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The effect of different post-harvest treatments (fresh, freezing and air-drying) and storage duration on free amino acid (FAA) content of brown seaweed Fucus vesiculosus were studied. The FAA profile of thalli algae was studied every 3 months over 1 year. The FAA were extracted in ethanol/water (70: 30) solution, purified by ion exchange chromatography, derivatized and determined using hight-performance liquid chromatography. Free amino acid profile was significantly (p<0.001) different among the fresh, freezing and air-drying seaweeds. Long-term storage of seaweeds for 12 months in both dried and frozen form contributed to increased levels of free amino acids. The total free amino acid content increased from 285.80 mg/100 g dry matter of fresh seaweeds to 597.38 mg/100 g dry matter of dried seaweeds and to 473.84 mg/100 g dry matter of the frozen form. The total content of essential amino acids increased from 49.65 mg/100 g dry matter in fresh seaweeds to 130.45 mg/100 g dry matter of dried seaweeds and to 106.70 mg/100 g dry matter of frozen seaweeds. The content of glutamic acid responsible for the taste increased from 132.36 mg/100 g dry matter of fresh seaweeds to 169.50 mg/100 g dry matter of dried seaweeds, and to 242.00 mg/100 g dry matter of frozen seaweeds. Thus, the long-term storage of dried and frozen seaweeds contributes to the improvement of their qualities. [ABSTRACT FROM AUTHOR]

Background: Rockweeds are among the most important foundation species of temperate rocky littoral shores. In the Baltic Sea, the rockweed Fucus vesiculosus is distributed along a decreasing salinity gradient from the North Atlantic entrance to the low-salinity regions in the north-eastern margins, thus, demonstrating a remarkable tolerance to hyposalinity. The underlying mechanisms for this tolerance are still poorly understood. Here, we exposed F. vesiculosus from two range-margin populations to the hyposaline (2.5 PSU - practical salinity unit) conditions that are projected to occur in the region by the end of this century as a result of climate change. We used transcriptome analysis (RNA-seq) to determine the gene expression patterns associated with hyposalinity acclimation, and examined the variation in these patterns between the sampled populations. Results: Hyposalinity induced different responses in the two populations: in one, only 26 genes were differentially expressed between salinity treatments, while the other population demonstrated up- or downregulation in 3072 genes. In the latter population, the projected future hyposalinity induced an acute response in terms of antioxidant production. Genes associated with membrane composition and structure were also heavily involved, with the upregulation of fatty acid and actin production, and the downregulation of ion channels and alginate pathways. Changes in gene expression patterns clearly indicated an inhibition of the photosynthetic machinery, with a consequent downregulation of carbohydrate production. Simultaneously, energy consumption increased, as revealed by the upregulation of genes associated with respiration and ATP synthesis. Overall, the genes that demonstrated the largest increase in expression were ribosomal proteins involved in translation pathways. The fixation rate of SNP:s was higher within genes responding to hyposalinity than elsewhere in the transcriptome. Conclusions: The high fixation rate in the genes coding for salinity acclimation mechanisms implies strong selection for them. The among-population differentiation that we observed in the transcriptomic response to hyposalinity stress suggests that populations of F. vesiculosus may differ in their tolerance to future desalination, possibly as a result of local adaptation to salinity conditions within the Baltic Sea. These results emphasise the importance of considering interspecific genetic variation when evaluating the consequences of environmental change. [ABSTRACT FROM AUTHOR]

A large-scale loss of the habitat-forming macroalgae Fucus vesiculosus was reported around the Baltic Sea in the 1980's, but only relatively local studies have reported its current status. We studied recent comprehensive mapping data in the Finnish marine area and compared reported Fucus occurrences in relation to its potential, to find out its current status on a larger scale. We also investigated the effects of water quality on Fucus occurrence and its depth penetration. Our results show that the status of Fucus is better in the Gulf of Bothnia than in the Gulf of Finland, both in terms of its occurrence rate and its depth distribution. Despite high potential in the outer Archipelago Sea, the status of Fucus is poor. The Fucus occurrence patterns are mainly related to salinity, exposure and Secchi depth, all positively affecting the Fucus occurrence rate and/or the lower limit of the Fucus zone. [ABSTRACT FROM AUTHOR]

Warming is one of the most dramatic aspects of climate change and threatens future ecosystem functioning. It may alter primary productivity and thus jeopardize carbon sequestration, a crucial ecosystem service provided by coastal environments. Fucus vesiculosus is an important canopy-forming macroalga in the Baltic Sea, and its main consumer is Idotea balthica. The objective of this study is to understand how temperature impacts a simplified food web composed of macroalgae and herbivores to quantify the effect on organic carbon storage. The organisms were exposed to a temperature gradient from 5 to 25 °C. We measured and modeled primary production, respiration, growth and epiphytic load on the surface of Fucus and respiration, growth and egestion of Idotea. The results show that temperature affects physiological responses of Fucus and Idotea separately. However, Idotea proved more sensitive to increasing temperatures than the primary producers. The lag between the collapse of the grazer and the decline of Fucus and epiphytes above 20 °C allows an increase of carbon storage of the primary productivity at higher temperatures. Therefore, along the temperature gradient, the simplified food web stores carbon in a non-monotonic way (reaching minimum at 20 °C). Our work stresses the need of considering the combined metabolic performance of all organisms for sound predictions on carbon circulation in food webs. [ABSTRACT FROM AUTHOR]

Context: Fucoidan, a sulphated polysaccharide extracted from brown algae [Fucus vesiculosus Linn. (Fucaceae)], has multiple biological activities. Objective: The effects of fucoidan on Ca2+ responses of rat neurons and its probable mechanisms with focus on glutamate receptors were examined. Materials and methods: The neurons isolated from the cortex and hippocampi of Wistar rats in postnatal day 1 were employed. The intracellular Ca2+ responses triggered by various stimuli were measured in vitro by Fura-2/AM. Fucoidan at 0.5 mg/mL or 1.5 mg/mL was applied for 3 min to determine its effects on Ca2+ responses. RT-PCR was used to determine the mRNA expression of neuron receptors treated with fucoidan at 0.5 mg/mL for 3 h. Results: The Ca2+ responses induced by NMDA were 100% suppressed by fucoidan, and those induced by Bay K8644 90% in the cortical neurons. However, fucoidan has no significant effect on the Ca2+ responses of cortical neurons induced by AMPA or quisqualate. Meanwhile, the Ca2+ responses of hippocampal neurons induced by glutamate, ACPD or adrenaline, showed only a slight decrease following fucoidan treatment. RT-PCR assays of cortical and hippocampal neurons showed that fucoidan treatment significantly decreased the mRNA expression of NMDA-NR1 receptor and the primer pair for l-type Ca2+ channels, PR1/PR2. Discussion and conclusions: Our data indicate that fucoidan suppresses the intracellular Ca2+ responses by selectively inhibiting NMDA receptors in cortical neurons and l-type Ca2+ channels in hippocampal neurons. A wide spectrum of fucoidan binding to cell membrane may be useful for designing a general purpose drug in future. [ABSTRACT FROM AUTHOR]

