• Title/Summary/Keyword: Thylakoid membrane

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Studies on the Effect of Polyamine on Chlorophyll Contents and Chloroplast Peroxidase Activities in Rice Leaf Segments (벼잎 절편에서 Polyamine이 엽록소 함량 및 Chloroplast Peroxidase활성에 미치는 영향에 관한 연구)

  • 표병식;김영준강영희
    • KSBB Journal
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    • v.8 no.2
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    • pp.115-121
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    • 1993
  • The effect of polyamine on chlorophyll amount, chloroplast peroxidase and chloroplast thylakoid protein in rice leaf segments which were grown for 10 days(16 hrs, light : 8 hrs, dark) in a hormone-free MS medium containing polyamine was studied. Polyamine treatment increased the chlorophyll contents compared with the control in rice leaf segments. Especially spermine was most effective. Also, in rice leaf segments treated with polyamine chloroplast peroxidase activity was higher than in the control. The treatment with lmM of spermidine increased the enzyme activity by 100%. In polyamine treatment and control two major polypeptide bands corresponding to 56 and 25Kd molecular weight were clearly resolved with other minor bands by SDS-PAGE in the insoluble protein fraction. However, in these bands (56, 25Kd), the total area of protein in treating with polyamine were higher than that of the control. These results suggest that polyamine was an important factor in the chloroplast development of rice seedlings.

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Trends of Photosynthetic Bio-solar Energy Conversion Technology (광합성 전자 추출 기반 바이오 태양광 에너지 전환기술 동향)

  • Kim, Yong Jae;Hong, Hyeonaug;Shin, HyeIn;Yun, JaeHyoung;Ryu, WonHyoung
    • Ceramist
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    • v.21 no.3
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    • pp.233-248
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    • 2018
  • Photosynthesis of plant, algae, and certain types of bacteria can convert solar energy to electrons at high efficiency. There have been many research investigations to utilize this mechanism to develop photosynthetic bio-solar energy systems. In this article, the fundamentals of photosynthetic energy conversion mechanism are explained and various approaches are introduced and discussed.

Delayed Luminescence of Biophotons from Plant Leaves

  • Sung, Baeck-Kyoung;Yi, Seung-Ho;Lee, Chang-Hoon;Yang, Joon-Mo;Kim, Jai-Soon;Soh, Kwang-Sup;Yang, Jong-Soo
    • Journal of the Optical Society of Korea
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    • v.8 no.3
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    • pp.132-136
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    • 2004
  • Delayed luminescence of plant leaves was imaged by a 2-D cooled charge-coupled device. We report the delayed luminescence imaging of normal/injured leaves picked ami the leaves intact. The luminescent intensity was lower in leaf veins, scars and edge cut. The intensity of delayed luminescence from intact leaves was higher than that of picked leaves. These results indirectly support the argument that the delayed luminescence of a photosynthetic system is closely related to the electron transfer process of PSII in the thylakoid membrane.

Correlative Changes between Photosynthetic Activities and Chlorophyll Fluorescence in Wheat Chloroplasts Exposed to High Temperature

  • Young-Nam Hong
    • Journal of Plant Biology
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    • v.37 no.1
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    • pp.37-42
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    • 1994
  • Correlative changes between photosynthetic O2 exchange rates and room temperature Chl fluorescence were investigated in wheat (Triticum aestivum L.) chloroplasts treated with high temperature for 5 min. With increasing treatment temperature, photosynthetic O2 evolution rate mediated by PSII was decreased, showing 50% inhibition at 38$^{\circ}C$ (I50). But PSI activity measured by O2 uptake rates was stimulated as a function of increasing temperature. Dark level fluorescence (Fo)-temperature (T) analysis showed that fluorescence rising temperature (Tr), critical temperature (Tc), and peak temperature (Tp) was 38, 43, and 52$^{\circ}C$, respectively. Quenching analysis of Chl fluorescence showed that both the oxidized fraction of plastoquinone (qQ) and degree of thylakoid membrane energization (qNP) increased up to 4$0^{\circ}C$ and then declined dramatically. These results suggest that Tr is correlated with temperature showing a 50% of inhibition of photosynthesis and under mild high temperature stress, qNP is worth regarding as indicator for heat-induced damage of photosynthesis.

