Direct Extraction of Lipids, ß-Carotene, and Polyphenolic Compounds from Wet Microalga Dunaliella salina by Liquefied Dimethyl Ether.

Extraction of lipids and high-value products from highly wet microalgae requires significant energy for the drying pretreatment. In this study, we examined the direct extraction of lipids, ß-carotene, and polyphenolic compounds from wet Dunaliella salina using liquefied dimethyl ether (DME), which is effective in lipid extraction for biofuel production. The amount of DME-extracted ß-carotene was 7.0 mg/g, which was higher than that obtained from the chloroform-methanol extraction. Moreover, the total phenolic content extracted with DME and its antioxidant capacity were slightly higher than those extracted with chloroform-methanol. DME removed almost all the water and extracted 29.2 wt% of total lipids and 9.7 wt% of fatty acids. More lipids were extracted from wet samples by liquefied DME than by chloroform-methanol extraction. The C/N ratio of lipids extracted with DME was 112.0, higher than that of chloroform-methanol. The high C/N ratio suggests that nitrogen-containing phosphatidylcholines may be less easily extracted by liquefied DME and may be highly selective. However, the ratio of saturated fatty acids was 34.8%, lower than that of chloroform-methanol. Na+ and Mg2+ in the culture medium were not extracted using DME. Thus, using the extract with DME has both advantages and disadvantages compared to using the extract with chloroform-methanol; however, it has satisfactory extraction properties. DME is expected to be an environment-friendly alternative solvent because it does not require drying, which is necessary for conventional extraction solvents.

Astaxanthin Is a Novel Candidate for Glioblastoma Treatment? A Review.

Glioblastoma (GBM) is a malignant primary brain tumor with a poor prognosis and high recurrence rates. At present, the current treatments available for GBM patients can only prolong their overall survival and cannot provide a complete cure. Discovering an effective therapy against the disease is a challenge due to its recurrence and resistance to common available treatments for GBM. Several natural products have been documented to possess the potential to function as anticancer agents through diverse mechanisms. Astaxanthin (AXT) is an orange-red pigment that is a natural lipophilic and xanthophyll carotenoid derived mostly from microalgae. Numerous studies have examined that AXT impacts GBM cells in laboratory settings and animal models. This review aims to provide the latest information about the potential of astaxanthin as a novel therapeutic option for GBM. AXT has been targeted more on reactive oxygen species (ROS), and suppressed tumor growth in vitro and in vivo conditions. The available data suggests that AXT might serve as a key component in the development of innovative cancer therapies, especially for glioblastoma.

Sphingomonas rustica sp. nov. and Sphingomonas agrestis sp. nov., novel carotenoid-producing bacterial species isolated from farm soil.

Two yellow-pigmented novel strains, designated HF-S3T and HF-S4T, were isolated from farm soil in Paju, Republic of Korea. Cells of the two strains are characteristically Gram-stain-negative, facultatively anaerobic, catalase- and oxidase-positive, non-motile and rod-shaped. Strain HF-S3T grew at 10-37 °C, while HF-S4T grew at 15-35 °C. Both strains grew at pH 5.0-12.0 and in NaCl concentrations (w/v) of 0-2.0%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that HF-S3T and HF-S4T belong to the genus Sphingomonas, with HF-S3T exhibiting 97.7, 97.6 and 97.4% similarity to Sphingomonas cannabina DM2-R-LB4T, Sphingomonas leidyi DSM 4733T and Sphingomonas canadensis FWC47T, respectively. Strain HF-S4T displayed 97.9, 97.7 and 97.6% similarity to Sphingomonas psychrotolerans Cra20T, Sphingomonas gei ZFGT-11T and Sphingomonas naasensis KIS18-15T, respectively. The DNA G+C contents of HF-S3T and HF-S4T were 67.0 and 66.5 mol%, respectively. The digital DNA-DNA hybridization and average nucleotide identity values among the novel and related type strains were 20.2-28.2% and 75.9-84.3%, respectively. They all contained C14:0 2-OH and C16:0, summed feature 8 (C18:1 ω6c and/or C18:1 ω7c) as the major fatty acids and ubiquinone-10 as the predominant respiratory quinone. Strains HF-S3T and HF-S4T were found to produce carotenoid-type pigments. Based on polyphasic taxonomic analysis, the new isolates ostensibly represent two novel species of the genus Sphingomonas, with the proposed names Sphingomonas rustica sp. nov. and Sphingomonas agrestis sp. nov. for strains HF-S3T and HF-S4T, respectively. The S. rustica and S. agrestis type strains are HF-S3T (=KACC 23554T =TBRC 18352T) and HF-S4T (=KACC 23386T =TBRC 17899T), respectively.