Life cycle costs of co-digestion plant of cattle farm manure and locally available freshwater macrophyte C. demersum, marine brown algae F. vesiculosus, and marine green algae U. intestinalis; ratio 5:1) are analysed based on Latvian climatic and economic conditions. Biomass collection from nature and pre-treatment of biomass, biogas production, biogas treatment and utilization in combined heat and power plant are included in the boundaries. The weak points of scenarios are large capital investments, electricity sale price (and the application of feed-in tariff). As naturally grown algae and macrophytes are used, they are also sensitive to weather conditions each year as available amounts of biomass might change and decrease. Net Present Value is positive only for C. demersum with Internal Rate of Return of –14 % and Discounted Payback Period of 11 years. [ABSTRACT FROM AUTHOR]

The study involves development of a green biorefinery process for obtaining fucoidan, laminarin, mannitol, alginate and protein from dry and fresh Fucus vesiculosus and Ascophyllum nodosum using hydrochloric acid and a green extraction solvent. After the extraction of fucoidan which was the targeted biomolecule, an extract and by-product (residual biomass) were obtained. The extract was passed through an ultrafiltration membrane, where fucoidan was obtained in the ultrafiltration retentate while ultrafiltration permeate was analysed for laminarin and mannitol. The residual biomass was used for obtaining alginate using ultrasound (20 kHz, 64 % amplitude and 32 min, optimum parameters for alginate extraction based on our previous study). All the samples, showed good results for alginate, laminarin and mannitol, indicating that the by-products can be utilised using this green extraction process. The comparison of both dry and fresh seaweed is relevant from an industry perspective, as fresh seaweed can directly be used for extraction, avoiding drying which adds significantly to the cost of the process. Life cycle impact assessment of the complete seaweed value chain has been carried out to identify the energy demand and key environmental hotspots. This biorefinery process can be used by industry to improve their processes and utilise the by-products generated efficiently. [ABSTRACT FROM AUTHOR]

Coastal ecosystems have received international interest for their possible role in climate change mitigation, highlighting the importance of being able to assess and predict how changes in habitat distributions and their associated communities may impact the greenhouse gas sink potential of these vegetated seascapes. Importantly, the range and diversity of macrophytes within the vegetated seascape have different capacities to store C within their biomass and potentially sequester C depending on their functional trait characteristics. To bridge the present knowledge gaps in linking macrophyte traits to C storage in tissue, we (1) quantified biomass-bound C stocks within diverse macrophyte communities, separately for soft and hard bottom habitats and (2) explored the links between various traits of both vascular plants and macroalgae and their respective biomass-bound C stocks using structural equation modeling (SEM). We conducted a field survey where we sampled 6 soft bottom locations dominated by aquatic vascular plants and 6 hard bottom locations dominated by the brown algae Fucus vesiculosus in the Finnish archipelago. Macrophyte carbon stocks of hard bottom locations were an order of magnitude higher than those found in soft bottom locations. Biodiversity was associated with aquatic plant carbon stocks through mass ratio effects, highlighting that carbon stocks were positively influenced by the dominance of species with more acquisitive resource strategies, whereas age was the main driver of carbon in the mono-specific macroalgal communities. Overall, our results demonstrate that habitat type and dominating life-history strategies influenced the size of the organism-bound carbon stocks. Moreover, we showed the importance of accounting for the diversity of different traits to determine the drivers underpinning carbon storage in heterogenous seascapes composed of macrophyte communities with high functional diversity. • Changes in macrophyte communities impact C capture through vegetation build-up. • Life-history strategies influenced the size of the organism-bound carbon stocks. • Functional traits provide an in-depth insight on the role of community structure. [ABSTRACT FROM AUTHOR]

Seaweeds are one of the largest producers of biomass in the marine environment and a source of multiple bioactive metabolites with valuable health benefits. Among these, phlorotannins have been widely recognized for their promising bioactive properties. The potential antitumor capacity of Fucus vesiculosus-derived phlorotannins remains, however, poorly explored, especially in gastrointestinal tract-related tumors. Therefore, this work aimed to evaluate the cytotoxic properties and possible mechanisms by which F. vesiculosus crude extract (CRD), phlorotannin-rich extract (EtOAc), and further phlorotannin-purified fractions (F1–F9) trigger cell death on different tumor cell lines of the gastrointestinal tract, using flow cytometry. The results indicate that F. vesiculosus samples exert specific cytotoxicity against tumor cell lines without affecting the viability of normal cells. Moreover, it was found that, among the nine different phlorotannin fractions tested, F5 was the most active against both Caco-2 colorectal and MKN-28 gastric cancer cells, inducing death via activation of both apoptosis and necrosis. The UHPLC-MS analysis of this fraction revealed, among others, the presence of a compound tentatively identified as eckstolonol and another as fucofurodiphlorethol, which could be mainly responsible for the promising cytotoxic effects observed in this sample. Overall, the results herein reported contribute to a better understanding of the mechanisms behind the antitumor properties of F. vesiculosus phlorotannin-rich extracts.

Mechanisms related to the induction of phlorotannin biosynthesis in marine brown algae remain poorly known. Several studies undertaken on fucoid species have shown that phlorotannins accumulate in the algae for several days or weeks after being exposed to grazing, and this is measured by direct quantification of soluble phenolic compounds. In order to investigate earlier inducible responses involved in phlorotannin metabolism, Fucus vesiculosus was studied between 6 and 72 h of grazing by the sea snail Littorina littorea. In this study, the quantification of soluble phenolic compounds was complemented by a Quantitative real-time PCR (qRT-PCR) approach applied on genes that are potentially involved in either the phlorotannin metabolism or stress responses. Soluble phlorotannin levels remained stable during the kinetics and increased significantly only after 12 h in the presence of grazers, compared to the control, before decreasing to the initial steady state for the rest of the kinetics. Under grazing conditions, the expression of vbpo, cyp450 and ast6 genes was upregulated, respectively, at 6 h, 12 h and 24 h, and cyp450 gene was downregulated after 72 h. Interestingly, the pksIII gene involved in the synthesis of phloroglucinol was overexpressed under grazing conditions after 24 h and 72 h. This study supports the hypothesis that phlorotannins are able to provide an inducible chemical defense under grazing activity, which is regulated at different stages of the stress response.

In the course of the ongoing global intensification and diversification of human pressures, the study of variation patterns of biological traits along environmental gradients can provide relevant information on the performance of species under shifting conditions. The pronounced salinity gradient, co‐occurrence of multiple stressors, and accelerated rates of change make the Baltic Sea and its transition to North Sea a suitable region for this type of study. Focusing on the bladderwrack Fucus vesiculosus, one of the main foundation species on hard‐bottoms of the Baltic Sea, we analyzed the phenotypic variation among populations occurring along 2,000 km of coasts subjected to salinities from 4 to >30 and a variety of other stressors. Morphological and biochemical traits, including palatability for grazers, were recorded at 20 stations along the Baltic Sea and four stations in the North Sea. We evaluated in a common modeling framework the relative contribution of multiple environmental drivers to the observed trait patterns. Salinity was the main and, in some cases, the only environmental driver of the geographic trait variation in F. vesiculosus. The decrease in salinity from North Sea to Baltic Sea stations was accompanied by a decline in thallus size, photosynthetic pigments, and energy storage compounds, and affected the interaction of the alga with herbivores and epibiota. For some traits, drivers that vary locally such as wave exposure, light availability or nutrient enrichment were also important. The strong genetic population structure in this macroalgae might play a role in the generation and maintenance of phenotypic patterns across geographic scales. In light of our results, the desalination process projected for the Baltic Sea could have detrimental impacts on F. vesiculosus in areas close to its tolerance limit, affecting ecosystem functions such as habitat formation, primary production, and food supply. [ABSTRACT FROM AUTHOR]