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Effects of iso-Butanol on Photosynthetic Electron Transport Activity in Isolated Spinach Chloroplasts (시금치(Spinacia oleracea L.) 엽록체의 광합성 전자전달 활성에 미치는 iso-Butanol의 영향)

  • 박강은
    • Journal of Plant Biology
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    • v.35 no.3
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    • pp.247-252
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    • 1992
  • The effect of iso-butanol on the electron transport rate of PS I and PS II was investigated in isolated spinach chloroplasts. In photosystem I, the rate of electron transport increased in the presence of 1 to 4% of isobutanol but decreased in 5 to 9% of iso-butanol. But in photosystem II, the rate of electron transport decreased when treated with 0.2 to 1% of iso-butanol. The inhibitory effect of isomers of butanol on PS II electron transport rate increased in the order of 2-butanol, tert-butanol, iso-butanol and I-butanol. This means that PS II activity was affected according to the arrangement of carbon atoms in butanol. The inhibitory effect of iso-butanol reduced when DPC was added in the solution. This means that iso-butanol affects PS II reduction side of thylakoid membrane primarily. The inhibitory effect of iso-butanol was reduced when $Mn^{2+},\;C^{2+}$ or BSA were added in the solution. PS II activity was restored when 1% iso-butanol treated chloroplast solution was diluted to twentyfold or when $Mn^{2+},\;C^{2+}$ or BSA was added to the diluted solution. However, the SDS-PAGE banding pattern of thylakoid membrane proteins was similar even in 2% iso-butanol treated chloroplasts and the control ones. Only in 5% iso-butanol treated chloroplasts these bands were very weak. These observations suggest that low concentrations of iso-butanol releases manganese and calcium ions from chloroplasts and inhibits the electron transport system. This inhibitory effect can be reversible in low concenterations but in high concentrations the inhibitory effect of iso-butanol become irreversible.rsible.

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The first insight into the structure of the Photosystem II reaction centre complex at $6{\AA}$ resolution determined by electron crystallography

  • Rhee, Kyong-Hi
    • Proceedings of the Botanical Society of Korea Conference
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    • 1999.08a
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    • pp.83-90
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    • 1999
  • Electron crystallography of two-dimensional crystalsand electron cryo-microscopy is becoming an established method for determining the structure and function of a variety of membrane proteins that are providing difficult to crystallize in three dimension. In this study this technique has been used to investigate the structure of a ~160 kDa reaction centre sub-core complex of photosystem II. Photosystem II is a photosynthetic membrane protein consisting of more than 25 subunits. It uses solar energy to split water releasing molecular oxygen into the atmosphere and creates electrochemical potential across the thylakoid membrane, which is eventually utilized to generate ATP and NADPH. Images were taken using Philips CM200 field emission gun electron microscope with an acceleration voltage of 200kW at liquid nitrogen temperature. In total, 79 images recorded dat tilt angles ranging from 0 to 67 degree yielded amplitudes and phases for a three-dimensional map with an in-plant resolution of 6$\AA$ and 11.4$\AA$ in the third dimension shows at least 23 transmembrane helices resolved in a monomeric complex, of which 18 were able to be assigned to the D1, D2, CP47 , and cytochrome b559 alfa beta-subunits with their associated pigments that ae active in electron transport (Rhee, 1998, Ph.D.thesis). The D1/D2 heterodimer is located in the central position within the complex and its helical scalffold is remarkably similar to that of the reaction centres not only in purple bacteria but also in plant photosystem I (PSI) , indicating a common evoluationary origin of all types of reaction centre in photosynthetic organism known today 9RHee et al. 1998). The structural homology is now extended to the inner antenna subunit, ascribed to CP47 in our map, where the 6 transmembrane helices show a striking structural similarity to the corresponding helices of the PSI reaction centre proteins. The overall arrangement of the chlorophylls in the D1 /D2 heterodimer, and in particular the distance between the central pair, is ocnsistent with the weak exciton coupling of P680 that distinguishes this reaction centre from bacterial counterpart. The map in most progress towards high resolution structure will be presented and discussed.

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Changes in photosynthesis and carbohydrate synthesis in response to elevated UV-B environment (고 자외선 환경에서 식물의 광합성, 기공조절 및 탄수화물 합성)

  • Yun, Hyejin;Sung, Jwakyung;Lee, Suyeon;Lee, Yejin;Ha, Sangkeun;Sonn, Yeonkyu
    • Korean Journal of Agricultural Science
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    • v.41 no.4
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    • pp.275-281
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    • 2014
  • The ozone depletion has caused plants to be exposed to an increased penetration of solar ultraviolet-B (UV-B) radiation. Enhanced UV-B radiation may have influence on biological functions of plant in many aspects including inhibition of photosynthesis. It is evident that UV-B can potentially impair the performance of all three main component processes of photosynthesis, the photophosphorylation reactions of the thylakoid membrane, the $CO_2$-fixation reactions of the Calvin cycle and stomatal control of $CO_2$ supply. Owing to these depressed reactions, the production and allocation of carbohydrates might be markedly affected, and therefore, the growth and development of plant are distinctly reduced. In this review paper, we provide basic theory and further researches in terms of photosynthesis and carbohydrate synthesis in response to elevated UV-B radiation.

