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Nature Communications Jul 2021Aurantinins (ARTs) are antibacterial polyketides featuring a unique 6/7/8/5-fused tetracyclic ring system and a triene side chain with a carboxyl terminus. Here we...
Aurantinins (ARTs) are antibacterial polyketides featuring a unique 6/7/8/5-fused tetracyclic ring system and a triene side chain with a carboxyl terminus. Here we identify the art gene cluster and dissect ART's C-methyl incorporation patterns to study its biosynthesis. During this process, an apparently redundant methyltransferase Art28 was characterized as a malonyl-acyl carrier protein O-methyltransferase, which represents an unusual on-line methyl esterification initiation strategy for polyketide biosynthesis. The methyl ester bond introduced by Art28 is kept until the last step of ART biosynthesis, in which it is hydrolyzed by Art9 to convert inactive ART 9B to active ART B. The cryptic reactions catalyzed by Art28 and Art9 represent a protecting group biosynthetic logic to render the ART carboxyl terminus inert to unwanted side reactions and to protect producing organisms from toxic ART intermediates. Further analyses revealed a wide distribution of this initiation strategy for polyketide biosynthesis in various bacteria.
Topics: Acyl Carrier Protein; Anti-Bacterial Agents; Bacillus subtilis; Bacterial Proteins; Biosynthetic Pathways; Esterification; Gram-Negative Bacteria; Gram-Positive Bacteria; Methyltransferases; Microbial Sensitivity Tests; Models, Chemical; Molecular Structure; Multigene Family; Polyenes; Polyketides
PubMed: 34301953
DOI: 10.1038/s41467-021-24846-7 -
Public Health Nutrition May 2021The purpose of the study was to examine the association between dietary lutein and zeaxanthin (L + Z) intake and immediate word recall (IWR) and delayed word recall...
OBJECTIVE
The purpose of the study was to examine the association between dietary lutein and zeaxanthin (L + Z) intake and immediate word recall (IWR) and delayed word recall (DWR), and to identify the major contributors to dietary L + Z intake in a recent and representative sample of the older US population.
DESIGN
In this cross-sectional analysis, multivariate path analytic models estimated the association between L + Z consumption and cognitive performance while adjusting for covariates.
SETTING
Observations were drawn from the 2014 Health and Retirement Study, a nationally representative panel study of older US adults, and the 2013 Health Care and Nutrition Study, which assessed dietary intake via FFQ in a subsample of respondents.
PARTICIPANTS
The analytic sample included 6390 respondents aged ≥50 years.
RESULTS
L + Z intake was 2·44 ± 2·32 mg/d on average, and L + Z intake differed significantly across quartiles (P < 0·001). For example, average L + Z intake in Q1 was 0·74 ± 0·23 mg/d and in Q4 was 5·46 ± 2·88 mg/d. In covariate adjusted models, older adults in the highest quartiles of L + Z intake had significantly greater IWR and DWR scores than those in the lowest quartile. Leafy vegetables, cruciferous vegetables, dark yellow vegetables, fish and seafood, legumes, eggs and fruit were significant and meaningful predictors of dietary L + Z intake.
CONCLUSION
A high consumption of vegetables, fish and seafood, legumes, eggs and fruit is associated with a higher intake of L + Z and greater word recall among older adults.
Topics: Adult; Aged; Animals; Cross-Sectional Studies; Diet; Humans; Lutein; Memory, Short-Term; Middle Aged; Zeaxanthins
PubMed: 32349832
DOI: 10.1017/S1368980019005020 -
Journal of Lipid Research 2021Driven by the energy of a photon, the visual pigments in rod and cone photoreceptor cells isomerize 11-cis-retinal to the all-trans configuration. This photochemical... (Review)
Review
Driven by the energy of a photon, the visual pigments in rod and cone photoreceptor cells isomerize 11-cis-retinal to the all-trans configuration. This photochemical reaction initiates the signal transduction pathway that eventually leads to the transmission of a visual signal to the brain and leaves the opsins insensitive to further light stimulation. For the eye to restore light sensitivity, opsins require recharging with 11-cis-retinal. This trans-cis back conversion is achieved through a series of enzymatic reactions composing the retinoid (visual) cycle. Although it is evident that the classical retinoid cycle is critical for vision, the existence of an adjunct pathway for 11-cis-retinal regeneration has been debated for many years. Retinal pigment epithelium (RPE)-retinal G protein-coupled receptor (RGR) has been identified previously as a mammalian retinaldehyde photoisomerase homologous to retinochrome found in invertebrates. Using pharmacological, genetic, and biochemical approaches, researchers have now established the physiological relevance of the RGR in 11-cis-retinal regeneration. The photoisomerase activity of RGR in the RPE and Müller glia explains how the eye can remain responsive in daylight. In this review, we will focus on retinoid metabolism in the eye and visual chromophore regeneration mediated by RGR.
