Carotenoids from Marine Organisms: Biological Functions and Industrial Applications

A marine-derived antioxidant astaxanthin as a potential neuroprotective and neurotherapeutic agent: A review of its efficacy on neurodegenerative conditions

Astaxanthin is a potent lipid-soluble carotenoid produced by several different freshwater and marine microorganisms, including microalgae, bacteria, fungi, and yeast. The proven therapeutic effects of astaxanthin against different diseases have made this carotenoid popular in the nutraceutical market and among consumers. Recently, astaxanthin is also receiving attention for its effects in the co-adjuvant treatment or prevention of neurological pathologies. In this systematic review, studies evaluating the efficacy of astaxanthin against different neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, cerebrovascular diseases, and spinal cord injury are analyzed. Based on the current literature, astaxanthin shows potential biological activity in both in vitro and in vivo models. In addition, its preventive and therapeutic activities against the above-mentioned diseases have been emphasized in studies with different experimental designs. In contrast, none of the 59 studies reviewed reported any safety concerns or adverse health effects as a result of astaxanthin supplementation. The preventive or therapeutic role of astaxanthin may vary depending on the dosage and route of administration. Although there is a consensus in the literature regarding its effectiveness against the specified diseases, it is important to determine the safe intake levels of synthetic and natural forms and to determine the most effective forms for oral intake.

Unraveling radiation resistance strategies in two bacterial strains from the high background radiation area of Chavara-Neendakara: A comprehensive whole genome analysis

This paper reports the results of gamma irradiation experiments and whole genome sequencing (WGS) performed on vegetative cells of two radiation resistant bacterial strains, Metabacillus halosaccharovorans (VITHBRA001) and Bacillus paralicheniformis (VITHBRA024) (D10 values 2.32 kGy and 1.42 kGy, respectively), inhabiting the top-ranking high background radiation area (HBRA) of Chavara-Neendakara placer deposit (Kerala, India). The present investigation has been carried out in the context that information on strategies of bacteria having mid-range resistance for gamma radiation is inadequate. WGS, annotation, COG and KEGG analyses and manual curation of genes helped us address the possible pathways involved in the major domains of radiation resistance, involving recombination repair, base excision repair, nucleotide excision repair and mismatch repair, and the antioxidant genes, which the candidate could activate to survive under ionizing radiation. Additionally, with the help of these data, we could compare the candidate strains with that of the extremely radiation resistant model bacterium Deinococccus radiodurans, so as to find the commonalities existing in their strategies of resistance on the one hand, and also the rationale behind the difference in D10, on the other. Genomic analysis of VITHBRA001 and VITHBRA024 has further helped us ascertain the difference in capability of radiation resistance between the two strains. Significantly, the genes such as uvsE (NER), frnE (protein protection), ppk1 and ppx (non-enzymatic metabolite production) and those for carotenoid biosynthesis, are endogenous to VITHBRA001, but absent in VITHBRA024, which could explain the former's better radiation resistance. Further, this is the first-time study performed on any bacterial population inhabiting an HBRA. This study also brings forward the two species whose radiation resistance has not been reported thus far, and add to the knowledge on radiation resistant capabilities of the phylum Firmicutes which are abundantly observed in extreme environment.

Astaxanthin Supplementation as a Potential Strategy for Enhancing Mitochondrial Adaptations in the Endurance Athlete: An Invited Review

Astaxanthin, a potent antioxidant found in marine organisms such as microalgae and krill, may offer ergogenic benefits to endurance athletes. Originally used in fish feed, astaxanthin has shown a greater ability to mitigate various reactive oxygen species and maintain the structural integrity of mitochondria compared to other exogenous antioxidants. More recent work has shown that astaxanthin may improve: (1) cycling time trial performance, (2) cardiorespiratory measures such as submaximal heart rate during running or cycling, (3) recovery from delayed-onset muscle soreness, and (4) endogenous antioxidant capacity such as whole blood glutathione within trained populations. In this review, the history of astaxanthin and its chemical structure are first outlined before briefly describing the various adaptations (e.g., mitochondrial biogenesis, enhanced endogenous antioxidant capacity, etc.) which take place specifically at the mitochondrial level as a result of chronic endurance training. The review then concludes with the potential additive effects that astaxanthin may offer in conjunction with endurance training for the endurance athlete and offers some suggested practical recommendations for athletes and coaches interested in supplementing with astaxanthin.

Impacts of astaxanthin-enriched Paracoccus carotinifaciens on growth, immune responses, and reproduction performance of broodstock Nile tilapia during winter season

The growth, immune response, and reproductive performance of broodstock of Nile tilapia (Oreochromis niloticus) under winter stress conditions were investigated the effects of supplementary diets with astaxanthin-enriched Paracoccus carotinifaciens. Throughout an eight-week period in the winter season, male and female tilapia were fed with diets containing different levels of P. carotinifaciens dietary supplementation: 0 g/kg (T1; control), 5 g/kg (T2), 10 g/kg (T3), and 20 g/kg (T4). Subsequently, a four-week mating system was implemented during the winter stress period. The results revealed that there were no significant differences observed in growth, hematological indices, and blood chemical profiles among all treatment groups for both male and female tilapia. However, a significant increase in cholesterol content was noted in both male and female tilapia fed with the T4 diet (p<0.05). The total carotenoid content in the muscle was evaluated, and significantly higher values were found in both male and female tilapia that fed T4 supplementation (p<0.05). Moreover, immunological parameters such as myeloperoxidase and antioxidant parameters in the liver including superoxide dismutase activity and catalase enzyme activity showed significant increases in tilapia fed with the T4 diet. The impact of P. carotinifaciens supplementation on broodstock tilapia indicated a significant increase in spermatozoa concentration in males and increased egg production in females after consumption of the T4 diet (p<0.05). Thus, this study highlighted that the presence of astaxanthin-enriched P. carotinifaciens in the diet of broodstock Nile tilapia can lead to the accumulation of carotenoids in their muscle tissue, improvement in antioxidant status, enhancement of immune function, and potential enhancement of reproductive capabilities, even under overwintering conditions.

Sources of Carotenoids in Amazonian Fruits

Epidemiological studies have shown that a diet rich in bioactive components significantly reduces cardiovascular disease incidence and mortality. In this sense, there is a need for meta-analytical research that confirms this phenomenon and increases specific knowledge about certain bioactive compounds such as carotenoids. Thus, this systematic review and meta-analysis aim to disseminate knowledge about the sources of carotenoids in fruit consumed in the north of Brazil which are outside the Brazilian trade balance. A systematic review and a meta-analysis following the PRISMA guidelines were conducted based on a random effects synthesis of multivariable-adjusted relative risks (RRs). Searches of seven sources were carried out, including PubMed, Science Direct from Elsevier, Web of Science, Scielo, Eric Research and Google Scholar databases. The systematic review was guided by a systematic review protocol based on the POT strategy (population, outcome and type of study) adapted for use in this research. Mendeley was a resource used to organize and manage references and exclude duplicates of studies selected for review. In this review, we present the potential bioactive compounds concentrated in little-known fruit species from the Amazon and their benefits. Consuming fruits that are rich in notable constituents such as carotenoids is important for the prevention of chronic non-communicable diseases through anti-inflammatory and anticoagulant properties, as well as antivirals, immunomodulators and antioxidants agents that directly affect the immune response.

Zeaxanthin epoxidase 3 Knockout Mutants of the Model Diatom Phaeodactylum tricornutum Enable Commercial Production of the Bioactive Carotenoid Diatoxanthin

Carotenoids are pigments that have a range of functions in human health. The carotenoid diatoxanthin is suggested to have antioxidant, anti-inflammatory and chemo-preventive properties. Diatoxanthin is only produced by a few groups of microalgae, where it functions in photoprotection. Its large-scale production in microalgae is currently not feasible. In fact, rapid conversion into the inactive pigment diadinoxanthin is triggered when cells are removed from a high-intensity light source, which is the case during large-scale harvesting of microalgae biomass. Zeaxanthin epoxidase (ZEP) 2 and/or ZEP3 have been suggested to be responsible for the back-conversion of high-light accumulated diatoxanthin to diadinoxanthin in low-light in diatoms. Using CRISPR/Cas9 gene editing technology, we knocked out the ZEP2 and ZEP3 genes in the marine diatom Phaeodactylum tricornutum to investigate their role in the diadinoxanthin-diatoxanthin cycle and determine if one of the mutant strains could function as a diatoxanthin production line. Light-shift experiments proved that ZEP3 encodes the enzyme converting diatoxanthin to diadinoxanthin in low light. Loss of ZEP3 caused the high-light-accumulated diatoxanthin to be stable for several hours after the cultures had been returned to low light, suggesting that zep3 mutant strains could be suitable as commercial production lines of diatoxanthin.

