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Interest in farming kelps has grown beyond using kelp for food, feed or biofuels. There is considerable interest in generating biomass from seaweed for use in bioplastics and other products that would substitute for petroleum-derived products. For these uses to be viable, large amounts of biomass are needed. Very large kelp farms can be expensive to build and maintain, leading to the need to optimize the biomass per unit area. Although close spacing of growlines can lead to poor growth, a viable approach may be to grow two species of kelps together: one that hangs down and one that is buoyant, growing up. This system would increase the spacing in three dimensions. In Alaska, Saccharina latissima is commonly grown hanging down from longlines. One of the buoyant Alaskan kelps is Nereocystis luetkeana. Because there are commercial uses for wild-harvested Nereocystis in Alaska, we undertook a preliminary trial in Kodiak, Alaska, that grew both Saccharina and Nereocystis in the same longline array. Closely spaced lines were seeded the first week of February 2023 and set at 3 m below the surface. The arrays were harvested in late June 2023. Total yields were greatest on the combined arrays, followed by the Nereocystis only and Saccharina only arrays. Despite having 45% fewer grow-lines, the total yield of the Nereocystis on the combined arrays was statistically similar to the Nereocystis only arrays. These results may have significance for large scale macroalgal production. [ABSTRACT FROM AUTHOR]

Summary: The impact of the addition of seaweed to yoghurt was evaluated on its physicochemical, functional and sensory properties. Two different species of brown macroalgae, Saccharina latissima (blanched or not) and Alaria esculenta, were added in four different concentrations (0.25%, 0.50%, 0.75% and 1%) and in two different forms (flakes and powder). The titratable acidity of all yoghurt samples formulated with blanched Saccharina was similar to the control. However, formulations with blanched Saccharina exhibited higher syneresis than the control. Most yoghurt samples containing Alaria at higher concentrations exhibited a lower firmness than the control. Seaweed addition had a significant impact on the colour of yoghurt samples. Quantitative descriptive analysis and hedonic evaluation performed by a trained panel showed that changes in physicochemical properties influenced the organoleptic characteristics of yoghurt samples. Yoghurt samples formulated with 0.25% S. latissima and 0.50% A. esculenta in flakes were selected as the most promising formulations. [ABSTRACT FROM AUTHOR]

Dynamic models of sugar kelp (Saccharina latissima) growth are used to estimate the production potential of seaweed aquaculture in many regions around the world. These models do not currently account for the existence of S. latissima ecotypes that are adapted to regional environmental conditions, particularly temperature. We tested the hypothesis that recalibrating the temperature parameters of a dynamic energy budget model using literature data for S. latissima from regions with a similar climate to the region of interest would result in more accurate predictions than using a general species‐wide temperature response curve. Calibrating the model using data from warm regions significantly improved model accuracy for kelp cultivation at the southern end of the species range (Rhode Island, USA) in cases where the original parameters underestimated growth but resulted in drastic overestimates when heavy frond erosion occurred. In Trømso, Norway, a cold parameterization produced extremely accurate predictions: the model predicted a final frond length of 88.2 cm, compared with the observed length of 87.5 (±4.70) cm. Our results demonstrate that recalibrating temperature response curves allows one model to be applied to kelp aquaculture in different regions, an important step toward the prediction of S. latissima productivity over large areas. [ABSTRACT FROM AUTHOR]

Recent interest in scaling commercial kelp industries in Western cultures is juxtaposed by the apparent challenges in achieving more consistent and predictable yields. As such, site-level factors are a dominant and recurring conversation amongst stakeholders. The availability of seawater nitrogen (nitrate, ammonium, total N) can be highly variable across space and time and is often one of the top concerns for site selection and permitting. This study questions the relative importance of nitrogen availability on the yield of Saccharina latissima (sugar kelp) across five commercial farms on the U.S. East and West Coasts over two seasons, highlighting the relative influence of other interacting factors (i.e., farm design). We hypothesized that nitrate would strongly correlate with the harvested yield. Our results show significant spatial and annual variability in the kelp yield and ambient nutrients across and within farms, but with weak covariance. Standard linear regression suggests that seawater nitrogen is a poor explanatory factor for kelp yield, explaining 11.0% of the variation around the mean compared to the line spacing (explaining 26.1%) and the interaction between the total N and the line spacing (explaining 50.0%). Quartile regression, however, suggests that total N alone, is the strongest predictor of a lower threshold in terms of the yield (0.10 quartile, r2 = 0.431) relative to the median (0.50 quartile, r2 0.081). As such, seawater nitrogen may be a more useful metric in predicting baseline kelp yields rather than realized yields, and production above that baseline is likely more dependent on other factors that may or may not interact with seawater nitrogen. [ABSTRACT FROM AUTHOR]

Saccharina japonica, a significant brown macroalga in the Pacific Ocean, serves as a food source and industrial material. In aquaculture, collecting mature sporophytes for seedling production is essential but challenging due to environmental changes. In this study, transcriptomic analysis of vegetative and sorus tissues was done to identify differentially expressed genes (DEGs) and enhance our understanding of sorus formation regulation in S. japonica. KEGG pathway and Gene Otology (GO) analysis revealed that upregulated DEGs were involved in folate biosynthesis, riboflavin metabolism, and amino acid biosynthesis. In addition, the upregulation of genes associated with cell wall remodeling, such as mannuronan C-5-epimerases, vanadium-dependent haloperoxidases, and NADPH oxidase, was observed in sorus parts. Meanwhile, downregulated DEGs in sorus portions included genes related to chloroplast function. These findings will help us understand the regulatory mechanisms behind sorus formation in S. japonica and extracellular matrix remodeling in brown algae. [ABSTRACT FROM AUTHOR]

DNA cytosine methylation is an important epigenetic mechanism in genomic DNA. In most land plants, it is absent in the chloroplast DNA. We detected methylation in the chloroplast DNA of the kelp Saccharina latissima, a non‐model macroalgal species of high ecological and economic importance. Since the functional role of the chloroplast methylome is yet largely unknown, this fundamental research assessed the chloroplast DNA cytosine methylation in wild and laboratory raised kelp from different climatic origins (High‐Arctic at 79° N, and temperate at 54° N), and in laboratory samples from these origins raised at different temperatures (5, 10 and 15°C). Results suggest genome‐wide differences in methylated sites and methylation level between the origins, while rearing temperature had only weak effects on the chloroplast methylome. Our findings point at the importance of matching conditions to origin in restoration and cultivation processes to be valid even on plastid level. [ABSTRACT FROM AUTHOR]

Brown algae are gaining traction as biorefinery feedstocks due to their advantages such as rapid growth and carbon dioxide sequestration. Saccharina japonica has high potential due to its high carbohydrate content, especially mannitol (26.7%). In this study, a biorefinery process for S. japonica was designed, with focusing on sugar conversion and bioconversion into lactic acid, a valuable platform chemical utilized in various industries. The existing sugar conversion process of S. japonica has been investigated by focusing on enzymatic or acid‐catalyzed hydrolysis, but not hot water extraction although mannitol can be easily recovered using water. The effect of temperature (60–120°C) on the mannitol yield from S. japonica was investigated, and a mannitol yield of 208 g/kg biomass was achieved at the optimal temperature of 100°C (about 78% of the theoretical maximum yield). This study emphasizes that this simple process has considerable potential for application as over 80% of the fermentable carbohydrates in S. japonica were mannitol. Then, S. japonica extract was applied to lactic acid production. First, lactic acid production of four bacterial strains was tested in a mannitol medium, and Lacticaseibacillus rhamnosus was selected as the superior producer, showing 1.93 to 2.92 times better lactic acid titer than others. Next, the optimal feeding concentration of mannitol was determined to be 20 g/L, which was all consumed by L. rhamnosus. Finally, S. japonica extract was applied to lactic acid production by L. rhamnosus, and the results showed similar fermentation profiles with the control medium: lactic acid production, 18.81 g/L (control: 18.97 g/L); lactic acid conversion, 95.1% (control: 95.9%); cell growth (OD600 nm), 8.9 (control: 7.4). The lactic acid yield in the designed biorefinery process was estimated to be 195.6 g/kg biomass, thus S. japonica has high potential as a biorefinery feedstock to produce valuable bioproducts, including lactic acid. [ABSTRACT FROM AUTHOR]

