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Sargassum (Sargassaceae) is widely distributed globally and plays an important role in regulating climate change, but the landscape of genomes and transcripts is less known. High‐quality nucleic acids are the basis for molecular biology experiments such as high‐throughput sequencing. Although extensive studies have documented methods of RNA extraction, these methods are not very applicable to Sargassum, which contains high levels of polysaccharides and polyphenols. To find a suitable method to improve the quality of RNA extracted, we compared and modified several popular RNA extraction methods and screened one practical method with three specific Sargassum spp. The results showed that three CTAB methods (denoted as Methods 1, 2, and 3) and the RNAprep Pure Plant Kit (denoted as Method 4) could, with slight modifications, effectively isolate RNA from Sargassum species, except for Method 4 used with S. fusiforme. By performing further screening, we determined Method 4 was the best choice for S. hemiphyllum and S. henslowianum, as revealed by RNA yields, RNA Integrity Number (RIN), extraction time, and unigene mapped ratio. For S. fusiforme, Methods 1, 2, and 3 showed no obvious differences among the yields, quality, or time to perform. In addition, one other method was tested, but we found the quality of the RNA extracted by TRIzol reagent methods (denoted as Method 5) performed the worst when compared with the above four methods. Therefore, our study provides four suitable methods for RNA extraction in Sargassum and is essential for future genetic exploration of Sargassum. [ABSTRACT FROM AUTHOR]

Seaweed is of importance to the environment due to properties such as its CO2 sequestration capability. On the other hand, plastic is a versatile material important to society. Unfortunately, the abundance of both plastics and seaweed represents a challenge due to the need of adequate waste management. At first, algae and plastics might not appear suitable for energy recovery; however, with co-gasification, the results are promising. This work presents a model to simulate the co-gasification of Chlorella vulgaris, Sargassum fluitans, and Sargassum natans with plastics. The effect of the gasification temperature (650–850 °C), equivalence ratio (0.25–0.45), and plastics/biomass ratio (0.0–1.0) on the produced gas's lower heating value, tar concentration, and composition is assessed. Moreover, the environmental performance of using plastic to enhance the syngas produced from the co-gasification with sargassum is assessed using the life cycle assessment methodology. The results indicate that the lower heating value increases with the temperature and plastics/biomass ratio. Moreover, tar increases with the quantity of plastics, varying between 20 and 50 g/Nm3. Finally, adding plastics to algae during gasification reduces the variability in the syngas composition, simplifying the post-processing stage. With respect to environmental performance, gasification has an impact similar to those of pyrolysis and recycling, but the performance could improve with sufficient research and development. [ABSTRACT FROM AUTHOR]

Marine mesograzers use macroalgae as food and habitat and may have strong top‐down effects on plants and macroalgae. Sympatric mesograzer species often differ regarding host use and feeding behavior, which may lead to distinct impacts by these consumers on primary producers. The amphipods Hyale niger and Ampithoe marcuzzii are mesograzers abundant that co‐occur in Brazilian waters and, although they use several macroalgae as habitat, it is unknown how much the food value of these hosts explains the host use pattern by the two mesograzers. Herein, we investigated the abundance and feeding behavior of the sympatric amphipods H. niger and A. marcuzzii. For that, their abundance on the macroalgal hosts Sargassum filipendula, Padina gymnospora, and Dichotomaria marginata was evaluated seasonally in a rocky shore at Fortaleza Beach, state of São Paulo, Brazil. Also, multiple‐choice and no‐choice feeding experiments were carried out at laboratory to evaluate the feeding behavior of these mesograzers. The abundance of H. niger was similar among the three macroalgal hosts (except during winter), while A. marcuzzii was more abundant on Dichotomaria and Padina than Sargassum in all seasons. Moreover, H. niger consumed more Padina than Dichotomaria and Sargassum in both feeding experiments. In turn, A. marcuzzii preferred to feed on Padina when it had a choice and consumed the three macroalgal hosts at similar levels in the no‐choice feeding experiment. Overall, H. niger and A. marcuzzii differ from each other regarding their feeding behavior and host use pattern. In particular, the food value of macroalgae seems to partially explain the host use by A. marcuzzi, but not by H. niger. The differences between H. niger and A. marcuzzii may result in varying impacts on primary producers. [ABSTRACT FROM AUTHOR]

• Marine brown agae (Sargassum wightii) has revealed its potential effects. • Palmitic acid scored good docking values against α-amylase and α-glucosidase. • ADME score of palmitic acid has recorded good activity. • Non-target toxicity assays proved that potential pharmaceutical effects. Jeopardized glucose hemostasis leads to cronic metaboic disorder like Diabetes mellitus and it is predicted to occur in ∼700 million people in the coming 20 years. Our study aims to isolate Palmitic acid (C 16 H 32 O 3), 9-Hydroxyhexadecanoic acid metabolite from Sargassum wightii to inhibit alpha-amylase and alpha-glucosidase to reduce postprandial hyperglycemia and decline the risk of diabetes. High docking score of palmitic acid with both α-amylase and α-glucosidase is observed in in-silico molecular docking analysis, in comparison to commercially available drug acarbose. The three hydrogen bond in palmitic acid interacts with the important amino acids like Arg195, Lys200 and Asp300 in Glide XP docking mode for alpha-amylase. For α-glucosidase, quantum-polarized ligand docking (QPLD) was used with similar three hydrogen bond interactions. Both docking studies showed significant binding interaction of palmitic acid with α-amylase (− 5.66 and −5.14 (Kcal/mol)) and with α-glucosidase (−4.52 and −3.51(Kcal/mol)) with respect to the standard, acarbose docking score. The bioactive palmitic acid isolated from the brown alga, Sargassum wightii is already seen to inhibit digestive enzyme with non-target property in Artemia nauplii and zebra fish embryos. Further studies are required to investigate its role in in vivo antidiabetic effects due to its non-toxic and digestive enzyme inhibitory properties. It can be recommended in additional pharmaceutical studies to develop novel therapeutics to manage diabetes mellitus. [ABSTRACT FROM AUTHOR]

Objective: To study the protective effect of sargassum polysaccharides （SP） on macrophage polarization and iron death induced by lipopolysaccharide （LPS） in order to determine whether SP has a regulatory effect on immune function. Methods: Isolating, purificating and identificating SP, a mouse macrophage RAW264.7 cell line inflammation model induced by LPS was established. The CCK-8 method was used to detect the effect of SP on macrophage proliferation. The levels of CD80, CD163, IL-6, IL-10, Arginine-1 （Arg-1）, inducible nitric oxide synthase （iNOS）, IL-6 and TNF-α in macrophages were measured by real-time fluorescence quantitative PCR （RT-qPCR） and Western blot. In order to understand the iron death of macrophages, ROS content was detected with ROS assay kit, and glutathione peroxid 4（ GPX4） expression was detected by Western blot. Results: SP were isolated successfully and identified not as furanose. High concentration of SP promote the proliferation of macrophages and had a significant protective effect on the inhibition of cell proliferation induced by LPS. SP could polarize RAW264.7 cells to M2 and antagonize M1 polarization induced by LPS. LPS could significantly increase ROS in macrophages, while SP could significantly decrease the level of ROS. The expression of GPX4 protein in macrophages induced by LPS was significantly decreased, and the expression was significantly up-regulated by high concentration of SP （P<0.05）. Conclusion: SP induces macrophages M2 polarization and antagonizes LPS induced M1 polarization and ferroptosis of macrophages. [ABSTRACT FROM AUTHOR]

