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Palisada corallopsis has a widely reported distribution in the western and eastern Atlantic and some areas of the Indo-Pacific Ocean, whereas P. furcata has a more restricted distribution, reported only from Brazil and Cuba. Palisada corallopsis and P. furcata were collected from their type localities, Havana, Cuba and Ceará, Brazil, respectively, and compared by morphological and molecular analyses using rbcL and COI-5P genes. The molecular results placed the sequences from the type locality of both species in the same clade, showing low genetic divergence, 0.95 % for rbcL and 1.6 % for COI-5P. Morphologically, the species share similar habits, with branchlets bi-to trifurcated, cortical cells that may be arranged as a palisade and connected by secondary pit-connections. Our detailed morphological observations, including examination of the type specimens, and molecular analyses demonstrate that P. corallopsis and P. furcata are conspecific, P. furcata being a later taxonomic synonym of P. corallopsis. [ABSTRACT FROM AUTHOR]

To investigate the effects of ocean acidification (OA) and nitrogen limitation on macroalgae growth and photophysiological responses, Gracilariopsis lemaneiformis was cultured under two main conditions: ambient (Low CO2, LC, 390 matm) and CO2 enriched (High CO2, HC, 1000 matm), with low (LN, 7 mmol L-1) and high (HN, 56 mmol L-1) nitrate. High CO2 levels decreased growth under both LN and HN treatments. HC reduced Chl a, carotenoids, phycoerythrin (PE), and phycocyanin (PC) under HN conditions, while only Chl a decreased under LN conditions. NO3 - uptake rate was restricted under LN compared to HN, while HC enhanced it under HN. Net photosynthetic O2 evolution rates did not differ between CO2 and nitrate treatments. Dark respiration rates were higher under HN, further boosted by HC. The stimulated effective quantum yield (Y(II)) corresponded to decreased non-photochemical quenching (NPQ) under HN conditions. Nitrate, not CO2, showed significant effects on the relative electron transport rate (rETRmax), light use efficiency (a) and saturation light intensity (Ik) that with lowered rETRmax and a under LN culture. Our results indicate that OA may negatively affect Gracilariopsis lemaneiformis growth and alter its photophysiological performance under different nutrient conditions. [ABSTRACT FROM AUTHOR]

The experiment was to investigate the effects of three species of macroalgae on the growth performance, physiology and biochemistry index of juvenile largemouth bass. A total of 360 juvenile largemouth bass with an initial body weight of (6.04±0.03) g were randomly divided into four groups with three replicates per group and 30 perca per replicate. Group C (Control Group) was fed a basic diet, while Groups T1, T2, and T3 were fed the basic diet supplemented with 5% Gracilaria lemaneiformis powder, 5% Asparagopsis taxiformis powder, and 5% Sargassum powder, respectively, with each group's diet being isonitrogenous and isocaloric. The experiment lasted for 57 days. The results showed that compared to Group C, the feed intake rate and feed coefficient of all experimental groups was significantly increased (P<0.05), and the protein deposition rate and fat deposition rate of Groups T2 and T3 were significantly decreased (P<0.05). The whole fish moisture content of Groups T2 and T3 was significantly increased (P<0.05), while the crude protein and crude fat concentrations were significantly decreased (P<0.05). The crude fat content in the liver of Groups T2 and T3 was significantly decreased (P<0.05). The study shows that the diet with 5% Gracilaria lemaneiformis powder, Asparagopsis taxiformis powder, and Sargassum powder respectively does not affect the growth of juvenile largemouth bass, but can improve its feeding rate and reduce the crude fat of the whole body and liver, and overall effect of juvenile largemouth bass supplemented with Sargassum powder feed is the best. [ABSTRACT FROM AUTHOR]

Epiphytic algae are important components of marine ecosystems. Despite the importance of epiphytic algae in marine ecosystems, our knowledge of these taxa is still limited. The marine red algal genus Reinboldiella, which is distributed mainly in the northwestern Pacific region, is characterized by tiny thalli that are epiphytic on various other red algae. Six species of the genus have been reported in Japan, Taiwan, and Korea. In this study, 50 Korean Reinboldiella specimens, previously known as Reinboldiella schmitziana, were collected from 11 localities and reexamined to verify their taxo-nomic status. We describe a new species, Reinboldiella koreana sp. nov., based on rbcL phylogeny and morphological observations. A total of four grateloupiacean species (Pachymeniopsis lanceolata, P. elliptica, Grateloupia turuturu, and G. asiatica) were identified as host species of R. koreana sp. nov. Due to the restricted host range of R. koreana sp. nov., a phylogenetic tree was reconstructed using the cox1 marker to confirm the co-phylogenetic relationships between the epiphytic algae and their grateloupiacean hosts. Two of the four cox1 haplotypes of R. koreana were found in different host species, regardless of which haplotype they were. It indicates that there are no co-phylogenetic relationships between R. koreana and host species. [ABSTRACT FROM AUTHOR]

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

This article provides an overview of the diversity and distribution of macroalgae in the Androth Island of the Lakshadweep Archipelago. The study reveals that the island is home to a wide range of algae, with 62 genera and 114 species identified. The most prevalent species are Bryopsis plumosa and Halimeda simulans. The article emphasizes the significance of macroalgae in maintaining ecological balance and biodiversity in the region, while also highlighting the threats they face from climate change, overfishing, and pollution. The authors stress the need for conservation strategies and further research to protect these valuable marine resources. The author, Rekha Govindan, is an experienced academician with expertise in marine biology and has contributed to the scientific community through various publications in biotechnology and related fields. [Extracted from the article]

BACKGROUND: The drive towards ensuring the sustainability of bioresources has been linked with better valorising primary materials and developing biorefinery pipelines. Seaweeds constitute valuable coastal resources with applications in the bioenergy, biofertiliser, nutrition, pharmaceutical and cosmetic sectors. Owing to the various sought‐after metabolites they possess, several seaweed species are commercially exploited throughout Western Europe, including Ireland. Here, four commercially relevant brown (Fucus serratus and Fucus vesiculosus) and red (Chondrus crispus and Mastocarpus stellatus) seaweed species were sampled during a spring tide in July 2021 on moderately exposed shores across three coastal regions in the west of Ireland. RESULTS: Significant regional differences were identified when specimens were analysed for carbohydrates (max. 80.3 μg glucose eq mg−1 DW), proteins (max. 431.3 μg BSA eq. mg−1 DW), lipids (max. 158.6 mg g−1 DW), pigment signature and antioxidant potential. Protein content for F. serratus recorded a twofold difference between northern and southern specimens. The antioxidant potential of F. vesiculosus and M. stellatus returned greater activity compared to F. serratus and C. crispus, respectively. Multivariate analysis showed a clear latitudinal pattern across the three western coastal regions (north, west and south) for both F. vesiculosus and F. serratus. CONCLUSION: F. vesiculosus thalli from the northwest were richer in pigment content while the F. serratus thalli from the northwest were richer in antioxidants. Such biogeographic patterns in the biochemical make‐up of seaweeds need consideration for the development of regional integrated aquaculture systems and the optimisation of the biomass content for targeted downstream applications. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The complex interactions between epiphytic bacteria and marine macroalgae are still poorly understood, with limited knowledge about their community structure, interactions, and functions. This study focuses on comparing epiphytic prokaryotes community structure between three seaweed phyla; Chlorophyta, Rhodophyta, and Heterokontophyta in an easternmost rocky intertidal site of the Mediterranean Sea. By taking a snapshot approach and simultaneously collecting seaweed samples from the same habitat, we minimize environmental variations that could affect epiphytic bacterial assembly, thereby emphasizing host specificity. Through 16S rRNA gene amplicon sequencing, we identified that the microbial community composition was more similar within the same seaweed phylum host compared to seaweed host from other phyla. Furthermore, exclusive Amplicon Sequence Variants (ASVs) were identified for each algal phyla despite sharing higher taxonomic classifications across the other phyla. Analysis of niche breadth indices uncovers distinctive affinities and potential specialization among seaweed host phyla, with 39% of all ASVs identified as phylum specialists and 13% as generalists. Using taxonomy function prediction, we observed that the taxonomic variability does not significantly impact functional redundancy, suggesting resilience to disturbance. The study concludes that epiphytic bacteria composition is connected to host taxonomy, possibly influenced by shared morphological and chemical traits among genetically related hosts, implying a potential coevolutionary relationship between specific bacteria and their host seaweeds. [ABSTRACT FROM AUTHOR]

