• Journal of Plant Biology
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• 제36권3호
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• pp.293-296
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• 1993

Effects of dark treatment and N1-dichlorophenyl-N3-dimethylurea (DCMU) on the desaturation of galactolipids of Dunaliella salina were investigated to see whether light-driven photosynthetic electron transport is involved in in vivo desaturation of galactolipids. The incorporation of radioactive fatty acid precursors ([14C]lauric acid) into galactolipids, mainly composed of prokaryotic molecular species, was most affected among different polar lipid classes by both treatments. The analysis of specific radioactivities of individual galactolipid molecular species revealed that their synthesis was greatly inhibited by the treatments except for eukaryotic molecular species, 18 : 3/ 18 : 3 digalactosyldiacylglycerol, whose desaturation occurs in endoplasmic reticulum.

• Journal of Plant Biology
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• 제31권3호
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• pp.205-215
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• 1988

The effects of simetryne on light induced electron transport and phosphorylation in isolated spinach (Spinacia oleracea L.) chloroplasts were investigated in comparison with sencor and DCMU. Simetryne, like sencor and DCMU, completely, inhibited PSII electron transport and phosphoryltion with 10-6 M treatment but did not inhibit PSI electron transport. Interference with the electron transport pathway was evidenced by the greater sensitivity of oxygen evolution and uptake than phosphorylation. The following order of decreasing inhibitory effectiveness was exihibited; DCMU>simetryne>sencor. The photoacoustic technique was also used to monitor the relative photosynthetic activity in the leaves treated with the herbicides (simetryne, sencor or DCMU) in vivo and in vitro. Photoacoustic measurements on intact leaves provide quantitative information on two related aspects of the photosynthetic process, namely, photochemical energy storage and oxygen evolution. The relative photoacoustic signal of leaves treated with the herbicides showed low level in 21 Hz, but high level in 380 Hz and on isolated chloroplasts (both 21 Hz and 380 Hz) in comparison with that of the untreated leaves. These results suggest that some of photochemical energy is converted into the heat owing to the inhibition of electorn transport pathway by the herbicides.

• Journal of Plant Biotechnology
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• 제4권4호
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• pp.171-178
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• 2002

Chlorophyll (Chl) fluorescence imaging was used to investigate the effectiveness of in vivo incorporation methods for two chemicals, 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU) and methyl viologen (MV) in rice, a monocot, and cucumber, a dicot, leaves. four different methods (vacuum infiltration, floating, transpiration-aided incorporation through petiole and spraying) were compared, and $F_i$ and $F_v$/$F_m$ were chosen for the imaging of the DCMU- and MV-treated leaves, respectively. The effects of the chemicals in plants were generally heterogeneous over the whole leaf area. Moreover, the effectiveness of the treatment of a chemical in plant leaves was dependent on chemical species, plant species, concentration of the chemical, the treatment method, the duration of the treatment, the existence of light and detergent, etc. In conclusion, we suggest that to achieve the proposed effects of chemicals in plants for an actual experiment, these factors must be considered before the chemical treatment, and the best method for the treatment of the chemicals tested was floating and vacuum infiltration in the dicot and the monocot leaves, respectively, as drawn from Chl fluorescence imaging analysis.

• 미생물학회지
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• 제32권1호
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• pp.65-69
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• 1994

Synechococcus sp.의 cyanophage는 early, late viral function 모두 빛을 필요로 하는 것으로 나타났으며 증식 초기 2시간 동안 암처리한 경우 200%의 burst size를 나타내었다. Dark 상태에서의 Synechococcus sp.의 cyanophage증식은 대조군에 비해 11%의 burst size를 나타내었다. 광합성 억제제인 DCMU를 $10^{-6}$M로 처리했을 때 virus yield가 2%로 감소했으며 $10^{-4}$M의 CCCP는 cyanophage의 증식을 거의 중지시켰다. 또한 이러한 숙주세포의 광합성 의존도는 LPP-1, N-1과 AS-1보다는 크나 SM-1보다는 작은 것으로 나타났다.

• BMB Reports
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• 제29권1호
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• pp.58-62
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• 1996

The structural changes in the electron donor side of the PSII reaction center have been monitored since heat treatment ($45^{\circ}C$ for 5 min) of thylakoids is known to decrease the oxygen evolving activity. In heat-treated spinach chloroplast thylakoids, the inhibitory effect of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the electron transport activity of the PSII reaction center from diphenyl carbazide to dichlorophenolindophenol became reduced approximately 3.8 times and [$^{14}C$]-labeled DCMU binding on the D1 polypeptide decreased to 25~30% that of intact thylakoid membranes, implying that the conformational changes of the DCMU binding pocket, residing on the D1 polypeptide, occur by heat treatment. The accessibility of trypsin to the $NH_2$-terminus of the cytochrome b-559 ${\alpha}$-subunit, assayed with Western blot using an antibody generated against the synthetic peptide (Arg-68 to Arg-80) of the COOH-terminal domain, was also increased, indicating that heat-treatment caused changes in the structural environments near the stromal side of the cytochrome b-559 ${\alpha}$-subunit, allowing trypsin more easily to cleave the $NH_2$-terminal domain. Therefore, the structural changes in the electron donor side of the PSII reaction center complexes could be one of the reasons why the oxygen evolving activity of the heat-treated thylakoid membranes decreased.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2008년도 제49회 학술심포지움 및 국제학술대회
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• pp.64.2-64.2
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• 2008

