Main Pigment Research Articles

Quality attributes, antioxidant activity and color profile of orange-fleshed sweet potato grown in Vietnam

This study analyzed the nutritional composition, bioactive compounds, antioxidant activities and estimated potential renal acid load (PRAL) score of orange-fleshed sweet potato (OFSP) grown in Vietnam. In addition, important functional groups of carotenoid compounds in OFSP were identified by Fourier transform infrared spectroscopy (FTIR); carotenoid pigments were detected and quantified by high-performance liquid chromatography (HPLC). The results showed that, OFSP had outstanding physicochemical characteristics, containing many nutrients, bioactive substances, minerals and fiber. The negative PRAL score (< 0 mEq/day) of OFSP indicated that this was an alkaline food. FTIR spectroscopy provides a versatile tool for food analysis, and the analysis results showed that the carotenoid composition in OFSP grown in Vietnam have contained 14 complete functional groups detected, with 14 spectral peaks spanning the wavelength range from 433.98 cm−1 to 3288.63 cm−1. HPLC analysis identified the main carotenoid pigment in OFSP as β-carotene. The detailed evaluation of the physicochemical characteristics, functional groups and colorants in OFSP has shown that it is possible to use this raw material to develop different food products, playing a useful role in vitamin A deficiency management and improving the quality of human life.

Tyrosinases: a family of copper-containing metalloenzymes

Tyrosinases (TYRs) are a family of copper-containing metalloenzymes that are present in all domains of life. TYRs catalyze the reactions that start the biosynthesis of melanin, the main pigment of the animal kingdom, and are also involved in the formation of the bright colors seen on the caps of mushrooms and in the petals of flowers. TYRs catalyze the ortho-hydroxylation and oxidation of phenols and the oxidation of catechols to the respective o-quinones. They only need molecular oxygen to do that, and the products of TYRs—o-quinones—are highly reactive and will usually react with the next available nucleophile. This reactivity can be harnessed for pharmaceutical applications as well as in environmental and food biotechnology. The majority of both basic and applied research on TYRs utilizes “mushroom tyrosinase”, a crude enzyme preparation derived from button mushroom (Agaricus bisporus) fruiting bodies. Access to pure TYR preparations comes almost exclusively from the production of recombinant TYRs as the purification of these enzymes from the natural source is usually very laborious and plagued by low yields. In this text an introduction into the biochemistry of the enzyme TYR will be given, followed by an overview of available structural data of TYRs, the current model for the catalytic mechanism, a survey of reports on the recombinant production of this important metalloenzyme family, and a review of the applications of TYRs for the synthesis of catechols, as biosensors, in bioremediation, for the cross-linking of proteins and medical hydrogels as well as for melanoma treatment.Graphical

Hepatocellular carcinoma antibodies preferably identify nitro-oxidative-DNA lesions induced by 4-Chloro-orthophenylenediamine and DEANO

The widespread use of oxidative hair colouring cosmetics threatens public health. Phenylenediamine derivatives serve as the main pigment in permanent hair colours. They interact with biological macromolecules, altering their functional and structural physiology. The study aimed to investigate the effect of a typical synthetic hair dye pigment, 4-Chloro-orthophenylenediamine (4-Cl-OPD), under a nitrating environment of DEANO on the calf thymus DNA molecule. The results showed single-stranded regions, base/sugar-phosphate backbone alterations, molecular changes, and nitro-oxidative lesions. These modifications are referred to as neo-epitopes on the DNA molecule. IgGs from cancer patients with a history of permanent hair dye use were screened for the recognition of neo-epitopes on DNA molecules. Hepatocellular carcinoma IgG showed the highest binding with 56% inhibition in the competition ELISA. The immune complex formation was observed through electrophoretic mobility shift assay. In conclusion, synthetic hair dye users are likely to present with heightened immunological triggers under elevated nitric oxide levels. The study reports chronic hair dye exposure as one of the factors responsible for altering the intricacies of the DNA’s microarchitectural structure and inducing neo-epitopes on the molecule. The physiological status of NO may define the susceptibility towards 4-Cl-OPD and humoral response in hair dye users. Persistent nitro-oxidative stress due to 4-Cl-OPD and NO may induce a heightened immune response against neoepitopes in the nitro-oxidatively modified DNA. Therefore, chronic hair dye exposure may be identified as a risk to human health. These findings may contribute to a better understanding and reinforcement of hair dye as one of the modifiable risk factors responsible for the pro-inflammatory carcinogenic environment.

