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Hepatoprotective Marine Phytochemicals
Published in Se-Kwon Kim, Marine Biochemistry, 2023
BR Annapoorna, S Vasudevan, K Sindhu, V Vani, V Nivya, VP Venkateish, P Madan Kumar
Phlorotannins (1,3,5-trihydroxy benzene) are polymers of phloroglucinol exclusively found in brown algae and biosynthesized through the acetate–malonate pathway. Different types of phlorotannins have been identified from different marine species, a few of which include Phlorofucofuroeckol A, dieckol, dioxinodehydroeckol, eckstolonol, triphlorethol-A, fucosterol, phloroglucinol, eckol, phlorofucofuroeckol-A, 2-phloroeckol, 7-phloroeckol (Kim et al. 2009). Among marine brown algae, Ecklonia cava, Ecklonia stolonifera, Ecklonia kurome, Eisenia bicyclis, Ishige okamurae, Sargassum thunbergii, Hizikia fusiformis, Undaria pinnatifida, and Laminaria japonica have been reported for phlorotannins with beneficial health biological activities (Li et al. 2011). A few of the carotenoids isolated from marine sources such as algae, fungi, and bacteria include astaxanthin (Hematococcus pluvialis), fucoxanthin (Sargassum siliquastrum, Hijikia fusiformis, Undaria pinnatifida, Laminaria japonica), tedaniaxanthin, lutein (Dunaliella salina), siphonaxanthin, lycopene (haloarchaea), antheraxanthin, zeaxanthin (Halophila stipulacea), violaxanthin, neoxanthin, peridinin (Heterocapsa triquetra), β-cryptoxanthin β-carotene (Dunaliella salina), ketocarotenoids, canthaxanthin (Thraustochytrium strains ONC-T18 and CHN-1), echinenone, diadinoxanthin, dinoxanthin, and alloxanthin (Galasso et al. 2017).
Fucoxanthin
Published in M. Jerold, V. Sivasubramanian, Biochemical and Environmental Bioprocessing, 2019
Lohr and Wilhelm (1999) found out that violaxanthin as the major precursor for the synthesis of almost all carotenoids. Fucoxanthin in the diatom Phaeodactylum tricornutum was synthesized from violaxanthin through diadinoxanthin. Lichtenthaler (1999) proved that isopentenyl pyrophosphate (IPP) was synthesized in 1-deoxy-D-xylulose-5-phosphate (DOXP) pathway from pyruvate and glyceraldehyde. Phytoene synthase converts IPP to phytoene, a C40 compound. Oxygenic phototrops require three enzymes for the conversion of phytoene to lycopene. They are phytoene desaturase, δ-carotene desaturase, and cis-carotene isomerase. Bacteria use only phytoene desaturase for the conversion of phytoene to lycopene. Then lycopene is converted to β-carotene by lycopene cyclase (Wang et al., 2014). β-Carotene is hydroxylated by β-carotene hydroxylase to zeaxanthin (Takaichi, 2011).
Chemical Composition and Biochemistry of Sea Ice Microalgae
Published in Rita A. Horner, Sea Ice Biota, 1985
The chlorophyll c1-c2 containing species also possess β carotene and fucoxanthin as their major xanthophy 11s. These light harvesting pigments have similar absorption spectra and are efficient in transferring absorbed light energy to chlorophyll a.51 Their in vivo absorption maximum is in the blue region (450 to 550 nm),47 making them important in maximizing the absorption of under-ice irradiance. A similar function would be performed by peridinin in dinoflagellates, while in some members of the Prasinophyceae, absorption in the blue green region may be facilitated by the presence of siphonoxanthin.47 This xanthophyll is absent in the only member of the Prasinophyceae (Pyramimonas gelidicola) so far examined from the ice.52 In addition to these pigments which have shown a light harvesting function, most of the microalgae contain a number of xanthophyll pigments. The distribution of xanthophy 11s in ice diatoms is variable, with diatoxanthin and diadinoxanthin being the main nonlight harvesting carotenoids in some, but not all, species.52,53 Ratios of total carotenoids to chlorophyll a ranged from 1.12 to 1.4 in bottom ice diatoms from McMurdo sound (2°C and 24 µE m−2 sec−1).4 Higher values (1.6 to 2.2) were found in a natural population of Navicula glaciei Van Heurck sampled during early spring when in situ irradiances were very low.54 The structure and distribution of algal carotenoids has been discussed by Goodwin.55,56
Isolation and characterisation of monoclonal picocyanobacterial strains from contrasting New Zealand lakes
Published in Inland Waters, 2022
Lena A. Schallenberg, Susanna A. Wood, Jonathan Puddick, Pedro J. Cabello-Yeves, Carolyn W. Burns
A 5-point mixed standard curve (0.5–20 µg mL−1) of alpha-carotene (α-carotene; CaroteNature, Münsingen, Switzerland), beta-carotene (β-carotene; CaroteNature), chlorophyll a (Chl-a; Sigma-Aldrich, St. Louis, MO, USA), chlorophyll b (Chl-b; Sigma-Aldrich), and lutein (CaroteNature) was analysed with each HPLC run along with qualitative standards for each pigment analysed. Standards were calibrated by spectrophotometry at 448 nm (α-carotene), 454 nm (β-carotene), 664 nm (Chl-a), 647 nm (Chl-b), and 445 nm (lutein) using the extinction coefficients described in Roy et al. (2011). Equivalence factors for alloxanthin, canthaxanthin, diadinoxanthin, diatoxanthin, echinenone, fucoxanthin, myxoxanthophyll, peridinin, violaxanthin, and zeaxanthin were determined in relation to lutein by analysing standards at known concentrations alongside a lutein standard. These equivalence factors were used for the routine quantification of the other pigments rather than preparing a standard curve for each HPLC run (see Supplemental Table S1 for information on the HPLC-DAD analysis for each pigment measured).
Marked blue discoloration of late winter ice and water due to autumn blooms of cyanobacteria
Published in Lake and Reservoir Management, 2022
Heather A. Haig, Amir M. Chegoonian, John-Mark Davies, Deirdre Bateson, Peter R. Leavitt
Chl-a samples were analyzed using standard trichromatic methods (Jeffrey and Humphrey 1975), while high performance liquid chromatography (HPLC) was used to quantify changes in phytoplankton community composition (Leavitt and Hodgson 2001, Donald et al. 2013). Briefly, chlorophyll, carotenoid, and derivative pigments were extracted from POM on GF/C filters, dried under inert N2 gas, and redissolved into an injection solution before introduction into a fully calibrated Agilent Model 1100 HPLC fitted with photodiode array and fluorescence detectors. Lipid-soluble biomarker pigments (nmol pigment/L) were quantified for total phytoplankton abundance (Chl-a, pheophytin-a, β-carotene), siliceous algae (fucoxanthin), main diatoms (diatoxanthin, diadinoxanthin), cryptophytes (alloxanthin), dinoflagellates (peridinin), chlorophytes and cyanobacteria (lutein-zeaxanthin), chlorophytes alone (Chl-b), total cyanobacteria (echinenone), colonial cyanobacteria (myxoxanthophyll), Nostocales cyanobacteria (canthaxanthin), and potentially N2-fixing cyanobacteria (aphanizophyll) following Leavitt and Hodgson (2001). Ratios of concentrations of undegraded Chl-a to pheophytin-a (Chl-a:Pheo-a) were used to estimate phytoplankton vitality, as the latter compound is a Chl-a degradation product that is normally rare in living cells (Leavitt and Hodgson 2001).