In Silico and In Vitro multiple analysis approach for screening naturally derived ligands for red seabream aryl hydrocarbon receptor

The aryl hydrocarbon receptor (AHR) is a key ligand-dependent transcription factor that mediates the toxic effects of compounds such as dioxin. Recently, natural ligands of AHR, including flavonoids, have been attracting physiological and toxicological attention as they have been reported to regulate major biological functions such as inflammation and anti-cancer by reducing the toxic effects of dioxin. Additionally, it is known that natural AHR ligands can accumulate in wildlife tissues, such as fish. However, studies in fish have investigated only a few ligands in experimental fish species, and the AHR response of marine fish to natural AHR ligands of various other structures has not been thoroughly investigated. To explore various natural AHR ligands in marine fish, which make up the most fish, it is necessary to develop new screening methods that consider the specificity of marine fish. In this study, we investigated the response of natural ligands by constructing in vitro and in silico experimental systems using red seabream as a model species. We attempted to develop a new predictive model to screen potential ligands that can induce transcriptional activation of red seabream AHR1 and AHR2 (rsAHR1 and rsAHR2). This was achieved through multiple analyses using in silico/ in vitro data and Tox21 big data. First, we constructed an in vitro reporter gene assay of rsAHR1 and rsAHR2 and measured the response of 10 representatives natural AHR ligands in COS-7 cells. The results showed that FICZ, Genistein, Daidzein, I3C, DIM, Quercetin and Baicalin induced the transcriptional activity of rsAHR1 and rsAHR2, while Resveratrol and Retinol did not induce the transcriptional activity of rsAHR isoforms. Comparing the EC50 values of the respective compounds in rsAHR1 and rsAHR2, FICZ, Genistein, and Daidzein exhibited similar isoform responses, but I3C, Baicalin, DIM and Quercetin show the isoform-specific responses. These results suggest that natural AHR ligands have specific profiling and transcriptional activity for each rsAHR isoform. In silico analysis, we constructed homology models of the ligand binding domains (LBDs) of rsAHR1 and rsAHR2 and calculated the docking energies (U_dock values) of natural ligands with measured in vitro transcriptional activity and dioxins reported in previous studies. The results showed a significant correlation (R2=0.74(rsAHR1), R2=0.83(rsAHR2)) between docking energy and transcriptional activity (EC50) value, suggesting that the homology model of rsAHR1 and rsAHR2 can be utilized to predict the potential transactivation of ligands. To broaden the applicability of the homology model to diverse compound structures and validate the correlation with transcriptional activity, we conducted additional analyses utilizing Tox21 big data. We calculated the docking energy values for 1860 chemicals in both rsAHR1 and rsAHR2, which were tested for transcriptional activation in Tox21 data against human AHR. By comparing the U_dock energy values between 775 active compounds and 1085 inactive compounds, a significant difference (p<0.001) was observed between the U_dock energy values in the two groups, suggesting that the U_dock value can be applied to distinguish the activation of compounds. Furthermore, we observed a significant correlation (R2=0.45) between the AC50 of Tox21 database and U_dock values of human AHR model. In conclusion, we calculated equations to translate the results of an in silico prediction model for ligand screening of rsAHR1 and rsAHR2 transactivation. This ligand screening model can be a powerful tool to quantitatively estimate AHR transactivation of major marine agents to which red seabream may be exposed. The study introduces a new screening approach for potential natural AHR ligands in marine fish, based on homology model-docking energy values of rsAHR1 and rsAHR2, with implications for future agonist development and applications bridging in silico and in vitro data.

Different therapeutic approaches in melasma: advances and limitations

Melasma is a chronic hyperpigmentation skin disorder that is more common in the female gender. Although melasma is a multifactorial skin disorder, however, sun-exposure and genetic predisposition are considered as the main etiologic factors in melasma occurrence. Although numerous topical and systemic therapeutic agents and also non-pharmacologic procedural treatments have been considered in melasma management, however, the commonly available therapeutic options have several limitations including the lack of sufficient clinical effectiveness, risk of relapse, and high rate of unwanted adverse drug reactions. Recruitment of nanotechnology for topical drug delivery in melasma management can lead to enhanced skin penetration, targeted drug delivery to the site of action, longer deposition at the targeted area, and limit systemic absorption and therefore systemic availability and adverse drug reactions. In the current review, first of all, the etiology, pathophysiology, and severity classification of melasma have been considered. Then, various pharmacologic and procedural therapeutic options in melasma treatment have been discussed. Afterward, the usage of various types of nanoparticles for the purpose of topical drug delivery for melasma management was considered. In the end, numerous clinical studies and controlled clinical trials on the assessment of the effectiveness of these novel topical formulations in melasma management are summarized.

Selenium-Induced Enhancement in Growth and Rhizosphere Soil Methane Oxidation of Prickly Pear

As an essential element for plants, animals, and humans, selenium (Se) has been shown to participate in microbial methane oxidation. We studied the growth response and rhizosphere methane oxidation of an economic crop (prickly pear, Rosa roxburghii Tratt) through three treatments (Se0.6 mg/kg, Se2.0 mg/kg, and Se10 mg/kg) and a control (Se0 mg/kg) in a two-month pot experiment. The results showed that the height, total biomass, root biomass, and leaf biomass of prickly pear were significantly increased in the Se0.6 and Se2.0 treatments. The root-to-shoot ratio of prickly pear reached a maximum value in the Se2 treatment. The leaf carotenoid contents significantly increased in the three treatments. Antioxidant activities significantly increased in the Se0.6 and Se2 treatments. Low Se contents (0.6, 2 mg/kg) promoted root growth, including dry weight, length, surface area, volume, and root activity. There was a significant linear relationship between root and aboveground Se contents. The Se translocation factor increased as the soil Se content increased, ranging from 0.173 to 0.288. The application of Se can improve the state of rhizosphere soil's organic C and soil nutrients (N, P, and K). Se significantly promoted the methane oxidation rate in rhizosphere soils, and the Se10 treatment showed the highest methane oxidation rate. The soil Se gradients led to differentiation in the growth, rhizosphere soil properties, and methane oxidation capacity of prickly pear. The root Se content and Se translocation factor were significantly positively correlated with the methane oxidation rate. Prickly pear can accumulate Se when grown in Se-enriched soil. The 2 mg/kg Se soil treatment enhanced growth and methane oxidation in the rhizosphere soil of prickly pear.

Metagenomic Analysis of Antarctic Ocean near the King Sejong Station Reveals the Diversity of Carotenoid Biosynthetic Genes

Carotenoids, biotechnologically significant pigments, play crucial biological roles in marine microorganisms. While various environments have been explored to understand the diversity of carotenoids and their biosynthesis, the Antarctic Ocean remains relatively under-investigated. This study conducted a metagenomic analysis of seawater from two depths (16 and 25 m) near the King Sejong Station in the Antarctic Ocean. The analysis revealed a rich genetic diversity underlying C40 (astaxanthin, myxol, okenone, spheroidene, and spirilloxanthin), C30 (diaponeurosporene, diapolycopene, and staphyloxanthin), and C50 (C.p. 450) carotenoid biosynthesis in marine microorganisms, with notable differential gene abundances between depth locations. Exploring carotenoid pathway genes offers the potential for discovering diverse carotenoid structures of biotechnological value and better understanding their roles in individual microorganisms and broader ecosystems.

The association between several serum micronutrients and benign prostatic hyperplasia: Results from NHANES 2003-2006

BACKGROUND

Benign prostatic hyperplasia (BPH) is a common condition that affects the quality of life of older men. Specific micronutrients, including retinol, retinyl esters, carotenoids, vitamin E, and vitamin C, have antioxidant and anti-inflammatory properties. However, the correlation between serum concentrations of these micronutrients and BPH is unclear.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES), which included 2067 representative US men. BPH was assessed using the self-reported questionnaire. This association was explored by adjusting for confounders using multivariate logistic regression.

RESULTS

After fully adjusting for confounders, for every 0.01 μmol/L increase in serum retinyl esters, the risk of BPH increased by 2% (OR = 1.02; 95% CI: 1.01-1.03; p = 0.006). Based on the Bonferroni-corrected p-value, we found this correlation to be significant. One μmol/L increase in total carotenoids was associated with a 22% increase in BPH risk (OR = 1.22; 95% CI: 1.03-1.46; p = 0.025). By analyzing the correlation between different types of carotenoids and BPH, we also found that β-carotenoids (OR = 1.43; 95% CI: 1.03-1.99; p = 0.036) was also positively correlated with BPH. The subgroup analysis revealed a positive correlation between serum vitamin E (OR = 1.02; 95% CI: 1.00-1.04; p = 0.018) and BPH in men under 60 years of age. Serum retinyl ester (OR = 1.02; 95% CI: 1.01-1.04; p = 0.008) and carotenoid (OR = 1.52; 95% CI: 1.22-1.87; p < 0.001) concentrations were positively correlated with BPH in men over 60 years of age.

