants. They may be deficient in plant actors that are necessary for bacterial attachment to plant cells. The disrupted genes in rat1, rat3, and rat4 mutants were coding a arabinogalactan protein, a likely cell wall protein and a cellulose synthase-like protein, respectively.

• 한국식물병리학회지
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• 제12권2호
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• pp.156-161
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• 1996

세계적으로 구리약제에 대해서 저항성을 나타내는 균주들이 발견되있으며, 이들은 구리약제의 방제효과를 감소시켰다. 국내에서도, 구리 저항성 균주 Xanthomonas campestris. pv. vesicatoria HN94-2, -3, -4, -5, -6 들이 천안지역의 고추재배지에서 처음으로 분리되었으며, 이들 균주들의 nutrient agar에서 황산구리(CuSo\ulcorner)에 대한 최소억제농도(minimum inhibitory concentration, MIC)는 1.4~1.6 mM이었다. 이들은 모두 황산아연(ZnSO\ulcorner)에 대해서는 감수성을 보여, 구리저항성 균주에 대한 방제약제로서 아연 함유 약제를 사용할 수 있을 것이다. 분리된 균주중 HN94-2와 HN94-6을 이용하여 접합(conjugation)을 통해 구리저항성의 전파를 실험한 결과, 이들 두 균주 모두 구리감수성 균주에게 4.3$\times$10\ulcorner에서 1.0$\times$10\ulcorner(transconjugant/donor)의 정도로 구리 저항성이 전이되었다. 이들 HN94-2와 HN94-6 균주의 구리정항성 유전자들은 약 200 kb 정도의 커다란 플라스미드(plasmid)에 존재하며, 이들은 각각 pXVK9402와 pXVK9406이라 명명되었다.

• 미생물학회지
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• 제12권2호
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• pp.69-69
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• 1974

This experiment was carried out to identify and to compare the radiosensitivities of bacteriz isolated from the sources of different radiation exposure histories. Among 10 strains isolated in this investigation, 4 strains of bacteria, Bacillus firmus, Bacillus brevis, Baciilus subtilis and Bacillus sphaericus were isolated from high and low radioactive sites simulaneously. Bacterial strains isolated from radioactive sources such as reactor and isotope production rooms were more resistant to irradiation than the microganisms from medical products and laboratories, however, there was no significance in radiosensitivity in the same species of bacteriz, even if they were isolated from different radiation exposure histories.

• 환경생물
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• 제18권4호
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• pp.441-446
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• 2000

Trichoderma harzianum is an aggressive causal agent of green mold disease on mushroom cultivation. Some bacterial strains isolated, from oyster mushroom compost in Wonju, were found to have in vitro antifungal activity against Trichoderma harzianum ATCC 6385, 6504, and our isolates Trichoderma spp. Y and G. Further in vitro antifungal studies on several strains of phytopathogenic fungi showed that all of 12 phytopathogenic fungal strains were significantly inhibited by the isolated antifungal bacteria in Petri dishes. Of these, KATB 99121 showed the broadest inhibiting effect and displayed as negative coagulase, negative sulfide production and rod shape. KATB 99121 was resistant to ampicillin, chlorampenicol, and kanamycin. Identification of isolates was determined by Biolog GN system, and KATB 99121 was identified as Photobacterium logei because of 96 probability, 0.65 similarity, and 4.97 disturbance. With electron microscopy, thin section of KATB 99121 strain revealed typical rod-like shaped cell (0.6-0.8${\mu}{\textrm}{m}$$\times$1.5-2.0${\mu}{\textrm}{m}$) with prokaryotic structure and organization.