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Host‐related microbiota are critically important for the adaptation/acclimation of hosts to changing environments, but how environmental factors and host characteristics shape the microbial communities remains largely unknown. We investigated the effects of temperature on habitat‐forming macroalgae and their associated bacterial communities. Three Sargassum species (S. horneri, S. fusiforme, and S. thunbergii) and seawater samples were sampled in Gouqi Island, China, and these macroalgal samples were incubated at different temperatures (10, 20, and 27°C) for 7 d. Bacterial communities were identified from the 16S rRNA gene V3–V4 regions. The algae‐associated bacterial communities of the field samples were significantly different from seawater, implying host specificity. During laboratory incubation, decreased physiological status (photosynthetic rate and oxidative stress response) was detected for all the species at 10°C, especially with regard to S. horneri and S. fusiforme. For each host, associated bacterial communities at 20 and 27°C clustered closely, and these were separated from samples at 10°C based on constrained PCoA analyses. Permutational multivariate analysis of variance revealed that algae‐associated bacterial communities were more affected by host species (23.3%) than by temperature (2.48%) during laboratory incubation. The changes in bacterial community composition may be influenced by algae metabolites, which should be tested in a future study. These results further contribute to our understanding of algal microbiome changes in response to environmental changes. [ABSTRACT FROM AUTHOR]

The objective of this research was to evaluate a nutritional strategy based on the consumption of a fucoidan extract from brown algae Lessonia trabeculata to control oxidative stress in experimental alloxan-induced insulin-dependent diabetes mellitus rats. Over 30 days, 75, 100, and 125 mg kg−1 of body weight of fucoidan doses were administered and both positive and negative control (n = 5 per group). Serum, liver, pancreas, and kidney biochemical indicators of oxidative stress improvement were evaluated. Measures included lipid peroxidation, superoxide dismutase and catalase activity, and antioxidant activity by assessment of free radical scavenging power and histopathological changes. The results showed an increase in the activity of antioxidant enzymes while reducing oxidative damage (lipid peroxidation index) in serum (p ≤ 0.05) and tissues (p ≤ 0.05). Further, no liver necrosis was observed in treated groups, unlike the Type 1 diabetes positive control group that presented mild necrosis and moderate congestion. In the pancreas, treated rats presented mild oedema, while the positive control group showed moderate oedema. A significant protective effect against oxidative stress caused by alloxan-induced diabetes was found in this model, therefore it can be concluded that fucoidan extracted from the Lessonia trabeculata algae could be considered a good functional compound for the control of oxidative stress in diabetic patients. Because diabetes is such a widespread public health issue, developing fucoidan-based products could be a natural way to improve patients' quality of life. [ABSTRACT FROM AUTHOR]

The fronds of the brown alga Eisenia bicyclis are regarded as healthy foods and are used as skin care agents because they are rich in dietary fibres, minerals, and antioxidant compounds. However, E. bicyclis stems have been overlooked thus far. In this study, we determined the in vitro antioxidant and antiglycation properties of E. bicyclis stems and their dietary effects on mice fed a high-sucrose and low-fibre diet. The total phenolic content, 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity, ferric-reducing power, and antiglycation activity of the E. bicyclis stem-aqueous extract solution were higher than those of the fronds. The diet containing 5% (w/w) dried E. bicyclis stems increased excretion frequency and faecal and caecal weight and decreased plasma cholesterol levels. The abundance of Bacteroidaceae family and Akkermancsia muciniphila-, Bacteroides acidifaciens-, Phocaeicola vulgatus-, and Parabacteroides goldsteinii-like bacteria increased in E. bicyclis stem-fed mice. These results suggested that E. bicyclis stems could be a source of functional foods and cosmetic products. [ABSTRACT FROM AUTHOR]

Pelvetia canaliculata (L.) Dcne. et Thur. is a marine brown macroalga within the Fucaceae (Fucales, Phaeophyceae, Ochrophyta) and the only species remaining in the monotypic genus Pelvetia. Abundant on sheltered rocky shores of the North-East Atlantic, Pelvetia forms a distinct horizontal band along the upper fringe in the intertidal, between maritime lichens and Fucus spp. Pelvetia canaliculata is a perennial species, characterized by dichotomously branching thalli 10–15 cm in length, forming narrow channels ("channelled wrack"). Distributed on the extreme upper shore, the species is exposed to atmospheric conditions for prolonged periods between spring high tides; photosynthesis recovers quickly, and fully, after water loss. Effective de-epoxidation of the xanthophyll cycle observed in P. canaliculata constitutes an important photoprotective mechanism in this species which receives high doses of solar radiation during tidal emersion. In comparison with other intertidal brown macroalgae, only few studies have investigated its chemical composition. Pelvetia typically presents high levels of sulphated polysaccharides, alginic acid, and polyphenols, associated with antioxidant and other biological activities. It accumulates high levels of mannitol and volemitol, two sugar alcohols considered to be involved in its tolerance to extended emersion. As a natural cation exchanger, Pelvetia biomass displays high biosorption capacities for toxic metals. Besides its slow growth rate and related small quantities of biomass, low protein content coupled with low degradability, have so far limited its potential for valorization. [ABSTRACT FROM AUTHOR]

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales. [ABSTRACT FROM AUTHOR]

Food production is facing challenging times due to the pandemic, and climate change. With production expected to double by 2050, there is a need for a new paradigm in sustainable animal feed supply. Seaweeds offer a highly valuable opportunity in this regard. Seaweeds are classified into three categories: brown (Phaeophyceae), red (Rhodophyceae), and green (Chlorophyceae). While they have traditionally been used in aquafeed, their demand in the feed market is growing, parallelly increasing according to the food demand. Additionally, seaweeds are being promoted for their nutritional benefits, which contribute to the health, growth, and performance of animals intended for human consumption. Moreover, seaweeds contain biologically active compounds such as polyunsaturated fatty acids, antioxidants (polyphenols), and pigments (chlorophylls and carotenoids), which possess beneficial properties, including antibacterial, antifungal, antiviral, antioxidant, and anti-inflammatory effects and act as prebiotics. This review offers a new perspective on the valorization of macroalgae biomass due to their nutritional profile and bioactive components, which have the potential to play a crucial role in animal growth and making possible new sources of healthy food ingredients.

In the evolution of eukaryotes, the transition from unicellular to simple multicellular organisms has happened multiple times. For the development of complex multicellularity, characterized by sophisticated body plans and division of labor between specialized cells, symplasmic intercellular communication is supposed to be indispensable. We review the diversity of symplasmic connectivity among the eukaryotes and distinguish between distinct types of non-plasmodesmatal connections, plasmodesmata-like structures, and ‘canonical’ plasmodesmata on the basis of developmental, structural, and functional criteria. Focusing on the occurrence of plasmodesmata (-like) structures in extant taxa of fungi, brown algae (Phaeophyceae), green algae (Chlorophyta), and streptophyte algae, we present a detailed critical update on the available literature which is adapted to the present classification of these taxa and may serve as a tool for future work. From the data, we conclude that, actually, development of complex multicellularity correlates with symplasmic connectivity in many algal taxa, but there might be alternative routes. Furthermore, we deduce a four-step process towards the evolution of canonical plasmodesmata and demonstrate similarity of plasmodesmata in streptophyte algae and land plants with respect to the occurrence of an ER component. Finally, we discuss the urgent need for functional investigations and molecular work on cell connections in algal organisms.

