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Topic: Xanthophyll

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	Process for the formation, isolation and purification of comestible xanthophyll crystals from plants - Patent 5648564
		Xanthophylls are typically present in plant chromoplasts as long chain fatty esters, typically diesters, of acids such as palmitic and myristic acids.
		According to the present invention, a xanthophyll, preferably lutein, zeaxanthin or capsanthin and capsorubin is formed, isolated and purified from xanthophyll diester-containing plant matter, preferably a plant known to contain high concentrations of the desired xanthophyll diester.
		The xanthophyll esters are extracted from the plant, preferably from the flower, fruit or root, with an appropriate organic solvent or a mixture of solvents that are themselves readily removable from the extract.
	www.freepatentsonline.com /5648564.html (3918 words)

	Xanthophyll Summary
		Xanthophylls are present in two large protein-cofactor complexes, present in photosynthetic membranes of organisms using Photosystem I or Photosystem II.
		Xanthophylls (originally phylloxanthins) are yellow pigments of oxycarotenoid type, from the carotenoid group.
		The group of xanthophylls is composed of lutein, zeaxanthin, and α- and β-cryptoxanthin.
	www.bookrags.com /Xanthophyll (476 words)

	Re: What is the specific function of anthocyanin and xanthophyll in plants?
		Xanthophylls are structural components of the light harvesting antenna in chloroplasts.
		The xanthophyll, zeaxanthin, appears to have a role in sensing blue light which is involved in stomatal opening and in phototropism.
		QuiÒones MA and Zeiger E (1994) A putative role of the xanthophyll, zeaxanthin, in blue light photoreception of corn coleoptiles Science 264: 558-561.
	www.madsci.org /posts/archives/nov2001/1006647185.Bt.r.html (265 words)

	Guideline 37
		The yellow color of the carcass and yolk is a result of xanthophyll and associated carotenoids in the feed being absorbed through the intestine, metabolized, and deposited in the skin and fat of the bird, or in egg yolk.
		The concentration of xanthophyll and associated carotenoids in the complete broiler feed is closely correlated to the intensity of the skin color in broiler chickens.
		It is generally accepted by poultry nutritionists that a concentration of 16 grams of xanthophyll per ton of complete broiler feed is adequate to produce a broiler of medium to light pigmentation.
	www.fda.gov /cvm/Guidance/Guideline37.htm (1346 words)

	Botany online: The Secondary Metabolism of Plants - Isoprenoids - Terpenes
		Many carotenes (and xanthophylls) are cyclic at their termini and loose as a consequence the terminal double bond(s).
		Xanthophylls like the common xanthophyll of green leaves or lutein are derived from carotenes.
		Fucoxanthin, the brownish pigment of brown algae and diatoms, is another xanthophyll.
	www.biologie.uni-hamburg.de /b-online/e20/20b.htm (609 words)

	Xanthophyll (Site not responding. Last check: )
		Xanthophyll (originally phylloxanthin) is the yellow pigment found in the leaves of most plants.
		Xanthophyll is also found in animal s, such as egg yolk s and blood plasma.
		The Perdue brand of chicken meat also advertise s that its chickens are a health y golden yellow color because they eat marigold flower s in their feed.
	www.serebella.com /encyclopedia/article-Xanthophyll.html (144 words)

	Photoprotection of apple fruit by the xanthophyll cycle
		The objective of this project was to determine xanthophyll cycle pool size and composition in the peel of apple fruit and its role in protecting fruit from excessive light damage, with the ultimate goal to reduce sunburn occurrence on apple fruit.
		We found that the operation of the xanthophyll cycle in apple peel was affected by canopy-light exposure, developmental stages, nitrogen supply, evaporative cooling, and water stress and that there were differences between cultivars in xanthophyll cycle pool size and lutein content associated with their susceptibility to sunburn.
		The objective of this project is to determine xanthophyll cycle size and the composition of apple peel in relation to photoprotection.
	research.cals.cornell.edu /entity?home=6&id=20686 (497 words)