Antioxidant Activity of Anthocyanins and Anthocyanidins: A Critical Review.

Anthocyanins are the main plant pigments responsible for the color of flowers, fruits, and vegetative organs of many plants, and are applied also as safe food colorants. They are efficient antioxidants. In this review, the reactivity of anthocyanins and their aglycones, anthocyanidins, in the main antioxidant assays, and their reactions with reactive oxygen and nitrogen species, effects of interactions with other compounds and metal ions on the antioxidant activity of anthocyanins and the electrochemical properties of anthocyanins are presented. Numerous cases of attenuation of oxidative stress at the cellular and organismal levels by anthocyanins are cited. The direct and indirect antioxidant action of anthocyanins, the question of the specificity of anthocyanin action in complex extracts, as well as limitations of cellular in vitro assays and biomarkers used for the detection of antioxidant effects of anthocyanins, are critically discussed.

An unusual triplet population pathway in the Reaction Centre of the Chlorophyll-d binding Photosystem I of A. marina, as revealed by a combination of TR-EPR and ODMR spectroscopies

Photo-induced Chlorophyll (Chl) triplet states in the isolated Photosystem I (PSI) of Acaryochloris marina, that harbours Chl d as its main pigment, were investigated by Optically Detected Magnetic Resonance (ODMR) and Time-Resolved Electron Paramagnetic Resonance (TR-EPR), and as a function of pre-illumination of the sample under reducing redox poising. Fluorescence Detected Magnetic Resonance (FDMR) allowed resolving four Chl d triplet (3Chl d) populations (T1-T4) both in untreated and illuminated samples in the presence of ascorbate and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD). The FDMR signals increased following the pre-illumination treatment, particularly for the T3 and T4 populations, which are therefore sensitive to the redox state of PSI cofactors. Microwave-induced Triplet minus Singlet (TmS) spectra were detected in the |D|-|E| resonance window of the T3 and T4 triplets. These showed a broad singlet bleaching centred at 740 nm and also displayed complex spectral structure with several derivative-like features, indicating that both the T3 and T43Chl d populations are associated with the PSI reaction centre (RC) triplet, P3740. Parallel measurements by TR-EPR demonstrated that triplet signals observed under all conditions investigated are dominated by an electron spin polarisation (esp), which is typical of intersystem crossing, differently from what expected for recombination triplet states formed from a radical pair precursor. Moreover, stronger reductant conditions obtained by pre-illumination of the samples in the presence of dithionite and 5-methylphenazinium methyl sulfate (PMS) did not lead to a recombination triplet state esp, but rather to a decrease of the whole signal intensity. The energetics of A. marina PSI and the possible occurrence of distributions of cofactors redox properties are discussed in order to address the unexpected P3740 esp.

Rapid identification of phycobiliproteins in Porphyra yezoensis using near-infrared combined with convolutional neural network

Phycobiliproteins (PBPs) are the main pigment proteins and important indicators for evaluating the quality of Porphyra yezoensis (nori). This study aimed to develop a non-destructive and rapid method for determining PBP content (including total PBPs, phycoerythrin, phycocyanin, and allophycocyanin) in P. yezoensis, using near-infrared spectrum technology combined with a convolutional neural network (CNN), and to explore the influence of spectral preprocessing methods and machine learning algorithms on the predictive ability of the model. First, the spectral data was standardized using a combination of standard normal variable transformation and the first derivative to improve the accuracy and predictive ability of the model. We compared various models and determined that the CNN model performed better than conventional methods. After optimizing the number of convolutional layers, dropout rate, and learning rate, the performance of the CNN model was further improved. This study demonstrates the capability of the CNN model to leverage spectral data and solve regression problems to accurately measure PBPs. Moreover, for the first time, we established a functional equation between PBPs and P. yezoensis grades. This study provides a feasible and rapid method for the quantitative detection of PBPs in P. yezoensis.

