Mechanism of inhibition of melanoma by fucoxanthin simulated in vitro digestion products in cell models constructed using human malignant melanoma cells (A375) and keratinocytes (HaCaT).

Recently, the increasing incidence of malignant melanoma has become a major public health concern owing to its poor prognosis and impact on quality of life. Consuming foods with potent antitumor compounds can help prevent melanoma and maintain skin health. Fucoxanthin (FX), a naturally occurring carotenoid found in brown algae, possesses antitumor properties. However, its bioavailability, safety risks, and in vivo effects and mechanisms against melanoma remain unclear. This research focused on evaluating the safety and prospective antimelanoma impact of simulated gastrointestinal digestion products (FX-ID) on HaCaT and A375 cells.The results indicate that FX-ID exerts negative effects on mitochondria in A375 cells, increases Bax expression, releases Cytochrome C, and activates cleaved caspase-3, ultimately promoting apoptosis. Additionally, FX-ID influences the mitogen-activated protein kinase (MAPK) pathway by enhancing cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB) levels, consequently facilitating apoptosis and inflammation without significantly impacting HaCaT cells. These findings provide insight into inhibitory mechanism of FX-ID against melanoma, guiding the development of functional foods for prevention.

Functional ecological traits in young and adult thalli of canopy-forming brown macroalga Gongolaria barbata (Phaeophyta) from a transitional water system.

Background: Gongolaria barbata is a canopy-forming brown macroalga that thrives in the intertidal and subtidal habitats of the warm-temperate Mediterranean Sea, which is particularly exposed to environmental changes due to its peculiar geographical location and exposure to both global and local stressors. Testing whether this species is featured by specific functional, eco-physiological and biochemical traits allowing an efficient use of habitat resources and adaptation to environmental stress, and whether this potential might change with population growth, is essential for predicting the performance of the algae under different environmental abiotic variables (e.g., temperature, nutrient availability, light) and biotic interactions (such as grazing). Methods: Young (juveniles) and adult thalli of G. barbata were sampled in the winter season from the Venice Lagoon, Italy, featured by high environmental changes (temperature, salinity) and analyzed for thallus dry matter content (TDMC), photosynthetic activity, photosynthetic pigment and protein content, and antioxidant capacity to assess if thallus age may be considered a significant driver in determining the ecological responses of this species to environmental changes. Results: Our results showed that TDMC was higher in adults than juveniles. At the functional level, rapid light curves indicated an elevated photosynthetic efficiency in juveniles compared to adults highlighted by the higher quantum yield of PSII electron transport, electron transport rate, and Rubisco content observed in juveniles. On the contrary, adults exhibited a higher non-photochemical quenching and total pigment concentration. No difference in maximum PSII photochemical efficiency and D1 protein content between the two thalli groups was found. Along with better photosynthesis, juveniles also displayed a higher amount of total polyphenols, flavonoids, and tannins, and a stronger antioxidant capacity compared to adults. Conclusions: Our findings revealed significant differences in the eco-physiological characteristics of G. barbata at different growth stages. It was observed that young thalli, allocate more energy to photosynthesis and chemical defenses by increasing the production of antioxidant compounds, such as polyphenols, flavonoids, and tannins. With growth, thalli likely adopt a more conservative strategy, reducing photosynthesis and promoting structural biomass accumulation to mitigate the potential risks associated with prolonged exposure to environmental stressors, such as the wavy way. Although our study focused on a single phase of G. barbata life cycle under winter settings, it offers preliminary insights into this species eco-physiological traits and auto-ecology. Future research could explore the potential implications of these findings, evaluating the species' resilience to environmental changes at the population level.

Lipid Composition, Cytotoxic and Acetylcholinesterase Inhibition Effects of Two Brown Algae Species Lobophora tsengii and Lobophora australis.

In this paper, the lipid classes, compositions of the neutral lipids, phospholipids and fatty acids, acetylcholinesterase inhibition and cytotoxic activity of two brown algae Lobophora tsengii D. Tien & Z. Sun and Lobophora australis Z. Sun, F. C. Gurgel & H. Kawai have been investigated. The polar lipid class had the highest content in total lipid (TL) (43.47% in L. tsengii and 48.95% in L. australis). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were the main components in the phospholipids of two studied brown algae with contents varied from 32.27% to 52.33%. Total lipids were rich in PUFA (42.54% of total fatty acids for L. australis and 32.98% for L. tsengii), with EPA (11.46%, 14.30%) and AA (8.0%, 11.96%). L. tsengii methanol extract inhibited acetylcholinesterase (AChE) in in vitro assay with an IC50 value of 25.45 µg/mL. Both Lobophora methanol extracts display cytotoxic effects against four human cancer cell lines (KB, MCF7, HepG2 and A549) with IC50 in the range of 21.11-83.61 µg/mL. Especially, L. australis extract showed a strong cytotoxicity against KB cell lines with IC50 value of 21.11±0.39 µg/mL.

