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1.
Genetic factors involved in the bioavailability of tomato carotenoids.
Desmarchelier, C, Landrier, JF, Borel, P
Current opinion in clinical nutrition and metabolic care. 2018;(6):489-497
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Abstract
PURPOSE OF REVIEW To provide an update on the genetic factors recently associated with the interindividual variability of tomato carotenoid bioavailability. RECENT FINDINGS Several clinical studies have demonstrated that the main carotenoids found in tomatoes (lycopene, phytoene, phytofluene, β-carotene, lutein) all display relatively large interindividual variabilities of their bioavailability, with coefficients of variations more than 70%. The bioavailability of the parent molecules, and the blood/tissue appearance of their metabolites, is modulated by numerous proteins, involved in intestinal absorption and metabolism, blood lipoprotein transport or tissue uptake. Several single nucleotide polymorphisms (SNPs) have been associated with the interindividual variability of lycopene, lutein and β-carotene bioavailability, with six genes consistently shared between the three carotenoids, and in particular one SNP in ELOVL fatty acid elongase 2. The effects of the genetic variants taken separately are relatively low, that is each variant is usually associated with only a few percentage of the variability but multivariate analyses suggest that the additive effect of several genetic variants can explain a significant fraction of tomato carotenoid bioavailability. SUMMARY Additional studies are needed to improve our knowledge of the genetic determinants of tomato carotenoid bioavailability but progress in this field could one day allow nutritionists to provide more personalized dietary recommendations.
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Assembling the thickest plant cell wall: exine development in Echinops (Asteraceae, Cynareae).
Gabarayeva, NI, Polevova, SV, Grigorjeva, VV, Blackmore, S
Planta. 2018;(2):323-346
Abstract
The exceptionally complex exine of Echinops, representing a significant investment of energy, develops from an elaborate glycocalyx which establishes, by self-assembly, a multi-layered system of micelles upon which sporopollenin polymerizes. We report on pollen development in two species of Echinops (Asteraceae, Cynareae) studied using transmission and scanning electron microscopy with an emphasis on the organisation and development of the massive sporoderm (maximum thickness 18 μm). The major events of exine deposition during the tetrad stage follow the now familiar sequence of self-assembling micellar mesophases and the subsequent incorporation of sporopollenin, observed here as: (1) spherical units with light cores; (2) columns of spherical units with dark cores; (3) large branched macromolecules arranged in a dendritic, three-dimensional network of long alveoli; and (4) alveoli with electron-transparent cores and dense walls. Later, (5) the primexine exhibits an elongated-alveolate pattern in which the alveoli have electron-dense cores and lighter exteriors. When (6) the thick inner columellae make contact with the outer primexine, sporopollenin accumulation in the cores of the primexine alveolae establishes continuity between the inner and outer columellae. In the free microspore stage, (7) the foot layer and first lamellae of the endexine appear (8). The endexine lamellae then increase in number and massive accumulation of sporopollenin occurs on all exine elements, making individual elements such as tectal spines, more pronounced. These and earlier findings, as well as experimental simulations of exine development, show that pollen wall morphogenesis involves a subtle interplay of gene-driven biological processes and physico-chemical factors offering abundant opportunities for the generation of complex, taxon-specific patterns.
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Supplementation with macular carotenoids reduces psychological stress, serum cortisol, and sub-optimal symptoms of physical and emotional health in young adults.
Stringham, NT, Holmes, PV, Stringham, JM
Nutritional neuroscience. 2018;(4):286-296
Abstract
PURPOSE Oxidative stress and systemic inflammation are the root cause of several deleterious effects of chronic psychological stress. We hypothesize that the antioxidant and anti-inflammatory capabilities of the macular carotenoids (MCs) lutein, zeaxanthin, and meso-zeaxanthin could, via daily supplementation, provide a dietary means of benefit. METHODS A total of 59 young healthy subjects participated in a 12-month, double-blind, placebo-controlled trial to evaluate the effects of MC supplementation on blood cortisol, psychological stress ratings, behavioural measures of mood, and symptoms of sub-optimal health. Subjects were randomly assigned to one of three groups: placebo, 13 mg, or 27 mg / day total MCs. All parameters were assessed at baseline, 6 months, and 12 months. Serum MCs were determined via HPLC, serum cortisol via ELISA, and macular pigment optical density (MPOD) via customized heterochromatic flicker photometry. Behavioural data were obtained via questionnaire. RESULTS Significant baseline correlations were found between MPOD and Beck anxiety scores (r = -0.28; P = 0.032), MPOD and Brief Symptom Inventory scores (r = 0.27; P = 0.037), and serum cortisol and psychological stress scores (r = 0.46; P < 0.001). Supplementation for 6 months improved psychological stress, serum cortisol, and measures of emotional and physical health (P < 0.05 for all), versus placebo. These outcomes were either maintained or improved further at 12 months. CONCLUSIONS Supplementation with the MCs significantly reduces stress, cortisol, and symptoms of sub-optimal emotional and physical health. Determining the basis for these effects, whether systemic or a more central (i.e. brain) is a question that warrants further study.