Topics: Retinaldehyde
PubMed: 32493732
DOI: 10.1194/jlr.TR120000850 -
Communications Biology Oct 2023Various species of ascomycete fungi synthesize the carboxylic carotenoid neurosporaxanthin. The unique chemical structure of this xanthophyll reveals that: (1) Its...
Various species of ascomycete fungi synthesize the carboxylic carotenoid neurosporaxanthin. The unique chemical structure of this xanthophyll reveals that: (1) Its carboxylic end and shorter length increase the polarity of neurosporaxanthin in comparison to other carotenoids, and (2) it contains an unsubstituted β-ionone ring, conferring the potential to form vitamin A. Previously, neurosporaxanthin production was optimized in Fusarium fujikuroi, which allowed us to characterize its antioxidant properties in in vitro assays. In this study, we assessed the bioavailability of neurosporaxanthin compared to other provitamin A carotenoids in mice and examined whether it can be cleaved by the two carotenoid-cleaving enzymes: β-carotene-oxygenase 1 (BCO1) and 2 (BCO2). Using Bco1Bco2 mice, we report that neurosporaxanthin displays greater bioavailability than β-carotene and β-cryptoxanthin, as evidenced by higher accumulation and decreased fecal elimination. Enzymatic assays with purified BCO1 and BCO2, together with feeding studies in wild-type, Bco1, Bco2, and Bco1Bco2 mice, revealed that neurosporaxanthin is a substrate for either carotenoid-cleaving enzyme. Wild-type mice fed neurosporaxanthin displayed comparable amounts of vitamin A to those fed β-carotene. Together, our study unveils neurosporaxanthin as a highly bioavailable fungal carotenoid with provitamin A activity, highlighting its potential as a novel food additive.
Topics: Mice; Animals; beta Carotene; Provitamins; Vitamin A; Biological Availability; Carotenoids; Dioxygenases
PubMed: 37864015
DOI: 10.1038/s42003-023-05446-1 -
The Journal of Nutrition Oct 2023Carotenoids are plant pigments with light filtering and antioxidant properties that deposit in human tissues, including retina and skin. Descriptive characteristics and...
BACKGROUND
Carotenoids are plant pigments with light filtering and antioxidant properties that deposit in human tissues, including retina and skin. Descriptive characteristics and covariates of carotenoid status in macula and skin have been examined in adults; however, similar studies in children are limited. Thus, this study aimed to delineate how factors of age, sex, race, weight status, and dietary carotenoid intake relate to macular and skin carotenoids in children.
METHODS
Children (7-13 y, N = 375) completed heterochromatic flicker photometry to assess macular pigment optical density (MPOD). Participants underwent anthropometrics to measure weight status (BMI percentile [BMI%]), and parent/guardian provided demographic information. Subsample data were available for skin carotenoids (N = 181), assessed using reflection spectroscopy, and dietary carotenoids (N = 101) using the Block Food Frequency Questionnaire. Relationships between skin and macular carotenoids were assessed using partial Pearson's correlations controlling for age, sex, race, and BMI%. Relationships between dietary carotenoids and macular and skin carotenoids were assessed using stepwise linear regression including age, sex, race, and BMI% in the model.
RESULTS
Mean MPOD was 0.56 ± 0.22 and skin carotenoid score was 282 ± 94.6. There was no significant correlation between MPOD and skin carotenoids (r = 0.02, P = 0.76). BMI% was negatively associated with skin (stdβ = -0.42, P < 0.001), but not macular carotenoids (stdβ = -0.04, P = 0.70). Neither MPOD nor skin carotenoids were associated with age, sex, or race (all P > 0.10). MPOD was positively associated with energy-adjusted reported lutein + zeaxanthin intake (stdβ = 0.27, P = 0.01). Skin carotenoids were positively associated with energy-adjusted reported carotenoid intake (stdβ = 0.26, P = 0.01).
CONCLUSIONS
The mean MPOD values in children were higher than what has been reported in adult populations. Previous studies in adult samples report an average MPOD of 0.21. Although macular and skin carotenoids were not related, they were associated with dietary carotenoids relevant to the respective tissues; however, skin carotenoids may be more susceptible negative influence from higher weight status.
Topics: Adult; Humans; Child; Macular Pigment; Lutein; Zeaxanthins; Macula Lutea; Retina
PubMed: 37315793
DOI: 10.1016/j.tjnut.2023.06.006 -
Nutrients Oct 2023We examined the associations of perinatal plasma carotenoids and E vitamers concentrations with glycemia, insulin resistance, and gestational and type 2 diabetes...
