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Sargassum 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]

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]

AbstractAlginate lyase, which catalyzes the cleavage of alginate, has potential biocatalytic applications in agriculture, food, fodder, nutraceutical, pharmaceuticals, medical diagnostic and bioenergy industries. In this study, a novel alginate lyase-producing Streptomyces sp. LB55 (GenBank Accession No. MT176164) was isolated from Sargassum seaweed waste, and its extracted alginate lyase was immobilized onto glutaraldehyde cross-linked silicon dioxide nanoparticles. Fourier-transform infrared (FTIR) spectroscopic analysis suggests the binding of extracted alginate lyase with silicon dioxide nanoparticles via covalent bonds. FTIR analysis also revealed the retention of the secondary structure of immobilized alginate lyase by exhibiting amide I and amide II bands. The glutaraldehyde cross-linked silicon dioxide nanoparticles retained 71.9 ± 2.63% of alginate lyase activity. The optimal pH and temperature for maximal alginate lyase activity were recorded at pH 7.5 and temperatures of 40 and 45 °C, for free and immobilized forms, respectively. In comparison to free alginate lyase, the immobilized enzyme was thermodynamically efficient by displaying higher values of activation energy (52.3 kJ/mol), enthalpy (49.8 kJ/mol) and entropy (–69.7 J/mol/K) of catalysis. The immobilized alginate lyase had a strong affinity for alginate by exhibiting low Km (1.75 ± 0.12 mg/mL) and high Vmax (30.4 ± 2.66 U/mg-protein) values. The immobilized alginate lyase activity was unaffected at 2% NaCl concentration and could be successively reused six times without considerable loss of activity. The overall results demonstrate for the first time the potential of silicon dioxide nanoparticles as an effective matrix to immobilize alginate lyase for sustainable and cost-effective depolymerization of alginate. [ABSTRACT FROM AUTHOR]

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]

Governance generally, and appropriate operational institutions specifically, are said to be crucial to increasing human adaptive capacity amidst environmental change. But existing conceptualizations tend to assume a universal model of governance will work for states of all sizes. This article questions this orthodoxy which disregards the lack of clarity on size-relevant institutional design and functioning. We do so by focusing on the role of governance in the adaptive capacity of small island developing states (SIDS) facing a new marine social-ecological threat. We draw on a unique dataset of capacity self-assessments undertaken by thirty-eight key agencies involved in the management of sargassum seaweed influx events in the Eastern Caribbean. We found support for the findings of public administration scholars who show that country size is a contextual factor affecting adaptive capacity beyond the control of managers. The implication is that the ability of SIDS to adapt to new or emergent environmental change is crucially inhibited by size-related governance constraints while solutions that mitigate these effects – informal networks and regional organizations – are not well captured by existing metrics. To ensure assessments of adaptive capacity are contextually appropriate we need a more nuanced appreciation of the impacts of state size on governance outcomes. [ABSTRACT FROM AUTHOR]

This study investigated the diversity of endophytic fungi isolated from the brown seaweed, Sargassum thunbergia, collected from six coastal regions in Korea: Gangneung, Pohang, Buan, Taean, Tongyeong and Yeosu. A total of 154 fungal strains were isolated using ITS rDNA sequence analysis, resulting in 84 species across 43 genera. Species diversity, assessed based on the Shannon index, was highest in Tongyeong (H′=3.273), followed by Pohang (H′=3.209), Buan (H′=2.691), Yeosu (H′=2.649), Gangneung (H′=2.342), and Taean (H′=2.025). Principal Coordinates Analysis (PCoA) revealed that water temperature and dissolved oxygen are the primary environmental factors influencing the regional variation in fungal community structure. This study underscores the significance of environmental conditions in shaping the diversity and community composition of endophytic fungi in S. thunbergii. [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]

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]

Effective monitoring of non-indigenous seaweeds and combatting their effects relies on a solid confirmation of the non-indigenous status of the respective species. We critically analysed the status of presumed non-indigenous seaweed species reported from the Mediterranean Sea, the Northeast Atlantic Ocean and Macaronesia, resulting in a list of 140 species whose non-indigenous nature is undisputed. For an additional 87 species it is unclear if they are native or non-indigenous (cryptogenic species) or their identity requires confirmation (data deficient species). We discuss the factors underlying both taxonomic and biogeographic uncertainties and outline recommendations to reduce uncertainty about the non-indigenous status of seaweeds. Our dataset consisted of over 19,000 distribution records, half of which can be attributed to only five species (Sargassum muticum, Bonnemaisonia hamifera, Asparagopsis armata, Caulerpa cylindracea and Colpomenia peregrina), while 56 species (40%) are recorded no more than once or twice. In addition, our analyses revealed considerable variation in the diversity of non-indigenous species between the geographic regions. The Eastern Mediterranean Sea is home to the largest fraction of non-indigenous seaweed species, the majority of which have a Red Sea or Indo-Pacific origin and have entered the Mediterranean Sea mostly via the Suez Canal. Non-indigenous seaweeds with native ranges situated in the Northwest Pacific make up a large fraction of the total in the Western Mediterranean Sea, Lusitania and Northern Europe, followed by non-indigenous species with a presumed Australasian origin. Uncertainty remains, however, regarding the native range of a substantial fraction of non-indigenous seaweeds in the study area. In so far as analyses of first detections can serve as a proxy for the introduction rate of non-indigenous seaweeds, these do not reveal a decrease in the introduction rate, indicating that the current measures and policies are insufficient to battle the introduction and spread of non-indigenous species in the study area. Non-indigenous seaweed species in the Northeast Atlantic Ocean, the Mediterranean Sea and Macaronesia are critically reanalysed. > 19,000 distribution records revealed considerable variation in diversity of non-indigenous seaweed species in the study area. Taxonomic and biogeographic uncertainties hamper a critical evaluation of the non-indigenous status of many seaweed species. [ABSTRACT FROM AUTHOR]

Burn injuries, affecting local skin disruption as well as inducing systemic inflammatory responses, are presented as a global public health problem. To enhance the effects of burn wound healing, treatment must simultaneously regulate both re-epithelialization and hyperinflammation. Extracts of Sargassum horneri (S. horneri) have shown a potential to enhance skin wound healing through antioxidative properties, immune enhancement, and modulation of inflammatory responses. However, despite its promising application for burn wound healing, specific investigation into S. horneri-derived compounds for enhancing wound healing has not yet been conducted. In this research, we investigated the burn wound-healing effect of the low-temperature pulverization-specific S. horneri extract (LPSHE), which could not be detected using the room-temperature grinding method. In a mouse burn model with third-degree burn injuries, LPSHE accelerated re-epithelialization by promoting the increase in F-actin formation and reduced burn-induced ROS levels. Additionally, LPSHE significantly regulated hyperinflammation by reducing pro-inflammatory cytokines. Further investigation into molecular mechanisms using HaCaT keratinocytes also demonstrated beneficial effects on burn wound healing. Taken together, our findings suggested that LPSHE is a promising therapeutic candidate for enhancing burn wound healing. Furthermore, this research underscored the importance of low-temperature pulverization in discovering novel natural compounds from marine organisms. [ABSTRACT FROM AUTHOR]

