Natural Bioactive Compounds from Macroalgae and Microalgae for the Treatment of Alzheimer's Disease: A Review.

Neuroinflammation, toxic protein aggregation, oxidative stress, and mitochondrial dysfunction are key pathways in neurodegenerative diseases like Alzheimer's disease (AD). Targeting these mechanisms with antioxidants, anti-inflammatory compounds, and inhibitors of Aß formation and aggregation is crucial for treatment. Marine algae are rich sources of bioactive compounds, including carbohydrates, phenolics, fatty acids, phycobiliproteins, carotenoids, fatty acids, and vitamins. In recent years, they have attracted interest from the pharmaceutical and nutraceutical industries due to their exceptional biological activities, which include anti-inflammation, antioxidant, anticancer, and anti-apoptosis properties. Multiple lines of evidence have unveiled the potential neuroprotective effects of these multifunctional algal compounds for application in treating and managing AD. This article will provide insight into the molecular mechanisms underlying the neuroprotective effects of bioactive compounds derived from algae based on in vitro and in vivo models of neuroinflammation and AD. We will also discuss their potential as disease-modifying and symptomatic treatment strategies for AD.

Chloroplast DNA methylation in the kelp Saccharina latissima is determined by origin and possibly influenced by cultivation.

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.

Comparative evaluation of the antihyperglycemic effects of three extracts of sea mustard (Undaria pinnatifida): In vitro and in vivo studies.

Undaria pinnatifida (UP) contains multiple bioactive substances, such as polyphenols, polysaccharides, and amino acids, which are associated with various biological properties. This study aimed to evaluate the antihyperglycemic effects of three extracts obtained from UP. UP was extracted under three different conditions: a low-temperature water extract at 50 °C (UPLW), a high-temperature water extract at 90 °C (UPHW), and a 70 % ethanol extract (UPE). Nontargeted chemical profiling using high-performance liquid chromatography-triple/time-of-flight mass spectrometry (HPLC-Triple TOF-MS/MS) was conducted on the three UP extracts. Subsequently, α-glucosidase inhibitory (AGI) activity, glucose uptake, and the mRNA expression of sodium/glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2) were evaluated in Caco-2 cell monolayers. Furthermore, an oral carbohydrate tolerance test was performed on C57BL/6 mice. The mice were orally administered UP at 300 mg/kg body weight (B.W.), and the blood glucose level and area under the curve (AUC) were measured. Compared with glucose, UPLW, UPHW and UPE significantly inhibited both glucose uptake and the mRNA expression of SGLT1 and GLUT2 in Caco-2 cell monolayers. After glucose, maltose, and sucrose loading, the blood glucose levels and AUC of the UPLW group were significantly lower than those of the control group. These findings suggest that UPLW has antihyperglycemic effects by regulating glucose uptake through glucose transporters and can be expected to alleviate postprandial hyperglycemia. Therefore, UPLW may have potential as a functional food ingredient for alleviating postprandial hyperglycemia.

Impact of environmental factors changes induced by marine heatwaves and heavy precipitation on antibiotic toxicity to Isochrysis galbana: Implications for climate change adaptation.

Isochrysis galbana, a crucial primary producer and food source in aquatic ecosystems, faces increasing challenges from climate change and emerging contaminants like antibiotics. This study investigates the combined effects of sudden temperature increase (representing marine heatwaves) and rapid salinity change (representing extreme precipitation events) on the toxicity of tetracycline (TC) and oxytetracycline (OTC) to I. galbana. Short-term experiments reveal heightened antibiotic toxicity at 31 °C or salinities of 18 PSU, surpassing algal tolerance limits. Long-term tests show decreased inhibition of algal growth on day 9, indicating algal adaptation to the environment. Analyses of photosynthesis II efficiency, pigment content, and macromolecular composition support this, suggesting adaptation mechanism activation. While algae acclimate to the environment during long-term antibiotic exposure, extreme weather conditions may compromise this adaptation. These findings have implications for managing antibiotics in aquatic environments under climate change.

Deciphering inhibitory activity of marine algae Ecklonia cava phlorotannins against SARS CoV-2 main protease: A coupled in-silico docking and molecular dynamics simulation study.