Oil-in-water microemulsion of Arthrospira platensis carotenoid as antiphotooxidation in vitamin C beverages

Arthrospira platensis is a blue-green microalgae that has carotenoid as the main pigments, with the largest content being beta-carotene. Carotenoids are a type of pigment that is water insoluble, unstable, and has a limited bioavailability. One of the efforts to improve its solubility and stability, especially with regard to its anti-photooxidation capabilities, is to make it into a microemulsion. This study aimed to develop the most stable oil-in-water (O/W) microemulsion containing carotenoids from A. platensis for use as an antiphotooxidation agent in vitamin C beverages. Microemulsions consist of three distinct phases: oil, water and surfactant. The oil phase consisted of virgin coconut oil (VCO) or palm oil, with 7.5% and 15% and the aqueous phase was distilled water at a concentration of 65% or 80%. The surfactant used a combination of Tween 80, Tween 20, and Span 80 with a final hydrophilic-lipophilic balance or HLB value of 14.5. All microemulsion formulations were incubated for 24 hrs before being tested for stability by centrifugation at 3000 rpm for 30 mins, heating at 105oC for 5 hrs, and storage for 2 and 4 weeks. The resulting turbidity index was used to test the microemulsion's stability. The most stable microemulsion was chosen as a delivery system for carotenoid compounds. The carotenoid microemulsion was also tested by centrifugation, heating, and stability at different pH (6.5 and 4.2) and in varied ratios (1:1, 1:9 and 1:99). The results revealed that the concentration of oil and water phases in the microemulsion formulation influenced the microemulsion's stability. The best formulation obtained was a microemulsion with 7.5% of virgin coconut oil, 80% of water concentration, and surfactant with a ratio of 92:5.5:2.5 (Tween 80: Span 80:Tween 20). The most stable carotenoid microemulsion was a microemulsion with 100 ppm of carotenoid added. The carotenoid microemulsion was able to inhibit photooxidation at 4000 lux for 4 hrs. The vitamin C beverage model added with 6 ppm carotenoid microemulsion was able to inhibit photooxidation compared to the control and 12 ppm, for up to 6 hrs and there was a significant decrease in vitamin C and antioxidants after 24 hrs of photooxidation. A. platensis carotenoid microemulsion with a concentration of 6 ppm could inhibit photooxidation on vitamin C beverages for up to 6 hrs.

Recycling potato waste for the production of blue pigments by Streptomyces lydicus PM7 through submerged fermentation

BackgroundDiscarded potato is the most abundant potato waste and represents a worldwide disposal problem to the potato industry. This agricultural waste contains valuable nutrients that could be used as substrate to obtain diverse high value-added microbial products, such as biopigments. The aim of this work was to evaluate the use of discarded potato as a sole substrate source for producing blue pigments by Streptomyces lydicus PM7 through submerged fermentation.ResultsInitially, the traditional culture medium ISP2 was established as suitable for inoculum preparation, as it allowed high growth rates and consumption of ~ 75% reducing sugar, leading to 1.3 g L−1 dry biomass at 72 h of incubation. The formulated discarded potato broth (DPB) medium was evaluated together with five other traditional liquid culture media (potato dextrose broth, ISP2, ISP3, ISP4, and ISP5) for producing blue pigments by S. lydicus PM7. The highest blue pigment production was obtained by using DPB medium, reaching ~ 0.97 g L−1, followed by ISP5 (~ 0.36 g L−1). In terms of evaluating the concentration of discarded potato powder, the highest concentration of blue pigments was obtained with 16 g L−1, compared to concentrations of 4, 8, and 32 g L−1. In general, a notable increase in total proteins (~ 14 g L−1 in biomass; ~ 8 g L−1 in medium) and reducing sugars (~ 5 g L−1) on the fifth day of DPB fermentation was observed, at which time the production of blue pigments began. These data proved that S. lydicus PM7 is able to degrade potato wastes during submerged fermentation and to direct metabolism towards the formation of biopigments. Chromatographic analysis revealed that the main blue pigment produced by new strain in this complex medium is actinorhodin.ConclusionsDiscarded potato favored the production of blue pigments by S. lydicus PM7 under submerged fermentation, leading to final product concentration almost three times higher than others traditional Streptomyces culture media. To the best of our knowledge, this is the first report on the production of actinorhodin by the specie S. lydicus, as well as on this pigment synthesis based on an agricultural waste as a sole nutrient source for fermentation process. The findings showed that potato waste could be a potential byproduct for replacement of commercial culture media using for this same purpose.Graphical

Pigments profile and antioxidant potential of extremophile cyanobacteria isolated from the Mexican Volcanic Lake Chichonal