Four species of the genus Wrangelia are presently known from the western Atlantic Ocean: W. argus, W. bicuspidata, W. penicillata, and W. gordoniae, with the first three historically being reported from Bermuda. Morphological and molecular barcode (COI‐5P) and phylogenetic analyses used in this study (SSU, LSU, rbcL) indicated eight species groupings of Wrangelia in Bermuda, excluding two of the historically recognized species, retaining only W. argus while adding seven new species, of which six are formally described. What had been historically reported as W. penicillata from Bermuda was shown to be distinct from Mediterranean Sea specimens (type locality) and was shown to be a mixture of W. hesperia sp. nov. and W. incrassata sp. nov. Along with these two, three other new species (W. laxa sp. nov., W. ryancraigii sp. nov., and W. secundiramea sp. nov.) have complete rhizoidal cortication tightly covering axial cells of indeterminate axes below the apices, distinguishing them from the two local incompletely corticated congeners W. argus and W. abscondita sp. nov., the latter a morphologically cryptic sister species with W. bicuspidata from the Caribbean Sea. Only one of the new species, W. ryancraigii, has thus far been observed in the mesophotic zone off the Bermuda platform, and it is morphologically cryptic with the euphotic zone's W. laxa. [ABSTRACT FROM AUTHOR]

Aim: Genetic diversity of marine forests results from complex interactions of eco‐evolutionary processes. Among them, oceanographic connectivity driven by dispersal through water transport is hypothesized to play a pivotal role, yet its relative contribution has not been addressed at the global scale. Here, we test how present‐day oceanographic connectivity is correlated with the distribution of genetic diversity of marine forests across the ocean. Location: Global. Time period: Contemporary. Major taxa studied: Marine forests of brown macroalgae (order: Fucales, Ishigeales, Laminariales and Tilopteridales). Methods: Through literature review, we compiled a comprehensive dataset of genetic differentiation, encompassing 699 populations of 30 species. A biophysical model coupled with network analyses estimated multigenerational oceanographic connectivity and centrality across the marine forest global distribution. This approach integrated propagule dispersive capacity and long‐distance dispersal events. Linear mixed models tested the relative contribution of site‐specific processes, connectivity and centrality in explaining genetic differentiation. Results: We show that spatiality‐dependent eco‐evolutionary processes, as described by our models, are prominent drivers of genetic differentiation in marine forests (significant models in 91.43% of the cases with an average R2 of 0.50 ± 0.07). Specifically, we reveal that 18.7% of genetic differentiation variance is explicitly induced by predicted contemporary connectivity and centrality. Moreover, we demonstrate that long‐distance dispersal is key in connecting populations of species distributed across large water masses and continents. Main conclusions: Our findings highlight the role of present‐day oceanographic connectivity in shaping the extant distribution of genetic diversity of marine forests on a global scale, with significant implications for biogeography and evolution. This understanding can pave the way for future research aimed at guiding conservation efforts, including the designation of well‐connected marine protected areas, which is particularly relevant for sessile ecosystems structuring species such as brown macroalgae. [ABSTRACT FROM AUTHOR]

Macroalgae seaweeds such as Ulva lactuca and Gracilaria verrucosa cause problems on the northern coast of the Italian Adriatic Sea because their overabundance hinders the growth of cultivated clams, Rudatapes philippinarum. This study focused on the green synthesis of CuO nanoparticles from U. lactuca and G. verrucosa. The biosynthesized CuO NPs were successfully characterized using FTIR, XRD, HRTEM/EDX, and zeta potential. Nanoparticles from the two different algae species are essentially identical, with the same physical characteristics and almost the same antimicrobial activities. We have not investigated the cause of this identity, but it seems likely to arise from the reaction of Cu with the same algae metabolites in both species. The study demonstrates that it is possible to obtain useful products from these macroalgae through a green synthesis approach and that they should be considered as not just a cause of environmental and economic damage but also as a potential source of income. [ABSTRACT FROM AUTHOR]

In this study, we evaluated Electrical Impedance Spectroscopy (EIS) as a monitoring tool of the physiological state of Bryopsis, Cystoseira, Stypopodium, Cladophora, Taonia, Padina, Ulva and Sargassum tissues. We analyzed the electrical response differences in the EIS between species and in the same seaweed tissue before and after electroporation. Electroporation using high voltage pulsed electric field (PEF) treatment was used as a model for cell disruption affecting the tissue physiology without being noticeable to the naked-eye. Significant differences in all the seaweeds were observed before and after electroporation. We found that seaweed species with smaller and rounder cells have a clearer dispersion profile (around a frequency of 10–100 kHz) compared to the dispersion profile of seaweed with larger cells with unround form. Those results suggest that EIS could be used as a fast non-invasive monitoring technique of the changes in the physiology of seaweeds. [ABSTRACT FROM AUTHOR]

AbstractUlva, a genus of green macroalgae commonly known as sea lettuce, has long been recognized for its nutritional benefits for food and feed. As the demand for sustainable food and feed sources continues to grow, so does the interest in alternative, plant-based protein sources. With its abundance along coastal waters and high protein content, Ulva spp. have emerged as promising candidates. While the use of Ulva in food and feed has its challenges, the utilization of Ulva in other industries, including in biomaterials, biostimulants, and biorefineries, has been growing. This review aims to provide a comprehensive overview of the current status, challenges and opportunities associated with using Ulva in food, feed, and beyond. Drawing on the expertise of leading researchers and industry professionals, it explores the latest knowledge on Ulva’s nutritional value, processing methods, and potential benefits for human nutrition, aquaculture feeds, terrestrial feeds, biomaterials, biostimulants and biorefineries. In addition, it examines the economic feasibility of incorporating Ulva into aquafeed. Through its comprehensive and insightful analysis, including a critical review of the challenges and future research needs, this review will be a valuable resource for anyone interested in sustainable aquaculture and Ulva’s role in food, feed, biomaterials, biostimulants and beyond. [ABSTRACT FROM AUTHOR]

The algae of the genus Gelidium can be found as frequent and abundant inhabitants in the rocky intertidal zone of the Mexican Atlantic. Six species of this genus have been reported in this region, but only Gelidium americanum has been confirmed with morphological and molecular tools, despite how important both tools have proven to be for the group. This research aimed to evaluate the Mexican specimens previously identified as Gelidium through morphological and molecular approaches, using rbcL and COI-5P markers. This study examined 20 specimens found living attached to the shell of a gastropod Stramonita rustica in the mid-high intertidal zone of the Mexican Atlantic and ten specimens found living on rocks. Phylogenetic analyses resolved these specimens to be an independent species closely related to G. gonzalezii, G. yangmeikengense, and G. indonesianum. Genetic distances and morphological information confirmed this. Gelidium rodrigueziae sp. nov. is described as a new species. It is distinguished from its related species by having a simpler branching pattern, a smaller number and size of medullary cells, and the smaller quantity and distribution of restricted internal rhizoid filaments around the medulla. [ABSTRACT FROM AUTHOR]

The current study sought to determine the effects of Colpomenia sinuosa and Sargassum linifolium aqueous extracts on non-enzymatic and enzymatic antioxidants in Spinacia oleracea L. leaf extract. Glutathione synthase (GSS, EC: 6.3.2.3) and -glutamyl cysteine synthetase (-GCS, EC: 6.3.2.2) are involved in the glutathione biosynthesis process. Treatment of S. oleracea with seaweed extracts increased the level of reduced glutathione (GSH), oxidized glutathione (GSSG), and total glutathione at lower concentrations. Total phenols and total flavonoids in S. oleracea leaves accumulated more rapidly after treatment with seaweed extracts. The activity of the enzyme’s phenylalanine ammonia lyase (PAL, EC: 4.3.1.25), chalcone synthase (CHS, EC: 2.3. 1.74), and chalcone isomerase (CHI, EC: 5.5.1.6) involved in the production of phenylpropanoid and flavonoid in S. oleracea leaves rose in a dose-dependent manner. Glutathione reductase (GR, EC 1.6.4.2), glutathione peroxidase (GPX, EC: 1.11.1.9), and glutathione-S-transferase (GST, EC: 2.5.1.18) are examples of antioxidant enzymes whose activity were also elevated by the treatment. In comparison to untreated plants, the treated plants' S. oleracea leaf extract significantly reduced superoxide anion, 1, 1-diphenyl-2-picrylhydrazyl (DPPH), and hydroxyl radicals. In light of this, the current findings imply that the use of seaweed extracts was found to boost the activity of the antioxidant system in Spinacea oleracea [ABSTRACT FROM AUTHOR]

