Showing papers on "Neoxanthin published in 2009"

Lutein Accumulation in the Absence of Zeaxanthin Restores Nonphotochemical Quenching in the Arabidopsis thaliana npq1 Mutant

Abstract: Plants protect themselves from excess absorbed light energy through thermal dissipation, which is measured as nonphotochemical quenching of chlorophyll fluorescence (NPQ). The major component of NPQ, qE, is induced by high transthylakoid DpH in excess light and depends on the xanthophyll cycle, in which violaxanthin and antheraxanthin are deepoxidized to form zeaxanthin. To investigate the xanthophyll dependence of qE, we identified suppressor of zeaxanthinless1 (szl1) as a suppressor of the Arabidopsis thaliana npq1 mutant, which lacks zeaxanthin. szl1 npq1 plants have a partially restored qE but lack zeaxanthin and have low levels of violaxanthin, antheraxanthin, and neoxanthin. However, they accumulate more lutein and a-carotene than the wild type. szl1 contains a point mutation in the lycopene b-cyclase (LCYB) gene. Based on the pigment analysis, LCYB appears to be the major lycopene b-cyclase and is not involved in neoxanthin synthesis. The Lhcb4 (CP29) and Lhcb5 (CP26) protein levels are reduced by 50% in szl1 npq1 relative to the wild type, whereas other Lhcb proteins are present at wild-type levels. Analysis of carotenoid radical cation formation and leaf absorbance changes strongly suggest that the higher amount of lutein substitutes for zeaxanthin in qE, implying a direct role in qE, as well as a mechanism that is weakly sensitive to carotenoid structural properties.

Sun-shade patterns of leaf carotenoid composition in 86 species of neotropical forest plants

Abstract: A survey of photosynthetic pigments, including 86 species from 64 families, was conducted for leaves of neotropical vascular plants to study sun-shade patterns in carotenoid biosynthesis and occurrence of α-carotene (α-Car) and lutein epoxide (Lx). Under low light, leaves invested less in structural components and more in light harvesting, as manifested by low leaf dry mass per area (LMA) and enhanced mass-based accumulation of chlorophyll (Chl) and carotenoids, especially lutein and neoxanthin. Under high irradiance, LMA was greater and β-carotene (β-Car) and violaxanthin-cycle pool increased on a leaf area or Chl basis. The majority of plants contained α-Car in leaves, but the α- to β-Car ratio was always low in the sun, suggesting preference for β-Car in strong light. Shade and sun leaves had similar β,e-carotenoid contents per unit Chl, whereas sun leaves had more β,β-carotenoids than shade leaves. Accumulation of Lx in leaves was found to be widely distributed among taxa: >5 mmol mol Chl-1 in 20% of all species examined and >10 mmol mol Chl-1 in 10% of woody species. In Virola elongata (Benth.) Warb, having substantial Lx in both leaf types, the Lx cycle was operating on a daily basis although Lx restoration in the dark was delayed compared with violaxanthin restoration.

Carotenoid and tocopherol composition of leaves, buds, and flowers of Capparis spinosa grown wild in Tunisia.

Abstract: High-performance liquid chromatography was used to determine carotenoids (beta-carotene, lutein, neoxanthin, and violaxanthin) and tocopherols of leaves, buds, and flowers of Tunisian Capparis spinosa. This plant shows strong resistance to hard environmental conditions, and it is one of the most commonly found aromatics in the Mediterranean kitchen. In this study, the means of the total carotenoids were 3452.5 +/- 1639.4, 1002 +/- 518.5, and 342.7 +/- 187.9 microg/g fresh weight (FW) in leaves, buds, and flowers, respectively. Lutein accounts for the high content. Violaxanthin provided the lowest portion of the total carotenoids. The principal form of tocopherol detected in leaves was alpha-tocopherol (20.19 +/- 10 mg/100 g FW). In buds and flowers, there were both alpha- (49.12 +/- 17.48 and 28.68 +/- 9.13 mg/100 g FW, respectively) and gamma-tocopherol (48.13 +/- 15.08 and 27.8 +/- 16.01 mg/100 g FW, respectively). The combined content of pro-vitamin A and vitamin E in capers encourages researchers to more explore and find developments for this plant.