• Journal of Plant Biotechnology
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• 제35권2호
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• pp.141-145
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• 2008

본 연구는 남세균 고유의 프로모터를 포함하는 유전자간 염기서열에 기반하여 환경위해성 검출용 바이오센서를 개발하고자 시도되었다. 포도당 처리에 의해서 유도되는 8종의 유전자 (atpI, ndbA, ctaD1, tkt, pgi, pdh, ppc, 그리고 rydA)의 프로모터 부위를 리포터 유전자의 일종인 발광유전자 (luxAB) 벡터 pILA (Genbank: AJ251840)에 도입시켜 재조합 벡터를 제조한 후 Synechocystis sp. PCC6803을 형질전환시킨 결과, pILA 벡터만을 포함하고 있는 대조구에 비해서 포도당 처리에 의해서 생물발광량이 5-25배 정도 현저히 증가함을 확인하였다. 또한 $Hg^{2+}$, $Cu^{2+}$, $Zn^{2+}$과 같은 중금속, $CN^-$, DCMU, DBMIB와 같은 제초제, 그리고 클로람페니콜이나 리팜피신과 같은 항생제에 의해서 생물발광이 현저히 억제되었다.

• Journal of Ginseng Research
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• 제16권2호
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• pp.124-128
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• 1992

인삼의 엽소현상과 광계 II(photosystem II)의 광수확 엽록소-단백질 복합체(LHCP II)의 광에너지 분배 기작과의 관계를 구명코저 LHCP II의 인산화에 따른 형광 quenching과 광량별 인산화 정도, 그리고 단백질 조성을 조사하였다. 인삼은 DCMU의 존재 하에서 photosystem II의 형광발생량이 양지식물인 콩에 비해 많았으며, 인간화에 따른 형광 quenching율도 현저히 높았다. 또한, 강광(25k1ux 이상)에서 인삼은 인산화에 따른 형광 quenching율이 콩에 비해서 2배정도 높다는 사실을 확인하였다. 엽록소-단백질 복합체(CP-complex)의 조성비율 및 LHCP II를 구성하고 있는 단백질의 앙과 수적인 면에서 비교식물과 큰 차이를 나타내었는데, 24~29kD 범위에서 인삼은 25, 26, 27kD의 major 밴드와 24, 25.3, 28.3kD의 minor밴드로 구성되어 있었으며 광량에 의존적으로 인산화가 증가하는 인삼의 LHCP II 단백질은 24kD 이었다.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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• pp.63-67
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• 1999

We have isolated more than a dozen cDNA clones corresponding to genes that were expressed in Arabidopsis leaves when they were kept in the dark. The nucleotide sequence analysis showed that some of the clones encoded proteins with significant homology to $\beta$-glucosidase (din2), branched-chain $\alpha$-keto acid dehydrogenase subunit E1$\beta$(din3), and another subunit E2 (din4), yeast RAD23 (din5), asparagine synthetase (din6), pre-mRNA splicing factor SRp35 (din7), phosphomannose isomerase (din9), seed imbibition protein (din10), and 2-oxoacid-dependent oxidase (din11). Accumulation of transcripts from din3,4,6 and 10 occurred rapidly after the plants were transferred to darkness. Transcripts from din2,9, and 11 could be detected only after 24 h of dark treatment. Inhibition of photo-synthesis by DCMU strongly induced the accumulation of transcripts from those genes, and application of sucrose to detached leaves suppressed the accumulation both in the dark and by DCMU. These observations indicate that expression of the genes is caused by sugar starvation resulted from the cessation of photosynthesis. We further showed that din2-encoded protein also accumulated in senescing leaves. Given these results, possible roles of din genes in leaves in the dark and senescing leaves are discussed.

• Journal of Photoscience
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• 제9권2호
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• pp.373-375
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• 2002

Lhcb genes encoding light-harvesting chlorophyll-a/b binding (LHC) proteins of photosystem (PS) II were comprehensively characterized using the expressed sequence tag (EST) databases in the green alga, Chlamydomonas reinhardtii. The gene family was composed of eight Lhcb genes including four new genes, which were isolated and sequenced. The effects of light intensity on the levels of mRNAs accumulation of multiple Lhcb genes were studied under various conditions. The results indicate that Lhcb genes are coordinately regulated in response to light conditions, and repressed when the input light energy exceeded the requirement for $CO_2$ assimilation. The effects of high light on the expression of the Lhcb genes observed in the presence of an electron transport inhibitor, DCMU, and in mutants deficient in photosynthetic reaction centers suggest the presence of two alternative mechanisms for regulating the genes expression under high-light conditions.