It is important to eliminate the fishy odor and improve the aroma quality of seafood. In this study, the Saccharina japonica (S. japonica) seedling, which is a new food material, was investigated for the effects of fermentation with Saccharomyces cerevisiae (S. cerevisiae) through sensory evaluation, GC–MS, and odor activity value (OAV) analysis. GC–MS analysis revealed the presence of 43 volatile compounds in the unfermented S. japonica seedling, with 1-octen-3-ol, hexanal, and trans-2,4-decadienal identified as the main contributors to its fishy odor. After fermentation with S. cerevisiae, 26 volatile compounds were identified in the S. japonica seedling. Notably, the major malodorous fish compounds, including 1-octen-3-ol, hexanal and trans-2,4-decadienal, were no longer present. The results indicate that fermentation with S. cerevisiae is an effective method for removing fishy malodor compounds and enhancing the volatile components with fruity, sweet, green, and floral notes in the Saccharina japonica seedling. This process facilitates the elimination of fishy malodor and enhance the fruity, sweet, green, and floral notes of S. japonica seeding and other seaweeds. [ABSTRACT FROM AUTHOR]

Wild-type sporophytes of Saccharina japonica have been recurrently observed on the infrastructures of kelp farming rafts in China's northern production region (Liaoning and Shandong provinces). However, there are few detailed reports delineating their origin, genetic attributes and affiliations with farmed populations. Using microsatellite molecular analyses, we furnish a comparative analysis of the populations sampled from these rafts at one of the historical kelp farming regions Rongcheng city (Shandong province), both before and after the "2021–2022 kelp farming disaster", in conjunction with two field populations from nearby intertidal zones where natural populations prevail. The results show that the wild kelp populations on the kelp farming rafts in 2023 had originated from the wild populations dwelling in intertidal zones several kilometers away, rather than from the artificially cultivated kelp cultivars. [ABSTRACT FROM AUTHOR]

Brining and dry salting are traditional preservation techniques used to extend the shelf life of foods including seaweeds. In this study, brining (40% NaCl solution weight/volume) and dry salting (30% weight/weight) processes were applied to fresh kelp to achieve a target water activity of less than 0.77, and the effect of salting treatment on consumer acceptance was assessed. The processed samples were stored at 4 °C for 2 weeks until the sensory analysis. Processed kelp samples were used as the primary ingredient in a salad with shredded carrots and sesame dressing. Three salad samples (salad with fresh kelp (control), brined, or dry salted sugar kelp) were presented to the panelists to assess the liking of sensory attributes including salt intensity, color, aroma, flavor, texture, and overall liking. Significant differences in the liking of flavor and texture were observed, with consumers rating both treatments made with salted seaweed higher than a salad made from fresh seaweed. Panelists identified the availability and lack of information regarding nutritional benefits as barriers to their seaweed consumption. These results indicate that in addition to extending shelf life, the preservation of kelp by salting may increase consumer acceptability. [ABSTRACT FROM AUTHOR]

The brown macroalga Saccharina japonica (Laminariales, Phaeophyta) is the most productive cultured seaweed in the world. In order to improve the biosafety of transgenic kelp, it is necessary to develop endogenous constitutive promoters, replacing those of virus origin. In this study, the housekeeping actin gene from S. japonica (SjACT) was found to contain three exons and two introns, representing a unique actin gene structure pattern in brown algae. Additionally, the 5′ upstream region was obtained using genome walking, and fused to the reporter gene lacZ or EGFP to construct promoter-detective vectors. Using an established genetic transformation system, kelps in different life-cycle stages were transformed. The detection results showed that, in the diploid sporophyte stage, the transient expression from the lacZ gene could be observed in the frond, stipe, or holdfast of kelps, indicating a manner of being non-tissue-specific. And, in the haploid gametophyte stage of S. japonica, the fluorescence of the expressed EGFP were detected in vivo in gametophyte cells of both genders. These results indicate that the promoter of the SjACT gene (pSjACT) functions in a constitutive manner and is expected to be a key endogenous element in the genetic manipulation of kelps. [ABSTRACT FROM AUTHOR]

In mid-November 2021, there were large areas of white rot disease on cultivated Saccharina japonica in Rongcheng City, China, and diseases were undetected on Sargassum horneri and Porphyra yezoensis. The disturbance direction of bacterial community in the phycosphere after disease outbreak and the relationship with seawater nutrients remain unclear. Here, in situ studies of bacterial community in the non-diseased and diseased areas (Shawo and Dongchu islands) and seawater nutrient levels were carried out. 16S rRNA sequencing showed that the bacterial richness of the studied seaweeds increased in the diseased area. Only in S. japonica, Algitalea outcompeted abundant primary bacteria with probiotic relationships to the host of the non-diseased area, and dominated in the diseased area (17.6% of the total abundance). Nitrogen and phosphorus levels in seawater were 57.8% and 19.6% higher in the non-diseased area than those in the diseased area, respectively, and were strongly correlated with the phycosphere bacteria at the family level of S. japonica. There was no difference in potential pathogenicity between the two areas, while positive signal communications decreased, and nitrogen cycle, chemoheterotrophy, and cellulolysis increased in the diseased area compared to the non-diseased area. Overall, white rot disease caused a structural disturbance in phycosphere bacterial community of S. japonica that related to seawater nutrient levels. Enriched degraders and altered bacterial community functions may exacerbate the disease. This evaluation will provide information for white rot disease management to prevent and mitigate the occurrence of S. japonica outbreaks. [ABSTRACT FROM AUTHOR]

Macroalgae are considered healthy food ingredients due to their content in numerous bioactive compounds, and the traditional use of whole macroalgae in Asian cuisine suggests a contribution to longevity. Although much information is available about the bioactivity of pure algal compounds, such as different polyphenols and polysaccharides, documentation of potential effects of whole macroalgae as part of Western diets is limited. Lifestyle- and age-related diseases, which have a high impact on population health, are closely connected to underlying chronic inflammation. Therefore, we have studied crude extracts of green (Ulva fenestrata) and brown (Saccharina latissima) macroalgae, as two of the most promising food macroalgae in the Nordic countries for their effect on inflammation in vitro. Human macrophage-like reporter THP-1 cells were treated with macroalgae extracts and stimulated with lipopolysaccharide (LPS) to induce inflammatory signalling. Effects of the macroalgae extracts were assessed on transcription factor activity of NF-κB and IRF as well as secretion and/or expression of the cytokines TNF-α and IFN-β and chemokines IL-8 and CXCL10. The crude macroalgae extracts were further separated into polyphenol-enriched and polysaccharide-enriched fractions, which were also tested for their effect on transcription factor activity. Interestingly, we observed a selective activation of NF-κB, when cells were treated with macroalgae extracts. On the other hand, pretreatment with macroalgae extracts selectively repressed IRF activation when inflammatory signaling was subsequently induced by LPS. This effect was consistent for both tested species as well as for polyphenol- and polysaccharide-enriched fractions, of which the latter had more pronounced effects. Overall, this is the first indication of how macroalgae could modulate inflammatory signaling by selective activation and subsequent repression of different pathways. Further in vitro and in vivo studies of this mechanism would be needed to understand how macroalgae consumption could influence the prevention of noncommunicable, lifestyle- and age-related diseases that are highly related to unbalanced inflammatory processes. [ABSTRACT FROM AUTHOR]

Brown algae are multicellular organisms that have evolved independently from plants and animals. Knowledge of the mechanisms involved in their embryogenesis is available only for the Fucus, Dictyota, and Ectocarpus, which are brown algae belonging to three different orders. Here, we address the control of cell growth and cell division orientation in the embryo of Saccharina latissima, a brown alga belonging to the order Laminariales, which grows as a stack of cells through transverse cell divisions until growth is initiated along the perpendicular axis. Using laser ablation, we show that apical and basal cells have different functions in the embryogenesis of this alga, with the apical cell being involved mainly in growth and basal cells controlling the orientation of cell division by inhibiting longitudinal cell division and thereby the widening of the embryo. These functions were observed in the very early development before the embryo reached the 8-cell stage. In addition, the growth of the apical and basal regions appears to be cell-autonomous, because there was no compensation for the loss of a significant part of the embryo upon laser ablation, resulting in smaller and less elongated embryos compared with intact embryos. In contrast, the orientation of cell division in the apical region of the embryo appears to be controlled by the basal cell only, which suggests a polarised, non-cell-autonomous mechanism. Altogether, our results shed light on the early mechanisms of growth rate and growth orientation at the onset of the embryogenesis of Saccharina, in which non-cell-specific cell-autonomous and cell-specific non-cell-autonomous processes are involved. This complex control differs from the mechanisms described in the other brown algal embryos, in which the establishment of embryo polarity depends on environmental cues. [ABSTRACT FROM AUTHOR]