Bcwf regulates the white petal color in pak choi [Brassica campestris (syn. Brassica rapa) ssp. chinensis].

Flower color is important in determining the ornamental value of Brassica species. However, our knowledge about the regulation of flower color in pak choi [Brassica campestris (syn. Brassica rapa) ssp. chinensis] is limited. In this study, we investigated the molecular mechanism underlying white flower traits in pak choi by analyzing a genetic population with white and yellow flowers. Our genetic analysis revealed that the white trait is controlled by a single recessive gene called Bcwf. Through BSA-Seq and fine mapping, we identified a candidate gene, BraC02g039450.1, which is similar to Arabidopsis AtPES2 involved in carotenoid ester synthesis. Sequence analysis showed some mutations in the promoter region of Bcwf in white flowers. Tobacco transient assay confirmed that these mutations reduce the promoter's activity, leading to downregulation of Bcwf expression in white flowers. Furthermore, the silencing of Bcwf in pak choi resulted in lighter petal color and reduced carotenoid content. These findings provide new insights into the molecular regulation of white flower traits in pak choi and highlight the importance of Bcwf in petal coloring and carotenoid accumulation.

First Vesicular Self-assembly of an Apocarotenoid Bixin in Aqueous Liquids and its Antibacterial Activity.

Bixin1 is the major constituent of the reddish carotenoids present in the seed-coat of Bixa orellana.  The use of the extract of the seed-coat of Bixa orellana in food, cosmetics and garments is well known. The nano-sized long 24C chain molecule has nine conjugated double bonds having extended conjugation with the '-COOH' and '-COOMe' groups present at the two ends of the molecule.  Herein, we report the first self-assembly of bixin in several aqueous liquids. The molecule undergoes spontaneous self-assembly in several liquids yielding vesicular self-assembly.  Characterizations of the self-assemblies of bixinwere carried out by various microscopic techniques, X-ray diffraction and FTIR studies. The critical vesicular concentrations (CVCs) of the compound carried out in DMSO-water in three different solvent ratios as 2: 1 (v/v), 1: 1 (v/v) and 1: 4 (v/v) were determined to be 100 mM, 90 mM and 60 mM respectively indicating lower CVC values at higher proportion of water. Utilization of the vesicular self-assemblies of bixin have been demonstrated in the entrapment and release of fluorophores including the anticancer drugs doxorubicin and curcumin.  Self-assembled bixin and curcumin loaded self-assembled bixin showed significant antibacterial activity with both Gram positive as well as Gram negative bacteria.

Influence of exogenous 24-epibrassinolide on improving carotenoid content, antioxidant capacity and gene expression in germinated maize seeds.

