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Long used in East Asian cuisine and traditional medicine, the brown seaweed Hizikia fusiformis (also known as Sargassum fusiforme or Hizikia fusiforme) is also referred to as "Hijiki." Given its abundant environmental and bioactive characteristics, it has received considerable attention. This systematic review aimed to present comprehensive data from the existing literature on the environmental and bioactive characteristics of H. fusiformis. Using three databases to search for published studies on related fields between 2002 and 2023, 1344 papers were screened and narrowed down to a set of 49 papers by the predetermined criteria. Evidence shows that H. fusiformis is a promising resource in the environmental protection and bioactive domains. Overall, more research and methods are needed to organically combine the development of H. fusiformis in the environmental and bioactive fields to gain greater economic benefits and environmental protection capabilities. [ABSTRACT FROM AUTHOR]

Sargassum (brown seaweed) is free-floating brown algae found on ocean shores in large quantities littering shorelines and causing visual and olfactory nuisances affecting the tourism and fishery industries. In this study, Sargassum is valorized to ultraporous carbon material via hydrothermal carbonization (HTC) at temperatures 180, 220, and 260 °C followed by KOH activation. The synthesized ultraporous superactivated hydrochar (SAH) is then analyzed by physical (thermogravimetric analysis and ultimate analysis), morphological (Brunauer-Emmet-Teller surface area and scanning electron microscopy), and chemical characterizations (Fourier Transform Infrared Spectroscopy and Boehm titration). It was found that the SAH proved to be thermally stable, carbon-dense with very high BET surface area ranging from 1216.92 to 1404.09 m2/g, total pore volume ranging from 0.69 to 0.77 cm3/g and micropore volume ranging between 0.32 to 0.36 cm3/g. Substantial surface oxygen-containing acidic functional groups were present on the SAH extending from 356.04 to 452.82 μmol/g. These physical and morphological alterations made SAH an excellent adsorption material with Methylene blue adsorption where as high as 641.03 mg/g at room temperature and 714.29 mg/g at 37 °C. Influential adsorption parameters were investigated, showing high maximum adsorption at solution pH 12, 24 h contact time, and under 37 °C respectively. Additionally, SAH showed selective adsorption behavior towards methylene blue in the presence of methyl orange. The possible adsorption mechanisms associated with the uptake of methylene blue are pore filling and electrostatic attraction being the dominant adsorption mechanisms. From adsorption isotherm modeling, the Langmuir model has proven to be the best fit with R2 at 0.99. A thermodynamic study was conducted confirming spontaneous adsorption (negative ΔG) favoring higher adsorption temperatures with an entropy-driven process (ΔH = 11.57 kJ/mol, ΔS = 169.94 J/mol). From kinetic modeling, Elovich model showed the best fit describing chemisorption characteristics. [ABSTRACT FROM AUTHOR]

Since 2011, holopelagic Sargassum have been massively stranding in the coastal environments of the Caribbean Islands inducing damages to coastal ecosystems, public health and the economy. To limit the risks associated with Sargassum stranding, floating barriers with nets can be placed in front of sensitive areas, to divert Sargassum away from the coast. To evaluate the potential transfer of metallic trace element (MTE) from Sargassum to adjacent marine life, seagrasses (Halophila stipulacea, Thalassia testidinum) and urchin (Lytechinus variegatus) were sampled, both close (0 m) and far (200 m) from barriers installed during 4 years in two bays: Baie Cayol (BC) and Cap Est (CE) in Martinique (FWI). A bay without barriers Baie-Tresor (BT) was also sampled in order to compare the effects of Sargassum accumulated in a natural environment versus an environment with floating barriers. The short-term effects of barriers were evaluated by measuring the evolution of MTE after four days, in the algae (Dictyota spp.), located close to Sargassum accumulations. All sampling was realized during two periods of active (July 2021) and reduced (January 2022) Sargassum stranding. The measured concentrations of 19 metal(loid)s trace elements revealed that the proximity of Sargassum to the barriers did not increase MTE concentration. The absence of increase in MTE was observed all sites (BT, BC and CE) and during periods of limited and important Sargassum stranding. Similarly, translocations of Dictyota close to Sargassum accumulations did not reveal any increase in MTE concentrations in the algae after 4 days. The present study suggests that the use of barriers to manage Sargassum stranding would not constitute an important threat of MTE contamination of marine environments. [ABSTRACT FROM AUTHOR]

Sargassum species play a key role in habitat formation in tropical and subtropical regions; however, species identification has been hampered by the phenological plasticity exhibited in response to environmental conditions and life history. Molecular phylogenetics has challenged taxa circumscriptions and proven critical in delimiting species in this genus. Yet, the Atlantic species of Sargassum remain poorly understood, and recent studies have shown low molecular diversity between the species in the NW Atlantic. Here, we expand the taxon sampling to the NE Atlantic to assess the diversity of Sargassum in the Atlantic basin, based on a comprehensive morphological and multigene approach. We selected genes commonly used in delineating species in this genus (ITS2, rbcLS, cox3, mtsp) and explored additional markers (cox2, nad6, psbC, clpC, atpB) to infer the phylogenetic relationships between the morphospecies observed in the NE Atlantic. Phylogenetic analyses using single‐gene and multigene alignments including 185 new sequences confirmed the low molecular diversity and supported the distinction of a single clade in Sargassum section Sargassum of N Atlantic benthic species. In contrast, morphological analysis resulted in the identification of 10 species and three new morphospecies that we described here but opt not to equate to species until further molecular evidence is available. Our results were congruent with previous findings from the NW Atlantic and highlight the morphological and ecological diversity of Sargassum in the Atlantic. These results suggest a recent colonization and incipient speciation of Sargassum in the Atlantic basin and showcase the need of further high‐throughput analyses. [ABSTRACT FROM AUTHOR]

Benthic metabolism and net carbon accumulation in mangroves sediments strongly depend on the quantity and quality of organic matter (OM) supplied, including material brought by coastal waters such as the macroalgae Sargassum spp. Mesocosms were used to assess the effect of eutrophication by Sargassum on mangrove sediments. The concentration of fatty acids (FAs), organic carbon and its carbon isotopic signature, and the sediments–air CO2 fluxes were used to follow the evolution of sedimentary OM in surface and subsurface sediments for 60 d. Sargassum beaching shifted microbial and crab metabolism, leading to a preferential degradation of the labile fraction of OM from both Sargassum (δ13C = −17.7‰ and high concentration of essential FAs) and mangrove leaves (δ13C: −28.9‰ and high concentrations of 18:2ω6 and 18:3ω3). Fatty acids composition of crabs hepatopancreas revealed they preferentially fed on Sargassum and these invertebrates also increased the particulate OM tidal export. In addition, microbial activity at the sediment surface was enhanced, as revealed by strong production of branched FAs and higher CO2 fluxes in mesocosms containing Sargassum. However, Sargassum beaching also increased the transfer and preservation of more refractory OM from mangrove leaves found in higher quantity in subsurface sediments (6–8 cm) after 60 d. Inputs of macroalgae induced a negative priming effect and enhanced the preservation of blue carbon in the sediments. This negative priming effect was enhanced by crab activities. These biotic interactions that include microbial communities apparently make mangrove efficient in storing carbon in a context of growing eutrophication of the tropical ocean. [ABSTRACT FROM AUTHOR]