The onset of COVID-19 due to the SARS CoV-2 virus has spurred an urgent need for potent therapeutics and vaccines to combat this global pandemic. The main protease (Mpro) of the virus, crucial in its replication, has become a focal point in developing anti-COVID-19 drugs. The cysteine protease Mpro in SARS CoV-2 bears a significant resemblance to the same protease found in SARS CoV-1. Previous research highlighted phlorotannins derived from Ecklonia cava, an edible marine algae, as inhibitors of SARS CoV-1 Mpro activity. However, it remains unclear whether these marine-derived phlorotannins also exert a similar inhibitory effect on SARS CoV-2 Mpro. To unravel this, our study utilized diverse in-silico methodologies. We explored the pharmacological potential of various phlorotannins (phloroglucinol, triphloretol-A, eckol, 2-phloroeckol, 7-phloroeckol, fucodiphloroethol G, dieckol, and phlorofucofuroeckol-A) and assessed their binding efficacies alongside established Mpro inhibitors (N3 and lopinavir) through molecular docking studies. Among these compounds, five phlorotannins (eckol, 2-phloroeckol, 7-phloroeckol, dieckol, and phlorofucofuroeckol-A) exhibited potent binding affinities comparable to or surpassing N3 and lopinavir, interacting especially with the catalytic residues His41 and Cys145 of Mpro. Moreover, molecular dynamics simulations revealed that these five Mpro-phlorotannin complexes displayed enhanced stability and maintained comparable or slightly reduced compactness. They exhibited reduced conformational changes and increased expansion relative to the Mpro-N3 and/or Mpro-lopinavir complex. Our MM-GBSA analysis further supported these findings. Overall, our investigation highlights the potential of these five phlorotannins in inhibiting the proteolytic function of SARS CoV-2 Mpro, offering promise for anti-COVID-19 drug development.

Assessing the role of the graphene family nanomaterials (GFNs: Graphene, GO, rGO) in modifying the toxicity potential and environmental risk of flame retardant, tetrabromobisphenol-A (TBBPA) in the marine microalgae Chlorella sp.

In recent years, a growing concern has emerged regarding the environmental implications of flame retardants (FRs) like tetrabromobisphenol-A (TBBPA) and graphene family nanomaterials (GFNs), such as graphene, graphene oxide (GO), and reduced graphene oxide (rGO), on marine biota. Despite these substances' well-established individual toxicity profiles, there is a notable gap in understanding the physicochemical interactions within the binary mixtures and consequent changes in the toxicity potential. Therefore, our research focuses on elucidating the individual and combined toxicological impacts of TBBPA and GFNs on the marine alga Chlorella sp. Employing a suite of experimental methodologies, including Raman spectroscopy, contact angle measurements, electron microscopy, and chromatography, we examined the physicochemical interplay between the GFNs and TBBPA. The toxicity potentials of individual constituents and their binary combinations were assessed through growth inhibition assays, quantifying reactive oxygen species (ROS) generation and malondialdehyde (MDA) production, photosynthetic activity analyses, and various biochemical assays. The toxicity of TBBPA and graphene-based nanomaterials (GFNs) was examined individually and in combinations. Both pristine TBBPA and GFNs showed dose-dependent toxicity. While lower TBBPA concentrations exacerbated toxicity in binary mixtures, higher TBBPA levels reduced the toxic effects compared to pristine TBBPA treatments. The principal mechanism underlying toxicity was ROS generation, resulting in membrane damage and perturbation of photosynthetic parameters. Cluster heatmap and Pearson correlation were employed to assess correlations between the biological parameters. Finally, ecological risk assessment was undertaken to evaluate environmental impacts of the individual components and the mixture in the algae.

Genomic characterisation and ecological distribution of Mantoniella tinhauana: a novel Mamiellophycean green alga from the Western Pacific.

