• 한국물환경학회지
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• 제28권1호
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• pp.57-62
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• 2012

In this study, the inactivation efficiency of Mycobacterium marinum was evaluated in buffered water (pH 7) using a low pressure ultraviolet (LP-UV) lamp, ultrasonic (US), and UV/US sequential processes. In the UV alone process, 3 log inactivation of the M. marinum was achieved with a UV dose of $120mJ/cm^2$. However, a tailing phase was later observed because M. marinum has a high tendency for cell aggregation. Even though the M. marinum was not inactivated in the US alone process, the hydrophobicity decreased and turbidity increased due to the crumbling of the cell aggregation. Among the candidate processes which were UV alone, US-UV sequential process and UV-US-UV sequential process, the US-UV sequential process showed the highest synergistic effects for M. marinum inactivation. Consequently, US is a very useful process as a UV irradiation pre-treatment to inactivate M. marinum in water.

• Journal of Photoscience
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• 제8권1호
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• pp.13-17
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• 2001

Cucumber leaves subjected to light chilling stress exhibit a preferential inactivation of photosystem(PS) I relative to PSII, resulting in the photoinhibition of photosynthesis. In light chilled cucumber leaves, Cu/Zn-Superoxide dismutase(SOD) is regarded as a primary target of the light chilling stress and its inactivation is closely related to the increased production of reactive oxygen species. In the present study, we further explored that inactivation of PSI in cucumber leaves is not a light chilling specific, but general to various oxidative stresses. Oxidative stress in cucumber leaves was induced by treatment of methylviologen(MV), a producer of reactive oxygen species in chloroplasts. MV treatment decreased the maximal photosynthetic O$_2$ evolution, resulting in the photoinhibition of photosynthesis. The photoinhibition of photosynthesis was attributable to the decline in PSI functionality determined in vivo by monitoring absorption changes around 820 nm. In addition, MV treatment inactivated both antioxidant enzymes Cu-Zn-superoxide dismutase and ascorbate peroxidase known sensitive to reactive oxygen species. From these results, we suggest that chloroplast antioxidant enzymes are the primary targets of photooxidative stress, followed by subsequent inactivation of PSI.

• Journal of Microbiology and Biotechnology
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• 제17권4호
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• pp.616-623
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• 2007

The effects of initial concentration and pulsed pressurization on the inactivation of Clostridium sporogenes spores suspended in deionized water were determined during thermal processing $(TP;\;105^{\circ}C,\;0.1MPa)$ and pressure-assisted thermal processing $(PATP;\;105^{\circ}C\;and\;700MPa)$ treatments for 40 min and 5min holding times, respectively. Different inoculum levels $(10^4,\;10^6\;and\;10^8CFU/ml)$ of C. sporogenes spores suspended in deionized water were treated at $105^{\circ}C$ under 700MPa with single, double, and triple pulses. Thermally treated samples served as control. No statistical significances (p>0.05) were observed among all different inoculum levels during the thermal treatment, whereas the inactivation rates $(k_1\;and\;k_2)$ were decreased with increasing the initial concentrations of C. sporogenes spores during the PATP treatments. Double- and triple-pulsed pressurization reduced more effectively the number of C. sporogenes spores than single-pulse pressurization. The study shows that the spore clumps formed during the PATP may lead to an increase in pressure-thermal resistance, and multiple-pulsed pressurization can be more effective in inactivating bacterial spores. The results provide an interesting insight on the spore inactivation mechanisms with regard to inoculum level and pulsed pressurization.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.75-75
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• 1995

Succinic semialdehyde reductase, one of key enzyme of GABA shunt in CNS, is inactivated by o-phthalaldehyde, The inactivation followed pseudo first-order kinetics, and the second-order rate constant for the inactivation process was 28 M$\^$-1/s$\^$-1/ at pH 7.4 and 25$^{\circ}C$. The absorption spectrum(λ$\_$max/=377nm), fluorescence exitation(λ$\_$max/=340nm) and fluorescence emission spectra (λ$\_$max/=409nm) were consistent with the formation of an isoindole derivative in the catalytic site between a cysteine and a lysine residues about 3${\AA}$ apart. The substrate, succinic semialdehyde, did not protect the enzymatic activity against inactivation, whereas the coenzyme, NADPH, protected against o-phthalaldehyde induced inactivation of the enzyme. About 1 isoindole group per moi of the enzyme was formed following complete loss of the enzymatic activity. These results suggest that the amino acid residues of the enzyme participating in reaction with o-phthalaldehyde more likely residues at or near the coenzyme binding site.

• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1209-1215
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• 2017

Microwave sterilization was performed to inactivate the spores of biofilms of Bacillus cereus involved in foodborne illness. The sterilization conditions, such as the amount of water and the operating temperature and treatment time, were optimized using statistical analysis based on 15 runs of experimental results designed by the Box-Behnken method. Statistical analysis showed that the optimal conditions for the inactivation of B. cereus biofilms were 14 ml of water, $108^{\circ}C$ of temperature, and 15 min of treatment time. Interestingly, response surface plots showed that the amount of water is the most important factor for microwave sterilization under the present conditions. Complete inactivation by microwaves was achieved in 5 min, and the inactivation efficiency by microwave was obviously higher than that by conventional steam autoclave. Finally, confocal laser scanning microscopy images showed that the principal effect of microwave treatment was cell membrane disruption. Thus, this study can contribute to the development of a process to control food-associated pathogens.

• Archives of Pharmacal Research
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• 제21권5호
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• pp.543-548
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• 1998

We examined the immunological properties of the recombinant hepatitis B surface antigen (r-HBsAg) which was expressed in mammalian cell (C127). The cross-immunity of r-HBsAg and plasma-derived hepatitis B surface antigen (p-HBsAg) were tested using Western blotting and ELISA with guinea pig polyclonal antibody and naturally infected human-derived antibody and the both antigens show the same results in their response pattern and intensity, which indicate they have a good cross-immunity. from the measurement of $ED_{50}$ after formalin- or heat-inactivation, both r-HBsAg and p-HBsAg and p-HBsAg showed $ED_{50}$ of 0.2-0.3 in formalin-inactivaton, while r-HBsAg was 0.05-0.09 and p-HBsAg was 0.03-0.07 in heat-inactivation, which means heat-inactivation method is 3-4 times superior in immunogenicity. In the immunopersistency test performed in guinea pig for the period of 3 months with two different adjuvants, antibody titer was 34.2 with muramyl dipeptide adjuvant, which was 1.8 times greater than the antibody titer of 18.9 with $AIPO_{4}$ adjuvant. the mutagenicity of r-HBsAg has the same cross-immunity with p-HBsAg, and heat-inactivation method and muramyl dipeptide adjuvant allow development of r-HBsAg vaccine with excellent immunogenicity.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.838-844
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• 2001

The enzyme Fuc aldolase from Methanococcus jannaschii that catalyzes the aldol condensation of DHAP and L-lactaldehyde to give fuculose-1-phosphate was inactivated by DEP. The inactivation was pseudo first-order in the enzyme and DEP, which was biphasic. A pseudo second-order rate constant of 120$M^{-1}min^{-1}$ was obtained at pH 6.0 and $25{\circ}C$. Quantifying the increase in absorbance at 240nm showed that four histidine residues per subunit were modified during the nearly complete inactivation. The statistical analysis and the time course of the modification suggested that two or three histidine residues were essential for activity. The rate of inactivation was dependent on the pH, and the pH inactivation data implied the involvement of the amino acid residue with a $pK_a$ value of 5.7. Fuc aldolase was protected against DEP inactivation by DHAP, indicating that the histidine residues were located at the active site of Fuc aldolase. DL-Glyceraldehyde, as an alternative substrate to L-lactaldehyde, showed no specific protection for the Fuc aldolase.