To improve the quality of Sargassum fusiforme seedlings, suitable strains of juveniles regenerated from holdfasts need to be bred. In this study, effects of different temperatures (16, 20, and 24 °C) and irradiances (100, 120, and 160 µmol photons·m−2·s−1) on the growth of juveniles (new individuals) from the holdfasts of S. fusiforme were investigated to provide strategies for the cultivation of vegetative propagation seedlings of S. fusiforme. The results demonstrated that during cultivation at 24 °C, the regenerated juveniles rotted after twenty-one days, and their relative growth rate, photosynthetic activity and pigment content decreased substantially. The low temperature of 16 °C also decreased their photosynthetic activity and growth considerably. At a high irradiance of 160 µmol photons·m−2·s−1, the growth rate and photosynthetic activity decreased. Under conditions of 20 °C and 120 µmol photons·m−2·s−1, juveniles showed higher photosynthetic activity and nitrate uptake rates, which increased the growth of the juveniles and lateral branches and promoted the accumulation of photosynthetic pigment. Therefore, culture conditions of 20 °C and 120 µmol photons·m−2·s−1 can be applied for early indoor cultivation of regenerated juveniles of S. fusiforme. This study provided technical support for solving the problem of single provenance of S. fusiforme seedlings. [ABSTRACT FROM AUTHOR]

Raw earth construction (RE) is an interesting alternative approach for reducing the use of conventional construction materials. The aim of this study is the stabilization of RE by a new organic binder manufactured based on algae. The stabilization is performed on the mortar scale as well as evaluated by conducting mechanical and thermal tests. Samples of mortar were manufactured based on local soil and Sargassum muticum type algae. The incorporation weight rates of algae are 0 (reference sample), 2, 4, 6, and 8 wt.%. Results showed that the compressive and bending strengths of algae mortar were improved by 77 and 70%, respectively. In addition, it was noticed that samples with 0.63 mm maximum grain size algae binder provide higher strengths in comparison with 0.80 mm maximum grain size algae binder. It was found also that 2 wt.% of incorporated algae provide similar mechanical resistance to 15 wt.% of slaked lime. The thermal investigation of samples showed three peaks: two endothermic peaks at 100 and 800 °C, which can be respectively attributed to the desorption of H2O and CO2 due to the decomposition of calcite; the third exothermic peak at 500 °C is attributed to the decomposition of the macromolecules of the algae. [ABSTRACT FROM AUTHOR]

The concept of floating algae index (FAI), a measure of the red-edge reflectance of floating vegetation, has been used to map floating macroalgae in global oceans. However, when the algae mats are submerged in water due to winds and other factors, the reduced reflectance (and thus reduced FAI value) is interpreted as being caused by reduced areal density (or biomass density) of algae, leading to underestimated algae amount. Here, a depth invariant FAI is proposed to overcome this difficulty. The depth invariant FAI is formulated using three spectral bands whose selective water attenuations can compensate for the reduced reflectance, resulting in FAI values that are nearly independent of the submerged depth of up to 30 cm with underestimates of the algae amount reduced from >50% to a few percent. In this study, the concept of depth invariant FAI is demonstrated through simulations only. With the new Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission and other hyperspectral satellite missions in the near future, such a concept is expected to be tested and evaluated with satellite data, from which the optimal bands can be selected to reduce uncertainties in mapping floating macroalgae. [ABSTRACT FROM AUTHOR]

Coastal communities of the Caribbean Sea and Gulf of Mexico have been affected by atypical influxes of pelagic macroalgae (Sargassum genus) since 2011, entailing ecological, economic and social impacts in need of characterization. We compiled and documented local ecological knowledge (LEK) and perceptions across diverse stakeholder groups from coastal communities in Mexico (Quintana Roo) (n=50 participants) and the United States (Florida) (n=36 participants) through on-site and online interviews and workshops undertaken from January to March of 2022, to understand how the knowledge of this phenomenon varies among communities and to characterize ecological and well-being impacts. Participants in Quintana Roo associated these influxes with both global phenomena (e.g., climate change) and local scale processes (e.g., currents/wind patterns) while Florida participants associated these events more with the latter. The communities in both regions perceived that the economy and the environment were the most impacted well-being categories. While influxes effects were mostly negative (80%) according to Quintana Roo participants (e.g., affected fisheries), Florida participants considered many positive effects of Sargassum (40%) on several well-being and ecological components (e.g., nursery habitat for marine species). In general, the perception of Sargassum as a problem was less pronounced in Florida, and these differences in perception are related to the magnitude of these influxes' effect on the daily life of these communities. Overall, macroalgae management is still mainly focused on beach cleanup. Documenting LEK is important to delineate scientific research priorities and to provide decision makers with resources to develop efficient public policies and coastal management decisions. [ABSTRACT FROM AUTHOR]

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

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

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

In recent years, two types of macroalgae, namely, Ulva prolifera and Sargassumhorneri, have appeared occasionally together in the Yellow Sea and the East China Sea. Remote sensing enables timely and cost-effective observation of macroalgae across large areas. In the available studies, the recognition and classification of the two macroalgae are primarily based on spectral difference analysis. In this study, the spectral features, indices and textural feature parameters of the macroalgae targets were extracted and a preliminary multi-feature dataset was constructed based on Sentinel-2 images. Feature selection was performed using SHAP-based importance analysis and Bhattacharyya distance. From this, a multi-feature dataset was created and used as an input to a deep semantic segmentation network of improved ResUnet. The experiments of intelligent recognition and classification of U. prolifera and S. horneri were carried out using the proposed multi-feature-based ResUnet algorithm, with specific F1-scores of 96.7% and 96.8%, respectively. The proposed multi-feature-based ResUnet algorithm can obtain efficient and high-accuracy results for the recognition and classification of marine floating macroalgae. It achieves accurate remote sensing monitoring of the two types of marine floating macroalgae and has significant theoretical research significance and practical application value. [ABSTRACT FROM AUTHOR]

