뇌 아밀로이드 혈관병과 고혈압성 뇌출혈의 감별에 있어서 Apolipoprotein Eε4와 점상 출혈 분포의 유용성

김용범,이광호,이수주,나덕렬,조수진,정진상,이원용 대한신경과학회 1999 대한신경과학회지 Vol.17 No.1

Stabilization by Glycinebetaine of Photosynthetic Oxygen Evolution by Thylakoid Membranes from Synechococcus PCC7002

Lee, Chin Bum,Hayashi, Hidenori,Moon, Byoung Yong 동의대학교 기초과학연구소 1998 基礎科學硏究論文集 Vol.8 No.1

Active thylakoid membranes were prepared from Synechococcus PCC7002 in a medium that contained glycinebetaine. The oxygen-evolving activity of photosystem Ⅱ of these thylakoid membranes was enhanced and stabilized by the presence of glycinebetaine. The heat stability of the oxygen-evolving activity of the thylakoid membranes was also enhanced by glycinebetaine.

Purification and characterization of ornithine carbamoyltransferase from the chloroplasts of Canavalia lineata leaves

Lee, Chin Bum,Kwon, Young Myung,Kim, Sang-Gu,Lee, Yi 동의대학교 기초과학연구소 1998 基礎科學硏究論文集 Vol.8 No.1

Ornithine carbamoyltransferase (OCT) was characterized from the chloroplasts of Canavalia lineata leaves. The OCT was purified 419-fold with a yield of 7.9% by streptomycin sulfate precipitation, ammonium sulfate fractionation, Sephacryl S-300 gel filtration, hydroxylapatite, and reactive red dye chromatographies. The approximate molecular weight of OCT was 107 kD by measurement from Sephacryl S-300 gel filtration. The subunit molecular weight of the enzyme was 38 kD based on SDS-PAGE. These results suggest that the native enzyme is a trimer. The OCT of C. lineata used not only ornithine but also canaline as a substrate. As for the ornithine-dependent activity, the enzyme had a pH optimum at 8.5 and Michaelis constants of 2.4 mM for L-ornithine and 0.21 mM for carbamoyl phosphate (CP). As for the canaline-dependent activity, Michaelis constants for L-canaline and CP were 11 and 0.13 mM, respectively, at pH 8.0 (optimum pH of canaline-dependent activity). S-carbamoyl-L-cysteine and L-cysteine were very strong inhibitors for the enzyme activity. Inhibition by L-cysteine was shown to be competitive with respect to ornithine, but that was shown to be noncompetitive with respect to canaline. The ornithine-dependent activity was inhibited by 90% in the presence of 2mM Cu^2+ and the canaline-dependent activity was inhibited by 91 and 100% with 2mM Cd^2+ and 2 mM Hg^2+, respectively.

Stabilization by Glycinebetaine of photosynthetic Oxygen Evolution by Thylakoid Membranes from Synechococcus PCC7002

Lee, Chin Bum,Hayashi, Hidenori,Moon, Byoung Yong Korean Society of Molecular Biology 1997 Molecules and cells Vol.7 No.2

RAPID RECOVERY OF PHOTOSYNTHESIS FROM PHOTOINHIBITION IS RELATED TO FATTY ACID UNSATURATION OF CHLOROPLAST MEMBRANE LIPIDS IN CHILLING-RESISTANT PLANTS

LEE, CHIN BUM,MOON, BYOUNG YONG,KANG, IN-SOON 동의대학교 기초과학연구소 1999 基礎科學硏究論文集 Vol.9 No.1