• 한국산업보건학회지
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• 제29권3호
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• pp.351-357
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• 2019

Objectives: The objectives of this study were to investigate fungal contamination in a 31-year old university building in Seoul, Korea, and to study the inactivation of fungi using cold atmospheric pressure plasma(CAP). Methods: To investigate the fungal contamination in a university building, air samples were collected from five locations in the building, including two study rooms, a storage room, a laboratory, and a basement. The sampling was performed in a dry season(February to April) and in a wet season(July). To study the inactivation efficacy of fungi by CAP, airborne fungal concentrations were measured before and after the operation of the CAP generator. Results: Humidity was an important factor affecting fungal growth. The airborne fungal concentrations determined in the wet season(July) were significantly higher than those determined in the dry season(February to April). In the basement, the values determined in the dry and wet season were 319 and $3,403CFU/m^3$, respectively. The inactivation efficiency of fungi by CAP was 83-90% over five to nine days of operation. Conclusions: The university building was highly contaminated by airborne fungi, especially in summer. It is concluded that humidity is an important factor affecting fungal growth and CAP is a highly useful technique for inactivation of indoor airborne fungi.

• 한국의학물리학회지:의학물리
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• 제14권1호
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• pp.54-67
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• 2003

N형 칼슘전류의 비활성화 vs 전압곡선은 U형을 보인다 - 즉 칼슘 내향전류의 크기와 비활성화 정도가 어느 정도 일치한다. 이러한 U형 비활성화는 순수한 전압의존성 기전으로 설명되어져 왔으나 칼슘의존성 비활성화 기전 또한 보고되었다. 이 연구에서는 흰쥐 상행 경동맥 결절뉴론을 단일 세포로 얻은 후, whole cell patch clamp technique를 사용하여 N형 칼슘전류를 기록하고, 세포외액의 charge carrier 로서 바륨과 칼슘을 사용하면서, 칼슘이 N형 칼슘통로의 비활성화에 미치는 역할을 알아보았다. charge carrier 로 칼슘을 사용하였을 경우에 바륨을 사용하였을 때에 비하여 비활성화 정도가 증가하였으며 이러한 증가는 세포속 $Ca^{2＋}$ Chelator가 11 mM EGTA 로부터 20 mM BAPTA 로 치환되어도 계속 관찰되었다. 비활성화 vs 전압 곡선은 바륨과 칼슘 모두에서 U형이었다. charge carrier 를 칼슘으로 치환시 추가로 유도되는 비활성화 정도는 바륨사용시의 비활성화 정도와 역비례관계를 보여 두 이온에서 같은 기전으로 비활성화가 일어날 가능성을 시사하였다. 이러한 가능성을 지원해 주는 결과로 5초의 긴 저분극 자극시 바륨과 칼슘을 써서 얻은 전류기록은 2중 지수함수로 잘 그려낼 수 있었고, 그 결과 빠른 성분(시정수: -150 ms) 과 느린 성분(시정수 -2500 ms) 를 얻었다. 칼슘이 각각의 성분에 미치는 효과는 각기 달라서 빠른 성분의 amplitude는 증가하였고 느린 성분의 시정수는 빨라졌다. 칼슘에 의해 빠른 성분의 amplitude는 증가하였으므로 이는 더 많은 채널이 빠른 경로로 비활성화되었음을 시사한다. 빠른 성분의 시정수는 변화하지 않았으므로, 이는 비촬성화의 빠른 경로는 칼슘과 바륨에서 같음을 시사하며 즉 비활성화 기전이 칼슘의존성이 아님을 보여주는 증거이다. 그러나 비활성화의 느린 성분은 칼슘에 의해 그 시정수가 빨라졌으므로 칼슘의존성일 가능성이 있다.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.219.2-220
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• 2003

Effect of lipids on the oxidative inactivation of paraoxonasel (PON1), a HDL -associated antioxidant protein, was investigated, based on the hydrolysis of phenyl acetate. First. various fatty acids were examined for the prevention against the inactivation of PON1 byascorbate/Cu2+ system, which caused a remarkable ($\geq$ 90％) inactivation of PON1, accompanied by a partial loss of histidine residues. (omitted)