Search Results (436)

Activated carbon (AC) and biochar (BC) are porous materials with large surface areas and widely used in environmental and industrial applications. In this study, different types of AC and BC samples were produced from Sargassum sp. by a chemical activation and pyrolysis process and compared to commercial activated carbon samples. All samples were characterized using various techniques to understand their structure and functionalities. The metal content of the samples was characterized by using an inductively coupled optical emission spectrometer (ICP-OES). A toxicity test was applied to investigate the effect of AC/BC on organisms, where Sinapis alba seed and Escherichia coli bacteria-based toxicity tests were used. The results revealed that the samples did not negatively affect these two organisms. Thus, it is safe to use them in various applications. Therefore, the samples were tested as fillers in polyurethane composites and, thus, polyurethane-AC/BC samples were prepared. The amounts of AC/BC mixed into the polyurethane formulation were 1%, 2%, and 3%. Mechanical and acoustic properties of these composites were analyzed, showing that by adding the AC/BC to the system an increase in the compression strength for all the samples was achieved. A similar effect of the AC/BC was noticed in the acoustic measurements, where adding AC/BC enhanced the sound adsorption coefficient (α) for all composite materials. Full article

This study deals with the efficacy of extracts of Sargassum natans and Sargassum fluitans, an invasive brown algae present in Guadeloupe, as novel and environmentally friendly corrosion inhibitors for iron in 1 mol L⁻¹ hydrochloric acid solutions. Six different Sargassum extracts (SE) were obtained using Soxhlet extraction with ethyl acetate, acetone, and ethanol, respectively, as solvents; cold successive maceration with chloroform and methanol, respectively; and microwave-assisted extraction with water. Subsequent electrochemical analysis showed that extracts from ethanol and ethyl acetate exhibited remarkable inhibition efficiencies of, respectively, 72.6% and 70.2%, but the better one was the extract of the cold maceration from chloroform with an inhibition efficiency of 92.0%. These findings allow us to focus on the chloroform extract (SEd) in order to see the change happening during the corrosion process via SEM and EDX analyses. Also, NMR analysis was conducted to identify the main chemicals responsible for the anticorrosion effect. The successful demonstration of the corrosion inhibitor effectiveness of extracts of Sargassum natans and fluitans suggests a potentially valuable use for this invasive biomass. These encouraging results warrant further investigation to identify and elucidate the active inhibitors in these extracts to deepen our understanding of their mechanisms for corrosion prevention and potentially expand their utility as an environmentally conscious approach to corrosion control. Full article

Cognitive impairments are frequently reported after ischemic strokes. Novel and effective treatments are required. This study aimed to develop a functional ingredient obtained from marine algae and to determine the effect of the extract on antioxidative stress, as well as neuroprotective effects, in a rat model of MCAO-induced ischemic stroke. Among the selected marine algal extracts, Sargassum polycystum displayed the highest total phenolic content and antioxidative potential, and was subsequently used to evaluate cognitive function in rat models of ischemic stroke. The S. polycystum extract, administered at doses of 100, 300, and 500 mg/kg BW, significantly improved cognitive function by enhancing cognitive performance in the Morris water maze and novel object recognition tests. Biochemical changes revealed that providing S. polycystum increased the activities of SOD, CAT, and GSH-Px by 52.48%, 50.77%, and 66.20%, respectively, and decreased the concentrations of MDA by 51.58% and S100B by 36.64% compared to the vehicle group. These findings suggest that S. polycystum extract may mitigate cognitive impairment in ischemic stroke by reducing oxidative stress and inhibiting S100B expression, thus highlighting its potential as a functional ingredient for drugs and nutraceuticals aimed at neuroprotection. Full article

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. Full article

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. Full article

Alginate lyase is an attractive biocatalyst that can specifically degrade alginate to produce oligosaccharides, showing great potential for industrial and medicinal applications. Herein, an alginate-degrading strain HB236076 was isolated from Sargassum sp. in Qionghai, Hainan, China. The low 16S rRNA gene sequence identity (<98.4%), ANI value (<71.9%), and dDDH value (<23.9%) clearly indicated that the isolate represented a potential novel species of the genus Vibrio. The genome contained two chromosomes with lengths of 3,007,948 bp and 874,895 bp, respectively, totaling 3,882,843 bp with a G+C content of 46.5%. Among 3482 genes, 3332 protein-coding genes, 116 tRNA, and 34 rRNA sequences were predicted. Analysis of the amino acid sequences showed that the strain encoded 73 carbohydrate-active enzymes (CAZymes), predicting seven PL7 (Alg1–7) and two PL17 family (Alg8, 9) alginate lyases. The extracellular alginate lyase from strain HB236076 showed the maximum activity at 50 °C and pH 7.0, with over 90% activity measured in the range of 30–60 °C and pH 6.0–10.0, exhibiting a wide range of temperature and pH activities. The enzyme also remained at more than 90% of the original activity at a wide pH range (3.0–9.0) and temperature below 50 °C for more than 2 h, demonstrating significant thermal and pH stabilities. Fe²⁺ had a good promoting effect on the alginate lyase activity at 10 mM, increasing by 3.5 times. Thin layer chromatography (TLC) and electrospray ionization mass spectrometry (ESI-MS) analyses suggested that alginate lyase in fermentation broth could catalyze sodium alginate to produce disaccharides and trisaccharides, which showed antimicrobial activity against Shigella dysenteriae, Aeromonas hydrophila, Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. This research provided extended insights into the production mechanism of alginate lyase from Vibrio sp. HB236076, which was beneficial for further application in the preparation of pH-stable and thermo-stable alginate lyase and alginate oligosaccharides. Full article