In vivo and in vitro differences in chloroplast functionality in the two north Atlantic sacoglossans (Gastropoda, Opisthobranchia) Placida dendritica and Elysia viridis

Abstract: The photosynthetic functionality in chloroplasts in the two sacoglossan molluscs Placida dendritica and Elysia viridis from the Trondheim fjord in Norway was studied. P. dendritica and E. viridis with no functional chloroplasts in their digestive system were introduced to the green macroalgae Codium fragile. Our results showed that P. dendritica was not able to retain functional (photosynthetic) chloroplasts. Transmission electron microscopy (TEM) showed that chloroplasts were directly digested when phagocytosed into the digestive cells. Four stages of chloroplast degradation were observed. A corresponding operational quantum yield of chl a fluorescence (ΦPSII ~ 0) indicated autofluorescence, and the presence of highly degraded chl a supported these observations. In contrast, E. viridis was able to retain functional chloroplasts. For this species it took only 1 week for the chloroplasts inside the digestive cells to acquire the same ΦPSII and light utilisation coefficient (α) as C. fragile kept under the same light conditions. Data for 8 days showed a 2–6-fold increase in the maximum photosynthetic rate (Pmax) and light saturation index (Ek) relative to C. fragile. This increase in available light was probably caused by a reduced package effect in the digestive gland of E. viridis relative to C. fragile, resulting in a partial photoacclimation response by reducing the turnover time of electrons (τ). Isolated pigments from C. fragile compared to E. viridis showed the same levels of photosynthetic pigments (chl a and b, neoxanthin, violaxanthin, siphonaxanthin, siphonein and β,e-carotene) relative to μg chl a (w:w), indicating that the chloroplasts in E. viridis did not synthesise any new pigments. After 73 days of starvation, it was estimated that chloroplasts in E. viridis were able to stay photosynthetic 5–9 months relative to the size of the slugs, corresponding to an RFC of level 8 (a retention ability to retain functional chloroplasts (RFC) for more than 3 months). The reduction in ΦPSII, Pmax and α as a function of time was caused by a reduction in chloroplast health and number (chloroplast thylakoid membranes and PSII are degraded). These observations therefore conclude that chloroplasts from C. fragile cannot divide or synthesise new pigments when retained by E. viridis, but are able to partially photoacclimate by decreasing τ as a response to more light. This study also points to the importance of siphonaxanthin and siphonein as chemotaxonomic markers for the identification of algal sources of functional chloroplasts.

Qualitative and quantitative differences in the carotenoid composition of yellow and red peppers determined by HPLC‐DAD‐MS

Abstract: The carotenoids of a yellow (F(1) Amanda hybrid) and a red (F(1) Magali hybrid) pepper (Capsicum annuum L.) at the ripe stage, marketed in Campinas, Brazil, were identified by the combined use of the chromatographic behavior, absorption spectra, and chemical reactions, confirmed by the mass spectra. HPLC was carried out with a Spherisorb ODS 2 (C18, monomeric, 3 microm, 4.6 x 150 mm) column and DAD and mass detector. The main carotenoids in the yellow pepper were violaxanthin (27.1-36.6 microg/g), lutein (5.3-9.3 microg/g), and beta-carotene (1.6-3.9 microg/g). Neoxanthin, (Z)-violaxanthin, (Z)-antheraxanthin, (Z)-lutein, alpha-cryptoxanthin, beta-cryptoxanthin, zeta-carotene, alpha-carotene, and phytofluene were also found as minor carotenoids. In red pepper, the major carotenoids were capsanthin (29.2-36.2 microg/g), lutein (5.8-8.7 microg/g), beta-carotene (5.1-6.8 microg/g), and violaxanthin (1.8-3.6 microg/g). Minor carotenoids were capsorubin, beta-apo-8'-carotenal, antheraxanthin, zeaxanthin, and beta-cryptoxanthin.

Biochemistry and genetics of carotenoid composition in potato tubers

Abstract: ii

Importance of Genotype on Carotenoid and Chlorophyll Levels in Broccoli Heads

Abstract: Carotenoidsaresecondaryplantmetabolites invegetablesknowntobeessential in the human diet and reported to confer various positive health-promoting effects when consumed.BrassicaoleraceaL.vegetables likekale,cabbage,andbroccoliarerecognized as excellent sources of dietary carotenoids. Broccoli has emerged as the most important B. oleracea crop in the United States and it likely supplies more carotenoids to the U.S. diet than the other crops of this species. However, very little is known about the general carotenoid profile of this important vegetable or the levels of specific carotenoids and how they might vary among genotypes. Thus, the objectives of this study were to assess carotenoid profiles of different inbred broccoli heads; to assess chlorophyll concen- trations measured simultaneously during carotenoid assays; to determine the relative effects of genotype versus environment in influencing head carotenoid levels; and to examinephenotypic correlations betweencarotenoidlevelsandothertraits.Resultsshow lutein to be the most abundant carotenoid in broccoli heads ranging from 65.3 to 139.6 mgg -1 dry mass (DM) among nine inbreds tested in three environments. Genotype had a highly significant effect on lutein levels in broccoli heads and the ratio of s 2 g/s 2 p for this carotenoid was 0.84. Violaxanthin also exhibited a significant genotype effect, but it was found at lower levels (17.9 to 35.4 mgg -1 DM) than lutein. b-carotene and neoxanthin were detected at levels similar to violaxanthin, but genotypic differences were not detected when all environments were compared. This was also true for antheraxanthin, which was detectable in all genotypes at lower levels (mean of 13.3 mgg -1 DM) than the other carotenoids. Significant genotypic differences were observed for both chlorophyll a and b among the studied inbreds; however, no environment or genotype-by-environment effects were observed with these compounds. Results indicated that most carotenoids measured were positively and significantly correlated with one another, indicating that higher levels of one carotenoid were typically associated with higher levels of others. This study emphasizes the relative importance of lutein in broccoli heads and the key role that genotype plays with this compound, ultimately indicating that breeding cultivars with increased levels of this particular carotenoid may be feasible.

Effect of temperature on the expression of genes related to the accumulation of chlorophylls and carotenoids in albino tea

Abstract: SummaryAlbino tea (Camellia sinensis) cultivars have white shoots and high concentrations of amino acids when grown at low temperatures. Albinism in tea shoots remains to be investigated. The effect of temperature on the accumulation of chlorophylls and xanthophyll-cycle pigments, and on the expression of related genes in the albino tea cultivar ‘Xiaoxueya’ were investigated and compared to a common green tea cultivar, ‘Fudingdabai’. The concentrations of chlorophylls a and b, neoxanthin, violaxanthin, xanthophyll, and -carotene in ‘Xiaoxueya’ decreased markedly at 15oC, compared to their values at 20oC and 25oC. The expression of genes encoding chlorophyll a/b-binding protein (lhcb), rubisco activase (RCA), the D1 protein in the photosystem II core (psbA), terminal oxidase (TOX), and violaxanthin de-epoxidase (VDE) were suppressed in ‘Xiaoxueya’ tea leaves at 15oC.These changes led to slower rates of photosynthesis and leaf growth, and resulted in relatively high concentrations of amino acids in the albi...

Identification and Quantification of Major Carotenoids in Some Vegetables

Abstract: An HPLC study of 6 raw vegetables (Okra, green beans, eggplant zucchini, carrot and tomato) most frequently consumed worldwide was carried out to determine their carotenoid composition. The samples were purchased from supermarket in the city of Boston, USA. Neoxanthin, violaxanthin and lutein were contained in all samples except tomato for neoxanthin, carrot and tomato for violaxanthin and carrot for lutein. β-carotene was contained in all samples while α-carotene was contained only in carrot. Lycopene was contained in okra, green beans and tomato. Carrot had α-carotene and β-carotene as principal carotenoids and lutein as minor component. Relatively high ratios (9-cis to all-trans β-carotene) of above 0.2 g/g were noted in green beans, eggplant and okra.

Pigment profile in non-Spanish olive varieties ( Olea europaea L. Var. Coratina, Frantoio, and Koroneiki).

Abstract: The analysis, for the first time, of the chlorophyll and carotenoid profile of olive fruits of the varieties Coratina, Frantoio, and Koroneiki has revealed important differences with Spanish varieties. First, a high chlorophylls/carotenoids ratio and a low chlorophyll a/b ratio imply that the photosynthetic apparatus has structural differences with respect to other olive varieties; second, in the carotenoid fraction, a low percentage of lutein, a high percentage of β-carotene, and a high content in neoxanthin are signs that in these three olive varieties the carotenoid biosynthetic pathway is displaced, favoring the β,β series over the α,β series. These differences in the chlorophyll and carotenoid profiles of the fruit are reflected in the corresponding virgin olive oils. It is proposed that the limits of the pigmentary parameters of authenticity of virgin olive oil previously established for the Spanish varieties be extended to obtain markers at a general level, independent of the geographical origin.

Structure and properties of 9'-cis neoxanthin carotenoid radicals by electron paramagnetic resonance measurements and density functional theory calculations: present in LHC II?

Abstract: The radical intermediates formed upon catalytic or photooxidation of the carotenoid 9'-cis neoxanthin inside MCM-41 molecular sieves were detected by pulsed Mims and Davies electron nuclear double resonance (ENDOR) spectroscopies and characterized by density functional theory (DFT) calculations. Mims ENDOR spectra (20 K) were simulated using the hyperfine coupling constants predicted by DFT, which showed that a mixture of carotenoid radical cations (Car(+)) and neutral radicals (#Car) is formed. The DFT relative energies of the neutral radicals formed by proton loss from the C5, C5', C9, C9', C13, and C13'-methyl groups of Car(+) showed that #Car(9') is energetically most favorable, while #Car(9), #Car(13), #Car(13'), #Car(5'), and #Car(5) are less favorable for formation by 2.6, 5.0, 5.1, 22.5, and 25.6 kcal/mol. No evidence for formation of #Car(5') and #Car(5) was observed in the EPR spectra, consistent with DFT calculations. The epoxy group at the prime end and the allene bond at the unprime end prevent protons loss at the C5 and C5'-methyl groups by reducing the conjugation so crucial for the neutral radical stability. Previous CV measurements for allene-substituted carotenoids show that once the radical cations are formed, proton loss is rapid. These examined properties and the known crystal structure of the light harvesting complex II (LHC II) suggest the absence of the neutral radicals of 9'-cis neoxanthin available for quenching the excited states of Chl, consistent with its observed nonquenching properties.

Simple functional analysis of key genes involved in astaxanthin biosynthesis using Arabidopsis cultured cells

Abstract: Although several biotechnological researchers have reported the production of useful carotenoids in transgenic plants, the acquirement of genetically stable transgenic plants and subsequent examinations for effects of transgenes on the plants require a lot of time and efforts. Here, we show a simple and efficient approach to evaluate key genes involved in carotenoid biosynthesis using Arabidopsis thaliana suspension-cultured cell line T87. A plasmid for the expression of six key-gene candidates for astaxanthin production was constructed and introduced into A. thaliana T87 cells via Agrobacterium-mediated transformation. Five among twenty transgenic cell lines were isolated as lines resistant to a breaching herbicide norflurazon, and the expression of all the six transgenes in the lines was confirmed by quantitative transcriptional analysis. These five transgenic cell lines were shown to accumulate 4.3 to 21.9 μg g−1 fresh weight of astaxanthin, in addition to other ketocarotenoids containing adonirubin, canthaxanthin, echinenone and 3′-hydroxyechinenone. The amount of the ketocarotenoids was estimated to be 36% to 53% of the total carotenoids. The total carotenoid amount was also increased to 4.7 to 13.9 times that of control cells. We further employed microarray analysis to evaluate effects of the transgenes on endogenous gene expression in the transgenic cells. Transcriptional levels of many endogenous carotenogenic genes, e.g., genes for β-carotene hydroxylase, neoxanthin cleavage enzymes, abscisic aldehyde oxidase, 1-deoxy-D-xylulose 5-phosphate synthase, endoplasmic reticulum-targeted and mitochondria-targeted geranyl-geranyl diphosphate synthase were significantly elevated by the expression of the six genes for astaxanthin biosynthesis. These data suggest that transgenic cells adjust their whole cellular isoprenoid-metabolic system to direct the high-level production of the carotenoids including the ketocarotenoids in the plastids.

Influence of Cold Hardening on Chlorophyll and Carotenoid in Chlorella vulgaris

Abstract: Chlorella vulgaris C-27 has developed freezing tolerance by hardening at 3 oC for 24 hour. It was reported that many genes which encode proteins related stress response, storage, protein synthesis and metabolism including ζ-carotene desaturase increase at transcriptional levels. We focus on the change of photosynthesis pigments, and assessed the effects of the cold acclimation on chlorophyll and carotenoid in the hardened and unhardened cells of C. vulgaris C-27 and C. vulgaris C-102 (a chilling-sensitive strain). Cold hardening at 3 oC for 24 hour caused a slight reduce of the chlorophyll content in C. vulgaris C-27, but did a significant reduction of that in C. vulgaris C-102. In chlorella cells, six major carotenoids, i.e., β-carotene, α-carotene, lutein, zeaxanthin, violaxanthin and neoxanthin, were detected by an original method for carotenoid determination of C. vulgaris C-27 and C. vulgaris C-102. It was possible to sepa- rate lutein and zeaxanthin by HPLC using cholester column. The carotenoid composition was highly influ- enced by the cold hardening. It was elucidated that total carotenoid was little affected by hardening at 3 oC, but zeaxanthin content increased with decrease of violaxanthin content. On the other hand, incubation at 25 oC after freeze-thaw restored the altered levels of both pigments to pre-hardening levels. This result suggests that freezing tolerance of C. vulgaris C-27 induced during cold acclimation have a close involve- ment of change in xanthophyll cycle which plays a significant role to relieve oxidative stress at freezing and thawing.