In this study, we conducted sea urchin removal (SUR) experiments at two sites along Hokkaido's southwestern and northwestern coasts in the Sea of Japan and one site along the northeast coast in the Sea of Okhotsk, to elucidate the biomass balance between macroalgae and sea urchins at different urchin barren sites. The experiments resulted in the restoration of macroalgal biomass at all sites and an increase in macroalgal diversity, indicating that it was the impact of high grazing pressure reducing the macroalgae, regardless of the particular experimental site. Notably, the recovery of the macroalgal biomass was characterized by increased kelp biomass, including Saccharina japonica var. religiosa and S. japonica var. ochotensis. In addition, negative correlations were observed between macroalgal biomass and sea urchin density. The lowest sea urchin density inducing an increase of macroalgal biomass was approximately the same in the reproductive growth phase (0.1 kg m−2) and in the vegetative growth phase (0.15 kg m−2) of Saccharina spp., the dominant kelps, regardless of the experimental site. These values can be helpful indicators for managing sea urchin density in order to restore macroalgae. In contrast, the maximum sea urchin density inducing the lowest macroalgal biomass varied markedly depending on the study site, indicating that different levels of kelp productivity are influenced by oceanographic conditions. Moreover, a strong positive correlation was observed between macroalgal biomass and sea urchins' gonadosomatic index (GSI). Based on this correlation, macroalgal biomass supporting sea urchins with commercial value (GSI ≥ 15%) was estimated to be 1.6 kg m−2. This sea urchin density value is also a helpful indicator for managing macroalgal biomass and commercially valuable sea urchins. Moreover, this value will depend on the influence of the oceanographic environment of the site, particularly the nutrient conditions, on macroalgal productivity. In addition, we have also discussed how macroalgae and sea urchins can best coexist at the experimental sites. Sea urchin removal (SUR) restored macroalgal biomass and diversity. Recovery of macroalgal biomass by SUR was characterized by kelps. Kelp biomass required to support the commercial sea urchin production was estimated. [ABSTRACT FROM AUTHOR]

Aquaculture farms cultivating Saccharina japonica are highly active in Wando, Korea, and Rongcheng, China. However, the yield of S. japonica significantly declined in the Rongcheng region in 2022 compared to previous records, whereas that in Wando remained at a normal level, presumably due to the presence of a pathogenic microbiome. We used environmental DNA (eDNA) metagenomic analysis to compare the microbial compositions of seawater from aquaculture farms in Wando and Rongcheng. Seawater samples were collected from one Korean site in Wando (WA) and two Chinese sites in Ailian Bay (AB) and Lidao Bay (LB). Metagenomic analysis focusing on the microbial 16S rRNA identified 38 phyla and 58 families of microbiomes in all regions. Potentially pathogenic bacterial groups associated with S. japonica in AB and LB were more abundant than in WA, suggesting their potential influence on mortality and the decline in the harvest yield of S. japonica. The microbial composition of WA was distinguished from those of the other two sites, which clustered together with higher similarity. Since the S. japonica aquaculture industry is important for both countries, this comparative eDNA monitoring is a valuable initiation towards the next step of problem-solving practices in coastal management in these two aquaculture systems. [ABSTRACT FROM AUTHOR]

It was reported that the consumption of Saccharina japonica (SJ) lowers blood pressure (BP) in hypertensive rats. Hypertension is related to gut microbiota, and hypertensive patients develop dysbiosis. It was reported that the intake of dietary fiber and polysaccharides contained in SJ changes gut microbiota and increases short-chain fatty acids (SCFAs). The present study examined the effect of BP lowering by SJ in spontaneously hypertensive rats (SHRs) and observed changes in gut microbiota composition and SCFAs concentration. Male SHRs and Wistar Kyoto rats (WKYs) were fed a diet containing 5% SJ or a control diet for six weeks. We measured systolic BP (SBP) weekly, as well as mean arterial BP (MAP), the 16S rRNA gene, and SCFAs in the cecal contents at the end of the period. As a result, the intake of SJ significantly decreased SBP and MAP in SHRs. As well, it significantly changed the microbial diversity by altering the gut microbiota composition. Particularly, it increased the abundance of Bacteroides acidifaciens, which may be associated with the antihypertensive effect of SJ. Thus, SJ intake suppressed the increase in BP and altered the gut microbiota composition, although it did not significantly change the SCFAs concentration in the cecal contents. [ABSTRACT FROM AUTHOR]

Post-harvest changes in the quality of cut and whole S. latissima upon 23 days storage with or without acidification at different temperatures were studied by bacterial counts, amino acids composition, and 1H-NMR profiling of extracted metabolites. Lowering the temperature inhibited bacterial growth, and seaweed stored 10 days at 4°C had the same bacterial counts as seaweed stored 2 days at room temperature. Cutting reduced the bacterial degradation of mannitol, free amino acids, and other low molecular components but made proteins and carbohydrates more available for enzymatic hydrolysis. Acidification hindered microbial growth and reduced degradation of amino acids and other components. [ABSTRACT FROM AUTHOR]

Background and Aims Changes in kelp abundances on regional scales have been highly variable over the past half-century owing to strong effects of local and regional drivers. Here, we assess patterns and dominant environmental variables causing spatial and interspecific variability in kelp persistence and resilience to change in Nova Scotia over the past 40 years. Methods We conducted a survey of macrophyte abundance at 251 sites spanning the Atlantic coast of Nova Scotia from 2019 to 2022. We use this dataset to describe spatial variability in kelp species abundances, compare species occurrences to surveys conducted in 1982 and assess changes in kelp abundance over the past 22 years. We then relate spatial and temporal patterns in abundance and resilience to environmental metrics. Key Results Our results show losses of sea urchins and the cold-tolerant kelp species Alaria esculenta , Saccorhiza dermatodea and Agarum clathratum in Nova Scotia since 1982 in favour of the more warm-tolerant kelps Saccharina latissima and Laminaria digitata. Kelp abundances have increased slightly since 2000, and Saccharina latissima and L. digitata are widely abundant in the region today. The highest kelp cover occurs on wave-exposed shores and at sites where temperatures have remained below thresholds for growth (21 °C) and mortality (23 °C). Moreover, kelp has recovered from turf dominance following losses at some sites during a warm period from 2010 to 2012. Conclusions Our results indicate that dramatic changes in kelp community composition and a loss of sea urchin herbivory as a dominant driver of change in the system have occurred in Nova Scotia over the past 40 years. However, a broad-scale shift to turf-dominance has not occurred, as predicted, and our results suggest that resilience and persistence are still a feature of kelp forests in the region despite rapid warming over the past several decades. [ABSTRACT FROM AUTHOR]

Background The sugar kelp Saccharina latissima is a Laminariales species widely distributed in the Northern Hemisphere. Its physiology and ecology have been studied since the 1960s, given its ecological relevance on western temperate coasts. However, research interest has been rising recently, driven mainly by reports of negative impacts of anthropogenically induced environmental change and by the increased commercial interest in cultivating the species, with several industrial applications for the resulting biomass. Scope We used a variety of sources published between 2009 to May 2023 (but including some earlier literature where required), to provide a comprehensive review of the ecology, physiology, biochemical and molecular biology of S. latissima. In so doing we aimed to better understand the species' response to stressors in natural communities, but also inform the sustainable cultivation of the species. Conclusion Due to its wide distribution, S. latissima has developed a variety of physiological and biochemical mechanisms to adjust to environmental changes, including adjustments in photosynthetic parameters, modulation of osmolytes and antioxidants, reprogramming of gene expression and epigenetic modifications, among others summarized in this review. This is particularly important because massive changes in the abundance and distribution of S. latissima have already been observed. Namely, presence and abundance of S. latissima has significantly decreased at the rear edges on both sides of the Atlantic, and increased in abundance at the polar regions. These changes were mainly caused by climate change and will therefore be increasingly evident in the future. Recent developments in genomics, transcriptomics and epigenomics have clarified the existence of genetic differentiation along its distributional range with implications in the fitness at some locations. The complex biotic and abiotic interactions unraveled here demonstrated the cascading effects the disappearance of a kelp forest can have in a marine ecosystem. We show how S. latissima is an excellent model to study acclimation and adaptation to environmental variability and how to predict future distribution and persistence under climate change. [ABSTRACT FROM AUTHOR]