Improving the immune system and growth of fish with seaweed instead of antibiotics can be a good idea for aquaculture. For this purpose, twenty four hundred red tilapia fish after adaptation to laboratory conditions were divided into four treatments with three replicates, and then fed diets contained control (without sargassum extract), 1, 2, and 3% of Sargassum ilisifulium extract for 8 weeks. The results showed that 2% Sargassum extract causes a significant increase in growth indices (specific growth factor, weight gain) and a significant decrease in food conversion ratio (P<0.05). All fish fed with different levels of Sargassum extract had more protein and less fat contents in the body compared to the control group (P<0.05). The amount of total protein, immunoglobulin, and lysozyme activity of the mucus in the fish fed with 2% Sargarsum extract was significantly higher than other experimental groups. (P<0.05). As a result, it is suggested to use 2% of dietary Sargassum extract to improve immunity and growth performance of red tilapia fish. [ABSTRACT FROM AUTHOR]

Sargassum horneri, a prevalent species of brown algae found along the coast of the northwest Pacific Ocean, holds significant importance as a valuable source of bioactive compounds. However, its rapid growth can lead to the formation of a destructive "golden tide", causing severe damage to the local economy and coastal ecosystems. In this study, we carried out de novo whole-genome sequencing of S. horneri using next-generation sequencing to unravel the genetic information of this alga. By utilizing a reference-guided de novo assembly pipeline with a closely related species, we successfully established a final assembled genome with a total length of 385 Mb. Repetitive sequences made up approximately 30.6% of this genome. Among the identified putative genes, around 87.03% showed homology with entries in the NCBI non-redundant protein database, with Ectocarpus siliculosus being the most closely related species for approximately one-third of these genes. One gene encoding an alkaline phosphatase family protein was found to exhibit positive selection, which could give a clue for the formation of S. horneri golden tides. Additionally, we characterized putative genes involved in fucoidan biosynthesis metabolism, a significant pathway in S. horneri. This study represents the first genome-wide characterization of a S. horneri species, providing crucial insights for future investigations, such as ecological genomic analyses. [ABSTRACT FROM AUTHOR]

Sargassum spp., a predominant seaweed speciesin Taiwan's coastal waters, exhibits a broad spectrum of bioactivities. In the present study, we investigated four Sargassum species viz., S. crassifolium, S. siliquosum, S. hemiphyllum, and S. hemiphyllum var. chinense for various bioactivities. From the four species, we made eight fucoidan extracts, namely SC, SCH, SS, SSH, SH, SHH, SHC, and SHCH with or without a compressional puffing pretreatment. The compressionalpuffing process increased the extraction yield of fucoidan and decreased levels of impurities (proteins and polyphenols). Among the eight fucoidans, SS (IC50 DPPH 0.46±0.01 mg/mL; IC50 ABTS•+ 0.09±0.00 mg/mL; FRAP value 67.4±0.9 μmol/g extract, vitamin C equivalent) and SHC (IC50 DPPH 0.53±0.17 mg/mL; IC50 ABTS•+ 0.11±0.00 mg/mL; FRAP value 55.1±0.6 μmol/g extract, vitamin C equivalent) displayed the highest antioxidant activity; SS (36.4±10.1% at 5 mg/mL for α-amylase; 96.3±0.2% at 1 mg/mL for α-glucosidase) and SHC (35.0±2.2% at 5 mg/mL for α-amylase; 96.5±0.2% at 1 mg/mL for α-glucosidase) showed the strongest α-amylase and α-glucosidase inhibitory activities; SH, SHH and SHC had the most potent anti-inflammatory activity; and SHH had a greatest protective effect against damage to pancreatic cells. Hence, SS, SH, SHH, and SHC may be effective health-promoting agents for nutraceutical products. [ABSTRACT FROM AUTHOR]

Background: Application of natural resources from the marine environment in the cosmeceutical industry is gaining great attention. Aim: This study pursues to discover the cosmeceutical potential of two Malaysian algae, Sargassum sp. and Kappaphycus sp. by determining their antioxidant capacity and assessing the presence of their secondary metabolites with cosmeceutical potential using non‐targeted metabolite profiling. Methods: Metabolite profiling using Quadrupole Time‐of‐Flight (Q‐TOF) liquid chromatography‐mass spectrometry (LC–MS) in the Electrospray Ionization (ESI) mode resulted in 110 putative metabolites in Sargassum sp. and 47 putative metabolites in Kappaphycus sp. and were grouped according to their functions. To the best of our knowledge, the bioactive compounds of both algae have not been studied in any great detail. This is the first report to explore their cosmeceutical potential. Results: Six antioxidants were detected in Sargassum sp., including fucoxanthin, (3S, 4R, 3'R)‐4‐Hydroxyalloxanthin, enzacamene N‐stearoyl valine, 2‐hydroxy‐hexadecanoic acid, and metalloporphyrins. Meanwhile, three antioxidants detected in Kappahycus sp., namely Tanacetol A, 2‐fluoro palmitic acid and idebenone metabolites. Three antioxidants are found in both algae species, namely, 3‐tert‐Butyl‐5‐methylcatechol, (−)‐isoamijiol, and (6S)‐dehydrovomifoliol. Anti‐inflammatory metabolites such as 5(R)‐HETE, protoverine, phytosphingosine, 4,5‐Leukotriene‐A4, and 5Z‐octadecenoic acid were also found in both species. Sargassum sp. possesses higher antioxidant capacity as compared to Kappahycus sp. which may be linked to its number of antioxidant compounds found through LC–MS. Conclusions: Hence, our results conclude that Malaysian Sargassum sp. and Kappaphycus sp. are potential natural cosmeceutical ingredients as we aim to produce algae cosmeceutical products using native algae. [ABSTRACT FROM AUTHOR]

According to estimates, 30% of Indonesia's urban population has NAFLD, with obesity being the leading risk factor. Being a maritime nation, ours has a sizable ocean region. The benefits of properly utilizing marine resources will be immense, especially when components from the marine biota are easily obtainable. Due to its high fiber content, particularly its soluble dietary fiber, seaweed is a good source of dietary fiber. It's also critical to understand and evaluate Sargassum's cholesterol-lowering mechanism. As per the research strategy plan document of Hang Tuah University, this study focuses on the technology of self-reliant medicinal raw materials. Specifically, it explores marine biota, which includes brown seaweed (Sargassum duplicatum), and evaluates its potential for treating Non-Alcoholic Fatty Liver Disease (NAFLD) through insilico testing. Based on the Structure Activity Relationship (SAR) docking data, what is the role of Sargassum in NAFLD? Based on the Structure Activity Relationship (SAR) docking outcomes, Sargassum duplicatum has a role in NAFLD through Fukosterol and Fallahydroquinone. [ABSTRACT FROM AUTHOR]

The present study aimed to conduct proximate composition analysis on seaweed Sargassum ilicifolium collected from the Mandapam region coast, Rameshwaram, Tamil Nadu, India. A result of seaweed Sargassum ilicifolium was followed. Moisture content was present (13.7% DW), ash (20.38% DW), protein (18.67% DW), lipid content (3.95% DW), crude fiber (18.05% DW), carbohydrate (36.33% DW), and total dietary fiber (3.92% DW). The composition of monosaccharides present is fucose (24.04) %, mannose (0.51%), galactose (0.69%), Xylose 0.92% and rhamnose (0.47%. Total carotenoids: 47.13 µg/ 100 g DW; chlorophyll-A: 157.19 µg/100 g DW; chlorophyll-B: 120.14 µg/100 g DW; Iodine 248.72 µg/100 g DW. Phytochemical analysis of steriods, phenols, tannins, saponins, flavonoids, terpenoids, and glycosides shows that all components are present. Mineral contents are Na (8592.62 Mg/100g DW), K (1849.17 Mg/100g DW), Mg (227.64 Mg/100g DW), Ca (1085.71 Mg/ 100g DW), Fe (307.41 Mg/100g DW), Se (5.1 Mg/100g DW), Mn (4.68 Mg/100g DW), P (19192 Mg/100g DW), Na/K ratio (4.97 Mg/100g DW), and total cation (34707.09 Mg/100g DW) observed. [ABSTRACT FROM AUTHOR]