BACKGROUND: Carotenoids have various physiological functions, such as immune regulation and cancer prevention. Germination could further improve the content of carotenoids in maize seeds. In this study, yellow maize seeds (Suyu 29) were soaked and germinated with different concentrations of 24-epibrassinolide. The changes of germination percentage, sprout length, bioactive components, antioxidant capacity and carotenoid content of the maize seeds were analyzed. Additionally, the relative expression of key genes in the carotenoid synthesis pathway was investigated. RESULTS: The results showed that the sprout length, germination percentage, soluble protein, free amino acids, proline, endogenous abscisic acid, vitamin C, total phenolics and carotenoids displayed a significant increasing trend compared with the control group (P < 0.05). The activity of superoxide dismutase and peroxidase increased by 55.1% and 58.5% versus the control group, and the antioxidant capacity of 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and ferric reducing antioxidant power was 19.8%, 13.4% and 44.1% higher than that of the control group (P < 0.05). Compared with the control group, the expression of genes was significantly up-regulated (P < 0.05). Under the treatment of 0.1 mg L-1 of 24-epibrassinolide, carotenoid content reached the highest value. The carotenoids showed a positive correspondence with antioxidant enzyme activity, antioxidant capacity and total phenolics content (P < 0.05). CONCLUSION: This study showed that 0.1 mg L-1 of exogenous 24-epibrassinolide promoted the accumulation of carotenoids and improved the antioxidant capacity and the quality of germinated maize seeds. It could provide a method for the development of germinated maize products enriched in carotenoids. © 2024 Society of Chemical Industry.

DcMYB62, a transcription factor from carrot, enhanced cadmium tolerance of Arabidopsis by inducing the accumulation of carotenoids and hydrogen sulfide.

Cadmium (Cd) is a significant heavy metal contaminant within the environment, carrying a notable level of toxicity that presents a substantial hazard to both plant and human. Carrot (Daucus carota), a significant root vegetable crop globally, have evolved multiple transcriptional regulatory mechanisms to cope with Cd stress, with a crucial involvement of the myeloblastosis (MYB) transcription factor. In this study, the DcMYB62 gene encoding 288 amino acids, localized in the nucleus and demonstrated transcription activation property, was isolated from carrot (cv. 'Kuroda'). There was a positive relationship observed between the levels of DcMYB62 expression and the accumulation patterns of carotenoids in two distinct carrot cultivars. Further investigation revealed that the expression of DcMYB62 improved Cd tolerance of Arabidopsis by increasing seed germination rate, root length, and overall survival rate. The levels of carotenoids in DcMYB62 transgenic Arabidopsis surpassed those in wild type, accompanied by elevated expression levels of 15-cis-phytoene desaturase, zeta-carotene desaturase, and carotenoid isomerase. Meanwhile, the heterologous expression of DcMYB62 promoted the biosynthesis of abscisic acid (ABA) and hydrogen sulfide (H2S), which in turn suppressed the formation of hydrogen peroxide and superoxide anion, while also stimulating stomatal closure. Furthermore, the heterologous expression of DcMYB62 increased the transcription of genes associated with heavy metal resistance in Arabidopsis, notably nicotianamine synthase. Overall, this study contributes to understanding how DcMYB62 promote Cd stress resistance of plants by regulating the biosynthesis pathways of carotenoids, ABA, and H2S, which offers valuable insights into the regulatory mechanism connecting DcMYBs with Cd stress response of carrot.

The Antitumour Mechanisms of Carotenoids: A Comprehensive Review.

Carotenoids, known for their antioxidant properties, have garnered significant attention for their potential antitumour activities. This comprehensive review aims to elucidate the diverse mechanisms by which carotenoids exert antitumour effects, focusing on both well-established and novel findings. We explore their role in inducing apoptosis, inhibiting cell cycle progression and preventing metastasis by affecting oncogenic and tumour suppressor proteins. The review also explores the pro-oxidant function of carotenoids within cancer cells. In fact, although their overall contribution to cellular antioxidant defences is well known and significant, some carotenoids can exhibit pro-oxidant effects under certain conditions and are able to elevate reactive oxygen species (ROS) levels in tumoural cells, triggering mitochondrial pathways that would lead to cell death. The final balance between their antioxidant and pro-oxidant activities depends on several factors, including the specific carotenoid, its concentration and the redox environment of the cell. Clinical trials are discussed, highlighting the conflicting results of carotenoids in cancer treatment and the importance of personalized approaches. Emerging research on rare carotenoids like bacterioruberin showcases their superior antioxidant capacity and selective cytotoxicity against aggressive cancer subtypes, such as triple-negative breast cancer. Future directions include innovative delivery systems, novel combinations and personalized treatments, aiming to enhance the therapeutic potential of carotenoids. This review highlights the promising yet complex landscape of carotenoid-based cancer therapies, calling for continued research and clinical exploration.