	Patent 6,773,708
		The preferred type of xanthophyll is astaxanthin, particularly in a form esterified with fatty acids, obtainable by for example culturing the algae Haematococcus sp.
		One aspect of the invention is directed to the use of at least one type of xanthophylls for the production of a medicament for suppression of excessive Th1 cell mediated immune responses and stimulation of Th2 cell mediated immune responses in a patient during ongoing infection and/or inflammation in said patient.
		In a preferred embodiment of the invention, the type of xanthophyll is astaxanthin, preferably in a form esterified with fatty acids.
	www.pharmcast.com /Patents100/Yr2004/Aug2004/081004/6773708_Xanthophylls081004.htm (1475 words)

	Spartanburg SC \| GoUpstate.com \| Spartanburg Herald-Journal (Site not responding. Last check: )
		In plants, xanthophylls are considered accessory pigments, along with anthocyanins, carotenes, and sometimes phycobiliproteins.
		Xanthophylls, along with carotenic pigments are seen when leaves turn orange in the autumn season.
		In diatoms and dinoflagellates the xanthophyll cycle consists of the pigment diadinoxanthin, which is transformed into diatoxanthin (diatoms) or dinoxanthin (dinoflagellates), at high light
	www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=xanthophyll (335 words)

	BioMed Central \| Full text \| Lutein is needed for efficient chlorophyll triplet quenching in the major LHCII antenna ...
		In fact, all of the above-mentioned xanthophylls possess similar absorption characteristics in the visible region of the spectrum and are capable of quenching harmful chlorophyll triplets and reactive oxygen species produced during oxygenic photosynthesis [3].
		Although a small fraction of xanthophylls is likely to be free into the thylakoid lipids, where they catalyze ROS scavenging and reduce lipid peroxidation [6,7], xanthophylls are mainly bound to the Lhc proteins of both PSI and PSII [8].
		Xanthophyll spectral forms and efficiency of energy transfer to Chl a in LHCII monomeric preparations purified by non-denaturing IEF from WT and lut2.1 thylakoids.
	www.biomedcentral.com /1471-2229/6/32 (9614 words)

	In vivo manipulation of the xanthophyll cycle and the role of zeaxanthin in the protection against photodamage in the ...
		In vivo manipulation of the xanthophyll cycle and the role of zeaxanthin in the protection against photodamage in the green alga Chlorella pyrenoidosa -- Schubert et al.
		In vivo manipulation of the xanthophyll cycle and the role of zeaxanthin in the protection against photodamage in the green alga Chlorella pyrenoidosa
		Changes in the Xanthophyll Cycle and Fluorescence Quenching Indicate Light-Dependent Early Events in the Action of Paraquat and the Mechanism of Resistance to Paraquat in Erigeron canadensis (L.) Cronq
	www.jbc.org /cgi/content/abstract/269/10/7267 (310 words)

	Plant Cell (Site not responding. Last check: )
		xanthophyll cycle in the regulation of photosynthetic energy conversion.
		To dissect the role of xanthophylls in photoprotective energy dissipation in vivo, we isolated Arabidopsis xanthophyll cycle mutants by screening for altered nonphotochemical quenching of chlorophyll fluorescence.
		These results, in conjunction with the analysis of npq mutants of Chlamydomonas, suggest that the role of the xanthophyll cycle in nonphotochemical quenching has been conserved, although different photosynthetic eukaryotes rely on the xanthophyll cycle to different extents for the dissipation of excess absorbed light energy.
	plantbio.berkeley.edu:16080 /~niyogi/abstracts/1998a.html (242 words)

	Altered xanthophyll compositions adversely affect chlorophyll accumulation and nonphotochemical quenching in ...
		Altered xanthophyll compositions adversely affect chlorophyll accumulation and nonphotochemical quenching in Arabidopsis mutants -- Pogson et al.
		The xanthophylls, lutein, violaxanthin, and neoxanthin, are enriched
		by the presence of all wild-type xanthophylls because of the distinct
	www.pnas.org /cgi/content/full/95/22/13324 (5070 words)

