• Title, Summary, Keyword: Thylakoid membrane

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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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Identification and Expression Analysis of Chloroplast p-psbB Gene Differentially Expressed in Wild Ginseng

  • Kim, Doo-Young;Kwon, Ki-Rok;Kang, Won-Mo;Jeon, Eun-Yi;Jang, Jun-Hyeog
    • Journal of Pharmacopuncture
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    • v.15 no.1
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    • pp.18-22
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    • 2012
  • Panax ginseng is a well-known herbal medicine in traditional Asian medicine. Although wild ginseng is widely accepted to be more active than cultivated ginseng in chemoprevention, little has actually been reported on the difference between wild ginseng and cultivated ginseng. Using suppressive subtraction hybridization, we cloned the p-psbB gene as a candidate target gene for a wild ginseng-specific gene. Here, we report that one of the clones isolated in this screen was the chloroplast p-psbB gene, a chlorophyll a-binding inner antenna protein in the photosystem II complex, located in the lipid matrix of the thylakoid membrane. Real-time results showed that the expression of the p-psbB gene was significantly up-regulated in wild ginseng as compared to cultivated ginseng. Thus, the p-psbB gene may be one of the important markers of wild ginseng.

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.

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.

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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    • 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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Photoreactivation of the Oxygen Evolving Center in TIB-treated Chloroplasts of Spinach (TIB로 처리된 시금치의 엽록체에서 산소발생계의 광재활성화)

  • 정화숙
    • Journal of Plant Biology
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    • v.36 no.3
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    • pp.259-266
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    • 1993
  • In Tris-iso-butanol (TIB; Tris buffer pH 8.8 and 1% iso-butanol)-treated chloroplasts, oxygen evolving activity was more inhibited than Tris-treated chloroplasts, but restored highly by 2,6-dichlorophenol-indophenol (DCPIP) and photoreactivation. To understand the mechanism of this results of TIB in photosynthetic electron transport, system, oxygen consumption and evolution of PS I and PS II were measured and protein of the chloroplasts was analysed. In Tris- and TIB-treated chloroplasts, oxygen evolving activity was increased according to the light intensity. Under 48 W·m-2 light intensity, the oxygen evolving activity in both chloroplasts were similar but as the light intensity was increased, TIB-treated chloroplasts showed higher activity. Under 240 W·m-2 light intensity, TIB-treated chloroplasts showed about 25% higher oxygen evolving activity than Tris-treated chloroplasts. Oxygen evolving activity was increased after photoreactivation in both Tris-treated and TIB-treated chloroplasts. Addition of NH4Cl increased the activity in both chloroplasts but in TIB-treated chloroplasts the increase was 30% higher than that in Tris-treated chloroplasts. In PS I, oxygen evolving activity was not inhibited by both treatments whereas in PS II, significant difference was observed between two treatments. Addition of Mn2+ and Ca2+ enhanced oxygen evolution in both Tris- and TIB-treated chloroplasts. Though enhancement was higher in TIB-treated chloroplasts. No difference was observed n protein analysis of the two thylakoid membrane.

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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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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.

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.