The healthy "superfood" sector is currently quickly developing in Europe, and grocery stores are increasingly stocking macroalgae food supplements. Due to its high amount of protein, fiber, and minerals, numerous studies have demonstrated that seaweed has a significant potential for usage as a functional ingredient in the food sector. The aim of the current study was to evaluate the rheological (ICC 173 standard method) and chemical potentials of using Saccharina latissima flour in the bread sector. The calcium level of S. latissima flour was found to be 8236 mg/kg, the magnesium level was 6041 mg/kg, the K concentration was 62,088 mg/kg, the iron content was 35.23 mg/kg, the P content was 2263 mg/kg, and the I content was 12,530 mg/kg, significantly higher values than those of wheat flour. The antioxidant properties of the algae powder used were highlighted by the analysis of the total polyphenol content and its antioxidant activity (DPPH method). Four bread samples, which were compared with the control sample entirely made of wheat flour in order to evaluate their potential, were made, using a replacement degree from 1.5% to 6% of S. latissima. Rheological analyses were completed using the ICC 173 standard method, as well as sensorial analysis, where a panel of assessors' evaluations compared the sensory properties of samples with 1.5–6% of S. latissima flour to a control sample manufactured with flour type 650. It was concluded that sample A1 (1.5% algae flour) has sensorial properties similar to those of the control sample, and, for the other samples, the properties began to degrade with the increase in the amount of algae flour. Textural analyses performed during 96 h of storage show that the firmness and gumminess increase with the addition of algae flour and over time. The conclusions indicated that samples comprising 4.5% and 6% of S. latissima are unsatisfactory from a rheological and sensory perspective, while samples having 1.5% and 3% of S. latissima can be viewed as sources of fiber and minerals. [ABSTRACT FROM AUTHOR]

Kelp forest declines have been linked to warming ocean temperatures worldwide. Ocean warming rarely occurs in isolation, so multiple stressor studies are necessary to understand the physiological responses of kelp to climate change. The canopy-forming bull kelp, Nereocystis luetkeana, is going locally extinct in areas of the Salish Sea that are seasonally warm and nutrient poor, while the understory kelp, Saccharina latissima, persists at those sites. Further, nitrogen availability can alter physiological responses of kelps to temperature stress, including alleviating warming stress. We compared the physiological responses of kelp sporophytes to high temperature stress and nitrogen limitation between two populations of N. luetkeana with different environmental histories (warm and nutrient poor vs. cold and nutrient rich) and between two species, N. luetkeana and S. latissima. Using laboratory mesocosms, we tested the interactive effects of short term (8-9 day) exposure of kelp blades to different temperatures: low (9, 13°C), moderate (15, 16°C), and warm (21°C) at two different nitrogen concentrations: low (1-3 μM) vs. high (>10 μM). We examined a wide array of physiological responses: blade growth, photosynthesis, respiration, photosynthetic yield, nutrient uptake, and tissue C:N. Both kelp species responded negatively to elevated temperatures, but not to low nitrogen levels. Blades of both species showed signs of metabolic stress and reduced growth in the warmest temperature treatment (21°C), at both high and low nitrogen levels, suggesting that N. luetkeana and S. latissima are susceptible to thermal stress over short time periods. Populations of N. luetkeana from warm, nutrient poor and cool, nutrient rich areas were equally susceptible to the effects of ocean warming. Our results suggest that nutrient additions may actually reduce kelp performance at supra-optimal temperatures, and a thorough understanding of kelp responses to coastal temperature and nutrient dynamics is needed to guide conservation and restoration actions. [ABSTRACT FROM AUTHOR]

Phaeoviruses (Phycodnaviridae) are large icosahedral viruses in the phylum Nucleocytoviricota with dsDNA genomes ranging from 160 to 560 kb, infecting multicellular brown algae (Phaeophyceae). The phaeoviral host range is broader than expected, not only infecting algae from the Ectocarpales but also from the Laminariales order. However, despite phaeoviral infections being reported globally, Norwegian kelp species have not been screened. A molecular analysis of cultured and wild samples of two economically important kelp species in Norway (Saccharina latissima and Laminaria hyperborea) revealed that phaeoviruses are recurrently present along the Norwegian coast. We found the viral prevalence in S. latissima to be significantly higher at the present time compared to four years ago. We also observed regional differences within older samples, in which infections were significantly lower in northern areas than in the south or the fjords. Moreover, up to three different viral sequences were found in the same algal individual, one of which does not belong to the Phaeovirus genus and has never been reported before. This master variant therefore represents a putative new member of an unclassified phycodnavirus genus. [ABSTRACT FROM AUTHOR]

The phenology of the alga-dwelling amphipod Ceinina japonica Stephensen, 1933 (Amphipoda: Eophliantidae) was studied at Rishiri Island, Hokkaido, Japan, from May 2016 to March 2017. Seasonal shifting between the host algal species was confirmed through observations at a coastal field site and a nearby aquaculture facility for kelp. Amphipods mainly occurred in the farmed biennial kelp Saccharina japonica var. ochotensis and wild algae Undaria pinnatifida, with Agarum clathratum, Costaria costata, Saccharina cichorioides, and Sargassum boreale as new host algal records. Amphipods occurred in sporophytes of U. pinnatifida at the field site from February to March and from May to July, but they were found in the kelp of S. j. var. ochotensis during the rest of the year, from August to the following January. Individuals of C. japonica infected sporophytes of the large brown alga Undaria pinnatifida from February to July, and C. japonica reproduced from July to September, a period during which the amphipods switch to a different host in July, the sporophytes of the saccharinan kelp S. j. var. ochotensis, where they stay until January. The amphipods then switched back to U. pinnatifida in January or February. Experimental evidence from a kelp-culturing facility also confirmed the timing of this host shift. The removal of U. pinnatifida from algal culture ropes in such facilities is suggested as a method to prevent amphipod damage, which is important for commercially farmed S. j. var. ochotensis. [ABSTRACT FROM AUTHOR]

Using low trophic marine resources such as sugar kelp (Saccharina latissimi) is of great interest to increase the circular food production in the ocean. Sugar kelp does, however, contain high levels of carbohydrates and iodine and does not have considerable levels of protein and lipids, which may make it less suitable as a feeding ingredient. A 10-week feeding trial was done to investigate the effect of graded dietary inclusion levels of fermented sugar kelp (FSK), on growth performance, digestibility, retention of nutrients, and mineral composition in postsmolt Atlantic salmon (Salmo salar L.). The experimental diets were made to simulate a standard grower feed for salmon postsmolts in SW with ∼63% plant-based ingredients vs ∼34% marine ingredients and increasing concentrations of FSK between 0% (control feed) and 4% of the diet. During the feeding trial, the weight gain and specific growth rate (SGR) decreased linearly with increasing dietary FSK levels, where the SGR was slightly reduced from 1.2% for the fish given the control feed to 1.1% in the fish given feeds containing 3% and 4% FSK. This resulted in a lower weight gain of up to 9% in the fish given 4% FSK compared to the control. Feed intake and feed conversion ratio were, however, similar in all diet groups, and FSK inclusion did not influence the digestibility of macronutrients or minerals, except for lipid. The reduced growth is likely related to a lower digestible energy level in the diets, and the retention of both lipids and energy was affected by FSK inclusion. Inclusion of FSK also influenced iodine availability and retention, as well as increasing iodine status in whole body and muscle in a dose-dependent manner until reaching a plateau, which corresponds to 124 mg I kg−1 WW (135 mg I kg−1 DW), at 3% FSK inclusion. [ABSTRACT FROM AUTHOR]