The applications of β-mannanase for environmentally friendly manufacture of biofuels, biological detergents and health-promoting manno-oligosaccharides have garnered research interests for sustainable and cost-effective production of this industrially important enzyme by identifying potent microorganisms to be applied as the biocatalyst and by using cheap feedstocks in the fermentation medium. The current study has optimized the solid-state fermentation (SSF) conditions with cow dung as the economical feedstock for maximal production of β-mannanase by a novel Streptomyces sp. LB66 (GenBank accession no. MT228944) isolated from Sargassum seaweed waste. Furthermore, homology modelling and molecular docking approaches were applied to elucidate the 3D-structure and enzyme–substrate interactions of modelled β-mannanase. The optimization of SSF components via a 23-factorial central composite design recorded the maximal β-mannanase production (36.8 ± 1.74 U/mg-protein) with 18 g cow dung, and at pH 7.5 and 30 °C incubation temperature. Molecular docking of modelled β-mannanase with mannobiose, mannotriose and mannotetraose as substrates displayed participations of six shared active site residues (Arg46, Ala54, Val56, Gln279, Leu281 and Gly282) for the binding. These identified active site residues can be targeted via directed evolution approaches in tailoring the enzymatic traits for overproduction of β-mannanase and in ecofriendly bioprocessing of diverse lignocellulosic and seaweed waste. [ABSTRACT FROM AUTHOR]

In this study, the marine alga Sargassum siliquastrum was used for the first time as a stabilizer for the preparation of manganese sulfide nanoparticles (MnS NPs). After characterization, the resulting MnS NPs were literature-first applied for adsorption of malachite green (MG) cationic dye. Characterizations indicated the formation of a spherical, monodispersed, mesoporous mixture of γ-MnS (56%) and α-MnS (46%) with a small crystallite size of 19 nm and a high surface area of 156.7 m2/g. After stepwise optimization of various parameters affecting the adsorption process, MG was 99.7% removed within 60 min from neutral solution by 0.2 g/L of MnS NPs at 298 K. The data of MG adsorption are best fitted by Langmuir isotherm (R2 ≥ 0.99) with a maximum adsorption capacity of 432.2 mg/g at 328 K. Pseudo-second order (R2 = 0.99) is the most appropriate to describe adsorption kinetics. In addition, thermodynamic results revealed that the adsorption is endothermic and spontaneous. Stability and interference studies showed that MnS NPs are highly stable and more selective for MG removal than other dyes. Upon these results, MnS NPs can be applied for the effective removal of MG from various water samples. [ABSTRACT FROM AUTHOR]

In order to add value to the beach-cast Sargassum cymosum algae, its biomass was converted by pyrolysis process at 800°C into biochar, characterized and applied in the adsorption of Acetaminophen in batch and fixed-bed processes. Characterization by pH, Point of Zero Charge (pHPZC), Fourier-Transform Infrared Spectroscopy (FTIR), Thermogravimetric (TG), Scanning Electron Microscopy (SEM) and Surface area (BET) showed that the biochar presents properties favourable for the Acetaminophen adsorption. High surface area was obtained of 368.1 m². g−1, presenting the formation of pores, observed by SEM. The biochar showed basic characteristics (pH = 8.84 and pHPZC = 9.9), inferring an adsorption involving several different mechanisms such as dispersive interactions by π electrons, electrostatic attractions, and hydrophobic interactions. The adsorption mechanism is limited by chemisorption and governed by the formation of monolayer on the biochar surface, the Pseudo-second order kinetic and Langmuir-Freundlich isotherm model described the best behaviour of batch adsorption, with equilibrium and maximum adsorption capacity q e = 6.93 ± 0.07 mg. g−1 and q m s = 12.34 ± 0.45 mg. g−1, respectively. Fixed-bed adsorption were performed varying adsorbent mass (0.3 and 0.6 g) and flow rate (2.5 and 5.0 mL. min−1), the best q y = 42.33 mg. g−1 found to adsorbent mass of 0.6 g and flow rate of 2.5 mL. min−1. Yan model described the best behaviour of the breakthrough curves data. Thus, the results provide insights into the development of adsorbents from beach-cast of Sargassum cymosum to adsorption of Acetaminophen, enhancing the use of environmental waste to obtain it. [ABSTRACT FROM AUTHOR]

Heavy metal in wastewater is a problem due to its unsafe nature to the surroundings. The adsorption characteristics of brown algae Sargassum myriocystum for Zn2+ ions uptake from metal solutions was investigated. Among various algal pretreatment HCl was found to be the best and was characterized with various methods for example BET, DSC-TGA, proximate and composition analysis, and Point of zero charges. Experiments were performed and adsorption reaches equilibrium at 60 min at pH 5.5 and adsorbate dose decreased when increasing metal concentration 50 g/l and 200 mg/l, respectively. Maximum adsorption efficiencies of Zn2+ ions take place at temperature 30°C and 0.5 g of algae biomass was found to be optimal, with an agitation speed of 150 rpm. Our results suggest that HCl-treated adsorbent could be used as a more effective adsorbent than untreated S. myriocystum for the uptake of Zn2+ from metal solution. Kinetics study was performed for evaluating the sorption kinetics and the obtained data fit best to the pseudo-second-order model for zinc ion when compared with all other given models. It was observed that the Freundlich isotherm showed a good fit to the equilibrium sorption data and shows the highest correlation coefficient values (R2 > 0.90) for zinc, whereas in Van't Hoff plots a positive value of ΔH°, a negative value of the free energy (ΔG°) and a positive value of ΔSo showed increased randomness at the solid/solution interface as well as the process being feasible and spontaneous by plotting 1/T vs ln Kc. [ABSTRACT FROM AUTHOR]

Pelagic Sargassum is a buoyant macroalgae that forms rafts at the ocean surface and serves as a biologically rich habitat for hundreds of diverse marine species. Since 2011, massive blooms of Sargassum have occurred in the tropical Atlantic and swept through the western tropical Atlantic, Caribbean Sea, and Gulf of Mexico. These recurring annual events have caused significant disruptions to coastal communities throughout the region, negatively impacting human health, tourism, fishing, navigation, and nearshore ecosystems. We present here the Sargassum Inundation Report (SIR), a product that uses satellite-based methodology to estimate and predict the future coastal inundation of pelagic Sargassum. Results from one year of SIRs show strong spatiotemporal differences in the potential of coastal inundation across the Intra-American Seas, and provide a comprehensive method for assessing its geographic distribution and temporal variation. Comparisons of SIRs to opportunistically collected photographs indicate a qualitative concordance between satellite and in situ observations. This work highlights the value of satellite observations, basin-wide and seasonal monitoring, and emphasises the need for sub-regional and weekly forecasting. SIRs show considerable promise as a tool that can eventually incorporate improved spatiotemporal resolution Sargassum imagery, ocean circulation, wind, and wave conditions to forecast the movement of Sargassum into coastal areas. [ABSTRACT FROM AUTHOR]

