Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "zeaxanthin" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Synthesis of highly 13C enriched carotenoids: access to carotenoids enriched with 13C at any position and combination of positions
Autorzy:
Lugtenburg, Johan
Dawadi, Prativa
Powiązania:
https://bibliotekanauki.pl/articles/1039761.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
astaxanthin
β-carotene
zeaxanthin
canthaxanthin
spheroidene
Opis:
Carotenoids and their metabolites are essential factors for the maintenance of important life processes such as photosynthesis. Animals cannot synthesize carotenoids de novo, they must obtain them via their food. In order to make intensive animal husbandry possible and maintain human and animal health synthetic nature identical carotenoids are presently commercially available at the multi-tonnes scale per year. Synthetically accessible 13C enriched carotenoids are essential to apply isotope sensitive techniques to obtain information at the atomic level without perturbation about the role of carotenoids in photosynthesis, nutrition, vision, animal development, etc. Simple highly 13C enriched C1, C2 and C3 building blocks are commercially available via 99% 13CO. The synthetic routes for the preparation of the 13C enriched building blocks starting from the commercially available systems are discussed first. Then, how these building blocks are used for the synthesis of the various 13C enriched carotenoids and apocarotenoids are reviewed next. The synthetic Schemes that resulted in 13C enriched β-carotene, spheroidene, β-cryptoxanthin, canthaxanthin, astaxanthin, (3R,3'R)-zeaxanthin and (3R,3'R,6'R)-lutein are described. The Schemes that are reviewed can also be used to synthetically access any carotenoid and apocarotenoid in any 13C isotopically enriched form up to the unitarily enriched form.
Źródło:
Acta Biochimica Polonica; 2012, 59, 1; 11-16
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Overexpression of zeaxanthin epoxidase gene from Medicago sativa enhances the tolerance to low light in transgenic tobacco
Autorzy:
Cao, Yuman
Zhang, Zhiqiang
Zhang, Tong
You, Zhang
Geng, Jincai
Wang, Yafang
Hu, Tianming
Yang, Peizhi
Powiązania:
https://bibliotekanauki.pl/articles/1038375.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Medicago sativa
low-light tolerance
zeaxanthin epoxidase
overexpression
Opis:
Zeaxanthin epoxidase (ZEP) plays an important role in xanthophyll cycle which is a process closely related to photosynthesis. However, an impact of ZEP on low-light stress has not been studied. In this study, the functions of an alfalfa (Medicago sativa) zeaxanthin epoxidase gene, MsZEP, in response to low-light stress were investigated by heterologous expression in tobacco (Nicotiana tabacum). Under normal light conditions, the measured parameters were not significantly different between transgenic and wild-type (WT) plants except for non-photochemical quenching value and chlorophyll a content. However, the differences were detected under low-light stress. We found that MsZEP-overexpression tobacco grew faster than WT (p≤0.05). The leaf fresh weight and leaf area of transgenic plants were significantly higher, and the number of stomata was greater in MsZEP-overexpression tobacco. As for photosynthetic characteristics, quantum yield of PSII (ΦPSII) and maximal photochemical efficiency of PSII (Fv/Fm) were not significantly different, whereas non-photochemical quenching (NPQ), net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of MsZEP-overexpression tobacco were significantly higher than in WT plants. However, no significant difference was detected between the two types of tobacco in chlorophyll and carotenoids content. In conclusion, MsZEP can improve the ability of tobacco to withstand low-light stress, which might be due to its stronger photosynthetic activity and the improvement of stomatal density under low light.
Źródło:
Acta Biochimica Polonica; 2018, 65, 3; 431-435
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Can macular xanthophylls replace cholesterol in formation of the liquid-ordered phase in lipid-bilayer membranes?
Autorzy:
Subczynski, Witold
Wisniewska-Becker, Anna
Widomska, Justyna
Powiązania:
https://bibliotekanauki.pl/articles/1039790.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
lutein
spin-labeling
zeaxanthin
liquid-ordered phase
EPR
Opis:
Lateral organization of membranes made from binary mixtures of dimyristoylphosphatidylcholine (DMPC) or dipalmitoylphosphatidylcholine (DPPC) and macular xanthophylls (lutein or zeaxanthin) was investigated using the saturation-recovery (SR) EPR spin-labeling discrimination by oxygen transport (DOT) method in which the bimolecular collision rate of molecular oxygen with the nitroxide spin label is measured. This work was undertaken to examine whether or not lutein and zeaxanthin, macular xanthophylls that parallel cholesterol in its function as a regulator of both membrane fluidity and hydrophobicity, can parallel other structural functions of cholesterol, including formation of the liquid-ordered phase in membranes. The DOT method permits discrimination of different membrane phases when the collision rates (oxygen transport parameter) differ in these phases. Additionally, membrane phases can be characterized by the oxygen transport parameter in situ without the need for separation, which provides information about the dynamics of each phase. In gel-phase membranes, two coexisting phases were discriminated in the presence of macular xanthophylls - namely, the liquid-ordered-like and solid-ordered-like phases. However, in fluid-phase membranes, xanthophylls only induce the solitary liquid-ordered-like phase, while at similar concentrations, cholesterol induces coexisting liquid-ordered and liquid-disordered phases. No significant differences between the effects of lutein and zeaxanthin were found.
Źródło:
Acta Biochimica Polonica; 2012, 59, 1; 109-114
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
    Wyświetlanie 1-5 z 5

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies