Showing papers on "Neoxanthin published in 1997"
07 Feb 1997
TL;DR: In this paper, a total of 22 species of vegetables and 28 species of fruit (including rhubarb) were analyzed for their contents of carotenoids by reversed-phase HPLC and photodiode array detection.
Abstract: Epidemiological studies have shown inverse correlations between the consumption of vegetables and fruit rich in carotenoids and the incidence of cancer and cardiovascular diseases. A total of 22 species of vegetables (including potatoes) and 28 of fruit (including rhubarb) were analysed for their contents of carotenoids by reversed-phase high-performance liquid chromatography (RP-HPLC) and photodiode array detection. A total of 27 carotenoids (among them β-carotene, lutein and violaxanthin also as cis isomers) were identified and quantified. Lutein, β-carotene (trans and cis forms) and violaxanthin were the predominant carotenoids in all green vegetables. Yellow and yellow-red vegetables and fruit contained β-carotene, α-carotene, β-cryptoxanthin and α-cryptoxanthin. Antheraxanthin and neoxanthin were found in nearly all produce. Lycopene was the predominant carotene in tomatoes, papayas and grapefruit. Vegetables with more than 10 mg of total carotenoids per 100-g edible portion were kale (34.8), red paprika (30.4), parsley (25.7), spinach (17.3), lamb’s lettuce (16.0), carrots (15.9) and tomatoes (12.7). In the case of fruit, grapefruit (3.5), papayas (3.4) and nectarines (2.4) were pre-eminent with more than 2 mg of total carotenoids (except for phytoene, phytofluene and ζ-carotene) per 100 g.
194 citations
TL;DR: The results imply predominant energy transfer from the central Ls to Chl b which requires a modification of the currently accepted arrangement of Chl pigments in LHC II.
Abstract: Singlet energy transfer between the carotenoids (Cars) and chlorophylls (Chls) in the light-harvesting complex II (LHC II) from higher plants has been studied using ultrafast transient absorption spectroscopy by exciting the Cars directly in the 475-515 nm wavelength range. LHC II trimers from Arabidopsis thaliana with well-defined Car compositions have been used. From HPLC, the wild type (WT) monomer contains two luteins (Ls), one neoxanthin (N), and a trace of violaxanthin (V) per 12 Chls. The ABA-3 mutant contains 1.4 Ls and 0.6 zeaxanthin (Z) per monomer. Though exploitation of the difference in Car constitution and exciting the WT at 475 and 490 nm, and the ABA-3 mutant at 490 and 515 nm, the different Car contributions to energy transfer have been probed. Evidence for energy transfer mainly from the Car to Chl b is observed in the WT. In the mutant, additional transfer from Car to Chl a correlates with the presence of Z. The results imply predominant energy transfer from the central Ls to Chl b which requires a modification of the currently accepted arrangement of Chl pigments in LHC II.
123 citations
TL;DR: In this article, carotenoids were identified in mango cultivar Keitt by means of HPLC data (retention time, co-injection, and chemical reactions).
Abstract: β-Carotene (all-trans), β-cryptoxanthin (all-trans and cis), zeaxanthin (all-trans), luteoxanthin isomers, violaxanthin (all-trans and cis), and neoxanthin (all-trans and cis) were identified in mango cultivar Keitt by means of HPLC data (retention time, co-injection, and chemical reactions). Mass spectrometry (molecular ion, fragmentation pattern, m/z relative intensity) confirmed the identity of these carotenoids (not the geometric form); additionally, lutein and mutatochrome were detected when a large amount of sample was utilized. The quantitative composition was determined by HPLC, Sudan I being used as internal standard. all-trans-Violaxanthin (21.1 ± 2.9 μg/g), all-trans-β-carotene (15.1 ± 1.5 μg/g), and a cis-violaxanthin (10.1 ± 0.2 μg/g), tentatively identified as 9-cis, were the principal carotenoids. Keywords: Mango carotenoids; HPLC; MS
120 citations
TL;DR: The results suggest that only a few of the zeaxanthin molecules present within the light-harvesting antenna of PSII may be involved in NPQ and neither the accumulation of a large pool of zexanthin within the antenna ofPSII nor an increase in conversion of violaxanth in to zeax anthin will necessarily enhance photoprotective energy dissipation.
Abstract: Abscisic acid (ABA)-deficient mutants of Arabidopsis do not synthesize the epoxy-xanthophylls antheraxanthin, violaxanthin, or neoxanthin. However, thylakoid membranes from these mutants contain 3-fold more zeaxanthin than wild-type plants. This increase in zeaxanthin occurs as a stoichiometric replacement of the missing violaxanthin and neoxanthin within the pigment-protein complexes of both photosystem I and photosystem II (PSII). The retention of zeaxanthin in the dark by ABA-deficient mutants sensitizes the leaves to the development of nonphotochemical quenching (NPQ) during the first 2 to 4 min following a dark-light transition. However, the increase in pool size does not result in any increase in steady-state NPQ. When we exposed wild-type and ABA-deficient mutants leaves to twice growth irradiance, the mutants developed lower maximal NPQ but suffered similar photoinhibition to wildtype, measured both as a decline in the ratio of variable to maximal fluorescence and as a loss of functional PSII centers from oxygen flash yield measurements. These results suggest that only a few of the zeaxanthin molecules present within the light-harvesting antenna of PSII may be involved in NPQ and neither the accumulation of a large pool of zeaxanthin within the antenna of PSII nor an increase in conversion of violaxanthin to zeaxanthin will necessarily enhance photoprotective energy dissipation.