The leaves of Thalassia testudinum provide an ideal substrate for the establishment of small-sized algae with different morphologies that are abundant and diverse. There are few studies on epiphytism in Mexico, and most of them are floristic lists. The objective of this study was to analyze the taxonomic and morphofunctional composition of epiphytes in three climatic seasons, and their relationship with the phorophyte T. testudinum in two localities, El Uvero and Santa Rosa, in the south of Quintana Roo; three transects and fifteen quadrants were set in June and December (2014) and April (2015). A total of 84 epiphytic species were identified: 27 corresponded to Cyanobacteria, 10 to Phaeophyceae, 9 to Chlorophyta, and 38 to Rhodophyta. The highest specific richness was observed in Santa Rosa (73 species). The dry and summer rains seasons share a higher number of species compared to the winter rainy season. The crusty algae Hydrolithon farinosum was the dominant and most persistent species; in addition, filamentous algae presented great specific richness and coverage due to their morphology and reproductive strategies, which allowed them to successfully establish themselves on the phorophyte. This is related to the ecological succession of the epiphytes and seagrass phenology. [ABSTRACT FROM AUTHOR]

We carried out an in-depth study on structural characteristics, both primary and conformational structure in solution of a novel sulfated polysaccharide from green seaweed Codium geppiorum collected in central coast of Vietnam. Primary structure of the polysaccharide was determined mainly by NMR spectra, while conformation was elucidated by using small-angle X-ray scattering method. The polysaccharide was evaluated for its cytotoxic effects on three human cancer cell lines. The results indicated that dominant structure of Codium geppiorum polysaccharide is a linear sulfated galactan, and it was composed of → 4)-β-D-Galp3S-(1 → , → 3)-β-D-Galp4S-(1 → and → 3)-β-D-Galp-(1 → residues connected through 1,3-linkages. The polysaccharide has a rodlike conformation in aqueous solution, and it shows chain association with cross-sectional radius of gyration, Rgc, around 0.70 nm as estimated from small-angle X-ray scattering measurements. The polysaccharide exhibited a significant cytotoxic activity against HT29 (colorectal adenocarcinoma), 8505c (undifferentiated thyroid carcinomas) and Hela (cervical cancer) human cancer cell lines with IC50 values of 51.85 ± 2.30, 89.30 ± 2.35 and 72.22 ± 6.73 µg/mL, respectively. [ABSTRACT FROM AUTHOR]

Seaweed, a valuable marine resource widely cultivated worldwide, can be vulnerable to stress and microbiome alterations, resulting in the decay of seaweeds and substantial economic losses. To investigate the seaweed-microbiome interaction, our study aimed to isolate marine bacteria and fungi that can cause Ice–Ice disease and evaluate their enzymatic characteristics for potential application in bioethanol production from seaweed biomass. Three red seaweed species (Gracilaria edulis, Kappaphycus alvarezii, and Eucheuma cottonii) were obtained for our study and placed in separate culture tanks. Among the 18 isolated marine microbial species, 12 tested positive for agar and carrageenan activity: six exhibited both activities, three displayed only agar activity, and three only carrageenan activity. DNA sequencing of the positive microbes identified ten bacteria and two yeast species. The 3,5-Dinitrosalicylic acid (DNSA) assay results revealed that the identified bacterial Caldibacillus kokeshiiformis strain FJAT-47861 exhibited the highest carrageenase activity (0.76 units/ml), while the yeast Pichia fermentans strain PM79 demonstrated the highest agarase activity (0.52 units/ml). Notably, Pichia fermentans strain PM79 exhibited the highest overall agarase and carrageenase activity, averaging 0.63 units/ml. The average carrageenase activity of all six positive microbes was 1.5 times higher than their agarase activity. These findings suggest that the 12 isolated microbes hold potential for bioethanol production from macroalgae, as their agarase and carrageenase activity indicates their ability to break down seaweed cell wall carbohydrates, causing ice–ice disease. Moreover, these results provide exciting prospects for harnessing the bioconversion capabilities of these microbes, paving the way for sustainable and efficient bioethanol production from seaweed resources. [ABSTRACT FROM AUTHOR]

Intertidal macroalgae play a vital role in marine ecosystems, necessitating effective monitoring of their coverage and diversity. Traditional monitoring methods are labour-intensive and costly, prompting exploration of the use of unmanned aerial vehicles (UAVs) to characterize intertidal ecosystems. We propose an alternative process integrating UAV red-green-blue (RGB) imagery and topographic indexes to classify complex intertidal macroalgae assemblages automatically. We studied two intertidal areas capturing eight flights between May and September 2023. Orthoimages and Digital Elevation Models (DEMs) were generated. Manual segmentations for 24 classes were cropped into images of individual labels. Additional channels with five topographic indices were added to the RGB images. The resulting dataset of 6412 images was then used to train a Convolutional Neural Network (CNN). We tested the benefit of the additional topographic indices by training the CNN with and without the topographic channels. The best results were given by the inclusion of the Analytical hillshade to the RGB images, showing a relative 11.3% increase in classification accuracy. This indicates that 3D data can enhance the performance of macroalgae classification models. However, there was no significant improvement when using more than one topographic index to train the CNN. Our workflow offers a cost-effective and robust solution for intertidal macroalgae monitoring, contributing to ecological conservation efforts. [ABSTRACT FROM AUTHOR]

Environmental context: Seaweeds are known to accumulate high levels of arsenic, and cellular concentrations may reach several orders of magnitude higher than that of the surrounding environment. Arsenic may be methylated by seaweed cells and further metabolised to water-soluble arsenic-containing sugars through unknown pathways. Whether these compounds are the result of a detoxification process or are produced with a biological purpose remains to be seen. Rationale: Seaweeds are known to accumulate high levels of arsenic, which may be subsequently metabolised to small, methylated compounds or become incorporated into large biological molecules such as arsenosugars. The mechanism of arsenosugars production in macroalgae is still largely unknown. Method: This study reports the arsenic speciation of 13 brown, red and green macroalgae collected in May 2021 and February 2022. Water-soluble arsenic speciation was measured using high-performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC-ICP-MS) after extraction with a 3% (v/v) hydrogen peroxide solution. Results: Arsenosugars were found to account for the majority of the extracted arsenic in all seaweed samples (>50%), with only small amounts of dimethylarsinate and monomethylarsonate present. Levels of toxic iAs were also low (−1). Sulfur-containing arsenosugars were the dominant arsenicals in brown macroalgae, whereas the phosphate ribose was most abundant in red and green. Discussion: The majority of seaweed species appear to have the ability to synthesise all four arsenosugar derivatives; however, it is unclear why some are produced in higher abundances. The production of arsenosugars may be an efficient way of excluding arsenic from the cytosol, or may serve as useful components in the cell wall matrix, as extremely high levels can be tolerated by the seaweed with no ill effects. AsSug-gly and AsSug-PO4 were detected in every sample analysed, which might suggest that AsSug-gly is the starting point for AsSug-PO4, which could be formed by AsSug-gly binding to phosphate-containing lipids in the cell membrane. Further studies should use both imaging and speciation techniques to investigate the formation of arsenosugars. Environmental context. Seaweeds are known to accumulate high levels of arsenic, and cellular concentrations may reach several orders of magnitude higher than that of the surrounding environment. Arsenic may be methylated by seaweed cells and further metabolised to water-soluble arsenic-containing sugars through unknown pathways. Whether these compounds are the result of a detoxification process or are produced with a biological purpose remains to be seen. (Image credit: Rebecca Sim.) [ABSTRACT FROM AUTHOR]