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[Efficacy of lycopene intake in primary prevention of prostate cancer: a systematic review of the literature and meta-analysis.].
Cataño, JG, Trujillo, CG, Caicedo, JI, Bravo-Balado, A, Robledo, D, Mariño-Alvarez, AM, Pedraza, A, Arcila, MJ, Plata, M
Archivos espanoles de urologia. 2018;(2):187-197
Abstract
OBJECTIVE To evaluate the efficacy of lycopene intake in primary prevention of prostate cancer (PCa). METHODS A systematic search of the literature was conducted in March 2015 and the articles published between the years 1990-2015 were reviewed. The following search terms were used: prostate cancer, prostatic neoplasm, lycopene, prevention, effectiveness and efficacy (MeSH). Publications including research in humans, written in English and whose texts were accessible were reviewed. The types of studies included were: clinical trials, cohort and case-control studies. We found 343 articles; of these, 27 were included in the systematic review. After the latter were rigorously analyzed, 23 were included in the meta-analysis using the pooled odds ratios (OR) and risk ratios (RR) of case-control and cohort studies, respectively, and their confidence intervals (95% CI), using random-effects models with Review Manager 5.2. RESULTS Out of the 27 articles included in the systematic review, 22 were case-control and 5 were cohort studies. For the case-control studies, the total number of patients with PCa was 13,999 and the total number of controls 22,028. Cohort studies included 187,417 patients and PCa was diagnosed in 8,619 of these. The metaanalysis determined an OR = 0.94 (IC 95% 0.89-1.00) and RR = 0.9 (IC 95% 0.85-0.95) of PCa related with lycopene and/or raw or cooked tomatoes intake. CONCLUSIONS Although our study found that there is a statistically significant inverse association between lycopene intake and PCa, the magnitude of this association is weak and comes solely from observational studies, which do not allow recommending its use as a standard of practice. High-quality randomized clinical trials are required to clarify current evidence.
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From carotenoids to strigolactones.
Jia, KP, Baz, L, Al-Babili, S
Journal of experimental botany. 2018;(9):2189-2204
Abstract
Strigolactones are phytohormones that regulate various plant developmental and adaptation processes. When released into soil, strigolactones act as chemical signals, attracting symbiotic arbuscular mycorrhizal fungi and inducing seed germination in root-parasitic weeds. Strigolactones are carotenoid derivatives, characterized by the presence of a butenolide ring that is connected by an enol ether bridge to a less conserved second moiety. Carotenoids are isopenoid pigments that differ in structure, number of conjugated double bonds, and stereoconfiguration. Genetic analysis and enzymatic studies have demonstrated that strigolactones originate from all-trans-β-carotene in a pathway that involves the all-trans-/9-cis-β-carotene isomerase DWARF27 and carotenoid cleavage dioxygenase 7 and 8 (CCD7, 8). The CCD7-mediated, regiospecific and stereospecific double-bond cleavage of 9-cis-β-carotene leads to a 9-cis-configured intermediate that is converted by CCD8 via a combination of reactions into the central metabolite carlactone. By catalyzing repeated oxygenation reactions that can be coupled to ring closure, CYP711 enzymes convert carlactone into tricyclic-ring-containing canonical and non-canonical strigolactones. Modifying enzymes, which are mostly unknown, further increase the diversity of strigolactones. This review explores carotenogenesis, provides an update on strigolactone biosynthesis, with emphasis on the substrate specificity and reactions catalyzed by the different enzymes, and describes the regulation of the biosynthetic pathway.
