• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.286-294
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• 1987

This experiment was carried out to investigate the bacteriolytic action of the egg white lysozyme isolated from Korean native Ogol fowl and to obtain the data for utilization of the enzyme as a food preservative. Staphyococcus aureus phage type 29 and Bacillus subtilis ATCC 6633 among the microorganisms tested were lyzed by the treatment with 0.05% lysozyme, but Staphylococcus aureus phage type 57 in addition to E. coli etc. was found to be a lysozyme- insensitive species. The lysis of S. aureus phage type 29 was maximized when incubated in nutrient broth (pH 7.0) at $37^{\circ}C$ for 24 hours and suspended it to absorbance 0.6 at 540nm in 0.05M sodium acetate but fer (pH 4.5) and then treated it with the 0.05% lysozyme for 30 min. at $30^{\circ}C$. It was found that the effect of 0.05% lysozyme in combination with 1% glycine on the growth inhibition of S. aurecus phage type 29 increased more 50% than that in the absence of glycine, but not effect with other any additeves and metal ions tested.

• Journal of the korean veterinary medical association
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• v.25 no.10
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• pp.595-606
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• 1989

항원제시세포(APC)와 보조T세포 간의 협력작용에 의하여 활성화된 작동세포(NK세포, CTL, K세포, 대식세포, 과립구 등)의 종양세포, 이식장기 및 세포내기생세균에 감염된 각종 세포에 대한 세포독성작용은 생체방어를 위한 중요한 세포성면역기전이다. 지난 몇 년간 세포성면역기전에 관한 많은 연구에도 불구하고 T림파구매개성 세포독성작용의 면역생물학적기전은 확실히 밝혀있지 않다. 지금까지 알려진 중요한 연구내용을 요약하면 다음과 같다. 1. 세포독성작용을 나타내는 작동세포로는 NK세포, CTL, K세포, 대식세포/단핵구 및 과립구가 있다. 2. T세포의 세포표면항원분자군(CD)으로는 $CD_{2},\;CD_{3},\;CD_{4}[Ly_{3}T_{4}],\;CD_{5}[=Ly_{1}],\;CD_{7},\;CD_{8}[Ly_{2,3}]$가 있으며 $CD_{4}$는 보조Ttpvhdml 특이마커이고 $CD_{8}$는 세포독성 T세포 및 억압T세포의 특이마커이다. 주요 T세포수용체(TCR)는 $CD_{4}$ 또는 $CD_{8}$ 분자와 가까이 연합된 이향체($TCR-{\alpha}{\beta}/TCR-{\gamma}{\delta}$이며 보조 T세포 $CD_{4}$(마우스 $L_{3}T_{4}$)는 수용체와 연합되어 있는반면 억압 T세포 $CD_{8}(Ly+_{2,3})$는 항원수용체와 연합되어 있다. 3. T세포는 Ti-$CD_{3}$(항원/MHC) 복합체를 통한 '항원가교'에 의한 자극(항원인식)과 $CD_{2}$를 통한 비특이경로에 의하여 활성화(분화증식)된다. 비특이경로를 통한 활성경로에서 T세포($CD_{4}$ 및 $CD_{8}$)가 활성화되기 위하여는 보조T세포가 생산하는 IL-2을 요구하며 IL-2의 자극으로 분화증식된 $CD_{8}$는 세포독성능을 나타내지만 $CD_{4}^{+}$는 여전히 세포독성능을 나타내지 못한다. 4. 보조T세포는 class II MHC분자와 연합된 항원을 식별하는 반면 세포독성T세포는 class I MHC 분자와 연합된 항원을 식별한다. 5. 림파구 매개성 세포독성은 접촉(conjugati-on), 탈분극(depolarization), 용해계획(progra-mming), 용해(lysis) 및 재순환(recycling)의 단계를 거쳐 진행된다. 6. 표적세포살해매체로는 perforin / PFP / cy-tolysin, lymphopores, lymphotoxins, protone, cytolytic enzymes가 알려졌으며 세포독성작용은 이들 이외에도 여러 가지 매체를 통한 복합작용으로 추정된다. 7. CTL 매개성 표적세포의 주요 대사변화는 actomyocin ATPase의 증가, phosphocreatine과 ATPase의 소모, ATP 의존성 $Na^{+}/K^{+}$ 펌프작용의 중지, ATP 의존성 $Ca^{2+}$ 유출감소 및 세포내 축적이 관찰된다. 8. $Ca^{2+}$의 축적으로 세포막 교질 침투손상을 주어 수분의 유입을 증가시킴으로써 수포형성, 핵붕괴, 사립체팽화 및 정상세포 구조상실(Zeiosis)이 있다. 결론적으로 CTL 매개성 세포독성작용은 PFP, LT, TNF, 유사 TNF / LT 및 기타 매체를 통한 복합작용이며 세포살해기전은 지속적 대사소모와 정형적 세포구조(핵 및 세포질)의 파괴에 의한 것이다.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.397-402
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• 1985