Artificial Light at Night (ALAN) is an emerging global stressor that is likely to interact with other stressors such as warming, affecting habitat‐forming species and ecological functions. Seaweeds are dominant habitat‐forming species in temperate marine ecosystems, where they support primary productivity and diverse ecological communities. Warming is a major stressor affecting seaweed forests, but effects of ALAN on seaweeds are largely unknown. We manipulated ALAN (0 lx vs. 25 lx at night) and temperature (ambient vs. +1.54°C warming) to test their independent and interactive effects on the survival, growth (biomass, total‐, blade‐ and stipe‐length) and function (photosynthesis, primary productivity and respiration) on the juveniles of two habitat‐forming seaweeds, the kelp Ecklonia radiata and the fucoid Sargassum sp. Warming significantly increased Ecklonia mortality; however, ALAN did not affect mortality. ALAN had positive effects on Ecklonia biomass, total and blade growth rates and gross primary productivity; however, warming largely counterbalanced these effects. We found no significant effects of warming or ALAN on Ecklonia photosynthetic yield, stipe length, net primary productivity or respiration rates. We found no effects of ALAN or warming on Sargassum for any of the measured variables. Synthesis. Our findings indicate that ALAN can have positive effects on seaweed growth and functioning, but such effects are likely species‐specific and can be counterbalanced by warming, suggesting an antagonistic interaction between these global stressors. These findings can help us to predict and manage the effects of these stressors on seaweeds, which underpin coastal biodiversity. [ABSTRACT FROM AUTHOR]

This study aimed to identify specific therapeutic targets for oral squamous cell carcinoma (OSCC) that metastasize from breast cancer (BC) by using network pharmacology. The Gene Expression Omnibus for OSCC and BC served as the source of gene expression datasets and their analysis. Upregulated genes and the common intersecting genes of these cancers were determined along with that of the phytochemicals of F. sargassum to predict the pharmacological targets. Further, gene enrichment analysis revealed that their metastasis signature and metastasis targets were determined via a protein interaction network. Molecular docking and pharmacokinetic screening determined the potential therapeutic phytochemicals against the targets. The interaction network of 39 genes thus identified encoding proteins revealed HIF1A as a prominent metastasis target due to its high degree of connectivity and its involvement in cancer-related pathways. Molecular docking showed a strong binding affinity of isonahocol D2, a sargassum-derived compound with HIF1A, presenting a binding energy of −7.1 kcal/mol. Further, pharmacokinetic screening showed favorable ADME properties and molecular dynamics simulations showed stable interactions between isonahocol D2 and HIF1A, with significant stability over 100 ns. This study's results emphasized that isonahocol D2 is a promising therapeutic candidate against HIF1A in OSCC metastasized from breast cancer in translational medicine. [ABSTRACT FROM AUTHOR]

Dissolved organic carbon (DOC) released by macroalgae supports coastal ocean carbon cycling and contributes to the total oceanic DOC pool. Salinity fluctuates substantially in coastal marine environments due to natural and anthropogenic factors, yet there is limited research on how salinity affects DOC release by ecologically important macroalgae. Here we determined the effect of short‐term salinity changes on rates of DOC release by the habitat‐forming fucalean seaweed Sargassum fallax (Ochrophyta). Lateral branches (~4 g) cut at the axes of mature individuals were incubated across a salinity gradient (4–46) for 24 h under a 12:12 light:dark cycle, and seawater was sampled for DOC at 0, 12, and 24 h. Physiological assays (tissue water content, net photosynthesis, respiration, tissue carbon, and nitrogen content) were undertaken at the end of the 24‐h experiment. Dissolved organic carbon release increased with decreasing salinity while net photosynthesis decreased. Dissolved organic carbon release rates at the lowest salinity tested (4) were ~3.3 times greater in the light than in the dark, indicating two potential DOC release mechanisms: light‐mediated active exudation and passive release linked to osmotic stress. Tissue water content decreased with increasing salinity. These results demonstrate that hyposalinity stress alters the osmotic status of S. fallax, reducing photosynthesis and increasing DOC release. This has important implications for understanding how salinity conditions encountered by macroalgae may affect their contribution to the coastal ocean carbon cycle. [ABSTRACT FROM AUTHOR]

Holopelagic Sargassum spp. (sargassum) are the founding species of diverse communities in the Sargasso Sea. Since 2011, a new area of concentration of these algae was formed in the equatorial North Atlantic and Caribbean Sea. We analyzed elemental composition, and the small mobile fauna associated with sargassum collected at 41 stations, during two expeditions in the Caribbean Sea in 2018 and 2019, that covered open-sea stations in two marine ecoregions, and coastal stations (< 20 km from the shore) in one of them. Metal(loid) concentrations generally followed the order As > Zn > Cu > Cd > Se > Pb > Hg, and contents of As (195.5 ± 13.7 µg g−1), Cd (0.59 ± 0.02 µg g−1), and Hg (0.22 ± 0.09 µg g−1) were highest in S. fluitans III in the South-Western-Caribbean ecoregion. Mean [Ctot] per ecoregion varied between 26.1 and 30.1 mg g−1, and variation was mainly accounted for by higher [Cinorg] (likely produced by calcifying epibionts) in the South-Western Caribbean (10.12) compared to the Western Caribbean (8.92 and 7.19); this tendency that was also found for [Ntot] (between 1.06 and 1.27), and these contents were positively correlated with seawater chlorophyll concentrations. Sixty-six taxa of mobile fauna were identified, with the phylum Arthropoda being most abundant and diverse. The faunal community composition was similar in both open-sea regions, but differed in the coastal stations, which was mostly explained by differential relative abundance of Latreutes fucorum, Carpias minutus, Litiopa melanostoma, and some fish species. The Caribbean open-sea rafts harbor a diverse fauna comparable to that found in the Sargasso Sea, and likely provide similar ecosystem services, and thus merit similar protective efforts as those directed towards sargassum in the Sargasso Sea. [ABSTRACT FROM AUTHOR]

The spread of sargassum on beaches in Africa, Brazil, Central America, and the Caribbean has increased to become a social, environmental, and economic problem. In recent years, the presence of biomass on the coasts of the Mexican Caribbean has been recorded as ≈2360 m3 Km−1, reaching up to 200 m wide in the northern part of the coasts. Its removal from the coast and, later, the continent is one of the strategies implemented to mitigate its impact on land. Several studies have reported the seasonality of and geographic variation in sorbed metals in sargasso. However, it is unknown whether these metals can mobilize or remain in sargassum tissue once they reach accumulation sites. This study included seawater, sargassum tissue as a consortium, and S. natans and S. fluitans, as well as the leachate generated in the process of degradation per se and percolated by rain. Of the 10 metals evaluated (As, B, Fe, Zn, Mn, Cd, Al, Ni, Cu, and Pb for water, tissue, and leachate), only B is recurrent in water from the north of the Mexican Caribbean, in addition to traces of Al and Fe. Meanwhile, in tissue, the results coincide with those of previous studies, where As is recurrent, although its concentration varies with the mentioned variability. The leachate showed that four to eight metals of those present in the tissue were detected, including As, Fe, and Al, which represent a potential impact on coastal systems and infiltration into shallow water table areas. [ABSTRACT FROM AUTHOR]

Both the aquatic ecosystem and human health are at risk from radioactive elements like uranium(VI) (U(VI)) and thorium(IV) (Th(IV)). Therefore, their elimination and removal from water is of vital importance. In this study, Sargassum aquifolium macroalgae (SAM) powder was used to remove U(VI) and Th(IV) ions from aqueous solution as a new, inexpensive, and readily available biosorbent. The prepared SAM was characterized using several instruments including FTIR, XRD, TGA, and SEM-EDXS. To evaluate the sorption performance, five operating conditions were investigated, namely, solution pH, sorbent mass, contact time, metal concentration, and temperature using the batch technique. The pseudo second order equation adequately describes the sorption of U(VI) and Th(IV) ions by SAM sorbents, according to sorption kinetic studies. The sorption isotherm results corresponded well with the Langmuir sorption model, with U(VI) and Th(IV) having maximal sorption capacities of 20.4 mg g−1 and 24.1 mg g−1, respectively. Parameters of thermodynamics indicated that the sorption of U(VI) and Th(IV) ions onto SAM is possible, spontaneous, exothermic, and entropy-driven. According to desorption tests, the most effective desorption reagent for both metal cations is 0.1 mol L−1 HNO3. This research has shown that the treated SAM sorbent has high efficiency in the removal of U(VI) and Th(IV) ions from real wastewater samples. [ABSTRACT FROM AUTHOR]