Cyanobacteria are ancient and prolific microorganisms for which the current knowledge remains limited. The present work constitutes the first report on the presence of the cyanobacteria Tolypothrix sp. LEGE 221228, Nostoc sp. LEGE 221229, Scytonema sp. LEGE 221230 and Drouetiella sp. LEGE 221231 in the volcanic crater lake in Chichonal (Chiapas-Mexico), and in the characterization of their pigments profile and antioxidant potential, through the application of biorefinery approaches. The identification of cyanobacteria species was achieved through advanced morphology-based methods for cyanobacterial taxonomy. The HPLC-PDA analysis of the cyanobacteria acetone extracts revealed β-carotene, echinenone and chlorophyll-a as the main pigments. Drouetiella sp. LEGE 221231 presented the highest β-carotene concentration (63.67 μg/mL), total carotenoids (87.92 μg/mL) and chlorophylls (20.88 μg/mL), closely followed by Tolypothrix sp. LEGE 221228 (with 51.37, 75.14 and 14.88 μg/mL, respectively), this being the first report on the carotenoid and chlorophylls profile of these strains. Aqueous extracts revealed the highest content of phycoerythrin in Tolypothrix sp. LEGE 221228 (50.61 mg/g) and of phycocyanin in Nostoc sp. LEGE 221229 (57.66 mg/g), standing out in superoxide anion radical scavenging, while the acetonic ones were more effective in scavenging nitric oxide radical. For both, Tolypothrix sp. LEGE 221228 was the most effective, presenting the lowest IC50 (53.75 and 57.68 μg/mL, respectively). Overall, the present study enriches the knowledge on biodiversity of cyanobacteria from underexplored environments, enhancing their potential biotechnological applications as producers of added value secondary metabolites with interest in food, pharmaceutical and cosmetic industries.

Experimental optical properties explained by density functional theory of the natural red algae for dye-sensitized solar cells application.

The present study investigates the usage of a novel natural dye derived from red algae of Morocco in dye-sensitized solar cells (DSSCs) for the first time. The main pigments responsible for sensitizing the semiconductor TiO2 coatings in the red algae were identified as phycoerythrin, carotenoid, and chlorophyll. The efficiency of a DSSC made from red algae was compared to that of a solar cell made from chlorophyll alone. The photovoltaic performance of the DSSC was evaluated through photocurrent density to photovoltage (J-V) characteristic analysis, and the efficiency was found to be 0.93%. To gain insights into its behavior, the absorbance and photoluminescence in a broad range were studied. Both absorbance and photoluminescence exhibited a broad-spectrum range. Additionally, electronic properties, such as HOMO, LUMO, energy gap, and chemical reactivity parameters, were studied using density functional theory (DFT) calculations.

Model of decomposition of the native absorption spectrum of Porphyridium purpureum culture

A model of the native absorption spectrum of the red seaweed Porphyridium purpureum culture was developed in this work. The mathematical model of each pigment is the sum of Gaussian curves. To level the light scattering, the spectra of the culture were recorded on a spectrophotometer with an integrating sphere. To verify the model, a series of parallel measurements of photosynthetic pigment concentrations using standard biochemical methods and the Gaussian curve method were performed. It was shown that the proposed model with sufficient accuracy makes it possible to determine the concentration of the main photosynthetic pigments of Porphyridium purpureum culture without interfering with its growth processes.

PHOTOSYNTHESIS OF WHEAT SEEDLINGS WHEN GROWN IN A MEDIUM WITH HEAVY METALS AND PECTIN

Pectins are considered as a means for cleaning reservoirs and soils from heavy metals due to their high adsorption properties. The aim of the study was to find out how the adding of pectins into the nutrient medium would affect the toxicity of heavy metals such as cadmium and zinc. It was found that cadmium at a concentration of 10-4 Mol and zinc at a concentration of 5 mMol inhibited the accumulation of biomass by plants of 10-day durum wheat seedlings (Triticum durum Desf.). Pectins mitigated this effect, but to a small extent. In addition, there was a slight increase in the proportion of roots in seedlings of the variant with heavy metals and pectin. The leaf area of the seedlings also decreased under the influence of heavy metals, young leaves suffered the most. The addition of pectins had a negative effect on the formation of the leaf surface, and a decrease in this indicator was noted. It has been shown that pectins contribute to an increase in the content of organic carbon in wheat plants, while the content of the main pigments of photosynthesis decreases. However, in variants with pectins, the photochemical activity of chloroplasts is maintained at a higher level than in solutions with heavy metals only.