In this study, we investigated the physiological and biochemical responses of Ulva species to variation in nutrient availability. Sampling was conducted at two sites on Jeju Island, Korea, namely, Handong, which is close to seven intensive land-based fish farms, and Hado, which has no apparent nearby nutrient sources. We examined the water column nutrient concentrations, nitrate reductase (NR) activity, nitrate uptake efficiency, tissue C, N, and P content, and stable isotope ratios of Ulva species. Water column NH4+, NO3− + NO2−, and PO43− concentrations were significantly higher at Handong than at Hado. NR activity and tissue N content of Ulva species were significantly higher at Handong than at Hado. Notably, nitrate uptake efficiency was inversely proportional to NR activity and tissue N content. The physiological and biochemical responses of Ulva species were closely related to dissolved inorganic nitrogen, which stimulates Ulva species to regulate growth. Additionally, the δ15N values of Ulva tissues at both sites were within the previously reported range for fresh groundwater. Therefore, the main nitrogen source for Ulva growth may be submerged groundwater with high nutrient concentrations. Our results provide invaluable information for estimating dissolved inorganic nitrogen levels in water, which may facilitate development of management policies. [ABSTRACT FROM AUTHOR]

Macroalgal wracks can be considered unpleasant for beach users and, consequently, they are usually collected from most touristic beaches and discarded. However, seaweeds are an important source of bioactive lipid compounds, such as phospholipids, glycolipids, and n-3 polyunsaturated fatty acids (n-3 PUFA), displaying multiple health-promoting properties, including antioxidant and antimicrobial activities. The aim of this study is to characterize the lipid composition of twelve marine seaweed species (two green, six red, and four brown species) from macroalgal wracks of Gran Canaria Island, and to evaluate their potential use for several purposes, including human and animal nutrition. Lipid content, lipid classes, and fatty acid profiles of isolated specimens from the macroalgal wracks were determined. Lipid contents ranged between 0.27 and 3.17% of dry weight, with all species showing high phytosterols proportions and balanced omega-6/omega-3 (n-6/n-3) ratios. In addition, Cymopolia barbata, Asparagopsis sp., and Hypnea spinella seem to be an attractive source of both mono- and di-galactosyl-diacylglycerols, while A. stellata, Jania sp., and Lobophora sp. are relatively rich in n-3 LC−PUFA. Finally, both green algae showed the most favorable values for the nutritional indicators of cardiovascular health promotion. Overall, the macroalgal species analyzed could be considered as interesting sources for human and animal nutrition. [ABSTRACT FROM AUTHOR]

There has been a limited number of studies on the effects of harmful algal blooms (HABs) on natural rocky intertidal ecosystems. From mid-September to early November 2021, an unprecedented HAB caused by Karenia selliformis hit the Pacific coast of southeast Hokkaido, Japan, for the first time, causing massive mortalities among marine organisms. To clarify the immediate impacts of the HAB on the abundance of 10 rocky intertidal species in four functional groups (macroalgae, sessile invertebrates, molluscan grazers, and molluscan carnivores), we focused on two questions: (1) How did the HAB affect the abundance of each species differently at the regional scale? and (2) How did the impacts of the HAB on the abundance of each functional groups vary spatially, and was the spatial variation of the HAB impacts related to the spatial distribution of the cell density of HAB species? To study these issues, we compared census data for 17 years before the HAB and within one month after it for five shores on the southeast coast of Hokkaido. The results showed that two macroalgae species and all three molluscan grazer species declined significantly after the HAB. Moreover, the decrease in molluscan grazers was significantly correlated with cell density. These results suggest that the impacts of the HAB in southeast Hokkaido on the abundance of rocky intertidal organisms are highly variable depending on species and locality, presumably because of differences in species-specific tolerances to HAB toxins and the spatial variation in the density of the HAB organisms. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the current study was to examine the effectiveness of green macroalgae as a novel, natural feed additive for broilers that have a greater concentration of active ingredients. Materials and Methods: Four experimental groups of 180-day-old male broiler chicks (Cobb-500) were randomly assigned, with three replicates in each group: the control group [T0, maintained only with basal diet] and three treatment groups supplemented with macroalgae for 35 days along with basal diet [T1 = 0.05% (w/w); T2 = 0.1% (w/w); T3 = 0.2% (w/w) macroalgae]. Live weight, carcass weight, and organs' weight were noted at the conclusion of the experiment. The meat quality was examined using the muscles of the thighs and breasts, and blood serum was obtained for biochemical assessment. Results: The results revealed that dietary supplementation of green macroalgae (0.1%) in broiler rations significantly (p < 0.05) improved the growth performance compared to other treated groups and controls. With increasing weight, it enhanced meat quality traits assessed by increased water holding capacity, ultimate pH, redness and yellowness, and decreased lightness of muscles in the thighs and breasts. Both the levels of serum cholesterol and abdominal fat decreased and showed no unwholesome effects on liver and kidney functions. Conclusions: For the production of safe and high-quality poultry meat, marine green macroalgae (Enteromorpha intestinalis) could be used as a potential feed additive. It enhanced the growth rate in broilers and improved meat quality and serum biochemical parameters for supplying healthy meat in the human food chain. [ABSTRACT FROM AUTHOR]

The bacterial communities related to seaweed can vary considerably across different locations, and these variations influence the seaweed's nutrition, growth, and development. To study this further, we evaluated the bacteria found on the green marine seaweed Ulva prolifera from Garorim Bay and Muan Bay, two key locations on Republic of Korea's west coast. Our analysis found notable differences in the bacterial communities between the two locations. Garorim Bay hosted a more diverse bacterial population, with the highest number of ASVs (871) compared to Muan Bay's 156 ASVs. In Muan Bay, more than 50% of the bacterial community was dominated by Pseudomonadota. On the other hand, Garorim Bay had a more balanced distribution between Bacteroidota and Pseudomonadota (37% and 35.5%, respectively). Additionally, Cyanobacteria, particularly Cyanothece aeruginosa, were found in significant numbers in Garorim Bay, making up 8% of the community. Mineral analysis indicated that Garorim Bay had higher levels of S, Na, Mg, Ca, and Fe. Function-wise, both locations exhibited bacterial enrichment in amino acid production, nucleosides, and nucleotide pathways. In conclusion, this study broadens our understanding of the bacterial communities associated with Ulva prolifera in Korean waters and provides a foundation for future research on the relationships between U. prolifera and its bacteria. [ABSTRACT FROM AUTHOR]

Groundnut, Arachis hypogaea L., is a leguminous crop widely cultivated for its edible oil seeds. It faces significant challenges from soil-borne diseases, including Sclerotium rolfsii Sacc., which severely affect groundnut production and productivity. Biological control methods offer broader treatment alternatives than traditional chemical approaches. The present study investigated the activation of defense enzymes such as peroxidase (PO), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) in groundnut plants under pot culture conditions. The plants were treated with different marine macroalgae and bioagent combinations, where inoculation with S. rolfsii was challenged. Among the nine treatments, T4 {seed treatment [ST] by Sargassum wightii extract at 2% + soil application (SA) of S. wightii at 100 g/pot + ST by Trichoderma asperellum (Tr-3) at 4 g/kg of seeds + SA with T. asperellum (Tr-3) at 50 g/pot} concentrations gave the maximum increased activities of PO (1.40 changes in absorbance min/g of leaf tissue), PPO (2.03 changes in absorbance min/g of leaf tissue), and PAL (9.56 changes in absorbance min/g of leaf tissue). In contrast, the inoculated control exhibited minimal activity of these enzymes. The increased enzyme activities were recorded until 24 days after sowing, and a gradual decrease was observed afterward. The present study showed that marine macroalgae and bioagents could enhance defense enzyme activity in groundnut plants and significantly prevent the disease caused by S. rolfsii. [ABSTRACT FROM AUTHOR]