Mamiellophyceae are dominant marine algae in much of the ocean, the most prevalent genera belonging to the order Mamiellales: Micromonas, Ostreococcus and Bathycoccus, whose genetics and global distributions have been extensively studied. Conversely, the genus Mantoniella, despite its potential ecological importance, remains relatively under-characterised. In this study, we isolated and characterised a novel species of Mamiellophyceae, Mantoniella tinhauana, from subtropical coastal waters in the South China Sea. Morphologically, it resembles other Mantoniella species; however, a comparative analysis of the 18S and ITS2 marker genes revealed its genetic distinctiveness. Furthermore, we sequenced and assembled the first genome of Mantoniella tinhauana, uncovering significant differences from previously studied Mamiellophyceae species. Notably, the genome lacked any detectable outlier chromosomes and exhibited numerous unique orthogroups. We explored gene groups associated with meiosis, scale and flagella formation, shedding light on species divergence, yet further investigation is warranted. To elucidate the biogeography of Mantoniella tinhauana, we conducted a comprehensive analysis using global metagenomic read mapping to the newly sequenced genome. Our findings indicate this species exhibits a cosmopolitan distribution with a low-level prevalence worldwide. Understanding the intricate dynamics between Mamiellophyceae and the environment is crucial for comprehending their impact on the ocean ecosystem and accurately predicting their response to forthcoming environmental changes.

Exploring potential polysaccharide utilization loci involved in the degradation of typical marine seaweed polysaccharides by Bacteroides thetaiotaomicron.

Introduction: Research on the mechanism of marine polysaccharide utilization by Bacteroides thetaiotaomicron has drawn substantial attention in recent years. Derived from marine algae, the marine algae polysaccharides could serve as prebiotics to facilitate intestinal microecological balance and alleviate colonic diseases. Bacteroides thetaiotaomicron, considered the most efficient degrader of polysaccharides, relates to its capacity to degrade an extensive spectrum of complex polysaccharides. Polysaccharide utilization loci (PULs), a specialized organization of a collection of genes-encoded enzymes engaged in the breakdown and utilization of polysaccharides, make it possible for Bacteroides thetaiotaomicron to metabolize various polysaccharides. However, there is still a paucity of comprehensive studies on the procedure of polysaccharide degradation by Bacteroides thetaiotaomicron. Methods: In the current study, the degradation of four kinds of marine algae polysaccharides, including sodium alginate, fucoidan, laminarin, and Pyropia haitanensis polysaccharides, and the underlying mechanism by Bacteroides thetaiotaomicron G4 were investigated. Pure culture of Bacteroides thetaiotaomicron G4 in a substrate supplemented with these polysaccharides were performed. The change of OD600, total carbohydrate contents, and molecular weight during this fermentation were determined. Genomic sequencing and bioinformatic analysis were further performed to elucidate the mechanisms involved. Specifically, Gene Ontology (GO) annotation, Clusters of Orthologous Groups (COG) annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were utilized to identify potential target genes and pathways. Results: Underlying target genes and pathways were recognized by employing bioinformatic analysis. Several PULs were found that are anticipated to participate in the breakdown of these four polysaccharides. These findings may help to understand the interactions between these marine seaweed polysaccharides and gut microorganisms. Discussion: The elucidation of polysaccharide degradation mechanisms by Bacteroides thetaiotaomicron provides valuable insights into the utilization of marine polysaccharides as prebiotics and their potential impact on gut health. Further studies are warranted to explore the specific roles of individual PULs and their contributions to polysaccharide metabolism in the gut microbiota.

Marinomonas rhodophyticola sp. nov. and Marinomonas phaeophyticola sp. nov., isolated from marine algae.

Two Gram-stain-negative, facultatively aerobic, and motile rod bacteria, designated as strains KJ51-3T and 15G1-11T, were isolated from marine algae collected in the Republic of Korea. Both strains exhibited catalase- and oxidase-positive activities. Optimum growth conditions for strain KJ51-3T were observed at 30 °C and pH 6.0-8.0, with 1.0-7.0 % (w/v) NaCl, whereas strain 15G1-11T exhibited optimal growth at 30 °C, pH 7.0, and 1.0-5.0 % NaCl. Major fatty acids detected in both strains included C16 : 0, C10 : 0 3-OH and summed features 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). As for polar lipids, strain KJ51-3T contained phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol, and two unidentified phospholipids, whereas strain 15G1-11T had PE, PG, and an unidentified aminolipid. Ubiquinone-8 was the predominant respiratory quinone in both strains, with minor detection of ubiquinone-9 in strain KJ51-3T. The genomic DNA G+C contents were 44.0 mol% for strain KJ51-3T and 40.5 mol% for strain 15G1-11T. Phylogenetic analyses based on both 16S rRNA gene and genome sequences placed strains KJ51-3T and 15G1-11T into distinct lineages within the genus Marinomonas, most closely related to Marinomonas arctica 328T (98.6 %) and Marinomonas algicola SM1966T (98.3 %), respectively. Strains KJ51-3T and 15G1-11T exhibited a 94.6 % 16S rRNA gene sequence similarity and a 70.7 % average nucleotide identity (ANI), with ANI values of 91.9 and 79.3 % between them and M. arctica 328T and M. algicola SM1966T, respectively, indicating that they represent novel species. In summary, based on their phenotypic, chemotaxonomic, and phylogenetic properties, strains KJ51-3T and 15G1-11T are proposed to represent novel species within the genus Marinomonas, for which the names Marinomonas rhodophyticola sp. nov. (KJ51-3T=KACC 22756T=JCM 35591T) and Marinomonas phaeophyticola sp. nov. (15G1-11T=KACC 22593T=JCM 35412T) are respectively proposed.