Oxidative stress is strongly involved in the pathogenesis of neurodegenerative diseases, like Parkinson´s disease (PD). Particularly, an excess of reactive oxygen species (ROS) released by the cells promotes an oxidative stress condition, which is a main cause of tissue injury leading to nervous system dysfunction. In this work, the antioxidant, neuroprotective and anti-inflammatory activities of different fractions from the brown seaweed Bifurcaria bifurcata are presented and related with their chemical profile. The antioxidant capacity was evaluated by the Folin-Ciocalteu method, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Neuroprotective capacity was evaluated to prevent neurological cell death mediated by the neurotoxin 6-hydroxydopamine (6-OHDA) on SH-SY5Y cells, and their anti-inflammatory effects on RAW 264.7 macrophages. The ethyl acetate fractions (100 µg mL−1) exhibited significant antioxidant and neuroprotective activities in the in vitro models assayed. Furthermore, two of the most polar fractions obtained with methanol and water also evidenced a significant neuroprotective potential. Bifurcaria bifurcata fractions treatment decreased ROS production, mitochondrial dysfunction, and Caspase-3 activity. Regarding the anti-inflammatory potential, five fractions (100 µg mL−1) inhibited nitric oxide (NO) production and reduced the interleukin – 6 (IL-6) and tumor necrosis factor (TNF-α) levels. Mannitol, identified as the major component of the most bioactive fraction, protected SH-SY5Y cells against the 6-OHDA neurotoxicity mediating ROS generation mitigation, mitochondrial dysfunction, and DNA damage, together with the Caspase-3 activity inhibition. Results suggest that B. bifurcata is a relevant source of neuroprotective agents, with particular interest for preventive therapeutics. [ABSTRACT FROM AUTHOR]

Nanoplastics (NPs), plastic particles ranging from 1 to 100 nm are ubiquitous environmental pollutants infiltrating ecosystems. Their small size and widespread use in various products raise concerns for human health, particularly their association with cardiovascular diseases (CVD). NPs can enter the human body through multiple routes, causing oxidative stress, and leading to the senescence and dysfunction of endothelial cells (ECs). Although there are potential natural compounds for treating CVD, there is limited research on preventing CVD induced by NPs. This study investigates the efficacy of Ecklonia cava extract (ECE) in preventing NPs-induced premature vascular senescence and dysfunction. Exposure of porcine coronary arteries (PCAs) and porcine coronary ECs to NPs, either alone or in combination with ECE, demonstrated that ECE mitigates senescence-associated β-galactosidase (SA-β-gal) activity induced by NPs, thus preventing premature endothelial senescence. ECE also improved NPs-induced vascular dysfunction. The identified active ingredient in Ecklonia cava, 2,7'-Phloroglucinol-6,6'-bieckol (PHB), a phlorotannin, proved to be pivotal in these protective effects. PHB treatment ameliorated SA-β-gal activity, reduced oxidative stress, restored cell proliferation, and decreased the expression of cell cycle regulatory proteins such as p53, p21, p16, and angiotensin type 1 receptor (AT1), well known triggers for EC senescence. Moreover, PHB also improved NPs-induced vascular dysfunction by upregulating endothelial nitric oxide synthase (eNOS) expression and restoring endothelium-dependent vasorelaxation. In conclusion, Ecklonia cava and its active ingredient, PHB, exhibit potential as therapeutic agents against NPs-induced premature EC senescence and dysfunction, indicating a protective effect against environmental pollutants-induced CVDs associated with vascular dysfunction., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Sargassum species play a key role in habitat formation in tropical and subtropical regions; however, species identification has been hampered by the phenological plasticity exhibited in response to environmental conditions and life history. Molecular phylogenetics has challenged taxa circumscriptions and proven critical in delimiting species in this genus. Yet, the Atlantic species of Sargassum remain poorly understood, and recent studies have shown low molecular diversity between the species in the NW Atlantic. Here, we expand the taxon sampling to the NE Atlantic to assess the diversity of Sargassum in the Atlantic basin, based on a comprehensive morphological and multigene approach. We selected genes commonly used in delineating species in this genus (ITS2, rbcLS, cox3, mtsp) and explored additional markers (cox2, nad6, psbC, clpC, atpB) to infer the phylogenetic relationships between the morphospecies observed in the NE Atlantic. Phylogenetic analyses using single-gene and multigene alignments including 185 new sequences confirmed the low molecular diversity and supported the distinction of a single clade in Sargassum section Sargassum of N Atlantic benthic species. In contrast, morphological analysis resulted in the identification of 10 species and three new morphospecies that we described here but opt not to equate to species until further molecular evidence is available. Our results were congruent with previous findings from the NW Atlantic and highlight the morphological and ecological diversity of Sargassum in the Atlantic. These results suggest a recent colonization and incipient speciation of Sargassum in the Atlantic basin and showcase the need of further high-throughput analyses., (© 2024 The Author(s). Journal of Phycology published by Wiley Periodicals LLC on behalf of Phycological Society of America.)

In recent decades, the invasive seaweed Rugulopteryx okamurae has had a huge environmental impact on marine biodiversity, fisheries, GHG emissions and public health along much of the Iberian Peninsula and islands coastline. Due to the enormous amount of algae biomass that is expelled to the beaches where it slowly rots, some circular economy business initiatives, such as composting, are emerging. In the present study, we compared the quality of compost obtained from earthworms (Dendrobaena veneta), cockroaches (Eublaberus sp.), mealworms (Tenebrio molitor) and black soldier fly larvae (Hermetia illucens). Batches fed with 100% organic kitchen waste (control group) were compared with batches fed with 50% algae and 50% kitchen waste (treatment group). Our results show that the most sensitive species (D. veneta and T. molitor) to R. okamurae toxins compost adequately. The C/N ratio, electrical conductivity (EC), pH, total organic matter (TOM), C, K, K2O, Mg, MgO, N, P, P2O5, B, Cu, Ni and Zn of the compost obtained were determined. A high quality compost was obtained in which only the EC values are slightly elevated. Particularly good was the compost obtained with H. illucens and Eublaberus sp. This quality is in agreement with previous research on the mass balance of composting. Therefore, both species offer, in the field of circular economy, encouraging prospects for the development of composting enterprises., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. In fact, the technological solutions implemented here have been produced exclusively under research guidelines. The authors do not have any shareholding in any composting company, nor do they charge any subsidies for the removal of the invasive algae. There are also no political or ideological interests that could affect the research., (Copyright: © 2024 Patón, García-Gómez. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Brown algae are multicellular photosynthetic organisms that have evolved independently of plants and other algae. Here, we have studied the determinism of body axis formation in the kelp Saccharina latissima. After microdissection of the embryo, we show that the stalk, an empty cell that retains the embryo on the maternal tissue, represses longitudinal cell divisions in the early embryo, thereby reinforcing the establishment of the initial apico-basal axis. In addition, it promotes cell growth and controls cell shape and arrangement in the flat oblong embryo composed of cells aligned in rows and columns. Although the stalk persists for several weeks until the embryo reaches at least 500 cells, proper embryogenesis requires connection to maternal tissue only during the first 4 days after fertilisation, i.e. before the embryo reaches the 8-cell stage. Transplantation experiments indicate that the maternal signal is not diffused in seawater, but requires contact between the embryo and the maternal tissue. This first global quantitative study of brown algal embryogenesis highlights the role of MUM, an unknown maternal message, in the control of growth axes and tissue patterning in kelp embryos., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