CONCLUSION

Our study suggests that excessive serum retinyl esters, total carotenoids, and especially β-carotenoids are potential risk factors for BPH, and this association should be further investigated.

Characterization and biological applications of gonadal extract of Paracentrotus lividus collected along the Mediterranean coast of Alexandria, Egypt

Marine invertebrates represent a valuable reservoir of pharmaceutical bioactive compounds with potential relevance to various medical applications. These compounds exhibit notable advantages when compared to their terrestrial counterparts, in terms of their potency, activity, and mechanism of action. Within this context, the present work aimed to extract, chemically characterize, and investigate the bioactivity of the gonadal extract of the sea urchin Paracentrotus lividus (P. lividus) collected along the Mediterranean coast of Alexandria, Egypt. Fractions of the gonadal extract were characterized by Spectrophotometry and gas chromatography-mass spectrometry (GC-MS), and their bioactivities were investigated in vitro. The analysis supported the extract richness of carotenoids and bioactive compounds. The extract showed promising anticancer activity against three different breast cancer cell lines with different levels of aggressiveness and causative factors, namely MDA-MB-231, MDA-MB-453, and HCC-1954. Gene expression analysis using RT-qPCR showed that P. lividus extract inhibited the expression of crucial factors involved in cell cycle regulation and apoptosis. In addition, the extract significantly inhibited the lipo-polysaccharides (LPS) induced inflammation in the RAW264.7 macrophage cell line and exerted anti-bacterial activity against the Gram-negative bacteria Klebsiella pneumoniae and Pseudomonas aeruginosa. Collectively, these results demonstrated the chemical richness and the wide-scale applicability of P. lividus gonadal extract as an anti-cancer, anti-bacterial, and anti-inflammatory natural extract.

Microbial pigments: Sources, current status, future challenges in cosmetics and therapeutic applications

Color serves as the initial attraction and offers a pleasing aspect. While synthetic colorants have been popular for many years, their adverse environmental and health effects cannot be overlooked. This necessitates the search for natural colorants, especially microbial colorants, which have proven and more effective. Pigment-producing microorganisms offer substantial benefits. Natural colors improve product marketability and bestow additional benefits, including antioxidant, antiaging, anticancer, antiviral, antimicrobial, and antitumor properties. This review covers the various types of microbial pigments, the methods to enhance their production, and their cosmetic and therapeutic applications. We also address the challenges faced during the commercial production of microbial pigments and propose potential solutions.

Understanding Macroalgae: A Comprehensive Exploration of Nutraceutical, Pharmaceutical, and Omics Dimensions

Driven by a surge in global interest in natural products, macroalgae or seaweed, has emerged as a prime source for nutraceuticals and pharmaceutical applications. Characterized by remarkable genetic diversity and a crucial role in marine ecosystems, these organisms offer not only substantial nutritional value in proteins, fibers, vitamins, and minerals, but also a diverse array of bioactive molecules with promising pharmaceutical properties. Furthermore, macroalgae produce approximately 80% of the oxygen in the atmosphere, highlighting their ecological significance. The unique combination of nutritional and bioactive attributes positions macroalgae as an ideal resource for food and medicine in various regions worldwide. This comprehensive review consolidates the latest advancements in the field, elucidating the potential applications of macroalgae in developing nutraceuticals and therapeutics. The review emphasizes the pivotal role of omics approaches in deepening our understanding of macroalgae's physiological and molecular characteristics. By highlighting the importance of omics, this review also advocates for continued exploration and utilization of these extraordinary marine organisms in diverse domains, including drug discovery, functional foods, and other industrial applications. The multifaceted potential of macroalgae warrants further research and development to unlock their full benefits and contribute to advancing global health and sustainable industries.

Fungi-derived natural antioxidants

In humans, exogenous antioxidants aid the endogenous antioxidant system to detoxify excess ROS generated during oxidative stress, thereby protecting the body against various diseases and stressful conditions. The majority of natural antioxidants available on the consumer market are plant-based; however, fungi are being recognized as alternative sources of various natural antioxidants such as polysaccharides, pigments, peptides, sterols, phenolics, alkaloids, and flavonoids. In addition, some exogenous antioxidants are exclusively found in fungi. Fungi-derived antioxidants exhibit scavenging activities against DPPH, ABTS, hydroxyl, superoxide, hydrogen peroxide, and nitric oxide radicals in vitro. Furthermore, in vivo models, application of fungal-derived antioxidants increase the level of various antioxidant enzymes, such as catalases, superoxide dismutases, and glutathione peroxidases, and reduce the level of malondialdehyde. Therefore, fungi-derived antioxidants have potential to be used in the food, cosmetic, and pharmaceutical industries. This review summarizes the antioxidant potential of different fungi (mushrooms, yeasts, and molds)-derived natural compounds such as polysaccharides, pigments, peptides, ergothioneine, ergosterol, phenolics, alkaloids, etc.

Pan-genome analysis of six Paracoccus type strain genomes reveal lifestyle traits

The genus Paracoccus capable of inhabiting a variety of different ecological niches both, marine and terrestrial, is globally distributed. In addition, Paracoccus is taxonomically, metabolically and regarding lifestyle highly diverse. Until now, little is known on how Paracoccus can adapt to such a range of different ecological niches and lifestyles. In the present study, the genus Paracoccus was phylogenomically analyzed (n = 160) and revisited, allowing species level classification of 16 so far unclassified Paracoccus sp. strains and detection of five misclassifications. Moreover, we performed pan-genome analysis of Paracoccus-type strains, isolated from a variety of ecological niches, including different soils, tidal flat sediment, host association such as the bluespotted cornetfish, Bugula plumosa, and the reef-building coral Stylophora pistillata to elucidate either i) the importance of lifestyle and adaptation potential, and ii) the role of the genomic equipment and niche adaptation potential. Six complete genomes were de novo hybrid assembled using a combination of short and long-read technologies. These Paracoccus genomes increase the number of completely closed high-quality genomes of type strains from 15 to 21. Pan-genome analysis revealed an open pan-genome composed of 13,819 genes with a minimal chromosomal core (8.84%) highlighting the genomic adaptation potential and the huge impact of extra-chromosomal elements. All genomes are shaped by the acquisition of various mobile genetic elements including genomic islands, prophages, transposases, and insertion sequences emphasizing their genomic plasticity. In terms of lifestyle, each mobile genetic elements should be evaluated separately with respect to the ecological context. Free-living genomes, in contrast to host-associated, tend to comprise (1) larger genomes, or the highest number of extra-chromosomal elements, (2) higher number of genomic islands and insertion sequence elements, and (3) a lower number of intact prophage regions. Regarding lifestyle adaptations, free-living genomes share genes linked to genetic exchange via T4SS, especially relevant for Paracoccus, known for their numerous extrachromosomal elements, enabling adaptation to dynamic environments. Conversely, host-associated genomes feature diverse genes involved in molecule transport, cell wall modification, attachment, stress protection, DNA repair, carbon, and nitrogen metabolism. Due to the vast number of adaptive genes, Paracoccus can quickly adapt to changing environmental conditions.

Heat-evolved algal symbionts enhance bleaching tolerance of adult corals without trade-off against growth

Ocean warming has caused coral mass bleaching and mortality worldwide and the persistence of symbiotic reef-building corals requires rapid acclimation or adaptation. Experimental evolution of the coral's microalgal symbionts followed by their introduction into coral is one potential method to enhance coral thermotolerance. Heat-evolved microalgal symbionts of the generalist species, Cladocopium proliferum (strain SS8), were exposed to elevated temperature (31°C) for ~10 years, and were introduced into four genotypes of chemically bleached adult fragments of the scleractinian coral, Galaxea fascicularis. Two of the four coral genotypes acquired SS8. The new symbionts persisted for the 5 months of the experiment and enhanced adult coral thermotolerance, compared with corals that were inoculated with the wild-type C. proliferum strain. Thermotolerance of SS8-corals was similar to that of coral fragments from the same colony hosting the homologous symbiont, Durusdinium sp., which is naturally heat tolerant. However, SS8-coral fragments exhibited faster growth and recovered cell density and photochemical efficiency more quickly following chemical bleaching and inoculation under ambient temperature relative to Durusdinium-corals. Mass spectrometry imaging suggests that algal pigments involved in photobiology and oxidative stress were the greatest contributors to the thermotolerance differences between coral hosting heat-evolved versus wild-type C. proliferum. These pigments may have increased photoprotection in the heat-evolved symbionts. This is the first laboratory study to show that thermotolerance of adult corals (G. fascicularis) can be enhanced via the uptake of exogenously supplied, heat-evolved symbionts, without a trade-off against growth under ambient temperature. Importantly, heat-evolved C. proliferum remained in the corals in moderate abundance 2 years after first inoculation, suggesting long-term stability of this novel symbiosis and potential long-term benefits to coral thermotolerance.