AbstractSargassum polycystum is among the seaweed species in the Philippines that are considered coastal waste after drifting on the shorelines. Although there has been a report on the potential of S. polycystum as a biostimulant for certain crops, its utilization as a hydroponic nutrient solution is not yet thoroughly analyzed. Thus, a study utilizes various ratios of S. polycystum seaweed extract (SE) mixed with commercial hydroponic nutrient solution (CHNS) to the growth and yield of green leaf lettuce grown under the Kratky method of hydroponic system. Treatments are 100% CHNS and percentage replacements of CHNS with SE (25%, 50%, and 75%, respectively). The result shows a 10.53% increase in lettuce plant height grown under 25% and 50% SE compared to 100% CHNS. A similar result is also observed in the lettuce leaf width (14.29%), leaf length (7.14%), and plant weight (22.41%). Regarding root length, replacing 50% SE resulted in longer root length (44.83%) and more leaves (10%) compared to lettuce plants grown under 100% CHNS. However, replacement of SE beyond 50% is detrimental to leaf length and comparable to all growth and yield parameters with 100% CHNS. Regarding the return on investment, 50% SE replacement has the highest return of 98.62% compared to 100% CHNS, with 49.87% only for a projected six cropping cycles. Hence, a 50% replacement of CHNS with SE from its recommended rate can be suggested for more profitable production of green leaf lettuce under a hydroponic system. [ABSTRACT FROM AUTHOR]

Influxes of sargassos are responsible for economic and environmental disasters in areas where they bloom, especially in regions whose main income relies on tourism and with limited capacity for sanitation and public health response. A promising way of valorization would be to convert this incredible biomass into tools to fight the deadly vector mosquito Aedes aegypti. In the present study, we generated hydrolates and aqueous extracts from three main Sargassum morphotypes identified in Guadeloupe (French West Indies): Sargassum natans VIII, Sargassum natans I and Sargassum fluitans. We conducted a chemical characterization and a holistic evaluation of their potential to induce toxic and behavioral effects in Ae. aegypti. Despite the low insecticidal potential observed for all the extracts, we found that S. natans VIII and S. fluitans hydrolates deterred oviposition, induced contact irritancy and stimulated blood feeding behavior in host seeking Ae. aegypti females, while aqueous extracts from S. natans I and S. fluitans deterred both blood feeding behavior and oviposition. Chemical characterization evidenced the presence of phenylpropanoid, polyphenols, amino acids and esters. Thus, Sargassum spp. aqueous extracts and hydrolates could be used to manipulate Ae. aegypti behavior and be valorized as control tools against this mosquito. [ABSTRACT FROM AUTHOR]

In recent years, pelagic Sargassum has invaded the Caribbean coasts, and anaerobic digestion has been proposed as a sustainable management option. However, the complex composition of these macroalgae acts as a barrier to microbial degradation, thereby limiting methane production. Microbial adaptation is a promising strategy to improve substrate utilization and stress tolerance. This study aimed to investigate the adaptation of a microbial consortium to enhance methane production from the pelagic Sargassum. Microbial adaptation was performed in a fed-batch mode for 100 days by progressive feeding of Sargassum. The evolution of the microbial community was analyzed by high-throughput sequencing of 16S rRNA amplicons. Additionally, 16S rRNA data were used to predict functional profiles using the iVikodak platform. The results showed that, after adaptation, the consortium was dominated by the bacterial phyla Bacteroidota, Firmicutes, and Atribacterota, as well as methanogens of the families Methanotrichaceae and Methanoregulaceae. The abundance of predicted genes related to different metabolic functions was affected during the adaptation stage when Sargassum concentration was increased. At the end of the adaptation stage, the abundance of the predicted genes increased again. The adapted microbial consortium demonstrated a 60% increase in both biomethane potential and biodegradability index. This work offers valuable insights into the development of treatment technologies and the effective management of pelagic Sargassum in coastal regions, emphasizing the importance of microbial adaptation in this context. [ABSTRACT FROM AUTHOR]

Most deep-ocean life relies on organic carbon from the surface ocean. While settling primary production rapidly attenuates in the water column, pulses of organic material can be quickly transported to depth in the form of food falls. One example of fresh material that can reach great depths across the tropical Atlantic Ocean and Caribbean Sea is the pelagic macroalgae Sargassum. However, little is known about the deep-ocean organisms able to use this food source. Here, we encountered the isopod Bathyopsurus nybelini at depths 5002–6288 m in the Puerto Rico Trench and Mid-Cayman Spreading Center using the Deep Submergence Vehicle Alvin. In most of the 32 observations, the isopods carried fronds of Sargassum. Through an integrative suite of morphological, DNA sequencing, and microbiological approaches, we show that this species is adapted to feed on Sargassum by using a specialized swimming stroke, having serrated and grinding mouthparts, and containing a gut microbiome that provides a dietary contribution through the degradation of macroalgal polysaccharides and fixing nitrogen. The isopod's physiological, morphological, and ecological adaptations demonstrate that vertical deposition of Sargassum is a direct trophic link between the surface and deep ocean and that some deep-sea organisms are poised to use this material. [ABSTRACT FROM AUTHOR]

Sargassum is described as possessing biological metabolites that exhibit a range of activities including immuno-modulatory, analgesic, antioxidant, neuroprotective, anti-bacterial, antiinflammatory, anti-tumor, and anti-viral activities to discover the antibacterial activity of the secondary metabolites of Sargassum vulgare by in silico approach. Samples were collected from the coastal zone of Boushehr, Persian Gulf. Species identification was performed by morphological and molecular analyses. The ethanolic and methanolic extracts of S. vulgare were subjected to GC-MS. The metabolites identified through GC-MS analysis were selected as ligands for interaction with the protein receptor in a molecular docking study using the PyRx software. Subsequently, nine ligands exhibiting high bind affinity and favorable interactions were assessed for their physicochemical, pharmacokinetic, and drug-likeness properties via the SwissADME web server. GC-MS analysis identified the presence total of 28 secondary metabolites comprising 16 ethanolic and 12 methanolic compounds. A docking study of these bioactive compounds showed their binding affinity and reactivity with the exotoxin A of Pseudomonas aeruginosa. Based on the ADME results, two compounds, Dioctyl Benzene-1, 2-Dicarboxylate, and Bis (6-Methylheptyl) Benzene-1, 2-Dicarboxylate, exhibited superior properties for drug targeting. The results suggested that the majority of compounds derived from S. vulgare extracts were effectively docked at the active site of exotoxin A of P.aeruginosa, Therefore, S. vulgare may serve as a sources of phytochemical metabolites with antibacterial properties, potentially mitigating the adverse effects associated with synthetic drugs. Further exploration into clinical applications is warranted. [ABSTRACT FROM AUTHOR]

Norovirus (NoV) is the main pathogen that causes acute gastroenteritis and brings a heavy socio-economic burden worldwide. In this study, five polysaccharide fractions, labeled pSFP-1-5, were isolated and purified from Sargassum fusiforme (S. fusiforme). In vitro experiments demonstrated that pSFP-5 significantly prevented the binding of type A, B and H histo-blood group antigens (HBGAs) to NoV GII.4 virus-like particles (NoV GII.4 VLPs). In addition, in vivo experiments revealed that pSFP-5 was effective in reducing the accumulation of NoV in oysters, indicating that pSFP-5 could reduce the risk of NoV infection from oyster consumption. The results of transmission electron microscopy showed that the appearance of NoV GII.4 VLPs changed after pSFP-5 treatment, indicating that pSFP-5 may achieve antiviral ability by altering the morphological structure of the viral particles so that they could not bind to HBGAs. The results of the present study indicate that pSFP-5 may be an effective anti-NoV substance and can be used as a potential anti-NoV drug component. [ABSTRACT FROM AUTHOR]