Alginates are heteropolysaccharides comprising β-D-mannuronate (M) and α-L-guluronate (G) units. Natural sources of alginate include brown algae and certain bacteria. Brown algal alginates possess a greater degree of sequence diversity than do those produced by bacteria, and this may be due to the presence of multiple mannuronan C5-epimerase (MC5E) isozymes in brown algae, although only three have been enzymatically studied to date. In this study, a novel MC5E candidate protein, CoC5-1, from the brown alga Cladosiphon okamuranus, for which no enzymatic function has been previously determined, was expressed as a glycosylated protein in insect cells. The action of recombinant CoC5-1 on polymannuronate (polyM) increased the amount of gel formed in the presence of Ca2+, indicating that CoC5-1 possesses MC5E activity. The optimum temperature, pH, and NaCl concentration were 40 °C, pH 8.0, and 100 mM, respectively. The thermal stability of CoC5-1 was higher than that of the Saccharina japonica MC5E SjC5-VI. CoC5-1 remained active after incubation at 50 °C for 1 h, whereas SjC5-VI was completely inactivated. 1H-nuclear magnetic resonance (NMR) analysis revealed that the M:G ratio of the polyM substrate was altered from 9.0 to 2.1 by CoC5-1. This is the first report of MC5E enzymatic activity in brown algae of the family Chordariaceae. [ABSTRACT FROM AUTHOR]

Iodide is accumulated by the brown alga Saccharina japonica at a high concentration and has been proven to be an inorganic antioxidant that plays an important role in oxidative metabolism. Vanadium-dependent bromoperoxidases (vBPOs) and iodoperoxidases (vIPOs), which catalyze the oxidation of iodide, are essential for iodine accumulation and metabolism. Heavy metal pollutant cadmium (Cd) from anthropogenic activities can cause damage to algae mainly by producing oxidative stress. Here, the effects of iodine pretreatment on the stress of S. japonica caused by cadmium were analyzed. The growth experiment showed that iodine pretreatment could reduce the damage of low concentration cadmium on S. japonica young thalli. At the transcriptomic level, gene ontology (GO) enrichment analysis confirmed that cadmium stress could cause a peroxidation reaction in S. japonica. However, the most significant GO term was "photosystem I" in the series with iodine pretreatment. Weighted gene co-expression network analysis (WGCNA) indicated that iodine pretreatment alleviated cadmium stress responses of S. japonica by affecting the photosynthesis process. Analysis of the differentially expressed genes (DEGs) showed that five enzymes from the vBPO family and 13 enzymes from the vIPO family might play crucial roles in this process. [ABSTRACT FROM AUTHOR]

Brown seaweeds (Laminariaceae) vary considerably in the content of toxic and essential elements; these variations depend on the taxonomic group and geographical factors. Seaweeds are extensively used in the food industry and widely applied in medicine for both humans and animals. Therefore, it is relevant to examine the correlation between the elemental composition and the geographical origin of kelp thalli obtained from different sources.The aim of the study was to collect, collate, and analyse primary and secondary data on the accumulation of essential, toxic and potentially carcinogenic elements, including iodine, in the thalli of brown seaweeds (Laminariaceae).Materials and methods. This study investigated the concentrations of 17 elements in Laminaria spp. (Al, As, Cd, Cr, Co, Cu, Fe, Hg, Mn, Mo, Ni, Se, Pb, Sr, V, Zn, and I). Experiments were conducted on an Agilent 7900 inductively coupled plasma mass spectrometer. The authors studied publications on the elemental composition of brown seaweeds (Laminariaceae) using literature search and data analysis methods.Results. This article reflects the updated classification of brown seaweeds (Laminariaceae) and summarises information about the mechanisms by which iodine and other elements accumulate in the thallus. The authors established species-specific variations in the order of element uptake and in the accumulation of elemental toxicants. The mutual influence of elements on their accumulation in brown seaweeds (Laminariaceae) was evaluated using Spearman’s rank correlation coefficients.Conclusions. The study results can inform the implementation of a risk-based quality control strategy for herbal medicinal products aimed at reducing human exposure to toxic elements. The authors suggest that the upper limit of iodine content in kelp-based food products should be standardised.

Background: Glutathione S-transferase (GST) is a crucial enzyme for metabolism, detoxification, and stress resistance in organisms. Many GSTs have been identified in seaweeds, but the isolation and functional analysis of GSTs in Saccharina japonica have not been completed. Result: In this study, a total of 32 SjGST genes, localized on 10 scaffolds and 6 contigs, were identified and categorized into three groups. Most of these SjGSTs were presumed to be distributed in the cytoplasm. Tandem duplication had a significant influence on the expansion of the SjGST gene family. Functional analysis of cis-acting elements in the promoter regions demonstrated that SjGSTs enhance the stress resistance of the kelp. Quantitative real-time PCR tests confirmed that SjGSTs positively influence S. japonica sporophytes under stress from low salinity, drought, and high temperature. Recombinant yeast tests further affirmed the role of SjGSTs in stress resistance; SjGSTs improved the growth rate of recombinant yeast under 1.5 M NaCl or 8 mM H2O2. Analysis of biochemical parameters indicated that the optimum temperatures for SjGST20 and SjGST22 were 20 °C, and the optimum pH values were 7.0 and 8.0 for SjGST20 and SjGST22, respectively. The Km values for the substrate 1-chloro-2,4-dinitrobenzene (CDNB) were 2.706 mM and 0.674 mM and were 6.146 mM and 3.559 mM for the substrate glutathione (GSH) for SjGST20 and SjGST22, respectively. Conclusion: SjGSTs are important stress resistant genes in S. japonica. This research results will enhance our understanding the function of GSTs in brown seaweeds, and explained its functional roles in stress resistance in marine environments. [ABSTRACT FROM AUTHOR]

The brown seaweed, Sacchairna japonica, has been used in traditional Chinese medicine for over one thousand years. Oral administration of fucoidan or low molecular weight fucoidan (LMWF) from S. japonica could ameliorate kidney dysfunction in chronic kidney diseases and inhibit diabetic vascular complications. In many studies, LMWF was found to be more potent than fucoidan with high molecular weight. However, the pharmacokinetics of LMWF still remains unclear. The purpose of the research is to compare the pharmacokinetics of fucoidan with high molecular weight (136 kDa) with that low molecular weight (9.5 kDa) after oral administration to ICR mice. Since fucose is the main and representative monosaccharide of fucoidans, we evaluate the pharmacokinetics of fucoidan and LMWF by determining the fucose concentration in mice serum. Both fucoidan and LMWF were absorbed following oral administration. Fucoidan and LMWF were provided to mice by oral administration with 60 mg/kg and the maximum Concentration (Cmax) was found at 2.5 h (0.66±0.32 mg/L) for Fucoidan and 1.5 h (1.01±0.56 mg/L) for LMWF, respectively. It seems that LMWF had a higher area under the curve (AUC0−t) and was absorbed more quickly than fucoidan. The estimated bioavailability of LMWF was 28.3% in the mice treated with a single dose of 30 mg/kg. In addition, LMWF was found widely spreaded into different tissues following oral administration and the highest concentration was found in kidney at 19.93±7.02 µg/g. In this study, we first studied the pharmacokinetics of LMWF, in order to help to understand the function of LMWF. And our results shed light on the potential of development of drugs based on LMWF. [ABSTRACT FROM AUTHOR]

Nowadays, the exponential expansion in human population has resulted in the massification of intensive agricultural practices, with crop yield and sustainability being one of the most pressing challenges. Therefore, there was a need for new and natural fertilizers and pesticides, which has become a popular agricultural trend nowadays. Therefore, there was an increased interest to apply seaweed and bacterial extracts in agriculture to promote new means of sustainability and soil usage. This work aims to test seaweed inclusion in the agricultural field, as a simple or complex foliar biofertilizer solution applied together with a nitrifying bacteria, to verify if there is a potential synergistic effect of these two different types of biofertilizers on economically important vegetables. As a result, experiments were conducted in a greenhouse using an aqueous extract of the brown seaweed Saccharina latissima (1.2% v/v) and a biofertilizer based on BlueN bacteria (0.03% m/v), both simple or in combination, on lettuce (Lactuca sativa L. var. crispa) plants. The seaweed extract (simple or in combination), presented favorable effect on lettuce growth and nutritional properties. The aqueous algal extract, and it in combination with BlueN, produced heavier lettuce leaves (74.25 ± 6.86 and 74.13 ± 3.07 g, respectively) than the controls and enriched leaf micronutrient contents (zinc and manganese). Also, this study demonstrated that a combined seaweed-bacteria fertilizer did not show synergistic behavior, being a non-profitable solution when compared to a simple seaweed extract. In summary, this study demonstrated that simple (crude) seaweed extracts can be considered as an important key for natural plant biofertilizers and growth stimulators concerned with the blue circular economy. [ABSTRACT FROM AUTHOR]