Fucoxanthin, a Functional Food Ingredient: Challenges in Bioavailability

PURPOSE OF REVIEW

Fucoxanthin is an orange-red xanthophyll carotenoid found in brown seaweeds and known for its many bioactive properties. In recent years, the bioactive properties of fucoxanthin have been widely explored, making it a compound of immense interest for various health applications like anti-cancer, anti-tumour, anti-diabetic and anti-obesity properties. However, the poor bioavailability and instability of fucoxanthin in the gastrointestinal tract have major limitations. Encapsulation is a promising approach to overcome these challenges by enclosing fucoxanthin in a protective layer, such as liposomes or nano-particles. Encapsulation can improve the stability of fucoxanthin by protecting it from exposure to heat, pH, illumination, gastric acids and enzymes that can accelerate its degradation.

RECENT FINDINGS

Studies have shown that lipid-based encapsulation systems such as liposomes or nano-structured lipid carriers may solubilise fucoxanthin and enhance its bioavailability (from 25 to 61.2%). In addition, encapsulation can also improve the solubility of hydrophobic fucoxanthin, which is important for its absorption and bioavailability. This review highlights the challenges involved in the absorption of fucoxanthin in the living system, role of micro- and nano-encapsulation of fucoxanthin and their potential to enhance intestinal absorption.

Microalgae-assisted green bioremediation of food-processing wastewater: A sustainable approach toward a circular economy concept

Wastewater disposal is a major environmental issue that pollutes water, causing eutrophication, habitat destruction, and economic impact. In Mexico, food-processing effluents pose a huge environmental threat due to their excessive nutrient content and their large volume discharged every year. Some of the most harmful residues are tequila vinasses, nejayote, and cheese whey. Each liter of tequila generates 13-15 L of vinasses, each kilogram of cheese produces approximately 9 kg of cheese whey, and each kilogram of nixtamalized maize results in the production of 2.5-3.3 L of nejayote. A promising strategy to reduce the contamination derived from wastewater is through microalgae-based wastewater treatment. Microalgae have a high adaptability to hostile environments and they can feed on the nutrients in the effluents to grow. Moreover, to increase the viability, profitability, and value of wastewater treatments, a microalgae biorefinery could be proposed. This review will focus on the circular bioeconomy scheme focused on the simultaneous food-processing wastewater treatment and its use to grow microalgae biomass to produce added-value compounds. This strategy allows for the revalorization of wastewater, decreases contamination of water sources, and produces valuable compounds that promote human health such as phycobiliproteins, carotenoids, omega-3 fatty acids, exopolysaccharides, mycosporine-like amino acids, and as a source of clean energy: biodiesel, biogas, and bioethanol.

An overview of food lipids toward food lipidomics

Increasing evidence regarding lipids' beneficial effects on human health has changed the common perception of consumers and dietary officials about the role(s) of food lipids in a healthy diet. However, lipids are a wide group of molecules with specific nutritional and bioactive properties. To understand their true nutritional and functional value, robust methods are needed for accurate identification and quantification. Specific analytical strategies are crucial to target specific classes, especially the ones present in trace amounts. Finding a unique and comprehensive methodology to cover the full lipidome of each foodstuff is still a challenge. This review presents an overview of the lipids nutritionally relevant in foods and new trends in food lipid analysis for each type/class of lipids. Food lipid classes are described following the LipidMaps classification, fatty acids, endocannabinoids, waxes, C8 compounds, glycerophospholipids, glycerolipids (i.e., glycolipids, betaine lipids, and triglycerides), sphingolipids, sterols, sercosterols (vitamin D), isoprenoids (i.e., carotenoids and retinoids (vitamin A)), quinones (i.e., coenzyme Q, vitamin K, and vitamin E), terpenes, oxidized lipids, and oxylipin are highlighted. The uniqueness of each food group: oil-, protein-, and starch-rich, as well as marine foods, fruits, and vegetables (water-rich) regarding its lipid composition, is included. The effect of cooking, food processing, and storage, in addition to the importance of lipidomics in food quality and authenticity, are also discussed. A critical review of challenges and future trends of the analytical approaches and computational methods in global food lipidomics as the basis to increase consumer awareness of the significant role of lipids in food quality and food security worldwide is presented.

Impact of hydrodynamics on community structure and metabolic production of marine biofouling formed in a highly energetic estuary

Biofouling is a specific lifestyle including both marine prokaryotic and eukaryotic communities. Hydrodynamics are poorly studied parameters affecting biofouling formation. This study aimed to investigate how water dynamics in the Etel Estuary (Northwest Atlantic coasts of France) influences the colonization of artificial substrates. Hydrodynamic conditions, mainly identified as shear stress, were characterized by measuring current velocity, turbulence intensity and energy using Acoustic Doppler Current Profiler (ADCP). One-month biofouling was analyzed by coupling metabarcoding (16S rRNA, 18S rRNA and COI genes), untargeted metabolomics (liquid chromatography coupled with high-resolution mass spectrometry, LC-HRMS) and characterization of the main biochemical components of the microbial exopolymeric matrix. A higher richness was observed for biofouling communities (prokaryotes and eukaryotes) exposed to the strongest currents. Ectopleura (Cnidaria) and its putative symbionts Endozoicomonas (Gammaproteobacteria) were dominant in the less dynamic conditions. Eukaryotes assemblages were specifically shaped by shear stress, leading to drastic changes in metabolite profiles. Under high hydrodynamic conditions, the exopolymeric matrix increased and was composed of 6 times more polysaccharides than proteins, these latter playing a crucial role in the adhesion and cohesion properties of biofilms. This original multidisciplinary approach demonstrated the importance of shear stress on both the structure of marine biofouling and the metabolic response of these complex communities.

A Narrative Review: The Effect and Importance of Carotenoids on Aging and Aging-Related Diseases

Aging is generally defined as a time-dependent functional decline that affects most living organisms. The positive increase in life expectancy has brought along aging-related diseases. Oxidative stress caused by the imbalance between pro-oxidants and antioxidants can be given as one of the causes of aging. At the same time, the increase in oxidative stress and reactive oxygen species (ROS) is main reason for the increase in aging-related diseases such as cardiovascular, neurodegenerative, liver, skin, and eye diseases and diabetes. Carotenoids, a natural compound, can be used to change the course of aging and aging-related diseases, thanks to their highly effective oxygen-quenching and ROS-scavenging properties. Therefore, in this narrative review, conducted using the PubMed, ScienceDirect, and Google Scholar databases and complying with the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines, the effects of carotenoids on aging and aging-related diseases were analyzed. Carotenoids are fat-soluble, highly unsaturated pigments that occur naturally in plants, fungi, algae, and photosynthetic bacteria. A large number of works have been conducted on carotenoids in relation to aging and aging-related diseases. Animal and human studies have found that carotenoids can significantly reduce obesity and fatty liver, lower blood sugar, and improve liver fibrosis in cirrhosis, as well as reduce the risk of cardiovascular disease and erythema formation, while also lowering glycated hemoglobin and fasting plasma glucose levels. Carotenoid supplementation may be effective in preventing and delaying aging and aging-related diseases, preventing and treating eye fatigue and dry eye disease, and improving macular function. These pigments can be used to stop, delay, or treat aging-related diseases due to their powerful antioxidant, restorative, anti-proliferative, anti-inflammatory, and anti-aging properties. As an increasingly aging population emerges globally, this review could provide an important prospective contribution to public health.