An investigation on antimicrobial and anticancer competence of macro red algae under in-vitro condition.

The purpose of this study was to look into the proximate parameters (moisture, ash, total fat, protein, and total carbohydrate), mineral composition (Fe, Cu, Mg, and Zn), antimicrobial as well as cytotoxic (anticancer) properties of extracts from the marine red macro algae Gracilaria corticata, Chondrus ocellatus, and Posphyra perforata against a few prevalent microbial pathogens (Salmonella typhi, Streptococcus pneumoniae, Corynebacterium diphtheriae, Clostridium tetani, and Treponema pallidum as well as fungal pathogens such as Candida albicans, Aspergillus niger, and Cryptococcus neoformans) and two cancerous cell lines (HeLa and MCF7). The dry biomass of these red algae biomass contains considerable valuable proximate parameters and minerals. The diffusion technique on agar wells was used to evaluate the antimicrobial properties of these test red algae methanol and hexane extract; MTT assay was used to evaluate the cytotoxic effects of the methanol and hexane extracts on each cancer cell line. The methanol extracts demonstrated significant antimicrobial activity against most of the tested pathogenic organisms. Mortality of cells was effectively caused by methanol extract and it followed by hexane extract at increased dosage 10 mg mL-1. The MTT assay revealed that the methanol extract of the red algae was considerably cytotoxic to HeLa and MCF7 cells, accompanied by the hexane extract in a dose-dependent manner. These findings suggest that the methanol extract of these red algae may contain bioactive compounds with antimicrobial and anticancer properties, which could be studied for future use in the discovery of new drugs from marine ecosystems.

Multiple marine algae identification based on three-dimensional fluorescence spectroscopy and multi-label convolutional neural network.

Accurate identification of algal populations plays a pivotal role in monitoring seawater quality. Fluorescence-based techniques are effective tools for quickly identifying different algae. However, multiple coexisting algae and their similar photosynthetic pigments can constrain the efficacy of fluorescence methods. This study introduces a multi-label classification model that combines a specific Excitation-Emission matric convolutional neural network (EEM-CNN) with three-dimensional (3D) fluorescence spectroscopy to detect single and mixed algal samples. Spectral data can be input directly into the model without transforming into images. Rectangular convolutional kernels and double convolutional layers are applied to enhance the extraction of balanced and comprehensive spectral features for accurate classification. A dataset comprising 3D fluorescence spectra from eight distinct algae species representing six different algal classes was obtained, preprocessed, and augmented to create input data for the classification model. The classification model was trained and validated using 4448 sets of test samples and 60 sets of test samples, resulting in an accuracy of 0.883 and an F1 score of 0.925. This model exhibited the highest recognition accuracy in both single and mixed algae samples, outperforming comparative methods such as ML-kNN and N-PLS-DA. Furthermore, the classification results were extended to three different algae species and mixed samples of skeletonema costatum to assess the impact of spectral similarity on multi-label classification performance. The developed classification models demonstrated robust performance across samples with varying concentrations and growth stages, highlighting CNN's potential as a promising tool for the precise identification of marine algae.

Marine algae: A treasure trove of bioactive anti-inflammatory compounds.