The susceptibility of chilling-resistant spinach plants, and of chilling-sensitive squash plants to photoinhibition was compared in terms of the activity of photosystem Ⅱ, in relation to the degree of fatty acid unsaturation of chloroplast membrane lipids. From thylakoid membranes of the plants, monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol, and phosphatidylglycerol were seperated as major lipid classes. It was found that the content of cis-unsaturated fatty acids of phosphatidylglycerol was greater by 32% in spinach than that in squash. When leaf disks were exposed to light at 5℃, 15℃ and 25℃, photochemical efficiency of photosystem Ⅱ, measured as the ratio of the variable to the maximum fluorescence of chlorophyll, declined markedly in squash plants, as compared to spinach plants. When leaf disks were exposed to strong light in the presence of lincomycin, an inhibitor of protein synthesis in chloroplasts, photoinhibition was accelerated in the two types of plants. Moreover, lincomycin treatment abolished the differences in the degree of susceptibility to strong light, which had been observed between the two types of plants. When the extent of photoinhibition of photosystem Ⅱ-mediated electron transport was compared in thylakoid membranes isolated from the two type of plants, there were no differences in the degree of inactivation of photosystem Ⅱ activity. However, when intact leaf disks were exposed to strong light either at 10℃ or at 25℃, and then were allowed to recover either at 17℃ or at 25℃ in dim light, chilling-resistant plants such as spinach and pea showed marked recovery from photoinhibition, in contrast to chilling-sensitive plants, such as squash and sweet potato, whose recovery was strongly dependent on the temperature. These findings are discussed in relation to the unsaturation of fatty acids in membrane phosphatidylglycerol. It appears that fatty acid unsaturation of membrane lipids accelerates the recovery of photosystem Ⅱ from photoinhibition, without affecting the photo-induced inactivation process of photosystem Ⅱ associated with photoinhibition.

Activity of Antioxidant Enzymes during Senescence in Rice Seedlings

Lee, Cheol-Ho,Lee, Shin-Woo,Chun, Hyun-Sik,Moon, Byoung-Yong,Lee, Byeong-Seok,Koo, Jeung-Suk,Lee, Chin-Bum The Korean Society of Crop Science 2004 Korean journal of crop science Vol.49 No.1

Activity of senescence-induced antioxidant enzymes in the detached rice seedlings (Oryza sativa L. cv. Dongjin) was examined. The levels of $\textrm{H}_2\textrm{O}_2$ content and peroxidase (POD) activity were gradually increased during leaf senescence, whereas catalase activity was decreased. The activity of superoxide dismutase (SOD) was increased, and ascorbate peroxidase (APX) and glutathione reductase (GR) were slightly increased until 3d and 4d of dark induced-senescence, and thereafter were decreased. The activation of all SOD isoforms showed a significant decrease after 6d and 7d. After 4d to 7d of dark senescence, there was a significant effect in enhancing the activity of APX-12 and -13 isoforms as compared with light, despite similar levels in total APX activity. GR-8 and -10 isoforms were more effective in leaf senescence at 4d to 7d, particularly with respect to dark-induced senescence. These results suggest that the metabolism of active oxygen species such as $\textrm{H}_2\textrm{O}_2$ is dependent on various functionally interrelated antioxidant enzymes such as catalase, peroxidase, SOD, APX and GR.

Tire 및 Tube 의 품질 보강에 관한 연구(제2보)

이명환,박창호,이진범,이준수,염홍찬,홍종명,임동호,이종근 한국고무학회 1968 엘라스토머 및 콤포지트 Vol.3 No.1

The physical properties of NR-SBR and NR-BR blends were studied. 1. In blending, tensile strength decreased with increase in synthetic rubber contents. It was most effective when the ratio of NR/Syn. R is 75/25. 2. Tensile strength decreased with order of NR, SBR and BR and modulus after aging is proportional of synthetic rubber contents. 3. Elongation is less influenced by synthetic rubber ratio that on the other hand, the decrease of elongation is proportional to synthetic rubber contents after aging. 4. Hardness decreased with increase in the synthetic rubber contents and on the other hand, the hardness increased after aging.

LOW DISSIPATION OF EXCITATION ENERGY IN THE PHOTOSYNTHETIC MACHINERY OF CHILLING-SENSITIVE PLANTS DURING LOW-TEMPERATURE PHOTOINHIBITION

LEE, CHIN BUM,MOON, BYOUNG YONG,GONG, YONG-GUN,KANG, IN-SOON 동의대학교 기초과학연구소 1999 基礎科學硏究論文集 Vol.9 No.1