Next-Generation Organic Beauty Products Obtained from Algal Secondary Metabolites: A Sustainable Development in Cosmeceutical Industries

Algae lay over most of the earth's habitats, and it is said that there are more algal cells in water than there are stars in the sky. They are among the wealthiest marine resources that are to be deemed harmless, with hardly any deleterious consequences. Recently, they have received a lot of consideration to be used in cosmeceuticals. Cosmetics encompass synthetic concoctions that are extremely toxic to the environment. Due to their higher molecular size, synthetic cosmetic items induce undesirable side effects and inadequate absorption rates. Consequently, utilizing algae or their secondary metabolites in cosmetics has won multiple votes. Various secondary metabolites synthesized from algae are known to provide skin advantages, such as ultraviolet protection and reduction of skin flaccidity, rough texture, and wrinkles. The tangent drawn here using algae reduces the inorganic/organic chemicals used in the industry that are known to accumulate and affect other organisms and thus opens a pandora's box of ways to a less-polluted environment. The alga is indeed very intriguing. According to the reported studies, algal cells provide biosorption, bio-assimilation, biotransformation, and biodegradation, making them suitable for the eradication of chronic and harmful contaminants from the environment. Another rapid innovation is the product's sustainability. While presenting and marketing new algal products, cosmetics producers have greatly highlighted that they are eco-friendly. This review thus accentuates the significance of using algae and their secondary metabolites in cosmetics to produce extensive variety of products that include sunscreens, moisturizers, anti-aging creams, colorants, and hair care items and extensive insight on the possible remedial capacities of algae species against environmentally dangerous substances in the context of cosmetic chemicals.

MariClus: Your One-Stop Platform for Information on Marine Natural Products, Their Gene Clusters and Producing Organisms

BACKGROUND

The marine environment hosts the vast majority of living species and marine microbes that produce natural products with great potential in providing lead compounds for drug development. With over 70% of Earth's surface covered in water and the high interaction rate associated with liquid environments, this has resulted in many marine natural product discoveries. Our improved understanding of the biosynthesis of these molecules, encoded by gene clusters, along with increased genomic information will aid us in uncovering even more novel compounds.

RESULTS

We introduce MariClus (https://www.mariclus.com), an online user-friendly platform for mining and visualizing marine gene clusters. The first version contains information on clusters and the predicted molecules for over 500 marine-related prokaryotes. The user-friendly interface allows scientists to easily search by species, cluster type or molecule and visualize the information in table format or graphical representation.

CONCLUSIONS

This new online portal simplifies the exploration and comparison of gene clusters in marine species for scientists and assists in characterizing the bioactive molecules they produce. MariClus integrates data from public sources, like GenBank, MIBiG and PubChem, with genome mining results from antiSMASH. This allows users to access and analyze various aspects of marine natural product biosynthesis and diversity.

An unexpected hydratase synthesizes the green light-absorbing pigment fucoxanthin

The ketocarotenoid fucoxanthin and its derivatives can absorb blue-green light enriched in marine environments. Fucoxanthin is widely adopted by phytoplankton species as a main light-harvesting pigment, in contrast to land plants that primarily employ chlorophylls. Despite its supreme abundance in the oceans, the last steps of fucoxanthin biosynthesis have remained elusive. Here, we identified the carotenoid isomerase-like protein CRTISO5 as the diatom fucoxanthin synthase that is related to the carotenoid cis-trans isomerase CRTISO from land plants but harbors unexpected enzymatic activity. A crtiso5 knockout mutant in the model diatom Phaeodactylum tricornutum completely lacked fucoxanthin and accumulated the acetylenic carotenoid phaneroxanthin. Recombinant CRTISO5 converted phaneroxanthin into fucoxanthin in vitro by hydrating its carbon-carbon triple bond, instead of functioning as an isomerase. Molecular docking and mutational analyses revealed residues essential for this activity. Furthermore, a photophysiological characterization of the crtiso5 mutant revealed a major structural and functional role of fucoxanthin in photosynthetic pigment-protein complexes of diatoms. As CRTISO5 hydrates an internal alkyne physiologically, the enzyme has unique potential for biocatalytic applications. The discovery of CRTISO5 illustrates how neofunctionalization leads to major diversification events in evolution of photosynthetic mechanisms and the prominent brown coloration of most marine photosynthetic eukaryotes.

Sun protection and antibacterial activities of carotenoids from the soft coral Sinularia sp. symbiotic bacteria from Panjang Island, North Java Sea

Carotenoids have shown beneficial applications in cosmetology, pharmacology, and medicine. However, environmental stress in the marine environment can trigger the production of unique secondary metabolites, such as carotenoids. These compounds can also be sustainably produced by symbiotic bacteria. We hypothesized that the soft corals in tropical regions may produce diverse biological secondary metabolites, including carotenoids, both by the host organism and their bacterial symbiont. The unique carotenoids may provide promising biological activity such as antioxidant, UV photoprotector, and antibacterial activities. To this end, we isolated and characterized the carotenoids isolated from the bacterial symbiont of Sinularia sp., a soft coral from Panjang Island, North Java Sea, strain 19. PP.Sc.13. Bacterial identification was performed using DNA barcoding of the 16S rRNA region. Identification of carotenoids was carried out using a spectrophotometer, High-Performance Liquid Chromatography (HPLC), and attenuated total reflection fourier-transformed infrared (ATR-FTIR) spectroscopy. The antioxidant activity was estimated using the diphenylpicrylhydrazyl (DPPH) method, while the Sun Protection Factor (SPF) and % transmission of erythema and pigmentation were determined based on colorimetric methods. The antibacterial activity assay was carried out using the agar diffusion method against two multidrug-resistant bacteria. The bacterial symbiont was identified as Virgibacillus sp. and the carotenoids isolated from this symbiont exhibited significant antioxidant activity and extra sun protection effect, thus categorized as UVA sunblock. Furthermore, the isolated carotenoids exhibited antibacterial activities against Methicillin Resistant-Staphylococcus aureus (MRSA) and Multidrug-resistant (MDR) Escherichia coli. This study provides evidence of the carotenoids produced by the soft coral bacterial symbiont Virgibacillus sp., which may be used as an antioxidant, sun protection, and antibacterial agent. Further investigation of the de novo biological production of carotenoids by Virgibacillus sp. is warranted.

Sustainable production of bacterioruberin carotenoid and its derivatives from Arthrobacter agilis NP20 on whey-based medium: optimization and product characterization

Bacterioruberin and its rare glycosylated derivatives are produced by Arthrobacter agilis as an adaptation strategy to low temperature conditions. The high antioxidant properties of bacterioruberin held great promise for different future applications like the pharmaceutical and food industries. Microbial production of bacterioruberin via a cost-effective medium will help increase its commercial availability and industrial use. The presented study aims to optimize the production of the rare C50 carotenoid bacterioruberin and its derivatives from the psychotrophic bacteria Arthrobacter agilis NP20 strain on a whey-based medium as a cost effective and readily available nutritious substrate. The aim of the study is extended to assess the efficiency of whey treatment in terms of estimating total nitrogen content in treated and untreated whey samples. The significance of medium ingredients on process outcome was first tested individually; then the most promising factors were further optimized using Box Behnken design (BBD). The produced carotenoids were characterized using UV-visible spectroscopy, FTIR spectroscopy, HPLC-DAD chromatography and HPLC-APCI-MS spectrometry. The maximum pigment yield (5.13 mg/L) was achieved after a 72-h incubation period on a core medium composed of 96% sweet whey supplemented with 0.46% MgSO4 & 0.5% yeast extract and inoculated with 6% (v/v) of a 24 h pre-culture (109 CFU/mL). The cost of the formulated medium was 1.58 $/L compared with 30.1 $/L of Bacto marine broth medium. The extracted carotenoids were identified as bacterioruberin, bis-anhydrobacteriouberin, mono anhydrobacterioruberin, and glycosylated bacterioruberin. The presented work illustrates the possibility of producing bacterioruberin carotenoid from Arthrobacter agilis through a cost-effective and eco-friendly approach using cheese whey-based medium.

Seasonal Monitoring of Volatiles and Antioxidant Activity of Brown Alga Cladostephus spongiosus

Cladostephus spongiosus was harvested once a month during its growing season (from May to August) from the Adriatic Sea. Algal volatile organic compounds (VOCs) were obtained by headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD) and analysed by gas chromatography and mass spectrometry (GC-MS). The effects of air drying and growing season on VOCs were determined. Two different extraction methods (ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE)) were used to obtain ethanolic extracts of C. spongiosus. In addition, the seasonal antioxidant potential of the extracts was determined, and non-volatile compounds were identified from the most potent antioxidant extract. Aliphatic compounds (e.g., pentadecane) were predominantly found by HS-SPME/GC-MS. Hydrocarbons were more than twice as abundant in the dry samples (except in May). Aliphatic alcohols (e.g., hexan-1-ol, octan-1-ol, and oct-1-en-3-ol) were present in high percentages and were more abundant in the fresh samples. Hexanal, heptanal, nonanal, and tridecanal were also found. Aliphatic ketones (octan-3-one, 6-methylhept-5-en-2-one, and (E,Z)-octa-3,5-dien-2-one) were more abundant in the fresh samples. Benzene derivatives (e.g., benzyl alcohol and benzaldehyde) were dominant in the fresh samples from May and August. (E)-Verbenol and p-cymen-8-ol were the most abundant in dry samples in May. HD revealed aliphatic compounds (e.g., heptadecane, pentadecanal, (E)-heptadec-8-ene, (Z)-heptadec-3-ene), sesquiterpenes (germacrene D, epi-bicyclosesquiphellandrene, gleenol), diterpenes (phytol, pachydictyol A, (E)-geranyl geraniol, cembra-4,7,11,15-tetraen-3-ol), and others. Among them, terpenes were the most abundant (except for July). Seasonal variations in the antioxidant activity of the ethanolic extracts were evaluated via different assays. MAE extracts showed higher peroxyl radical inhibition activity from 55.1 to 74.2 µM TE (Trolox equivalents). The highest reducing activity (293.8 µM TE) was observed for the May sample. Therefore, the May MAE extract was analysed via high-performance liquid chromatography with high-resolution mass spectrometry and electrospray ionisation (UHPLC-ESI-HRMS). In total, 17 fatty acid derivatives, 9 pigments and derivatives, and 2 steroid derivatives were found. The highest content of pheophorbide a and fucoxanthin, as well as the presence of other pigment derivatives, could be related to the observed antioxidant activity.