Sargassum horneri (Turner) C. Agardh (S. horneri) is brown algae that grows on the broad ranges in the Western Pacific, spanning from Northern Japan to the Philippines. S. horneri has been used as local food and traditional medicine for thousands of years in East Asia. However, little is known about its effects on benign prostatic hyperplasia (BPH). In this study, we investigated the effects of S. horneri extract in testosterone propionate (TP)-induced BPH in vitro and in vivo. Treatment with S. horneri extract significantly decreased the expression of androgen receptor, prostate-specific antigen, and 5α-reductase type 2 in TP-induced BPH in vitro and in vivo. Additionally, S. horneri extract treatment significantly increased the Bax/Bcl-2 ratio, indicating increased cell apoptosis. Therefore, these results collectively show that S. horneri extract can alleviate TP-induced BPH and the possibility of using S. horneri extract as a therapeutic agent for the treatment of BPH. [ABSTRACT FROM AUTHOR]

Sargassum is one of the most important economic algae in Phaeophyta. It has broad prospects for development and application in industry, agriculture, food, medicine and ecological restoration, and plays an important role in maintaining the marine ecosystem. In recent years, however, environmental degradation, offshore farming and overharvesting have changed the ecosystem structure and threatened the Sargassum resources. To understand the composition and characteristics of Sargassum in Hainan, we conducted an annual field survey of four bays around Hainan Island, including Haiwei, Qinglan, Lingshui and Sanya. Results indicated that 16 species of Sargassum were collected in the intertidal zone of Hainan Island, belonging to two subgenera, three sections, and S. polycystum was the dominant species at all stations throughout the year. Lingshui and Sanya had the highest biodiversity index, followed by Qinglan and Haiwei. The community similarity between Qinglan and Lingshui was the highest, followed by Haiwei and Sanya. The biodiversity index of Sargassum was the highest in summer, followed by late spring and autumn, and the lowest in winter. [ABSTRACT FROM AUTHOR]

Brown seaweeds are known natural antioxidants and antiviral candidates. This study aimed to extract and characterize polysaccharides from Sargassum euryphyllum and Sargassum aquifolium brown macroalgal species and investigate their antiviral potential against avian infectious bronchitis virus (IBV). The chemical composition of the polysaccharides was characterized by Fourier transform infrared spectrometry, proton nuclear magnetic resonance, gel permeation chromatography, and high-performance liquid chromatography. Antioxidant activity was also determined as 2,2-diphenyl-1-picrylhydrazyl (DDPH) radical, hydrogen peroxide radical scavenging, and total antioxidant activity. Data revealed that S. aquifolium polysaccharides encompass significant ash (17.84% ± 0.69%), carbohydrates (57.43% ± 0.40%), sulfates (18.26% ± 0.52%), and uronic acids (45.40% ± 0.39%) content compared to S. euryphyllum polysaccharides. The molecular weight (MW) recorded 557 kDa for S. aquifolium polysaccharide with neutral sugars of mannose, galactose, and fructose, which constituted bulk molar ratios. A lower MW of 317 kDa was recorded for S. euryphyllum polysaccharide with mannose and xylose as the dominant neutral sugars. Both polysaccharides showed no cytotoxicity on chicken embryo kidney (CEK) cells. Potent antioxidant activity, measured as DPPH assay, for S. euryphyllum (59.15% ± 2.75%) and S. aquifolium (65.25% ± 2.89%) polysaccharides was established compared to ascorbic acid (67.33% ± 2.24%). The IBV titer on CEK cells in vitro showed a decreasing pattern from 5.4 to 4 log10 median tissue culture infectious dose (TCID50)/ml with S. euryphyllum polysaccharide and from 4.5 to 2.2 log10 TCID50/ml with S. aquifolium polysaccharide within 6 days post incubation time. A similar significant anti-IBV activity was estimated in vivo for both polysaccharides with a chorioallantoic membrane inoculation assay. Decreasing IBV titer suggested blocking of the virus entry, probably through disturbing its binding to the host cell receptors. The study recommended sulfated polysaccharides of S. aquifolium and S. euryphyllum seaweeds as potential antioxidants and antiviral natural resources. [ABSTRACT FROM AUTHOR]

The merits of polycentric climate governance have attracted considerable discussion. On the one hand, polycentric governance offers an alternative to top-down state-centric forms that have so far proven elusive. On the other, highly networked systems increase coordination challenges. Less attention has been paid to the varying capacities required to achieve coordination. In this article we explore the coordination of polycentric governance via a case study of sargassum influx management in the Caribbean. Since 2011, large quantities of sargassum seaweed have been washing up on Caribbean beaches with adverse socio-economic impacts. Our analysis of sargassum management policies reveals that a nascent polycentric system has generated significant cooperation in policy development and application across the region. However, there remain national capacity deficits to engage in this form of governance and to implement agreed actions. We conclude that advocates of a polycentric climate governance regime need to consider how capacity shapes participation, to the advantage of the largest and strongest. Polycentric governance can be useful for solving disparate cross-border environmental problems, but it also imposes a cost on the smallest that has thus far been unacknowledged and undertheorized. [ABSTRACT FROM AUTHOR]

Bioactive compounds from marine macroalgae are gaining immense attention for their application as natural ingredients in various nutraceuticals and food supplements. The present study evaluated the medicinal properties of the organic extracts of four each of brown and red marine macroalgal species, using various in vitro assays. Organic extracts of brown algae of Fucophycidan subclass, such as Sargassum plagiophyllum, Turbinaria decurrens, and red alga Hydropuntia edulis, displayed potential inhibitory properties against antioxidants (IC50 0.2–0.8 mg/mL) and carbolytic enzymes (IC50 0.2–0.9 mg/mL) compared to those exhibited by other studied algae. Noticeably, organic extracts of red alga H. edulis and brown alga T. decurrens could effectively attenuate pro-inflammatory 5-lipoxygenase (IC50 0.4–0.6 mg/mL), thereby demonstrating their potential application to dissuade inflammatory pathogenesis. This study demonstrated the predominantly available brown and red macroalgae as potential marine bioresources to develop functional food candidates. [ABSTRACT FROM AUTHOR]

