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Wyszukujesz frazę "xanthophyll cycle" wg kryterium: Temat

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    Wyświetlanie 1-4 z 4
    Tytuł:
    Seasonal changes of violaxanthin cycle pigment de-epoxidation in wintergreen and evergreen plants
    Autorzy:
    Dymova, Olga
    Golovko, Tamara
    Powiązania:
    https://bibliotekanauki.pl/articles/1039803.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    de-epoxidation state
    carotenoids
    xanthophyll cycle
    Opis:
    We studied carotenoids composition and the activities of the xanthophylls pigments in evergreen conifers (Abies sibirica, Juniperus communis, Picea obovata) and dwarf-shrub (Vaccinium vitis-idaea), and in wintergreen herbaceous plants (Ajuga reptans, Pyrola rotundifolia) growing near Syktyvkar (61°67/ N 50°77/ E). The carotenoid pool consisted mainly of following xanthophylls: lutein (70%), neoxanthin (7-10%) and a xanthophylls cycle component - violaxanthin (3-15%). Zeaxanthin and antheraxanthin were found in conifer samples collected in December-March while in other species - during all year. A direct connection between xanthophyll pigment de-epoxidation level and light energy thermal dissipation was shown only for boreal conifer species. It is proposed that zeaxanthin plays a central role in the dissipation of excess excitation energy (nonphotochemical quenching) in the antenna of photosystem II (PSII). We conclude that the increase in the extent of de-epoxidation is beneficial for the retention of PSII activity for conifers in early spring and for herbs in summer.
    Źródło:
    Acta Biochimica Polonica; 2012, 59, 1; 143-144
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species
    Autorzy:
    Kruk, Jerzy
    Szymańska, Renata
    Powiązania:
    https://bibliotekanauki.pl/articles/1040836.pdf
    Data publikacji:
    2008
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    violaxanthin de-epoxidase
    Cuscuta
    xanthophyll cycle
    zeaxanthin epoxidase
    neoxanthin
    lutein epoxide cycle
    Opis:
    In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.
    Źródło:
    Acta Biochimica Polonica; 2008, 55, 1; 183-190
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zeaxanthin epoxidation - an in vitro approach
    Autorzy:
    Kuczyńska, Paulina
    Latowski, Dariusz
    Niczyporuk, Sylvia
    Olchawa-Pajor, Monika
    Jahns, Peter
    Gruszecki, Wiesław
    Strzałka, Kazimierz
    Powiązania:
    https://bibliotekanauki.pl/articles/1039789.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    Arabidopsis thaliana mutants npq1
    model system
    npq2
    xanthophyll cycle
    zeaxanthin epoxidation
    Opis:
    Zeaxanthin epoxidase (ZE) is an enzyme operating in the violaxanthin cycle, which is involved in photoprotective mechanisms. In this work model systems to study zeaxanthin (Zx) epoxidation were developed. Two assay systems are presented in which epoxidation of Zx was observed. In these assays two mutants of Arabidopsis thaliana which have active only one of the two xanthophyll cycle enzymes were used. The npq1 mutant possesses an active ZE and is thus able to convert Zx to violaxanthin (Vx) but the violaxanthin de-epoxidase (VDE) is inactive, so that Vx cannot be converted to Zx. The other mutant, npq2, possesses an active VDE and can convert exogenous Vx to Zx under strong light conditions but reverse reaction is not possible. The first assay containing thylakoids from npq1 and npq2 mutants of A. thaliana gave positive results and high efficiency of epoxidation reaction was observed. The amount of Zx was reduced by 25%. To optimize high efficiency of epoxidation reaction additional factors facilitating both fusion of the two types of thylakoids and incorporation of Zx to their membranes were also studied. The second kind of assay contained npq1 mutant thylakoids of A. thaliana supplemented with exogenous Zx and monogalactosyldiacylglycerol (MGDG). Experiments with different proportions of Zx and MGDG showed that their optimal ratio is 1:60. In such system, due to epoxidation, the amount of Zx was reduced by 38% of its initial level. The in vitro systems of Zx epoxidation described in this paper enable analysis some properties of the ZE without necessity of its isolation.
    Źródło:
    Acta Biochimica Polonica; 2012, 59, 1; 105-107
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improvement of plant heat tolerance by modification of xanthophyll cycle activity
    Autorzy:
    Trojak, Magdalena
    Skowron, Ernest
    Powiązania:
    https://bibliotekanauki.pl/articles/1178460.pdf
    Data publikacji:
    2017
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    ascorbic acid (AsA);
    calcium ions (Ca2+)
    dithiothreitol (DTT)
    heat stress
    plant protection products (PPPs)
    putrescine (Put)
    xanthophyll cycle
    Opis:
    Plants are sessile organisms hence environmental factors such as excessive light and high air temperature lead to significant reductions of their productivity and quality of gained yield. In fact, scientific and agriculture hubs make lots of efforts to improve crop tolerance to elevated temperature, selecting more tolerant varieties. We analyzed less expensive and highly efficient method to improve resistance of well-known cultivars of crop plant by reversible modification of xanthophyll cycle. It functions as a safety valve to adjust energy transfer and protects fragile structures of photosynthetic machinery from excessive light, especially accompanied by heat or water stress. Efficiency of modified xanthophyll cycle activity was measured after pre-treatment with four, chemically different regulators, with or without light illumination. Analyses were carried out on barley (Hordeum vulgare L.) cv. Zenek treated with ascorbic acid (AsA), dithiothreitol (DTT), putrescine (Put) and calcium ions (Ca2+). To measure the scale of thermal energy dissipation we traced energy transfer absorbed by PSII with PAM chlorophyll fluorescence technique. Results showed clear correlation between AsA (activator of violaxanthin de-epoxidase) treatment and stimulation of the Φ(NPQ) at increased temperature. DTT (inhibitor of violaxanthin de-epoxidase) decreased the cycle activity at 45 °C at the same time increasing its value at 35°C, caused by interaction with other enzymes. Action of Put (hydrogen ions buffer) concerned mainly a non regulated Φ(NO) energy quenching. We noticed that application of Ca(NO3)2 (Ca2+ source for enzyme activity) reduced the Φ(NPQ) at 45 °C and stimulated it at 25 °C. Obtained results confirmed postulated possibility of creating new type of plant protection products (PPPs) able to precisely manage natural mechanisms of heat resistance.
    Źródło:
    World Scientific News; 2017, 70, 2; 51-70
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-4 z 4

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