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Fruit-localized phytochromes regulate plastid biogenesis, starch synthesis, and carotenoid metabolism in tomato.
Ernesto Bianchetti, R, Silvestre Lira, B, Santos Monteiro, S, Demarco, D, Purgatto, E, Rothan, C, Rossi, M, Freschi, L
Journal of experimental botany. 2018;(15):3573-3586
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Abstract
Light signaling has long been reported to influence fruit biology, although the regulatory impact of fruit-localized photoreceptors on fruit development and metabolism remains unclear. Studies performed in phytochrome (PHY)-deficient tomato (Solanum lycopersicum) mutants suggest that SlPHYA, SlPHYB2, and to a lesser extent SlPHYB1 influence fruit development and ripening. By employing fruit-specific RNAi-mediated silencing of SlPHY genes, we demonstrated that fruit-localized SlPHYA and SlPHYB2 play contrasting roles in regulating plastid biogenesis and maturation in tomato. Our data revealed that fruit-localized SlPHYA, rather than SlPHYB1 or SlPHYB2, positively influences tomato plastid differentiation and division machinery via changes in both light and cytokinin signaling-related gene expression. Fruit-localized SlPHYA and SlPHYB2 were also shown to modulate sugar metabolism in early developing fruits via overlapping, yet distinct, mechanisms involving the co-ordinated transcriptional regulation of genes related to sink strength and starch biosynthesis. Fruit-specific SlPHY silencing also drastically altered the transcriptional profile of genes encoding light-repressor proteins and carotenoid-biosynthesis regulators, leading to reduced carotenoid biosynthesis during fruit ripening. Together, our data reveal the existence of an intricate PHY-hormonal interplay during fruit development and ripening, and provide conclusive evidence on the regulation of tomato quality by fruit-localized phytochromes.
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Carotenoid Metabolism in Plants: The Role of Plastids.
Sun, T, Yuan, H, Cao, H, Yazdani, M, Tadmor, Y, Li, L
Molecular plant. 2018;(1):58-74
Abstract
Carotenoids are indispensable to plants and critical in human diets. Plastids are the organelles for carotenoid biosynthesis and storage in plant cells. They exist in various types, which include proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. These plastids have dramatic differences in their capacity to synthesize and sequester carotenoids. Clearly, plastids play a central role in governing carotenogenic activity, carotenoid stability, and pigment diversity. Understanding of carotenoid metabolism and accumulation in various plastids expands our view on the multifaceted regulation of carotenogenesis and facilitates our efforts toward developing nutrient-enriched food crops. In this review, we provide a comprehensive overview of the impact of various types of plastids on carotenoid biosynthesis and accumulation, and discuss recent advances in our understanding of the regulatory control of carotenogenesis and metabolic engineering of carotenoids in light of plastid types in plants.
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Limited appearance of apocarotenoids is observed in plasma after consumption of tomato juices: a randomized human clinical trial.
Cooperstone, JL, Novotny, JA, Riedl, KM, Cichon, MJ, Francis, DM, Curley, RW, Schwartz, SJ, Harrison, EH
The American journal of clinical nutrition. 2018;(4):784-792
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Abstract
BACKGROUND Nonvitamin A apocarotenoids occur in foods. Some function as retinoic acid receptor antagonists in vitro, though it is unclear if apocarotenoids are absorbed or accumulate to levels needed to elicit biological function. OBJECTIVE The aim of this study was to quantify carotenoids and apocarotenoids (β-apo-8'-, -10'-, -12'-, and -14'-carotenal, apo-6'-, -8'-, -10'-, -12'-, and -14'-lycopenal, retinal, acycloretinal, β-apo-13-carotenone, and apo-13-lycopenone) in human plasma after controlled consumption of carotenoid-rich tomato juices. DESIGN Healthy subjects (n = 35) consumed a low-carotenoid diet for 2 wk, then consumed 360 mL of high-β-carotene tomato juice (30.4 mg of β-carotene, 34.5 μg total β-apocarotenoids/d), high-lycopene tomato juice (42.5 mg of lycopene, 119.2 μg total apolycopenoids/d), or a carotenoid-free control (cucumber juice) per day for 4 wk. Plasma was sampled at baseline (after washout) and after 2 and 4 wk, and analyzed for carotenoids and apocarotenoids using high-pressure liquid chromatography (HPLC) and HPLC-tandem mass