Oxidative stress and reactive oxygen species (ROS) are primarily responsible for the development of male infertility after exposure to γ-irradiation. The present work aimed to assess the ameliorative and therapeutic roles of the aqueous and ethanolic extracts of the edible seaweed Sargassum virgatum (S. virgatum) on spermatogenesis and infertility in γ-irradiated Wistar rats. Induction of infertility was performed by exposing the rats to 137Cs-gamma rays, using a single dose of 3.5 Gy. γ-irradiated rats were given the S. virgatum ethanolic (S. virgatum-EtOH) and aqueous extracts intraperitoneally on a daily base for two consecutive weeks at doses of 100 and 400 mg/kg body weight (b.wt.) for each seaweed extract. Morphometric data of the testes, semen quality indices, antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx), and deoxyribonucleic acid (DNA) fragmentation were assessed. The results obtained were taken during two-time intervals of 15 and 60 days from the commencement of the algal treatments. In vitro antioxidant assays and polyphenolic compounds of S. virgatum were characterized. Significant negative changes in the semen quality and morphometric data of the testes, as well as remarkable DNA fragmentation, were detected in the irradiated rats compared to the control. The levels of the endogenous antioxidant enzymes (SOD, CAT, GSH, and GPx) were also significantly diminished. Nonetheless, treatments of γ-irradiated rats with the S. virgatum-EtOH and aqueous extracts significantly improved the above-mentioned enzymes, in addition to noteworthy amendments in the dimensions of the testes, the semen quality, as well as the DNA structure. The ameliorative potency of S. virgatum to cure γ-irradiation-induced male infertility, particularly 400 mg/kg ethanolic extract for 60 days, is the result of the consistent therapeutic interventions of its potent antioxidant and anti-apoptotic polyphenols, particularly protocatechuic, p-hydroxybenzoic, rosmarinic, chlorogenic, cinnamic and gentisic acids, as well as the flavonoids catechin, hesperidin, rutin and quercetin. Besides its high-value nutraceutical importance, S. virgatum could be a natural candidate for developing well-accepted radioprotectant products capable of treating γ-irradiation-induced male infertility. [ABSTRACT FROM AUTHOR]

Alginate lyase has the potential for the ecofriendly depolymerization of alginate and generation of value-added products important in agriculture, bioenergy, food processing, medical diagnostic and pharmaceutical industries. Substantial research has focused on the cost-effective production of alginate lyase via screening of potent microbial isolates for use as biocatalysts and the optimization of fermentation media with low-cost feedstocks. This study evaluated the alginate lyase-producing efficacy of a novel Pseudomonas sp. LB56 (GenBank accession no. MT176182) isolated from Sargassum seaweed waste. The feedstock for solid-state fermentation (SSF) was decomposed Sargassum biomass amended with cow dung. The production of alginate lyase was maximal using 9.5 g Sargassum, 14 g cow dung and at pH 8 after optimization via a 23–factorial central composite design. Comparative modelling and molecular docking studies were conducted to elucidate the 3D structure of the alginate lyase of this novel isolate, as well as to investigate its catalytic interactions with different polymeric sizes of alginate [polymannuronate (mannuronate disaccharide and mannuronate trisaccharide), polyguluronate (guluronate disaccharide and guluronate trisaccharide) and alginate]. The overall results suggest that biowaste (Sargassum seaweed amended with cow dung) can be used as a feedstock for economical production of alginate lyase. Additionally, the identified active site residues of alginate lyase, which were shared by different polymers of alginate, can be tailored via rational and/or combinatorial approaches for efficient biotransformation of alginate-enriched wastes into biologically active alginate oligomers and third generation biofuels. [ABSTRACT FROM AUTHOR]

A change detection analysis utilizing Very High-resolution (V.H.R.) satellite imagery was performed to evaluate the changes in coastal vegetation in La Parguera, southwestern Puerto Rico, attributable to the increased influx of pelagic Sargassum and its accumulations in cays, bays, inlets and near-shore environments. Imagery was co-registered, corrected for atmospheric effects and masked for water and land. A Normalized Difference Vegetation Index (N.D.V.I.) was used to evaluate the changes in coastal vegetation. N.D.V.I. was used to calculate the differences from 2010 baseline imagery to potential hurricane plus Sargassum impacts (2018 image) and potential Sargassum impacts (2020 image). Results show a total decrease in N.D.V.I. from 2010 to 2020 of 28%, or 3,687,493 m2, and these changes were also observed in true colour images. Total decrease in values in N.D.V.I. was higher from 2018 to 2020, especially for the Isla Cueva site (233,807 m2), and were consistent with the field observations and drone surveys conducted since 2018 in the area. Areas prone to Sargassum accumulation were also identified. This approach provides a quantifiable method to evaluate Sargassum impacts to the coastal vegetation and benthic composition using change detection of V.H.R. images and to separate these effects from other extreme events. [ABSTRACT FROM AUTHOR]

Chemical analysis of the organic extract from intertidal brown seaweed Sargassum ilicifolium (family Sargassaceae) characterised an undescribed xenicane-type diterpenoid sargilicixenicane, elucidated as 3-(17-hydroxy-14-methylhept-13-en-10-yl)-6-methylhexahydro-1H-cyclonona[c]furan-4,19-diyl diacetate (compound 1). The studied compound exhibited prospective free radical quenching potential (IC50 1.2-1.4 mM) in comparison with commercial antioxidant (α-tocopherol, IC50 > 1.40 mM). Attenuation property of sargilicixenicane against pro-inflammatory enzyme, 5-lipoxygenase (IC50 4.70 mM) was comparable with that displayed by the non-steroidal anti-inflammatory agent ibuprofen (IC50 4.51 mM). Greater selectivity index displayed by the studied xenicane-type diterpenoid (1.42) than that exhibited by ibuprofen (0.44) recognised the selective attenuation potential of the former against the inducible cyclooxygenase-2 and 5-lipoxygenase enzymes. Higher electronic parameters (topological polar surface area, 82.06) and balanced hydrophobic-hydrophilic property (octanol-water partition coefficient 2.94) coupled with docking score (-11.17 kcal mol−1) and lower binding energy (-9.61 kcal mol−1) with the active site of 5-lipoxygenase supported the significant anti-inflammatory properties of the studied xenicane-type diterpenoid. [ABSTRACT FROM AUTHOR]

This study evaluates and compares several machine learning methods on the effects of different parameters in the hydrothermal carbonisation (HTC) process of macroalgae Sargassum horneri. Reaction temperature, residence time, biomass particle size, the amount of catalyst and loaded biomass were considered as inputs and three variables of BET, higher heating value (HHV) and energy recovery were regarded as outputs. For analysing the input parameters, the Taguchi method was used for experimental designs and the obtained results were utilised here as training sets. Various data mining approaches like support vector machine (SVM), group method of data handling, decision tree, random forest, radial basis function, adaptive neuro-fuzzy inference system (ANFIS) and multilayer perceptron (MLP) neural network were implemented to model the problem and two different optimisation techniques named BAT and Grasshopper Optimisation Algorithm (GOA) were employed with MLP and ANFIS model for optimising. By comparing different statistical parameters such as Average Absolute Relative Deviation (AARD), coefficient of determination (R2), Root Mean Square Error (RMSE) and Standard Deviation (SD), It is found out that SVM method has a considerably better performance relative to other methods for estimating both the BET, HHV and energy recovery parameters. Furthermore, coupling of MLP and ANFIS with GOA increases the accuracy of these models for BET, HHV and energy recovery estimations. [ABSTRACT FROM AUTHOR]

Sargassum horneri (Turner) C. Agardh (Sargassaceae) is a brown marine alga used in oriental medicine to treat allergic conditions. This study clarifies the effect of polyphenol-containing S. horneri ethanol extract (SHE) on T-helper type-2 (Th2) polarisation. All mice (BALB/c mice, n = 12) except in the healthy control group were first sensitised with an intraperitoneal injection of ovalbumin (OVA; 20 µg) and alum (2 mg) on Day 0 and Day 14. Similarly, phosphate-buffered saline (PBS) was injected according to the same schedule into the healthy control mice. After the final administration, splenocytes were obtained. OVA sensitised mice were challenged with OVA (100 µg/mL) in the absence or presence (62.5 and 125 µg/mL) of SHE while healthy control group remained untreated. SHE (0–1000 µg/mL) was not cytotoxic to splenocytes and demonstrated IC50 values of 3.27 and 3.92 mg/mL, respectively, at 24 and 48 h of incubation. SHE suppressed cell proliferation at concentrations ≥62.5 µg/mL. SHE treatment (125 µg/mL) subdued (by 1.8-fold) the population expansion of CD3+CD4+ helper T cells induced by OVA challenge. SHE attenuated the OVA-induced activation of respective transcription factors GATA3 and NLRP3. Simultaneously, highly elevated levels of cytokines interleukin (IL)-4 and IL-5 caused by OVA stimulation were removed completely and IL-13 suppressed by 1.5-fold. SHE exhibits Th2 immune suppression under OVA stimulation via GATA3- and NLRP3-dependent IL-4, IL-5, and IL-13 suppression. Therefore, SHE could be therapeutically useful for alleviating the symptoms of allergen-mediated immune diseases. [ABSTRACT FROM AUTHOR]

Indian edible brown seaweed, Sargassum wightii, hydrothermally processed (by boiling and microwave treatment) until an edible texture was attained and then extracted in different solvents, including acetone, chloroform, ethyl acetate, and methanol to obtain dry extracts. Swelling capacity and oil holding capacity of the processed seaweed was found to be significantly higher (p < 0.05); while water holding capacity was significantly lower (p < 0.05) after thermal processing as compared to the control. There was significant (p < 0.05) increase in the phytochemical content and antioxidant activity after thermal processing compared to the control. Phenolic and flavonoid compounds were found to be well extracted in the less polar solvents, i.e., chloroform and ethyl acetate and these results correlated well with the DPPH free radical scavenging activity. Results suggested that bioactive compounds in S. wightii are stable towards thermal treatment making this seaweed a potent candidate to formulate processed functional food products. [ABSTRACT FROM AUTHOR]

The invasive brown alga Sargassum muticum was first recorded in Norway in 1988 and is presently common in the sublittoral fringe on the sheltered coast in South Norway. Here, results from a study on mesofauna associated with S. muticum in an archipelago on the southwest coast of Norway are presented, with two stations placed in sounds exposed to tidal currents and two in sheltered bays. Sargassum muticum occurred with a patchy distribution and an estimated density of less than 7 individuals m−2 at three of the stations (two in sheltered bays and one in a sound) and 42 individuals m−2 at the fourth station (placed in a sound). A total of 102 distinct faunal taxa were identified, with an average of 31 taxa per sample. Crustacea and Gastropoda constituted around half of the identified taxa. Fauna richness showed no relation to site type but had a curvilinear correlation with habitat size (dry weight of thallus). Total and sessile fauna richness showed a significant negative correlation with branching density. Vagile faunal density showed a curvilinear correlation with weight of epiphytes and was significantly related to site type with higher densities in the bays. The community composition of vagile fauna reflected this and was significantly related to site type, but not to epiphyte weight or branching density. When including sessile taxa in a community analysis the stations became less separated, and the community was significantly influenced by branch density. Thus, both site characteristics and morphology of S. muticum influenced the associated fauna community. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the chemical composition and anti-bacterial properties of the bioactive principles of Sargassum aquifolium (Turner) C.Agardh, a brown seaweed in Red sea of Jazan province, Kingdom of Saudi Arabia. Crystals were obtained from the petroleum ether extract of Sargassum aquifolium and subjected to chemical tests, FTIR spectroscopic analysis and NMR analysis to identify their chemical composition, and to study their antibacterial properties against selected human pathogenic bacteria. In addition, GC–MS analysis was performed to identify the bioactive compounds in the crude petroleum ether extract. Results of the antibacterial effect of the crystal analyte showed a wide spectrum of activity against the screened human pathogenic bacteria. [ABSTRACT FROM AUTHOR]

The ecology and biogeography of the invertebrate epifauna related to floating Sargassum in the East China Sea were studied. Floating algal rafts composed of only Sargassum horneri (Turner) C. Agardh were collected in the East China Sea in March 2012 when the rafts were distributed not only on the continental shelf but also, unusually, south and east of the Kuroshio Current in the Pacific Ocean. In total, 71 samples collected at 11 stations were studied. Of the 11 invertebrate taxa recognized, harpacticoid copepods were most abundant, followed by malacostracans, and cirripedes. The densities of these three taxa were higher than those of other invertebrates. The number of invertebrate taxa was not correlated with the algal wet weight. There were more invertebrate taxa in the coastal area around Amami-Oshima Island than in other areas. The trajectories of drifting buoys indicated that the algal rafts collected in this area floated longer than those in other areas, allowing the colonization of invertebrates from the surrounding water. [ABSTRACT FROM AUTHOR]

Since 2011, there have been ongoing massive unexplained increases of sargassum seaweed strandings along the coastlines of Caribbean countries. The objective of our study was to describe the clinical characteristics of patients exposed to noxious emissions of decomposing sargassum seaweed. This observational study included patients from January 2018 to December 2018 for complaints attributed to decomposing sargassum seaweed. History and geographical characteristics of sargassum seaweed strandings as well as detection of ambient air hydrogen sulfide (H2S) levels were documented during the inclusion period. A total of 154 patients were included. Mean exposure period was 3 months. Neurological (80%), digestive (77%) and respiratory (69%) disorders were the most frequent reasons for medical visit. Temporal distribution of medical visits was related to history of strandings. Geographical origins of patients were consistent with the most impacted areas of strandings as well as the most elevated ambient air H2S levels. The toxicological syndrome induced by sargassum seaweed exposure is close to the toxidrome associated with acute H2S exposure in the range of 0–10 ppm. Our study suggests that patients living in massive stranding areas may be exposed to H2S > 5 ppm for 50 days per year. [ABSTRACT FROM AUTHOR]