Various extracts of the brown seaweed Cystoseira barbata with different compositions exert biostimulant effects on seedling growth of wheat.

Worldwide, where the demand for novel and greener solutions for sustainable agricultural production is increasing, the use of eco-friendly products such as seaweed-derived biostimulants as pre-sowing treatment represent a promising and important approach for the future. Cystoseira barbata, a brown seaweed species abundant in the Mediterranean Region, was collected from the Marmara Sea and subjected to water, alkali, and acidic extractions, and the biostimulant activity of these extracts was tested on wheat (Triticum durum cv. Saricanak-98) using different rates through application to the seeds or germination medium (substrate) applications. The different extracts were characterized by mineral, total phenolic, free amino acid, mannitol, polysaccharide, antioxidant concentrations and hormone-like activity. The effects of the extracts on growth parameters, root morphology, esterase activity, and mineral nutrient concentrations of wheat seedlings were investigated. Our results suggest that the substrate application was more effective in enhancing the seedling performance compared to the seed treatment. High rates of seaweed extracts applied to substrates increased the shoot length and fresh weight of wheat seedlings by up to 20 and 25%, respectively. The substrate applications enhanced the root fresh weights of wheat seedlings by up to 25% when compared to control plants. Among the biostimulant extract applications, the water extract at the highest rate yielded the most promising results in terms of the measured parameters. Cystoseira barbata extracts with different compositions can be used as effective biostimulants to boost seedling growth. The local seaweed biomass affected by mucilage problems, has great potential as a bioeconomy resource and can contribute to sustainable practices for agriculture.

Structural characterization and immunomodulating assessment of ultra-purified water extracted fucoidans from Saccharina latissima, Alaria esculenta and Laminaria hyperborea.

Fucoidans, a group of high molecular weight polysaccharides derived mainly from brown algae, are characterized by their high fucose content, degree of sulfation (DS), and intra- and interspecific structural variation. Fucoidans are increasingly recognized due to various reported bioactivities, potentially beneficial for human health. To unlock their potential use within biomedical applications, a better understanding of their structure-functional relationship is needed. To achieve this, systematic bioactivity studies based on well-defined, pure fucoidans, and the establishment of standardized, satisfactory purification protocols are required. We performed a comprehensive compositional and structural characterization of crude and ultra-purified fucoidans from three kelps: Saccharina latissima (SL), Alaria esculenta (AE) and Laminaria hyperborea (LH). Further, the complement-inhibiting activity of the purified fucoidans was assessed in a human whole blood model. The purification process led to fucoidans with higher DS and fucose and lower concentrations of other monosaccharides. Fucoidans from SL and LH resembles homofucans, while AE is a heterofucan rich in galactose with comparably lower DS. Fucoidans from SL and LH showed complement-inhibiting activity in blood and blood plasma, while no inhibition was observed for AE under the same conditions. The results emphasize the importance of high DS and possibly fucose content for fucoidans' bioactive properties.

Brown Algae Ecklonia cava Extract Modulates Adipogenesis and Browning in 3T3-L1 Preadipocytes through HO-1/Nrf2 Signaling.