A novel C2H2-type zinc-finger transcription factor, CitZAT4, regulates ethylene-induced orange coloration in Satsuma mandarin flavedo (Citrus unshiu Marc.).

Ethylene treatment promotes orange coloration in the flavedo of Satsuma mandarin (Citrus unshiu Marc.) fruit, but the corresponding regulatory mechanism is still largely unknown. In this study, we identified a C2H2-type zinc-finger transcription factor, CitZAT4, the expression of which was markedly induced by ethylene. CitZAT4 directly binds to the CitPSY promoter and activates its expression, thereby promoting carotenoid biosynthesis. Transient expression in Satsuma mandarin fruit and stable transformation of citrus calli showed that overexpressing of CitZAT4 inhibited CitLCYE expression, thus inhibiting α-branch yellow carotenoid (lutein) biosynthesis. CitZAT4 overexpression also enhanced the transcript levels of CitLCYB, CitHYD, and CitNCED2, promoting ß-branch orange carotenoid accumulation. Molecular biochemical assays, including yeast one-hybrid (Y1H), electrophoretic mobility shift (EMSA), chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR), and luciferase (LUC) assays, demonstrated that CitZAT4 directly binds to the promoters of its target genes and regulates their expression. An ethylene response factor, CitERF061, which is induced by ethylene signaling, was found to directly bound to the CitZAT4 promoter and induced its expression, thus positively regulating CitZAT4-mediated orange coloration in citrus fruit. Together, our findings reveal that a CitZAT4-mediated transcriptional cascade is driven by ethylene via CitERF061, linking ethylene signaling to carotenoid metabolism in promoting orange coloration in the flavedo of Satsuma mandarin fruit. The molecular regulatory mechanism revealed here represents a significant step toward developing strategies for improving the quality and economic efficiency of citrus crops.

Study on the Metabolic Basis of the Color Formation of Two Color-Presenting Types of Jujube Fruits.

Jujube is a plant of the genus Ziziphus in the family Rhamnaceae; its fruit has high nutritional value, and it is rich in polyphenols, flavonoids, and other secondary metabolites. The color of its peel is an important indicator for evaluating the appearance of the fruit. However, the mechanism of the difference in color presentation between the seedling offspring of the 'Red Fruit' (TLHH) and the 'Green Fruit' (TLHL) of the fresh jujube cultivar 'Tailihong' is not clear. Therefore, this study used targeted metabolomics techniques to accurately and quantitatively analyze the metabolic pathways of carotenoid and anthocyanin metabolites during the ripening process of two color-presenting types of jujube fruits. Through the analysis of the dynamic changes in the pigment content of the jujube peel, it was found that 30 DAP (days after pollination), 80 DAP, and 110 DAP were the key periods for the development of the color of the peel of 'TLHL' and 'TLHH' jujube and that the substances responsible for the main differences were chlorophyll, carotenoids, and anthocyanins. Furthermore, we used an LC-MS/MS metabolic analysis to compare the differences in the carotenoids and anthocyanin metabolites between the two color-presenting types of jujube peels at the key periods of 30 DAP, 80 DAP, and 110 DAP. We detected 32 carotene metabolites and 75 anthocyanin metabolites, respectively, among which lutein had the highest content of carotenoids; it reached the maximum value (93.05 µg/g) and was higher than that of 'TLHH' (74.14 µg/g) at 30 DAP of 'TLHL'. Both showed a decreasing trend with fruit ripening. The anthocyanin with the highest content was cyanidin-3-O-(tartaryl)rhamnoside-5-O-glucoside, which reached the maximum value (258.32 µg/g) at 30 DAP of 'TLHH' and was 51.6 times that of 'TLHL'; similarly, both showed a decreasing trend with fruit ripening. These results elucidate the main metabolites of carotenoids and anthocyanins in the two types of jujube peel and their accumulation characteristics, suggesting that the key metabolites of the difference in color between 'TLHL' and 'TLHH' jujube fruits were lutein and cyanidin-3-O-(tartaryl)rhamnoside-5-O-glucoside, increasing the understanding of the color mechanism of jujube peel and providing a reference for targeted genetic breeding of jujube peel color.