Algal Carotenoids: Chemistry, Sources, and Application

Recently, the isolation and identification of various biologically active secondary metabolites from algae have been of scientific interest, with particular attention paid to carotenoids, widely distributed in various photosynthetic organisms, including algal species. Carotenoids are among the most important natural pigments, with many health-promoting effects. Since the number of scientific studies on the presence and profile of carotenoids in algae has increased exponentially along with the interest in their potential commercial applications, this review aimed to provide an overview of the current knowledge (from 2015) on carotenoids detected in different algal species (12 microalgae, 21 green algae, 26 brown algae, and 43 red algae) to facilitate the comparison of the results of different studies. In addition to the presence, content, and identification of total and individual carotenoids in various algae, the method of their extraction and the main extraction parameters were also highlighted.

The Microbiome of Things: Appliances, Machines, and Devices Hosting Artificial Niche-Adapted Microbial Communities

As it is the case with natural substrates, artificial surfaces of man-made devices are home to a myriad of microbial species. Artificial products are not necessarily characterized by human-associated microbiomes; instead, they can present original microbial populations shaped by specific environmental-often extreme-selection pressures. This review provides a detailed insight into the microbial ecology of a range of artificial devices, machines, and appliances, which we argue are specific microbial niches that do not necessarily fit in the "build environment" microbiome definition. Instead, we propose here the Microbiome of Things (MoT) concept analogous to the Internet of Things (IoT) because we believe it may be useful to shed light on human-made, but not necessarily human-related, unexplored microbial niches.

Thetidibacter halocola gen. nov., sp. nov., a novel member within the family Roseobacteraceae isolated from seawater

A Gram-staining-negative, strictly aerobic, dark beige-colored, rod-shaped, chemoorganoheterotrophic, and catalase- and oxidase-positive bacterium, designated as KMU-90^T, was isolated from coastal seawater in the Republic of Korea, and subjected to a polyphasic study. The novel isolate was able to grow at 0-6.0% NaCl concentrations (w/v), pH 6.5-9.5, and 4-45 °C. The 16S rRNA gene sequences-based phylogeny revealed that the novel marine isolate belongs to the family Roseobacteraceae of class Alphaproteobacteria and that it shared the greatest sequence similarity (97.3%) with Aestuariicoccus marinus NAP41^T. The novel strain could be distinguished phenotypically from related representatives of the family Roseobacteraceae. The major (> 10%) fatty acids of strain KMU-90^T were C_18:1 ω7c and C_18:1 ω7c 11-methyl and the only respiratory quinone was ubiquinone-10 (Q-10). Strain KMU-90^T contained phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, two unidentified aminolipids, an unidentified phospholipid, and three unidentified glycolipids as polar lipids. The assembled draft genome size of strain KMU-90^T was 4.84 Mbp with a DNA G + C content of 66.5%. The average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values between the genomes of strain KMU-90^T and its closely related representatives were 77.0-79.0%, 14.6-20.0%, and 60.0-69.9%, respectively. From the polyphasic taxonomic results obtained, the strain is considered to represent a novel genus and a new species of the family Roseobacteraceae, for which the name Thetidibacter halocola gen. nov., sp. nov. is proposed. The type species is T. halocola, with the type strain KMU-90^T (= KCCM 90287^T = NBRC 113375^T).

Role of secondary metabolites in distressed microalgae

Proficient photosynthetic microalgae/cyanobacteria produce a remarkable amount of various biomolecules. Secondary metabolites (SM) represent high value products for global biotrend application. Production improvement can be achieved by nutritional, environmental, and physiological stress as a first line tools for their stimulation. In recent decade, an increasing interest in algal stress biology and omics techniques have deepened knowledge in this area. However, deep understanding and connection of specific stress elucidator are missing. Hence, the present review summarizes recent evidence with an emphasis on the carotenoids, phenolic, and less-discussed compounds (glycerol, proline, mycosporins-like amino acids). Even when they are synthesized at very low concentrations, it highlights the need to expand knowledge in this area using genome-editing tools and omics approaches.

Carbon nanosheets to unravel the production of bioactive compounds from microalgae: A robust approach in drug discovery

The conglomeration of active pharmaceutical ingredients (APIs) has influenced the development of life-saving drugs. These APIs are customarily synthetic products, albeit with adverse side effects. Thus, to overcome the bottlenecks associated with synthetically derived APIs, the approach of photocatalytically obtaining bioactive compounds from natural ingredients has emerged. Amid the pool of photoactive nanomaterials, this short review emphasizes the intelligent strategy of exploiting photoactive carbon nanosheets to photocatalytically derive bioactive compounds from natural algal biomass to treat many acute or chronic medical conditions. Carbon nanosheets result in phototrophic harvesting of bioactive compounds from microalgae as a result of their being an effective biocatalyst that increases the rate of photosynthesis. To understand the clinical translation of bioactive compounds, the pharmacodynamics of algal bioactive compounds are highlighted to determine the practicality and feasibility of using this green approach for pharmaceutical drug discovery.

Natural Pigments Production and Their Application in Food, Health and Other Industries

In addition to fulfilling their function of giving color, many natural pigments are known as interesting bioactive compounds with potential health benefits. These compounds have various applications. In recent times, in the food industry, there has been a spread of natural pigment application in many fields, such as pharmacology and toxicology, in the textile and printing industry and in the dairy and fish industry, with almost all major natural pigment classes being used in at least one sector of the food industry. In this scenario, the cost-effective benefits for the industry will be welcome, but they will be obscured by the benefits for people. Obtaining easily usable, non-toxic, eco-sustainable, cheap and biodegradable pigments represents the future in which researchers should invest.

The Biochemistry and Effectiveness of Antioxidants in Food, Fruits, and Marine Algae

It is more effective to maintain good health than to regain it after losing it. This work focuses on the biochemical defense mechanisms against free radicals and their role in building and maintaining antioxidant shields, aiming to show how to balance, as much as possible, the situations in which we are exposed to free radicals. To achieve this aim, foods, fruits, and marine algae with a high antioxidant content should constitute the basis of nutritional elements, since natural products are known to have significantly greater assimilation efficiency. This review also gives the perspective in which the use of antioxidants can extend the life of food products, by protecting them from damage caused by oxidation as well as their use as food additives.

Effect of Astaxanthin on Tissue Transglutaminase and Cytoskeletal Protein Expression in Amyloid-Beta Stressed Olfactory Ensheathing Cells: Molecular and Delayed Luminescence Studies

Astaxanthin, a natural compound of Haematococcus pluvialis, possesses antioxidant, anti-inflammatory, anti-tumor and immunomodulatory activities. It also represents a potential therapeutic in Alzheimer’s disease (AD), that is related to oxidative stress and agglomeration of proteins such as amyloid-beta (Aβ). Aβ is a neurotoxic protein and a substrate of tissue transglutaminase (TG2), an ubiquitary protein involved in AD. Herein, the effect of astaxanthin pretreatment on olfactory ensheathing cells (OECs) exposed to Aβ(1–42) or by Aβ(25–35) or Aβ(35–25), and on TG2 expression were assessed. Vimentin, GFAP, nestin, cyclin D1 and caspase-3 were evaluated. ROS levels and the percentage of cell viability were also detected. In parallel, delayed luminescence (DL) was used to monitor mitochondrial status. ASTA reduced TG2, GFAP and vimentin overexpression, inhibiting cyclin D1 levels and apoptotic pathway activation which induced an increase in the nestin levels. In addition, significant changes in DL intensities were particularly observed in OECs exposed to Aβ toxic fragment (25–35), that completely disappear when OECs were pre-incubated in astaxantin. Therefore, we suggest that ASTA pre-treatment might represent an innovative mechanism to contrast TG2 overexpression in AD.