BACKGROUND There is limited information in the literature concerning the feasibility of using algal extracts as natural additives for improvement of the quality and shelf‐life of meat products. Hence, a Fucus vesiculosus extract (FVE) at the concentrations of 250 mg kg‐1 (FVE‐250), 500 mg kg‐1 (FVE‐500) and 1000 mg kg‐1 (FVE‐1000) were added to pork patties with linseed oil oleogel as a fat replacer. RESULTS: Total polyphenol content of FVE was determined to be 20 g phloroglucinol equivalents 100 g‐1 extract. Antioxidant values ranged from 37.5 μmol of Trolox equivalents (TE) g‐1 (FRAP assay) to 2111 μmol TE g‐1 extract (ABTS assay). Regarding oxidation stability, FVE‐1000 showed the lowest values of thiobarbituric acid‐reactive substance and carbonyl content. On the other hand, FVE did not improve color, surface discoloration or odor attributes of patties during storage. Sensory evaluation revealed that there was no significant difference among all studied samples. CONCLUSION: Although FVEs have a high polyphenol content and antioxidant activities, they are not effective oxidation inhibitors for long‐term storage of meat products. Therefore, additional measures or compounds should be considered when FVE is the only antioxidant in meat products. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Stochastic upwelling of seawater in the Baltic Sea from the deep, anoxic bottoms may bring low-pH water rich in CO2 close to the surface. Such events may become more frequent with climate change and ongoing ocean acidification (OA). Photoautotrophs, such as macroalgae, which are important foundation species, have been proposed to benefit from increased carbon availability due to reduced energetic cost in carbon acquisition. However, the exact effects of CO2 fertilization may depend on the ambient light environment, as photosynthesis rates depend on available irradiance. In this experimental study, interacting effects of CO2 addition and irradiance on the habitat-forming macroalga Fucus vesiculosus were investigated during two seasons – winter and summer – in the northern Baltic Sea. Growth rates remained unaffected by CO2 or irradiance during both seasons, suggesting that direct effects of elevated CO2 on mature F. vesiculosus are small. Increases in CO2 affected algal elemental ratios by increasing carbon and decreasing nitrogen content, with resulting changes in the C:N ratio, but only in winter. In summer, chlorophyll a content increased under low irradiance. Increases in CO2 caused a decline in light-harvesting efficiency (decrease in Fv/Fm and α) under high irradiance in summer, and conversely increased α under low irradiance. High irradiance caused increases in the maximum relative electron transport rate (rETRmax) in summer, but not in winter. Differences between winter and summer indicate that F. vesiculosus responses to CO2 and irradiance are season-specific. Increases in carbon content during winter could indicate slightly positive effects of CO2 addition in the long run if the extra carbon gained may be capitalized in growth. The results of this study suggest that increases in CO2, either through upwelling or OA, may have positive effects on F. vesiculosus, but these effects are probably small. [ABSTRACT FROM AUTHOR]

Objectives: To search for novel compounds that will protect neuronal cells under stressed conditions that may help to restore neuronal plasticity. Methods: A model of corticosterone (CORT)-induced stress in human neuroblastoma cells (SH-SY5Y) was used to compare the efficacy of 6 crude extracts and 10 pure compounds (6 polyphenols, 2 carotenoids, 1 amino acid analogue, and 1 known antidepressant drug) to increase neuronal plasticity and to decrease cytotoxicity. Results: Astaxanthin (among pure compounds) and phlorotannin extract of Fucus vesiculosus (among crude extracts) showed a maximum increase in cell viability in the presence of excess CORT. BDNF-VI mRNA expression in SH-SY5Y cells was significantly improved by pretreatment with quercetine, astaxanthin, curcumin, fisetin, and resveratrol. Among crude extracts, xanthohumol, phlorotannin extract (Ecklonia cava), petroleum ether extract (Nannochloropsis oculata), and phlorotannin extract (F. vesiculosus) showed a significant increase in BDNF-VI mRNA expression. CREB1 mRNA expression was significantly improved by astaxanthin, β-carotene, curcumin, and fluoxetine whereas none of the crude extracts caused significant improvement. As an adjunct of fluoxetine, phlorotannin extract (F. vesiculosus), β-carotene, and xanthohumol have resulted in significant improvement in BDNF-VI mRNA expression and CREB1 mRNA expression was significantly improved by phlorotannin extract (F. vesiculosus). Significant improvement in mature BDNF protein expression by phlorotannin extract (F. vesiculosus) and β-carotene as an adjunct of fluoxetine confirm their potential to promote neuronal plasticity against CORT-induced stress. Discussion: The carotenoids, flavonoids, namely quercetine, curcumin, and low molecular weight phlorotannin-enriched extract of F. vesiculosus may serve as potential neuroprotective agents promoting neuronal plasticity in vitro. Graphical abstract: Cascade of events associated with disturbed homeostatic balance of glucocorticoids and impact of phlorotannin extract (F. vesiculosus) and β-carotene in restoring neuronal plasticity. Abbreviation: TrKB, tropomyosin receptor kinase B; P-ERK, phosphorylated extracellular signal-related kinase; PI3K, phosphatidylinositol 3-kinase; Akt, protein kinase B; Ca++/CaMK, calcium/calmodulin-dependent protein kinase; pCREB, phosphorylated cAMP response element-binding protein; CRE, cAMP response elements, CORT, corticosterone; and BDNF; brain-derived neurotrophic factor. [ABSTRACT FROM AUTHOR]

• Cytotoxic activity was investigated for Fucus vesiculosus fucoidan. • The activity was studied against different cells for crude and purified products. • In addition to purity, physicochemical properties affected the cytotoxic activity. • The applied technique has succeeded to produce much bioactive product. • The study reflected a real picture of fucoidan cytotoxic activity. The development of natural-based anti-tumor medicaments has acquired a great interest especially in the last few decades. Hence, cytotoxic activity of different fractions of fucoidan was evaluated. The fractions, produced from the total crude extract of the brown alga Fucus vesiculosus and purified by the recently-developed immobilized cationic dyes at different conditions, had different physicochemical properties and named fucoidan_1, fucoidan_6 and fucoidan_PDD. The activity of these fractions was studied in vitro against different kinds of cancerous mammalian cell lines including MCF-7 and Caco-2 and compared to their effects against skin primary fibroblasts. The results indicated a potent cytotoxic activity with regard to MCF-7 cells, while negligible (>1500 μg mL−1) towards primary fibroblasts. Moreover, higher general toxicity of crude fucoidan indicated that purification process succeeded to remove extraneous, co-extracted, cytotoxic compounds (e.g., polyphenols), which has a strong activity and possible interference in previously-published studies. Furthermore, a correlation was made between the cytotoxic activity and physico-chemical properties of fucoidan fractions, such as the sulfation degree and molecular weight. These findings reflected a real picture and expected low side effects regarding the cytotoxic activity of fucoidan purified by affinity chromatography. [ABSTRACT FROM AUTHOR]