An Overview on the Effects of Some Carotenoids on Health: Lutein and Zeaxanthin.

PURPOSE OF REVIEW: In this review, the chemical properties, nutritional sources, absorption mechanisms, metabolism, biosynthesis and promising health-related benefits of lutein and zeaxanthin were emphasized and some recommendations for the future studies are suggested. RECENT FINDINGS: Lutein and zeaxanthin are phytochemical compounds in the carotenoid group and are synthesised only by plants. All mammals get lutein and zeaxanthin into their bodies by consuming plant-based foods. Especially leafy green vegetables, broccoli, pumpkin, cabbage, spinach and egg yolk are rich in lutein and zeaxanthin. Lutein and zeaxanthin have potential health effects by preventing free radical formation, exhibiting protective properties against oxidative damage and reducing oxidative stress. These compounds have neuroprotective, cardioprotective, ophthalmological, antioxidant, anti-inflammatory, anti-cancer, anti-osteoporosis, anti-diabetic, anti-obesity, and antimicrobial effects. The preventive properties of lutein and zeaxanthin against numerous diseases have attracted attention recently. Further clinical trials with large samples are needed to make generalisations in the prevention and treatment of diseases and to determine the appropriate doses and forms of lutein and zeaxanthin.

Parent-child skin carotenoid level and vegetable intake relationships in users of children's cafeterias in Japan.

Introduction: Studies on the relationship between parental and child dietary intakes are limited in Asian populations. Here, we examined parent-child relationships in skin carotenoid levels and vegetable intake in a Japanese community. Methods: The study participants were 58 children aged 6-15 years and 39 of their guardians (parents) using children's cafeterias. Skin carotenoid levels were measured using the Veggie Meter®, and the number of vegetable dishes (equivalent to a serving of 70 g) was evaluated using a self-administered questionnaire. Results: The mean (standard deviation; SD) skin carotenoid levels were 366.8 (74.0) in children and 315.0 (101.4) in parents. The partial correlation coefficient between parents' and children's skin carotenoid levels, adjusting for cafeteria, sex, parental dietary supplement use, and household financial status, was 0.38 (P = 0.02); after adjustment for smoking status and BMI, the positive correlation was attenuated (r = 0.25, P = 0.14). A positive correlation was observed between parents' and children's vegetable dish intake (r = 0.30, P = 0.02). Conclusion: This cross-sectional study identified a positive correlation between parent-child intake of vegetable dishes, accounting for potential confounders. However, the positive correlation observed between parent-child skin carotenoid levels may have been attenuated by internal factors such as smoking and obesity.

Carotenoid-Producing Paracoccus aurantius sp. nov., Isolated from the West Coast of Dokdo Island, Republic of Korea.

