Dietary carotenoids protect human cells from damage.
ABSTRACT A physical chemistry technique based on singlet oxygen luminescence at about 1270 nm and a biological cell membrane technique were used to study the quenching of singlet oxygen by four carotenoids bound to the surface of lymphoid cells. All the carotenoids studied showed a beneficial effect in cell protection, but there were subtle differences between them.
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Chapter: Green Cryosestic Algae[Show abstract] [Hide abstract]
ABSTRACT: Cryoseston inhabits one of the most extreme environments in the Earth biosphere. The phototrophic components are composed exclusively from microorganisms, adapted to life conditions of melting snow. All species occurring in cryosestic assemblages evidently colonised the snowfields secondarily, their ancestors originating from other habitats. Cryosestic communities develop in snowfields and on the surface of glaciers, where the temperature surpasses 0ºC periodically (daily, or over variously long time periods), and the snow changes locally from solid to liquid state. It means, that the temperature adaptability of cryosestic species must allow to start the intense metabolic activities immediately after melting their cells accommodated in snow. Such adaptation also occurs in algae from other biotopes (in subaerophytic, endolithic and terrestrial habitats), but it is the conditio sine qua non in typical cryosestic algae. Another precondition is that the cryosestic microflora can develop only in snowfields and glaciers remaining and persisting in air temperatures above 0ºC over some periods, and under convenient irradiance conditions (cf. Hoham and Duval, 2001). This situation occurs mainly in mountains and polar and subpolar regions over the spring and summer periods.12/2006: pages 321-342;
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ABSTRACT: Carotenoid extracts from shrimp processing discards were evaluated for antioxidant activity. Crude extract and fractions rich in astaxanthin showed strong antioxidant activity as indicated by radical scavenging, reducing activity and metal chelating activity, comparable to that of the known antioxidants α-tocopherol and TBHQ. Singlet oxygen quenching activity of crude extract and its fractions was higher than that of α-tocopherol. Nitric oxide scavenging activity was also higher than α-tocopherol. The ability of the astaxanthin-rich fraction to inhibit the thermal oxidation of phospholipid liposomes, with a protection factor of 22.6 ± 1.7 units, was better than that of α-tocopherol (8.5 ± 1.5 units). The higher antioxidant activity of the astaxanthin-rich fraction was also indicated by a higher protection factor (14.1 ± 3.2 units) compared to α-tocopherol (6.2 ± 0.1 units) against singlet oxygen mediated oxidation of liposomes. The results indicate the potential of shrimp carotenoid extract as a natural antioxidant for possible use in food and biomedical applications.Food Chemistry 09/2012; 134(1):308–314. DOI:10.1016/j.foodchem.2012.02.147 · 3.26 Impact Factor
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ABSTRACT: Solar radiation is a physical force, modulating the earth?s ecosystems. The visible range of the solar spectrum most notably comprises beneficial effects, promoting processes such as photosynthesis. The ultraviolet (UV) portion of the solar spectrum, however, induces various detrimental effects in both terrestrial and aquatic organisms on all systemic levels. I studied the effects of UV-exposure on different UV- and oxidative stress parameters and defence systems against direct and indirect UV-damage in shallow water amphipods. The UV-tolerance was compared in species from two different polar regions (Antarctic King George Island and Arctic Spitsbergen), currently undergoing different degrees of ozone depletion, in relation to a reference species from a temperate North Sea coast, which displays higher natural UV-impact, however, lower ozone depletion compared to the polar areas. I distinguished between dose- and wavelength-dependent effects and also considered the possible influence of nutrition on UV-protective capacities by comparing herbivorous and carnivorous/necrophagous amphipods.