The specific identification of three major morphotypes of the tropical holopelagic Sargassum species causing massive strandings on the African and Caribbean coastlines was attempted by morphological characterisation as well as quantitative and qualitative analyses of several metabolites. Of the 25 morphological variables studied on 208 samples from the North Atlantic Ocean, 22 were used to establish a dichotomous identification key, allowing without any doubt the identification of each morphotype based on their morphological criteria alone. We also attempted to differentiate morphotypes using chemical fingerprintings (HR-MAS NMR) and markers by analysing pigment level and composition using High Pressure Liquid Chromatography, terpene profiles by Thin Layer Chromatography, phenolic compound levels by the Folin-Ciocalteu assay and structures by 2D Nuclear Magnetic Resonance spectroscopy, and fatty acid composition by Gas Chromatography. While pigment level and composition, terpene profiles, and phenolic contents were not discriminating, quantification of eight fatty acids enabled the differentiation of the three morphotypes. Furthermore, phlorotannin purification permitted their structural characterisation allowing discrimination between the three morphotypes. Our study highlights the potential of the free fatty acid profile and phlorotannin structure as good chemomarkers in order to discriminate between the three morphotypes of holopelagic Sargassum. [ABSTRACT FROM AUTHOR]

For over a decade, numerous Greater Caribbean and Western African coasts have received enormous masses of holopelagic Sargassum spp. (sargasso). A promising use of this beached biomass as a feed ingredient in the animal industry is restricted by its high arsenic (As) content. This proof of concept aimed to demonstrate that simple, low-cost processes involving hot water (either fresh or seawater) and/or citric acid can remove arsenic from the sargasso. Sargasso collected from a Mexican Caribbean beach in December 2023 had a total arsenic level of 62.2 mg/kg, which decreased to 7.2 mg/kg after treatment with hot freshwater (90 °C for 15 min), and then further decreased to 0.8 mg/kg when followed up with a citric acid treatment. Sargasso collected in March 2024 had total arsenic of 89 mg/kg, which was lowered to 2.6 mg/kg by applying hot freshwater and citric acid sequentially. Employing only citric acid reduced the arsenic concentration to 8.0 mg/kg, while treating the sargasso only with hot seawater reduced the As level to 10.1 mg/kg. Thus, simply using hot water, either fresh or seawater, lowered the arsenic levels to acceptable levels for the animal feeding sector. These straightforward and potentially cost-effective methods may transform the restraint of high arsenic contents into a valuable opportunity to use these seaweeds as animal feed. [ABSTRACT FROM AUTHOR]

This study investigates the temporal trends and correlations between Saharan dust mass concentration densities (DMCD) and Sargassum concentrations (SCT) in the tropical North Atlantic. Average DMCD data for June, July, and August from 1980 to 2022, alongside SCT data for the same months from 2012 to 2022, were analyzed using Mann–Kendall tests for trends and lagged regression models to assess whether higher Saharan dust levels correlate with Sargassum outbreaks in the region. A comprehensive analysis reveals a significant upward trend in Saharan dust quantities over the study period, with the summer months of June, July, and August exhibiting consistent increases. Notably, 2018 and 2020 recorded the highest mean DMCD levels, with June showing the most significant increasing trend, peaking in 2019. These findings are consistent with previous studies indicating a continuous elevation in Saharan dust concentrations in the tropical atmosphere of the North Atlantic. Simultaneously, Sargassum concentrations also show a notable increasing trend, particularly in 2018, which experienced both peak SCT and elevated DMCD levels. Mann–Kendall tests confirm statistically significant upward trends in both Saharan dust and Sargassum concentrations. Simple linear regression and lagged regression analyses reveal positive correlations between DMCD and SCT, highlighting a temporal component with stronger associations observed in July and the overall June–July–August (JJA) period. These results underscore the potential contribution of elevated Saharan dust concentrations to the recent surge in Sargassum outbreaks in the tropical North Atlantic. Furthermore, the results from forward stepwise regression (FSR) models indicate that DMCD and chlorophyll (CHLO) are the most critical predictors of SCT for the summer months, while sea surface temperature (SST) was not a significant predictor. These findings emphasize the importance of monitoring Saharan dust and chlorophyll trends in the Eastern Caribbean, as both factors are essential for improving Sargassum modeling and prediction in the region. This study provides valuable insights into the climatic factors influencing marine ecosystems and highlights the need for integrated environmental monitoring to manage the impacts on coastal economies. [ABSTRACT FROM AUTHOR]

The Martinique island, located in the Caribbean Sea, is subject to the stranding of Sargassum algae, which decompose and release toxic gases, such as hydrogen sulfide or ammonia. This study aims to investigate the atmospheric corrosion of zinc in these conditions. For this purpose, three sites in Martinique more or less impacted by Sargassum algae stranding were selected. Mass loss results after 1‐year exposure range from 1.9 µm for the site least impacted to 45.3 µm for the site most affected by Sargassum algae. This high value proves that the presence of Sargassum algae caused significant zinc degradation. The morphological structures and properties of the corrosion products obtained at the impacted and non‐impacted sites differ significantly. In the absence of Sargassum algae, "classical" corrosion products based on hydrozincite, simonkoleite, gordaite, and zinc hydroxylsulfate are observed. In the area close to the Sargassum seaweed stranding, the presence of elemental sulfur products, zinc hydroxylsulfate, and sphalerite is reported. [ABSTRACT FROM AUTHOR]

The valorization of massive strandings of holopelagic Sargassum spp. is strongly limited by high levels of inorganic arsenic (Asi) that are potentially above the limit of current regulations. Monitoring Asi in algal biomass is currently achieved using standard chromatographic separation followed by spectroscopic detection. Here, we propose an alternative simpler procedure based on the extraction of Asi from the freeze-dried algal powder in deionized water and the electroanalytical detection of the diluted extract at a gold-microwire electrode. The protocol was optimized both in terms of extraction (powder/water ratio, extraction time, temperature) and electrolyte used for the voltammetric detection. Two electrolytes were tested: one composed of citric acid, sulfamic acid and KCl (pH 2.0) and another composed of an acetate buffer (pH 4.7) and NaCl. We demonstrate here that Asi determination is possible with the first electrolyte but it is necessary to deal with a relative unstable signal. Measurement of Asi was best achieved with the second electrolyte (acetate buffer and NaCl) with the following optimized electrochemical conditions: deposition potential of −1.2 V, deposition time of 30 seconds and linear scan voltammetry. Voltammetric results were then compared to a reference method (HPLC-ICP-MS) using different morphotypes of holopelagic Sargassum spp. (S. natans VIII, S. natans I and S. fluitans III), using commercial extracts of brown seaweeds and using a Hijiki certified reference material. Very good agreement was obtained between our novel method and HPLC-ICP-MS. Both methods show that inorganic arsenic is almost entirely present as As(V) in Sargassum spp. extracts. [ABSTRACT FROM AUTHOR]

This research project aimed to address the growing concern about methane emissions from seaweed by developing a Convolutional Neural Network (CNN) model capable of accurately predicting these emissions. The study used PANDAS to read and analyze the dataset, incorporating statistical measures like mean, median, and standard deviation to understand the dataset. The CNN model was trained using the ReLU activation function and mean absolute error as the loss function. The model performance was evaluated through MAPE graphs, comparing the mean absolute percentage error (MAPE) between training and validation sets and between true and predicted emissions, and analyzing trends in yearly greenhouse gas emissions. The results demonstrated that the CNN model achieved a high level of accuracy in predicting methane emissions, with a low MAPE between the expected and actual values. This approach should enhance our understanding of methane emissions from Sargassum, contributing to more accurate environmental impact assessments and effective mitigation strategies. [ABSTRACT FROM AUTHOR]

This research project aimed to address the growing concern about methane emissions from seaweed by developing a Convolutional Neural Network (CNN) model capable of accurately predicting these emissions. The study used PANDAS to read and analyze the dataset, incorporating statistical measures like mean, median, and standard deviation to understand the dataset. The CNN model was trained using the ReLU activation function and mean absolute error as the loss function. The model performance was evaluated through MAPE graphs, comparing the mean absolute percentage error (MAPE) between training and validation sets and between true and predicted emissions, and analyzing trends in yearly greenhouse gas emissions. The results demonstrated that the CNN model achieved a high level of accuracy in predicting methane emissions, with a low MAPE between the expected and actual values. This approach should enhance our understanding of methane emissions from Sargassum, contributing to more accurate environmental impact assessments and effective mitigation strategies.