This study explores the anti-obesity effects of the ethyl acetate extract of Ecklonia cava (EC-ETAC) on 3T3-L1 preadipocytes, focusing on its impact on adipogenesis, lipolysis, and adipose browning via the HO-1/Nrf2 pathway. Western blot analysis revealed that EC-ETAC significantly inhibited adipogenic transcription factors (PPARγ, C/EBPα, SREBP-1) and lipogenesis-related proteins (FAS, LPL). Concurrently, EC-ETAC enhanced lipolytic markers (p-AMPK, p-HSL) and adipose browning-related proteins (UCP-1, PGC-1α), indicating its role in promoting lipolysis and adipose browning. The inhibition of HO-1 by zinc protoporphyrin (ZnPP) significantly reversed these effects, underscoring the critical role of HO-1 in mediating the anti-obesity properties of EC-ETAC. Additionally, fluorescence measurements and Oil Red O staining confirmed the reduction of lipid accumulation and oxidative stress upon EC-ETAC treatment. These findings suggest that EC-ETAC exerts its anti-obesity effects by modulating the HO-1/Nrf2 pathway, which is crucial for regulating adipogenesis, lipolysis, and adipose browning. This study highlights the potential of EC-ETAC as a natural therapeutic agent for obesity management and supports further research into its clinical applications. By targeting the HO-1/Nrf2 pathway, EC-ETAC could offer a novel approach to enhancing energy expenditure and reducing fat mass, thereby improving metabolic health.

Evaluation of Antioxidant Activity of Residue from Bioethanol Production Using Seaweed Biomass.

This study explores the potential of producing bioethanol from seaweed biomass and reusing the residues as antioxidant compounds. Various types of seaweed, including red (Gelidium amansii, Gloiopeltis furcata, Pyropia tenera), brown (Saccharina japonica, Undaria pinnatifida, Ascophyllum nodosum), and green species (Ulva intestinalis, Ulva prolifera, Codium fragile), were pretreated with dilute acid and enzymes and subsequently processed to produce bioethanol with Saccharomyces cerevisiae BY4741. Ethanol production followed the utilization of sugars, resulting in the highest yields from red algae > brown algae > green algae due to their high carbohydrate content. The residual biomass was extracted with water, ethanol, or methanol to evaluate its antioxidant activity. Among the nine seaweeds, the A. nodosum bioethanol residue extract (BRE) showed the highest antioxidant activity regarding the 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity, ferric reducing antioxidant power (FRAP), and reactive oxygen species (ROS) inhibition of H2O2-treated RAW 264.7 cells. These by-products can be valorized, contributing to a more sustainable and economically viable biorefinery process. This dual approach not only enhances the utilization of marine resources but also supports the development of high-value bioproducts.

Phototoxicity of the Ethanolic Extract of Skeletonema marinoi for the Dermocosmetic Improvement of Acne.

Acne is one of the most common dermatological conditions, peaking during adolescence and early adulthood, affecting about 85% of individuals aged 12-24. Although often associated with teenage years, acne can occur at any age, impacting over 25% of women and 12% of men in their forties. Treatment strategies vary depending on the severity, including the use of topical gels or creams containing benzoyl peroxide and retinoids, antibiotics, and systemic or topical isotretinoin. However, these treatments can cause irritation, allergies, and other toxic side effects. Currently, there is no natural-based alternative for antibacterial photodynamic therapy targeting acne using marine drugs or extracts. Through a bioguided screening approach, we identified the ethanol extract of Skeletonema marinoi as highly phototoxic against three bacterial species associated with acne-Cutibacterium acnes, Staphylococcus aureus, and Staphylococcus epidermidis. This extract exhibited phototoxicity in planktonic bacteria under white and red light, disrupted bacterial biofilms, reduced sebum production but also showed phototoxicity in keratinocytes, highlighting the importance of the specific targeting of treatment areas. Further investigations, including fractionation and high-resolution structural analysis, linked the observed phototoxicity to a high concentration of pheophorbide a in the extract. Given its notable in vitro efficacy, this extract holds promising potential for clinical evaluation to manage mild acne. This discovery paves the way for further exploration of Skeletonema pigment extracts, extending their potential applications beyond acne phototherapy to include dermocosmetics, veterinary medicine, and other phototherapy uses.

Antibacterial and Immunosuppressive Effects of a Novel Marine Brown Alga-Derived Ester in Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic skin condition that is characterized by dysregulated immune responses and a heightened risk of Staphylococcus aureus infections, necessitating the advancement of innovative therapeutic methods. This study explored the potential of (6Z,9Z,12Z,15Z)-(2R,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl octadeca-6,9,12,15-tetraenoate (HSN-S1), a compound derived from the marine alga Hizikia fusiformis, which shows anti-inflammatory, antimicrobial, and immunomodulatory properties. HSN-S1 was isolated and characterized using advanced chromatographic and spectroscopic methods. Its efficacy was evaluated via in vitro assays with keratinocytes, macrophages, and T cells to assess cytokine suppression and its immunomodulatory effects; its antibacterial activity against S. aureus was quantified. The in vivo effectiveness was validated using a 2,4-dinitrochlorobenzene-induced AD mouse model that focused on skin pathology and cytokine modulation. HSN-S1 significantly reduced pro-inflammatory cytokine secretion, altered T-helper cell cytokine profiles, and showed strong antibacterial activity against S. aureus. In vivo, HSN-S1 alleviated AD-like symptoms in mice and reduced skin inflammation, transepidermal water loss, serum immunoglobulin-E levels, and Th2/Th17 cytokine outputs. These findings suggest HSN-S1 to be a promising marine-derived candidate for AD treatment, as it offers a dual-target approach that could overcome the limitations of existing therapies, hence warranting further clinical investigation.

