It is astaxanthin. It is also present in paraflagellar body attached to the base of flagella. Both these structures act as photosensitive organs and direct the euglena towards light.
Astaxanthin (pronounced as-tuh-zan'-thin) is a carotenoid. It belongs to a larger class of phytochemicals known as terpenes. It is classified as a xanthophyll, which means 'yellow leaves'. Like many carotenoids, it is a colorful, fat/oil-soluble pigment. Astaxanthin can be found in microalgae, yeast, salmon, trout, krill, shrimp, crayfish, crustaceans and the feathers of some birds. Professor Basil Weedon was the first to map the structures of astaxanthin.
Astaxanthin, unlike some carotenoids, does not convert to Vitamin A (Retinol) in the human body. Too much Vitamin A is toxic for a human, but astaxanthin is not. However, it is a powerful antioxidant. It is 10 time more capable than other carotenoids.
While astaxanthin is a natural nutritional component, it can be found as a food supplement. The supplement is intended for human, animal and aquaculture consumption. The commercial production of astaxanthin comes from both natural and synthetic sources.
The FDA approved astaxanthin as a food coloring (or color additive) for specific uses in animal and fish foods[3a]. The European Union (actually European Commission) considers it food dye within the E number system,
2006-07-20 23:17:43
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answer #1
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answered by PrAt 3
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Euglena is a common genus of flagellate protozoa, typical of the euglenids, and commonly found in nutrient-rich freshwater, with a few marine species. The cells vary in length from around 20 to 300 μm, and are typically cylindrical, oval, or spindle-shaped with a single emergent flagellum. There are usually many bright green chloroplasts, although some species are colorless. The name comes from the Greek words eus and glêne, or good eyeball, referring to the light-sensitive eyespot.
Over 100 species of Euglena have been described. Marin et al. (2003) revised the genus so that it forms a monophyletic group, moving several species with rigid pellicles to the genus Lepocinclis and including several species without chloroplasts, formerly classified as Astasia and Khawkinea.
The Euglenids are one example of why the Kingdom Protista (a.k.a. Protoctista) makes so much sense in comparison to the older taxonomy, in which protozoa were grouped with the animals and chloroplast containing algae were considered plants. In this group of single celled organisms, the Eugeloids, which are obviously derived from the same ancestral organism, there are both organisms containing chloroplasts that synthesize their own sugars using sunlight and dissolved carbondioxide, and organisms that do not have the capability to perform photosynthesis and thus must ingest or absorb their food.The complex chloroplasts of Euglena (and those of photosynthetic dinoflagellates) are surrounded by three membranes. This is unlike chloroplasts of higher plants and most green algae, which are surrounded by two membranes. The additional membranes present a barrier to import of chloroplast precursor proteins not present in the simpler double membrane chloroplast envelope. In higher plants and most green algae, chloroplast proteins are synthesized on free polysomes and then posttranslationally imported directly into the chloroplast. Protein import into these complex chloroplasts is fundamentally different and occurs in three distinct steps:
Synthesis on polysomes bound to the rough endoplasmic reticulum (ER) with co-translocation into the ER;
Transport from the ER into the Golgi apparatus; and
Import across the three chloroplast membranes.
This fundamental difference in import mechanism is proposed to reflect the different evolutionary origins of these chloroplast types. The endosymbiotic theory postulates that choroplasts are a vestige of ancient symbiotic relationships between host cells and internalized photosynthetic organisms. Chloroplasts with a two-membrane envelope are thought to have derived from an association between a eukaryotic host and a photosynthetic prokaryote, while the complex chloroplasts of Euglena are believed to have resulted from a secondary endosymbiotic association between a eukaryotic host and a photosynthetic eukaryote.
2006-07-20 22:33:10
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answer #2
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answered by Miss LaStrange 5
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Cure Eye Floaters At Home - http://EyeFloaters.neatprim.com
2016-03-04 18:14:00
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answer #3
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answered by Tari 3
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It is a rhodopsin like pigment
2006-07-20 22:37:38
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answer #4
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answered by blind_chameleon 5
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2014-09-13 14:54:44
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answer #5
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answered by Anonymous
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rhodopsin-like pigment
2006-07-20 22:47:11
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answer #6
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answered by r_v_kale 2
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chloroplast? or leukoplast?
2006-07-20 22:34:53
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answer #7
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answered by Anonymous
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