Saccharina latissima is a brown seaweed that could be used in ruminant feeding, but its fast deteriorating and seasonal growth nature limit their utilisation in the practice. Ensiling could be used as a preservation method, but information of its effects on the nutritional value of the seaweed is limited. This study evaluated the in vitro ruminal fermentation of different S. latissima silages using ruminal inoculum either from goats fed a mixed diet (60:40 oat hay:concentrate) or from sheep fed a high-forage diet (90:10 alfalfa hay:concentrate) to simulate different small ruminant production systems. S. latissima was ensiled in vacuum bags without additives (Control), with formic acid (4 g/kg seaweed; FA), with lactic acid bacteria (LAB) or with LAB after a pre-wilting treatment to reach a seaweed dry matter (DM) content of 30% (30LAB). Ensiling S. latissima decreased (p < 0.05) the content in DM, neutral detergent fibre and total extractable polyphenols, but nitrogen and fat content were unaffected. For both ruminal inoculums, ensiling decreased (p < 0.05) the asymptotic gas production after 120 h of fermentation (excepting for FA silage with goats' inoculum), but the total volatile fatty acid (VFA) production was unaffected. The VFA profile shifted towards greater (p < 0.05) acetate and lower (p < 0.05) propionate proportions in all silages compared with the pre-ensiling S. latissima. When goats inoculum was used, greater (p < 0.05) CH4 production compared with pre-ensiling S. latissima was observed in all silages, except Control one, which led to greater (p < 0.05) CH4/total VFA ratio. In contrast, no differences among samples (p > 0.05) in either CH4 production or CH4/total VFA ratio were observed when sheep' inoculum was used. Fermentation of all samples started earlier with goats' inoculum than with sheep' inoculum, which was attributed to the different diet fed to the animals. These results suggest that ensiling S. latissima with either formic acid or lactic acid bacteria could be a viable conservation method to preserve the nutritive value. [ABSTRACT FROM AUTHOR]

Melanoma is the most aggressive and treatment-resistant form of skin cancer. It is phenotypically characterized by aerobic glycolysis that provides higher proliferative rates and resistance to cell death. The glycolysis regulation in melanoma cells by means of effective metabolic modifiers represents a promising therapeutic opportunity. This work aimed to assess the metabolically oriented effect and mechanism of action of fucoidan from the brown alga Saccharina cichorioides (ScF) and its carboxymethylated derivative (ScFCM) in combination with 2-deoxy-D-glucose (2-DG) on the proliferation and colony formation of human melanoma cell lines SK-MEL-28, SK-MEL-5, and RPMI-7951. The metabolic profile of melanoma cells was determined by the glucose uptake and Lactate-GloTM assays. The effect of 2-DG, ScF, ScFCM, and their combination on the proliferation, colony formation, and activity of glycolytic enzymes was assessed by the MTS, soft agar, and Western blot methods, respectively. When applied separately, 2-DG (IC50 at 72 h = 8.7 mM), ScF (IC50 at 72 h > 800 µg/mL), and ScFCM (IC50 at 72 h = 573.9 μg/mL) inhibited the proliferation and colony formation of SK-MEL-28 cells to varying degrees. ScF or ScFCM enhanced the inhibiting effect of 2-DG at low, non-toxic concentrations via the downregulation of Glut 1, Hexokinase II, PKM2, LDHA, and pyruvate dehydrogenase activities. The obtained results emphasize the potential of the use of 2-DG in combination with algal fucoidan or its derivative as metabolic modifiers for inhibition of melanoma SK-MEL-28 cell proliferation. [ABSTRACT FROM AUTHOR]

Seaweed is gaining interest as a sustainable source of protein. An often-used method for protein extraction from seaweed is alkaline extraction. In this study, the robustness of alkaline protein extraction was tested against protein extraction at neutral pH for sugar kelp (S. latissima) harvested at different time points and at different cultivation sites. The harvest time and place significantly influenced the total nitrogen (N) content of the bio-mass, the N extraction yield as % of biomass N, and the protein solubility. However, there was no specific pattern regarding harvest season and biomass age. The N extraction yield as % of biomass dry matter content was more similar between biomasses. The N extraction yield (56 of biomass N) varied from 1.59 % to 25.22 % (mean: 6.61 56) for the control extraction, whereas it was 5.32-52.96 % (mean: 16.03 %) for the alkaline extraction. Hence, the alkaline extraction increased the N yield, and gave a higher N concentration in the protein extracts and improved the solubility of the protein extracts across the different biomass batches compared to the control method at neutral pH. This states the robustpHness of the alkaline protein extraction for sugar kelp and suggests improved suitability in foods compared to the extraction at neutral pH. [ABSTRACT FROM AUTHOR]

The seaweed has a high content of easily degradable carbohydrates, making it a potential substrate for the production of γ-aminobutyric acid (GABA). In this study, response surface methodology pretreatment and enzymatic saccharification (Es) were conducted on a flask culture of Saccharina japonica seaweed. The optimal hydrolytic conditions were: 10.8% (w/v) slurry content, 0.7% H2SO4, and 121°C for 30 min. Es using enzyme cocktails (Celluclast 1.5 L + Viscozyme L) at 16 U/mL produced 6.26 g/L glucose with an efficiency of 92%. The concentrations of laminarin and fucose (prebiotics) were 10.4 and 0.48 g/L after pretreatment and saccharification, respectively. The suitable monosodium glutamate (MSG) addition was 2% (w/v), and further increase in MSG addition (3–5% (w/v)) had no significant effect on GABA production. The pyridoxal 5′-phosphate (10 µM) addition time of 48–72 h was determined based on the GABA fermentation. Adapted Levilactobacillus brevis KCL010 to high concentrations of mannitol improved the synbiotic fermentation efficiency of S. japonica hydrolysates, further improving the consumption of mixed monosaccharides. [ABSTRACT FROM AUTHOR]

Substitutability of broccoli by‐products (BBP) for Saccharina japonica in feed on growth, carcass chemical composition, and air exposure resistance of abalone (Haliotis discus) was investigated. One thousand and two hundred sixty abalones were randomly assigned into 18 cages (3 cages/diet; 70 abalone/cage). Two hundred g/kg of S. japonica was included in the control diet (BBP0). The BBP250, BBP500, BBP750, and BBP1000 diets were prepared by substituting 250, 500, 750, and 1000 g/kg of S. japonica with an equal amount of BBP. Additionally, dry S. japonica was prepared. Abalone were fed daily for 7 days a week for 16 weeks. Following the completion of the feeding trial, 20 abalone from each cage were exposed to air for 20 h prior to being monitored for the following 5 days. The greatest weight gain and specific growth rate (SGR) were achieved in abalone fed the BBP250 diet. Superior survival was obtained in abalone fed the BBP250, BBP500, BBP750, and BBP1000 diets to abalone fed the S. japonica control diet. The BBP250 and BBP500 diets achieved the highest survival of abalone. BBP appears to be a novel replacer for S. japonica in abalone diets, and 250 g/kg replacement of BBP for S. japonica produced the best weight gain and SGR. [ABSTRACT FROM AUTHOR]

Coastal habitats are increasingly recognized as fundamentally important components of global carbon cycles, but the rates of carbon flow associated with marine macrophytes are not well resolved for many species in many regions. We quantified density, rates of primary productivity, and detritus production of intertidal stands of two common intertidal kelp species—Laminaria digitata (oarweed) and Saccharina latissima (sugar kelp)—on four NE Atlantic rocky shores over 22 months. The density of L. digitata was greater at exposed compared to moderately exposed shores but remained consistently low for S. latissima throughout the survey period. Individual productivity and erosion rates of L. digitata did not differ between exposed and moderately exposed shores but differed across exposure levels throughout the year at moderately exposed sites only. Productivity and erosion of S. latissima remained low on moderately exposed shores and showed no clear seasonal pattern. Patterns of productivity and total detrital production (erosion and dislodgement) per m2 of both L. digitata and S. latissima followed closely that of densities per m2, peaking in May during both survey years. Temperature and light were key factors affecting the productivity rates of L. digitata and S. latissima. Erosion rates of L. digitata were affected by wave exposure, temperature, light, grazing, and epiphyte cover, but only temperature‐affected erosion of S. latissima. Production of biomass and detritus was greater in L. digitata than in S. latissima and exceeded previous estimates for subtidal and warmer‐water affinity kelp populations (e.g., Laminaria ochroleuca). These biogenic habitats are clearly important contributors to the coastal carbon cycle that have been overlooked previously and should be included in future ecosystem models. Further work is required to determine the areal extent of kelp stands in intertidal and shallow subtidal habitats, which is needed to scale up local production estimates to entire coastlines. [ABSTRACT FROM AUTHOR]