In Vitro Anti-HIV-1 Activity of Fucoidans from Brown Algae.

Due to the developing resistance and intolerance to antiretroviral drugs, there is an urgent demand for alternative agents that can suppress the viral load in people living with human immunodeficiency virus (HIV). Recently, there has been increased interest in agents of marine origin such as, in particular, fucoidans to suppress HIV replication. In the present study, the anti-HIV-1 activity of fucoidans from the brown algae Alaria marginata, Alaria ochotensis, Laminaria longipes, Saccharina cichorioides, Saccharina gurianovae, and Tauya basicrassa was studied in vitro. The studied compounds were found to be able to inhibit HIV-1 replication at different stages of the virus life cycle. Herewith, all fucoidans exhibited significant antiviral activity by affecting the early stages of the virus-cell interaction. The fucoidan from Saccharina cichorioides showed the highest virus-inhibitory activity by blocking the virus' attachment to and entry into the host's cell, with a selectivity index (SI) > 160.

Psychrosphaera algicola sp. nov. and Paraglaciecola algarum sp. nov., and reclassification of Pseudoalteromonas elyakovii, Pseudoalteromonas flavipulchra, and Pseudoalteromonas profundi as later heterotypic synonyms of P. distincta, P. maricaloris, and P. gelatinilytica.

Two Gram-negative, obligately aerobic, rod-shaped bacteria, strains G1-22T and G1-23T, were isolated from the phycosphere of a marine brown alga. Both strains exhibited catalase- and oxidase-positive activities. Strain G1-22T displayed optimal growth at 25 °C, pH 8.0, and 2.0-3.0% (w/v) NaCl, while strain G1-23T exhibited optimal growth at 25 °C, pH 8.0, and 4.0% NaCl. Ubiquinone-8 was identified as the sole isoprenoid quinone in both strains. As major fatty acids (> 5%), strain G1-22T contained C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C12 : 1 3-OH, and C10 : 0 3-OH, while strain G1-23T contained C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), and C14 : 0. Phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol were major polar lipids in both strains. Strains G1-22T and G1-23T had DNA G+C contents of 40.2 and 38.9 mol%, respectively. Phylogenetic analyses based on 16S rRNA and genome sequences revealed that strains G1-22T and G1-23T formed distinct phylogenetic lineages within the genera Psychrosphaera and Paraglaciecola, respectively. Strain G1-22T showed closest relatedness to Psychrosphaera ytuae MTZ26T with 97.8% 16S rRNA gene sequence similarity, 70.2% average nucleotide identity (ANI), and a 21.5% digital DNA-DNA hybridization (dDDH) value, while strain G1-23T was most closely related to Paraglaciecola aquimarina KCTC 32108T with 95.6% 16S rRNA gene sequence similarity, 74.6% ANI, and a 20.1% dDDH value. Based on phenotypic and molecular characteristics, strains G1-22T and G1-23T are proposed to represent two novel species, namely Psychrosphaera algicola sp. nov. (type strain G1-22T=KACC 22486T=JCM 34971T) and Paraglaciecola algarum sp. nov. (type strain G1-23T=KACC 22490T=JCM 34972T), respectively. Additionally, based on the comparison of whole genome sequences, it is proposed that Pseudoalteromonas elyakovii, Pseudoalteromonas flavipulchra, and Pseudoalteromonas profundi are reclassified as later heterotypic synonyms of Pseudoalteromonas distincta, Pseudoalteromonas maricaloris, and Pseudoalteromonas gelatinilytica, respectively.

Anticancer efficacy of magnetite nanoparticles synthesized using aqueous extract of brown seaweed Rosenvingea intricata, South Andaman, India.