This study investigates the temporal trends and correlations between Saharan dust mass concentration densities (DMCD) and Sargassum concentrations (SCT) in the tropical North Atlantic. Average DMCD data for June, July, and August from 1980 to 2022, alongside SCT data for the same months from 2012 to 2022, were analyzed using Mann–Kendall tests for trends and lagged regression models to assess whether higher Saharan dust levels correlate with Sargassum outbreaks in the region. A comprehensive analysis reveals a significant upward trend in Saharan dust quantities over the study period, with the summer months of June, July, and August exhibiting consistent increases. Notably, 2018 and 2020 recorded the highest mean DMCD levels, with June showing the most significant increasing trend, peaking in 2019. These findings are consistent with previous studies indicating a continuous elevation in Saharan dust concentrations in the tropical atmosphere of the North Atlantic. Simultaneously, Sargassum concentrations also show a notable increasing trend, particularly in 2018, which experienced both peak SCT and elevated DMCD levels. Mann–Kendall tests confirm statistically significant upward trends in both Saharan dust and Sargassum concentrations. Simple linear regression and lagged regression analyses reveal positive correlations between DMCD and SCT, highlighting a temporal component with stronger associations observed in July and the overall June–July–August (JJA) period. These results underscore the potential contribution of elevated Saharan dust concentrations to the recent surge in Sargassum outbreaks in the tropical North Atlantic. Furthermore, the results from forward stepwise regression (FSR) models indicate that DMCD and chlorophyll (CHLO) are the most critical predictors of SCT for the summer months, while sea surface temperature (SST) was not a significant predictor. These findings emphasize the importance of monitoring Saharan dust and chlorophyll trends in the Eastern Caribbean, as both factors are essential for improving Sargassum modeling and prediction in the region. This study provides valuable insights into the climatic factors influencing marine ecosystems and highlights the need for integrated environmental monitoring to manage the impacts on coastal economies.

Abstract Influxes of sargassos are responsible for economic and environmental disasters in areas where they bloom, especially in regions whose main income relies on tourism and with limited capacity for sanitation and public health response. A promising way of valorization would be to convert this incredible biomass into tools to fight the deadly vector mosquito Aedes aegypti. In the present study, we generated hydrolates and aqueous extracts from three main Sargassum morphotypes identified in Guadeloupe (French West Indies): Sargassum natans VIII, Sargassum natans I and Sargassum fluitans. We conducted a chemical characterization and a holistic evaluation of their potential to induce toxic and behavioral effects in Ae. aegypti. Despite the low insecticidal potential observed for all the extracts, we found that S. natans VIII and S. fluitans hydrolates deterred oviposition, induced contact irritancy and stimulated blood feeding behavior in host seeking Ae. aegypti females, while aqueous extracts from S. natans I and S. fluitans deterred both blood feeding behavior and oviposition. Chemical characterization evidenced the presence of phenylpropanoid, polyphenols, amino acids and esters. Thus, Sargassum spp. aqueous extracts and hydrolates could be used to manipulate Ae. aegypti behavior and be valorized as control tools against this mosquito.

Influenza is a contagious viral infection of the respiratory tract, affecting nearly 10% of the world's population, each year. The aim of this study was to extract and identify antiviral compounds against the influenza-A virus (H1N1) from different species of Egyptian marine algae. Three samples of marine macroalgae species were extracted and the antiviral activity of the extracts were tested on Madin Darby Canine Kidney cells. The bioactive compounds present in the most active fractions were identified using gas chromatography-mass spectrometry (GC-MS), then the binding potentials of the identified compounds were examined towards neuraminidase (NA) of the influenza-A virus using molecular docking. The methanolic extract of Sargassum aquifolium showed promising in-vitro antiviral activity with a selectivity index (SI) value of 101. The GC-MS analysis showed twelve compounds and the molecular docking analysis found that tetradecanoic acid showed the strongest binding affinities towards the NA enzyme. [ABSTRACT FROM AUTHOR]

Sargassum algae, being able to proliferate without the need to be attached to a substrate, travel through the ocean generating massive stagnations on the Caribbean coasts of the continent, becoming an environmental problem. Because its composition mainly includes polysaccharides, such as cellulose and hemicellulose, these algae were used to produce nanocellulose and create hydrogels to apply to germination. This article aims to develop of nanocellulose hydrogels from Sargassum and study the effect of it adding nanocellulose hydrogels from Sargassum algae loaded with Ca-PO4- and NO3 as nutrients in the germination process. The Sargassum algae used underwent two hydrolysis processes, one basic and one acid, with which it was possible to increase the cellulose content from 25.7 ± 0.42% to 34.05 ± 0.39 after the first hydrolysis and after 90.15 ± 0.44% after the second. Size reduction to nanocellulose was performed employing an ultrasonic homogenizer sonicator. The obtained nanocellulose was characterized using infrared spectroscopy, X-ray diffraction, and transmission electron microscopy, showing that by the alkaline method, the sizes were between 135-190 nm while by the acid method, the fiber sizes were between 108-163 nm with a difference of 1.04 in the crystallinity index between the two hydrolyses. With the nanocellulose, hydrogels were formed using 5%, 10%, and 15% borax as crosslinking agents. Drying curves and scanning electron microscopy were performed on the hydrogels. Nutrients Ca-PO4-NO3 were added to the hydrogel and their release in water was studied through Ultraviolet-Visible spectrophotometry, with which it was decided to use the hydrogel containing 10% borax in the germination study. The effect of the hydrogel loaded with nutrients on the germination of bean and linseed seeds employing a complete factorial design 23. Obtaining results that the nutrient with the greatest influence on germination was nitrogen while the nutrient with the least favorable results was the match. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis (OA) presents a formidable challenge, characterized by as-yet-unclear mechanical intricacies within cartilage and the dysregulation of bone homeostasis. Our preliminary data revealed the encouraging potential of a Sargassum polysaccharide (SP), in promoting chondrogenesis. The aim of our study is to comprehensively assess the therapeutic effects of SP on OA models and further elucidate its potential mechanism. Methods: The protective effects of SP were initially evaluated in an inflammation-induced human chondrocyte (C28) cell model. CCK-8 assays, Alcian blue staining, RT-qPCR and Western blotting were used to verify the chondrogenesis of SP in vitro. To assess the efficacy of SP in vivo, surgically induced medial meniscus destabilization (DMM) OA rats underwent an 8-week SP treatment. The therapeutic effects of SP in OA rats were comprehensively evaluated using X-ray imaging, micro-computed tomography (μ-CT), histopathological analysis, as well as immunohistochemical and immunofluorescent staining. Following these assessments, we delved into the potential signaling pathways of SP in inflammatory chondrocytes utilizing RNA-seq analysis. Validation of these findings was conducted through RT-qPCR and western blotting techniques. Results: SP significantly enhance the viability of C28 chondrocytes, and increased the secretion of acidic glycoproteins. Moreover, SP stimulated the expression of chondrogenic genes (Aggrecan, Sox9, Col2a1) and facilitated the synthesis of Collagen II protein in C28 inflammatory chondrocytes. In vivo experiments revealed that SP markedly ameliorated knee joint stenosis, alleviated bone and cartilage injuries, and reduced the histopathological scores in the OA rats. μ-CT analysis confirmed that SP lessened bone impairments in the medial femoral condyle and the subchondral bone of the tibial plateau, significantly improving the microarchitectural parameters of the subchondral bone. Histopathological analyses indicated that SP notably enhanced cartilage quality on the surface of the tibial plateau, leading to increased cartilage thickness and area. Immunohistochemistry staining and immunofluorescence staining corroborated these findings by showing a significant promotion of Collagen II expression in OA joints treated with SP. RNA-seq analysis suggest that SP's effects were mediated through the regulation of the ITGβ1-PI3K-AKT signaling axis, thereby stimulating chondrogenesis. Verification through RT-qPCR and Western blot analyses confirmed that SP significantly upregulated the expression of ITGβ1, p110δ, AKT1, ACAN, and Col2a1. Notably, knock-down of ITGβ1 using siRNA in C28 chondrocytes inhibited the expression of ITGβ1, p110δ, AKT1, and ACAN. However, these inhibitory effects were not completely reversed by supplemental SP intervention. Conclusions: In summary, our findings reveal that SP significantly enhances chondrogenesis both in vitro and in vivo, alleviating OA progression both in bone and cartilage. The observed beneficial effects are intricately linked to the activation of the ITGβ1-PI3K-AKT signaling axis. The translational potential of this article: Our research marks the first instance unveiling the advantageous effects and underlying mechanisms of SP in OA treatment. With its clinical prospects, SP presents compelling new evidence for the advancement of a next-generation polysaccharide drug for OA therapy.

