Showing papers on "Neoxanthin published in 1994"

Iron deficiency-induced changes in the photosynthetic pigment composition of field-grown pear (Pyrus communis L) leaves

Abstract: In this work we characterize the changes induced by iron deficiency in the pigment composition of pear (Pyrus communis L.) leaves grown under high light intensities in field conditions in Spain. Iron deficiency induced decreases in neoxanthin and β-carotene concomitantly with decreases in chlorophyll a, whereas lutein and carotenoids within the xanthophyll cycle were less affected. Iron deficiency caused major increases in the lutein/chlorophyll a and xanthophyll cycle pigments/chlorophyll a molar ratios. The chlorophyll a/chlorophyll b ratio increased in response to iron deficiency. The carotenoids within the xanthophyll cycle in iron-deficient and in iron-sufficient (control) leaves underwent epoxidations and de-epoxidations in response to ambient light conditions. In control leaves dark-adapted for several hours, most of the xanthophyll cycle pigment pool was in the epoxidated form vio-laxanthin, whereas iron-deficient leaves had significant amounts of zeaxanthin. Iron-deficient leaves also exhibited an increased non-photochemical quenching, supporting the possibility of a role for pigments within the xanthophyll cycle in photoprotection.

Xanthophyll cycle components and capacity for non-radiative energy dissipation in sun and shade leaves ofLigustrum ovalifolium exposed to conditions limiting photosynthesis

Abstract: The relationships between photosynthetic efficiency, non-radiative energy dissipation and carotenoid composition were studied in leaves ofLigustrum ovalifolium developed either under full sunlight or in the shade. Sun leaves contained a much greater pool of xanthophyll cycle components than shade leaves. The rate of non-radiative energy dissipation, measured as non-photochemical fluorescence quenching (NPQ), was strictly related to the deepoxidation state (DPS) of xanthophyll cycle components in both sun and shade leaves, indicating that zeaxanthin (Z) and antheraxanthin (A) are involved in the development of NPQ. Under extreme conditions of excessive energy, sun leaves showed higher maximum DPS than shade leaves. Therefore, sun leaves contained not only a greater pool of xanthophyll cycle components but also a higher proportion of violaxanthin (V) actually photoconvertible to A and Z, compared to shade leaves. Both these effects contributed to the higher NPQ in sun versus shade leaves. The amount of photoconvertible V was strongly related to chla/b ratio and inversely to leaf neoxanthin content. This evidence indicates that the amount of photoconvertible V may be dependent on the degree of thylakoid membrane appression and on the organization of chlorophyll-protein complexes, and possible explanations are discussed. Exposure to chilling temperatures caused a strong decline in the photon yield of photosynthesis and in the intrinsic efficiency of PS II photochemistry in sun leaves, but little effects in shade leaves. These effects were accompanied by increases in the pool of xanthophyll cycle components and in DPS, more pronounced in sun than in shade leaves. This corroborates the view that Z and A may play a photoprotective role under unfavorable conditions. In addition to the xanthophyll-related non-radiative energy dissipation, a slow relaxing component of NPQ, independent from A and Z concentrations, has been found in leaves exposed to low temperature and high light. This quenching component may be attributed either to other regulatory mechanism of PS II efficiency or to photoinactivation.

Internal Gradients of Chlorophyll and Carotenoid Pigments in Relation to Photoprotection in Thick Leaves of Plants With Crassulacean Acid Metabolism