In this study, a novel species within the genus Paracoccus was isolated from the coastal soil of Dokdo (Seodo) Island and investigated. We elucidated the novel species, designated MBLB3053T, through genomic analysis of novel functional microbial resources. Cells were gram-negative, non-motile, and coccoid, and the colony was light orange in color. Phylogenetic analysis based on the 16S rRNA gene showed that strain MBLB3053T was related to the genus Paracoccus, with 98.5% similarity to Paracoccus aestuariivivens. Comparative genome analysis also revealed the strain to be a novel species of the genus Paracoccus by average nucleotide identity and in silico DNA-DNA hybridization values. Through secondary metabolite analysis, terpene biosynthetic gene clusters associated with carotenoid biosynthesis were found in strain MBLB3053T. Using high-performance liquid chromatography, strain MBLB3053T was confirmed to produce carotenoids, including all-trans-astaxanthin, by comparison to the standard compound. Notably, the isolate was also confirmed to produce carotenoids that other closely related species did not produce. Based on this comprehensive polyphasic taxonomy, strain MBLB3053T represents a novel species within the genus Paracoccus, for which the name Paracoccus aurantius sp. nov is proposed. The type strain was MBL3053T (=KCTC 8269T =JCM 36634T). These findings support the research and resource value of this novel species, which was isolated from the Dokdo environmental microbiome.

Extra-virgin olive oil enriched with lycopene: From industrial tomato by-products to consumer.

Lycopene is usually extracted from the by-product of the tomato industry using organic solvents (OS) in combination with a physical technique. An emerging physical technique is high-pressure processing (HPP). This study aims to find a method by applying a green solvent (edible vegetable oils) in an HPP-assisted solid-liquid extraction. Three dosages of tomato by-product (10%, 20%, and 40%, w/v) were tested using OS, sunflower oil (RSO), and extra-virgin olive oil (EVOO). Lycopene recovery increased with the ratio of by-product to oil, particularly when using EVOO. In another stage of the study, consumers evaluated EVOO that contained two doses of tomato by-product (10% and 20%, w/v). Consumers preferred the EVOO from 10% tomato by-product ratio over that with 20%. Additionally, 83.8% of consumers stated that enriched oil could be deemed beneficial for health. The proposed method considers the fundamental principles of the circular economy and practical industrial scenario to recover lycopene from tomato by-product.

Evaluation of the Impact of the Ripening Stage on the Composition and Antioxidant Properties of Fruits from Organically Grown Tomato (Solanum lycopersicum L.) Spanish Varieties.

Tomato (Solanum lycopersicum L.) is a widely cultivated horticultural crop. It belongs to the Solanaceae family and is known for its high concentration of essential nutrients, including vitamins, minerals, and bioactive compounds with antioxidant properties. The Mediterranean countries, including Italy, Spain, and Greece, have a diverse range of tomato landraces. Assessing the nutritional and bioactive composition of different tomato varieties and their ripening stages is crucial to determine their suitability for the market. Therefore, the aim of this study was to investigate the effect of ripening on nutritional composition (including carotenoids and polyphenols content) and antioxidant activities of fruits of three specific tomato varieties grown in Spain: Josefina and Karelya, which are cherry-like tomatoes, and Muchamiel, a type of salad tomato. In addition to evaluating their characteristics and composition (including carotenoids and polyphenol content), the antioxidant activities of these varieties at three different ripening stages were quantified. As expected, the results reveal that, as the tomatoes matured, their antioxidant capacity increased along with higher levels of carotenoids and polyphenols. Interestingly, cherry-like tomatoes showed a higher antioxidant activity than the salad tomatoes. This investigation emphasizes the role of fruit ripening in increasing carotenoid levels, which contribute to the antioxidant activity of three tomato varieties.

Associations of multiple carotenoid co-exposure with all-cause and cause-specific mortality in US adults: a prospective cohort study.