Sex-specific seasonal variations in the fatty acid and carotenoid composition of sea cucumber gonads and implications for aquaculture

Fatty acids and carotenoids are known to have roles in embryonic and larval development of sea cucumbers, but their changes in gonads during gametogenesis have not yet been studied. To improve our knowledge of the reproductive cycle of sea cucumbers in an aquaculture perspective, we collected 6-11 individuals of the species Holothuria (Panningothuria) forskali Delle Chiaje, 1823 approximately every 2 months from December 2019 to July 2021 east of the Glenan Islands (Brittany - France; 47.710°N, 3.948°W) at a depth of 8-12 m. Our results show that soon after spawning, sea cucumbers take advantage of an increased food availability in spring to rapidly and opportunistically accumulate nutrients in the form of lipids in their gonads (from May to July) and then slowly elongate, desaturate and probably rearrange fatty acids within lipid classes for the next reproductive season according to the specific requirements of both sexes. In contrast, acquisition of carotenoids occurs synchronously with gonads filling and/or through the reabsorption of spent tubules (T5), thus revealing little seasonal variations at the scale of the entire gonad in terms of relative abundance in both sexes. All results suggest that gonads are fully replenished with nutrients by October and that broodstock for induced reproduction could be captured at this moment and kept until the production of larvae is required. Maintaining broodstock for consecutive years would probably be a higher level challenge as the dynamics of tubule recruitment are not fully understood and seem to last for several years.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00227-023-04198-0.

Bacterial aerobic methane cycling by the marine sponge-associated microbiome

BACKGROUND

Methanotrophy by the sponge-hosted microbiome has been mainly reported in the ecological context of deep-sea hydrocarbon seep niches where methane is either produced geothermically or via anaerobic methanogenic archaea inhabiting the sulfate-depleted sediments. However, methane-oxidizing bacteria from the candidate phylum Binatota have recently been described and shown to be present in oxic shallow-water marine sponges, where sources of methane remain undescribed.

RESULTS

Here, using an integrative -omics approach, we provide evidence for sponge-hosted bacterial methane synthesis occurring in fully oxygenated shallow-water habitats. Specifically, we suggest methane generation occurs via at least two independent pathways involving methylamine and methylphosphonate transformations that, concomitantly to aerobic methane production, generate bioavailable nitrogen and phosphate, respectively. Methylphosphonate may be sourced from seawater continuously filtered by the sponge host. Methylamines may also be externally sourced or, alternatively, generated by a multi-step metabolic process where carnitine, derived from sponge cell debris, is transformed to methylamine by different sponge-hosted microbial lineages. Finally, methanotrophs specialized in pigment production, affiliated to the phylum Binatota, may provide a photoprotective function, closing a previously undescribed C₁-metabolic loop that involves both the sponge host and specific members of the associated microbial community.

CONCLUSION

Given the global distribution of this ancient animal lineage and their remarkable water filtration activity, sponge-hosted methane cycling may affect methane supersaturation in oxic coastal environments. Depending on the net balance between methane production and consumption, sponges may serve as marine sources or sinks of this potent greenhouse gas. Video Abstract.

Marine Natural Products as Innovative Cosmetic Ingredients

Over the course of the last 20 years, numerous studies have identified the benefits of an array of marine natural ingredients for cosmetic purposes, as they present unique characteristics not found in terrestrial organisms. Consequently, several marine-based ingredients and bioactive compounds are under development, used or considered for skin care and cosmetics. Despite the multitude of cosmetics based on marine sources, only a small proportion of their full potential has been exploited. Many cosmetic industries have turned their attention to the sea to obtain innovative marine-derived compounds for cosmetics, but further research is needed to determine and elucidate the benefits. This review gathers information on the main biological targets for cosmetic ingredients, different classes of marine natural products of interest for cosmetic applications, and the organisms from which such products can be sourced. Although organisms from different phyla present different and varied bioactivities, the algae phylum seems to be the most promising for cosmetic applications, presenting compounds of many classes. In fact, some of these compounds present higher bioactivities than their commercialized counterparts, demonstrating the potential presented by marine-derived compounds for cosmetic applications (i.e., Mycosporine-like amino acids and terpenoids’ antioxidant activity). This review also summarizes the major challenges and opportunities faced by marine-derived cosmetic ingredients to successfully reach the market. As a future perspective, we consider that fruitful cooperation among academics and cosmetic industries could lead to a more sustainable market through responsible sourcing of ingredients, implementing ecological manufacturing processes, and experimenting with inventive recycling and reuse programs.

Horizontal Gene Transfer and Fusion Spread Carotenogenesis Among Diverse Heterotrophic Protists

Thraustochytrids (phylum: Labyrinthulomycota) are nonphotosynthetic marine protists. Some thraustochytrids have crtIBY, a trifunctional fusion gene encoding a protein capable of β-carotene biosynthesis from geranylgeranyl pyrophosphate. Here we show that crtIBY is essential in, and encodes the sole pathway for, carotenoid biosynthesis in the thraustochytrid Aurantiochytrium limacinum ATCC MYA-1381. We explore the evolutionary origins of CrtIBY and discover that the closest related protein domains are present in a small but diverse group of other heterotrophic protists, including the apusomonad Thecamonas trahens and the dinoflagellates Oxyrrhis marina and Noctiluca scintillans. Each organism within this cluster also contains one or more β-carotene 15-15' oxygenase genes (blh and rpe65), suggesting that the acquisition of β-carotene biosynthesis genes may have been related to the production of retinal. Our findings support a novel origin of eukaryotic (apo)carotenoid biosynthesis by horizontal gene transfer from Actinobacteria, Bacteroidetes, and/or Archaea. This reveals a remarkable case of parallel evolution of eukaryotic (apo)carotenogenesis in divergent protistan lineages by repeated gene transfers.

Bacterial Pigments and Their Multifaceted Roles in Contemporary Biotechnology and Pharmacological Applications

Synthetic dyes and colourants have been the mainstay of the pigment industry for decades. Researchers are eager to find a more environment friendly and non-toxic substitute because these synthetic dyes have a negative impact on the environment and people’s health. Microbial pigments might be an alternative to synthetic pigments. Microbial pigments are categorized as secondary metabolites and are mainly produced due to impaired metabolism under stressful conditions. These pigments have vibrant shades and possess nutritional and therapeutic properties compared to synthetic pigment. Microbial pigments are now widely used within the pharmaceuticals, food, paints, and textile industries. The pharmaceutical industries currently use bacterial pigments as a medicine alternative for cancer and many other bacterial infections. Their growing popularity is a result of their low cost, biodegradable, non-carcinogenic, and environmentally beneficial attributes. This audit article has made an effort to take an in-depth look into the existing uses of bacterial pigments in the food and pharmaceutical industries and project their potential future applications.

Application of Marine Natural Products against Alzheimer's Disease: Past, Present and Future

Alzheimer's disease (AD), a neurodegenerative disease, is one of the most intractable illnesses which affects the elderly. Clinically manifested as various impairments in memory, language, cognition, visuospatial skills, executive function, etc., the symptoms gradually aggravated over time. The drugs currently used clinically can slow down the deterioration of AD and relieve symptoms but cannot completely cure them. The drugs are mainly acetylcholinesterase inhibitors (AChEI) and non-competitive N-methyl-D-aspartate receptor (NDMAR) antagonists. The pathogenesis of AD is inconclusive, but it is often associated with the expression of beta-amyloid. Abnormal deposition of amyloid and hyperphosphorylation of tau protein in the brain have been key targets for past, current, and future drug development for the disease. At present, researchers are paying more and more attention to excavate natural compounds which can be effective against Alzheimer's disease and other neurodegenerative pathologies. Marine natural products have been demonstrated to be the most prospective candidates of these compounds, and some have presented significant neuroprotection functions. Consequently, we intend to describe the potential effect of bioactive compounds derived from marine organisms, including polysaccharides, carotenoids, polyphenols, sterols and alkaloids as drug candidates, to further discover novel and efficacious drug compounds which are effective against AD.

Effects of diet containing astaxanthin on visual function in healthy individuals: a randomized, double-blind, placebo-controlled, parallel study

Visual display terminal work has increased rapidly in recent years. Loss of visual acuity is an unfortunate associated effect. Here, we performed a randomized, placebo-controlled study in 60 healthy adults. Participants received a diet containing astaxanthin (9 mg/day) or placebo for 6 weeks. Visual acuity, functional visual acuity, and pupil constriction rate were measured before and after visual display terminal work. In participants aged ≥40 years, corrected visual acuity of the dominant eye after visual display terminal work at 6 weeks after intake demonstrated a higher protective effect of astaxanthin in the astaxanthin group vs the control group (p<0.05). In participants aged <40 years, no significant difference was seen between the astaxanthin and control groups. Moreover, no significant difference was found in functional visual acuity and pupil constriction rate between the astaxanthin and control groups. These results suggest astaxanthin reduces oxidative stress caused by visual display terminal work. Age-related reduction in ciliary muscle strength is likely the main detractor of visual acuity. Correspondingly, astaxanthin reduced visual display terminal work-induced visual stress in the middle-aged and elderly. This study was registered in the UMIN-CTR database (UMIN000043089).