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. [ABSTRACT FROM AUTHOR]

The species of the brown macroalgal genus Sargassum are distributed globally and contain many bioactive compounds. In this study, ultrasound‐assisted extraction (UAE) was applied to obtain phenolic compounds with strong antioxidant activity from Sargassum carpophyllum collected along the coastline of Weizhou Island in the South China Sea. The influence of different variables such as the solid–liquid ratio (1:5–1:30 g · mL−1), ultrasonic power (160–280 W), duty circle ratio (DCR, 1/3–1/1), and ethanol concentration (30% to ~90%) were studied using a single factor design. The extraction kinetics were investigated using the Peleg model and second‐order kinetics model, and the second‐order model described the extraction procedure better than the Peleg model. Total phenol content (TPC) values of 3.316, 2.964, 2.741, and 3.665 mg phloroglucinol (PHG) · g−1 algae were achieved at a higher solid–liquid ratio (1:30 g · mL−1), higher ultrasonic power (280 W), a higher DCR (1/1), and a moderate ethanol concentration (50%), respectively. However, a slightly different result was observed in the extract obtained, with total phenol contents (TPCextract) of 52.99, 65.00, 46.22, and 55.10 mg PHG · g−1 extract and DPPH radical scavenging activity (IC50) of 0.096, 0.066, 0.131, and 0.136 mg extract · mL−1 observed at 50% ethanol, 1:5 g m· mL−1, 2/3 DCR, and 200 W respectively. All variables studied influenced the extraction kinetics by altering the extraction rate and the TPC at equilibrium. As for the bioactivities in the extract, a larger solid–liquid ratio and greater ultrasonic power may not contribute because of their ability to extract non‐phenolic components simultaneously, leading to reduced overall bioactivities. The results of the present study provide essential information for future UAE process design and optimization for extracting phenolics from S. carpophyllum through mathematical modeling and could be regarded as important reference for obtaining value‐added products from other macroalgae species. [ABSTRACT FROM AUTHOR]

Herpes viruses (HSV) are among the most common viruses that infect humans. They cause blisters and inflammation of the oral and genital mucosa as well as severe symptoms such as blindness, hearing impairment and fatal encephalitis. Although acyclovir (ACV) and its derivatives are highly effective in treating recurrent lytic infections, the emergence of resistant strains remains a concern. In this study, the in vitro anti-herpetic activity of a hydroalcoholic extract obtained from the brown seaweed Sargassum fluitans, collected from strandings in Cuba, was evaluated. The hydroalcoholic extract was not cytotoxic in Vero cells (CC50 >5000 µg mL-1) and inhibited replication of HSV-1 (ACV-susceptible and -resistant) and HSV-2 (ACV-resistant) strains with EC50 of 271.66, 403.62 and 14.99 µg mL-1 respectively. In addition, first studies about mechanism of action were evaluated with ACV-sensitive HSV-1 model. The extract showed strong inhibition when pre-incubated with the virus and when the extract and virus were added simultaneously on the cells. The protection of Vero cells during the post-infection assay was very effective up to 1 h. A high resolution UPLC/MS-MS analysis detected 139 compounds, of which 44 were identified. In silico analysis was performed to determine the putative interaction sites of two flavones of interest identified in the extract with the viral glycoprotein D (gD). Molecular docking analysis revealed that takakin and tectorigenin mainly interact with the gD protein active center through hydrophobic interactions (Leu44, Pro50, Thr174, Lys169, Tyr208, Gln209) while hydrogen bonding interactions are less abundant (Ser43, Asp46, Lys169, Tyr208). This research represents a contribution to the valorization of S. fluitans as a source of anti-herpetic compounds in the context of recurrent and abundant seaweed strandings. [ABSTRACT FROM AUTHOR]

Sargassum is a genus of brown algae that causes a major impact to marine ecosystems. Although accumulation of this invasive seaweed is considered an environmental problem, Sargassum can also be resource of valuable molecules such as alginates. Alginates are polysaccharides extracted from the cell walls of brown seaweeds with multiple applications in food, cosmetics, pharmaceuticals, and biotechnology. In this study, we explored four different extraction protocols to isolate alginates from Sargassum from the archipelago of Guadeloupe. H-NMR, FTIR, and SEM were carried out to characterize isolated samples and describe their chemical and morphological properties. Antioxidant capacity of the isolated alginates was tested in the sample. FRAP assay showed free radical scavenging activity, and cell viability assay showed that alginates keep protective capacity against oxidative stress in cell cultures. In sum, the isolation methods used in this study are effective extractive methods to obtain alginates from Sargassum, which highlight this seaweed as a potential source of bioactive compounds that may be exploited for industrial and biomedical purposes. [ABSTRACT FROM AUTHOR]

The present study on the brown seaweeds Sargassum muticum focused on the application of dehydration by pressing or pulsed electric fields (PEF) pretreatment before three drying processes, namely freeze-drying, air impingement drying, and natural convection in an oven. Both pretreatments permitted to reduce significantly the initial moisture of the seaweeds with a reduction up to 50 %. The structural modifications induced by these pretreatments had a direct impact on the mechanisms of moisture retention and distribution within the seaweeds, which consequently exerted an influence on drying kinetics. The apparent moisture diffusivity for freeze-drying was significantly improved by PEF passing from 2.98 10−9 m2 s−1 to 3.62 10−9 m2 s−1 after a total disintegration. Concerning oven drying by natural convection, a dehydration by pressing will be preferred because the drying time to reach 0.45 kg kg−1 in dry basis was reduced by 61 min with this pretreatment. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Immune inflammation is one of the main factors in the pathogenesis of depression. It is an effective and active way to find more safe and effective anti-inflammatory depressant drugs from plant drugs. The purpose of this study is to explore the potential of marine plant Sargassum pallidum (Turn).C.Ag. (Haihaozi, HHZ) in the prevention and treatment of depression and to explain the related mechanism. Phytochemical analysis showed that alkaloids, terpenes, and organic acids are the main constituents. In vitro and in vivo activity studies showed the anti-neuroinflammatory and antidepressant effect of Sargassum pallidum, furthermore, confirmed that 7-Hydroxycoumarin, Scoparone, and Kaurenoic Acid are important plant metabolites in Sargasum pallidum for antineuroinflammation. Mechanism exploration showed that inhibition of ERK1/2/p38 inflammatory signaling pathway contributing to the antidepressant effect of Sargassum pallidum in reducing intestinal inflammatory levels. This study confirmed the value of Sargassum pallidum and its rich plant metabolites in anti-inflammatory depression, providing a new choice for the follow-up research and development of antidepressant drugs. [ABSTRACT FROM AUTHOR]