Cancer is a global issue and hence various efforts are being made. Iron oxide is considered a significant biochemical agent in the biomedical arena for cancer treatment. Marine macroalgae-mediated iron oxides especially, magnetite (Fe3O4) nanoparticles (NPs) are a prospective alternative to diagnose and treat cancer owing to their fluorescent and magnetic properties. We intend to appraise the usability of the aqueous extract of Rosenvingea intricata (R. intricata) in Fe3O4 NPs synthesis and to study their cytotoxic effects against human hepatocarcinoma (Hep3B) and pancreatic (PANC1) cancer cells. In the present study, R. intricata were collected from the coastal region of South Andaman, India. Aqueous extracts of R. intricata were utilized to synthesize Fe3O4 NPs via the co-precipitation method. Phycosynthesized Fe3O4 NPs exhibited wide peak at 400-600 nm from ultraviolet-visible diffused reflectance spectroscopic analysis which validated the formation of NPs. Band edge emission peak at 660 nm in fluorescent spectra confirmed the quantum confinement in Fe3O4 NPs. Fourier transform infrared spectroscopy confirmed the role of R. intricata as a capping and reducing agent with functional groups such as O-H, C-H, C=O, N=O, C=C, C-O, C-N, and C-S arising from amino acids, polysaccharides, aliphatic hydrocarbons, esters, amides, lignins, alkanes, aliphatic amines, and sulfates. Physicochemical properties such as crystallite size (14.36 nm), hydrodynamic size (84.6 nm), irregular morphology, elemental composition, particle size (125 nm), crystallinity, and saturation magnetization (0.90007 emu/g) were obtained from x-ray diffractometer, dynamic light scattering, scanning electron microscopy, energy dispersive x-ray spectrometer, high-resolution transmission electron microscopy, selected area electron diffraction and vibrating sample magnetometer techniques, respectively. The cell viability showed dose-dependent cytotoxic effects and enhanced the apoptosis against Hep3B and PANC1 cancer cells. R. intricata extract capped Fe3O4 NPs could be the most appropriate and effective nanomaterial for cancer treatment and management.

Polysaccharides induce deep-sea Lentisphaerae strains to release chronic bacteriophages.

Viruses are ubiquitous in nature and play key roles in various ecosystems. Notably, some viruses (e.g. bacteriophage) exhibit alternative life cycles, such as chronic infections without cell lysis. However, the impact of chronic infections and their interactions with the host organisms remains largely unknown. Here, we found for the first time that polysaccharides induced the production of multiple temperate phages infecting two deep-sea Lentisphaerae strains (WC36 and zth2). Through physiological assays, genomic analysis, and transcriptomics assays, we found these bacteriophages were released via a chronic style without host cell lysis, which might reprogram host polysaccharide metabolism through the potential auxiliary metabolic genes. The findings presented here, together with recent discoveries made on the reprogramming of host energy-generating metabolisms by chronic bacteriophages, shed light on the poorly explored marine virus-host interaction and bring us closer to understanding the potential role of chronic viruses in marine ecosystems.

Organellar Genomes of Sargassum hemiphyllum var. chinense Provide Insight into the Characteristics of Phaeophyceae.

Sargassum hemiphyllum var. chinense, a prevalent seaweed along the Chinese coast, has economic and ecological significance. However, systematic positions within Sargassum and among the three orders of Phaeophyceae, Fucales, Ectocarpales, and Laminariales are in debate. Here, we reported the organellar genomes of S. hemiphyllum var. chinense (34,686-bp mitogenome with 65 genes and 124,323 bp plastome with 173 genes) and the investigation of comparative genomics and systematics of 37 mitogenomes and 22 plastomes of Fucales (including S. hemiphyllum var. chinense), Ectocarpales, and Laminariales in Phaeophyceae. Whole genome collinearity analysis showed gene number, type, and arrangement were consistent in organellar genomes of Sargassum with 360 SNP loci identified as S. hemiphyllum var. chinense and two genes (rps7 and cox2) identified as intrageneric classifications of Sargassum. Comparative genomics of the three orders of Phaeophyceae exhibited the same content and different types (petL was only found in plastomes of the order Fucales and Ectocarpales) and arrangements (most plastomes were rearranged, but trnA and trnD in the mitogenome represented different orders) in genes. We quantified the frequency of RNA-editing (canonical C-to-U) in both organellar genomes; the proportion of edited sites corresponded to 0.02% of the plastome and 0.23% of the mitogenome (in reference to the total genome) of S. hemiphyllum var. chinense. The repetition ratio of Fucales was relatively low, with scattered and tandem repeats (nine tandem repeats of 14-24 bp) dominating, while most protein-coding genes underwent negative selection (Ka/Ks < 1). Collectively, these findings provide valuable insights to guide future species identification and evolutionary status of three important Phaeophyceae order species.