Macroalgae have long served as bioindicators of pollution in coastal marine environments. However, conventional pollution assessment methods often take a compartmentalized approach, either focusing on macrophyte biological parameters or independently analyzing heavy metal and oil product bioaccumulation within them. This study establishes connections between: (1) the characteristics of chemical pollution in brown, green, and red macroalgae, (2) organic pollution in the nutrient medium, and (3) the resulting changes in phytocenosis composition and macrophyte morphological characteristics. The research was conducted in the coastal zone near the Sochi River mouth on the Black Sea coast of Russia, encompassing the urban center of the Sochi metropolitan area. Inductively Coupled Plasma (ICP) analysis quantified the accumulation levels of 60 chemical elements within macrophyte algae. The novel aspect of this study is the development of a quantitative metric for assessing the overall chemical pollution impacting the ecologically crucial macroalgae Cystoseira. This systematic approach represents a significant advancement in the comprehensive evaluation and management of coastal water quality. The study identified two contrasting accumulation patterns: (1) pollution-tolerant annual algae exhibited an exclusion mechanism for chemical elements, while (2) Cystoseira displayed a non-exclusion accumulation pattern, potentially explaining its absence in the most heavily polluted zone. This approach paves the way for establishing a standardized scale for algal chemical pollution, reflecting a range from permissible to highly hazardous levels in seawater. This will enable rapid acquisition of both qualitative and quantitative pollution data, streamline monitoring efforts, and expedite the implementation of control measures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study explores the reasons behind the variations in the enantioselectivity of the sulfoxidation of methyl phenyl sulfide by marine-derived vanadium-dependent haloperoxidases (VHPOs). Twelve new VHPOs of marine organisms were overexpressed, purified, and tested for their ability to oxidize sulfide. Most of these marine enzymes exhibited nonenantioselective behavior, underscoring the uniqueness of An VBPO from the brown seaweed Ascophyllum nodosum and Cp VBPO from the red seaweed Corallina pilulifera , which produce ( R )- and ( S )-sulfoxides, respectively. The enantioselective sulfoxidation pathway is likely due to direct oxygen transfer within the VHPO active site. This was demonstrated through molecular docking and molecular dynamics simulations, which revealed differences in the positioning of sulfide within An VBPO and Cp VBPO, thus explaining their distinct enantioselectivities. Nonenantioselective VHPOs probably follow a different oxidation pathway, initiating with sulfide oxidation to form a positively charged radical. Further insights were gained from studying the catalytic effect of VO 4 3- on H 2 O 2 -driven sulfoxidation. This research improves the understanding of VHPO-mediated sulfoxidation and aids in developing biocatalysts for sulfoxide synthesis.

The biosynthesis of silver nanoparticles, both economically and environmentally advantageous, uses algae extracts. In the current work, we extracted the marine brown alga Hormophysa triquetra (C. Agardh) kützing and used it to make silver nanoparticles (HAgNPs) which are characterized via UV-visible spectrophotometers, Transmission Electron Microscopy (TEM), Zeta potential, and FTIR then used them in the bio adsorption of crude petroleum oil from seawater, comparing them with H. triquetra aqueous extract. UV scan of the phycosynthesized silver nanoparticles achieved the highest absorption at 369 nm. TEM showed that the synthesized HAgNPs occur with smooth, spherical, and semispherical forms with sizes ranging from 12.04 to 20.67 nm, zeta potential illustrated that HAgNPs were charged with -22.1, The H. triquetra aqueous extract's FTIR examination identified several active groups like - OH, -C=C-, NO, -CH, CCl, -C ≡ C-H: CH which are responsible for the bioadsorption of crude petroleum oil. When extracting crude petroleum oil from seawater, HAgNPs worked better than its aqueous extract. The maximum removal % for light n-alkanes (Ln-alk), heavy n-alkanes (Hn-alk), and PAHs were 70.4 %, 71.63 %, and 75.38 % respectively for H. triquetra aqueous extract with adsorption capacity 889, 511, 273 μg/g at salinity 36 % and pH 5, while in case of HAgNPs the results were 75.81 %, 77.15 %, and 80.56 %, respectively with adsorption capacity 957, 550, 292 μg/g at the same salinity and pH., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The reuse of biomass waste has been gaining attention in adsorption processes to remove pollutants of emerging concern from water and wastewater. In this work, the potential of alginate-extracted macro-algae waste to uptake synthetic dyes and metal cations was evaluated in comparison with raw algae. In affinity assays, both materials were able to remove metal cations and cationic dyes up to maximum rates, and no significant removal was observed for an anionic dye in an acidic medium. Competition was observed in multi-component systems of metal cations and dyes. For binary samples containing organic and inorganic contaminants, kinetic modeling evidenced the distinct nature of both types of adsorbates. Pb(II) biosorption was best described as a first-order process, while second-order and Elovich models better fitted methyl blue (MB) uptake data. For equimolar binary samples, the Sips isothermal model fitted the experimental data more satisfactorily at room temperature. Isotherms for 20, 30, 40, and 60 °C exhibited favorable adsorption profiles with spontaneous ΔG values for both raw macro-algae and waste from alginate extraction. Maximum adsorption capacities were competitive with previous reports in the literature for a wide range of biomaterials, pointing to the slightly higher efficiency with algae waste in batch experiments. In elution tests, HNO 3 (0.5 M) showed the best recovery rates of metal cations. Continuous biosorption operation revealed the performance of the brown algae waste was considerably more efficient than raw algae with breakthrough biosorption capacities up to 3.96 and 0.97 mmol.g -1 for the removal of Pb(II) and MB, respectively. A total of 3.0 g of algae and algae waste were able to deliver 1.20 and 1.62 L of contaminant-free water, respectively. XPS analyses corroborate previous assays that pointed to the prevalence of physisorption with evidence of complexation, ionic exchange, and hydrogen displacement mechanisms., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The COVID-19 disease is a major problem affecting human health all over the world. Consequently, researchers have been trying to find solutions to treat this pandemic-scale disease. Even if there are vaccines and approved drugs that could decrease the spread of this pandemic, multidisciplinary approaches are still needed to identify new small molecules as alternatives to combat COVID-19, especially those from nature. In this study, we employed computational approaches by screening 17 natural compounds from the tropical brown seaweed Sargassum polycystum known to have anti-viral properties that benefit human health. This study assessed some seaweed natural products that are bound to the PLpro of SARS-CoV-2. By employing pharmacophore and molecular docking, these natural compounds from S. polycystum showed remarkable scores for protein targets with competitive scores compared to X-ray crystallography ligands and well-known antiviral compounds. This study provides insightful information for advanced study and further in vitro examination and clinical investigation for drug development prospects of abundant yet underexploited tropical seaweeds.