The influence of gelatin from bovine skin on the rheological properties of hydrogels in an extract from the alginate-containing algae Fucus vesiculosus was studied. The shear rate and dynamic mechanical analyses were used to determine the rheological properties. FT-IR spectroscopy showed that the main structural component of the Fucus extract was sodium alginate. The changes of the rheological properties of the extract with the introduction of gelatin are explained using the framework of the alginate–gelatin complexation model. The Fucus extract showed a weakly expressed non-Newtonian behaviour since the flow index in the Ostwald–De Waele equation is 0.91–0.94. The introduction of gelatin (1.0 wt.%) into the extract at 24 °C led to the formation of a hydrogel, whereas the extract itself cannot form a gel with these conditions. Further increasing the concentration of gelatin led to an exponential increase in the yield stress, plastic viscosity and apparent viscosity of the hydrogels. The introduction of gelatin into the Fucus extract at 4 °C led to a non-additive increase in the elastic modulus (G ′), and a decrease in the tan δ of the hydrogels, i.e., strengthening of the elastic properties and weakening of viscous properties in these systems. The changes in the rheological parameters of a Fucus extract after the introduction of gelatin can be explained by an increase in the concentration of triple helices in the macromolecular chains of the gelatin, which are the elastic elements in the 3D mixed gel network. [ABSTRACT FROM AUTHOR]

Laboratory‐scale studies suggest that water‐borne chemical cues released in grazing of marine macroalgae act as info‐chemicals allowing the yet‐undamaged conspecifics to increase their resistance before the actual herbivore attack. The relevance of this finding in natural populations has thus far remained unexplored.We investigated spread of water‐borne herbivore resistance in a field experiment using the littoral foundation species Fucus vesiculosus. We exposed algal genotypes for water‐borne cues in the distances of 0.5 and 2 m from the grazed cue‐emitting genotypes. We measured herbivore resistance with preference experiments and recorded changes in the phlorotannin content. We recorded changes in biomass and length of the genotypes to test whether water‐borne resistance correlates with the grazing damage on the cue‐emitter or incurs costs for the genotypes in terms of reduced growth.In two of our four experimental blocks, induced resistance via water‐borne cues took place and spread to undamaged neighbours that were 2 m distance apart. This provides evidence of water‐borne resistance induction in the wild as well as of small‐scale spatial variation in the spread of induction. The undamaged neighbours induced resistance to a lesser extent than the directly grazed cue‐emitters did, but resistance was consistently expressed among all 26 algal genotypes and independent of the amount of grazing damage on the cue‐emitter. Herbivore resistance correlated negatively with the growth in the grazed cue‐emitting genotypes, while water‐borne resistance was independent of the variation in growth.Our results show, for the first time for marine macroalgae in a natural setting, that information about the increased risk of herbivory can be carried by water‐borne cues and is used to prime or induce defences prior to an actual attack. The results we present furthermore indicate that water‐borne resistance differs quantitatively and qualitatively from the resistance triggered by actively feeding herbivores. Ability to induce resistance prior the herbivore arrival may greatly influence the ability of littoral macroalgae to withstand the generally intense herbivory of marine benthic environments. A plain language summary is available for this article. [ABSTRACT FROM AUTHOR]

Induction of an axenic filamentous‐like callus growth from the brown algae Fucus vesiculosus is described. Different treatments were investigated in various combinations to develop axenic cultures based on identification of surface symbionts via 18S ribosomal RNA. Moreover, viability was confirmed after such processes by 2,3,5‐triphenyl tetrazolium chloride assay that demonstrated an average viability of 29%, relative to nonsterilized explants. After six weeks of a phototrophic cultivation on artificial sea water‐12‐nitrilotriacetic acid (0.5% w/v agar), a filamentous‐like callus growth was observed, which was identified genetically through its mitochondrial DNA after subculturing. Achievement of confirmed marine callus cultures might enrich old previously established blue biotechnology techniques and open new chances for cultivation of brown algae for production of good manufacturing practice‐compliant bioproducts. [ABSTRACT FROM AUTHOR]

Sandy beach food webs depend heavily upon marine organic input, such as macroalgae, as internal organic matter productivity is low. The fate, however, of this marine organic material (termed wrack) after being deposited onto the beach and its relation to pioneer vegetation, consisting of annual and perennial beach plants, needs to be further elucidated. In particular, the effect of various drivers, such as wrack burial and macroinvertebrate presence, on wrack decomposition is largely unknown on sandy beaches. Also, the subsequent effects of decomposition-driven nitrogen and phosphorus availability on beach pioneer plant growth are not yet understood. We performed a mesocosm experiment manipulating Fucus vesiculosus wrack access to the supratidal amphipod Talitrus saltator , and used Cakile maritima and Elytrigia juncea as phytometers to estimate decomposition-driven, wrack-derived nutrient supply. Buried wrack had a strong positive effect (2–3 fold increase) on plant mass, N and P content of C. maritima compared to surface wrack, while effects on E. juncea were largely absent. In addition, macroinvertebrate-facilitated decomposition was important for increasing nutrient availability, but this did not result in an increase in plant growth. We conclude that the burial of wrack by a thin layer of sand is a crucial driver of beach pioneer plant growth, which is most likely due to an increase in moisture availability. This supports the importance of management practices that allow deposited wrack to remain and be buried on the sandy beach for a long period of time, which will have positive effects on beach pioneer plant growth and possibly embryo dune formation. • Wrack burial and macroinvertebrate presence effects on plant growth were studied. • Sand burial of wrack had a strong positive effect on beach pioneer plant growth. • Macroinvertebrate presence affected plant nutrient dynamics, but not growth. • Wrack burial drives beach pioneer plant growth by enhancing sediment moisture. • Allow wrack to be buried on the beach in support of the sandy beach ecosystem [ABSTRACT FROM AUTHOR]

Biofouling by marine organisms can result in a variety of negative environmental and economic consequences, with decontamination procedures remaining problematic, costly and labour-intensive. Here, we examined the efficacy of direct steam exposure to induce mortality of selected biofouling species: Mytilus edulis ; Magallana gigas ; Semibalanus balanoides ; Fucus vesiculosus ; and an Ulva sp. Total mortality occurred at 60-sec of steam exposure for M. edulis and juvenile M. gigas , at 30-sec for S. balanoides , while 300-sec was required for adult M. gigas. Application of steam reduced the biomass of F. vesiculosus and significantly reduced Ulva sp. biomass, with complete degradation being observed for Ulva sp. following 120-sec of exposure. Accordingly, it appears that steam exposure can cause mortality of biofouling organisms through thermal shock. Although preliminary, our novel and promising results suggest that steam applications could potentially be used to decontaminate niche areas and equipment. • Steam exposure can cause mortality and biodegradation through thermal shock. • Direct exposure to steam caused total mortality of biofouling bivalve species. • Complete mortality can be achieved with short exposure times of ≤60 sec. • Larger-bodied bivalves, e.g. adult Magallana gigas , required longer exposure times. • Steam significantly reduced the biomass of Ulva sp. [ABSTRACT FROM AUTHOR]

