The Xanthophylls of Tomatoes

Curl, Aimee L

doi:10.1111/j.1365-2621.1961.tb00777.x

Cited by 39 publications

(24 citation statements)

References 11 publications

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“…The presence of hydroxy phytoene and hydroxy lycopene (lycoxanthin) had been reported previously in tomato fruits (Curl, 1961;Fray et al, 1995), albeit this identification did not involve MS. The exact structure of these compounds, as well as their enzymatic versus nonenzymatic origin, deserves further investigation.…”

Section: Linear Xanthophyllsmentioning

confidence: 99%

Dissection of Tomato Lycopene Biosynthesis through Virus-Induced Gene Silencing

Falcone²,

et al. 2013

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Lycopene biosynthesis in tomato (Solanum lycopersicum) fruits has been proposed to proceed through a poly-cis pathway catalyzed by phytoene synthase (PSY), two desaturases (phytoene desaturase [PDS] and z-carotene desaturase [ZDS]), and two cis-trans isomerases (z-carotene isomerase [ZISO] and prolycopene isomerase [CrtISO]). The mechanism of action of these enzymes has been studied in Escherichia coli, but a systematic study of their in vivo function is lacking. We studied the function of nine candidate genes (PSY1, PSY2, PSY3, PDS, ZDS, ZISO, CrtISO, CrtISO-Like1, and CrtISO-Like2) using virus-induced gene silencing (VIGS) coupled to high-resolution liquid chromatography coupled with diode array detector and mass spectrometry, which allowed the identification and quantitation of 45 different carotenoid isomers, including linear xanthophylls. The data confirm the confinement of the VIGS signal to the silenced fruits and the similarity of the phenotypes of PSY1-and CrtISO-silenced fruits with those of the yellow flesh and tangerine mutants. Light was able to restore lycopene biosynthesis in ZISO-silenced fruits. Isomeric composition of fruits silenced at different metabolic steps suggested the existence of three functional units, comprising PSY1, PDS/ZISO, and ZDS/CrtISO, and responsible for the synthesis of 15-cis-phytoene, 9,9'-di-cis-z-carotene, and all-trans-lycopene, respectively. Silencing of a desaturase (PDS or ZDS) resulted in the induction of the isomerase in the same functional unit (ZISO or CrtISO, respectively). All-trans-z-carotene was detectable in nonsilenced fruits, greatly increased in ZDS-silenced ones, and disappeared in CrtISO-Like1-/CrtISO-Like2-silenced ones, suggesting the existence of a metabolic side branch, comprising this compound and initiated by the latter enzymes.Tomato (Solanum lycopersicum) is a member of the family Solanaceae. The large mutant collections and high-resolution genetic maps, together with its ease of transformation and simple diploid genetics, make tomato the best genetic model in the asterid clade (representing approximately 25% of all vascular plants) and a model system for fleshy fruit development.

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Section: Linear Xanthophyllsmentioning

confidence: 99%

Dissection of Tomato Lycopene Biosynthesis through Virus-Induced Gene Silencing

Falcone²,

et al. 2013

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“…Other carotenoids (α-carotene, β-carotene, lutein, and β-cryptoxanthin) are negligible (Curl, 1961). The amount of lycopene in fresh tomato fruits depends on variety, maturity, and the environmental conditions under which the fruit matured.…”

Section: A Lycopene In Tomato Fruitsmentioning

confidence: 99%

Lycopene in Tomatoes: Chemical and Physical Properties Affected by Food Processing