The present study develops a formulation of face cream which is made by the ethanol extract of Sargassum spp. (Phaeophyceae) from the Jordanian Gulf of Aqaba. A different type of formulations (from F1 to F8), such as oil in water were discovered to obtain the best formula of a cosmetic cream of marine herbal origin. The evaluation of all formulations (F1 to F6) has been done by the analysis of different parameters like viscosity, spread ability and stability. An ethanol fraction analyzed from a sample of Sargassum spp. showed that F2, F3, F6 and F7 were of the best homogeneity. These formulas were the subject of further evaluation tests. By implementing the dye test to formulas F2, F3, F6 and F7, all were showed a O/W feature of emulsion. The evaluation of formulations of F3, F4, F6 and F7 was conducted by using an accelerated test. Parameters including homogeneity, appearance, type of smear and removal were tested and showed acceptable stability. Among the eight formulations (F1-F8), only F2 and F6 showed the best results in terms of stability, texture and evaluation test. F2 and F6 are held intact with good appearance and consistency that continues until day 15 after preparation. Hence, the study suggests that the composition of extract and the base of the cream F2 and F6 are more stable and safer. [ABSTRACT FROM AUTHOR]

Phlorotannins are polyphenolic compounds in brown algae and can be used as a natural UV filter in sunscreen formulations. The aim of the present study was to characterize the biological activities of phlorotannins-rich fractions from the brown alga Polycladia myrica and to validate the protective effect as well as stability of cream formulation with phlorotannins against UVR. With respect to antioxidant properties, the ethyl acetate fraction (EF) possessed the highest DPPH radical scavenging (65 ± 0.2%), and the highest antioxidant activity (11.2 ± 0.2 μg ASA mg−1). The EF was active against Gram-positive bacteria with EF effectively reducing UVB-induced cytotoxicity in HaCaT keratinocytes. The cream formulation with 5% EF revealed a high sun protective factor (31.79 ± 4.73), UVA/PF (24.67 ± 4.03), critical wavelength (383.2 ± 0.1 nm), and UVA/UVB ratio (0.98 ± 0.01). The cream formulation was completely homogeneous and had a pH close to human skin pH. The cream was stable in the cooling-heating cycle and the DPPH scavenging activity of the cream was not altered for 30 days of storage at temperatures of 4–40 °C. These findings are promising for the use of brown alga P. myrica extract as a valuable source of sunscreen protective substance for pharmaceutical and cosmetic applications. [ABSTRACT FROM AUTHOR]

The brown algae are an important but understudied group of multicellular marine organisms. A number of genetic and genomic tools have been developed for the model brown alga Ectocarpus; this includes, most recently, chromatin immunoprecipitation methodology, which allows genome-wide detection and analysis of histone post-translational modifications. Post-translational modifications of histone molecules have been shown to play an important role in gene regulation in organisms from other major eukaryotic lineages, and this methodology will therefore be a very useful tool to investigate genome function in the brown algae. This article provides a detailed, step-by-step description of the Ectocarpus ChIP protocol, which effectively addresses the difficult problem of efficiently extracting chromatin from cells protected by a highly resistant cell wall. The protocol described here will be an essential tool for the future application of chromatin analysis methodologies in brown algal research. [ABSTRACT FROM AUTHOR]

The use of brown-macroalgae (Phaeophyceae) as an alginate source is very broad, covering the food and non-food industry, because of that it is necessary to know the safety of these natural resources, one of which is safe from heavy metal contamination. The purpose of this study was to determine heavy metals concentrations accumulated in several types of Phaeophyceae (brown macroalgae) as an alginate source from Malang Rapat waters, Bintan. The method used was descriptive non-experimental. The determination of the location of sampling was done by purposive sampling method. Samples were taken through free collection, identified species and measured of metal contamination concentrations for As, Cd, and Pb. The data obtained were analyzed descriptively. The results showed that Phaeophyceae found in Malang Rapat waters were Turbinaria conoides, Sargassum aquifolium, Padina australis, Hormophysa cuneiformis with each metal concentration contamination of As 13.95 to 23.30 µg.g-1 dry weight; Cd from 0.33 to 1.08 µg.g-1 dry weight and Pb from 4.72 to 9.92 µg.g-1 dry weight. This study showed that all metal contamination ranges in all Phaeophyceae were on the verge of the maximum limit set by the National Standardization Agency of Indonesia Indonesian (SNI) No 7387 of 2009 and National Agency of Drug and Food Control of RI (BPOM) Regulation No 5 of 2018 for dried macroalgae product so that Phaeophyceae from Malang Rapat waters - Bintan was not safe to be used as raw material for alginate source or other processed products of brown-macroalgae.

The phylogeny of brown algae (Phaeophyceae) has undergone extensive changes in the recent past due to regular new scientific insights. We used nuclear 18S rDNA with an extensive dataset, aiming to increase the accuracy and robustness of the reconstructed phylogenetic trees using a simultaneous sequence-structure approach. Individual secondary structures were generated for all 18S rDNA sequences. The sequence-structure information was encoded and used for an automated simultaneous sequence-structure alignment. Neighbor-joining and profile neighbor-joining trees were calculated based on 186 phaeophycean sequence-structure pairs. Additionally, sequence-structure neighbor-joining, maximum parsimony and maximum likelihood trees were reconstructed on a representative subset. Using a similar approach, ITS2 rDNA sequence-structure information was used to reconstruct a neighbor-joining tree including 604 sequence-structure pairs of the Laminariales. Our study results are in significant agreement with previous single marker 18S and ITS2 rDNA analyses. Moreover, the 18S results are in wide agreement with recent multi-marker analyses. The bootstrap support was significantly higher for our sequence-structure analysis in comparison to sequence-only analyses in this study and the available literature. This study supports the simultaneous inclusion of sequence-structure data at least for 18S to obtain more accurate and robust phylogenetic trees compared to sequence-only analyses. [ABSTRACT FROM AUTHOR]

Ecklonia cava is an edible kelp species distributed in Korea and Japan with diverse uses in ecological restoration, traditional medicine, and the pharmaceutical and abalone industries. These features make E. cava a good candidate for cellular biotechnology research, which is often dependent on protoplasts. To date, however, there have been no studies that have focused on the isolation of protoplast from E. cava. In this study, we sought to optimize the yield of protoplasts from cultured young sporophytes of E. cava using commercial enzymes, with a particular focus on identifying the key conditions for achieving high protoplast yield, including enzyme concentration, chelation pre-treatment, growth, temperature, incubation time, pH, and osmolarity. Protoplast production conditions were modeled using response surface methodology (RSM) via Box–Behnken design (BBD), and the practical utility of these conditions was experimentally verified. We found that an enzyme composition of 1.67 % cellulase RS and 4 U mL−1 alginate lyase without chelation pre-treatment, at 1570 mOsm L−1 H 2 O and pH 6 produced the highest protoplast yield of 4.45 ± 2.16 × 107 protoplasts g−1 fresh weight when incubated at 20 °C for 4 h using young (2-week-old) cultures. Our data revealed a strong positive correlation between growth rate and protoplast yield, thereby indicating that growth rate could serve as an index for determining the optimal timing of protoplast isolation from cultured material. The optimized protocol resulted in protoplasts capable of cell wall formation, division, and regeneration. These findings indicate the efficacy of commercial enzymes in protoplast isolation and that BBD-mediated RSM is a useful approach for the production of viable protoplasts from kelp sporophytes. • Single-step production of protoplasts from economically important brown alga Ecklonia cava using commercial enzymes • Identifying the key conditions for achieving high protoplast yield, including enzyme concentration, chelation pre-treatment, growth, temperature, incubation time, pH, and osmolarity • Protoplast production conditions were modeled using response surface methodology (RSM) via Box–Behnken design (BBD) • The conditions for highest protoplast yield were 1.67% cellulase RS and 4 U mL-1 alginate lyase without chelation pre-treatment, 1570 mOsm L-1 H 2 O, and pH 6 • BBD-mediated RSM is a useful approach for the production of protoplasts from kelp sporophytes [ABSTRACT FROM AUTHOR]