We examined the associations of perinatal plasma carotenoids and E vitamers concentrations with glycemia, insulin resistance, and gestational and type 2 diabetes mellitus during pregnancy and post-pregnancy in GUSTO women. Plasma carotenoid and E vitamer concentrations were measured at delivery, and principal component analysis was used to derive the patterns of their concentrations. Fasting and 2 h glucose levels and fasting insulin were measured at 26-28 weeks gestation and 4-6 years post-pregnancy, with the derivation of homeostatic model assessment for insulin resistance (HOMA-IR). In 678 women, two carotenoid patterns (CP1: α- and β-carotene and lutein; CP2: zeaxanthin, lycopene, and β-cryptoxanthin) and one E vitamer pattern (VE: γ-, δ-, and α-tocopherols) were derived. A higher CP1 score (1-SD) was associated with lower gestational fasting glucose (β (95%CI): -0.06 (-0.10, -0.02) mmol/L) and lower gestational (-0.17 (-0.82, 0.01) mmol/L, = 0.06) and post-pregnancy HOMA-IR (-0.11 (-0.15, -0.08) mmol/L). A higher VE score (1 SD) was associated with higher gestational and post-pregnancy fasting and 2 h glucose (gestational: 0.05 (0.01, 0.08) and 0.08 (0.01, 0.16); post-pregnancy: 0.19 (0.07, 0.31) and 0.24 (0.06, 0.42) mmol/L). Higher α- and β-carotene and lutein may be beneficial for gestational fasting glycemia, but higher vitamin E may increase gestational and post-pregnancy glycemia, although these findings require confirmation in cohorts with prospective longitudinal measurements of these vitamins.
Topics: Pregnancy; Humans; Female; Carotenoids; beta Carotene; Vitamin E; Lutein; Insulin Resistance; Diabetes Mellitus, Type 2; Prospective Studies; Glucose
PubMed: 37892496
DOI: 10.3390/nu15204421 -
Nutrients Mar 2022Vitamin A is vital to maternal-fetal health and pregnancy outcomes. However, little is known about pregnancy associated changes in maternal vitamin A homeostasis and...
Vitamin A is vital to maternal-fetal health and pregnancy outcomes. However, little is known about pregnancy associated changes in maternal vitamin A homeostasis and concentrations of circulating retinol metabolites. The goal of this study was to characterize retinoid concentrations in healthy women ( = 23) during two stages of pregnancy (25-28 weeks gestation and 28-32 weeks gestation) as compared to ≥3 months postpartum. It was hypothesized that plasma retinol, retinol binding protein 4 (RBP4), transthyretin and albumin concentrations would decline during pregnancy and return to baseline by 3 months postpartum. At 25-28 weeks gestation, plasma retinol (-27%), 4-oxo-13--retinoic acid (-34%), and albumin (-22%) concentrations were significantly lower, and -retinoic acid (+48%) concentrations were significantly higher compared to ≥3 months postpartum in healthy women. In addition, at 28-32 weeks gestation, plasma retinol (-41%), retinol binding protein 4 (RBP4; -17%), transthyretin (TTR; -21%), albumin (-26%), 13--retinoic acid (-23%) and 4-oxo-13--retinoic acid (-48%) concentrations were significantly lower, whereas plasma -retinoic acid concentrations (+30%) were significantly higher than ≥3 months postpartum. Collectively, the data demonstrates that in healthy pregnancies, retinol plasma concentrations are lower, but -retinoic acid concentrations are higher than postpartum.
Topics: Female; Humans; Prealbumin; Pregnancy; Pregnant Women; Retinoids; Retinol-Binding Proteins, Plasma; Tretinoin; Vitamin A
PubMed: 35405978
DOI: 10.3390/nu14071365 -
Analytical Chemistry Mar 2022The ability to monitor the uptake and distribution of food nutrients in cell culture models is key to understanding the efficacy of these nutraceuticals to treat and...