Kelp are important primary producers that are colonized by diverse microbes that can have both positive and negative effects on their hosts. The kelp microbiome could support the burgeoning kelp cultivation sector by improving host growth, stress tolerance, and resistance to disease. Fundamental questions about the cultivated kelp microbiome still need to be addressed before microbiome‐based approaches can be developed. A critical knowledge gap is how cultivated kelp microbiomes change as hosts grow, particularly following outplanting to sites that vary in abiotic conditions and microbial source pools. In this study we assessed if microbes that colonize kelp in the nursery stage persist after outplanting. We characterized microbiome succession over time on two species of kelp, Alaria marginata and Saccharina latissima, outplanted to open ocean cultivation sites in multiple geographic locations. We tested for host‐species specificity of the microbiome and the effect of different abiotic conditions and microbial source pools on kelp microbiome stability during the cultivation process. We found the microbiome of kelp in the nursery is distinct from that of outplanted kelp. Few bacteria persisted on kelp following outplanting. Instead, we identified significant microbiome differences correlated with host species and microbial source pools at each cultivation site. Microbiome variation related to sampling month also indicates that seasonality in host and/or abiotic factors may influence temporal succession and microbiome turnover in cultivated kelps. This study provides a baseline understanding of microbiome dynamics during kelp cultivation and highlights research needs for applying microbiome manipulation to kelp cultivation. [ABSTRACT FROM AUTHOR]

We describe the current state of speciation in the species complex of the marine gastropod Patelloida saccharina , using mitochondrial COI , 16S RNA, nuclear histone 3 gene and single-nucleotide polymorphism (SNP) markers from 165 specimens collected from 37 localities across the Japanese archipelago. In total, 28 unique COI haplotypes, 16 16S haplotypes, 11 histone 3 haplotypes and 148 734 SNPs were obtained. Genetic assignments and phylogenetic trees recovered three genetically distinct lineages: P. saccharina saccharina , P. saccharina lanx and an unknown P. sp. from Shionomisaki, Wakayama Prefecture. The divergence between P. saccharina saccharina and P. saccharina lanx was estimated to have occurred around 44 000 years ago—too recent to have accumulated the morphological differences that have confounded taxonomic identification. Continuous gene exchange after an initial split is suggested based on demographic history analyses, which allowed for introgression of the P. saccharina lanx genome and the proliferation of intermediate individuals. Speciation, despite the existence of a contact zone in the Ryukyu Islands, possibly occurred due to the eventual reproductive isolation that followed the initial split with gene flow. Patelloida saccharina saccharina and P. saccharina lanx were strongly supported by our results as two separate species, and a revision of the current taxonomic descriptions based on their phylogeny, demographic history and species distribution is proposed. [ABSTRACT FROM AUTHOR]

Background: Macroalgal epiphytic microbial communities constitute a rich resource for novel enzymes and compounds, but studies so far largely focused on tag-based microbial diversity analyses or limited metagenome sequencing of single macroalgal species. Results: We sampled epiphytic bacteria from specimens of Ulva sp. (green algae), Saccharina sp. (brown algae), Grateloupia sp. and Gelidium sp. (both red algae) together with seawater and sediment controls from a coastal reef in Weihai, China, during all seasons. Using 16S rRNA amplicon sequencing, we identified 14 core genera (consistently present on all macroalgae), and 14 dominant genera (consistently present on three of the macroalgae). Core genera represented ~ 0.7% of all genera, yet accounted for on average 51.1% of the bacterial abundances. Plate cultivation from all samples yielded 5,527 strains (macroalgae: 4,426) representing 1,235 species (685 potentially novel). Sequencing of selected strains yielded 820 non-redundant draft genomes (506 potentially novel), and sequencing of 23 sampled metagenomes yielded 1,619 metagenome-assembled genomes (MAGs), representing further 1,183 non-redundant genomes. 230 isolates and 153 genomes were obtained from the 28 core/dominant genera. We analyzed the genomic potential of phycosphere bacteria to degrade algal polysaccharides and to produce bioactive secondary metabolites. We predicted 4,451 polysaccharide utilization loci (PULs) and 8,810 biosynthetic gene clusters (BGCs). These were particularly prevalent in core/dominant genera. Conclusions: Our metabolic annotations and analyses of MAGs and genomes provide new insights into novel species of phycosphere bacteria and their ecological niches for an improved understanding of the macroalgal phycosphere microbiome. DnRc39z963CYrL7RdN5UNd Video Abstract [ABSTRACT FROM AUTHOR]

Supplementing ruminants' diet with seaweed has shown positive effect on meat quality and micronutrients important for human health. The objective of the present study was to investigate the use of Saccharina latissima in a lamb diet to improve the eating quality and nutritional value of meat. Six-month-old female Norwegian White lambs (n = 24) were fed, 35 days pre-slaughter, three different diets: a control (CON) and two seaweed diets (SW); supplemented with either 2.5% (SW1) or 5% (SW2). The quality properties of longissimus thoracis et lumborum (LTL) and semimembranosus with adductor (SM+ADD) muscles were examined. The dietary inclusion of seaweed reduced cooking loss and shear force of lamb meat, although the effect was not significant at both supplementation levels. SW1 fed lambs showed a significantly (p < 0.05) improved meat color stability and antioxidant potential. Seaweed also reduced lipid oxidation (TBARS) and the warm-over flavor in SM+ADD compared to the CON lamb. Seaweed fed lambs showed an increased content of selenium and iodine in LTL, thereby fulfilling the requirements for the label "source of nutrient" and "significant source of nutrient", respectively. An increased arsenic content in LTL was, however, also observed with seaweed inclusion (to 1.54 and 3.09 μg/100 g in SW1 and SW2 group, respectively). While relevant positive effects were found in meat using seaweed in lamb feed, some optimization of this feed approach will be desirable. [ABSTRACT FROM AUTHOR]

Introduction: Saccharina latissima is a canopy-forming species of brown algae and, as such, is considered an ecosystem engineer. Several populations of this alga are exploited worldwide, and a decrease in the abundance of S. latissima at its southern distributional range limits has been observed. Despite its economic and ecological interest, only a few data are available on the composition of microbiota associated with S. latissima and its role in algal physiologyn. Methods: We studied the whole bacterial community composition associated with S. latissima samples from three locations (Brittany, Helgoland, and Skagerrak) by 16S metabarcoding analyses at different scales: algal blade part, regions, season (at one site), and algal physiologic state. Results and Discussion: We have shown that the difference in bacterial composition is driven by factors of decreasing importance: (i) the algal tissues (apex/meristem), (ii) the geographical area, (iii) the seasons (at the Roscoff site), and (iv) the algal host's condition (healthy vs. symptoms). Overall, Alphaproteobacteria, Gammaproteobacteria, and Bacteroidia dominated the general bacterial communities. Almost all individuals hosted bacteria of the genus Granulosicoccus, accounting for 12% of the total sequences, and eight additional core genera were identified. Our results also highlight a microbial signature characteristic for algae in poor health independent of the disease symptoms. Thus, our study provides a comprehensive overview of the S. latissima microbiome, forming a basis for understanding holobiont functioning. [ABSTRACT FROM AUTHOR]

Calmodulins (CaMs) and Calmodulin-like proteins (CMLs) are vital in plant growth, development, and stress responses. However, CaMs and CMLs have not been fully identified and characterized in brown algae, which has been evolving independently of the well-studied green plant lineage. In this study, whole-genome searches revealed one SjCaM and eight SjCMLs in Saccharina japonica, and one EsCaM and eleven EsCMLs in Ectocarpus sp. SjCaM and EsCaM encoded identical protein products and shared 88.59–89.93% amino acid identities with Arabidopsis thaliana AtCaMs, thereby indicating that brown algae CaMs retained a similar Ca2+ sensors function as in plants. The phylogenetic and gene structure analysis results showed that there was significant divergence in the gene sequences among brown algae CMLs. Furthermore, evolutionary analysis indicated that the function of brown alga CMLs was relatively conserved, which may be related to the fact that brown algae do not need to face complex environments like terrestrial plants. Regulatory elements prediction and the expression analysis revealed the probable functioning of SjCaM/CML genes in gametophyte development and the stress response in S. japonica. In addition, the SjCaM/SjCMLs interacting proteins and chemicals were preliminarily predicted, suggesting that SjCaM/SjCMLs might play putative roles in Ca2+/CaM-mediated growth and development processes and stimulus responses. Therefore, these results will facilitate our understanding of the evolution of brown algae CaMs/CMLs and the functional identification of SjCaM/SjCMLs. [ABSTRACT FROM AUTHOR]