Abstract: Studies of two species of Crassulacean acid metabolism (CAM) succulent, Cotyledon orbiculata and Cotyledon paniculata reveal external and internal mechanisms of protection against photoinhibitory damage. Both species have thick leaves (up to 8 mm) in which chlorophyll extends throughout the leaf, being somewhat more concentrated towards the outer layers. Epidermal wax on C. orbiculata, which is produced in response to bright light during growth, reflects up to 60% of the incident light and creates a shaded environment within the leaf. These leaves have a low carotenoid/chlorophyll ratio and relatively low levels of the xanthophyll cycle pigments, two of which, antheraxanthin and zeaxanthin, are thought to be involved in controlled dissipation of excess energy and therefore in photoprotection. Under growth irradiance (1300 μmol m-2 s-1) little antheraxanthin or zeaxanthin is found in the epidermal layers and there is none in the interior. However, when the wax is removed by brushing, antheraxanthin and zeaxanthin are found throughout the leaf. In contrast C. paniculata has low reflectivity and is a typical sun plant with a much higher carotenoid/chlorophyll ratio concentrated towards the upper epidermis. In both species the xanthophyll cycle pigments are concentrated towards the exposed surfaces of the leaf, whereas, lutein, β-carotene and neoxanthin are more evenly distributed. Changes in the relative concentrations of the xanthophyll cycle pigments throughout the leaf, measured at various light intensities, show that antheraxanthin and zeaxanthin are always greater at the exposed surfaces and decline towards the centre of the tissue. These results show that variations in the capacity for photoprotection correspond closely with gradients in the light environment within the leaf.

Mechanism and Kinetics of Carotenoid Degradation during the Processing of Green Table Olives

Abstract: The only carotenoids that were transformed during lactic fermentation in green table olives were those whose molecular structure made them sensitive to the acid medium. The kinetic model that describes the transformation of these xanthophylls with 5,6-epoxide groups, violaxanthin and neoxanthin, into their corresponding 5,8-furanoid derivatives, auroxanthin and neochrome, (its first-order kinetics with respect to pigment concentration. The constancy of the overall carotenoid content throughout processing demonstrated the absence of other types of oxidative reactions that degrade them to colorless products

HPLC and SFC of carotenoids: Scope and limitations

Abstract: Today HPLC is an indispensable analytical method in carotenoid research. Different systems for the separation of carotenes, hydroxycarotenoids (luteidzeaxanthin; violaxanthid neoxanthin), EIZ isomers and optical isomers are discussed. Minimum criteria for the proper identification of a carotenoid are postulated. The application of SFC to the separation of carotenoids is reviewed and it is shown that this method is generally of less importance in the carotenoid field.

Major carotenoids in juices of Ponkan mandarin and Liucheng orange

Abstract: The identification and quantitation of major carotenoids in juices of Ponkan mandarin and Liucheng orange and their changes during harvesting were studied. Neoxanthin, violaxanthin, lutein, β-cryptoxanthin, α-carotene and β-carotene are the major carotenoids for Ponkan mandarin. During the harvesting period, the contents of violaxanthin, β-cryptoxanthin and β-carotene increase significantly. For Liucheng orange, neoxanthin, violaxanthin, lutein, antheraxanthin, β-cryptoxanthin, α-carotene and β-carotene are the major carotenoids. Among them, neoxanthin, violaxanthin, lutein, antheraxanthin and β-cryptoxanthin increase significantly during the harvesting period. The β-cryptoxanthin and β-carotene are the major contributors to the color of Ponkan mandarin juice while neoxanthin, violaxanthin, lutein and antheraxanthin are the major ones for the color of Liucheng orange juice.

Carotenoids in the eyespot apparatus of the flagellate green alga Spermatozopsis similis: Adaptation to the retinal-based photoreceptor