Pesisir Barat Regency in Lampung has abundant marine biological wealth that has not been widely known and utilized by the community, one of them is macro algae. The objectives of the research were to identify the types of macro algae and to explains the potential use of macro algae in the Pesisir Barat Lampung Region. The study used cruise method. The findings were identified by experts to validate the results of classification, morphology, and qualitative studies regarding the potential use and benefits of macro algae. From the results of this study, 15 species of macro algae were found on Tanjung Setia Beach included; 3 species of green algae (Chlorophyta) consist of Halimeda opuntia L., Caulerpa racemosa F., Ulva lactuca L .; 7 species of brown algae (Phaeophyta) consist of Padina pavonica L., Padina australis H., Sargassum vulgare C.A., Sargassum polycystum C.A., Turbinaria ornata J.A., Turbinaria ornata J.A., Fucus vesiculosus L.; and 5 species of red algae (Rhodophyta), consist of Corallina officinalis L., Gigartina pistilla S., Gigartina disticha S., Gracilaria verrucosa, H., Rhodymenia pseudopalmat J.V.L.The benefits of this research for society to provide insight into the potential use of macro algae which can be utilized in many fields. For students, provide information on the biodiversity of macro algae in the sea. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Dried Fucus vesiculosus , is an efficient biosorbent for Zn uptake from wastewater. • Zn adsorption mechanisms are ion exchange and coordination. • The carboxylic groups from algae alginate are responsible for Zn binding at low pH. • Zn coordinates with 5 and 6 O at distances between 1.98–2.03 Å. Abstract This study presents a multifaceted approach of Zn adsorption onto dry Fucus vesiculosus originating from the Irish Sea. Metal chemistry as well as algae surface charge properties were characterized before adsorption. Zn adsorption tests were run as function of: pH, algae concentration and metal source. A comparison with Co, Cd, and Cu adsorption – in mono-ion solutions was also performed. Adsorption kinetics, fitted with pseudo-first order (PFO) and pseudo-second order (PSO) kinetic model, allowed the uptake parameters to be found and a comparison of kinetic rates. Synchrotron X-Ray-Florescence and X-Ray Absorption Spectroscopy measurements of Zn on algae after exposure permitted the extraction of direct information about Zn spatial distribution and bonding environment. The results showed that the carboxylic groups are the ones involved in the heterogeneously distributed Zn adsorption at low pH, Zn being coordinated with 5–6 O at bond distances varying from 1.98 to 2.03 Å - as in Zn alginate. Synchrotron results provide confirmation that, relative to Zn, alginate is one of the main algae components responsible for metal binding. [ABSTRACT FROM AUTHOR]

Objectives: To determine whether a fucoidan extract reduced insulin resistance and/or altered other cardiometabolic markers in an obese, nondiabetic population. Design: Single-site, double-blinded, placebo-controlled, randomized controlled trial. Setting/Location: Hobart, Tasmania, Australia. Subjects: Eligible subjects were obese, with no history of diabetes, and ages between 18 and 65 years. Interventions: Subjects were randomly assigned, in even blocks of 10, to either active fucoidan 500 mg or placebo capsules twice daily for 90 days, with identical measurements performed at baseline and follow-up. Outcome measures: The primary outcome was insulin resistance, defined by the homeostasis model of assessment (HOMA) values. Secondary outcomes were lipid profile, glycosylated hemoglobin, urea electrolytes and creatinine, liver function tests, full/complete blood count, fasting insulin, fasting glucose, quantitative insulin sensitivity check index, glucose area under the curve, weight, body mass index, waist circumference, and systolic and diastolic blood pressure. The trial was registered with the Australian New Zealand Clinical Trial Registry (ACTRN12614000495628) and the Therapeutic Goods Administration (2014/0348), and was funded by Marinova Pty. Ltd. Results: There were no differences in the 90-day outcome measures between placebo and active treatment in the intention-to-treat-analysis (n = 35 for active, n = 37 for placebo). The mean change in HOMA scores was 0 for the placebo and −0.1 for the active groups (p = 0.73). Self-reported adherence was high, consistent with capsule counting at the conclusion of the trial. Conclusions: Fucoidan taken twice daily for a period of 90 days did not markedly affect insulin resistance or other measured parameters of cardiometabolic health in an obese, nondiabetic cohort. This could be due to an intrinsic lack of efficacy, lower than measured adherence, or because longer therapy and/or higher baseline insulin resistance are required to exert a significant effect. [ABSTRACT FROM AUTHOR]

Populations at range margins of marine organisms are at the front line of climate-induced changes in abiotic factors and are thus particularly susceptible. Especially, macroalgae that are externally reproducing rely on optimal environmental conditions for gamete release and subsequent fertilisation. However, the effect of climate change–forced decrease in salinity on these critical life stages has been largely overlooked. We tested the impact of forecasted hyposaline conditions on a marginal population of the rockweed Fucus vesiculosus growing at 5.8 PSU on the Finnish coast of the Baltic Sea. We incubated individuals with receptacles for at least seven days at 2.5, 4.1, 5.8, and 7.2 PSU and determined their gamete release and subsequent fertilisation success. We further tested sperm performance at 3.5, 5.0, and 6.1 PSU. Salinity of 2.5 PSU, which is predicted to occur in the region by the end of this century, reduced egg release. In contrast, sperm and antheridia release were not consistently affected by the different salinities, but the size of sperm swells at 3.5 PSU. Because fertilisation success was drastically reduced at 2.5 and 4.1 PSU, we suggest that sperm performance was compromised such that sperm dysfunction hampered fertilisation success. Our results demonstrate that the forecasted hyposalinity negatively affects egg release and sexual reproduction in F. vesiculosus at its northern distribution limit. This macroalga can probably only withstand the future decrease in salinity when populations proliferate via asexual reproduction. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate a nutraceutical combination containing polyphenols extracted from Ascophyllum nodosum and Fucus vesiculosus and chromium picolinate on glyemic status; secondary outcomes were considered the changes on endothelial markers. We randomized 65 dysglycemic patients to placebo or the nutraceutical agent for 6 months. We evaluated fasting plasma glucose (FPG), postprandial plasma glucose (PPG), HbA1c , fasting plasma insulin, homeostatic model assessment (HOMA) index, high sensitivity C-reactive protein (Hs-CRP), tumor necrosis factor-α (TNF-α), and adhesion molecules. At baseline and at 3 and 6 months, all patients underwent an oral glucose tolerance test. We recorded a reduction of HbA1c , FPG, PPG, and HOMA-IR compared with placebo (p < 0.05). After 6 months, 18.2% of patients retuned to a normal glycemic status in the nutraceutical group versus 0 patients in placebo group (p < 0.05); 69.7% were classified as impaired fasting glycemia and 12.1% as impaired glucose tolerance in the nutraceutical group versus 17.2% and 82.8 in placebo group (p < 0.01) for both. A reduction of Hs-CRP and TNF-α was recorded with the nutraceutical. The administration of a nutraceutical combination containing A. nodosum and F. vesiculosus can be helpful in improving insulin sensitivity and glycemic status. Larger randomized studies are required to confirm the positive effects of these agents. [ABSTRACT FROM AUTHOR]

Over recent decades, the neophyte Fucus evanescens has extended eastwards along the salinity gradient within the Baltic Sea, indicating gradual adaptation to low salinity conditions. To find out whether F. evanescens can migrate further into the Baltic Sea and potentially become a competitor to the native F. vesiculosus, the acclimation potentials of different F. evanescens and F. vesiculosus populations were investigated with respect to habitat salinity. For both species, pigmentation, water content, and photosynthetic rate were measured under laboratory and field conditions. The instantaneous measurement data and incubation experiment did not show clear differences in the measured photosynthetic parameters between different salinity levels (6–20), or between species. Maximum likelihood phylogenetic analyses of the nuclear marker PDI (a putative protein disulfide isomerase) separated F. vesiculosus and F. evanescens into well-defined groups supporting the hypothesis that the two very similar species do not represent different morphotypes of the same species/gene pool. These findings indicate that – at least for the vegetative stage of F. evanescens – salinity may not be a limiting factor for a further spread into the Baltic Sea. [ABSTRACT FROM AUTHOR]