This comprehensive review examines the diverse classes of pharmacologically active compounds found in marine algae and their promising anti-inflammatory effects. The review covers various classes of anti-inflammatory compounds sourced from marine algae, including phenolic compounds, flavonoids, terpenoids, caretenoids, alkaloids, phlorotannins, bromophenols, amino acids, peptides, proteins, polysaccharides, and fatty acids. The anti-inflammatory activities of marine algae-derived compounds have been extensively investigated using in vitro and in vivo models, demonstrating their ability to inhibit pro-inflammatory mediators, such as cytokines, chemokines, and enzymes involved in inflammation. Moreover, marine algae-derived compounds have exhibited immunomodulatory properties, regulating immune cell functions and attenuating inflammatory responses. Specific examples of compounds with notable anti-inflammatory activities are highlighted. This review provides valuable insights for researchers in the field of marine anti-inflammatory pharmacology and emphasizes the need for further research to harness the pharmacological benefits of marine algae-derived compounds for the development of effective and safe therapeutic agents.

Novel insights into crystal violet dye adsorption onto various macroalgae: Comparative study, recyclability and overview of chromium (VI) removal.

In this study, effective biomaterials were prepared from marine macroalgae, namely Fucus spiralis (F.S), Ulva intestinalis (U.I), and Corallina officinalis (C.O). The ability to adsorb the hazardous organic dye crystal violet (CV) was examined, revealing different adsorptive properties for the three algae. The removal of CV dye occurred onto only a homogeneous monolayer for F.S, and both a homogeneous monolayer and a heterogeneous multilayer for U.I and C.O algae. The predicted monolayer capacities at 25 °C were approximately 53 mg/g, 55 mg/g, and 97 mg/g for F.S, C.O, and U.I, respectively. The adsorption of CV dye on all the algae was found to follow a pseudo-second-order rate. Ulva intestinalis algae, as a potential adsorbent of CV dye, were also tested in the adsorption of inorganic substances and demonstrated significant efficiency in the removal of chromium (VI). The findings highlight various adsorption properties and the relevance of macroalgae for wastewater treatment applications.

EPS-corona formation on graphene family nanomaterials (GO, rGO and graphene) and its role in mitigating their toxic effects in the marine alga Chlorella sp.

GFNs have widespread applications but can harm marine systems due to excessive use and improper disposal. Algae-secreted EPS can mitigate nanomaterial harm, but their impact on GFN toxicity is understudied. Hence, in the present study, we investigated the toxicity of three GFNs, graphene oxide (GO), reduced graphene oxide (rGO), and graphene, in pristine and EPS-adsorbed forms in the marine alga Chlorella sp. At an environmentally relevant concentration of 1 mgL-1, all three GFNs induced considerable oxidative stress and impeded growth and photosynthetic activity of the algae. The order of the toxic potential followed GO > rGO > graphene. The various facets of adsorption of EPS (1:1 mixture of loosely bound, and tightly bound EPS) on GFNs were investigated through microscopy, surface chemical analyses, fluorescence quenching studies, and isotherm and kinetics studies. Amongst the pristine GFNs treated with algal cells, GO was found to exert the maximum negative effects on algal growth. Upon adsorption of EPS over the GFNs, a significant decline in growth inhibition was observed compared to the respective pristine forms which strongly correlated with reduced oxidative stress and enhanced photosynthetic parameters in the cells. The formation of a layer of eco-corona after interaction of GFNs with EPS possibly caused a barrier effect which in turn diminished their toxic potential. The findings from the present investigation offer valuable insights into the environmental toxicity of GFNs and show that the eco-corona formation may lessen the risk posed by these materials in the marine environment.

The comparative effects of visible light and UV-A radiation on the combined toxicity of P25 TiO2 nanoparticles and polystyrene microplastics on Chlorella sp.