The epipelagic macroalgae of Ulva prolifera and Sargassum are the primary contributors to widespread seaweed tides globally. Both ocean plants release large amounts of chromophoric dissolved organic matter (CDOM) into the surrounding seawater. The photochemical reactivity of this CDOM, however, has not been adequately addressed. In this study, we extracted CDOM from Ulva prolifera and Sargassum, examined their ultraviolet (UV)-visible absorption characteristics, and quantified their broadband apparent quantum yields (AQY) of absorbance photobleaching and photomineralization (in terms of CO2, CO, and CH4 photoproduction). On a per-unit-weight basis, Sargassum leached 3.5 times more CDOM than did Ulva prolifera in terms of the absorption coefficient averaged over 254-500 nm. Both Ulva prolifera and Sargassum CDOM were characterized by quasi-exponential decay absorption spectra, with Sargassum CDOM exhibiting a distinct shoulder over 310-350 nm suggestive of mycosporine amino acids. The Sargassum CDOM had a higher photobleaching AQY but lower photomineralization AQYs compared to Ulva prolifera CDOM. The photobleaching and photomineralization AQYs of both macroalgal CDOM are, however, orders of magnitude higher than those of CDOM in various natural waters. Potential photoproduction rates of CO2 and CO from the Ulva prolifera CDOM and Sargassum CDOM during the bloom periods are several times to orders of magnitude higher than the air-sea fluxes of these gases in the absence of the macroalgae. This study demonstrates that CDOM released by Ulva prolifera and Sargassum is extremely prone to photobleaching and photomineralization, rendering floating mats of these plants in oceans as potential "hotspots" of greenhouse gas emissions to the atmosphere. This photochemical feedback should be considered when assessing ocean afforestation as a CO2 removal approach to mitigate climate warming. [ABSTRACT FROM AUTHOR]

The drug target protein β-secretase 1 (BACE1) is one of the promising targets in the design of the drugs to control Alzheimer's disease (AD). Patients with neurodegenerative diseases are increasing in number globally due to the increase in the average lifetime. Neuro modulation is the only remedy for overcoming these age related diseases. In recent times, marine bioactive compounds are reported from Phaeophyceae (Brown Algae), Rhodophyta (Red Algae) and Chlorophyta (Green Algae) for neuro-modulation. Hence, an important attempt is made to understand the binding and stability of the identified bioactive compounds from the above marine algae using BACE1 as the molecular target. The docking study shows that the bioactive compound Fucotriphlorethol A (– 17.27 kcal/mol) has good binding affinity and energy compared to other compounds such as Dieckol (– 16.77 kcal/mol), Tetraphlorethol C (– 15.12 kcal/mol), 2-phloroeckol (– 14.98 kcal/mol), Phlorofucofuroeckol (– 13.46 kcal/mol) and the co-crystal (– 8.59 kcal/mol). Further, molecular dynamics simulations studies had been carried out for β-secretase 1 complex with Fucotriphlorethol A and Phlorofucofuroeckol for 100 ns each. Results are compared with that of the co-crystal inhibitor. Molecular dynamics simulations studies also support the stability and flexibility of the two bioactive compounds Fucotriphlorethol A and Phlorofucofuroeckol with BACE1. [ABSTRACT FROM AUTHOR]

In this study, extraction conditions of proteins from Sargassum vulgare were optimized. The Box-Behnken design (BBD)-based Response Surface Methodology (RSM) was used to investigate and optimize the protein content (PC), total phenolic content (TPC), and antioxidant activity (AOA), which were affected by extraction parameters (ultrasonic probe time: 0.09-2.91 min and enzyme/substrate ratio (E/S): 0.18-1.02). The optimal extraction was achieved while applying an ultrasonic probe for 2.5 min and using an E/S of 0.90. Under this optimum conditions PC and TPC were found to be as 248.30 mg protein/g dry weight (dw) and 38.03 mg gallic acid equiavalent (GAE)/g dw, respectively. Moreover, AOA was determined to be 53.77 mg Trolox equivalent (TE)/g dw by CUPRAC and 19.88 mg TE/g dw by ABTS methods. These findings provide a good basis for future research into the potential of macroalgae protein extracts, which have a high protein content and antioxidant potential for food industry. [ABSTRACT FROM AUTHOR]

The crustose coralline alga Lithophyllum stictiforme is an important reef builder, forming coralligenous concretions in the Mediterranean Sea. This algal species complex is composed of eight cryptic species (or clades). The objective of our study was to compare light-dependent physiological processes within and between the two most abundant cryptic species (C1 and C4) of L. stictiforme from the Bay of Marseille (France). Physiological rates of respiration, photosynthesis and calcification were measured using incubation chambers under various irradiance levels and in the dark during the summer period. We compared the physiology of the C1 and C4 cryptic species of L. stictiforme among three algal groups: C1 (the most common in the Marseille area) from 28 m depth, C4 from the same site and depth, and C1 from a deeper site at 45 m depth. We found both interspecific (between C1 and C4) and intraspecific (within C1) physiological differences. Photosynthetic parameters showed acclimation to light (or depth) with higher values of initial slope of photosynthetic light response curve (α) and lower values of saturating irradiance (Ek) and compensating irradiance (Ec) for C1 from 45 m than for C1 and C4 from 28 m depth. At the shallower depth, significant physiological differences were observed between C1 and C4 with a higher value of maximum rate of gross photosynthesis (Pg max) in C4, suggesting better ability to grow under high irradiance. Light and dark calcification rates differed only between C4 from 28 m and C1 from 45 m depth, being intermediate in C1 from 28 m depth. On a 24 h basis, diel net calcification rates were significantly higher in specimens from the shallower waters than from the deeper waters. Physiological differences suggest physiological plasticity within the regionally dominant cryptic species C1 and species-specific physiological traits between the cryptic species C1 and C4. Photosynthesis and calcification rates differ among Lithophyllum stictiforme cryptic species. The regionally dominant cryptic species exhibits light-dependent physiological plasticity. Physiological differences occur between cryptic species found in similar environments. [ABSTRACT FROM AUTHOR]

This study presents a green method of producing copper nanoparticles (CuNPs) using aqueous extracts from Sargassum spp. as reducing, stabilizing, and capping agents. The CuNPs created using this algae‐based method are not hazardous, they are eco‐friendly, and less toxic than their chemically synthesized counterparts. The XRD characterization of the CuNPs revealed the presence of Cu and CuO, with a crystallite size ranging from 13 to 17 nm. Following this, the CuNPs were supported onto a carbon substrate, also derived from Sargassum spp. (biochar CSKPH). The CuNPs in biochar (CuNPs‐CSKPH) did not appear in the XRD diffractograms, but the SEM‐EDS results showed that they accounted for 36 % of the copper weight. The voltamperometric study of CuNps‐CSKPH in acid media validated the presence of Cu and the amount was determined to be 2.58 μg. The catalytic activity of CuNPs‐CSKPH was analyzed for the electrochemical reduction of CO2. The use of Sargassum spp. has great potential to tackle two environmental problems simultaneously, by using it as raw material for the synthesis of activated biochar as support, as well as the synthesis of CuNPs, and secondly, by using it as a sustainable material for the electrochemical conversion of CO2. [ABSTRACT FROM AUTHOR]

The genus Visia is reappraised based on new morphological and molecular data (rbcL and COI-5P sequences), from recently collected and previously studied materials, resulting in the need for several taxonomic changes. Based on our phylogeny and sequence divergence, the genus Visioidea gen. nov. is proposed for two samples from Brazil, forming a distinct clade that is morphologically undistinguishable from the generitype of Visia (V. cayennensis). Two lineages of Visia with high genetic divergences from other species are proposed as new species: 1) V. verviridis sp. nov. from Australia; 2) V. amazonensis sp. nov. from Brazil. Although genetically distinct, both species are morphologically very similar to V. cayennensis. A new record of V. cylindrocellularis was found in Australia, expanding the geographic distribution and the morphometric ranges for this species. The number of species currently recognized in Visia is now six, four with DNA sequence data and two identified based solely on morphology (V. longiarticulata and V. turgida). Cryptic genera within the order Batrachospermales were not recognised until recently with the proposals of Volatus, morphologically indistinct from Kumanoa, and Macrosporophycos undistinguishable from Montagnia and here a third cryptic genus Visioidea is described. [ABSTRACT FROM AUTHOR]