Seaweeds contain a wide range of secondary metabolites which serve multiple functions, including chemical and ecological mediation with microorganisms. Moreover, owing to their diverse bioactivity, including their antibiotic properties, they show potential for human use. Nonetheless, the chemical ecology of seaweeds is not equally understood across different regions; for example, Antarctic seaweeds are among the lesser studied groups. With the aim of improving our current understanding of the chemical ecology and potential bioactivity of Antarctic seaweeds, we performed a screening of antibiotic activity using crude extracts from 22 Antarctic macroalgae species. Extractions were performed separating lipophilic and hydrophilic fractions at natural concentrations. Antimicrobial activity assays were performed using the disk diffusion method against seven Antarctic bacteria and seven human pathogenic surrogates. Our results showed that red seaweeds (especially Delisea pulchra) inhibited a larger number of microorganisms compared with brown seaweeds, and that lipophilic fractions were more active than hydrophilic ones. Both types of bacteria tested (Gram negative and Gram positive) were inhibited, especially by butanolic fractions, suggesting a trend of non-specific chemical defence. However, Gram-negative bacteria and one pathogenic fungus showed greater resistance. Our study contributes to the evidence of antimicrobial chemical interactions between Antarctic seaweeds and sympatric microorganisms, as well as the potential of seaweed extracts for pharmacological applications. [ABSTRACT FROM AUTHOR]

Alginate is an attractive marine resource-based biopolymer, which has been widely used in pharmaceutical, food and textile industries. This paper reviewed the latest development of the conventional and alternative processes for alginate extraction from brown seaweed. To improve extraction yield and product quality, various studies have been carried out to optimize the operation condition. Based on literature survey, the most commonly used protocol is soaking milled seaweed in 2% (w/v) formaldehyde, overnight, solid loading ratio of 1:10–20 (dry weight biomass to solution), then collecting the solid for acid pre-treatment with HCl 0.2–2% (w/v), 40–60 °C, 1:10–30 ratio for 2–4 h. Next, the solid residue from the acid pre-treatment is extracted using Na2CO3 at 2–4% (w/v), 40–60 °C, 2–3 h, 1:10–30 ratio. Then the liquid portion is precipitated by ethanol (95%+) with a ratio of 1:1 (v/v). Finally, the solid output is dried in oven at 50–60 °C. Novel extraction methods using ultrasound, microwave, enzymes and extrusion improved the extraction yield and alginate properties, but the financial benefits have not been fully justified yet. To improve the sustainable production of alginate, it is required to promote seaweed cultivation, reduce water footprint, decrease organic solvent usage and co-produce alginate with other value-added products. [ABSTRACT FROM AUTHOR]

There is a growing demand for bioactive compounds derived from green extraction methods from the food and cosmetic industries. Pulsed electric field (PEF)-assisted extraction has been applied for numerous foods but few on macroalgae. The present study examines PEF as part of the extraction process of polyphenols and carbohydrates from the brown macroalga Alaria esculenta. The effect of PEF treatment (0, 720 pulses) and ethanol concentration (0%, 15%) on the extraction of bioactive compounds from Alaria esculenta was assessed. To determine the pigment yield a second extraction was conducted with 60% ethanol or fractionated coconut oil with or without lecithin. The PEF treated aqueous extract had the highest yield for phenolic (10.4 ± 3.7 mg GAE g−1 DW) and carbohydrate content (21.4 ± 1.8 mg GE g−1 DW) as well as ferric reducing activity power and DPPH radical scavenging activity. The 60% ethanol extracts had a higher fucoxanthin content (73 ± 14 mg (100 g)−1 FD pulp) than the oil (2.1 mg (100 g)−1 FD pulp) and oil with lecithin (17 mg (100 g)−1 FD pulp) extracts. We obtained crude aqueous and low ethanolic extracts containing bioactive that show antioxidant activities, with either low temperature or PEF treatment from dried blades of Alaria esculenta. PEF treatment did not influence the pigment extraction with oil or 60% ethanol. [ABSTRACT FROM AUTHOR]

Global demand for seaweed is increasing, resulting in the rapid growth of the seaweed industry. To sustain and enhance the industry (seaweed growers and processors), it is essential to establish and optimize post-harvest food processing practices to extend the shelf life of the fresh, edible product. Blanching and freezing were applied in this study to offer longer-term storage to enable the distribution of sugar kelp (Saccharina latissima), farm-raised in Maine, USA. The objectives were to evaluate blanching, specifically the impacts of blanching method (direct immersion or vacuum packaged), temperature (80 or 100 °C) and time (5 or 30 s), kelp form (whole blade or shredded), and the effects of frozen storage on food product qualities including color, texture, drip loss, mineral content, total phenolic content, and the native microflora of sugar kelp after thawing. The fresh brown kelp developed a vivid green color immediately after blanching, especially with higher blanching temperature and longer blanching time. Drip loss was higher in blades than in shredded slaw, and vacuum packaged blanching produced higher moisture content, phenolic compounds, and antioxidant activity. Results substantiate the importance of the blanching method, temperature, and time on frozen kelp quality. Blanching prior to freezing resulted in relatively higher product quality than unblanched frozen kelp despite some losses in hardness and color. Frozen storage had minimal to no impact on texture, aerobic plate count, and psychrotrophic microorganisms. Higher temperature, longer time, and vacuum packaged blanching is suggested to extend the marketable shelf life of sugar kelp to at least 6 months at − 20 °C. [ABSTRACT FROM AUTHOR]

Use of cultivars with certain agronomical traits has been throughout the development history of kelp Saccharina japonica farming in China. Pursuit of high yield had been on top of all the parameters. However, in recent years, demand for better blade quality has steadily become intensive, especially in the northern farming region of this country. In this article, we report a newly bred, intraspecific hybrid E25 (as designation code), of its biological features and its applicability as a potential cultivar in the related farming region. A fully grown sporophyte of E25 could reach 4–5 m in length, 0.6–0.8 m in width, and 3–5 kg in fresh biomass depending on the farming zones and growing density within ca. 7-month cultivation period from November to May–June of next year. Unlike most of the cultivars or naturally grown sporophytes, sporophyte of E25 lacks fascia in the middle of the strip and possesses smooth blades. It has thicker ruffled undulate margins on both longitudinal sides and relatively low water content in its blade. Due to its much higher chlorophyll a content, blanched product is greener than most of the other cultivars, much favored by the processing industry. Seedling production of E25 relays on a pair of vegetatively propagated unialgal male and female gametophytes. High polymorphic microsatellite markers could accurately identify its uniformed genotype and distinguish it from other conventional cultivars. The first filial sporophytic generation of E25 (E25-F1) maintains the same yield level as its parent, reaching 23–25 kg m−1 cultivation rope, but with larger deviations in individual sizes as reflected by its higher coefficient of variations (CV). [ABSTRACT FROM AUTHOR]

Sargassum thunbergii is a brown macroalga endemic to the northwest Pacific. It plays important ecological roles in the structure and maintenance of coastal marine ecosystems. The bioactive compounds extracted from S. thunbergii have been extensively documented for potential use in anti-obesity, anti-inflammatory activity, anti-tumor, anti-oxidant and aquacultural drugs. The species is edible and contains relatively high levels of proteins, minerals and several types of amino acids. The present work compiles recently published literature on S. thunbergii, with particular focus on cultivation efforts in China, including the breeding of seedlings and cultivation at sea. A concise review of possible applications is given. Distribution, range shifts associated with past climate change, population genetic structure and connectivity, life history, reproduction and development are all detailed. The review provides important guidelines for future large-scale farming of S. thunbergii. This will help aquaculturalists (phyconomists) to meet the expected increases in demand by industrial users. It will also help to conserve natural populations which may be declining due to destructive harvesting and rapid ocean changes. [ABSTRACT FROM AUTHOR]

The review covers the history of the discovery and nomenclature of fucoidans — an interesting group of fucose-containing sulfated polysaccharides extracted from brown algae (Phaeophyceae) with a wide range of promising biological activities. The factors affecting complex molecular structure of these heterogeneous biopolymers are characterized; the authors give an overview of a series of original articles clarifying the role of the bioglycan molecular structure elements (chemical groups, molecular weight, glycosidic linkages, monosaccharides) on some biological properties — anticoagulant, anti-inflammatory, antioxidant, etc. Despite a long history of studying fucoidans, unraveling the role of certain fucoidans' structural features is far from being complete because of the molecular complexity caused by both endogeneous and environmental factors, as well as by reproducibility issues of extraction processes. The sources of scientific literature were found in various electronic databases (PubMed, Web of Science, Science Direct) and library search.