Background: Epidemiological evidence regarding circulating carotenoids and mortality risk remains conflicting, and most studies focus on the impact of individual carotenoids. This study aimed to elucidate the effects of co-exposure to multiple serum carotenoids on mortality risk. Methods: We enrolled 22,472 participants aged ≥20 from the National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and NHANES 2003-2006. Baseline serum levels of five major carotenoids (α-carotene, ß-carotene, lycopene, ß-cryptoxanthin, and lutein/zeaxanthin) were measured, and individuals were followed up until December 31, 2019. Carotenoid co-exposure patterns were identified using the K-means method. Cox proportional hazard models were used to investigate the associations between carotenoid exposure and mortality risk. Results: During a median follow-up of 16.7 years, 7,901 deaths occurred. K-means clustered participants into low-level, low-lycopene, high-lycopene, and high-level exposure groups. In the fully adjusted model, low-lycopene, high-lycopene, and high-level exposure groups had significantly lower all-cause mortality risks compared to the low-level exposure group, with hazard ratios (HRs) and 95% confidence intervals (CIs) of 0.79 (0.72, 0.87), 0.75 (0.67, 0.84), and 0.67 (0.61, 0.74), respectively. For cardiovascular disease mortality, the high-lycopene exposure group had a 27% reduced risk (HR: 0.73, 95% CI: 0.61-0.86), and the high-level exposure group had a 21% reduced risk (HR: 0.79, 95% CI: 0.67-0.93). For cancer mortality, the high-lycopene and high-level exposure groups had 30% and 35% lower risks, with HRs (95% CIs) of 0.70 (0.57, 0.86) and 0.65 (0.54, 0.79), respectively. Conclusion: This study revealed that co-exposure to multiple serum carotenoids was associated with reduced mortality risk, highlighting the potential health benefits of increased carotenoid intake. Further investigation is warranted to elucidate the underlying mechanisms of interactions among different carotenoids.

Metabolic Engineering of Candida tropicalis for the De Novo Synthesis of ß-Ionone.

ß-ionone, a norisoprenoid, is a natural aromatic compound derived from plants, which displays various biological activities including anticancer, antioxidant and deworming properties. Due to its large biomass and strong environmental tolerance, the nonconventional oleaginous yeast Candida tropicalis was selected to efficiently synthesize ß-ionone. We initially investigated the capacity of the cytoplasm and subcellular compartments to synthesize ß-ionone independently. Subsequently, through adaptive screening of enzymes, functional identification of subcellular localization signal peptides and subcellular compartment combination strategies, a titer of 152.4 mg/L of ß-ionone was achieved. Finally, directed evolution of rate-limiting enzyme and overexpression of key enzymes were performed to enhance ß-ionone production. The resulting titer was 400.5 mg/L in shake flasks and 730 mg/L in a bioreactor. This study demonstrates the first de novo synthesis of ß-ionone in C. tropicalis, providing a novel cellular chassis for terpenoid fragrances with considerable industrial potential.

DWARF27 and CAROTENOID CLEAVAGE DIOXYGENASE 7 genes regulate release, germination and growth of gemma in Marchantia polymorpha.

Strigolactones (SLs), a class of carotenoid-derived hormones, play a crucial role in flowering plants by regulating underground communication with symbiotic arbuscular mycorrhizal fungi (AM) and controlling shoot and root architecture. While the functions of core SL genes have been characterized in many plants, their roles in non-tracheophyte plants like liverworts require further investigation. In this study, we employed the model liverwort species Marchantia polymorpha, which lacks detectable SL production and orthologs of key SL biosynthetic genes, including CAROTENOID CLEAVAGE DIOXYGENASE 8 (CCD8) and MORE AXILLARY GROWTH 1 (MAX1). However, it retains some SL pathway components, including DWARF27 (D27) and CCD7. To help elucidate the function of these remaining components in M. polymorpha, knockout mutants were generated for MpD27-1, MpD27-2 and MpCCD7. Phenotypic comparisons of these mutants with the wild-type control revealed a novel role for these genes in regulating the release of gemmae from the gemma cup and the germination and growth of gemmae in the dark. Mpd27-1, Mpd27-2, and Mpccd7 mutants showed lower transcript abundance of genes involved in photosynthesis, such as EARLY LIGHT INDUCED (ELI), and stress responses such as LATE EMBRYOGENESIS ABUNDANT (LEA) but exhibited higher transcript levels of ETHYLENE RESPONSE FACTORS (ERFs) and SL and carotenoid related genes, such as TERPENE SYNTHASE (TS), CCD7 and LECITHIN-RETINAL ACYL TRANSFERASE (LRAT). Furthermore, the mutants of M. polymorpha in the SL pathway exhibited increased contents of carotenoid. This unveils a previously unrecognized role for MpD27-1, MpD27-2 and MpCCD7 in controlling release, germination, and growth of gemmae in response to varying light conditions. These discoveries enhance our comprehension of the regulatory functions of SL biosynthesis genes in non-flowering plants.

