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Wyszukujesz frazę "xanthophylls" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Photoprotection by carotenoids of plantago media photosynthetic apparatus in natural conditions
Autorzy:
Golovko, Tamara
Dymova, Olga
Zakhozhiy, Ilya
Dalke, Igor
Tabalenkova, Galina
Powiązania:
https://bibliotekanauki.pl/articles/1039804.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
carotenoids
photoinhibition
photoprotection
Plantago media
xanthophylls cycle
Opis:
The study of daily changes in photosynthetic rate, of energy used in photochemical and non-photochemical processes, and of carotenoid composition aimed at evaluating the role of xanthophyll cycle (XC) in protection of hoary plantain plants (Plantago media) in nature. The leaves of sun plants differed from shade plants in terms of CO2 exchange rate and photosynthetic pigments content. The total pool XC pigments and the conversion state increased from morning to midday in sun plants. An increase in zeaxanthin content occurred concomitantly with the violaxanthin decrease. About 80% violaxanthin was involved in conversion. The maximum of zeaxanthin in XC pigments pool was 60%. The conversion state of XC was twice as lower in shade plants than that in sun plants. The photosynthesis of sun leaves was depressed strongly at midday, but changes of maximum quantum yield of PS2 (Fv/Fm) were not apparent at that time. The coefficient qN (non-photochemical quenching) in the sun leaves changed strongly, from 0.3 to 0.9 as irradiance increased. The direct relation between heat dissipation and the conversion state of XC in plantain leaves was revealed. Thus, plantain leaves were found to be resistant to excess solar radiation due to activation of qN mechanisms associated with the XC de-epoxidation.
Źródło:
Acta Biochimica Polonica; 2012, 59, 1; 145-147
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of astaxanthin and canthaxanthin in food products by HPLC method
Oznaczanie astaksantyny i kantaksantyny w produktach spożywczych metodą HPLC
Autorzy:
Krępska, Małgorzata
Sieczyńska, Katarzyna
Lasoń-Rydel, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/2175902.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Skórzanego
Tematy:
natural dye
carotenoids
xanthophylls
HPLC
barwnik naturalny
karotenoidy
ksantofile
Opis:
Astaxanthin and canthaxanthin are carotenoids produced mainly by algae, fungi and bacteria. These dyes give the characteristic pink-orange color to salmon, shrimp and flamingo feathers. In the case of farm animals, astaxanthin and canthaxanthin are added to the feed, and their amount is strictly established and should not exceed certain limits. The article presents a method of determination of astaxanthin and canthaxanthin by HPLC method. This analysis determines whether these dyes are detected in the product and what their content are. This makes it possible to assess compliance with the limits and often also to determine the origin of the product.
Astaksantyna i kantaksantyna to karotenoidy wytwarzane głównie przez algi, grzyby i bakterie. Barwniki te nadają charakterystyczny różowo-pomarańczowy kolor piórom łososi, krewetek i flamingów. W przypadku zwierząt gospodarskich astaksantyna i kantaksantyna są dodawane do paszy, a ich ilość jest ściśle określona i nie powinna przekraczać określonych limitów. W artykule przedstawiono metodę oznaczania astaksantyny i kantaksantyny metodą HPLC. Ta analiza określa, czy barwniki te są wykrywane w produkcie i jaka jest ich zawartość. Pozwala to ocenić przestrzeganie limitów, a często także określić pochodzenie produktu.
Źródło:
Technologia i Jakość Wyrobów; 2022, 67; 106--116
2299-7989
Pojawia się w:
Technologia i Jakość Wyrobów
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural aspects of the antioxidant activity of lutein in a model of photoreceptor membranes
Autorzy:
Wisniewska-Becker, Anna
Nawrocki, Grzegorz
Duda, Mariusz
Subczynski, Witold
Powiązania:
https://bibliotekanauki.pl/articles/1039793.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
macular xanthophylls
singlet oxygen
lutein
antioxidants
lipid domains
AMD
Opis:
It was shown that in membranes containing raft domains, the macular xanthophylls lutein and zeaxanthin are not distributed uniformly, but are excluded from saturated raft domains and about ten times more concentrated in unsaturated bulk lipids. The selective accumulation of lutein and zeaxanthin in direct proximity to unsaturated lipids, which are especially susceptible to lipid peroxidation, could be very important as far as their antioxidant activity is concerned. Therefore, the protective role of lutein against lipid peroxidation was investigated in membranes made of raft-forming mixtures and in models of photoreceptor outer segment membranes and compared with their antioxidant activity in homogeneous membranes composed of unsaturated lipids. Lipid peroxidation was induced by photosensitized reactions using rose Bengal and monitored by an MDA-TBA test, an iodometric assay, and oxygen consumption (using EPR spectroscopy and the mHCTPO spin label as an oxygen probe). The results show that lutein protects unsaturated lipids more effectively in membranes made of raft-forming mixtures than in homogeneous membranes. This suggests that the selective accumulation of macular xanthophylls in the most vulnerable regions of photoreceptor membranes may play an important role in enhancing their antioxidant properties and ability to prevent age-related macular diseases (such as age-related macular degeneration (AMD)).
Źródło:
Acta Biochimica Polonica; 2012, 59, 1; 119-124
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carotenoid - membrane interactions in liposomes: effect of dipolar, monopolar, and nonpolar carotenoids
Autorzy:
Wisniewska, Anna
Widomska, Justyna
Subczynski, Witold
Powiązania:
https://bibliotekanauki.pl/articles/1041203.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
macular xanthophylls
β-cryptoxanthin
β-carotene
lutein
spin labeling
AMD
EPR
lipid bilayer
Opis:
Electron paramagnetic resonance (EPR) spin-labeling methods were used to study the effects of carotenoids on the physical properties of saturated phosphatidylcholine (PC) membranes to evaluate the contribution of the terminal hydroxyl groups of xanthophyll molecules to the carotenoid-membrane interaction. Effects of the dipolar, terminally dihydroxylated carotenoid lutein on membrane phase transition, fluidity, order, and polarity were compared with those of monopolar (β-cryptoxanthin) and nonpolar (β-carotene) carotenoids. These effects were monitored at the membrane center as a function of the amount of the carotenoid added to the sample and as a function of temperature for fluid-phase membranes. PC membranes with different thickness (from 12 to 22 carbons in alkyl chains) were used. Carotenoids shifted to lower temperatures and broadened the main phase transition of PC membranes. They decreased the membrane fluidity and increased the order of alkyl chains. Carotenoids also increased the hydrophobicity of the membrane interior. These effects were the strongest for lutein, significantly weaker for β-cryptoxanthin, and negligible for β-carotene. They decreased with the increase of the membrane thickness. Presented results suggest that anchoring of carotenoid molecules at the opposite membrane surfaces by polar hydroxyl groups is significant in enhancing their effects on membrane properties. This manuscript also shows the ability of EPR spin-labeling methods to monitor different membrane properties that can be applied in biotechnological studies with the use of liposomes.
Źródło:
Acta Biochimica Polonica; 2006, 53, 3; 475-484
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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