Nature derived compounds represent a valuable source of bioactive molecules with enormous potential. The sea is one of the richest environments, full of skilled organisms, where algae stand out due to their unique characteristics. Marine macroalgae adapt their phenotypic characteristics, such as chemical composition, depending on the environmental conditions where they live. The compounds produced by these organisms show tremendous potential to be used in the biomedical field, due to their antioxidant, anti-inflammatory, immunomodulatory, and anti-cancer properties. Cancer is one of the deadliest diseases in the world, and the lack of effective treatments highlights the urgent need for the development of new therapeutic strategies. This review provides an overview of the current advances regarding the anti-cancer activity of the three major groups of marine macroalgae, i.e., red algae (Rhodophyta), brown algae (Phaeophyceae), and green algae (Chlorophyta) on pancreatic, lung, breast, cervical, colorectal, liver, and gastric cancers as well as leukemia and melanoma. In addition, future perspectives, and limitations regarding this field of work are also discussed. [ABSTRACT FROM AUTHOR]

In response to a global shift towards health-conscious and environmentally sustainable food choices, seaweed has emerged as a focus for researchers due to its large-scale cultivation potential and the development of bioactive substances. This research explores the potential anticancer properties of seaweed extracts, focusing on analyzing the impact of four common edible seaweeds in Taiwan on prostate cancer (PCa) cells' activity. The study used bioassay-guided fractionation to extract Cl80 from various seaweeds with androgen receptor (AR)-inhibitory activity. Cl80 demonstrated effective suppression of 5α-dihydrotestosterone (DHT)-induced AR activity in 103E cells and attenuated the growth and prostate-specific antigen (PSA) protein expression in LNCaP and 22Rv1 cells. Additionally, Cl80 exhibited differential effects on various PCa cell lines. Concentrations above 5 μg/mL significantly inhibited LNCaP cell proliferation, while 22Rv1 cells were more resistant to Cl80. PC-3 cell proliferation was inhibited at 5 μg/mL but not completely at 50 μg/mL. A clonogenic assay showed that at a concentration of 0.5 μg/mL, the colony formation in LNCaP and PC-3 cells was significantly reduced, with a dose-dependent effect. Cl80 induced apoptosis in all PCa cell types, especially in LNCaP cells, with increased apoptotic cells observed at higher concentrations. Cl80 also decreased the mitochondrial membrane potential (ΔΨm) in a dose-dependent manner in all PCa cell lines. Furthermore, Cl80 suppressed the migration ability of PCa cells, with significant reductions observed in LNCaP, 22Rv1, and PC-3 cells at various concentrations. These compelling findings highlight the promising therapeutic potential of C. lentillifera J.Agardh and its isolated compound Cl80 in the treatment of PCa. [ABSTRACT FROM AUTHOR]

This study presents a green method of producing copper nanoparticles (CuNPs) using aqueous extracts from Sargassum spp. as reducing, stabilizing, and capping agents. The CuNPs created using this algae‐based method are not hazardous, they are eco‐friendly, and less toxic than their chemically synthesized counterparts. The XRD characterization of the CuNPs revealed the presence of Cu and CuO, with a crystallite size ranging from 13 to 17 nm. Following this, the CuNPs were supported onto a carbon substrate, also derived from Sargassum spp. (biochar CSKPH). The CuNPs in biochar (CuNPs‐CSKPH) did not appear in the XRD diffractograms, but the SEM‐EDS results showed that they accounted for 36 % of the copper weight. The voltamperometric study of CuNps‐CSKPH in acid media validated the presence of Cu and the amount was determined to be 2.58 μg. The catalytic activity of CuNPs‐CSKPH was analyzed for the electrochemical reduction of CO2. The use of Sargassum spp. has great potential to tackle two environmental problems simultaneously, by using it as raw material for the synthesis of activated biochar as support, as well as the synthesis of CuNPs, and secondly, by using it as a sustainable material for the electrochemical conversion of CO2. [ABSTRACT FROM AUTHOR]

Featured Application: Firstly, it is an extensive review of one of the most talked about "hot topics" today. Subsequently, it could be a complete guide to the cultivation and use for aquaculture of one of the most cosmopolitan species ever, as well as a guide to controlling "green tides". Green algae, phylum Chlorophyta, due to their green appearance as higher plants, are seen as one of the raw materials to be widely used by humanity for different purposes. How can these different purposes achieve ONU Sustainable Development Goals? The genus Ulva sp. is widely distributed through all continents, tolerating different ecosystems (freshwater and marine), different intensities of light, temperature, and salinity. The Ulva sp. life cycle is isomorphic and biphasic type, also affected by biotic factors such as thallus age, phytohormones, microbiome, sporulation inhibitors and metabolomic. Due to that, types of farming can be implemented depending on the cultivation method and it is final biomass exploitation. Thus, this critical review analyzes the laminar Ulva species from the ecology and demonstrates that the seaweed biomass application, may make significant contributions to marine ecosystems, humans, aquaculture, and biotechnological innovation, indicating its importance in both environmental and socioeconomic contexts based on experiments across the world, time and critical thinking. This means that explaining the actual road and future roads of laminar Ulva into a multi-tool development from humankind welfare. With right management of resources and human empowerment, Ulva sp. products can be produced facing climate change and support different industries. However, responsible management of Ulva populations and farming is essential to prevent overgrowth, green floods, and maintain environmental equilibrium. [ABSTRACT FROM AUTHOR]

DNA sequences were obtained from 32 blade-forming Ulva specimens collected in 2018 and 2019 from four islands in the Galápagos Archipelago: Fernandina, Floreana, Isabela and San Cristóbal. The loci sequenced were nuclear encoded ITS and plastid encoded rbcL and tufA, all recognized as barcode markers for green algae. Four species were found, Ulva adhaerens, U. lactuca, U. ohnoi and U. tanneri, all of which have had their type specimens sequenced, ensuring the correct application of these names. Only one of these, U. lactuca, was reported historically from the archipelago. Ulva adhaerens was the species most commonly collected and widely distributed, occurring on all four islands. Previously known only from Japan and Korea, this is the first report of U. adhaerens from the southeast Pacific Ocean. Ulva ohnoi was collected on three islands, Isabela, Floreana, and San Cristóbal, and U. lactuca only on the last two. Ulva tanneri is a diminutive, 1–2 cm tall, high intertidal species that is easily overlooked, but likely far more common than the one specimen that was collected. This study of blade-forming Ulva species confirms that a concerted effort, using DNA sequencing, is needed to document the seaweed flora of the Galápagos Archipelago. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue of the journal Botanica Marina focused on the green seaweed Ulva. The collection of articles explores various aspects of Ulva, including its ecology, phylogeny, and practical applications in aquaculture. The articles cover topics such as taxonomy, cross-kingdom interactions with bacteria and fungi, and the cultivation of Ulva for sustainable alternatives to essential fatty acids. The special issue aims to advance our understanding of Ulva and its potential in sustainable aquaculture and ecological contexts. The collection is dedicated to the late Prof. Dr. Klaus Lüning, a renowned marine botanist who made significant contributions to the study of Ulva. The special issue is also supported by the EU-funded COST Action SeaWheat, which aims to integrate Ulva into various industries and daily life. [Extracted from the article]

Several studies have shown that endophytic fungal metabolites possess vital biological activities; nevertheless, there is a lack of knowledge regarding the medicinally important marine endophytic fungi associated with the seaweeds mainly found in the Bay of Bengal, Bangladesh. In this study, six endophytic fungi, belonging to five genera and four classes, were isolated from the well-known chlorophyte, Ulva sp. and were most closely related to Chaetomium globosum, Nigrospora magnoliae, Curvularia sp., Curvularia moringae, Aspergillus terreus and Collariella sp. This is the first report of these fungi as endophytes associated with Ulva sp. from the Bay of Bengal, Bangladesh. A preliminary biological evaluation of the ethyl acetate extract of each endophytic fungal crude extract was the prime objective of this research, e.g., antimicrobial assay, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and brine shrimp lethality bioassay. Evaluation of test results revealed that each fungal crude extract possessed one or more relevant biological activities. Preliminary chemical screening using TLC and NMR spectroscopic analysis revealed the presence of several secondary metabolites in the crude fungal extracts. These findings suggest that the marine endophytic fungus may be a valuable source for investigating potentially bioactive chemicals or leads for novel drug candidates. [ABSTRACT FROM AUTHOR]