Abstract: Isolated intact eyespot apparatuses, the photoreceptive organelles involved in blue-light-mediated photoresponses of flagellate green algae, were analyzed regarding their carotenoid composition. Carotenoids from the eyespot apparatuses of Spermatozopsis similis were identified by high-performance liquid chromatography, visible-light absorption spectra, mass spectroscopy and by 1H-nuclear magnetic resonance spectroscopy (carotenes), and compared with those of whole-cell extracts. Both extracts contained β,β-carotene, β,ψ-carotene (formerly γ-carotene), lycopene, lutein, zeaxanthin, violaxanthin and all-E-and 9′-Z-neoxanthin. The relative carotenoid compositions, however, differed significantly. A twofold relative increase in the total carotene level was evident in the fraction enriched in eyespot apparatuses. This was mainly due to an increase in the monocyclic β,ψ-carotene and the aliphatic lycopene, whereas the relative content of β,β-carotene remained unchanged. On the other hand a relative decrease in the total xanthophyll content, especially of lutein and the epoxidic carotenoid neoxanthin, was observed in the eyespot apparatuses compared with the whole-cell extracts. The decrease of the latter resulted almost solely from a reduction of the 9′-Z-rather than the all-E-isomer. The bulk of the carotenes is thought to be localized in the highly organized eyespot lipid globules, which act as a combined quarter-wave interference reflector and absorption screen for the photoreceptor in green algae. The enrichment of β,ψ-carotene and lycopene in the eyespot apparatuses, extending the range of visible light absorption to longer wavelengths, represents an adaptation of the screen to the retinal-based photoreceptor of flagellate green algae and is one of the prerequisites for maximal directional sensitivity of the eyespot apparatus.

Immunological Evidence for the Binding of β-Carotene and Xanthophylls onto Peptides of Photosystem I from Nicotiana tabacum

Abstract: Photosystem I preparations were obtained from wild type tobacco Nicotiana tabacum var. John William’s Broadleaf (JWB) and from the two chlorophyll-deficient mutants N. tabacum Su/su and N. tabacum Su/su var. Aurea. The preparations were characterized with respect to the chlorophyll a/b ratio, their photosynthetic activity and their absorption spectroscopic properties. Peptides from these preparations were analyzed by SDS polyacrylamide gel electrophoresis and transferred for the detection of bound carotenoids according to the Western blot procedure to nitrocellulose or Immobilon membranes. The PS I preparation from the wild type JWB consisted of the core and the LHCP complex. The core complex contains the two core peptides with the same apparent MW of 66 kDa and several peptides with the lesser molecular masses of 22, 20, 19, 17, 16, 10 and 9 kDa. The light-harvesting protein complex consists of 4 subunits with the molecular masses 28, 26, 25 and 24 kDa. The PS I preparations of the yellow-green mutant Su/su and of the Aurea mutant Su/su var. Aurea contain as impurity traces of the D1 and D2 core peptides of photosystem II and also traces of the chlorophyll-binding photosystem II peptides with the molecular masses 42 and 47 kDa. The peptides of the photosystem I preparation were characterized by specific photosystem I antisera: An antiserum to the photosystem I complex reacts in the Western blot only with the homologous peptides of photosystem I. In comparative analyses with photosystem II preparations this antiserum (directed to photosystem I) reacts, as expected, only with the peptides of the light-harvesting complex. An antiserum to the CP 1 core peptides reacts only with the 66 kDa peptides of photosystem I and gives no cross reaction with heterodimer forms of the D1/D2 core peptides of photosystem II. In the Western blot procedure by means of polyclonal monospecific antisera to carotenoids it was demonstrated that β-carotene is bound in high concentration onto the core peptides CP 1 and to a lesser extent onto the two larger subunits of the LHCP complex, exhibiting the molecular masses of 28 and 26 kDa. Neoxanthin is bound onto the same peptides. In contrast to this, lutein was only identified on the core peptides CP 1 and violaxanthin only on the larger subunits of the LHCP complex. As the carotenoids are labelled with antibodies, even after SDS treatment in the electrophoresis, it is assumed, that the carotenoids are covalently bound via the ionon ring to the respective peptide

HPLC and SFC of Carotenoids. Scope and Limitations.

Abstract: Today HPLC is an indispensable analytical method in carotenoid research. Different systems for the separation of carotenes, hydroxycarotenoids (luteidzeaxanthin; violaxanthid neoxanthin), EIZ isomers and optical isomers are discussed. Minimum criteria for the proper identification of a carotenoid are postulated. The application of SFC to the separation of carotenoids is reviewed and it is shown that this method is generally of less importance in the carotenoid field.