Unveiling Polychrome Printing Methods on Textiles: Preliminary Results from the Mariano Fortuny y Madrazo Collection in Venice

At the beginning of the 20th century, the eclectic artist Mariano Fortuny y Madrazo patented two innovative methods for polychrome printing on fabrics and textiles, giving life to Fortuny fabric production in Venice. The first patent was related to colour application, while the second to a special machine that allows continuous printing using cylindrical rollers. Despite the descriptions, the methodology and materials used remain a secret. In collaboration with the Fortuny Museum in Venice, this research aimed at studying and identifying the different steps of Fortuny printing methodologies. Printing matrices, fabrics and raw materials found in the artist’s studio were analysed in a multi-analytical campaign through digital microscopy, X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy in attenuated total reflectance (FTIR-ATR), μ-Raman spectroscopy and gas chromatography–mass spectrometry (GC–MS). Three main pigments were identified in paper samples: ivory black, a copper-based pigment, and a carbon black pigment with ultramarine for blues. The pigments were bound with linseed oil and colophony in varying proportions. Polychrome silk fabrics were dyed with a base colour, and then the coloured patterns were superimposed by continuous printing. Prussian blue was identified as one of the textile inks. Results provided a better understanding of printing methodology.

Effects of cell morphology, physiology, biochemistry and CHS genes on four flower colors of Impatiens uliginosa.

Flower color is one of the important ornamental traits in the plants, which plays an active role in attracting pollinators to pollinate plants and reproduce their offspring. The flower color of Impatiens uliginosa is rich, there are four main flower colors in nature: deep red, red, pink, and white. However, it remains unclear whether on four different flower colors mechanism of I. uliginosa. We investigate colorimetric measurement, observation of epidermal cells, cellular pH determination, extraction and determination of total anthocyanins and flavonoid, semi-quantitative determination of pigment components, and gene cloning and qRT-PCR of CHS genes to study four flower colors of I. uliginosa. The L* and b* values were the highest in white flower, while the a* values were the highest in pink flower. The same shape of epidermal cells was observed in different flower colors, which was all irregular flat polygons, and there were partial lignification. Their cellular pH values were weakly acidic, while the pH values of the deep red flower was the highest and the white flower was the lowest. The highest pigment content of the four flower colors was total anthocyanin content. And malvidin-3-galactosidechloride (C23H25ClO12), cyanidin-3-O-glucoside (C21H21O11) and delphinidin (C15H11O7) were the main pigment components affecting the color of four different flower colors. The anthocyanin synthesis gene IuCHS was expressed in four flowers, and all three copies of it had the highest expression level in pink flower and the lowest expression level in white flower. These results revealed the influence of main internal factors on four different flower colors of I. uliginosa, and provided a basis for further understanding of the intracellular and molecular regulatory mechanisms of flower color variation, and laid a foundation for the improvement of flower color breeding of Impatiens.

Solvent selection for anthrocyanin dye extraction from Kigelia Africana and Hibiscus sabdariffa for dye sensitized solar cells

The main flavonoid pigment in the petals of Kigelia Africana and the calyx of Hibiscus sabdariffa is anthocyanin, responsible for the vibrant red, maroon, and purple hues in flowers. This pigment can modulate incident light on flowers, prompting its selection for detailed investigation. TiO2 nanostructures were synthesized using a one-step hydrothermal method, revealing the formation of nanorods and a single-phase rutile structure through FESEM and XRD analyses, respectively. The study aimed to assess the impact of various solvents on the extraction of natural dyes, which were subsequently sensitized on TiO2 photoanodes for DSSC applications. Four solvents-water, water with HCl, ethanol, and citric acid were employed to extract natural dyes from Kigelia Africana's petals and Hibiscus sabdariffa's calyx. Notably, dyes extracted with citric acid demonstrated promising results. The conversion efficiency of DSSCs fabricated with Kigelia Africana dye and Hibiscus sabdariffa dye, extracted using citric acid as the solvent, was found to be 0.87 % and 0.92 %, respectively. The implications of these findings are discussed.