The main objective of the study is to evaluate the extraction efficiency methods followed by freeze-drying of bioactive brown seaweed polysaccharides (BSPs). Brown seaweeds such as Sargassum wightii, Spatoglossum asperum, Colpomenia sinuosa, Padina tetrastromatica were considered in this study. Conventional solvent extraction (CSE), and advanced extraction techniques such as microwave-aided (MAE), ultrasound-aided (UAE), and enzyme-aided extractions (EAE) were attempted. MAE (2.5 GHz, 15 min) and UAE (50–60 kHz, 30 min) require minimum time and found to be thermal effective compared to the CSE method. EAE exhibited the maximal extraction efficiency of BSPs and S. wightii shown high polysaccharide content (54.99%). The antioxidant activity of all the extracted polysaccharides was evaluated and found to be maximum with P. tetrastromatica. Prebiotic activity assays were attempted on all EAE polysaccharides. Based on antioxidant and prebiotic activity, enzyme-assisted P. tetrastromatica extract was chosen to study for its characteristics using sophisticated analytical techniques. This study signifies the intertwined characteristics of antioxidant properties and shelf life along with its prebiotic activity of freeze-dried bioactive compounds for its desired purpose as a functional ingredient. [ABSTRACT FROM AUTHOR]

Sargassum ilicifolium (Turner) C. Agardh (SI) and Padina tetrastromatica (Hauck) (PT) are tropical and sub-tropical brown algae, found in the coastal region of India. In the present study, the cognitive enhancing activity of chloroform and ethanol extract of SI and PT (CSI, ESI & CPT, EPT) was investigated in scopolamine- induced amnesic mice using the Passive avoidance (PA) test. In addition, the effect on brain oxidative enzymes and acetylcholinesterase (AChE) was also evaluated using a spectrophotometer. The results of this study indicated that CSI (600 mg/kg), ESI (600 mg/kg), as well as CPT (600 mg/kg), significantly increased Step-Down Latency compared to scopolamine treated group, indicated that, CSI, ESI and CPT significantly (p < 0.01) reversed memory deficit produced by scopolamine. Further, administration of CSI (600 mg/kg), ESI (600 mg/kg), as well as CPT (600 mg/kg), produced a significant (p < 0.01) fall in Malondialdehyde and increased in Reduced glutathione activity, indicated that CSI, ESI, and CPT exert a protective effect against oxidative damage induced by scopolamine. Also, it was found that, CSI (600 mg/kg), ESI (600 mg/kg) and CPT (600 mg/kg) significantly (p < 0.05) inhibit AChE activity. These findings resemble the effect of the standard anti-amnesic drug Piracetam. In conclusion, chloroform and ethanol extract of SI and PT shows significant cognitive-enhancing activities by the inhibition enzyme AChE and by the regulation of the oxidative enzymes in scopolamine-induced amnesic mice. However, further research is essential to explore the exact mechanism underlying this activity. [ABSTRACT FROM AUTHOR]

The potential applications of β-mannanase in bioenergy, biorefinery, detergent, fodder, food processing, oil and gas, pharmaceutical, pulp and paper and textile industries, and the high cost of commercially available enzyme have attracted considerable research efforts to identify potent microbial strains for cost-effective production of this enzyme. The advantage of microbial biocatalyst is that the crude enzyme can be used directly in bioprocessing instead of the purified enzyme. In this study, β-mannanase was extracted from a novel Streptomyces sp. Alg-S25 (GenBank accession no. MK494177) and immobilized onto chitosan nanoparticles using glutaraldehyde as a crosslinker. The covalent binding of β-mannanase onto chitosan nanoparticles was confirmed by Fourier-transform infrared spectroscopy. The functionalized chitosan nanoparticles retained 83.6% ± 3.46% of β-mannanase activity. Free and immobilized β-mannanase of this novel Streptomyces sp. Alg-S25 displayed maximal activities at pH 7.5 and at temperature 50 °C and 55 °C, respectively. Immobilized β-mannanase exhibited higher values of activation energy (47.4 kJ/mol), enthalpy (44.9 kJ/mol) and entropy (–73.5 J/mol/K) of catalysis compared to the free enzyme. The substrate-specific kinetic analysis suggested that the immobilized β-mannanase had a strong affinity toward locust bean galactomannan by showing a low Km (4.94 mg/mL) and a high Vmax (93.5 U/mg-protein) values. Furthermore, the immobilized β-mannanase was not affected by 2% NaCl and retained 81.2% of the maximal activity after 10 cycles of successive reuse. These results indicate the potential of chitosan nanoparticle-immobilized β-mannanase for sustainable and cost-effective bioprocessing of mannan-containing agricultural, forest, seaweed and industrial wastes. [ABSTRACT FROM AUTHOR]

In the present study, we have demonstrated the application of two-step optimization strategy for hexavalent chromium (Cr (VI)) adsorption using Sargassum sp in a packed bed column. ANOVA showed that initial metal concentration has larger impact on sorption efficiency. Application of ANN-GA optimization showed promising results among the models tested. The biosorption efficiency accelerated to 90.79% with Cr (VI) conc = 25 mg L−1, Bed height = 11.97 cm and Flow rate = 5.29 mL min−1. The adsorption mechanism was described using kinetic models where Bed depth service time and Yoon–Nelson model showed a better fit for the experimental data with the correlation coefficient of 0.9. [ABSTRACT FROM AUTHOR]

Indole-6-carboxaldehyde (I6CA), an indole derivative isolated from the marine brown algae Sargassum thunbergii, is known to have several beneficial effects, but no studies on immune regulation have been conducted. In this study, the immunomodulatory properties of I6CA on murine RAW 264.7 monocyte/macrophage cells were evaluated. As the concentration of I6CA increased, the morphology of RAW 264.7 cells changed to a typical active macrophage shape, and the phagocytic activity increased significantly. I6CA effectively enhanced the production and secretion of immunomodulatory mediators and cytokines due to increased expression of their respective genes. Additionally, I6CA markedly stimulated the expression of Toll-like receptor 4 (TLR4) and its adapter molecule, myeloid differentiation factor 88 (Myd88), and increased TLR4 complexed with Myd88. Furthermore, I6CA promoted the nuclear translocation of nuclear factor-kappa B (NF-κB) by increasing the degradation of the inhibitor of NF-κB-α. Meanwhile, similar trends were also found in lipopolysaccharide-treated cells as a positive control. Furthermore, molecular docking simulation showed that I6CA interacted with TLR4-myeloid differentiation 2 complex. Taken together, the results support the concept that I6CA may increase the activity of the TLR4/NF-κB signaling pathway in order to enhance the immunomodulatory activity of RAW 264.7 cells. [ABSTRACT FROM AUTHOR]