Global coral reef degradation has precipitated phase shifts toward macroalgal-dominated communities. Despite the negative repercussions for reefscapes, higher abundances of primary producers have the potential to positively impact the physicochemical environment and mitigate negative impacts of ocean acidification (OA). In this study, we investigated the influence of macroalgal (cf. Sargassum vulgare) density on coral (Acropora millepora and A. hemprichii) calcification rates under current and future OA conditions. Corals were resistant to OA up to ~ 1100 µatm, with no changes in calcification rates. However, the presence of (low and high density) algae reduced calcification rates by ~ 41.8%, suggesting either a chemical defense response due to algal metabolites or potential physical impacts from shading or abrasion. Documented beneficial buffering effects of macroalgae in OA may also elicit negative impacts on coral calcification, suggesting further work is needed to elucidate how species interactions influence responses to projected climate change. [ABSTRACT FROM AUTHOR]

The self-assembled monolayers (SAMs) process is one of the techniques used for the production of ultra-thin layers. The present work is therefore devoted to the study of the inhibition of zinc corrosion in a marine environment rich in H2S by SAMs based on Sargassum fluitans III. The protective effect of crude extracts of Sargassum fluitans on the surface of zinc using the SAMs process was evaluated by gravimetry and impedance on two different sites after three months of exposure. The formation of SAMs was characterized by FTIR, and the corrosion products formed on the surfaces were analyzed by XRD. The results obtained show that SAMs based on Sargassum fluitans III effectively inhibit zinc corrosion. [ABSTRACT FROM AUTHOR]

Sargassum horneri (S. horneri), a brown seaweed excessively proliferating along Asian coastlines, are damaging marine ecosystems. Thus, this study aimed to enhance nutritional value of S. horneri through lactic acid bacteria fermentation to increase S. horneri utilization as a functional food supplement, and consequently resolve coastal S. horneri accumulation. S. horneri supplemented fermentation was most effective with Lactiplantibacillus pentosus SH803, thus this product (F-SHWE) was used for further in vitro studies. F-SHWE normalized expressions of oxidative stress related genes NF-κB, p53, BAX, cytochrome C, caspase 9, and caspase 3, while non-fermented S. horneri (SHWE) did not, in a H2O2-induced HT-29 cell model. Moreover, in an LPS-induced HT-29 cell model, F-SHWE repaired expressions of inflammation marker genes ZO1, IL1β, IFNγ more effectively than SHWE. For further functional assessment, F-SHWE was also treated in 3T3-L1 adipocytes. As a result, F-SHWE decreased lipid accumulation, along with gene expression of adipogenesis markers PPARγ, C/EBPα, C/EBPβ, aP2, and Lpl; lipogenesis markers Lep, Akt, SREBP1, Acc, Fas; inflammation markers IFN-γ and NF-κB. Notably, gene expression of C/EBPβ, IFN-γ and NF-κB were suppressed only by F-SHWE, suggesting the enhancing effect of fermentation on obesity-related properties. Compositional analysis attributed the protective effects of F-SHWE to acetate, an organic acid significantly higher in F-SHWE than SHWE. Therefore, F-SHWE is a novel potential anti-obesity agent, providing a strategy to reduce excess S. horneri populations along marine ecosystems. [ABSTRACT FROM AUTHOR]

Understanding the bioactive components and dietary fiber from various seaweed species is crucial as a scientific basis, especially their use in developing functional food products. This research aimed to determine the bioactive components and dietary fiber of Gracilariopsis longissima, Ulva lactuca, and Sargassum aquifolium, which grow in Garut Coast, Indonesia. Apart from water content, significant differences were observed in each seaweed's proximate composition (ash, lipid, crude fiber and protein). In addition, the antioxidant activity (7.74-8.91% RSA), total phenolics (36.85-87.37mg GAE/ 100g) and flavonoid content (7.81-17.58mg QE/ 100g) of each seaweed were significantly different. In particular, Sargassum aquifolium contains significantly higher total dietary fiber (66.04%), soluble dietary fiber (26.11%) and insoluble dietary fiber (39.93%) than Gracilariopsis longissima and Ulva lactuca. In conclusion, each seaweed species growing in the Garut Coast (Indonesia) has significantly different bioactive components and dietary fiber. [ABSTRACT FROM AUTHOR]

The experiment aims to investigate antibacterial activity of Sargassum polyphenols on Esch⁃ erichia coli (E. coli). Ethanol extraction and dextran gel column chromatography were used to extract and purify phlorotannins from Sargassum, the inhibitory effect of phlorotannins on E. coli was investigated by measuring the inhibition level, minimum inhibitory concentration and minimum bactericidal concentra‐ tion of phlorotannins on E. coli, as well as the influence on its proliferation curve and biofilm formation. The results show that the content of extracted and purified polyphenols was 848 mg/g. The minimum in‐ hibitory concentration (MIC) for E. coli was 4 mg/mL and the minimum bactericidal concentration (MBC) was 16 mg/mL. Compared to the control group, the growth of E. coli treated with the 2 MIC and 1 MIC phlorotannins was significantly inhibited. The antibacterial effect of 1/2 MIC phlorotannins was reduced, and E. coli growth was completely inhibited in 4 MIC phlorotannins. All groups supplemented with phlo‐ rotannins had a significant inhibition of bacterial proliferation within 2 to 8 hours (P<0.01). Concentra‐ tions of phlorotannins in the range of 4 to 16 mg/mL were able to significantly reduce biofilm formation (P<0.05). In conclusion, the phlorotannins have a clear inhibitory effect on E. coli. [ABSTRACT FROM AUTHOR]

Copyright of Avances is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The movement and biomass fluctuations of sargassum across the Tropical Atlantic have profound implications when influxes reach the Eastern Caribbean. These influxes have cross-cutting impacts across ecological, economic, and social systems. The objective of this work is to quantify sargassum biomass accumulation in the Eastern Caribbean, accounting for the spatial variability in sea surface temperature and morphotype diversity. A parallel implementation of a climatological drifter-based model was used to simulate advection of sargassum across the model domain. After determining the trajectory of virtual sargassum particles, Monte Carlo simulations using 1000 realizations were run to quantify biomass accumulations along these tracks. For simulations with a single morphotype, the biomass accumulation as predicted by the model effectively reproduced the seasonal distributions of sargassum for the simulated period (May 2017 to August 2017). The model closely approximated an observed increase during the period from May to July 2017, followed by a subsequent decline in sargassum abundance. A major factor that led to the discrepancy between the simulated and observed biomass accumulation is the occlusion of the optical satellite signal from cloud cover, which led to underestimates of sargassum abundance. The mean maximum growth rate required to reproduce the observed sargassum biomass was 0.05 day−1, which is consistent with other published experimental and computational studies that have reported similar growth rates for sargassum populations under comparable environmental conditions. An innovative aspect of this study was the investigation of the biomass dynamics of the three dominant morphotypes found in the study area. The results from these simulations show that the accumulation of the fastest growing morphotype, Sargassum fluitans var. fluitans, closely approximates the profiles of the overall prediction with a single morphotype. [ABSTRACT FROM AUTHOR]