Actinomycetota, associated with macroalgae, remains one of the least explored marine niches. The secondary metabolism of Actinomycetota, the primary microbial source of compounds relevant to biotechnology, continues to drive research into the distribution, dynamics, and metabolome of these microorganisms. In this study, we employed a combination of traditional cultivation and metagenomic analysis to investigate the diversity of Actinomycetota in two native macroalgae species from the Portuguese coast. We obtained and taxonomically identified a collection of 380 strains, which were distributed across 12 orders, 15 families, and 25 genera affiliated with the Actinomycetia class, with Streptomyces making up approximately 60% of the composition. Metagenomic results revealed the presence of Actinomycetota in both Chondrus crispus and Codium tomentosum datasets, with relative abundances of 11% and 2%, respectively. This approach identified 12 orders, 16 families, and 17 genera affiliated with Actinomycetota, with minimal overlap with the cultivation results. Acidimicrobiales emerged as the dominant actinobacterial order in both macroalgae, although no strain affiliated with this taxonomic group was successfully isolated. Our findings suggest that macroalgae represent a hotspot for Actinomycetota. The synergistic use of both culture‐dependent and independent approaches proved beneficial, enabling the identification and recovery of not only abundant but also rare taxonomic members. [ABSTRACT FROM AUTHOR]

The Western Antarctic Peninsula supports a diverse assemblage of > 100 described macroalgal species that contribute to the base of coastal food webs, but their contribution to local nearshore food webs is still uncertain across larger spatial scales. The analysis of biomarkers, specifically fatty acids and stable isotopes, offers a tool to clarify the trophic role of Antarctic macroalgae. The aim of this study was to describe the fatty acid profiles and stable isotope values of 31 algal species from three divisions (Chlorophyta—1, Ochrophyta—8, Rhodophyta—22) collected at the same sites for both biomarkers. Of these, 13 species had no previously published fatty acid profiles. Most species were rich in polyunsaturated fatty acids (PUFAs), suggesting they are highly nutritious and could be a resource of essential fatty acids for consumers. This was specifically noticeable in the overall low PUFA ratio (∑ω6/∑ω3 ratio), with low ratios being an indicator of high nutritional quality for consumers. Fatty acid profiles of macroalgae grouped strongly by phylogeny (at the levels of division, order, and family), while stable isotope groupings were more driven by the physiological properties of the species. Specifically, some closely related red algal species exhibited very different stable isotope values based on their carbon concentrating mechanisms, with highly 13C-depleted values in several Rhodophyta species. The fact that the two biomarker approaches created different groupings of Antarctic macroalgae collected at the same locations emphasizes that their combined application can be a powerful tool in Antarctic coastal food web studies. [ABSTRACT FROM AUTHOR]

Durvillaea incurvata is a brown macroalgae of ecological, social, and economic importance subjected to a drastic increase in harvesting pressure over the last decade in Chile. In this study, we performed an experimental transplantation of juveniles of D. incurvata, assessing the potential use as a restocking technique. Different types of restocking devices and attaching substrates were constructed. Differences in the D. incurvata re-attachment probability among the substrates and devices were not observed, and a high percentage of juvenile mortality was observed. However, reattached juveniles increased their length, holdfast diameter, and weight. The experiment revealed that juveniles of D. incurvata have a good capacity for reattachment and growth on artificial substrates after transplantation. This technique could be used for the species stock enhancement, although further studies are needed to optimize the process and increase the juvenile's reattachment. [ABSTRACT FROM AUTHOR]

The present investigation was carried out to evaluate the antimicrobial and antioxidant activities of four seaweed species gathered from the western coast of the northern Egyptian Red Sea using two different solvents: dichloromethane/methanol (1:1 v/v) and ethyl acetate. These species are Turbinaria ornata, Padina pavonica (Phaeophyta), Actinotrichia fragilis (Rhodophyta) and Ulva lactuca (Chlorophyta). The antimicrobial activity of the crude extracts was assessed in vitro against three microorganisms: Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus) and the yeast Candida albicans by the disc diffusion method. Both extracts of T. ornata and P. povonica showed a wide spectrum of antibacterial activity, however, the fungal entity Candida albicans was not inhibited in any way by any of the examined seaweed extracts. The efficacy of both solvents was discussed. The antioxidant activity was detected using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The highest activity was recorded in the dichloromethane/methanol extract of the brown seaweed T. ornata. On the other hand, the lowest activity was recorded in the ethyl acetate extract of the green seaweed Ulva lactuca. These findings revealed the potential of the Red Sea brown seaweeds as a promising candidate to act as antibacterial and antioxidant agent in medical applications. Further work is required to identify and separate the exact active compounds responsible for the biological activity. [ABSTRACT FROM AUTHOR]

Oomycetes are ubiquitous heterotrophs of considerable economic and ecological importance. Lately their diversity in marine environments has been shown to be greatly underappreciated and many lineages of intracellular holocarpic parasites, infecting micro- and macro-algae, remain to be fully described taxonomically. Among them, pathogens of marine red algae have been studied extensively as they infect important seaweed crops. Throughout the 20th century, most intracellular, holocarpic biotrophic oomycetes that infect red algae have been assigned to the genus Olpidiopsis Cornu. However, 18S rRNA sequencing of Olpidiopsis saprolegniae, the species considered the generitype for Olpidiopsis, suggests that this genus is not closely related to the marine pathogens and that the latter requires a nomenclatural update. Here, we compile and reanalyze all recently published 18S rRNA sequence data for marine holocarpic oomycetes, with a particular focus on holocarpic pathogens of red algae. Their taxonomy has been revised twice over the past four years, with suggestions to transfer them first into the genus Pontisma and then Sirolpidium, and into a monogeneric order, Pontismatales. We show however, that previously published topologies and the proposed taxa Pontisma, Sirolpidium, and Pontismatales are unsupported. We highlight that name changes that are unfounded and premature create confusion in interested parties, especially concerning pathogens of marine red algae that infect important seaweed crops. We thus propose that the names of these holocarpic biotrophic parasites of red algae are retained temporarily, until a supported topology is produced with more genetic markers to enable the circumscription of species and higher-level taxa. [ABSTRACT FROM AUTHOR]

Seven species of Callophyllis have been known off the Pacific coast of Russia; hovewer, molecular data have been obtained only for three species. In this study we re-examined the genus along the Russian Pacific coast using a comparative morphological study and molecular analyses based on rbcL and nrLSU. Five genetic species were identified on the Russian coast based on phylogenetics and species delimitation (ASAP and p-distance) analyses; while C. beringensis, C. papulosa and C. platyna were outscore of the analyses. The results of the molecular analyses uncovered one undescribed species, which we named C. selivanovae sp. nov. The divergence between this species and other species of the genus varied from 1.16% to 5.66%, while intraspecific divergence in the genus was in a range of 0.00%–0.22%. In phylogenetic trees C. selivanovae was recognized as sister to a diverse clade including C. thompsonii, C. beringensis, C. violacea, C. flabellulata and C. variegata from the Pacific coast of Canada. Callophyllis selivanovae from the southeastern coast of Kamchatka is morphologically close to C. beringensis, described from St. Paul Island (Bering Sea); the two species differ in features of branching, shape and size of the terminal branches. We propose a new name, C. perestenkoae sp. nov., for the algae previously listed in the Russian flora as 'C. flabellata'. Pacific specimens assigned to C. perestenkoae differ from C. flabellata from the type locality (Atlantic, France) in having irregular branching, thicker apical branches, and smaller cystocarps. We also filled in the gaps in the description of C. radula for which procarp and tetrasporangia are described herein for the first time. [ABSTRACT FROM AUTHOR]