101 citations
TL;DR: Results suggest that irradiance-acclimation of C. vitalba can occur regardless of N-supply, and under N limitation at high irradiance, a balance between light capture and photosynthetic capacity is important rather than an increase in xanthophyll cycle-dependent energy dissipation.
Abstract: Effects of nitrogen supply (N-supply) on the photosynthetic apparatus of Clematis vitalba L. grown at several irradiances were determined by measuring soluble protein content, rubisco activity, photosynthetic pigment content and composition, and the photochemical efficiency of photosystem II (Fv/Fm). Compared to low irradiance (3 and 10% full sunlight), leaves grown at higher irradiance (up to full sunlight) had up to 5–6 times the soluble protein content and rubisco activity, and up to 2–4 times the total carotenoid content, on both a leaf area and a chlorophyll basis. On a leaf area basis, decreased N-supply reduced soluble protein concentration, rubisco activity and total carotenoid concentration to a greater extent at high compared to low irradiance. On a chlorophyll basis, in contrast, soluble protein and rubisco activity decreased by over 40% with increased N-supply (1.0–0.1 mol m-3) at high irradiance but N-supply did not influence the concentration of total carotenoids. Leaves grown at high compared to low irradiance had a greater concentration of xanthophyll cycle pigments (V+A+Z), β-carotene and lutein (but not neoxanthin) on a chlorophyll basis, and a slightly lower Fv/Fm. Nitrogen- supply did not influence the composition of the photosynthetic pigment pool, Fv/Fm, or the extent of de-epoxidation of the V+A+Z pool. The results suggest that irradiance-acclimation of C. vitalba can occur regardless of N-supply. Under N limitation at high irradiance, a balance between light capture and photosynthetic capacity is important rather than an increase in xanthophyll cycle-dependent energy dissipation. The importance of lutein as a light-harvesting pigment is questioned. A rapid method for the reversed phase-HPLC separation of carotenoids is described.
71 citations
TL;DR: It is concluded that violaxanthin de-epoxidase converts violXanthin in the lipid matrix and not at the proteins, that violxanthin does not prefer one particular membrane region or one particular chlorophyll protein complex, and that the xanthophyll cycle pigments are oriented in a vertical manner in order to be accessible from both sides of the membrane when located in the cholesterol matrix.
Abstract: Using DTT and iodoacetamide as a novel irreversible method to inhibit endogenous violaxanthin de-epoxidase, we found that violaxanthin could be converted into zeaxanthin from both sides of the thylakoid membrane provided that purified violaxanthin de-epoxidase was added. The maximum conversion was the same from both sides of the membrane. Temperature was found to have a strong influence both on the rate and degree of maximal violaxanthin to zeaxanthin conversion. Thus only 50% conversion of violaxanthin was detected at 4 °C, whereas at 25 °C and 37 °C the degree of conversion was 70% and 80%, respectively. These results were obtained with isolated thylakoids from non-cold acclimated leafs. Pigment analysis of sub-thylakoid membrane domains showed that violaxanthin was evenly distributed between stroma lamellae and grana partitions. This was in contrast to chlorophyll a and β-carotene which were enriched in stroma lamellae fractions while chlorophyll b, lutein and neoxanthin were enriched in the grana membranes. In combination with added violaxanthin de-epoxidase we found almost the same degree of conversion of violaxanthin to zeaxanthin (73–78%) for different domains of the thylakoid membrane. We conclude that violaxanthin de-epoxidase converts violaxanthin in the lipid matrix and not at the proteins, that violaxanthin does not prefer one particular membrane region or one particular chlorophyll protein complex, and that the xanthophyll cycle pigments are oriented in a vertical manner in order to be accessible from both sides of the membrane when located in the lipid matrix.
48 citations
TL;DR: In this paper, the carotenoid (Car) triplet-triplet absorption band (ΔA>0) is red-shifted and broader than in trimers, and the features attributable to the perturbation of the Qy band of a chlorophyll a (Chla) by a nearby Car triplet are more pronounced, than those attributed to trimers.
47 citations
TL;DR: The results indicate that it is unlikely that the content and composition of carotenoids and the operation of the xanthophyll cycle are major factors in determining the better ability of chilling-tolerant genotypes, as compared to chilling-sensitive ones, to cope with low temperature-induced reductions in photosynthesis.
38 citations
TL;DR: The major light-harvesting complex of the prasinophycean alga Mantoniella squamata is unique compared to other chlorophyll a/b-binding LHC with respect to the primary protein structure and the pigmentation and 8 different xanthophylls were found in the LHC, which can be explained best in terms of an oligomeric, presumably trimeric LHC organisation with subunits of heterogeneous pigmentation.