Sargassum horneri, a brown seaweed, is known for its various health benefits; however, there are no reports on its effects on depression. This study aimed to investigate the antidepressant effects of S. horneri ethanol extract (SHE) in mice injected with corticosterone (CORT) and to elucidate the underlying molecular mechanisms. Behavioral tests were conducted, and corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and CORT levels were measured. A fluorometric monoamine oxidase (MAO) enzyme inhibition assay was performed. Neurotransmitters like serotonin, dopamine, and norepinephrine levels were determined. Moreover, the ERK-CREB-BDNF signaling pathway in the prefrontal cortex and hippocampus was evaluated. Behavioral tests revealed that SHE has antidepressant effects by reducing immobility time and increasing time spent in open arms. Serum CRH, ACTH, and CORT levels decreased in the mice treated with SHE, as did the glucocorticoid-receptor expression in their brain tissues. SHE inhibited MAO-A and MAO-B activities. In addition, SHE increased levels of neurotransmitters. Furthermore, SHE activated the ERK-CREB-BDNF pathway in the prefrontal cortex and hippocampus. These findings suggest that SHE has antidepressant effects in CORT-injected mice, via the regulation of the hypothalamic-pituitary-adrenal axis and monoaminergic pathway, and through activation of the ERK-CREB-BDNF signaling pathway. Thus, our study suggests that SHE may act as a natural antidepressant. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically important pathogens in the global swine industry over the past three decades. There is no licensed antiviral medication that can effectively control this infection. In the present study, the structure of SP-1 isolated and purified from Sargassum weizhouense was analyzed, and its antioxidant capacity and antiviral effect in MARC-145 cells against PRRSV were investigated. The results showed that SP-1 is a novel polysaccharide which mainly is composed of →4)-β-D-ManpA-(1→, →4)-α-L-GulpA-(1→ and a small amount of →4)-β-D-GalpA-(1→. PRRSV adsorption, replication, and release were all suppressed by SP-1. SP-1 therapy down-regulated mRNA expression of the CD163 receptor while increasing the antioxidant gene expression of Nrf2, TXNIP, and HO-1; increasing the protein expression of NQO1 and HO-1; and drastically reducing the protein expression of p-p65. The findings indicated that SP-1 reduces PRRSV adsorption, replication, and release through blocking the expression of the crucial CD163 receptor during infection. Meanwhile, SP-1 exerts antioxidant effects in PRRSV-infected cells through the activation of the Nrf2-HO1 signaling pathway. [ABSTRACT FROM AUTHOR]

The growth response and incorporation of As into the Sargassum horneri was evaluated for up to 7 days using either arsenate (As(V)), arsenite (As(III)) or methylarsonate (MMAA(V) and DMAA(V)) at 0, 0.25, 0.5, 1, 2, and 4 μM with various phosphate (P) levels (0, 2.5, 5 and 10 μM). Except As(III), algal chlorophyll fluorescence was almost similar and insignificant, regardless of whether different concentrations of P or As(V) or MMAA(V) or DMAA(V) were provided (p > 0.05). As(III) at higher concentrations negatively affected algal growth rate, though concentrations of all As species had significant effects on growth rate (p < 0.01). Growth studies indicated that toxicity and sensitivity of As species to the algae followed the trend: As(III) > As(V) > MMAA(V) ~ DMAA(V). As bioaccumulation was varied significantly depending on the increasing concentrations of all As species and increasing P levels considerably affected As(V) uptake but no other As species uptake (p < 0.01). The algae accumulated As(V) and As(III) more efficiently than MMAA(V) and DMAA(V). At equal concentrations of As (4 μM) and P (0 μM), the alga was able to accumulate 638.2 ± 71.3, 404.1 ± 70.6, 176.7 ± 19.6, and 205.6 ± 33.2 nM g-1 dry weight of As from As(V), As(III), MMAA(V), and DMAA(V), respectively. The influence of low P levels with increased As(V) concentrations more steeply increased As uptake, but P on other As species did not display similar trends. The algae also showed passive modes for As adsorption of all As species. The maximum adsorption of As (63.7 ± 6.1 nM g-1 dry weight) was found due to 4 μM As(V) exposure, which was 2.5, 7.3, and 6.9 times higher than the adsorption amounts for the same concentration of As(III), MMAA(V), and DMAA(V) exposure, respectively. The bioavailability and accumulation behaviors of As were significantly influenced by P and As species, and this information is essential for As research on marine ecosystems. [ABSTRACT FROM AUTHOR]

Simple Summary: The use of plant bioactive compounds like tannins to modulate ruminal biohydrogenation is a good strategy to optimize the fatty acid composition of ruminant-derived products, which are closely associated with human health. Differently from terrestrial tannins, there is little information on the effect of phlorotannins (PTs) from brown seaweeds on ruminal biohydrogenation. Thus, this study aimed to evaluate the effect of PT extract from Sargassum on in vitro rumen fermentation, fatty acid composition and bacterial community. The inclusion of PT extract had a positive effect on rumen fermentation by increasing dry matter digestibility and gas production and reducing ammonia-N concentration. Rumen biohydrogenation was profoundly inhibited by PTs as reflected in an increased unsaturated fatty acid and reduced saturated fatty acid production. The addition of PTs also changed the rumen bacterial community significantly with elevated carbohydrate-mediated bacteria. Correlation analysis found that Prevotellaceae_UCG-001, Anaerovorax, Ruminococcus, Ruminobacter, Fibrobacter, Lachnospiraceae_AC2044_group and Clostridia_UCG-014 might be involved in the biohydrogenation process. The results suggest that the inclusion of PTs in the diet improved rumen fermentation and fatty acid composition through modulating rumen microbiota. The fatty acid profiles of ruminant-derived products are closely associated with human health. Ruminal microbiota play a vital role in modulating rumen biohydrogenation (BH). The aim of this study was to assess the influence of dietary supplementation with phlorotannins (PTs) extracted from Sargassum on rumen fermentation, fatty acid composition and bacterial communities by an in vitro culture study. The inclusion of PTs in the diet increased dry matter digestibility and gas production, and reduced ammonia-N concentration and pH. PT extract inhibited rumen BH, increasing the content of trans-9 C18:1, cis-9 C18:1, trans-9 and trans-12 C18:2 and reducing C18:0 concentration. 16S rRNA sequencing revealed that PTs caused an obvious change in rumen bacterial communities. The presence of Prevotella decreased while carbohydrate-utilizing bacteria such as Prevotellaceae_UCG-001, Ruminococcus, Selenomonas, Ruminobacter and Fibrobacter increased. Correlation analysis between rumen FA composition and the bacterial microbiome revealed that Prevotellaceae_UCG-001, Anaerovorax, Ruminococcus, Ruminobacter, Fibrobacter, Lachnospiraceae_AC2044_group and Clostridia_UCG-014 might have been involved in the BH process. In conclusion, the results suggest that the inclusion of PTs in the diet improved rumen fermentation and FA composition through modulating the rumen bacterial community. [ABSTRACT FROM AUTHOR]