Using a squash plant, a chilling-sensitive species, and a spinach plant, a chilling-resistant one, effects of chilling temperature on the photosynthetic machinery were studied in terms of chlorophyll fluorescence. When thylakoid membranes were isolated and subjected to incubation at different temperatures, spinach showed stable photosystem Ⅱ activity at the low temperature side, in contrast to squash which showed quite severe inactivation at low temperature. When parameters of chlorophyll fluorescence were examined, chilling in darkness did not affect either Fv/Fm or photochemical and non-photochemical quenching, in both types of plants. However, chilling of squash plants under irradiance of medium intensity caused a specific decrease in Fv/Fm accompanied by a decline in energy-dependent quenching. Contrastingly, photosystem Ⅱ of spinach plants were not much affected by light-chilling. When the pool size of zeaxanthin was examined after exposure to high light at different temperatures, squash plants was shown to have a much lower content of antheraxanthin + zeaxanthin, as compared to spinach plants, during low-temperature photoinhibition. These results suggest that chilling-sensitive plants have low capacity to dissipate excitation energy nonradiatively, when they are exposed to low-temperature photoinhibition, and, as a consequence, more vulnerable to photoinhibitory damage to the photosynthetic apparatus.

Effect of cupric sulfate on the photosynthetic O₂evolution in chinese cabbage chloroplasts

Lee,Chin-Bum,Park,In-Ho,Young,Il-Wha 東亞大學校附設基礎科學硏究所 1984 基礎科學硏究論文集 Vol.1 No.1

배추(Brassica campestris )잎에서 분리한 엽록체에서 광합성적 산소발생반응에 대한 구리이온의 저해효과를 조사하였다. 분리한 엽록체에 200μM CuSo₄를 처리한 경우 그 활성(H₂O/DCIP)이 완전히 저해되었다. 구리에 의한 저해효과는 구리첨가 후 광하에서 배양하였을 때 시간에 따라 점점 크게 나타났으나, 암처에서 배양하였을 때는 그 저해 정도가 훨씬 미약하였다. 구리이온에 의한 산소발생반응의 저해는 구리이온의 농도뿐 아니라 구리와 엽록소의 비율에 따라 정도가 다르게 나타났다. 구리이온을 처리한 후 일정시간 암처에서 배양한 다음 일정시간 광처리한 경우와 그 반대의 순서로 처리한 경우 저해정도가 큰 차이가 없는 것으로 보아, 광에 의한 저해촉진현상은 그 다음의 암처리에 의해 감소되지 않는 비가역적인 현상으로 사료된다.

CHILLING SENSITIVITY OF CUCUMBER PLANTS MONITORED IN TERMS OF CHLOROPHYLL FLUORESCENCE

LEE, CHIN BUM,KANG, IN-SOON,CHUN, HYUN SIK,SEO, KYE HONG,MOON, BYOUNG YONG 동의대학교 기초과학연구소 1997 基礎科學硏究論文集 Vol.7 No.1

For three cultivars of chilling-sensitive cucumber plants, chilling sensitivity was evaluated in terms of photosynthetic activity using Chl fluorescence techniques. Low-temperature treatment caused a decrease in photosynthetic activities of cucumber leaves, measured as CO₂exchange, as well as the decrease in the stomatal conductance. F_R of the three cultivars decreased after chilling for 24 h in light and the extent of decline of F_R of was the greatest in 'Chosaeng' cultivar. When these plants were recovered from light-chilling, 'Chosaeng' and 'Samchuk' cultivars did not fully restore the original value of F_R after 24 h of recovery, in contrast to 'Ilmi' cultivar which showed a rather efficient recovery. The results of F_R study showed that 'Chosaeng' was most susceptible, whereas Ilmi was most resistant, to chilling among the three cultivars of cucumber plants. When quenching coefficients for chlorophyll fluorescence was analyzed after chilling the cucumber plants for 24 h in light, 'Chosaeng' elicited more rapid declines in the coefficient for photochemical quenching (qQ), non-photochemical quenching (qNP) and energy-dependent quenching (qE) than 'Ilmi'and 'Samchuk' . The implications of these observations are discussed in relation to the growth habits of the respective cultivars in the field. The results showed that measurement of chlorophyll fluorescence was an effective means of screening chilling tolerance of cucumber plants. Furthermore, the study on the chlorophyll fluorescence induction and fluorescence quenching charactersitics showed that low temperature could accelerate inhibition of photosynthesis in chilling-sensitive plants, by limiting Calvin cycle activity and disrupting, in part, the energy dissipation mechanisms of the photosystem Ⅱ.