spectrometry, respectively. The methods used to analyze the apocarotenoids had limits of detection of ∼ 100 pmol/L. RESULTS Apocarotenoids are present in tomato juices at 0.1-0.5% of the parent carotenoids. Plasma lycopene and β-carotene increased (P < 0.001) after consuming high-lycopene and β-carotene tomato juices, respectively, while retinol remained unchanged. β-Apo-13-carotenone was found in the blood of all subjects at every visit, although elevated (P < 0.001) after consuming β-carotene tomato juice for 4 wk (1.01 ± 0.27 nmol/L) compared with both baseline (0.37 ± 0.17 nmol/L) and control (0.46 ± 0.11 nmol/L). Apo-6'-lycopenal was detected or quantifiable in 29 subjects, while β-apo-10'- and 12'-carotenal were detected in 6 and 2 subjects, respectively. No other apolycopenoids or apocarotenoids were detected. CONCLUSIONS β-Apo-13-carotenone was the only apocarotenoid that was quantifiable in all subjects, and was elevated in those consuming high-β-carotene tomato juice. Levels were similar to previous reports of all-trans-retinoic acid. Other apocarotenoids are either poorly absorbed or rapidly metabolized or cleared, and so are absent or limited in blood. β-Apo-13-carotenone may form from vitamin A and its presence warrants further investigation. This trial was registered at clinicaltrials.gov as NCT02550483.
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Influence of Sorafenib, Sunitinib and Capecitabine on the Antioxidant Status of the Skin.
Fuss, H, Lademann, J, Jung, S
Anticancer research. 2018;(9):5283-5288
Abstract
BACKGROUND/AIM: The aim of the present study was to examine the effect of orally administered sorafenib (Nexavar®), sunitinib (Sutent®) and capecitabine (Xeloda®), which cause palmoplantar erythrodysesthesia (PPE), on the antioxidant status of the skin and the formation of free radicals. PATIENTS AND METHODS A total of 42 patients were enrolled, of which 36 (85%) completed the study. Overall, 19 received capecitabine (2,000-4,000 mg per day), 10 sunitinib (25-50 mg per day) and 7 sorafenib (400-800 mg per day). Cutaneous carotenoids as markers of the antioxidant status of the skin were measured 1 day before the first oral administration (Tbase) and at day 18 of treatment (T1). RESULTS The mean antioxidant concentrations increased significantly in patients treated with sunitinib from 3.99±1.01 to 4.68±1.32, p=0.047 and sorafenib from 4.83±0.74 to 5.3±0.78, p=0.007. Treatment with capecitabine did not significantly increase the mean antioxidant concentration. CONCLUSION Formation of free radicals may not be the underlying patho-mechanism of tyrosine kinase inhibitors (TKI)- and capecitabine-associated PPE.
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Fruit flesh volatile and carotenoid profile analysis within the Cucumis melo L. species reveals unexploited variability for future genetic breeding.
Esteras, C, Rambla, JL, Sánchez, G, López-Gresa, MP, González-Mas, MC, Fernández-Trujillo, JP, Bellés, JM, Granell, A, Picó, MB
Journal of the science of food and agriculture. 2018;(10):3915-3925
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Abstract
BACKGROUND Aroma profile and carotenoids content of melon flesh are two important aspects influencing the quality of this fruit that have been characterized using only selected genotypes. However, the extant variability of the whole species remains unknown. RESULTS A complete view of the volatile/carotenoid profiles of melon flesh was obtained analyzing 71 accessions, representing the whole diversity of the species. Gas chromatography-mass spectrometry and high-performance liquid chromatography were used to analyze 200 volatile compounds and five carotenoids. Genotypes were classified into two main clusters (high/low aroma), but with a large diversity of differential profiles within each cluster, consistent with the ripening behavior, flesh color and proposed evolutionary and breeding history of the different horticultural groups. CONCLUSION Our results highlight the huge amount of untapped aroma diversity of melon germplasm, especially of non-commercial types. Also, landraces with high nutritional value with regard to carotenoids have been identified. All this knowledge will encourage melon breeding, facilitating the selection of the genetic resources more appropriate to develop cultivars with new aromatic profiles or to minimize the impact of breeding on melon quality. The newly characterized sources provide the basis for further investigations into specific genes/alleles contributing to melon flesh quality. © 2018 Society of Chemical Industry.