Increasing life expectancy of the human population has created a demand for functional food with anti-skin aging properties. Skin aging is a degenerative process caused by oxidative stress, inflammation, and matrix destruction. Some secondary metabolites isolated from marine macroalgae have been shown to exhibit potential dermatological benefits. The present study investigated the skin-protective properties of the ethanolic extract from Sargassum thunbergii (STEE) via antioxidant, anti-inflammatory, and antiwrinkle effects on mouse fibroblast L929 cells. The optimal extraction conditions for STEE were determined as follows: ratio of liquid to solid 25 : 1 mL/g, concentration of ethanol 40.2%, and extraction time 40 min. STEE was further purified by adsorption using a macroporous resin, SP700. STEE exhibited high DPPH radical and hydroxyl scavenging activity in vitro, enhanced the viability of H2O2-treated L929 cells, and reduced intracellular ROS generation in a dose-dependent manner. Superoxide dismutase and glutathione peroxidase activities and total antioxidant capacity in H2O2-treated L929 cells were increased while malondialdehyde content was markedly reduced by pretreatment with STEE. The inhibitory effect of STEE on H2O2-induced inflammation was shown by the downregulation of tumor necrosis factor-α, interleukin-6, cyclooxygenase-2, and inducible nitric oxide synthase. Furthermore, STEE reduced the matrix metalloproteinase-2 expression and inhibited collagenase and elastase activities. Moreover, STEE was nonirritating to human skin at 100 mg/mL according to the in vitro skin irritation test using EpiSkin™. Hemolysis assay showed that the hemolysis EC50 (1275 μg/mL) of STEE is much higher than the maximum effective concentration (125 μg/mL) against H2O2 exposure. Our results demonstrate that STEE may be a good candidate for the development of anti-skin aging functional food and cosmetic products. [ABSTRACT FROM AUTHOR]

The bloom of pelagic Sargassum in the Atlantic Ocean has become increasingly problematic, especially when the algae have beached. A build-up of decaying beached material has damaging effects on coastal ecosystems and tourism industries. While remote sensing offers an effective tool to assess the spatial and temporal patterns of Sargassum over large spatial extents, its use so far has been limited to a broad discrimination of Sargassum species from other macroalgae and floating vegetation. Knowledge on the spatial distribution of decayed material will help to support management strategies and inform targeted removal. In this study, we aim to characterise the spectral response of fresh and decayed Sargassum and identify regions of the spectra that offer the greatest separability for the detection and classification of decayed material. We assessed the spectral response of fresh and decayed Sargassum (1) in situ on the beach and (2) in mesocosm experiments where Sargassum samples were allowed to decay over time. We found a decrease in the magnitude of reflectance, noticeably in the visible region (400–700 nm), for decayed, in contrast to fresh, Sargassum. Separability analyses also showed that most spectral bands with a wavelength > ~540 nm will be capable of discriminating between fresh and decayed material, although the near-infrared region offers the greatest degree of separability. We demonstrate, for the first time, that there are clear differences in the spectral reflectance of fresh and decayed Sargassum with potential application for remote sensing approaches. [ABSTRACT FROM AUTHOR]

In this study, Sargassum latifolium (S. latifolium) n-hexane extract as a novel source for insecticidal bioactive compounds was investigated. The composition of the extract was identified by using GC-MS analysis. We performed the study on four types of insects and larvae sp (Sarcophaga bullata, Tribolium castaneum, Musca domestica, and Solenopsis invicta) which cause a deleterious impact on the crops and human health. We used scanning electron microscopy to show the destructive effects of S. latifolium extract on the exoskeleton. The treatment exhibited severe morphological changes and a high mortality rate. Also, different bioinformatic approaches were utilized to investigate the possible insecticidal mechanism of the extract. Molecular docking showed the potential of the compounds to be chitin synthase inhibitors. Besides, the toxicokinetic parameters of the most promising compounds were evaluated to assess the impact of using the extract as an insecticidal agent on human health. S. latifolium extract exhibited promising insecticidal activity and acceptable toxicokinetic properties as compared to other known pesticide groups. [Display omitted] • Sargassum latifolium extract has a promising insecticidal activity. • Utilization of the extract showed sever damage on the exoskeleton of the insects. • The compounds in the extract exhibited promising binding affinities with chitin synthase. • The identified compounds in the extract have safe toxicokinetic properties. [ABSTRACT FROM AUTHOR]

Sargassum fluitans was composted alongside sheep manure, in a transformative process that significantly enhanced the algal material's properties. Post the screening/washing/screening pretreatment, the content of total volatile solids escalated to 73.20%, while ash content reduced to 16.45%. Concurrently, lignin values surged to 30.12% as the biodegradability factor declined to 21%. The pretreatment decreased electrical conductivity from 11.60 to 1.32 DS/m. Employing a central composite design and response surface analysis pinpointed the optimal substrate combinations for carbon/nitrogen ratios of 35:1 and 25:1. The chosen combinations presented a high coefficient of determination (R2 = 0.9589, carbon/nitrogen ratio; R2 = 0.6584, pH), indicative of a robust statistical fit. Over a 45-day period, composting was conducted using bioreactors or biopiles, maintaining near-neutral pH values and temperatures slightly above ambient levels. The composting process reduced up to 94% of fecal coliforms in the 1:1 combination. Physicochemical analyses confirmed that the final product is a valuable compost-soil improver, with great potential for usage in organic agriculture, reforestation, and urban green spaces. Hence, this research underscores composting as an efficient technique in managing organic waste, including the emergent and seasonal Sargassum fluitans, thus addressing a pressing environmental concern with an innovative, effective solution. [ABSTRACT FROM AUTHOR]

We verified pre-settlement Sphoeroides spengleri (Bandtail Puffer) larvae by genetic sequencing and herein describe their morphology and pigmentation. The lead author collected the specimens on a North Carolina beach among stranded Sargassum, which may represent the first record of this species in the Sargassum community along the Mid-Atlantic Bight. Cleared and stained specimens exhibited a declivitous vertebral column that has been reported in few other members of the Tetraodontiformes. [ABSTRACT FROM AUTHOR]

The ordinary epidermal cells of various vascular plants are characterized by wavy anticlinal wall contours. This feature has not yet been reported in multicellular algal species. Here, we found that, in the leaf-like blades of the brown alga Sargassum vulgare, epidermal cells exhibit prominent waviness. Initially, the small meristodermal cells exhibit straight anticlinal contour, which during their growth becomes wavy, in a pattern highly reminiscent of that found in land plants. Waviness is restricted close to the external periclinal wall, while at inner levels the anticlinal walls become thick and even. The mechanism behind this shape relies on cortical F-actin organization. Bundles of actin filaments are organized, extending under the external periclinal wall and connecting its junctions with the anticlinal walls, constituting an interconnected network. These bundles define the sites of local thickening deposition at the anticlinal/periclinal wall junctions. These thickenings are interconnected by cellulose microfibril extensions under the external periclinal wall. Apart from the wavy anticlinal contour, outward protrusions also arise on the external periclinal wall, thus the whole epidermis exhibits a quilted appearance. Apart from highlighting a new role for F-actin in cell shaping, the comparison of this morphogenetic mechanism to that of vascular plants reveals a case of evolutionary convergence among photosynthetic organisms. [ABSTRACT FROM AUTHOR]