The fermentation of various sugars by C. thermosaccharolyticum was examined under pH controlled, anaerobic condition. The kinetic model for Product formation at various sugars was the combination of growth and non-growth associated mode. In the utilization of a single sugar, glucose was the best carbon source for growth. The specific growth rate of glucose, xylose and cellobiose were 0.363 h$^{-1}$, 0.242 h$^{-1}$ and 0.144 h$^{-1}$ respectively. The production of ethanol from glucose showed a negatively growth associated mode, so the higher growth rate decreased the productivity of ethanol. The maximum concentrations of the produced ethanol were 2.42 g/l, 3.76 g/l, and 3.4 g/l on glucose, xylose, and cellobiose. No glucose was detected during cellobiose fermentation. Sequential utilization of sugars was observed in the mixtures of glucose, xylose and cellobiose. It preferred glucose, followed by xylose and then cellobiose. The presence of other sugars had little or no effect on the rate of another sugar utilization. Cell lysis at the end of fermentation occured more slowly in the mixtures of sugars than a single sugar.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.594-598
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• 2002

The changes in DNA damage were investigated during storage after irradiation. Kiwi, orange and pear were irradiated at 0.1, 0.3, 0.5, 0.7 and 1.0 kGy and stored for 3 months at 4$^{\circ}C$. The comet assay was applied to the sample seeds alt the beginning of irradiation and at the end of storage. Seeds were isolated and crushed, and the suspended cells were embedded in an agarose layer. After lysis of the cells, they were electrophoresed for 2 min and then stained. DNA fragmentation in seeds caused by irradiation was quantified as tail length and tail moment (tail length $\times$ % DNA in tail) by comet image analyzing system. Immediately after irradiation, the differences in tail length between unirradiated and irradiated fruit seeds were significant (p<0.05) in kiwi, orange and pear seeds. With in-creasing the irradiation doses, statistically significant longer extension of the DNA from the nucleus toward anode was observed. The results represented as tail moment showed similar tendency to those of tail length, but tile latter parameter was more sensitive than the former. Similarly even 3 months after irradiation, all the irradiated fruit seeds significantly showed longer tail length than the unirradiated controls. These results indicate that the comet assay could be one of the simple methods of detecting irradiated fruit seeds. Moreover, the method could detect DNA damage even after 3 months after irradiation.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.591-599
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• 1996

This study was undertaken to investigate the cytotoxicity of orthodontic wires after doing various treatments to the wires. 018x025 inch Stainless steel(A) and Co-Cr(B) wires were used and each of them were divided into 4 groups. A-1 and B-1 groups were as received state, and A-2 and B-2 groups were heat treated. A-3 and B-3 groups were electropolished after heat treatment, and A-4 and B-4 groups were soldered with Ag-solder. Each group had 3 wires and these were sterilized with Ethylene Oxide gas. We used human gingival fibroblast cell culture and agar overlay technique to investigate the cytotoxicity of each group of wires. The cytotoxicity of wire was assessed using reaction index (zone index/lysis index). The findings of this study were as follows. 1. Both of the stainless steel wire and Co-Cr wire showed no cytotoxicity in as received state. 2. Heat treatment or electropolishing of the wires had no effect on the cytotoxicity of the wires 3. Soldered stainless steel wires showed a little wider zone of discoloration than soldered Co-Cr wires, but the zone index and cytotoxicity(reaction index) was not different. 4. Soldered wires showed moderate cytotoxicity in both of the wires.

• Korean Chemical Engineering Research
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• v.44 no.1
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• pp.40-45
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• 2006

The baculovirus-insect Drosophila melanogaster S2 cell system combines advantages of conventional baculovirus system and non-lytic S2 cell system because baculoviruses can infect non-permissive cells such as mammalian and Drosophila S2 cells but cannot replicate themselves inside the cells. In the present work, we investigated effects of infection conditions on production of green fluorescent protein (GFP) as a target protein using this baculovirus-S2 cell system. Even though higher MOI and longer baculovirus contact time showed better GFP expression yield during the shorter period, overall protein yield could be lower during the longer period due to the relatively higher cell detachment and lysis (lower cell viability). In addition, maintaining high MOI will be not practical for large-scale cell culture. Therefore, instead of maintaining high MOI, we found that high initial cell number and concentrated (10X) baculovirus volume can confer comparable protein expression even under the moderate MOI condition. Also, we found that the post-infection time that is connected to state of cells after infection was an important factor for production yield.

• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.172-178
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• 2010

The bloom of the genus Stephanodiscus was gradually extinguished after 18 April. Counts of bacterial population were increased as the diatom bloom was disappeared. Numbers of the heterotrophic nanoflagellates and ciliates were also increased during the disappearance of the bloom. The densities of the mesozooplankton, the major predator of the diatoms, started to increase in April. However, their growth was suppressed during the bloom period of the diatoms (from January to March). During the bloom period of the diatoms, the monthly average value of the basic productivity amounted up to 11,765.7 mgC $m^{-2}day^{-1}$, which is relatively high value considering the low temperature and light during that period. The growth rate of phytoplankton in March, when the bloom was beginning to be supressed was 0.007. The growth rate of phytoplankton was negative value in April when the decreasing of the algal density was started.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.730-738
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• 1992

Filtration characteristics according to membrane materials were studied In the ultrafiltration of anaerobic digestion broth as a post treatment method. A series of resistances for different membranes were quantitatively assessed on the basis of the resistance-in-series model. Flux behavior observed with the digestion broth was irrelevant to initial water permeabilities of each membrane. The fluoro polymer membrane showed the most significant improvement of flux with increase of cross-flow velocity, which suggests that the cake layer formed on this membrane is more weakly attached to the membrane surface than those on the other membranes. Flux reduction during longtime running was attrib-used to the polarization layer resistance ($R_p$) as well as the fouling layer resistance($R_f$). Continuous increase of $R_p$ may reflect the variation in the characteristics of cake layers, which could result from size, shape, and structure changes due to lysis and growth of biomass. Hydrophilic cellulosic membrane had a much lower fouling tendency than hydrophobic polysulfone membrane. The depressurization method induced a small increase in flux of $5-10L/m^2/h$. During washing and cleaning, filtrability of each membrane was rapidly recovered within 15 minutes until a stationary value was reached.

• The Journal of the Korean Society for Microbiology
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• v.35 no.2
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• pp.97-108
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• 2000

Two-dimensional gel electrophoresis (2-DE) is an essential tool of proteomics to analyse the entire set of proteins of an organism and its variation between organisms. Helicobacter pylori was tried to identify differences between strains. As the first step, whole H. pylori was lysed using high concentration urea contained lysis buffer [9.5 M Urea, 4% CHAPS, 35 mM Tris, 65 mM DTT, 0.01% SDS and 0.5% Ampholite (Bio-Rad, pH 3-10)]. The extract ($10\;{\mu}g$) was rehydrated to commercially available immobilised pH gradient (IPG) strips, then the proteins were separated according to their charges as the first dimensional separation. The IPG strips were placed on Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) to separate according to molecular mass of the proteins as the second dimension. The separated protein spots were visualised by silver staining in order to compare different expression of proteins between strains. Approximately 120 spots were identified in each mini-protein electrophoresised gel, furthermore about 65 to 75 spots were regarded as identical proteins in terms of pI value and molecular weight between strains used. In addition, distinct differences were found between strains, such as 219-1, Y7 and Y14, CH150. Two representative strains were examined using strips which had pH range from 4 to 7. This strips showed a number of isoforms which were considered large spots on pH range 3-10. Furthermore, the rest of spots on pH 4-7 IPG strips appeared very distinctive compared to broad range IPG strips. 2-DE seems to be an excellent tool for analysing and identifying variations between H. pylori strains.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.561-567
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• 1991

This study was designed to investigate the productivity of L-methionine by the method of protoplast fusion between Brevibacterium flavum ATCC 14067 and Corynebacterium glutamicm ATCC 13032, and then L-methionine production was performed to continuous fermentation using the immobilized fusant cells. Mutants B. flavum K 104($thr\;met\;Km^{r}\;Et^{r}\;Sm^{r}\;Tm^{r}\;as\;genetic\;marker$) and C. glutamicum B 70($thr\;Hos\;Km^{r}\;Et^{r}\;Sm^{r}\;Tm^{r}as\;genetic\;marker$) were isolated by MNNG treatment. On the other hand, protoplast of mutants were formed to treat with lysis solution containing $500{\mu}g/ml$ of lysozyme. The ratios of protoplast formation and regeneration were 99% and $64{\sim}66%$ respectively. Fusion frequency between B. flavum K 104 and C. glutamicum B 70 showed the $3.5{\times}10^{5}$ in the 35% polyethylene glycol(PEG6000) containing 3% PVP solution. The productivity of L-methionine by fusant BFCG 37 immobilized with sodium alginate was 0.89 g/l the batch fermentation and was $18.75mg/^{1}hr\;^{1}$ on the continuous fermentation at $30^{\circ}C$ for 72 hr.