In recent years, golden tides caused by floating Sargassum have induced severe ecological disasters globally. Eutrophication is a significant factor contributing to the massive spread of Sargassum golden tides. Furthermore, the thalli of Sargassum that float on the ocean surface are subjected to more ultraviolet radiation (UVR). The coupled impact of eutrophication and UVR on the photosynthetic physiology of golden tide species remains unclear. In this study, the thalli of Sargassum horneri, known to cause golden tide, were cultured and acclimated to three distinct nitrogen (N) conditions (natural seawater, NSW; NH4 +-N enrichment; and NO3 -N enrichment) for 6 days. Subsequently, the thalli were exposed to two different radiation treatments (photosynthetically active radiation (150 W m-2), PAR, 400-700 nm; PAR (150 W m-2) + UVR (28 W m-2), 280-700 nm) for 120 min, to investigate the photosynthetic effects of UVR and N on this alga. The findings demonstrated that exposure to UVR impeded the photosynthetic capacity of S. horneri, as evidenced by a decrease in the maximum photochemical quantum yield (Fv/Fm), photosynthetic efficiency (a) and chlorophyll content. Under diverse Nenrichment conditions, the alga tended to adopt various strategies to mitigate the adverse effects of UVR. NH4 +-enrichment dissipated excess UVR energy through a greater increase in non-photochemical quenching (NPQ). While NO3 - enrichment protected alga by enhancing N assimilation (higher nitrate reductase activity (NRA) and soluble protein content), and maintained a stable energy captured per unit reaction center for electron transfer (ET0/RC) and a higher net photosynthetic rate. Although different N enrichments could not completely offset the damage caused by UV radiation, they secured the photoprotective ability of S. horneri in several ways. [ABSTRACT FROM AUTHOR]

Most canopy-forming macroalgae have disappeared from temperate reefs in southern Japan, one of the ocean warming hotspots, but Sargassum nipponicum is surviving in this region. As this species' annual shoots emerge from holdfasts during summer, both plant components may be highly tolerant to warm and nutrient-poor conditions in this season. The present study examined the effects of temperature and nutrient conditions on holdfast growth, shoot emergence from holdfasts, and shoot growth in S. nipponicum samples collected in Tanegashima Island, southern Japan. The summer temperature in this region (30 °C) allowed holdfast growth and shoot emergence but inhibited shoot growth. Nutrient-poor conditions had limited effects on the first two parameters but suppressed shoot growth. These results suggested that during warm summers and under nutrient-poor conditions in southern Japan, shoots can emerge from S. nipponicum holdfasts but cannot further grow. Additionally, nutrient loading from a nearby river was higher at the only site dominated by S. nipponicum, than at the other sites where this species was absent on Tanegashima Island. This was observed especially between autumn and winter, implying that such a nutrient-rich environment may contribute to shoot growth in S. nipponicum and to the persistence of its population in the area. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Atopic dermatitis is a chronic complex inflammatory skin disorder that requires sustainable treatment methods due to the limited efficacy of conventional therapies. Sargassum serratifolium, an algal species with diverse bioactive substances, is investigated in this study for its potential benefits as a therapeutic agent for atopic dermatitis. RNA sequencing of LPS-stimulated macrophages treated with ethanolic extract of Sargassum serratifolium (ESS) revealed its ability to inhibit a broad range of inflammation-related signaling, which was proven in RAW 264.7 and HaCaT cells. In DNCB-induced BALB/c or HR-1 mice, ESS treatment improved symptoms of atopic dermatitis within the skin, along with histological improvements such as reduced epidermal thickness and infiltration of mast cells. ESS showed a tendency to improve serum IgE levels and inflammation-related cytokine changes, while also improving the mRNA expression levels of Chi3l3, Ccr1, and Fcεr1a genes in the skin. Additionally, ESS compounds (sargachromanol (SCM), sargaquinoic acid (SQA), and sargahydroquinoic acid (SHQA)) mitigated inflammatory responses in LPS-treated RAW264.7 macrophages. In summary, ESS has an anti-inflammatory effect and improves atopic dermatitis, ESS may be applied as a therapeutics for atopic dermatitis. [ABSTRACT FROM AUTHOR]

The year 2021 marked a decade of holopelagic sargassum (morphotypes Sargassum natans I and VIII, and Sargassum fluitans III) stranding on the Caribbean and West African coasts. Beaching of millions of tons of sargassum negatively impacts coastal ecosystems, economies, and human health. Additionally, the La Soufrière volcano erupted in St. Vincent in April 2021, at the start of the sargassum season. We investigated potential monthly variations in morphotype abundance and biomass composition of sargassum harvested in Jamaica and assessed the influence of processing methods (shade-drying vs. frozen samples) and of volcanic ash exposure on biochemical and elemental components. S. fluitans III was the most abundant morphotype across the year. Limited monthly variations were observed for key brown algal components (phlorotannins, fucoxanthin, and alginate). Shade-drying did not significantly alter the contents of proteins but affected levels of phlorotannins, fucoxanthin, mannitol, and alginate. Simulation of sargassum and volcanic ash drift combined with age statistics suggested that sargassum potentially shared the surface layer with ash for ~50 d, approximately 100 d before stranding in Jamaica. Integrated elemental analysis of volcanic ash, ambient seawater, and sargassum biomass showed that algae harvested from August had accumulated P, Al, Fe, Mn, Zn, and Ni, probably from the ash, and contained less As. This ash fingerprint confirmed the geographical origin and drift timescale of sargassum. Since environmental conditions and processing methods influence biomass composition, efforts should continue to improve understanding, forecasting, monitoring, and valorizing sargassum, particularly as strandings of sargassum show no sign of abating. [ABSTRACT FROM AUTHOR]

The two‐toned pygmy squid (Idiosepius pygmaeus, Steenstrup, 1881) is a small, tropical cephalopod that inhabits seagrass meadows and is known to attach to blades of seagrass using a specialised adhesive organ. A global decline in seagrass habitat due to anthropogenic disturbances may threaten the species that rely on seagrass meadows for shelter, foraging and other crucial activities. It is unclear if I. pygmaeus can utilise alternative habitats in the absence of seagrass. Here, we test the effect of habitat type, material and composition type, and the presence of conspecifics on the settlement preferences of I. pygmaeus. Individuals each underwent three separate experiments: (1) testing the preference between their known habitat, Zostera muelleri subsp. Capricorni and potential substitute, Sargassum, (2) testing the preference to attach to a natural or artificial structure of similar shape and size, and (3) testing the preference of identical habitats, one with a conspecific adhered to and one without. We found that I. pygmaeus did not have a strong preference for either Zostera or Sargassum. However, a strong preference was found for attachment to the natural structure over the artificial one. There was also strong evidence for the use of conspecific cues in habitat choice, with 75% of individuals selecting the habitat that contained a conspecific. As habitat loss is the leading cause of species extinction, the knowledge of habitat preferences for I. pygmaeus is vital in order to assess their risk of population decline. The findings of this study suggest that I. pygmaeus could utilise an alternative habitat in the presence of seagrass meadow reduction, which is under threat from human activity. [ABSTRACT FROM AUTHOR]

In the present study, sulfated polysaccharides were obtained by digestion of Sargassum horneri and preparation with enzyme-assisted extraction using three food-grade enzymes, and their anti- Alzheimer's activities were investigated. The results demonstrated that the crude sulfated polysaccharides extracted using AMGSP, CSP and VSP dose-dependently (25–100 µg·mL− 1) raised the spontaneous alternating manner (%) in the Y maze experiment of mice and reduced the escape latency time in Morris maze test. AMGSP, CSP and VSP also exhibited good anti-AChE and moderate anti-BuChE activities. CSP displayed the best inhibitory efficacy against AChE. with IC50 values of 9.77 µM. And, CSP also exhibited good inhibitory selectivity of AChE over BuChE. Next, CSP of the best active crude extract was separated by the preparation type high performance liquid phase to obtain the sulphated fucooligosaccharide section: SFcup (→3-α-L-fucp(2-SO3−)-1→4-α-L-fucp(2,3-SO3−)-1→section), SFcup showed a best inhibitory efficacy against AChE with IC50 values of 4.03 µM. The kinetic research showed that SFcup inhibited AChE through dual binding sites. Moreover, the molecular docking of SFcup at the AChE active site was in accordance with the acquired pharmacological results. [ABSTRACT FROM AUTHOR]