Protective effects of Scoparia dulcis L. extract on high glucose-induced injury in human retinal pigment epithelial cells

Diabetic retinopathy (DR) is a major cause of vision loss in diabetic patients. Hyperglycemia-induced oxidative stress and the accumulation of inflammatory factors result in blood-retinal barrier dysfunction and the pathogenesis of DR. Scoparia dulcis L. extract (SDE), a traditional Chinese medicine, has been recently recognized for its various pharmacological effects, including anti-diabetic, anti-hyperlipidemia, anti-inflammatory, and anti-oxidative activities. However, there is no relevant research on the protective effect of SDE in DR. In this study, we treated high glucose (50 mM) in human retinal epithelial cells (ARPE-19) with different concentrations of SDE and analyzed cell viability, apoptosis, and ROS production. Moreover, we analyzed the expression of Akt, Nrf2, catalase, and HO-1, which showed that SDE dose-dependently reduced ROS production and attenuated ARPE-19 cell apoptosis in a high-glucose environment. Briefly, we demonstrated that SDE exhibited an anti-oxidative and anti-inflammatory ability in protecting retinal cells from high-glucose (HG) treatment. Moreover, we also investigated the involvement of the Akt/Nrf2/HO-1 pathway in SDE-mediated protective effects. The results suggest SDE as a nutritional supplement that could benefit patients with DR.

Cryptochrome-mediated blue-light signal contributes to carotenoids biosynthesis in microalgae

Microalgae are considered as ideal cell factories for producing natural carotenoids which display favorable biological activities. As the most important abiotic factor, light not only provides energy for photosynthetic metabolism, but also regulates numerous biological processes. Blue light is the main wavelength of light that can travel through water. Previous studies have shown that blue light triggered carotenoid accumulation in several microalgae species, but the molecular mechanism remains unclear. Cryptochromes were blue-light-absorbing photoreceptors that have been found in all studied algal genomes. In this study, several different types of cryptochrome genes were cloned from Haematococcus pluvialis and Phaeodactylum tricornutum. Among them, cryptochrome genes HpCRY4 from H. pluvialis and PtCPF1 from P. tricornutum were upregulated under blue light treatment, in correlation with the increase of astaxanthin and fucoxanthin contents. Besides, heterologous expression and gene knockout was performed to verify the function of HpCRY4 and PtCPF1 in regulating carotenoid biosynthesis in microalgae. These results indicate that carotenoid biosynthesis in microalgae promoted by blue light was mediated by cryptochromes as photoreceptors.

Anti-Inflammatory Effects of Marine Bioactive Compounds and Their Potential as Functional Food Ingredients in the Prevention and Treatment of Neuroinflammatory Disorders

Functional foods include enhanced, enriched, fortified, or whole foods that impart health benefits beyond their nutritional value, particularly when consumed as part of a varied diet on a regular basis at effective levels. Marine sources can serve as the sources of various healthy foods and numerous functional food ingredients with biological effects can be derived from these sources. Microalgae, macroalgae, crustaceans, fungi, bacteria fish, and fish by-products are the most common marine sources that can provide many potential functional food ingredients including phenolic compounds, proteins and peptides, and polysaccharides. Neuroinflammation is closely linked with the initiation and progression of various neurodegenerative diseases, including Alzheimer's disease, Huntington's disease, and Parkinson's disease. Activation of astrocytes and microglia is a defense mechanism of the brain to counter damaged tissues and detrimental pathogens, wherein their chronic activation triggers neuroinflammation that can further exacerbate or induce neurodegeneration. Currently, available therapeutic agents only provide symptomatic relief from these disorders and no therapies are available to stop or slow down the advancement of neurodegeneration. Thereffore, natural compounds that can exert a protective effect against these disorders have therapeutic potential. Numerous chemical compounds, including bioactive peptides, fatty acids, pigments, alkaloids, and polysaccharides, have already been isolated from marine sources that show anti-inflammatory properties, which can be effective in the treatment and prevention of neuroinflammatory disorders. The anti-inflammatory potential of marine-derived compounds as functional food ingredients in the prevention and treatment of neurological disorders is covered in this review.

Astaxanthin Reduces the Severity of Intestinal Damage in a Neonatal Rat Model of Necrotizing Enterocolitis

OBJECTIVE

This study aimed to ascertain the effects of astaxanthin (ASX) in an experimental necrotizing enterocolitis (NEC) model using rat pups.

STUDY DESIGN

Forty-two pups born from five Wistar albino rats were randomly divided into three groups as the control group, NEC + placebo (saline), and NEC + ASX. Pups in the NEC + ASX group were given 100 mg/kg/day oral ASX from day 1 to day 4 of the study. Saline of 2 mL/kg was given to the NEC + placebo group. Histopathological, immunohistochemical (caspase-3), and biochemical evaluations including the total antioxidant status (TAS), total oxidant status (TOS), superoxide dismutase (SOD), glutathione (GSH), lipid hydroperoxide (LPO), 8-hydroxydeoxyguanosine (8-OHdG), advanced oxidation protein products (AOPP), myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and nuclear factor erythroid 2-related factor 2 (Nfr-2) activities were all performed.

RESULTS

A better survival rate and weight gain were demonstrated in the NEC + ASX group (p < 0.05). In the histopathological evaluation, the severity of intestinal damage was significantly reduced in the NEC + ASX group, as well as decreased apoptosis (enzyme-linked immunosorbent assay [ELISA] for caspase-3; p = 0.001). The biochemical analyses of intestinal tissue TOS, oxidative stress index (OSI; TOS/TAS), IL-1β, LPO, 8-OHdG, AOPP, caspase-3 (p < 0.001 for all), and TNF-α and MPO (p = 0.001 for both parameters) levels were lower in the NEC + ASX group than in the NEC + placebo group. Nrf-2, TAS, GSH, and SOD levels were higher in the NEC + ASX group than in the NEC + placebo group (p = 0.001, 0.001, <0.001, and 0.01, respectively).

CONCLUSION

ASX treatment has been shown to effectively reduce the severity of intestinal damage in NEC due to its antioxidant, anti-inflammatory, and antiapoptotic properties.

KEY POINTS

· NEC causes extremely high morbidity and mortality, as well as many complications.. · We investigated the effectiveness of ASX in the experimental NEC model created in rat pups.. · First study examining the effect of ASX on the experimental NEC rat model..

Lycopene: Sojourn from kitchen to an effective therapy in Alzheimer's disease

Reports on a significant positive correlation between consumption of carotenoid-rich food and prevention of Alzheimer's disease (AD) led to the investigation of carotenoids for the treatment and prevention of AD. More than 1100 types of carotenoids are found naturally, out of which only around 50 are absorbed and metabolized in human body. Lycopene is one of the most commonly ingested members of fat-soluble carotenoid family that gives vegetables and fruits their red, yellow, or orange color. Lycopene has established itself as a promising therapy for AD owing to its neuroprotective activities, including antioxidant, anti-inflammatory, and antiamyloidogenic properties. In this review, we highlight the various in vitro and preclinical studies demonstrating the neuroprotective effect of lycopene. Also, some epidemiological and interventional studies investigating the protective effect of lycopene in AD have been discussed. Diving deeper, we also discuss various significant mechanisms, through which lycopene exerts its remissive effects in AD. Finally, to overcome the issue of poor chemical stability and bioavailability of lycopene, some of the novel delivery systems developed for lycopene have also been briefly highlighted.

β-Cyclocitral: Emerging Bioactive Compound in Plants

β-cyclocitral (βCC), a main apocarotenoid of β-carotene, increases plants’ resistance against stresses. It has recently appeared as a novel bioactive composite in a variety of organisms from plants to animals. In plants, βCC marked as stress signals that accrue under adverse ecological conditions. βCC regulates nuclear gene expression through several signaling pathways, leading to stress tolerance. In this review, an attempt has been made to summarize the recent findings of the potential role of βCC. We emphasize the βCC biosynthesis, signaling, and involvement in the regulation of abiotic stresses. From this review, it is clear that discussing compound has great potential against abiotic stress tolerance and be used as photosynthetic rate enhancer. In conclusion, this review establishes a significant reference base for future research.