Optimizing the fucoidan extraction using Box-Behnken Design and its potential bioactivity.

Fucoidan is a sulfated polysaccharide that occurs naturally in the cell wall of brown seaweeds and has substantial biological efficacy. Optimizing the extraction of fucoidan from different brown seaweeds was the primary goal of this research. The optimization of fucoidan extraction was applied on the brown macroalga Turbinaria turbinata using a Box-Behnken Design (BBD) to inspect the impacts of different pH (3, 5, 7), temperature (70, 80, 90 °C) and extraction duration (60, 120, 180 min) on both the yield and sulfate content of fucoidan. The optimized parameters recorded to maximize the fucoidan yield and its sulfate content were a pH of 3.44 and a temperature of 82.26 °C for 60 min. The optimal conditions obtained from BBD were used for fucoidan extraction from T. turbinata, Sargassum cinereum, Padina pavonica, and Dictyota dichotoma. The highest average of fucoidan yield was derived from P. pavonica (40.76 ± 4.04 % DW). FTIR, 1H NMR, and HPLC were used to characterize extracted fucoidan. The extracted fucoidan's Physical characteristics, biochemical composition, antioxidant potential, antitumor effect against breast cancer cells (MCF-7), and antimicrobial and anticoagulant activity were assessed. The extracted fucoidan from D. dichotoma, followed by that extracted from S. cinereum, which had the highest sulphate content, depicted the highest antioxidant, anticancer, and anticoagulant activities. Fucoidan has demonstrated a strong antimicrobial action against some pathogenic microorganisms; Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, and Candida albicans. The anticoagulant properties of fucoidan from D. dichotoma were stronger than those of fucoidan from S. cinereum, T. turbinata, and P. pavonica due to its higher sulphate content. These findings could be used for various biomedical applications to improve the pharmaceutical industry.

Chemical composition and growth responses of brown, green, and red macroalgae to pollution in the Russian black sea.

Macroalgae have long served as bioindicators of pollution in coastal marine environments. However, conventional pollution assessment methods often take a compartmentalized approach, either focusing on macrophyte biological parameters or independently analyzing heavy metal and oil product bioaccumulation within them. This study establishes connections between: (1) the characteristics of chemical pollution in brown, green, and red macroalgae, (2) organic pollution in the nutrient medium, and (3) the resulting changes in phytocenosis composition and macrophyte morphological characteristics. The research was conducted in the coastal zone near the Sochi River mouth on the Black Sea coast of Russia, encompassing the urban center of the Sochi metropolitan area. Inductively Coupled Plasma (ICP) analysis quantified the accumulation levels of 60 chemical elements within macrophyte algae. The novel aspect of this study is the development of a quantitative metric for assessing the overall chemical pollution impacting the ecologically crucial macroalgae Cystoseira. This systematic approach represents a significant advancement in the comprehensive evaluation and management of coastal water quality. The study identified two contrasting accumulation patterns: (1) pollution-tolerant annual algae exhibited an exclusion mechanism for chemical elements, while (2) Cystoseira displayed a non-exclusion accumulation pattern, potentially explaining its absence in the most heavily polluted zone. This approach paves the way for establishing a standardized scale for algal chemical pollution, reflecting a range from permissible to highly hazardous levels in seawater. This will enable rapid acquisition of both qualitative and quantitative pollution data, streamline monitoring efforts, and expedite the implementation of control measures.

Optimization and characterization of brown seaweed alginate for antioxidant, anticancer, antimicrobial, and antiviral properties.