Kelp species are distributed along ~ 25% of the world's coastlines and the forests they form represent some of the world's most productive and diverse ecosystems. Like other marine habitat–formers, the associated microbial community is fundamental for host and, in turn, wider ecosystem functioning. Given there are thousands of bacteria-host associations, determining which relationships are important remains a major challenge. We characterised the associated bacteria of two habitat-forming kelp species, Laminaria hyperborea and Saccharina latissima, from eight sites across a range of spatial scales (10 s of metres to 100 s of km) in the northeast Atlantic. We found no difference in diversity or community structure between the two kelps, but there was evidence of regional structuring (across 100 s km) and considerable variation between individuals (10 s of metres). Within sites, individuals shared few amplicon sequence variants (ASVs) and supported a very small proportion of diversity found across the wider study area. However, consistent characteristics between individuals were observed with individual host communities containing a small conserved "core" (8–11 ASVs comprising 25 and 32% of sample abundances for L. hyperborea and S. latissima, respectively). At a coarser taxonomic resolution, communities were dominated by four classes (Planctomycetes, Gammaproteobacteria, Alphaproteobacteria and Bacteroidia) that made up ~ 84% of sample abundances. Remaining taxa (47 classes) made up very little contribution to overall abundance but the majority of taxonomic diversity. Overall, our study demonstrates the consistent features of kelp bacterial communities across large spatial scales and environmental gradients and provides an ecologically meaningful baseline to track environmental change. [ABSTRACT FROM AUTHOR]

Fucoidans from brown algae are described as anti-inflammatory, antioxidative, and antiangiogenic. We tested two Saccharina latissima fucoidans (SL-FRO and SL-NOR) regarding their potential biological effects against age-related macular degeneration (AMD). Primary porcine retinal pigment epithelium (RPE), human RPE cell line ARPE-19, and human uveal melanoma cell line OMM-1 were used. Cell survival was assessed in tetrazolium assay (MTT). Oxidative stress assays were induced with erastin or H2O2. Supernatants were harvested to assess secreted vascular endothelial growth factor A (VEGF-A) in ELISA. Barrier function was assessed by measurement of trans-epithelial electrical resistance (TEER). Protectin (CD59) and retinal pigment epithelium-specific 65 kDa protein (RPE65) were evaluated in western blot. Polymorphonuclear elastase and complement inhibition assays were performed. Phagocytosis of photoreceptor outer segments was tested in a fluorescence assay. Secretion and expression of proinflammatory cytokines were assessed with ELISA and real-time PCR. Fucoidans were chemically analyzed. Neither toxic nor antioxidative effects were detected in ARPE-19 or OMM-1. Interleukin 8 gene expression was slightly reduced by SL-NOR but induced by SL-FRO in RPE. VEGF secretion was reduced in ARPE-19 by SL-FRO and in RPE by both fucoidans. Polyinosinic:polycytidylic acid induced interleukin 6 and interleukin 8 secretion was reduced by both fucoidans in RPE. CD59 expression was positively influenced by fucoidans, and they exhibited a complement and elastase inhibitory effect in cell-free assay. RPE65 expression was reduced by SL-NOR in RPE. Barrier function of RPE was transiently reduced. Phagocytosis ability was slightly reduced by both fucoidans in primary RPE but not in ARPE-19. Fucoidans from Saccharina latissima, especially SL-FRO, are promising agents against AMD, as they reduce angiogenic cytokines and show anti-inflammatory and complement inhibiting properties; however, potential effects on gene expression and RPE functions need to be considered for further research. [ABSTRACT FROM AUTHOR]

Macroalgae are a new food source in the Western world. The purpose of this study was to evaluate the impact of harvest months and food processing on cultivated Saccharina latissima (S. latissima) from Quebec. Seaweeds were harvested in May and June 2019 and processed by blanching, steaming, and drying with a frozen control condition. The chemical (lipids, proteins, ash, carbohydrates, fibers) and mineral (I, K, Na, Ca, Mg, Fe) compositions, the potential bioactive compounds (alginates, fucoidans, laminarans, carotenoids, polyphenols) and in vitro antioxidant potential were investigated. The results showed that May specimens were significantly the richest in proteins, ash, I, Fe, and carotenoids, while June macroalgae contained more carbohydrates. The antioxidant potential of water-soluble extracts (Oxygen Radical Absorbance Capacity [ORAC] analysis–625 µg/mL) showed the highest potential in June samples. Interactions between harvested months and processing were demonstrated. The drying process applied in May specimens appeared to preserve more S. latissima quality, whereas blanching and steaming resulted in a leaching of minerals. Losses of carotenoids and polyphenols were observed with heating treatments. Water-soluble extracts of dried May samples showed the highest antioxidant potential (ORAC analysis) compared to other methods. Thus, the drying process used to treat S. latissima harvested in May seems to be the best that should be selected. [ABSTRACT FROM AUTHOR]

Saccharina japonica belongs to brown macro-alga with various potential health benefits; its antioxidant and anti-inflammatory activities indicate the potential to improve inflammatory bowel diseases. Here, the potential anti-colitis effect of Saccharina japonica extract (SJE) was evaluated on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in C57B/L6 mice. The mice were treated with mesalazine (MES) and various doses of SJE by gavage for 14 days. Results showed that both MES and SJE treatment decreased the disease activity index scores, relieving the short colon. SJE increased the occludin and zonula occludens-1 levels, and the beneficial effects were better than MES. MES and SJE exerted similar effects in decreasing inflammatory cytokines and oxidative stress. Moreover, SJE reshaped the intestinal microbiota by increasing α-diversity and reducing plenty of harmful bacteria. Dietary SJE was significant to relieving the reduction in short-chain fatty acids. The results revealed the protective effect of SJE on colitis and potential mechanisms, which is important for the rational use of SJE in UC prevention. [ABSTRACT FROM AUTHOR]

Cancer is one of the main causes of human mortality worldwide. Despite the advances in the diagnostics, surgery, radiotherapy, and chemotherapy, the search for more effective treatment regimens and drug combinations are relevant. This work aimed to assess the radiomodifying effect and molecular mechanism of action of fucoidan from the brown alga Saccharina cichorioides (ScF) and product of its autohydrolysis (ScF_AH) in combination with pacificusoside D from the starfish Solaster pacificus (SpD) on the model of viability and invasion of three-dimension (3D) human melanoma cells SK-MEL-2. The cytotoxicity of ScF (IC50 JB6 Cl41 > 800 µg/mL; IC50 SK-MEL-2 = 685.7 µg/mL), ScF_AH (IC50 JB6 Cl41/SK-MEL-2 > 800 µg/mL), SpD (IC50 JB6 Cl41 = 22 µM; IC50 SK-MEL-2 = 5.5 µM), and X-ray (ID50 JB6 Cl41 = 11.7 Gy; ID50 SK-MEL-2 = 6.7 Gy) was determined using MTS assay. The efficiency of two-component treatment of 3D SK-MEL-2 cells was revealed for ScF in combination with SpD or X-ray but not for the combination of fucoidan derivative ScF_AH with SpD or X-ray. The pre-treatment of spheroids with ScF, followed by cell irradiation with X-ray and treatment with SpD (three-component treatment) at low non-toxic concentrations, led to significant inhibition of the spheroids' viability and invasion and appeared to be the most effective therapeutic scheme for SK-MEL-2 cells. The molecular mechanism of radiomodifying effect of ScF with SpD was associated with the activation of the initiator and effector caspases, which in turn caused the DNA degradation in SK-MEL-2 cells as determined by the Western blotting and DNA comet assays. Thus, the combination of fucoidan from brown algae and triterpene glycoside from starfish with radiotherapy might contribute to the development of highly effective method for melanoma therapy. [ABSTRACT FROM AUTHOR]