Carotenoid-containing extract having oxidation-resistant activity, its production and antioxidant

Abstract: PURPOSE:To obtain a new antioxidant suitable for foods, medicines and cosmetics and having high safety and excellent oxidation-resistant activity derived from nature. CONSTITUTION:This carotenoid-containing extract having excellent oxidation- resistant activity, alpha-carotene, lutein and neoxanthin are obtained from a protozoan which belongs to the genus Chlamydomonas and capable of producing carotenoid having oxidation-resistant activity [specific example: Chlamydomonas reinhardtii (ATCC-18798)].

Nuclear Mutations Affecting Chloroplastic Pigments of Photoperiod‐insensitive Barley

Abstract: Three photoperiod-sensitive spring barley cultivars (Hordeum vulgare L.) and three independently derived, single-gene, nuclear mutants expressing photoperiod insensitivity and extremely early heading time under short daylengths were investigated for chloroplastic pigment variation in three environments using reverse-phase high-performance liquid chromatography (HPLC) to account for differences in laminae colour. In a greenhouse, non-stress environment and in a full sunlight, high-temperature stress environment, no systematic differences were observed among pigments of the mutant-parent pairs. However, under 12 h of daily light (600 μE m 2sec−1) and stress temperatures (20/10°C, night/day) in a growth chamber, the three mutants appeared similar to each other in chlorotic appearance and laminae pigment contents, but differed from the three non -chlorotic parents, which were similar to each other. The mutants had less chlorophyll a and b, β-carotene, lutein, taraxanthin, violaxanthin, and neoxanthin but more zeaxanthin than their parents. When shaded, the mutants became less chlorotic. How phenotypic differences for heading time and perception of day-length might be related to altered chloroplast contents remains unclear. The single-gene mutants conferring photopenod insensitivity were more sensitive to photothermal stress than their photoperiod-sensitive counterparts and as a result, their zeaxanthin content increased but the level of other pigments decreased.

Investigations on carotenoids in lichens from Nothofagus forests along the precipitation gradient (North-Western Patagonia, Argentina)

Abstract: Carotenoids contents in 26 specimens of six different species of corticolous lichens, collected along precipitation gradients from Nothofagus forests, North-Western Patagonia have been investigated by means of column and thin-layer chromatography. The presence of the following carotenoids: α-carotene, β-carotene, β-cryptoxanthin, lutein, 3′-epilutein, zeaxanthin, lutein epoxide, antheraxanthin, hydroxyechinenone, canthaxanthin, α-doradexanthin, astaxanthin, violaxanthin, neoxanthin, luteoxanthin, mutatoxanthin, capsochrome and apo-6′-lycopenal. The total content of carotenoids ranged from 12.24 (Platismatia glauca) to 56.51% μg g−1 dry weight (Nephroma antarcticum var. antarcticum). The amount of precipitations does not effect significantly the occurrence and total content of respective carotenoids. Von sechs verschiedenen Arten von Rindenflechten, gesammelt in niederschlagsarmen Gebieten in Nothofagus-Waldern, Nordwestpatagonien, wurde an 26 Proben mittels Saulen- und Dunnschicht-Chromatographie der Gehalt an Karotinoiden untersucht. Folgende Karotinoide wurden nachgewiesen: α-carotene, β-cryptoxanthin, lutein, 3′-epilutein, zeaxanthin, lutein epoxide, antheraxanthin, hydroxyechinenone, canthaxanthin, α-doradexanthin, astaxanthin, violaxanthin, neoxanthin, luteoxanthin. mutatoxanthin, capsochrome and apo-6′-lycopenal. Der Gesamtgehalt an Karotinoiden bewegt sich zwischen 12.24 (Platismatia glauca) und 56.51 μg g−1 Trockengewicht (Nephroma antarcicum var. antarcticum). Der Fallungsbetrag gibt nicht significant das Vorkommen und den totalen Gehalt der betreffenden Karotinoiden wieder.