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. Full article

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. Full article

Macroalgal biomass blooms, including those causing the green and golden tides, have been rising along Chinese coasts, resulting in considerable social impacts and economic losses. To understand the links between the ongoing climate changes (ocean warming and acidification) and algal tide formation, the effects of temperature (20 and 24 °C), pCO₂ concentration (Partial Pressure of Carbon Dioxide, 410 ppm and 1000 ppm) and their interaction on the growth of Ulva prolifera and Ulva lactuca (green tide forming species), as well as Sargassum horneri (golden tide forming species) were investigated. The results indicate that the concurrent rises in temperature and pCO₂ level significantly boosted the growth and nutrient uptake rates of U. lactuca. For U. prolifera, the heightened growth and photosynthetic efficiency under higher CO₂ conditions are likely due to the increased availability of inorganic carbon. In contrast, S. horneri exhibited negligible responsiveness to the individual and combined effects of the increased temperature and CO₂ concentration. These outcomes indicate that the progressive climate changes, characterized by ocean warming and acidification, are likely to escalate the incidence of green tides caused by Ulva species, whereas they are not anticipated to precipitate golden tides. Full article

The extensive outbreak of Sargassum horneri in China has not merely imposed a severe threat to the ecological environment and human life in coastal waters but also impeded the development of waterway transportation and the local economy. Consequently, we isolated polysaccharides from S. horneri, designated as SHP, and evaluated the antioxidant activity of SHP both in vitro and in vivo by investigating the effect of SHP on H₂O₂-induced African green monkey kidney cells (Vero cells) and zebrafish. The results demonstrated that SHP can enhance the activities of superoxide dismutase, catalase, and glutathione peroxidase in zebrafish. It also effectively inhibits micro malondialdehyde and ROS levels in Vero cells and zebrafish to mitigate the oxidative damage caused by H₂O₂, thereby achieving the protective effect of SHP on Vero cells and zebrafish. In conclusion, SHP holds the potential as a natural antioxidant. SHP can be contemplated for utilization as a natural antioxidant in the biomedical, cosmetic, and food industries, thereby alleviating the environmental stress caused by S. horneri and achieving resource utilization. Full article

To investigate the ecological impacts of macroalgae in the framework of shifting global CO₂ concentrations, we conducted a study utilizing Ulva fasciata and Sargassum horneri specimens sourced from the Ma’an Archipelago in Zhejiang Province on how ocean acidification (OA) and temperature changes interact to affect the photosynthetic physiological responses of macroalgae. The results of the study showed that OA reduced the tolerance of U. fasciata to bright light at 20 °C, resulting in more pronounced photoinhibition, while 15 °C caused significant inhibition of U. fasciata, reducing its growth and photosynthetic activity, but OA alleviated the inhibition and promoted the growth of the alga to a certain extent. The tolerance of S. horneri to bright light was also reduced at 20 °C; the inhibition was relieved at 15 °C, and the OA further improved the algal growth. The Relative Growth Rate (RGR), photosynthetic pigment content, and the release of the dissolved organic carbon (DOC) of U. fasciata were mainly affected by the change in temperature; the growth of the alga and the synthesis of metabolites were more favored by 20 °C. A similar temperature dependence was observed for S. horneri, with faster growth and high metabolism at 15 °C. Our results suggest that OA reduces the tolerance of macroalgae to high light at suitable growth temperatures; however, at unsuitable growth temperatures, OA effectively mitigates this inhibitory effect and promotes algal growth. Full article

This study aimed to biosynthesize zinc oxide nanoparticles (ZnO-NPs) using extracts from various seaweeds, including Ulva lactuca, Ulva intestinalis (Chlorophyta), and Sargassum muticum (Phaeophyceae). The biosynthesized ZnO-NPs were characterized using UV spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and zeta potential analysis. Their antimicrobial activity was assessed using the disk diffusion method, revealing significant efficacy against two bacterial species (Klebsiella pneumoniae and Escherichia coli) and two fungal species (Candida albicans and Aspergillus niger). Additionally, the antioxidant potential of the ZnO-NPs was evaluated based on the total antioxidant capacity, ferric reducing antioxidant power, and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assays. The antioxidant activity of the ZnO-NPs was confirmed using the three antioxidant assays. The ZnO-NPs of U. lactuca recorded the highest antioxidant activity. The cytotoxicity of the ZnO-NPs was tested on different cell lines using the MTT assay. The ZnO-NPs of U. lactuca showed very weak cytotoxic effects on WI 38 (84.98 ± 4.6 µg/mL) and 23, and this result confirmed its safety on normal cells. The ZnO-NPs of U. lactuca showed moderate cytotoxic effects on the HepG-2 (46.66 ± 2.8 µg/mL) and MCF-7 (30.60 ± 2.1 µg/mL) cell lines. In an in vivo study, the ZnO-NPs of U. lactuca showed a decrease in tumor volume, weight, and serum malondialdehyde in experimental mice, while the total antioxidant capacity of the serum was increased. Histopathological changes in ZnO-NPs indicated a reduction in tumor size, a lower number of mitosis divisions, and a rise in apoptosis correlated with the ZnO-NPs of the U. lactuca-treated groups. In conclusion, biosynthesized ZnO-NPs from seaweed showed potent antimicrobial, antioxidant, and antitumor activities, which can be used in the pharmaceutical industry. Full article

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. Full article

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. Full article

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. Full article