Restorative antiaging influence and chemical profile of Prunus domestica L. (European plum) seed extract in a D-galactose-induced rat model

Background Prunus domestica L., also known as European plums or prunes, is a member of the Rosaceae family. Recently, fruit byproducts like seeds have been used as a novel and affordable source of bioactive compounds that may be an affordable source of substances. These substances hold potential benefit to the food and pharmaceutical industries. Objective The study aims to evaluate the chemical composition of P. domestica L. seeds and their safety and efficiency as an antiaging agent. Materials and methods The phenolic content in ethanolic seed extract was determined using the Folin–Ciocalteu reagent. Chlorophyll a, chlorophyll b, and β-carotene concentrations were measured by high performance liquid chromatography analysis. Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) negative ion mode was carried out to investigate the phytoconstituents, in addition to the isolation of the main active compounds on preparative TLC as well as evaluation of cognitive capabilities, measurement of antioxidants and neurotransmitters and histopathological brain examination. Results and conclusion The total phenolic and flavonoid contents of ethanolic extract were 136.55 mg GAE/g and 89 mg CE/g, respectively. Also, high performance liquid chromatography analysis led to the identification of β-carotene as the main natural pigment (59.376 mg/100 g), followed by chlorophyll b (41.745 mg/100 g) and finally chlorophyll a (20.824 mg/100 g). In addition, UPLC/ESI-MS analysis using the negative ion mode led to the identification of 24 compounds, including two flavonols, one flavanone, two flavones, 10 flavonoid-O-glycosides, two methylated flavonoids, one isoflavonoidC-glycosides, two phenolic acids, two aldehydes, one stilbene, and one coumarin. Preparative TLC chromatographic technique for ethanolic P. domestica seed extract resulted in the isolation of γ-tocopherol, kaempferol-3-O-rutinoside, luteolin, and luteolin-7-O-glucoside. The ethanolic extract proved to have a remarkable scavenging effect against 1,1-Diphenyl-2-picryl-hydrazyl in a dose-dependent manner compared with vitamin C. Improvement in behavioral assessment was noticed posttreatment of rats with the extract suggesting amelioration in cognitive ability and spatial memory of rats compared with standard drug. In addition, noticeable improvements were observed in neurotransmitter levels, acetylcholinesterase, noradrenaline, dopamine, and serotonin, in the brain tissue of aged rats. Besides, remarkable improvements in oxidative stress biomarkers (nitric oxide, reduced glutathione and lipid peroxide, total antioxidant capacity) and in histopathological pictures of different brain regions posttreatment of aged rats with the extract compared with donepezil standard drug were recorded.

Color components determination and full-length comparative transcriptomic analyses reveal the potential mechanism of carotenoid synthesis during Paphiopedilum armeniacum flowering.

Paphiopedilum armeniacum (P. armeniacum), an ornamental plant native to China, is known for its distinctive yellow blossoms. However, the mechanisms underlying P. armeniacum flower coloration remain unclear. We selected P. armeniacum samples from different flowering stages and conducted rigorous physicochemical analyses. The specimens were differentiated based on their chemical properties, specifically their solubilities in polar solvents. This key step enabled us to identify the main metabolite of flower color development of P. armeniacum, and to complete the identification by High-performance liquid chromatography (HPLC) based on the results. Additionally, we employed a combined approach, integrating both third-generation full-length transcriptome sequencing and second-generation high-throughput transcriptome sequencing, to comprehensively explore the molecular components involved. We combined physical and chemical analysis with transcriptome sequencing to reveal that carotenoid is the main pigment of P. armeniacum flower color. Extraction colorimetric method and HPLC were used to explore the characteristics of carotenoid accumulation during flowering. We identified 28 differentially expressed carotenoid biosynthesis genes throughout the flowering process, validated their expression through fluorescence quantification, and discovered 19 potential positive regulators involved in carotenoid synthesis. Among these candidates, three RCP2 genes showed a strong potential for governing the PDS and ZDS gene families. In summary, our study elucidates the fundamental mechanisms governing carotenoid synthesis during P. armeniacum flowering, enhancing our understanding of this process and providing a foundation for future research on the molecular mechanisms driving P. armeniacum flowering.