The immune system acts as a defense mechanism against foreign antigens. Impairment of the immune system leads to the development of chronic diseases such as respiratory infections, cancer, cardiovascular diseases, and neurodegeneration. Macrophages, natural scavengers that are part of innate immunity, are known to directly participate in scavenging foreign antigens. The functional modulation of macrophages could be an effective treatment for pathogens. Seaweeds are marine macroalgae known to exhibit multiple bioactive properties. Thus, this study evaluated the immune-enhancing properties of marine brown algae extracts of Sargassum horneri (SH), Undaria pinnatifida (UP), and Sargassum fusiforme (SF) on murine macrophage cells. The results showed that all three algal extracts stimulated cell proliferation. SH and UP outshined SF in enhancing the expression levels of IL-1β, TNF-α, and IL-6 at almost all the concentrations tested as compared to SF which showed similar effects only at 200 or 400 μg/mL. A similar trend was seen in TNF-α, NO, and PGE2 production. Additionally, only SH and SF could enhance the mRNA expression levels of IL-12, and only SH upregulated the mRNA expression level of IL-10. The algal extracts also enhanced the phagocytosis activity of macrophages at 50–400 μg/mL for SH and 100–400 μg/mL for UP and SF. In conclusion, we found that these algal extracts could be considered immunomodulators that enhance the functional activity of macrophages. [ABSTRACT FROM AUTHOR]

Background: Solar radiation is primarily composed of ultraviolet radiation (UVR, 200 − 400 nm) and photosynthetically active radiation (PAR, 400 − 700 nm). Ultraviolet-B (UVB) radiation accounts for only a small proportion of sunlight, and it is the primary cause of plant photodamage. The use of chlorofluorocarbons (CFCs) as refrigerants caused serious ozone depletion in the 1980s, and this had led to an increase in UVB. Although CFC emissions have significantly decreased in recent years, UVB radiation still remains at a high intensity. UVB radiation increase is an important factor that influences plant physiological processes. Ulva prolifera, a type of macroalga found in the intertidal zone, is intermittently exposed to UVB. Alternative oxidase (AOX) plays an important role in plants under stresses. This research examines the changes in AOX activity and the relationships among AOX, photosynthesis, and reactive oxygen species (ROS) homeostasis in U. prolifera under changes in UVB and photosynthetically active radiation (PAR). Results: UVB was the main component of solar radiation impacting the typical intertidal green macroalgae U. prolifera. AOX was found to be important during the process of photosynthesis optimization of U. prolifera due to a synergistic effect with non-photochemical quenching (NPQ) under UVB radiation. AOX and glycolate oxidase (GO) worked together to achieve NADPH homeostasis to achieve photosynthesis optimization under changes in PAR + UVB. The synergism of AOX with superoxide dismutase (SOD) and catalase (CAT) was important during the process of ROS homeostasis under PAR + UVB. Conclusions: AOX plays an important role in the process of photosynthesis optimization and ROS homeostasis in U. prolifera under UVB radiation. This study provides further insights into the response of intertidal macroalgae to solar light changes. [ABSTRACT FROM AUTHOR]

Given sea ice's importance in global climate regulation, fully understanding the role of natural temperature and atmospheric patterns like the Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) in its variability is critical. While instrumental AMO and reliable AO records are available since the mid‐1800s and 1958, respectively, satellite sea‐ice concentration data sets start only in 1979, limiting the shared timespan to study their interplay. Growth increments of the coralline algae, Clathromorphum compactum, can provide sea‐ice proxy information for years prior to 1979. We present a seasonal 210‐year algal record from Lancaster Sound in the Canadian Arctic Archipelago capturing low frequency AMO/NAO variability and high frequency interannual AO/NAO prior to 2000. We suggest that sea‐ice variability here is strongly coupled to these large‐scale climate processes, and that sea‐ice cover was greater and the AO more negative in the early and late 19th century compared to the 20th. Plain Language Summary: Arctic sea‐ice variability is dually related to air/ocean temperatures and dynamic forces (wind patterns and ocean currents). While long‐term basin‐averaged temperature trends (i.e., Atlantic Multidecadal Oscillation) tend to influence variability over decades, cyclical wind patterns (e.g., Arctic Oscillation), may instead influence it seasonally and interannually. When the Atlantic Multidecadal and/or Arctic Oscillation (AMO/AO) are in a positive phase, warmer air and winds tend to export sea‐ice out of the Arctic, and vice‐versa during negative phases. Unfortunately, the span of the satellite sea‐ice cover record is too short to study long‐term sea‐ice variability driven by these patterns. Therefore, proxy records are required to fill this gap. The tree‐ring‐like growth bands of an Arctic coralline red algae have produced multi‐centennial proxy sea‐ice cover records. We present a 210‐year algal sea‐ice proxy record, showing a relationship with instrumental AMO (1861–present) and AO records (1958–2000). It also suggests that the AO was more negative and sea‐ice cover was greater during the 19th century in comparison to the 20th century. Due to sea‐ice's role in global climate at different timescales, this record can be utilized to tune climate models or constrain the relative influence of internal forcing on sea‐ice behavior. Key Points: Annual algal growth increment widths (sea ice cover proxy) correlate most strongly with summer Arctic Oscillation (AO) trendsAbrupt width increases in the early 1800s and 1920s capture sea‐ice cover decreases in phase with or slightly lagging behind +AMO phasesThe algal proxy record from Lancaster Sound captures +AO‐related sea‐ice export into the Canadian Arctic Archipelago [ABSTRACT FROM AUTHOR]

Marine environmental monitoring is essential to ensure that heavy-metal (HM) concentrations remain within safe limits. Most seawater analyses currently consider sediment or water samples, but this approach does not apply to rocky substrates, where water samples can only indicate immediate contamination. We used two common Mediterranean algae species, Cystoseira compressa and Ericaria mediterranea, as bioindicators living in the intertidal zone on rocky substrates along the seacoast. HM concentrations were assessed over a one-year period in the perennial base crust and in the seasonal frond, considering marine sites characterised by different contamination risks. Both algae showed that HMs accumulate mainly in the perennial base rather than in the seasonal frond. Furthermore, the algae species always showed a different order of bioaccumulation factors: Cd > Ni > Pb > Cr > Cu > Mn > Zn for the frond and Pb > Cr > Ni > Cd > Mn > Cu > Zn for the base. Our study shows that C. compressa and E. mediterranea accumulate HM consistently with the types of sites analysed and differentially with respect to the part of the thallus. These results demonstrate that these algae can be effectively used as reliable bioindicators to assess the presence of HM in marine environments with rocky substrates, providing both short- and long-term monitoring. [ABSTRACT FROM AUTHOR]

Over the last 2 decades, routine collections in the Hawaiian Archipelago have expanded to mesophotic reefs, leading to the discovery of a new red algal genus and species, here described as Anunuuluaehu liula gen. et sp. nov. This study provides a detailed genus and species description and characterizes chloroplast and mitochondrial organellar genomes. The new genus, Anunuuluaehu, shares many characteristics with the family Phyllophoraceae and shows close similarities to Archestennogramma and Stenogramma, including habit morphology, nemathecia forming proliferations at the outer cortex with terminal chains of tetrasporangia, and carposporophytes with multi‐layered pericarps. The single species in this genus exhibits distinctive features within the Phyllophoraceae: the presence of single‐layer construction of large medullary cells and the development of long, tubular gonimoblastic filaments. Multi‐gene phylogenetic analyses confirmed it as a unique, monophyletic lineage within the family. Cis‐splicing genes, interrupted by intron‐encoded proteins within group II introns, are present in both the chloroplast and mitochondrial genomes of A. liula. Notably, a specific region of the coxI group II intron exhibits similarity to fungal introns. Anunuuluaehu liula is presumed to be endemic to the Hawaiian Archipelago and thus far is known to live solely at mesophotic depths from Hōlanikū to Kaho'olawe ranging from 54 to 201 m, which is the deepest collection record of any representative in the family. Overall, this study enhances our understanding of the genomic and taxonomic complexities of red algae in mesophotic habitats, emphasizing the significance of continued research in this area to uncover further insights into evolutionary processes and biogeographic patterns. [ABSTRACT FROM AUTHOR]