This updated list is composed of a total of 661 records, which includes 71 brown algae, 450 red algae, 137 green algae, and three seagrasses, with an overall rate of endemism of 13.2%. Almost half (46.7%) of the Hawaiian records presented here are represented by at least one DNA sequence, while 16.3% are confirmed through a DNA sequence match to a topotype, and 6.7% are confirmed through a DNA sequence match to a type specimen. The data are presented in the context of the natural history of the Hawaiian Islands, which is heavily influenced by the volcanic hotspot origin of the archipelago in the middle of the Pacific Ocean, as well as the important cultural role of seaweeds and other marine plants in Hawai‘i, and the current threats to marine ecosystems, which include the introduction and proliferation of a number of invasive marine macroalgae.

Although many studies predict extensive future biodiversity loss and redistribution in the terrestrial realm, future changes in marine biodiversity remain relatively unexplored. In this work, we model global shifts in one of the most important marine functional groups-ecosystem-structuring macrophytes-and predict substantial end-of-century change. By modelling the future distribution of 207 brown macroalgae and seagrass species at high temporal and spatial resolution under different climate-change projections, we estimate that by 2100, local macrophyte diversity will decline by 3-4% on average, with 17 to 22% of localities losing at least 10% of their macrophyte species. The current range of macrophytes will be eroded by 5-6%, and highly suitable macrophyte habitat will be substantially reduced globally (78-96%). Global macrophyte habitat will shift among marine regions, with a high potential for expansion in polar regions., (© 2024. The Author(s).)

The Genus Turbinaria is still chemically and pharmacologically underexplored. These brown algae belong to the family Sargassaceae. Therapeutic potentials of pure compounds isolated from the Genus Turbinaria are extraordinarily promising as antiproliferative, antipyretic, anti-inflammatory immunostimulatory, anti-diabetic, anti-obesity, antiviral, antimicrobial, cardioprotective, hepatoprotective and hypolipidemic. Those activities are represented by diverse classes of compounds including sterols, amino acids, fatty acids, alcohols, halocarbons, hydrocarbons, carbohydrates, esters and cyclic tetrapyrrole compounds. This review focuses on the Genus Turbinaria during the period 1972 to 2019. [ABSTRACT FROM AUTHOR]

Defining species in the brown algal genus Colpomenia is a challenging endeavour because of their morphological similarity, overlapping phenotypic variation, the absence of conspicuous diagnostic characters, and often lack of reproductive structures crucial for their identification. Thus, the use of molecular tools has become widely used to study Colpomenia taxonomy and evolution. The following four Colpomenia species are described along the Australian coast: C. claytoniae M.Boo, K.M.Lee, G.Y.Cho & W.Nelson, C. ecuticulata M.J.Parsons, C. peregrina Sauvageau, and C. sinuosa (Mertens ex Roth) Derbès & Solier. The objective of this study was to assess the diversity of Colpomenia species in southern and south-eastern Australia by using DNA barcoding techniques and single-marker species delimitation methods. We generated 44 new COI-5P DNA sequences from nine different populations across three Australian states (South Australia, Victoria and Tasmania), and applied 13 variations of four species delimitation methods (ABDG, SPN, PTP, GMYC). Our results recognised three Colpomenia species in the region, namely, C. sinuosa , C. claytoniae , and C. peregrina. Colpomenia sinuosa is the most widely distributed species in Australia. Colpomenia peregrina and C. claytoniae presented high levels of intraspecific genetic divergence. We did not find C. ecuticulata , although it has been previously reported from nearby our sampling area. Many macroalgal species are difficult to identify to the species level because of their morphological simplicity, phenotypic variation and frequent homoplasies. DNA barcode is a molecular technique that helps identify morphologically challenging specimens. We applied DNA barcoding techniques and species delimitation methods to study species diversity of the common intertidal brown algal genus Colpomenia in south-south-eastern Australia. We confirm the presence of three Colpomenia species in southern–south-eastern Australia, although there are four species described for this region. Future research including more widespread sampling is required to assess further Colpomenia species diversity across the entire country. [ABSTRACT FROM AUTHOR]

Previous studies have documented 836 species of marine macroalgae from Viet Nam. In the present study, marine algal samples were collected along the coast of south central Viet Nam. Morphological observations revealed three new records for the South China Sea, including Zellera tawallina and Grateloupia huangiae (Rhodophyta), and Dictyota grossedentata (Phaeophyceae). The results of morphological observations were supported by phylogenetic analyses. Therefore, the seaweed flora of Viet Nam now comprises 838 marine macroalgal species including 418 Rhodophyta, 149 Phaeophyceae, 183 Chlorophyta, and 88 Cyanobacteria. [ABSTRACT FROM AUTHOR]

Aqueous extracts from Ascophyllum nodosum brown edible seaweeds were obtained after continuous ultrasound-assisted extraction. The effect of sonication time (from 2 to 6 min), sonication amplitude (from 80 to 100%) and solvent-solid ratio (from 20 to 40 g water g−1 dried seaweed) on the extracts features was studied employing a Box-Behnken experimental design. Extracts were characterised by polyphenols, carbohydrate and uronic acid content. Response surface method (by means of a quadratic model) was successfully employed to relate chemical composition of extracts and operation conditions. Optimal experimental conditions were established to obtain maximal polyphenols content and several polyphenols-carbohydrates ratios together with the conditions that minimise energy consumption per extracted polyphenols amount relationship. Antioxidant capacities of extracts were measured employing different methods (DPPH, FRAP and ABTS). Positive linear correlations between antioxidant activity and total polyphenols content were established. [ABSTRACT FROM AUTHOR]

We investigated the effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of juvenile (JS) and mature sporophytes (MS) of a temperate edible brown alga Undaria pinnatifida cultivated in northeastern Japan, using optical dissolved oxygen sensors and pulse amplitude modulation (PAM)–chlorophyll fluorometry. Photosynthesis–PAR experiments at 8, 15, and 22 °C revealed that the maximum net photosynthesis differed with temperature. Values for compensation and saturation PAR indicated a high affinity for a low-light environment. The photosynthetic response of U. pinnatifida to temperature revealed an optimum temperature for oxygenic photosynthesis of 18 °C, which was lower than other laminarian kelps and inconsistent with the wide distribution range of this U. pinnatifida. High temperature and irradiance tolerance differed between MS and JS. Notably, Fv/Fm of MS remained above 0.5 at 28 °C after 168 h of incubation under dark conditions, whereas Fv/Fm was reduced to 0 for the juveniles. Six hours of constant exposure to 200 (low) and 1000 μmol (high) photons m−2 s−1 at 8, 15, and 22 °C induced chronic photoinhibition in all both MS and JS. In contrast to MS, the JS did not recover from photoinhibition in either of the PAR treatments, regardless of a period of darkness. The physiological performance of U. pinnatifida sporophytes indicate an affinity to low light, especially for JS. We expect that these finding will lead to further improvements in commercial production methods to prevent the withering of juvenile sporophytes. [ABSTRACT FROM AUTHOR]