The current study was carried out at Rezu Khal to determine the ideal area for seaweed farming. Additionally, this investigation uncovered species of commercially productive and lucrative seaweed. Temperature, salinity, pH, dissolved oxygen (DO), conductivity, and Formazin Nephelometric Units (FNU) of surface water ranged from 20.9 to 26.2°C, 24 to 26.2?, 6.45 to 8.5, 92 to 105%, 33,256 to 64,267 µS/cm, and 11.1 to 42.8, respectively. Phosphate-phosphorus concentrations in surface water were 2.6-7.6 mg/L, 0.04-0.12 mg/L for nitrate-nitrogen, 0.002-0.04 mg/L for nitrite-nitrogen, 0.15-0.83 mg/L for silica, and 0.13-0.28 mg/L for ammonia. Three seaweed species (Gracilaria lemaneiformis, Hypnea musciformes, and Sargassum oligocystum) were cultivated in the selected areas. Two methods (net and long-line) were used for the culture. In this study, 15-20 kg of G. lemaneiformis were harvested every 15 days using the net method. H. musciformes gained 4 to 12 kg every 15 days. Although S. oligocystum thrived nicely, it was challenging to maintain its viability. The findings of this study indicate that seaweed farming is feasible and coastal residents may participate in seasonal income-generating endeavours in coastal waters. [ABSTRACT FROM AUTHOR]

Objective: The current study assessed hepatoprotective effects of Sargassum boveanum (S. boveanum) in cholestatic rats. To induce cholestasis, bile duct ligation (BDL) was utilized. Materials and Methods: Five groups of Sprague-Dawley rats including Sham and four BDL groups were assigned to receive vehicle (BDL-V) or ethanolic extract of S. boveanum at 100 (BDL-SE 100), 200 (BDL-SE 200) and 500 (BDL-SE 500) mg/kg/day for seven days. Results: BDL group receiving the vehicle (BDL-V) had substantially increased blood levels of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, total, and indirect bilirubin in comparison to the sham group. S. boveanum significantly decreased these variables compared to the BDL-V group. Hepatic malondialdehyde and tumor necrosis factor-α (TNF-α) level, and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and TNF-α gene expression were higher in BDL-V rats compared to the sham group but these were reduced markedly in BDL groups receiving S. boveanum in comparison to the BDL-V group. BDL-V group had a significantly lower hepatic glutathione value, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity and gene expression of SOD, GPx, Nrf2, HO-1 in comparison to the sham group. S. boveanum prevented the decrease of these variables. The histopathological assay showed marked bile ducts proliferation, portal inflammation, and hepatocellular damage in the BDL-V group and S. boveanum administration remarkably reduced hepatic injury. Gas chromatography-mass spectroscopy (GC-MS) analysis revealed that S. boveanum ethanolic extract contained 39 active compounds. Conclusion: S. boveanum treatment significantly ameliorated cholestatic hepatic injury via anti-oxidative and anti-inflammatory effects. [ABSTRACT FROM AUTHOR]

In this study, a PAMAM dendrimer was used as a surface-modifier to study the dyeability of cotton and silk fabrics using a sustainable dye generated from Sargassum sp. seaweed extracts. PAMAM dendrimer is a polymeric molecule characterized with multiple branched monomers containing numerous functional primary amino groups on the surface. These amine groups would readily act as a functional group similar to the structure of the natural protein fibers which is capable to improve the dyeability of textile fibers, especially with natural dyes. The crushed powder of dry Sargassum sp. was macerated for 48 h at 60°C in methanol. The cotton and silk materials were pre-treated with a PAMAM dendrimer at concentrations that were determined in advance before the dyeing process began. The electrokinetic capabilities of these surface-modified fabrics were next investigated by measuring their zeta potential with a SurPASS Electrokinetic Analyzer. Exhaust dyeing and simultaneous mordanting with vinegar, alum and iron were done on both untreated and treated cotton and silk fabrics with a certain amount of PAMAM dendrimer. The dyeing process was carried out at 85°C for intervals of 40, 60 and 80 min. It was discovered that surface-modified cotton and silk materials had a lower negative charge zeta potential, which enhanced their dyeability as well as the percent exhaustion and K/S values of the dyed fabrics. As a result of the surface modification, the zeta potential of the cotton fabric went from -20.40 to -14.63 mV. Similarly, the zeta potential of the surface-modified silk fabric, on the other hand, went from -36.80 to -26.85 mV. However, the percent exhaustion of surface-modified cotton and silk fabrics was increased to 21.17 and 39.99, respectively. Likewise, the K/S ratio of the surface-modified cotton fabric was raised from 0.06 to 0.20. Although the K/S value of the surface-modified silk fabric increased from 0.15 to 0.24. Additionally, the fastness properties of the dyed fabrics were graded as good to exceptional (between 4 and 5), except for lightfastness, which was classified as poor (rated between 3 to 5). Consequently, the sustainable dye from Sargassum sp. seaweed was successfully applied to cotton and silk fabrics. [ABSTRACT FROM AUTHOR]

The harmful impacts of the ongoing Sargassum invasions in the Atlantic Ocean include fish kills, skin and eye irritation, beach fouling, and declines in fisheries and tourism in West Africa and the Americas. This study was conducted to address important gaps in the non-market valuation literature and support the design of effective adaptation policies to reduce the harmful impacts of algal blooms. Contingent valuation survey data and linear mixed-effects regression models were utilized to estimate the drivers of willingness to pay (WTP) and willingness to contribute time (WTCT) for the management of invasive Sargassum seaweeds in Ghana. The study revealed that income, education, family size, years of residence, sex, attitudes, and political affiliation are significant drivers of WTP, while distance to the beach, occupation, house ownership, attitudes, and political affiliation are also significant predictors of WTCT. Hence, only attitudes about invasive seaweeds and political affiliation influence both WTP and WTCT. The findings suggest that for developing countries to generate enough funding and adequate economic support for coastal resource conservation, they should design local resource protection programs that give residents the option to contribute both time and money. [ABSTRACT FROM AUTHOR]

The Sargassum bed along the rocky intertidal region is highly productive and serves as a habitat for numerous associated species. In this study, the effect of habitat attributes (algal morphology) on the abundance and diversity of epifauna in Sargassum tenerrimum was investigated. Qualitative and quantitative analysis showed that the overall species diversity was high, and Hyale nuda, Gammaropsis sp. and Modiolus adriaticus were the most abundant epifaunal species observed. The abundance of epifauna varied significantly with time. Compared to pre-monsoon months (February to May), post-monsoon (October to January) had a greater diversity of S. tenerrimum associated epifauna. The diversity was particularly high in the month of November. Epifauna showed a positive correlation with the characteristic of algal morphology, indicating its influence on abundance and diversity. Hyale nuda being the most ubiquitous and abundant epifauna observed, the biotic interaction between S. tenerrimum and H. nuda was studied further. Close examination of the gut contents of H. nuda revealed that they graze and consume the epiphytic microalgae of S. tenerrimum, instead of the macroalgal fronds. This suggests that through this relationship, epibiosis in Sargassum may remain in control, while the amphipod derives food, shelter and protection from the predators. [ABSTRACT FROM AUTHOR]