Shi¹,

Maguer²

2000

Critical Reviews in Food Science and Nutrition

732

494

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Lycopene is the pigment principally responsible for the characteristic deep-red color of ripe tomato fruits and tomato products. It has attracted attention due to its biological and physicochemical properties, especially related to its effects as a natural antioxidant. Although it has no provitamin A activity, lycopene does exhibit a physical quenching rate constant with singlet oxygen almost twice as high as that of beta-carotene. This makes its presence in the diet of considerable interest. Increasing clinical evidence supports the role of lycopene as a micronutrient with important health benefits, because it appears to provide protection against a broad range of epithelial cancers. Tomatoes and related tomato products are the major source of lycopene compounds, and are also considered an important source of carotenoids in the human diet. Undesirable degradation of lycopene not only affects the sensory quality of the final products, but also the health benefit of tomato-based foods for the human body. Lycopene in fresh tomato fruits occurs essentially in the all-trans configuration. The main causes of tomato lycopene degradation during processing are isomerization and oxidation. Isomerization converts all-trans isomers to cis-isomers due to additional energy input and results in an unstable, energy-rich station. Determination of the degree of lycopene isomerization during processing would provide a measure of the potential health benefits of tomato-based foods. Thermal processing (bleaching, retorting, and freezing processes) generally cause some loss of lycopene in tomato-based foods. Heat induces isomerization of the all-trans to cis forms. The cis-isomers increase with temperature and processing time. In general, dehydrated and powdered tomatoes have poor lycopene stability unless carefully processed and promptly placed in a hermetically sealed and inert atmosphere for storage. A significant increase in the cis-isomers with a simultaneous decrease in the all-trans isomers can be observed in the dehydrated tomato samples using the different dehydration methods. Frozen foods and heat-sterilized foods exhibit excellent lycopene stability throughout their normal temperature storage shelf life. Lycopene bioavailability (absorption) can be influenced by many factors. The bioavailability of cis-isomers in food is higher than that of all-trans isomers. Lycopene bioavailability in processed tomato products is higher than in unprocessed fresh tomatoes. The composition and structure of the food also have an impact on the bioavailability of lycopene and may affect the release of lycopene from the tomato tissue matrix. Food processing may improve lycopene bioavailability by breaking down cell walls, which weakens the bonding forces between lycopene and tissue matrix, thus making lycopene more accessible and enhancing the cis-isomerization. More information on lycopene bioavailability, however, is needed. The pharmacokinetic properties of lycopene remain particularly poorly understood. Further research on the bioavalabili...

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“…The activity of the respiratory electron transport system ( ETS ) was measured by a tctrazolium reduction technique ( Curl and Sandberg 1961;Packard 1969;Packard et al 1971) on material filtcrcd from lo-30 liters of scawatcr, using Gehnan type A glass filters. The assay was standardized by the method of Packard and Healy ( 1968)) although the absorbtivity method of Hirsch et al (1963) works equally well.…”

Section: Estimates Of Metabolic Activity Ets Activitymentioning

confidence: 99%

A Study of the Distribution and Activity of Microorganisms in Ocean Water1

Hobbie

Holm‐Hansen

Packard

et al. 1972

Limnology & Oceanography

117

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ABSTR4CTEstimates of living mass and respiratory rate were made by several methods on large water samples taken at several depths at each of two ocean stations. Total microbial biomass estimates based on ATP determinations gave reasonable results in relation to phytoplankton biomass, total particulate organic carbon, and total particulate volume as determined by an electronic particle counter.Respiratory rate estimates based on 0, uptake, electron transport system activity, and ATP were in moderately good agreement in surface water but diverged widely in deep water. Heterotrophic uptake of specific organic compounds seems to be related to numbers of active bacteria and not related to total microbial respiration.Photosynthetic rates and release of dissolved photosynthate are reported for both stations.

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The Xanthophylls of Tomatoes

Cited by 39 publications

References 11 publications

Dissection of Tomato Lycopene Biosynthesis through Virus-Induced Gene Silencing

Dissection of Tomato Lycopene Biosynthesis through Virus-Induced Gene Silencing

Lycopene in Tomatoes: Chemical and Physical Properties Affected by Food Processing

A Study of the Distribution and Activity of Microorganisms in Ocean Water1

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