In hybridization experiments, productivity improvement and modification of morphologies and chemical compositions were recently demonstrated for Macrocystis sporophytes in the Southeastern Pacific. However, the plasticity for gametogenesis environmental requirements in hybrid crosses has not been studied, even though such plasticity is a key aspect to design kelp breeding programs or to implement restoration set-ups. Effects of temperature (9–18 °C) and photon irradiance (10–120 μmol photons m−2 s−1) were estimated for reproductive success (RS) and sex ratio in an integrifolia × pyrifera inter-cultivar cross. As starting materials for breeding, we used (i) clonal gametophytes (i.e., strains from culture collection germplasms) and (ii) sporulation products (e.g., gametophytes from sporophylls), producing inter-locality crosses and their respective intra-locality controls. In germplasm-originated cultures, integrifolia (integrifolia ♀ × integrifolia ♂) and pyrifera (pyrifera ♀ × pyrifera ♂) controls and pyrifera ♀ × integrifolia ♂ crosses resulted in healthy progenies, but the reciprocal mate integrifolia ♀ × pyrifera ♂ was inviable. Overall, the viable hybrid and pyrifera crosses showed the highest reproductive success (RS) up to 14 °C and 50 μmol photons m−2 s−1. Towards higher conditions of temperature and light, the hybrid and integrifolia combinations showed better RSs. In sporophyll–originated experiments, we compared the RS in gametophytes from integrifolia and pyrifera sporophytes but also from F1 hybrids cultivated in tanks in northern Chile, under similar temperature and irradiance gradients. The lowest reproductive successes were also detected in integrifolia, although this morph demonstrated a more stable sex ratio throughout thermal gradient. In this case, the hybrid gametophytes were less prolific than in the germplasm trials, but such hybrid combination performed better than the controls at higher temperatures (16–17 °C). Once optimum irradiances and temperature from different studies along the Chilean coast are clustered together against their location, they showed an inverse correlation between optima and a latitudinal gradient for Macrocystis gametogenesis. In such scenario, our crosses cultivated in northern Chile (sporophyll-generated) showed optima towards much higher conditions especially for irradiance. The hybrid gametophytes performed similarly to integrifolia potentially as a result not only from an integrifolia genetic background but also from the cultivation conditions of their sporophyte parents in northern Chile. Implications of these results are discussed in ecological and aquaculture contexts. [ABSTRACT FROM AUTHOR]

Close to 66% of the annual national production of the brown alga Undaria pinnatifida, about 115 thousand tonnes (fresh weight), is produced through farming in Liaoning Province in north China. To clarify the agronomic characters and genetic differences of currently farmed U. pinnatifida, we investigated three major farmed cultivars in combination with other traditional ones focusing specially on sporophylls, one of the principal end products in a typical farm at Lvshun, Dalian city. Results showed that these cultivars differ in timing of maturation and are arranged to be harvested in sequence in the farm to diversify the periods of harvesting and processing. Sporophyll fresh weight and the stipe width are positively correlated with the growth of the plant. Ten neutral microsatellite markers were used to assess relationships among major farmed cultivars. Both genetic distance and Bayesian model-based analyses showed that there was genetic differentiation among C1, C2, and other traditional cultivars. C3 showed the highest genetic variations in major farmed cultivars, with three private alleles and a mean expected heterozygosity of 0.817. In general, prominent genetic divergences were found among different cultivars confirming the effect of consecutive selection, while weak relationships were observed between sporophyll forms and genotypes. [ABSTRACT FROM AUTHOR]

Beach-cast marine algae are a potential biomass for several biofunctional products and occur in large volumes in some coastal regions due to natural current processes or drifting algae like pelagic Sargassum. Antioxidant activity and chemical composition of methanolic and aqueous extracts from fifteen beach-cast marine algae from the Brazilian Coast were evaluated. In general, the highest antioxidant activities were found in extracts from brown macroalgae followed by the extracts of red algae, and the lowest activities were detected in the green beach-cast algae. The concentrations of phenolic compounds and carbohydrates exhibited a positive correlation with the antioxidant activities of the tested extracts. To the best of our knowledge, this is one of the few worldwide studies concerning beach-cast seaweeds and antioxidant activity and related antioxidant metabolites. This study suggests that these algae are potential sources for obtaining extracts with antioxidant properties, rich in phenolic compounds and sulfated carbohydrates. Beach-cast macroalgae are unused biomass and the beneficial utilization of this biomass for prospection of natural products and functional foods is suggested. [ABSTRACT FROM AUTHOR]

The heterokont benthic multicellular algae Schizocladia ischiensis E.C. Henry, K. Okuda et H. Kawai (Schizocladiophyceae), Hecatonema terminale (Kützing) Kylin and Striaria attenuata (Greville) Greville (Phaeophyceae) are reported for the first time from the waters around the Maltese islands in the central Mediterranean. They were identified through algal isolation from incubated natural substrata, coupled with DNA barcoding targeting the biomarkers COI and rbcL plus the RuBisCO spacer. For three additional brown algae, Colpomenia sinuosa (Mertens ex Roth) Derbès et Solier, Asperococcus bullosus J.V.Lamouroux and Sphacelaria sp., DNA sequences confirmed previous morphology-based records from Malta. This paper also provides an updated literature-based species list of the marine macroalgae present in Malta. [ABSTRACT FROM AUTHOR]

• The genus Padina is highly diverse and is still chemically and pharmacologically underexplored. • Padina is widely distributed in many environmental conditions. • Diverse bioactivities such as hypolipidemic, hypoglycemic, antimicrobial, cytotoxic, anti-obesity, cardioprotective, hepatoprotective and immunostimulatory activities have been reported. • This review covers the literature on Genus Padina during the period 1989 to 2020. The genus Padina , commonly called sea fan ribbon weeds, belongs to the family Dictyotaceae. It is considered a sea vegetable and is of nutritional interest owing to its low-calories. Therapeutic potentials of certain compounds isolated from some Padina species have promising hypolipidemic, hypoglycemic, antimicrobial, cytotoxic, anti-obesity, cardioprotective, hepatoprotective and immunostimulatory activities. This review covers the chemistry and pharmacological potential of members of genus Padina from 1989 to 2020, including their mechanism of action whenever applicable. [Display omitted] [ABSTRACT FROM AUTHOR]

Fucales are an order within the Phaeophyceae that include most of the common littoral seaweeds in temperate and subtropical coastal regions. Many species of this order have long been a part of human culture with applications as food, feedand remedies in folk medicine. Apart from their high nutritional value, these seaweeds are also a well-known reservoir of multiple bioactive compounds with great industrial interest. Among them, phlorotannins, a unique and diverse class of brown algae-exclusive phenolics, have gathered much attention during the last few years due to their numerous potential health benefits. However, due to their complex structural features, combined with the scarcity of standards, it poses a great challenge to the identification and characterization of these compounds, at least with the technology currently available. Nevertheless, much effort has been taken towards the elucidation of the structural features of phlorotannins, which have resulted in relevant insights into the chemistry of these compounds. In this context, this review addresses the major contributions and technological advances in the field of phlorotannins extraction and characterization, with a particular focus on Fucales.