Fucus vesiculosus is common both on the tidal coasts of the North Atlantic and in the Baltic Sea, where it has adapted to low salinity and nontidal conditions over the last 7000 years. During the late 1970s and early 1980s, extensive declines of F. vesiculosus populations were reported in the Baltic Proper, mainly attributed to high nutrient loads. During the past 30–40 years, considerable efforts have been made to reduce nutrient runoff to coastal areas but few successful initiatives to restore F. vesiculosus populations have been performed. In this paper, we present how substratum manipulation, i.e. clean rocky surfaces, brushing rocks, Hildenbrandia rubra cover and different filamentous algae, as well as different algal exudates, affect the recruitment and survival of juvenile F. vesiculosus. Further, we show through a 5-year field experiment that it will take at least 4–5 years to reach reproductive age for F. vesiculosus in the Baltic Sea. We also present transplantation studies from two different areas, showing that epiphytic load, light, grazing and type of substratum are some of the factors that need to be taken into consideration in order to achieve successful restoration of F. vesiculosus. [ABSTRACT FROM AUTHOR]

Abstract This study investigated the neuroprotective activities of five different fucoidan samples with different chemical compositions prepared from Fucus vesiculosus (FE, FF, and S) and Undaria pinnatifida (UE and UF) to determine if they reduced aggregation or cytotoxicity of Aβ 1–42 in neuronal PC-12 cells. Only fucoidans S, UE, and UF showed anti-aggregation effects against Aβ 1–42 , as determined using Thioflavin T (ThT) fluorometric fibrillisation kinetics and transmission electron microscopy (TEM) of fibril morphology. However, all five fucoidan samples reduced the cytotoxicity of both Aβ 1–42 and hydrogen peroxide in neuronal PC-12 cells and demonstrated inhibition of apoptosis induced by Aβ 1–42. Three fucoidan samples (FF, UE and UF) showed significant activity in enhancing neurite outgrowth. Fucoidan from different seaweed sources and with varying chemical compositions demonstrate a range of neuroprotective activities that may have potential to alter Aβ 1–42 neurotoxicity in Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Abstract Mesopredators must contend with both top-down (predation pressure by top predators) and bottom-up (food availability) drivers when selecting habitat. We studied the distribution and trophic dynamics of an abundant mesopredator (the three-spined stickleback; Gasterosteus aculeatus) in three habitats of differing complexity: a macroalgal bed (Fucus vesiculosus), a seagrass meadow (Zostera marina), and a sand flat. We found that stickleback abundance and food availability were highest in the macroalgae, intermediate in the seagrass, and very low in the sand flat. We then tested in situ predation pressure on isopods and amphipods by tethering live prey in the three habitats. Predation on amphipods was very high in early summer, when it was highest in the sand flat, intermediate in the seagrass, and lowest in the macroalgae. However, small-scale within-habitat differences in physical complexity (shoot density) or location (interior vs. edge) did not affect predation rates. Predation rates on amphipods decreased with prey size, but predation on isopods was always low. Laboratory experiments using amphipod prey and stickleback predators supported the patterns observed in the field, where predation success was highest in the sand and lowest in the Fucus. Overall, sticklebacks were more abundant in, and preferentially chose, the two habitats with highest structural complexity (the macroalgae bed and seagrass meadow), potentially trading off low predation success for higher food availability and increased shelter from top predators. These results confirm the critical importance of these structured habitats for coastal trophic networks. Highlights • Sticklebacks were more abundant in, and preferred, complex habitats. • Complex habitats also provided higher food availability. • Stickleback predation success decreased with increasing habitat complexity. • Sticklebacks may trade-off predation success for food availability and shelter. [ABSTRACT FROM AUTHOR]

The important role of macroalgal canopies in the oceanic carbon (C) cycle is increasingly being recognized, but direct assessments of community productivity remain scarce. We conducted a seasonal study on a sublittoral Baltic Sea canopy of the brown alga Fucus vesiculosus, a prominent species in temperate and Arctic waters. We investigated community production on hourly, daily, and seasonal timescales. Aquatic eddy covariance (AEC) oxygen flux measurements integrated ~ 40 m2 of the seabed surface area and documented considerable oxygen production by the canopy year‐round. High net oxygen production rates of up to 35 ± 9 mmol m−2 h−1 were measured under peak irradiance of ~ 1200 μmol photosynthetically active radiation (PAR) m−2 s−1 in summer. However, high rates > 15 mmol m−2 h−1 were also measured in late winter (March) under low light intensities < 250 μmol PAR m−2 s−1 and water temperatures of ~ 1°C. In some cases, hourly AEC fluxes documented an apparent release of oxygen by the canopy under dark conditions, which may be due to gas storage dynamics within internal air spaces of F. vesiculosus. Daily net ecosystem metabolism (NEM) was positive (net autotrophic) in all but one of the five measurement campaigns (December). A simple regression model predicted a net autotrophic canopy for two‐thirds of the year, and annual canopy NEM amounted to 25 mol O2 m−2 yr−1, approximately six‐fold higher than net phytoplankton production. Canopy C export was ~ 0.3 kg C m−2 yr−1, comparable to canopy standing biomass in summer. Macroalgal canopies thus represent regions of intensified C assimilation and export in coastal waters. [ABSTRACT FROM AUTHOR]

The principle objective of this study was to research the variation of fertility in Fucus vesiculosus across its growth band in the middle intertidal. After collecting twenty samples each at the upper and lower limits of the band, fertility was measured as the ratio of reproductive ends to nonreproductive ends. This study found that F. vesiculosus fertility at the lower limit of the middle intertidal is significantly higher than that at the upper limit. Although the fertility is higher, the density of both the number of holdfasts and total ends, apical and gamete, are significantly lower at the lower limit than at the upper limit of the growth band. [ABSTRACT FROM AUTHOR]

Purpose: Fibrin clot is essential for post-operative abdominal adhesion formation. Fucoidans, sulfated polysaccharides, inhibit fibrin clot formation. In addition, they inhibit inflammation and fibrosis, which also play important roles in adhesion formation. The purpose of this study was to evaluate fucoidans’ potential for inhibiting post-operative abdominal adhesions and measure their effects on systemic coagulation parameters when administered intraperitoneally (IP). Methods and materials: Female Sprague Dawley rats were studied. A 2.5x2.5cm full thickness segment of abdominal wall was excised. The skin edges were approximated. This model induces extensive adhesions and allows objective quantitation. Three fucoidans were evaluated- Sigma Fucoidan Crude (SFC), Fucus vesiculosis 95% (Sigma) and, Peridan. One protocol involved continuous infusion into the abdomen from a subcutaneous osmotic pump. Alternatively, boluses of the solutions were injected IP at the end of the operation. Rats were sacrificed a week later. Adhesion extent was scored. Systemic coagulation effects of fucoidans were also evaluated. INR and aPTT were measured following IP injection of the fucoidan solutions and after 7 days of continuous infusion. Results: Animals given a continuous infusion of either SFC or Peridan yielded adhesion reduction of 80 to 90% from control. Bolus Peridan had no discernable influence on adhesion formation, but a single bolus of SFC caused significant adhesion reductions. Peridan resulted in prompt aPTT elevations which fell to nearly normal by 5 hours. The maximum peak value after SFC injection was seen in 15 hours. The maximal INR elevations were around 2. Measurement of INR and aPTT after a week of continuous infusion of either Peridan or SFC, were always in the normal control range. The third agent, Sigma, frequently yielded intraperitoneal infection found at autopsy. Conclusions: These findings indicate that selected fucoidans infused intraperitoneally for a week after abdominal operations reduce adhesion extent by up to 90%. [ABSTRACT FROM AUTHOR]