The brown seaweed Sargassum muticum is one of the best-studied invasive marine species, although most studies are short-term and focus on the expansion phase of invasion. Here I report 30 years of observations of the invasion of the north coast of Spain by S. muticum at regional (400 km coastline) and local scales (at the site where the invasion was first detected). At the local scale, this long-term series reveals a 'boom-bust' process where the expansion ('boom') phase lasted 12 years and the decline ('bust') was completed in 8 years. This cycle is supported by evidence at the regional scale. The impact of S. muticum on the recipient assemblages was only moderate during the initial 'boom' phase of the invasion and negligible afterwards. In conclusion, 30 years after its first observation in the region, Sargassum muticum can be considered an addition to the algal flora rather than a threat to the native assemblages. [ABSTRACT FROM AUTHOR]

We present monthly maps and derived statistics to describe the large-area distribution of Sargassum in the equatorial Atlantic, Caribbean, and Gulf of Mexico, using image data from the OLCI (Ocean and Land Colour Instrument) on the Sentinel 3a satellite. OLCI has provided image data since October 2016 which can be compared with images produced by MERIS (Medium Resolution Imaging Spectrometer) in the period 2002 to 2012. Results show a significant and continuing increase of the area covered by pelagic Sargassum, starting from a first expansion into the Caribbean and equatorial Atlantic in 2011. We use results from a global detection scheme based on the MCI (Maximum Chlorophyll Index) derived from MERIS and OLCI and implemented by ESA's Grid Processing on Demand (GPOD) project. The scheme uses the OLCI image data set at the reduced resolution of 1200m to give monthly global composite images at 5km spatial resolution, designed to record location, extent and intensity of intense plankton blooms and floating vegetation. In the present study area, images are dominated by a growing and spreading distribution of pelagic Sargassum, whose origin and annual cycle remain unexplained. The composite images give no indication of similar populations in other parts of the global ocean. Results derived from MERIS and OLCI are consistent with those derived from MODIS and VIIRS. [ABSTRACT FROM AUTHOR]

Water pollution due to agricultural and industrial processes may cause adverse biological effects in aquatic organisms such as fishes. The removal of brilliant green (BG) dye from aqueous solution using seaweed Sargassum wightii was carried out. Further, it aimed to evaluate the exposure of BG dye activity on hematological, plasma biochemical, enzymological activities and histopathology of Indian major carp, Labeo rohita as a biomarker. High mortality rate (T2 65%) in the fishes exposed to untreated BG dye shows the toxic nature of the dye. Whereas fishes grown in treated BG dye showed less mortality rate (T3 25%) and (T1 30%) which depicts the less toxicity. The observed behavioral, biochemical, hematological and enzymological parameters were showed a significant increase in the treated BG dye. Extensive histopathological lesions in gill, liver and kidney tissues were observed in untreated BG dye compared to fishes grown in S. wightii-treated BG dye might be due to the stress caused by the toxic presence in the dye. The results concluded that S. wightii-treated BG dye does not have any inhibitory effect which reveals the nontoxic nature. [ABSTRACT FROM AUTHOR]

Several species of Sargassum have been reported from the Yucatan peninsula coast, many of which end up as beach cast material, accumulating on the coast during colder months. The phenotypic plasticity of Sargassum makes specimen identification difficult. Two approaches were used in the current study to corroborate identification of the most abundant species: traditional taxonomic characters, and chemical characterisation. Fresh material from eight species of Sargassum was collected on the Yucatan coast. Specimens were identified using the following morphological features: cryptostomata, blade shape and size, and the shape of floating vesicles. Two cell wall polysaccharides, alginate and fucoidan, were extracted, quantified, and characterised from five of the eight species collected. Organic extracts were prepared and GC–MS analyses were performed on the three most abundant species, looking for species-specific compounds. Our analysis identified different chemical constituents depending on the solvent used. In the dichloromethane fraction, hexanoic acid, 2-ethyl was obtained from S. buxifolium whereas benzyl benzoate and epistephamiersine were found in S. hystrix. For the latter species, cholesta-4,6-dien-3-ol, (á)- was found in the hexane fraction, whereas 2,2ʹ-ethyldenebis(4,6- di-tert-butylphenol) and 2-pentadecanone, 6,10,14-trimethyl- were present in S. fluitans. We discuss the applicability and usefulness of this method to assist taxonomic identification of Sargassum species. [ABSTRACT FROM AUTHOR]

We investigated the quality characteristics of cookies prepared using different seaweeds native to the Korean coast. Flour made from four different seaweed species (Sargassum fulvellum, Enteromorpha linza, Codium fragile, and Hizikia fusiforme) was used to replace 5% of the regular flour while preparing the cookies. The seaweeds significantly affected solvent retention capacity, thus interfering with gluten network formation. Consequently, the addition of seaweed changed several variables in the cookies, such as moisture content, spread factor, and breaking stress. In sensory evaluation, cookies with Hizikia fusiforme were the most preferred, confirming the possibility of developing cookie products using this seaweed species. [ABSTRACT FROM AUTHOR]

This study was developed based on the possibility of reusing and valuing the alginate extraction residue (RES) from the algae Sargassum filipendula. The adsorptive properties of RES were explored through kinetic and equilibrium assays in batch mode, in which the kinetic equilibrium time (200 min) was not influenced by the increase of the initial concentration of Ni solutions and the sorption process was favored by the temperature increase. The modeling revealed the simultaneous occurrence of physical and chemical interactions with the external diffusion as the predominant step. The Langmuir model was more representative for the equilibrium results, with an uptake capacity comparable to that of other biomaterials. The thermodynamic study indicated a spontaneous, favorable, and endothermic process, besides the presence of the ion exchange. The isoelectric point was found at pH 5.3, and the pore size distribution allowed the classification of RES as macroporous. The simplified bath sorption design revealed that the required mass of RES become greater for higher quality degrees. However, it is tenable to consider this process viable due to the easy access to the algae biomass and the large amount of the solid waste generated from the alginate extraction (∼50%), termed as residue (RES). [ABSTRACT FROM AUTHOR]