Sargassum fusiforme polysaccharides (SFPs) have multiple activities. The fermentation of S. fusiforme by Lactobacillus can alter its polysaccharide properties and biological activities. In this study, three different Lactobacillus species (Lactobacillus plantarum (LP), Lactobacillus acidophilus (LA), and Lactobacillus rhamnosus (LR)) were selected to ferment S. fusiforme. The polysaccharides SFP (unfermented) and FSFP (fermented by LP, LA, or LR denoted as LP-SFP, LA-SFP, and LR-SFP, respectively) were extracted, and their physicochemical properties and biological activities were investigated. According to the results, fermentation caused significant changes in the physicochemical properties and biological activities of SFP. Specifically, FSFP showed a significant increase in uronic acid and fucose content and a significant decrease in molecular weight; LA-SFP and LR-SFP had stronger DPPH scavenging abilities; LR-SFP had the strongest inhibition of ROS production and cell mortality; LP-SFP and LR-SFP significantly increased SOD activity in zebrafish; LA-SFP had a significant effect on the proliferation of Lactobacillus plantarum; LP-SFP had a significant effect on the proliferation of Lactobacillus rhamnosus; and LA-SFP had a stronger food-excretion-promoting activity. In conclusion, the fermentation of Lactobacillus for the preparation of SFPs can change the physicochemical properties of polysaccharides and has broad potential for improving their biological activity. [ABSTRACT FROM AUTHOR]

Sargassum muticum (SM) is an invasive macroalgal species seasonally occurring in large quantities. While generally suitable for anaerobic digestion, recent studies resulted in low specific methane yields (SMYs), presumably due to salt, polyphenol, and high fiber contents of this marine biomass. In this study, the specific biogas yield (SBY) and SMY of SM alone as well as in co-digestion with wheat straw (WS) were investigated in batch tests at process temperatures of 44 ± 1.4 °C with a retention time of approx. 40 d. The pretreatment variants of SM were examined with regard to desalination and disintegration to potentially improve digestibility and to enhance the overall performance in anaerobic digestion. A sole mechanical treatment (pressing) and a thermo-mechanical treatment (heating and pressing) were tested. Batch assays showed that pressing increased the SMY by 15.1% whereas heating and pressing decreased the SMY by 15.7% compared to the untreated variant (87.64 ± 8.72 mL/gVS). Both anaerobic digestion experiments generally showed that co-digestion with WS can be recommended for SM, but the observed SBY and SMY were still similar to those of other studies in which SM was not pretreated. The mechanical pretreatment of SM, however, offers the potential to enhance the SMY in the anaerobic digestion of SM with WS, but further research is necessary to identify the optimum upgrading approaches since the overall SMY of SM is relatively low compared to other substrates that are commonly used in anaerobic digestion. In addition to anaerobic digestion, SM as an already available biomass could also be of interest for further utilization approaches such as fiber production. [ABSTRACT FROM AUTHOR]

The current work aims to provide a cost-effective and reliable micropropagation method of banana using some natural extract of unexplored potential seaweeds. We tried natural extract of eight different seaweeds (Caulerpa racemosa, Gracilaria edalis, Caulerpa paspaloides, Ulvalactuca, Sargassum tenerrimum., Caulerpa sertularioides, Sargassumwightii, Gracilaria corticata.) to check their role in in vitro growth and development of micropropagules and their potential in replacing commercial plant growth regulators (PGRs) in banana micropropagation. The in vitro developed shoots were allowed to grow on modified MS medium supplemented with different seaweed extracts and regularly subcultured on the same medium throughout the experiment. The growth and biochemical parameters were recorded and compared with micropropagules growing in a controlled environment (i.e., MS medium supplemented with/without standard PGRs). We found a significant increase in shoot length (highest in S'. tenerrimum, i.e. double as compared to negative control), shoot number (highest in G. edalis, i.e., three fold as compared to negative control) and fresh weight (S'. tenerrimum) of the banana micropropagules when grown under the influence of Liquid Seaweed Extract (LSE). This is comparable to growth observed in standard control conditions (i.e. positive control). However, addition of LSE of G. corticate, C. paspaloides and S', -wightii did not show any noteworthy effect on shoot length, shoot number and fresh weight. Total chlorophyll and other biomolecule accumulation in test propagules varied with types and concentrations of LSE. S', tenerrimum proved to be overall good growth promoter, as it caused maximum accumulation of chlorophyll (0.202±0.02 mg g"1) and protein (105±0.45 mg g"1) and significant and encouraging results in phenol, carbohydrates and proline. Our results show that seaweed can be potential source of beneficial natural compounds and it can be a cheaper option in banana micropropagation technology. [ABSTRACT FROM AUTHOR]

In marine systems, algal abundance and community composition is often heavily influenced by top-down control by herbivores. As a result, examining the extent to which native herbivores exert grazing pressure on non-native marine algae can provide valuable insight into mechanisms controlling invasion success. The purpose of this study was to examine the grazing preferences of two common intertidal and subtidal herbivores on three congeneric species of marine algae with unique colonization histories in San Diego, California, USA, to determine if grazing pressure, or lack thereof, may help explain invasion success. We provide evidence that neither native Sargassum agardhianum, nor non-native Sargassum horneri, are particularly palatable to purple urchins or black turban snails, but that non-native Sargassum muticum is consumed by both native herbivores. We also provide evidence that when given a choice of all three species neither herbivore exhibits a significant grazing preference for any algal species. We suggest that other mechanisms may determine the invasion success of the two non-native algal species and the overall distribution and abundance patterns of these species, and we discuss potential directions for future work.

There have been beaching events of the marine alga pelagic sargassum in coastal regions of the Caribbean Sea, West African countries, and the north-northeast region of Brazil since 2011. Its presence has caused environmental and socioeconomic impacts while several studies were conducted in order to understand the causes of this phenomenon, as well as alternatives to mitigate its impacts. The objective of this research was to evaluate pelagic sargassum biomass from beaching as a raw material for the manufacture of medium-density multilayer particleboards, aiming for an application that can reduce the impacts generated by the disposal of this seaweed on beaches and landfills. These are composed of 30% sargassum particles in their inner layer and 70% sugarcane bagasse particles on their outer layers, which are bonded with castor-oil-based polyurethane resin. A physical and chemical characterization was carried out in order to evaluate sargassum particles while physical and mechanical tests were carried out in order to evaluate the panels. Results were subsequently compared with indications from different particleboard standards. A life cycle assessment was carried out to complement the feasibility study of these panels and to compare their different manufacturing processes. The multilayer panels met the minimum requirements for physical and mechanical properties established by regulations, indicating that the Sargassum spp. biomass can be used as filling. The life cycle assessment study indicates that sargassum panels produced in the Belém, PA, Brazil, region present lower environmental impacts in four of seven evaluated categories when compared to conventional panels. Given the results obtained, the use of sargassum from beaching events as raw material for panels can be presented as an alternative for reducing social, economic, and environmental impacts in the regions affected by these events.

Hydrothermal liquefaction (HTL) is often mooted as a promising and sustainable processing methodology for converting biomass into usable products, including bio-oils, which can potentially alleviate humanity’s reliance on fossil fuels. To date, most HTL development work with novel biomasses has been undertaken at the laboratory scale in batch processes, and the results have been extrapolated to the theoretical continuous flow processes required for industrial uptake. Here, we assess the use of a novel continuous flow HTL system, applying it to Sargassum (seaweed) material and generating a bio-oil, which is assessed against typical crude oil fractions.