	Changes in the Xanthophyll Cycle and Fluorescence Quenching Indicate Light-Dependent Early Events in the Action of ...
		Bilger W, Björkman O (1990) Role of the xanthophyll cycle in photoprotection elucidated by measurements of light-induced absorbance changes, fluorescence and photosynthesis in leaves of Hedera canariensis.
		Schubert H, Kroon BMA, Matthijs HCP (1994) In vivo manipulation of the xanthophyll cycle and the role of zeaxanthin in the protection against photodamage in the green alga Chlorella pyrenoidosa.
		Váradi G, Darkó É, Lehoczki E (1998) Altered light response of xanthophyll cycle in herbicide-resistant Erigeron canadensis biotypes in the presence of paraquat.
	www.plantphysiol.org /cgi/content/full/123/4/1459 (5835 words)

	Effects of b-carotene feeding on chlorophyll fluorescence, zeaxanthin content, and D1 protein turnover in rice (Oryza ...
		In addition, the content of zeaxanthin and the xanthophyll cycle pigments pool size (V+A+Z) were increased in comparison with control leaves when the leaves were exposed to high light for 3 h.
		The content of b-Car decreased, while the relative content of pigments of the xanthophyll cycle was almost stable and the extent of photoinhibition increased during the senescence of rice leaves (Yang et al., 2001).
		As time of exposure was prolonged to 180 min, however, the xanthophyll pool size increased by 9 mmol/mol chl(a+b) and 16 mmol/mol chl(a+b) in control and b-Car-treated leaves, respectively, whereas the content of b-Car decreased by 12 mmol/ mol chl(a+b) and 19 mmol/mol chl(a+b), respectively.
	ejournal.sinica.edu.tw /bbas/content/2002/3/bot433-02.html (2454 words)

	xanthophyll
		xanthophyll A yellow oxygen-containing carotenoid, present in chloroplasts.(From Glossary of Biotechnology for Food and Agriculture)
		The yellow xanthophyll and orange carotene colors are always present in the leaves, but when the leaf is busy turning water and carbon dioxide into the sugars...
		The time profiles of plasma xanthophyll concentrations were monitored over the dosing phase, and samples were collected frequently on day 42 and for 24 d after...
	www.mongabay.com /igapo/biotech/xanthophyll.html (84 words)

	Curriculum vitae
		The primary focus of my research is to study the in vivo function of the oxygenated carotenoids, xanthophylls and to clone and characterize the enzymes involved in xanthophyll biosynthesis, specifically the beta and epsilon hydroxylases.
		Xanthophylls (typically lutein, violaxanthin and neoxanthin) are the major pigments in the light harvesting complexes after chlorophyll a and b.
		I have measured the kinetics of the xanthophyll cycle in lut1, as well as the fluorescence parameters (indicative of the state of the photosynthetic apparatus) under varying light conditions.
	www.unr.edu /homepage/ltian/aboutme.html (555 words)

	Intermediates of the xanthophyll cycle (Site not responding. Last check: )
		There are several methods of excess excitation energy dissipation under light stress, the xanthophyll cycle being the one that has the closest links to non-photochemical quenching (NPQ) (Demmig-Adams & Adams, 1996), indicating that it is probably the major dissipater of excess energy under field conditions, although this lacks definite proof.
		However, the stoichiometric role of antheroxanthin (with only one de-epoxidized endgroup) and even zeaxanthin in the NPQ mechanism is a complex function of several factors, including rate of de-epoxidation and epoxidation and the lumen proton concentration (Gilmore, 1997).
		Violaxanthin de-epoxidase, the enzyme responsible for the conversion of violaxanthin to zeaxanthin, has been associated with an extrinsic lumen protein and is activated by lumen pH, which induces binding of the enzyme to the membrane surface.
	rucus.ru.ac.za /~wolfman/Essays/Xanth.html (1730 words)

