Diatoms fucoxanthin

Diatoms Fucoxanthin containing phytoplankton characterized by the presence of a silica-impregnated cell wall. 

Scheme 4 Structures of apo-fucoxanthinoids isolated from the diatom Phaeodactylum tricornutum. 11 apo-lO -fucoxanthinal, 12 apo-12 -fucoxanthinal, 13 apo-12-fucoxanthinal, 14 apo-13 -fucoxanthinone...

Carotenoids Peridinin Fucoxanthin 19 -butanoyloxyfucoxanthin 19 -hexanoyloxyfucoxanthin Alloxan thin Prasinoxanthin Lutein Zeaxanthin Dinoflagellates Diatoms Pelagophytes Haptophytes Cryptophytes Prasinophytes Chlorophytes Cyanobacteria, chlorophytes... 

Figure 15.11 Regression between fucoxanthin concentrations in annual sediment layers versus average annual measured diatom biomass in Himmerfjarden (Sweden), both averaged over 5 y. (Modified from Bianchi et al., 2002a.)...

Fucoxanthin. Yellowish-brown pigment found in some members of the Chromista, including kelps and diatoms. 

This chapter presents a personal historical perspective of the role of carotenoids in photosynthesis. It leads the reader into the early literature on the carotenoids and photosynthesis that are related to the discoveries on the excitation energy transfer and, to a lesser extent, on photoprotection. Excitation energy transfer from the carotenoid fucoxanthin to chlorophyll (Chi) a was shown first in the diatoms by H. Dutton, W. M. Manning and... 

B. Light-Harvesting Complexes Containing Fucoxanthin (FCPs) of Diatoms, Brown Algae... 

Fawley MW, Morton IS, Steward KD and Mattox KR (1987) Evidence fora common evolutionary origin of hght-harvesting fucoxanthin chlorophyll a/c protein complexes of Pavlova gyrans (Prymnesiophyceae) and Phaeodactylum tricomutum (Bacillariophyceae). J Phycol 23 377-381 Friedman AL and Alberte RS (1984) A diatom light-harvesting pigment protein complex Purification and characterization. Plant Physiol 76 483 89... 

Fucoxanthin (Fig. 22-5) is the characteristic brown pigment of diatoms. One end of the molecule has an epoxide, also formed by the action of O2, while the other end contains an allene structure rare in nature. Even so, fucoxanthin may be the most abundant carotenoid of all. The structure of the allene-containing end of the fucoxanthin molecule (turned over from that shown in Fig. 22-5) is also given in Eq. 

The xanthophylls and carotenes of plants are examined conveniently after removal of the chlorophylls by saponification with alkali. For this saponification, add 10 ml of 30% potassium hydroxide in methanol to the centrifuged acetone or methanol extract in the separatory funnel. After 30 min with occasional swirling, add 40 ml of cold petroleum ether (20-40°C)-diethyl ether (1 1) plus 100 ml of 10% aqueous sodium chloride solution. Wash the resultant upper golden-yellow layer with water and take to dryness as above. Prepare the sample solution by dissolving the residue in 1 ml of petroleum ether (60-110°C)-diethyl ether (1 1). This saponification procedure should not be employed with plant extracts containing xanthophylls that are decomposed by alkalies, as are fucoxanthin from diatoms and brown algae and peridinin from dinoflagellates. 

Like all the photosynthetic organisms of the brown lineage, diatoms contain fucoxanthin and two other specific xanthophylls of the class diatoxanthin and diadinoxanthin (Liaaen-Jensen, 1976, 1978 Matsuno and Hirao, 1989). 

The spectra of bands 3 and 4 are shown in Fig. 1. The antenna pigment fraction (Band 3) was enriched in Chi h and MgDVP, and the PSI fraction (Band 4 was depleted in both. The absorption and fluorescence excitation band near 520 nm observed here is similar to that of fucoxanthin and perldinin seen in diatoms [Mann, Myers 1968] and dinoflageHates [Prezelin, Haxo 1976]. These correlations suggest that mlcroxanthln may be another antenna pigment for photosynthesis. 

Alberte RS,Friedman AL,Gustafson DL,Rudnick MS and Lyman H(1981) Lightharvesting systems of brown algae and diatoms,isolation and characterization of chlorophyll a/c and chlorophyll a/fucoxanthin pigment-protein complexes, Biochim.Biophys.Acta 635,304-316. 

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