[Objectives] This study was conducted to investigate the application of Sargassumfusiforme (Harv.) Setch. in cigarettes. [Methods] Tobacco-specific nitrosamines in the smoke of cigarettes added with ethanol extract of S. fusiforme were determined, and the compounds related to the aroma of S. fusiforme were identified by flavor-smelling experiment. [Results] With the addition of the ethanol extract of S. fusiforme, the decrease in the total amount of four tobacco-specific nitrosamines in mainstream cigarette smoke reached 16.42%. The results of the flavor-smelling experiment showed that the aroma of S. fusiforme might be related to ( R)-5,6,7,7A-tetrahydro4,4,7A-trimethyl-2 ( 4H) -benzofuranone, glycerol, ethyl palmitate, methyl palmitate, ethyl linoleate, methyl ( Z, Z, Z) -9, 12, 15- octadecatrienoate, ethyl ( Z, Z, Z) -9, 12, 15-octadecatrienoate, phytol, and tetradecanoic acid. [Conclusions] The ethanol extract of S. fusiforme has the potential function of reducing the content of tobacco-specific nitrosamines in smoke and improving the taste of cigarettes. [ABSTRACT FROM AUTHOR]

Abstract The large‐scale proliferation of pelagic Sargassum in the Tropical Atlantic from 2011 has been the subject of increasing attention because of its negative consequences on the environment, fishing, and socioeconomic activities when stranding on coastal areas. This recurrent phenomenon presents strong seasonal and year to year variations. Anticipating the abundances and stranding on seasonal scale poses important challenges in terms of observations and modeling. We show that skillful seasonal forecast of Sargassum distribution can be achieved with up to 7 months in advance over the Tropical Atlantic, by integrating both transport and current knowledge on physiology of Sargassum. This forecast is designed to help marine stakeholders to develop mitigation and resilience strategies through anticipatory decision‐making.

The prevalence of food allergy, a common immune disorder associated with enteric dysbiosis, has been increasing in recent decades. Although immune-enhancing activity of Sargassum-derived polysaccharides has been reported, the influence of Sargassum-derived polysaccharides extract (SP) and even oligosaccharides extract (SO) on alleviating allergic responses remains unclear. Herein, SP and SO were prepared, and the residues (SR) was also harvested. The immunomodulatory and anti-allergic activities of these Sargassum samples were investigated in a murine model of food allergy. Daily treatment of SO, SP and SR by gavage exerted distinctive effects on modulating serum antibody production, regulating systemic and intestinal T cell responses, suppressing pro-inflammatory cytokine production, and attenuating allergic enteritis. In parallel, the improvement of enteric dysbiosis was observed with Bacteroides acidifaciens and Akkermansia muciniphila as the predominant microbes in response to Sargassum samples. Collectively, SO, SP and SR are novel candidates for developing functional foods against allergic enteritis and dysbiosis.

Introduction: The textile, paper, rubber, plastic, leather, cosmetics, pharmaceutical, and food sectors extensively use malachite green (MG). In spite of this, it has mutagenic, carcinogenic, teratogenic, and, in some circumstances causes chronic respiratory disease. Objectives: In this work, we used sodium alginate, Sargassum latifolium aqueous extract, and their silver nanoparticles to test their potential as inexpensive adsorbent agents to remove malachite green dye from aqueous solutions. Methods: The removal rate of MG was determined using a series of bioadsorption experiments. Besides, the effect of different factors on bioadsorption, such as pH, adsorbent dose, contact time (min), and different concentrations of MG dye was investigated. Results: The removal efficiency of MG dye by alginate nanoparticles, alginate, Sargassum latifolium aqueous extract, and S. latifolium aqueous extract nanoparticles was 91, 82, 84, and 68 respectively. The optimal conditions for bioadsorption of malachite green dye were pH 7, a contact time of 180 min, and an adsorbent dose of 0.02 g. The adsorption isotherm was fitted to Langmuir and Freundlich isotherm. Also, UV and FT–IR before and after the bioadsorption of MG were performed to confirm the bioadsorption process. Conclusion: Our results indicated that alginate nanoparticles were the most effective bioadsorbent agent. [ABSTRACT FROM AUTHOR]

Sargassum spp. flood the Caribbean coastline, causing damage to the local economy and environment. Anaerobic digestion (AD) has been proposed as an attractive option for turning macroalgae into valuable resources. Sargassum spp. has a complex composition that affects the microbial composition involved in AD which generates a low methane yield. This study aimed to improve the methane yield of pelagic Sargassum, using different energy-saving pretreatments and identifying the microbial community associated with methane production. We applied different energy-saving pretreatments to algal biomass and assessed the methane yield using a biomethane potential (BMP) test. The microbial communities involved in the AD of the best- and worst-performing methanogenic systems were analyzed by high-throughput sequencing. The results showed that pretreatment modified the content of inorganic compounds, fibers, and the C:N ratio, which had a strong positive correlation with BMP. The water washing pretreatment resulted in the best methane yield, with an increase of 38%. DNA metabarcoding analysis revealed that the bacterial genera Marinilabiliaceae_uncultured, DMER64, Treponema, and Hydrogenispora, as well as the archaea genera Methanosarcina, RumEn_M2, Bathyarchaeia, and Methanomassiliicocus, dominated the microbial community with a high methane yield. This study is the first to demonstrate the microbial community structure involved in the AD of Sargassum spp. The pretreatments presented in this study can help overcome the limitations associated with methane yield. [ABSTRACT FROM AUTHOR]

Algal extracts are used in the environmentally safe and economically advantageous biosynthesis of silver nanoparticles, which does not require the use of hazardous chemicals, high temperatures, pressures, or energies. In the current study, we created silver nanoparticles from the extract of the marine brown alga Sargassum latifolium, analyzed them with Transmission Electron Microscopy (TEM), FTIR, and UV-visible spectrophotometers, and used them to show how well they could remove Fe (II) ions from aqueous solutions. UV scan analyses of S. latifolium aqueous extract of silver nanoparticles showed a maximum peak at 450 nm. This peak is considered a characteristic peak for silver nanoparticles. Also, FTIR analysis of S. latifolium aqueous extract revealed various functional groups such as – OH, –NH, –CH, –COOH, CO, and C–C, which are responsible for bioadsorption of Fe (II). TEM also demonstrated that the synthesized nanoparticles were spherical, distinct, and regular, with particles size about 6.03–15.16 nm. S. latifolium aqueous extract silver nanoparticles were more effective than its aqueous extract in removing Fe (II) from an aqueous solution. The removal efficiency of Fe (II) by nanoparticles was 83%, while by the aqueous extract was 69%. The optimal conditions for bioadsorption of Fe (II) were pH 4, contact time 150, and adsorbent dose 0.01 g. No work has been reported yet for utilization of marine brown algae Sargassum latifolium aqueous extract to synthesize silver nanoparticles and its application of Fe (II) bioadsorption from aqueous solution. [ABSTRACT FROM AUTHOR]

Though nitrogen fixation by epiphytic diazotrophs on pelagic Sargassum has been recognized for decades, it has been assumed to contribute insignificantly to the overall marine nitrogen budget. This six-year study reframes this concept through long-term measurements of Sargassum community nitrogen fixation rates, and by extrapolating mass-specific rates to a theoretical square meter portion of Sargassum mat allowing for comparison of these rates to those of other marine and coastal diazotrophs. On 24 occasions from 2015 to 2021, rates of nitrogen fixation were measured using whole fronds of Sargassum collected from the western edge of the Gulf Stream off Cape Hatteras, North Carolina. Across all dates, mass-specific rates ranged from 0 to 37.77 μmol N g-1 h-1 with a mean of 4.156 μmol N g-1 h-1. Extrapolating using a mat-specific density of Sargassum, these rates scale to a range of 0 to 30,916 μmol N m-2 d-1 and a mean of 3,697 μmol N m-2 d-1. Quantifying this community's rates of nitrogen fixation over several years captured the sometimes-extreme variability in rates, characteristic of marine diazotrophs, which has not been reported in the literature to date. When these measurements are considered alongside estimates of the density of pelagic Sargassum, rates of nitrogen fixation by Sargassum's epiphytic diazotrophs rival that of their coastal macrophyte and planktonic counterparts. Given Sargassum's wide and expanding geographic range, the results of this study suggest this community may contribute reactive nitrogen on a meaningful, basin-wide scale, which merits further study. [ABSTRACT FROM AUTHOR]