Fucoidans, sulfated polysaccharides found in cell walls of brown algae, are considered as a promising antimicrobial component for various applications in medicine and the food industry. In this study, we compare the antibacterial properties of two fractions of fucoidan from the brown algae Fucus vesiculosus gathered in the littoral of the Barents Sea and sampled at different stages of purification. The crude fraction of fucoidan was isolated from algae by extraction with aqueous ethanol and sonication. The purified fraction was obtained by additional treatment of the crude fraction with a solution of calcium chloride. The structural features of both fractions were characterized in detail and their antibacterial effects against several Gram-positive and Gram-negative bacteria were compared by photometry, acridine orange staining assay, and atomic force microscopy. Fucoidan inhibited growth in all of the above microorganisms, showing a bacteriostatic effect with minimum inhibitory concentrations (MIC) in the range between 4 and 6 mg/mL, with E. coli being the most sensitive to both fractions. Changes in the chemical composition after treatment of the crude fraction with a solution of calcium chloride led to a decrease in the content of sulfates and uronic acids and diminished antibacterial activity.

Metabolic syndrome (MetS) is a global public health problem affecting nearly 25.9% of the world population characterised by a cluster of disorders dominated by abdominal obesity, high blood pressure, high fasting plasma glucose, hypertriacylglycerolaemia and low HDL-cholesterol. In recent years, marine organisms, especially seaweeds, have been highlighted as potential natural sources of bioactive compounds and useful metabolites, with many biological and physiological activities to be used in functional foods or in human nutraceuticals for the management of MetS and related disorders. Of the three groups of seaweeds, brown seaweeds are known to contain more bioactive components than either red and green seaweeds. Among the different brown seaweed species, Ascophyllum nodosum and Fucus vesiculosus have the highest antioxidant values and highest total phenolic content. However, the evidence base relies mainly on cell line and small animal models, with few studies to date involving humans. This review intends to provide an overview of the potential of brown seaweed extracts Ascophyllum nodosum and Fucus vesiculosus for the management and prevention of MetS and related conditions, based on the available evidence obtained from clinical trials.

The mechanisms of trace element uptake by seaweeds are still unknown, despite being key to understand the impact of pollution in coastal environments. This knowledge gap, in addition to the lack of standardization, have also hindered the use of seaweeds to monitor seawater pollution. To address these shortcomings, we tested the use of devitalization as a pre-exposure treatment for brown seaweed transplants, and we compared devitalized and fresh transplants to gain some insights into the mechanisms of element uptake. We exposed four types of Fucus vesiculosus transplants in 6 sites for 4, 8 and 20 days: fresh and devitalized (dried or boiled) algal segments held in mesh bags, and whole algal thalli imitating natural conditions. We then determined he concentrations of 11 trace elements in the algal tissues. The element concentrations were highest in the devitalized transplants, but the material lost consistency and weight throughout the exposure period, limiting their use to short periods. We proposed several factors that may contribute to the different accumulation patterns between treatments, and examined the implications for the uptake mechanisms, revealing that two of the most important are surface adsorption of sediment particles and chemical bounds to extracellular components. [Display omitted] • We compared the elemental uptake by fresh and devitalized seaweed transplants. • Most of the material in devitalized transplants was lost during the exposure period. • Devitalized samples had higher elemental uptake for most trace elements. • Physicochemical changes on the seaweeds' surface contribute to the increased uptake. • Extracellular chemical binding and physical adsorption are relevant uptake pathways. [ABSTRACT FROM AUTHOR]

The functional trait approach focuses on the diversity of species characteristics, and can reveal much more about community functioning and trophic structure, compared to classical biodiversity concepts. In this study, we assessed large- and small-scale patterns in the functional traits of invertebrate communities associated with the marine macroalga Fucus vesiculosus. Large-scale comparisons were done across coastal areas representing different water quality (good, moderate, and poor) and small-scale comparisons across communities from sites with different exposures (sheltered, exposed) within the areas. Functional richness differed between areas of different water quality, with higher richness generally observed in areas with clearer waters. On a smaller scale, functional richness and dispersion were highest at sheltered sites, whereas the effect of exposure on functional divergence varied between study areas. Community trait composition differed among areas of different water quality with opportunistic traits becoming more prevalent in areas in poorer state. For example, community-weighted body sizes differed between areas and the smallest body sizes were observed in areas with moderate or poor water quality. The results illustrate how faunal traits within the same habitat type can differ geographically and how the functioning of communities may change due to anthropogenic pressures and natural drivers at different scales. • Functional richness was highest in areas with high water quality. • Functional diversity was higher at sheltered than exposed sites. • Opportunistic traits became more prevalent in areas with poorer water quality. • Community body sizes were smallest in areas with moderate or poor water quality. [ABSTRACT FROM AUTHOR]

The antidiabetic activity and underlying mechanisms of Fucus vesiculosus polysaccharide (FVP) were studied in type 2 diabetic rats. Our results exhibited that FVP intervention reversed body weight loss, alleviated hyperglycemia and insulin resistance in diabetic rats. FVP also had the potential to ameliorate dyslipidemia, liver and kidney dysfunction, decrease oxidative stress, promote glycogen synthesis, and boost short-chain fatty acid production and total bile acid excretion. 16S rRNA gene sequencing analysis suggested that FVP interfered with the gut microbiota in a beneficial manner. Moreover, RT-qPCR results demonstrated that the antidiabetic activity of FVP in connection with the acceleration of blood glucose absorption and glycogen synthesis, the inhibition of gluconeogenesis, and the regulation of lipid metabolism in the liver. These findings suggested that FVP had antidiabetic effects on high-fat diet and STZ-induced diabetic rats and could be a potential resource for treating type 2 diabetes mellitus. [Display omitted] • FVP promoted glycogen storage in diabetic rats. • FVP enhanced bile acid excretion in diabetic rats. • FVP regulated gut microbiota in diabetic rats. • FVP regulated gene expression related to glucose and lipid metabolism in diabetic rats. [ABSTRACT FROM AUTHOR]

Metabolic syndrome is characterized by the coexistence of different metabolic disorders which increase the risk of developing type 2 diabetes mellitus and cardiovascular diseases. Therefore, metabolic syndrome leads to a reduction in patients’ quality of life as well as to an increase in morbidity and mortality. In the last few decades, it has been demonstrated that seaweeds exert multiple beneficial effects by virtue of their micro- and macronutrient content, which could help in the management of cardiovascular and metabolic diseases. This review aims to provide an updated overview on the potential of brown seaweeds for the prevention and management of metabolic syndrome and its associated diseases, based on the most recent evidence obtained from in vitro and in vivo preclinical and clinical studies. Owing to their great potential for health benefits, brown seaweeds are successfully used in some nutraceuticals and functional foods for treating metabolic syndrome comorbidities. However, some issues still need to be tackled and deepened to improve the knowledge of their ADME/Tox profile in humans, in particular by finding validated indexes of their absorption and obtaining reliable information on their efficacy and long-term safety.