	Greening under High Light or Cold Temperature Affects the Level of Xanthophyll-Cycle Pigments, Early Light-Inducible ...
		All data are expressed as a percentages of the total xanthophyll pool (V+A+Z) and are the averages of three to five replicate plants.
		Farber A, Jahns P (1998) The xanthophyll cycle of higher plants: influence of antenna size and membrane organization.
		Koroleva OY, Thiele A, Krause GH (1995) Increased xanthophyll cycle activity as an important factor in acclimation of the photosynthetic apparatus to high-light stress at low temperature.
	www.plantphysiol.org /cgi/content/full/120/1/193 (6244 words)

	References - xanthophyll - HORT640 - Metabolic Plant Physiology - Department of Horticulture and Landscape Architecture ...
		The xanthophyll cycle intermediates occur mainly in the light-harvesting complexes of photosystem I and photosystem II.
		Ruban AV, Horton P 1999 The xanthophyll cycle modulates the kinetics of nonphotochemical energy dissipation in isolated light-harvesting complexes, intact chloroplasts, and leaves of spinach.
		Varadi G, Darko E, Lehoczki E 2000 Changes in the xanthophyll cycle and fluorescence quenching indicate light-dependent early events in the action of paraquat and the mechanism of resistance to paraquat in Erigeron canadensis (L.) Cronq.
	www.hort.purdue.edu /rhodcv/hort640c/referen/xanth.htm (3398 words)

	Both xanthophyll cycle-dependent thermal dissipation and the antioxidant system are up-regulated in grape (Vitis ...
		Xanthophyll cycle pool size (A, E), lutein (B, F), ß-carotene (C, G) and neoxanthin (D, H) expressed on the basis of leaf area or Chl at predawn and midday in relation to N content of grape leaves.
		Xanthophyll cycle pool size and composition in relation to the nitrogen content of apple leaves.
		Enhanced employment of the xanthophyll cycle and the thermal energy dissipation in spinach exposed to high light and N stress.
	jxb.oxfordjournals.org /cgi/content/full/54/390/2165 (4708 words)

	DIALOG Dissertation Abstracts (Site not responding. Last check: )
		The contribution of xanthophyll pigment, DD plus DT, absorption to total in vivo pigment absorption was examined in three marine diatoms grown at 6 irradiances between 90 and 750 micro-mol m^-2 s^-1.
		For the purpose of evaluating the photoprotective function of xanthophyll pigments in the natural environment, the relationship between xanthophyll pigments and irradiance was examined during the phytoplankton blooms dominated by diatoms and dinoflagellates in Sagami Bay from the end of April to July 2000.
		This result may indicate that the xanthophyll pigments acted as a photoprotection against excess light energy in natural phytoplankton community.
	aslo.org /phd/dialog/200203-10.html (433 words)

	CNR-->Istituto IBF --> Articoli JCR (Site not responding. Last check: )
		For each site the selectivity for individual xanthophyll species was studied as well as its role in protein stabilization, energy transfer, and photoprotection.
		Putative xanthophyll binding sequences, identified by primary structure analysis as a stretch of hydrophobic residues including an acidic term, were analyzed by site-directed mutagenesis or, in one case, by deleting the entire sequence.
		The mutant proteins were unaffected in their xanthophyll composition, thus suggesting that the target motifs had little influence in determining xanthophyll binding, whereas hydrophobic sequences in the membrane-spanning helices are important.
	www.cnr.it /istituti/ArticoliJCR.html?cds=008&id=31649 (228 words)

	[No title]
		We wished to elucidate whether the xanthophyll cycle plays a key role in dissipating the excesses of absorbed light, as in higher plants, and to characterise the relationship between chlorophyll fluorescence parameters and the content of xanthophyll-cycle pigments.
		The xanthophyll cycle was found to be operative in both species; however, its contribution to overall non-photochemical quenching (NPQ) could only be distinguished in Scenedesmus (15-20% of total NPQ).
		Non-photochemical quenching (NPQ) induced through the xanthophyll cycle can, to a limited extent, represent a regulatory factor in diluted algal cultures grown in outdoor solar photobioreactors, as well as in natural algal phytoplankton populations exposed transiently to high irradiance.
	www-u.life.uiuc.edu /labs/crofts/arc-lit/199909/03091912 (7071 words)

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