Polyphasic description of Ciimarium marinum gen. et sp. nov. (Prochlorococcaceae, Synechococcales): a new picocyanobacterial taxon from the Portuguese coastal ecosystem

In this paper, we describe Ciimarium marinum gen. et sp. nov. (Prochlorococcaceae, Synechococcales) based on 16S rRNA gene phylogenies, 16S-23S ITS secondary structures, ultrastructure (TEM), morphological, pigments and ecological data of “Synechococcus” sp. LEGE 11466. The strain was isolated from a sample collected at Leixões Harbour, Portugal (41°11’08.1”N 8°43’08.8”W) on September 26th, 2011, by scraping an epilithic biofilm under 10-13m depth, less than 1km offshore. Bayesian Inference and Maximum Likelihood phylogenies demonstrate that the Ciimarium sequence is placed in a monophyletic clade with strong phylogenetic support (BI=1, ML=100), within the Prochlorococcaceae cluster. The type strain LEGE 11466 is phylogenetically distant from other reference strains of Cyanobacteria and is grouped with Uncultured “Synechococcus” MLS1228cl3 , “Synechococcus” MLCB, “Cyanobium” ATX 6A2 ATX-6A2-C45 and “Synechococcus” MBIC10613.. The secondary structures of 16S-23S ITS corroborate with the separation of Ciimarium from all the Prochlorococcaceae genera. Also, they show that MLCB and ATX 6A2 ATX-6A2-C45 may be different species from the type LEGE 11466. The ultrastructure analysis shows parietal thylakoids, in agreement with the family description. Morphologically the genus is indistinguishable from other Prochlorococcaceae genera. The pigments analysis shows Zeaxanthin and β-carotene as the main pigments, and also a low concentration of phycocyanin. Finally, our phylogenies indicate that a revision of the Prochlorococcaceae family is necessary, as there are still many Synechococcus-like Cyanobacteria strains that should be described as new genera in the future.

A multiplex metabolomic approach for quality control of Spirulina supplement and its allied microalgae (Amphora & Chlorella) assisted by chemometrics and molecular networking

Microalgae species are of economic importance regarded as “green gold” being rich in bioactive compounds. Spirulina and Chlorella are the most popular microalgal species and are marketed as healthy food supplements. At the same time, Amphora holds potential as a source of healthy lipids and essential fatty acids. Yet, there are considerable variations in their reported chemical composition, and less is known about their compositional differences. A multiplexed metabolomic approach was adopted for the quality control (QC) of Spirulina supplements and to compare its constitutive metabolome to Chlorella and Amphora. The adopted protocol comprised gas chromatography-mass spectrometry (GC–MS), ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UPLC-HRMS/MS), and ultraviolet–visible spectrophotometry (UV/Vis) for mapping their primary and secondary metabolome. Interestingly, UPLC-HRMS/MS analysis delineated the abundance of fatty acids in Amphora versus glycolipids enrichment in Spirulina, and porphyrins were the main pigments identified in Spirulina, with scarce occurrence in Chlorella. Orthogonal projections to latent structures discriminant analysis (OPLS-DA) analysis of GC–MS data set revealed palmitic acid, 3-mannobiose, and glyceryl-glycoside as being most enriched in Spirulina, versus sucrose and leucine in Chlorella and Amphora, respectively. Despite being of low discriminatory potential, UV/Vis OPLS-DA modeling showed that Spirulina was distinguished with the UV absorbances of carotenoids and chlorophyll pigments, as indicated by its OPLS-DA derived S-plot. Our study provides a QC approach for the analysis of the microalgal species and poses alternative spectral and compositional markers for their discrimination.

The Structure, Functions and Potential Medicinal Effects of Chlorophylls Derived from Microalgae.

Microalgae are considered to be natural producers of bioactive pigments, with the production of pigments from microalgae being a sustainable and economical strategy that promises to alleviate growing demand. Chlorophyll, as the main pigment of photosynthesis, has been widely studied, but its medicinal applications as an antioxidant, antibacterial, and antitumor reagent are still poorly understood. Chlorophyll is the most important pigment in plants and algae, which not only provides food for organisms throughout the biosphere, but also plays an important role in a variety of human and man-made applications. The biological activity of chlorophyll is closely related to its chemical structure; its specific structure offers the possibility for its medicinal applications. This paper reviews the structural and functional roles of microalgal chlorophylls, commonly used extraction methods, and recent advances in medicine, to provide a theoretical basis for the standardization and commercial production and application of chlorophylls.