Due to their large spectrum of bioactive properties, much attention has recently been drawn to phlorotannins—i.e., phenolic compounds characteristic from brown macroalgae. This study aimed to evaluate the antioxidant and anti-inflammatory properties of F. vesiculosus phlorotannin extracts and purified fractions. Overall, the crude extract and its ethyl acetate fraction (EtOAc) showed good radical scavenging activity, particularly towards nitric oxide (NO•). Subsequent subfractions of EtOAc (F1 to F9) with different molecular weights were then shown to inhibit lipopolysaccharide-induced NO• production in macrophages, with stronger effects being observed for fractions of lower MWs. Of the three intracellular markers analyzed, inducible NO• synthase showed the highest sensitivity to almost all the phlorotannin-rich samples, followed by interleukin 1β and cyclooxygenase 2, which was only inhibited by F2. Furthermore, this subfraction inhibited the phosphorylation and degradation of inhibitory protein κBα, thus preventing the activation of NF-κB and blocking the inflammatory cascade at the transcriptional level. This sample was characterized by the presence of a major compound with a deprotonated molecular ion at m/z 507 with a fragmentation pattern coherent with that of a phlorotannin derivative. Overall, this work unveiled some of the mechanistic aspects behind the anti-inflammatory capacity of phlorotannins from F. vesiculosus, endorsing its use as a possible natural source of anti-inflammatory compounds.

Fucus vesiculosus is a brown macroalgae used in food and generally considered safe to be consumed, according to EU Directive (EC 258/97). The aim of this study is to analyze the effect of food preparation on F.vesiculosus of different origins on what concerns its chemical constituents and final bioactivities. The aqueous extract of the seaweeds were obtained at different temperatures, similar to food preparation and then purified by SPE. The compound identification was carried out by Liquid Chromatography High Resolution Mass Spectrometry (LC-HRMS/MS) and algae extracts microstructure were observed by Scanning Electron Microscopy (SEM). The activities were determined by using antioxidant activity, inhibition of acetylcholinesterase (AChE) and 3-hidroxi-3-methyl-glutaril-CoA (HMG-CoA) reductase (HMGR) together with Caco-2 cells line simulating the intestinal barrier. The activity of AChE and the HMGR were inhibited by the extracts giving IC50 values of 15.0 ± 0.1 µg/mL and 4.2 ± 0.1 µg/mL, respectively and 45% of the cholesterol permeation inhibition. The main compounds identified were phlorotannins and peptides derivatives. The mode of preparation significantly influenced the final bioactivities. Moreover, the in vitro results suggest that the preparation of F. vesiculosus as a soup could have hypercholesterolemia lowering effect.

The brown alga Fucus vesiculosus is common to the intertidal zones of the Baltic Sea, where it is exposed to high fouling pressures by microorganisms. Our previous studies showed, repeatedly, the consistent antimicrobial activity of F. vesiculosus crude extracts against human pathogens, while untargeted metabolomics analyses have revealed a variety of metabolites. In this study, we applied the UPLC-QToF-MS/MS-based “bioactive molecular networking” (BMN) concept on the most bioactive n-hexane and n-butanol subextracts of Baltic F. vesiculosus coupled with in silico dereplication tools to identify the compounds responsible for antimicrobial activity. The first antimicrobial cluster identified by BMN was galactolipids. Our targeted isolation efforts for this class led to the isolation of six monogalactosyldiacylglycerol (MGDG) derivatives (1–6) and one digalactosyldiacylglycerol (DGDG, 7). The MGDGs 5 and 6 and the DGDG 7 exhibited activity against Staphylococcus aureus. The second compound class with high bioactivity was phlorotannins. In particular, phlorethol-type phlorotannins showed high correlations with antimicrobial activity based on the BMN approach, and two phlorotannins (8–9) were isolated. This study shows that antimicrobial components of F. vesiculosus reside in the algal cell walls and membranes and that BMN provides a complementary tool for the targeted isolation of bioactive metabolites.

The fungal genus Pyrenochaetopsis is commonly found in soil, terrestrial, and marine environments, however, has received little attention as a source of bioactive secondary metabolites so far. In a recent work, we reported the isolation and characterization of three new anticancer decalinoyltetramic acid derivatives, pyrenosetins A–C, from the Baltic Fucus vesiculosus-derived endophytic fungus Pyrenochaetopsis sp. FVE-001. Herein we report a new pentacyclic decalinoylspirotetramic acid derivative, pyrenosetin D (1), along with two known decalin derivatives wakodecalines A (2) and B (3) from another endophytic strain Pyrenochaetopsis FVE-087 isolated from the same seaweed and showed anticancer activity in initial screenings. The chemical structures of the purified compounds were elucidated by comprehensive analysis of HR-ESIMS, FT-IR, [α]D, 1D and 2D NMR data coupled with DFT calculations of NMR parameters and optical rotation. Compounds 1–3 were evaluated for their anticancer and toxic potentials against the human malignant melanoma cell line (A-375) and the non-cancerous keratinocyte cell line (HaCaT). Pyrenosetin D (1) showed toxicity towards both A-375 and HaCaT cells with IC50 values of 77.5 and 39.3 μM, respectively, while 2 and 3 were inactive. This is the third chemical study performed on the fungal genus Pyrenochaetopsis and the first report of a pentacyclic decalin ring system from the fungal genus Pyrenochaetopsis.

In recent years, there has been a growing interest in natural antioxidants as replacements of synthetic compounds because of increased safety concerns and worldwide trend toward the usage of natural additives in foods. One of the richest sources of natural antioxidants, nowadays largely studied for their potential to decrease the risk of diseases and to improve oxidative stability of food products, are edible brown seaweeds. Nevertheless, their antioxidant mechanisms are slightly evaluated and discussed. The aims of this study were to suggest possible mechanism(s) of Fucus vesiculosus antioxidant action and to assess its bioactivity during the production of enriched rye snacks. Chemical and cell-based assays indicate that the efficient preventive antioxidant action of Fucus vesiculosus extracts is likely due to not only the high polyphenol content, but also their good Fe2+-chelating ability. Moreover, the data collected during the production of Fucus vesiculosus-enriched rye snacks show that this seaweed can increase, in appreciable measure, the antioxidant potential of enriched convenience cereals. This information can be used to design functional foods enriched in natural antioxidant ingredients in order to improve the health of targeted consumers.

Marine algae represent a prolific source of filamentous fungi for bioprospecting. In continuation of our search for new anticancer leads from fungi derived from the brown alga Fucus vesiculosus, an endophytic Pyrenochaetopsis sp. FVE-001 was selected for an in-depth chemical analysis. The crude fungal extract inhibited several cancer cell lines in vitro, and the highest anticancer activity was tracked to its CHCl3−soluble portion. A bioactivity-based molecular networking approach was applied to C18-SPE fractions of the CHCl3 subextract to predict the bioactivity scores of metabolites in the fractions and to aid targeted purification of anticancer metabolites. This approach led to a rapid isolation of three new decalinoylspirotetramic acid derivatives, pyrenosetins A−C (1−3) and the known decalin tetramic acid phomasetin (4). The structures of the compounds were elucidated by extensive NMR, HR-ESIMS, FT-IR spectroscopy, [α]D and Mosher’s ester method. Compounds 1 and 2 showed high anticancer activity against malignant melanoma cell line A-375 (IC50 values 2.8 and 6.3 μM, respectively), in line with the bioactivity predictions. This is the first study focusing on secondary metabolites of a marine-derived Pyrenochaetopsis sp. and the second investigation performed on the member of the genus Pyrenochaetopsis.