The radionuclides released from the nuclear power plants (NPPs) during nuclear accidents can cause severe damage to the marine ecosystems. Strontium (Sr), cobalt (Co), and manganese (Mn) are among the main metal elements in the radionuclide wastes. Living macroalgae have been regarded as efficient materials to scavenge metal ions from polluted water bodies. Given the enormous amount of harvested Sargassum horneri biomass due to the outbreak of "golden tide" along the China's coastline, this study aimed to evaluate its potential in removing Sr, Co, and Mn from seawater. The process, kinetics, and mechanisms of scavenging these metal elements were investigated in the present study. The interaction among these three nuclides during the removal process was also explored. The results showed that living S. horneri biomass was effective at scavenging Sr, Co, and Mn from seawater in both mono- and multi-nuclide contamination scenarios. Notably, the removal efficiency of S. horneri was found to be in the following order: Mn > Co > Sr. Furthermore, the biosorption kinetic data of living S. horneri for Sr, Co, and Mn removal were well described by both pseudo-first-order and pseudo-second-order kinetic models. The removal efficiency of S. horneri on any single nuclide could be influenced by the co-existence with other two nuclides and their concentrations. [ABSTRACT FROM AUTHOR]

In this study, citric acid was applied as a safe organic acid for the treatment of the brown macroalga Sargassum latifolium to facilitate the sequential extraction of fucoidan and alginate without cross contamination. Box-Behnken experimental design was used to investigate the effects of citric acid concentration, temperature, and time on fucoidan yield, its fucose and sulfate contents, and molecular weight (MW), while the investigated responses of the sequentially extracted alginate were yield, mannuronic/guluronic acid ratio (M/G) and MW. Under the optimized conditions, the fucoidan yield, fucose content, sulfate content, and MW were 6.55%, 21.01%, 30.92% and 7.12 × 103 Da, respectively, while alginate yield, M/G, and MW were 28.81%, 0.36, and 1.50 × 105 Da, respectively. The optimized products showed good Fe(III) chelating properties and the iron contents were 509.82 mg g−1 for fucoidan-Fe and 406.71 ± 5.18 mg g−1 for alginate-Fe. Under simulated gastrointestinal conditions, fucoidan-Fe and alginate-Fe complexes released 46 and 57% iron, respectively, which are nutritionally relevant amounts. Both fucoidan and alginate showed potent antioxidant properties, but their Fe complexes exhibited a reduced activity. The results of the present study indicated that citric acid could support the basis for an economical biorefinery process for the sequential extraction of fucoidan and alginate. Additionally, these polysaccharides could be good candidates for the preparations of iron supplements. [ABSTRACT FROM AUTHOR]

Previously it was established that phlorotannins of Arctic brown algae have bactericidal and bacteriostatic effects on Gram-positive and Gram-negative bacteria in aerobic conditions of cultivating in vitro. These effects are due to the presence of active centers in macromolecule (hydroxyl groups) and the degree of polymerization. In this article, the effect of stimulation of the phagocytic activity of human blood neutrophilic leukocytes by studied fractions of Fucus vesiculosus polyphenols was revealed. In vitro, it was found that functional and polymolecular features of polyphenols affect the formation of the complex mechanism of influence on human blood cells. Polyphenols stimulate sorption effects on cells' surface and cause their agglomeration. Effect of erythrocytes, lymphocytes, epitheliocytes, and neutrophils surface modification without disturbing membrane integrity was revealed. Polyphenols of brown algae increase the intensity of the phagocytic reaction of neutrophilic granulocytes. Additionally, intraperitoneal injection of 5 pg mL−1 in outbred white mice (in 1 mL of saline) increased the migration activity of myeloid and lymphoid elements into the peritoneal space. Studied fractions of polyphenols can provide cell cooperation by increasing cluster formation. [ABSTRACT FROM AUTHOR]

Morphology and physiology are two key aspects of the adaptation of kelp to varying environments. Some of these kelp responses to co-occurring highly hydrodynamic condition and high nutrient availability are well documented, but little is known about how these factors affect frond surface shape, particularly in the central frond. In this study, morphological and physiological traits of acclimatized Saccharina latissima (Phaeophyceae) (three size classes: 44.14 ± 1.15 cm, 29.60 ± 0.75 cm, and 16.07 ± 0.45 cm) were compared after 56 days under fully controlled conditions of waves or no waves, and high or low nutrient availability (i.e., LN-NW, LN-W, HN-NW, and HN-W treatments). Waves primarily increased frond biomass, elongation rate, and carbon to nitrogen ratio (C:N ratio) and induced both a greater variety in and rougher frond surface shapes. The fastest, second-fastest, and slowest growth rates were observed in the HN-W, LN-W, and LN-NW treatments, respectively. The highest C:N ratio was observed in the LN-W treatment. Together, these results seem to suggest that the thready and spring-like shapes found in the central frond (i.e., rougher frond surface) in wave-exposed conditions can at least partly compensate for low nutrient availability by enhancing nutrient and photon acquisition, particularly in low nutrient conditions. Additionally, large individuals showed significantly larger and heavier fronds compared with other size classes, and the meristematic sections of fronds had the most variance in frond surface shapes and highest C:N ratios compared with distal and mid-sections. Together, these results indicate that frond surface shapes in the newly formed central frond of S. latissima can be regarded both as possessing high morphological and physiological plasticity that enables kelp to cope with contrasting environments. [ABSTRACT FROM AUTHOR]

A vast diversity of types of life cycles exists in nature, and several theories have been advanced to explain how this diversity has evolved and how each type of life cycle is retained over evolutionary time. Here, we exploited the diversity of life cycles and reproductive traits of the brown algae (Phaeophyceae) to test several hypotheses on the evolution of life cycles. We investigated the evolutionary dynamics of four life‐history traits: life cycle, sexual system, level of gamete dimorphism and gamete parthenogenetic capacity. We assigned states to up to 77 representative species of the taxonomic diversity of the brown algal group, in a multi‐gene phylogeny. We used maximum likelihood and Bayesian analyses of correlated evolution, while taking the phylogeny into account, to test for correlations between traits and to investigate the chronological sequence of trait acquisition. Our analyses are consistent with the prediction that diploid growth evolves when sexual reproduction is preferred over asexual reproduction, possibly because it allows the complementation of deleterious mutations. We also found that haploid sex determination is ancestral in relation to diploid sex determination. However, our results could not address whether increased zygotic and diploid growth are associated with increased sexual dimorphism. Our analyses suggest that in the brown algae, isogamous species evolved from anisogamous ancestors, contrary to the commonly reported pattern where evolution proceeds from isogamy to anisogamy. [ABSTRACT FROM AUTHOR]

The study investigated the Phaeophyceae during the year 2019 at sixteen sampling sites representative for Cham islands. Specimens were collected by scuba diving, snorkelling and walking at the upper tidal zone in both dry and rainy seasons. Twenty-five species of the Phaeophyceae identified for Cham islands from four orders, four families and eleven genera. The Sargassaceae family is the most abundant species composition, followed by Dictyotaceae, Scytosiphonaceae and Asteronemataceae family. In the six islands surveyed, Hon Lao has the highest diversity with 19 species recorded; Hon Dai, Hon Tai, Hon Kho and Hon Mo island recorded from 10 to 14 species, and the lowest diversity is at the Hon La island with 8 species. Ten species Canistrocarpus cervicornis, Dictyota spinulosa, Lobophora obscura, Lobophora variegata, Pandina minor, Sargassum bicorne, Sargassum herklotsii, Sargassum parvifolium, Turbinaria conoides, Asteronema breviarticulatum reported as new records for the marine flora of Cham islands. [ABSTRACT FROM AUTHOR]