Gum tragacanth, a novel edible coating, maintains biochemical quality, antioxidant capacity, and storage life in bell pepper fruits.

Bell pepper fruits (Capsicum annuum L.) are prone to both physiological and pathological deterioration following harvest, primarily due to their high metabolic activity and water content. The storage of bell peppers presents several challenges, including weight loss, softening, alterations in fruit metabolites and color, increased decay, and a decline in marketability. The application of edible coatings (ECs) is one of the environmentally friendly technologies that improves many post-harvest quantitative and qualitative characteristics of products. This research investigated the impact of different levels of gum tragacanth (GT) coating (0, 0.25, 0.5, 1, and 2%) on the physiological and biochemical traits of stored bell pepper fruits (BPFs) (8 ± 1°C, 90-95% RH) for 28 days. The results showed the positive effect of coating treatments with higher concentrations of GT, up to 1%. Increasing the concentration of GT to 2% decreased the marketability and quality characteristics of fruits compared to 1% GT. After storage, the physiological weight loss of the fruits treated with 1% GT (10.46%) was lower than that of the uncoated fruits (18.92%). Furthermore, the coated fruits (1% GT) had more firmness, total phenol content, ascorbic acid, and titratable acidity content than uncoated fruits during storage. At the end of storage, the coated BPFs with 1% GT showed higher SOD (97.02 U g-1), CAT (24.38 U g-1) and POD (0.11 U g-1) activities and antioxidant capacity (81.74%) as compared to other treatments. Total soluble solids, total carbohydrates, total carotenoids, pH, malondialdehyde, and electrolyte leakage content increased in coated fruit during storage but were significantly lower than in uncoated fruits. Moreover, the samples coated with GT (1%) maintained good marketability (about 75%), while the marketability of the control (about 40%) was unacceptable. The study shows that GT (1%) coating can be a promising novel treatment option for increasing the storage quality of BPFs.

Antioxidant Activity of Aqueous Extracts Obtained from By-Products of Grape, Olive, Tomato, Lemon, Red Pepper and Pomegranate.

The aim of this work was to study the antioxidant potential of aqueous extracts obtained from different by-products. The effectiveness of these extracts was compared with that of rosemary extract. Total phenol carotenoid and vitamin C contents, as well as in vitro antioxidant activity, were assessed. Phenol content was positively correlated with in vitro antioxidant activity in extracts, while carotenoids showed a less clear relationship. Vitamin C was associated with antioxidant activity in lemon and pepper pomace extracts. Extracts from olive, grape, and lemon by-products displayed the highest antioxidant activity (radical scavenging activity), this being similar to the activity of rosemary extracts. Moreover, the phenolic profile of the extracts was analyzed, revealing diverse phenolic compounds. Rosemary extracts contained the highest variety and quantity of phenolic compounds, while olive pomace extracts were rich in hydroxytyrosol and 4-hydroxybenzoic acid. Lemon and pepper extracts contained high amounts of tyrosol, and tomato extracts had abundant epicatechin. The PCA analysis distinguished extracts based on in vitro antioxidant activity, phenol, carotenoid, and vitamin C content, along with their phenolic compound profiles. This study emphasizes the capacity of aqueous extract by-products as valuable sources of antioxidants and highlights the importance of understanding their bioactive components.