MERCURY-INDUCED ALTERATIONS OF CHLOROPHYLL a FLUORESCENCE KINETICS IN ISOLATED BARLEY (Hordeum vulgare L. cv. ALBORI) CHLOROPLASTS

  • Chun, Hyun-Sik;Lee, Choon-Hwan;Lee, Chin-Bum
    • Journal of Photoscience
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    • v.1 no.1
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    • pp.47-52
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    • 1994
  • Effects of HgCl$_2$-treatment on electron transport, chlorophyll a fluorescence and its quenching were studied using isolated barley (Hordeum vulgare L. cv. Albori) chloroplasts. Depending on the concentration of HgCI$_2$, photosynthetic oxygen-evolving activities of photosystem II (PS II) were greatly inhibited, whereas those of photosystem I (PS I) were slightly decreased. The inhibitory effects of HgCl$_2$ on the oxygen-evolving activity was partially restored by the addition of hydroxyamine, suggesting the primary inhibition site by HgCl$_2$2-treatment is close to the oxidizing site of PS tl associated with water-splitting complex. Addition of 50 $\mu$M HgCI$_2$ decreased both photochemical and nonphotochemical quenching of chlorophyll fluorescence. Especially, energy dependent quenching (qE) was completely disappeared by HgCl$_2$-treatment as observed by NH$_4$CI treatment. In the presence of HgCI$_2$, F'o level during illumination was also increased. These results suggest that pH gradient across thylakoid membrane can not be formed in the presence of 0 $\mu$M HgCl$_2$. In addition, antenna pigment composition might be altered by HgCl$_2$-treatment.

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Regulation of Chlorophyll-Protein Complex Formation and Assembly in Wheat Thylakoid Membrane

  • Guseinova, I.M.;Suleimanov, S.Y.;Aliev, J.A.
    • BMB Reports
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    • v.34 no.6
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    • pp.496-501
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    • 2001
  • Lincomycin, an inhibitor of plastid protein synthesis, was found to block the synthesis of apoprotein P700 with a molecular mass of 72 kDa and the assembly of the Chl a-protein of PS I. Synthesis of the polypeptides of 48, 43.5, and 32 kDa of the PS II complex is also suppressed. This process is accompanied by the disappearance of the PS Two reaction center Chl a at 683 nm, and of the PS One reaction center Chl a at 690, 696, and 705 nm on the fourth derivative of the absorption spectra at 77K. Lincomycin does not affect the synthesis of LHC subunits. It increases the content of the two main Chl forms of LHC at 648 nm (Chl b) and 676 nm (Chl a). The low-temperature fluorescence ratio F736/F685 is also increased. However, the effect of cycloheximide (an inhibitor of cytoplasmic protein synthesis) leads to the reduction of polypeptides of the light-harvesting Chl a/b-protein complex in the range of 29.5-22 kDa. Under these conditions, the relative amount of Chl b and the F736/ F685 fluorescence ratio decrease significantly. This is obviously the result of blocking the LHC I and LHC II synthesis. At the same time rifampicin and actinomycin D (inhibitors which block transcription in chloroplast and nuclear genome, respectively) inessentially affect the characteristics of these complexes.

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High Level Expression of a Protein Precursor for Functional Studies

  • Gathmann, Sven;Rupprecht, Eva;Schneider, Dirk
    • BMB Reports
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    • v.39 no.6
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    • pp.717-721
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    • 2006
  • In vitro analyses of type I signal peptidase activities require protein precursors as substrates. Usually, these pre-proteins are expressed in vitro and cleavage of the signal sequence is followed by SDS polyacrylamide gel electrophoresis coupled with autoradiography. Radioactive amino acids have to be incorporated in the expressed protein, since the amount of the in vitro expressed protein is usually very low and processing of the signal peptide cannot be followed by SDS polyacrylamide gel electrophoresis alone. Here we describe a rapid and simple method to express large amounts of a protein precursor in E. coli. We have analyzed the effect of ionophors as well as of azide on the accumulation of expressed protein precursors. Azide blocks the function of SecA and the ionophors dissipate the electrochemical gradient across the cytoplasmic membrane of E. coli. Addition of azide ions resulted in the formation of inclusion bodies, highly enriched with pre-apo-plastocyanine. Plastocyanine is a soluble copper protein, which can be found in the periplasmic space of cyanobacteria as well as in the thylakoid lumen of cyanobacteria and chloroplasts, and the pre-protein contains a cleavable signal sequence at its N-terminus. After purification of cyanobacterial pre-apo-plastocyanine, its signal sequence can be cleaved off by the E. coli signal peptidase, and protein processing was followed on Coomassie stained SDS polyacrylamide gels. We are optimistic that the presented method can be further developed and applied.