Abstract: The major light-harvesting complex (LHC) of the prasinophycean alga Mantoniella squamata is unique compared to other chlorophyll (Chl) a/b-binding LHC with respect to the primary protein structure and the pigmentation. Although the presence of Chl a, Chl b, a Chl c-type pigment and the xanthophylls neoxanthin, violaxanthin and prasinoxanthin was clearly determined, several carotenoids remained unidentified or were described controversially. We re-analysed the carotenoid composition and identified a new set of xanthophylls present in the LHC: uriolide, micromonol, micromonal and dihydrolutein. Additionally, one hydrophobic component was detected, presumably a xanthophyll. The pigment analysis in combination with quantitative protein determinations revealed a pigment-protein stoichiometry of 6 Chl a, 6 Chl b, 2 Chl c* and about 2 prasinoxanthin molecules per polypeptide. The other xanthophylls were present in sub-stoichiometric amounts. A comparison of results from LHC isolated either by sucrose density centrifugation or SDS-polyacryl gel electrophoresis revealed a decline in the amount of prasinoxanthin and a loss of violaxanthin using the latter preparation procedure, while the stoichiometric ratios of the other 6 xanthophylls remained constant. The fact that 8 different xanthophylls were found in the LHC of M. squamata can be explained best in terms of an oligomeric, presumably trimeric LHC organisation with subunits of heterogeneous pigmentation. Especially, the very stable assembly of most of the minor xanthophylls led to the assumption that these components play an important role in stabilisation and probably also in trunerisation of the LHC in vivo.
21 citations
01 Jan 1997
TL;DR: In this article, the xanthophyll cycle was observed to operate in under-story leaves of several hardwood seedlings and shrubs grown under different light environments were analyzed for pigments and the operation of the cycle.
Abstract: Two and three years after the outplanting of 1-O northern red oak (Quercus rubra, NRO) and white oak (Q. ulba, WO) nursery stocks, the highest net photosynthetic rates (A-) were observed from seedlings growing on a clearcut site followed by those under a pine stand. Both NRO and WO seedlings under a hardwood stand had A, less than 10% of the full sun seedling A,,. Oaks grown under hardwoods increased their A,, more in response to sunflecks than those under a pine stand. Besides NRO and WO seedIings, leaves of several hardwood seedlings and shrubs grown under different light environments were analyzed for pigments and the operation of the xanthophyll cycle. All species investigated shared the following characteristics: higher contents of chlorophyll a+b, a-carotene, lutein, and neoxanthin; smaller xanthophyll cycle pool (sum of violaxanthin V, antheraxanthin A, and zeaxanthin Z); and lower ratios of Z+A to Z+A+V in leaves of understory plants than leaves of the same species growing in full sun. The diurnal xanthophyll cycle (i.e., high Z+A/Z+A+V ratio in midday and low Z+A/Z+A+V ratio near dawn and dusk) was present in leaves of NRO and WO seedlings on the clearcut site. Almost no xanthophyll cycle was operating in understory leaves except that upon sunflecking NRO and WO under hardwoods increased their Z+A/Z+A+V ratio. For every unit of the xanthophyll cycle pool, twice as many chlorophylis must be protected in shade-grown leaves as in sun-grown leaves. The potential use of leaf a-carotene levels in silviculture is discussed.
2 citations
TL;DR: In this article, the authors showed that during 14 days of Aleurites plants with 0.3 ppm SO₂ leads to quantitative modifications of the lipid composition of leaves, such that the ratio of phospholipids to glycolipids is shifted from 1:3 in control plants to 1:1.8 in SO-plants, which implies that not only the thylakoid membrane but also the mitochondrial membranes and cell membranes of tonoplasts and of the plasmalemma suffer modifications under the influence of SO.
Abstract: Gassing during 14 days of Aleurites plants with 0.3 ppm SO₂ leads to quantitative modifications of the lipid composition of leaves. The ratio of phospholipids to glycolipids is shifted from 1:3 in control plants to 1:1.8 in SO₂-plants. Glycolipids decrease from 62% of total lipids in control plants to 50% in SO₂-plants. On the other hand phospholipids increase from 20% in control plants to 28% of total lipids in SO₂-plants. This implies that not only the thylakoid membrane but also the mitochondrial membranes and cell membranes of tonoplasts and of the plasmalemma suffer modifications under the influence of SO₂. With respect to the fatty acid composition, despite the drastic change in the lipid composition no alteration in comparison to control plants is seen. Chlorophylls increase in SO₂-plants by 24% . Also the content of β-carotene, and of the xanthophylls lutein, violaxanthin and neoxanthin is increased. Only zeaxanthin exhibits a decrease. From the changes in the chlorophyll and carotenoid content it can be concluded that in SO₂-plants the light-harvesting-complex (LHCP) is stronger developed (P. He, A. Radunz, K. P. Bader and G. H. Schmid, Z. f. Naturforsch. 51c, 441- 453 and 833-840, 1996).