Alginate is a natural polysaccharide obtained from brown seaweeds and having advantageous health usefulness, was employed extensively in nutraceutical sectors and the pharmaceutical industry. This research was devoted for optimization of alginate extraction from different brown seaweeds. A Box-Behnken Design (BBD) was used for the optimization of alginate extraction from Padina pavonica by analyzing the influence of temperature (30, 40, and 50 °C), time (60, 120, and 180 min), and alkaline concentration (1 %, 2 %, and 3 %) on extraction yield and uronic acid content. The optimal conditions recorded to maximize the alginate yield and its uronic content were an alkali concentration of 2.5 % and a temperature of 39.95 °C for 102.5 min. The optimized parameters achieved from BBD were used to compare alginate extraction from P. pavonica, Sargassum cinereum, Turbinaria turbinata, and Dictyota dichotoma. FTIR, 1H NMR, and HPLC were used to characterize the extracted alginate. The bioactivity of alginate against free radicals, breast cancer cells (MCF-7), some pathogenic microbes, and SARS-CoV-2 viruses was tested. Under the optimized conditions, alginate was extracted from P. pavonica at a rate of 21.13 ± 2.47 % DW, S. cinereum at 24.08 ± 0.33 % DW g/L, T. turbinata at 17.47 ± 0.26 % DW, and D. dichotoma at a rate of 19.57 ± 3.60 % DW. The alginate extracted from D. dichotoma showed the highest antioxidant, anticancer, and antiviral activity.

MUM, a maternal unknown message, inhibits early establishment of the medio-lateral axis in the embryo of the kelp Saccharina latissima.

Brown algae are multicellular photosynthetic organisms that have evolved independently of plants and other algae. Here, we have studied the determinism of body axis formation in the kelp Saccharina latissima. After microdissection of the embryo, we show that the stalk, an empty cell that retains the embryo on the maternal tissue, represses longitudinal cell divisions in the early embryo, thereby reinforcing the establishment of the initial apico-basal axis. In addition, it promotes cell growth and controls cell shape and arrangement in the flat oblong embryo composed of cells aligned in rows and columns. Although the stalk persists for several weeks until the embryo reaches at least 500 cells, proper embryogenesis requires connection to maternal tissue only during the first 4 days after fertilisation, i.e. before the embryo reaches the 8-cell stage. Transplantation experiments indicate that the maternal signal is not diffused in seawater, but requires contact between the embryo and the maternal tissue. This first global quantitative study of brown algal embryogenesis highlights the role of MUM, an unknown maternal message, in the control of growth axes and tissue patterning in kelp embryos.

Unraveling the neutral and polar lipidome of Nordic brown macroalgae: A sustainable source of functional lipids.

Brown macroalgae represent a sustainable and abundant source of lipids with acknowledged functional and health benefits. Nonetheless, macroalgae lipidome has been poorly unraveled due to lipids complex structural and chemical diversity. In this study, a comprehensive lipidomic analysis was performed in four macroalgae: Saccharina latissima, Fucus vesiculosus, Fucus serratus and the invasive Sargassum muticum, using HILIC-C30RP-HRMS. Neutral lipids (tri-, di-glycerides) comprised 72-82% of total lipids (TL) with a highly unsaturation profile (27-49% depending on species). The polar lipidome comprised glycolipids, phospholipids, betaine lipids and sphingolipids with varied content among macroalgae. S. latissima displayed the greatest level of glycolipids (23% of TL), by contrast with the dominance of long-chain polyunsaturated betaine lipids (10-18% of TL) in the other species, particularly in S. muticum. Phospholipids and sphingolipids were detected in low abundance (<1.7% of TL). This study elevated the potential of brown macroalgae as an emerging reservoir of bioactive lipids with nutritional relevance.

Sulfur release behavior and sulfur fixation mechanism during biomass microwave co-pyrolysis of Ascophyllum and rice straw.

Co-pyrolysis with low-sulfur biomass is expected to improve the yield and quality of bio-fuels, without the usage of calcium-based desulfurizer. Sulfur transformation during microwave fluidized-bed co-pyrolysis between terrestrial and marine biomass (Ascophyllum, AS; Rice straw, RS) was investigated. Sulfur release was promoted during biomass co-pyrolysis, but it was inhibited during pyrolysis between AS and low-sulfur char. Thermal cracking of biomass was promoted during co-pyrolysis between biomass, accelerating the combination of H atoms and -SH radicals. Introduction of low-sulfur bio-char (CA) inhibited the generation of bio-char and the release of sulfur. Released sulfur was captured by -OH/C = C functional groups on bio-char through dehydration reactions/addition reactions, forming mercaptan in bio-char. Furthermore, introduction of microwave and bio-char promoted the cyclization and aromatization reaction, converting mercaptan to thiophene and improving the thermal stability of solid sulfur, and thus increasing in-situ sulfur fixation rate.