The ability to monitor the uptake and distribution of food nutrients in cell culture models is key to understanding the efficacy of these nutraceuticals to treat and prevent disease. Lycopene is a carotenoid found in chloroplasts and chromoplasts of tomatoes, providing the familiar red color, and a bioactive that inhibits prostate carcinogenesis. We employed live-cell Raman microscopy to visualize lycopene delivery from tween 80 micelles into PC-3 prostate cancer cells. The tween 80 micelle provides a mimic of natural lipoprotein complexes that deliver lycopene , overcomes the low aqueous solubility of lycopene and challenges replicating physiological uptake to cells, and provides a stable signal to assess cellular uptake of the nutraceutical formulation. The Raman images indicate subcellular localization of the lycopene within the cells. The lycopene Raman signal is resonantly enhanced at an excitation wavelength of 532 nm, providing a convenient, sensitive, and label-free technique to detect and quantify lycopene uptake in living cells. Analysis of the acquired Raman spectra in the maps determines the concentration of lycopene at each point in the cell. In addition to the expected lycopene Raman signal, Raman scattering from the tween 80 vehicle is also mapped in the cells. The Raman data correlates with scattering features observed in darkfield microscopy images of the cells, which display the cell membrane and other features for reference. Overall, the Raman maps indicate lycopene likely accumulates in lipid membranes of cytoplasmic organelles.
Topics: Carotenoids; Diagnostic Imaging; Humans; Lycopene; Male; Prostate; Prostatic Neoplasms
PubMed: 35289593
DOI: 10.1021/acs.analchem.1c05442 -
Journal of Lipid Research 2021Vitamin A aldehyde covalently bound to opsin protein is embedded in a phospholipid-rich membrane that supports photon absorption and phototransduction in photoreceptor... (Review)
Review
Vitamin A aldehyde covalently bound to opsin protein is embedded in a phospholipid-rich membrane that supports photon absorption and phototransduction in photoreceptor cell outer segments. Following absorption of a photon, the 11-cis-retinal chromophore of visual pigment in photoreceptor cells isomerizes to all-trans-retinal. To maintain photosensitivity 11-cis-retinal must be replaced. At the same time, however, all-trans-retinal has to be handled so as to prevent nonspecific aldehyde activity. Some molecules of retinaldehyde upon release from opsin are efficiently reduced to retinol. Other molecules are released into the lipid phase of the disc membrane where they form a conjugate [N-retinylidene-PE (NRPE)] through a Schiff base linkage with PE. The reversible formation of NRPE serves as a transient sink for retinaldehyde that is intended to return retinaldehyde to the visual cycle. However, if instead of hydrolyzing to PE and retinaldehyde, NRPE reacts with a second molecule of retinaldehyde, a synthetic pathway is initiated that leads to the formation of multiple species of unwanted bisretinoid fluorophores. We report on recently identified members of the bisretinoid family, some of which differ with respect to the acyl chains associated with the glycerol backbone. We discuss processing of the lipid moieties of these fluorophores in lysosomes of retinal pigment epithelial cells, their fluorescence characters, and new findings related to light- and iron-associated oxidation of bisretinoids.
Topics: Retinaldehyde
PubMed: 32371567
DOI: 10.1194/jlr.TR120000742 -
Asian Pacific Journal of Cancer... Mar 2022To examine the association between dietary intake of Trans-Lycopene and β-Cryptoxanthin and stomach cancer in Vietnamese men.
OBJECTIVE
To examine the association between dietary intake of Trans-Lycopene and β-Cryptoxanthin and stomach cancer in Vietnamese men.
METHODS
A case-control study including 80 male incident stomach cancer cases and 146 male controls was performed in a general hospital in Viet Nam. A validated semi-quantitative food frequency (SQFFQ) and demographic lifestyle questionnaire were designed, and venous blood samples were collected to determine H. pylori status by IgG ELISA. Nutrient intake was converted using the data of SQFFQ and the Nutritive Composition Table of Vietnamese Foods, updated in 2019. The respective associations between Trans-Lycopene and β-Cryptoxanthin intake and stomach cancer were examined using unconditional logistic regression analysis with adjustments for possible cofactors.
RESULTS
Both Trans-Lycopene and β-Cryptoxanthin intake and stomach cancer showed a significantly inverse association, tertile-3 versus tertile-1, (OR = 0.15, 95%CI: 0.06-0.35, p trend = 0.00) and (OR = 0.34, 95%CI: 0.14-0.79, p trend = 0.02, respectively). For Trans-Lycopene intake stratifying by H. pylori status remained the benefit effect against stomach cancer among H. pylori-negative participants (OR = 0.15, 95%CI: 0.03-0.69, p trend = 0.02) and H. pylori-positive participants (OR = 0.13, 95%CI: 0.04-0.42, p trend = 0.00).
CONCLUSIONS
Both Trans-Lycopene and β-Cryptoxanthin intake showed a strong protective effect against stomach cancer. The findings suggest that these two types of fat-soluble micronutrients would be considered as an anti-cancer therapy for both primary and secondary prevention.
Topics: Asian People; Beta-Cryptoxanthin; Carotenoids; Case-Control Studies; Humans; Lycopene; Male; Risk Factors; Stomach Neoplasms; Vietnam
PubMed: 35345357
DOI: 10.31557/APJCP.2022.23.3.861