Since 2011, substantial amounts of pelagic Sargassum algae have washed up along the Caribbean beaches and the Gulf of Mexico, leading to negative impacts on the economy and the environment of those areas. Hence, it is now crucial to develop strategies to mitigate this problem while valorizing such invasive biomass. This work deals with the successful exploitation of this pelagic Sargassum seaweed for the fabrication of carbon materials that can be used as electrodes for supercapacitors. Pelagic Sargassum precursors were simply pyrolyzed at temperatures varying from 600 to 900 °C. The resultant carbonaceous materials were then extensively characterized using different techniques, such as nitrogen adsorption for textural characterization, as well as X-ray photoelectron (XPS), Fourier transform infrared spectroscopies (FT-IR) and scanning electron microscopy (SEM), to understand their structures and functionalities. The electrochemical properties of the carbon materials were also tested for their performance as supercapacitors using cyclic voltammetry (CV), the galvanostatic method and electrochemical impedance spectroscopy analyses (EIS). We managed to have a large specific surface, i.e., 1664 m2 g−1 for biochar prepared at 800 °C (CS800). Eventually, CS800 turned out to exhibit the highest capacitance (96 F g−1) over the four samples, along with the highest specific surface (1664 m2 g−1), with specific resistance of about 0.07 Ω g −1. [ABSTRACT FROM AUTHOR]

Background: Fucoidan is sulfated polysaccharide that has gastroprotector activity, and it is distributed in brown algae cell walls. Currently, there is no method for fucoidan analysis in compendia. Furthermore, analysis of Fucoidan is proven to be challenging due to the lack of chromophores and its high polarity. Objective: To develop the optimal condition of TLC-Densitometry method for fucoidan analysis in Sargassum sp. aqueous extract and to evaluate the stability of Fucoidan as a preliminary study. Methods: Chromatography was performed on Silica gel 60F254 TLC-plate as a stationary phase. The developed plate was stained with H2SO4 10% in absolute ethanol and heated in oven at 105°C for 15 minutes. Optimization is carried out by determining composition of the mobile phase, analytical wavelength, and spotting volume. Stability test of Fucoidan in standard and extract solution at 0, 4, 8, and 24 hours also 0 and 60 minutes after derivatization. Results: The optimal condition which produces a good separation of Fucoidan was achieved by using n-butanol:methanol: water (10:6:10 v/v/v) as a mobile phase, 400 nm as an analytical wavelength, and 1 µl as a spotting volume. Fucoidan was stable after storage until 24 hours. The stained spots were stable until 60 minutes after derivatization. Conclusion: Optimal condition of the TLC-Densitometry method for Fucoidan analysis was selective and can be applied to stability tests in preliminary study. Fucoidan was stable in standard solution and extracted solution until 24 hours after storage at 4°C, and the stained spots were stable until 60 minutes after derivatization. [ABSTRACT FROM AUTHOR]

Over 90% of introduced marine species are seaweeds. Seaweeds rely on their microbiome for host settlement, nutrition, development and health. As such, it is likely that microbiomes are involved in seaweed invasions. Sargassum muticum, indigenous to Southeast Asia, inhabits the North-east Atlantic from Norway to Morocco. This is the only known successful case of a non-clonal marine invader with almost no genetic variation over its large NE Atlantic introduced range. This makes it a very interesting model to study an invasive seaweeds microbiome, as it practically uncouples host genetic variation from microbiome variation. Associated bacteria potentially contribute to the plasticity and acclimation of S. muticum leading to its success over the last 50 years. Dispersing host organisms can either bring their acquired microbes along or obtain new ones locally, following the mutualist and generalist host hypothesis, respectively. We used partial 16S rRNA gene amplicon sequencing to characterize the total and core microbiome across S. muticum structures/tissues from five NE Atlantic regions, from Norway to Morocco, covering over 30° of latitude. In contrast to host genotypes, highly diverse, regional, total and core microbiomes, with differentiation levels depending on tissue, bacterial community structure were detected. Atlantic S. muticum follows the generalist host hypothesis, possibly recruiting a new microbiome in each new region. This host promiscuity may promote the invasiveness of S. muticum. Diversity was lower in the young/annual tissues compared with the older tissues for the total bacterial community, suggesting that these are mostly transitory bacteria accumulating over time in the older parts. The total core microbiome included 10 OTUs, representing dominant community members commonly found in other seaweeds' cores. The core Granulosicoccus OTU followed a clear regional pattern where northern and southern regions clustered differentially, suggesting a regional signature even at an OTU level. North-east (NE) Atlantic Sargassum muticum microbiome differentiation does not match host genetic background. NE Atlantic S. muticum shows a geographic region and tissue-specific total and core bacterial community matching bestthe generalist host hypothesis. Core OTU – the bacterium Granulosicoccus – shows a strong regional specialization. [ABSTRACT FROM AUTHOR]

Due to climate change and its associated factors, there has been an increased influx of pelagic brown algae biomass drifting freely in the Caribbean Sea in recent years. Its use as an industrial recyclable material is feasible, although pelagic Sargassum species have Arsenic (As) heavy metal content; among 531 tested pesticide residues applied to vegetables, fruit, infant food, herbs, and spices, zero were found in Sargassum. Sargassum also contains sulfated polysaccharides and oligosaccharides, which are known to be beneficial immunomodulators. Our results thus suggest Sargassum to be a functionally useful organic material in small quantities as an additive in animal feed. With improved chemical extraction methods, it could also be highly effective in adjusted proportions in cosmetics and for other industrial uses. A viable solution for predicting and tracking the large-scale movements of algal masses is provided. Furthermore, a method for addressing increasing Sargassum influx is proposed via its use as an industrial recyclable material following composition analysis, evaluation and safety assessments for cosmetic use, and research and design of new beauty products and other functional cosmetics. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of Sargassum fusiforme extract (SFE) on melanogenesis and its mechanism both in vitro and ex vivo. The melanogenic-inducing effect of SFE was evaluated using a melanin contents assay and a cellular tyrosinase activity assay. To investigate whether SFE could protect melanocytes against oxidative stress, hydrogen peroxidase was used. The molecular mechanism underlying the effect of SFE on melanogenesis was determined via Western blot analysis of tyrosinase, a microphthalmia-associated transcription factor (MITF), and a phosphorylated cAMP response element-binding protein (p-CREB) expression. The degree of pigmentation in a 3D skin model was determined by measuring the L* values. Contents of melanin in ex vivo human hair follicles were evaluated via Fontana–Masson staining. SFE significantly increased melanin contents and cellular tyrosinase activity in human epidermal melanocytes. SFE also increased the phosphorylation of CREB and the protein levels of tyrosinase and MITF. Moreover, SFE attenuated oxidative stress-induced cytotoxicity and depigmentation. Finally, the melanogenesis promoting effect of SFE was confirmed in both a 3D skin model and ex vivo human hair follicles. These findings suggest that SFE can induce melanogenesis via the cAMP/PKA/CREB signaling pathway in human epidermal melanocytes through its hyperpigmentation activity. [ABSTRACT FROM AUTHOR]