The ubiquitous presence of TiO2 nanoparticles (nTiO2) and microplastics (MPs) in marine ecosystems has raised serious concerns about their combined impact on marine biota. This study investigated the combined toxic effect of nTiO2 (1 mg/L) and NH2 and COOH surface functionalized polystyrene MPs (PSMPs) (2.5 and 10 mg/L) on Chlorella sp. All the experiments were carried out under both visible light and UV-A radiation conditions to elucidate the impact of light on the combined toxicity of these pollutants. Growth inhibition results indicated that pristine nTiO2 exhibited a more toxic effect (38%) under UV-A radiation when compared to visible light conditions (27%). However, no significant change in the growth inhibitory effects of pristine PSMPs was observed between visible light and UVA radiation conditions. The combined pollutants (nTiO2 + 10 mg/L PSMPs) under UV-A radiation exhibited more growth inhibition (nTiO2 + NH2 PSMPs 66%; nTiO2 + COOH PSMPs 50%) than under visible light conditions (nTiO2 + NH2 PSMPs 55%; TiO2 + COOH PSMPs 44%). Independent action modeling indicated that the mixture of nTiO2 with PSMPs (10 mg/L) exhibited an additive effect on the algal growth inhibition under both the light conditions. The photoactive nTiO2 promoted increased production of reactive oxygen species under UV-A exposure, resulting in cellular damage, lipid peroxidation, and impaired photosynthesis. The effects were more pronounced in case of the mixtures where PSMPs added to the oxidative stress. The toxic effects of the binary mixtures of nTiO2 and PSMPs were further confirmed through the field emission electron microscopy, revealing specific morphological abnormalities. This study provides valuable insights into the potential risks associated with the combination of nTiO2 and MPs in marine environments, considering the influence of environmentally relevant light conditions and the test medium.

Immunostimulatory effects of marine algae extracts on in vitro antigen-presenting cell activation and in vivo immune cell recruitment.

Marine algae are photosynthetic eukaryotic organisms that are widely used as sources of food, cosmetics, and drugs. However, their biological and immunological effects on immune cells have not been fully elucidated. To unravel their immunological activity and broaden their application, we generated antigen-presenting cells (APCs), including dendritic cells (DCs) and macrophages, from mouse bone marrow cells and treated them with six different marine algae extracts (MAEs). We evaluated cell viability, activation marker expression, and pro-inflammatory cytokine production by APCs after 2 days of MAE treatment. All six MAEs significantly induced cytokine production of APCs, among which Pyropia yezoensis (PY), Peyssonnelia caulifera (PC), and Meristotheca papulosa (MP) extracts exhibited the strongest effect. Cladophora wrightiana var. minor (CW) extract moderately upregulated cytokine levels but increased the expression of activation markers on DCs. Moreover, PY, PC, MP, Sargassum pectinifera (SP), and Caulerpa okamurae (CO) pre-treated APCs effectively stimulated T-cell proliferation and cytokine production. Furthermore, the mice injected with MAEs exhibited higher cytokine (TNF-α, IL-6, and IL-1ß) production as well as enhanced innate immune cell recruitment capacities (DCs, monocytes, neutrophils, and natural killer cells) in the peritoneal cavity of the mice compared to those of the non-treated mice. Therefore, all MAEs exhibited immunostimulatory potential, with PY, PC, CW, and MP extracts being the most effective in stimulating immune responses and cell activation. To the best of our knowledge, this is the first study to determine the immunomodulatory activities of six MAEs both in vitro and in vivo.

Modulation of Gut Microbiome Community Mitigates Multiple Sclerosis in a Mouse Model: The Promising Role of Palmaria palmata Alga as a Prebiotic.

BACKGROUND: Red marine algae have shown the potential to reduce inflammation, influence microbiota, and provide neuroprotection. OBJECTIVE: To examine the prebiotic properties of Palmaria palmata aqueous extract (Palmaria p.) and its potential as a neuroprotective agent in multiple sclerosis (MS). METHODS: eighty-eight adult Swiss mice were divided into four male and four female groups, including a control group (distilled water), Palmaria p.-treated group (600 mg/kg b.w.), cuprizone (CPZ)-treated group (mixed chow 0.2%), and a group treated with both CPZ and Palmaria p. The experiment continued for seven weeks. CPZ treatment terminated at the end of the 5th week, with half of the mice sacrificed to assess the demyelination stage. To examine the spontaneous recovery, the rest of the mice continued until the end of week seven. Behavioral (grip strength (GS) and open field tests (OFT)), microbiome, and histological assessments for general morphology of corpus callous (CC) were all conducted at the end of week five and week 7. RESULTS: Palmaria p. can potentially protect against CPZ-induced MS with variable degrees in male and female Swiss mice. This protection was demonstrated through three key findings: (1) increased F/B ratio and expansion of the beneficial Lactobacillus, Proteobacteria, and Bactriodia communities. (2) Protection against the decline in GS induced by CPZ and prevented CPZ-induced anxiety in OFT. (3) Preservation of structural integrity. CONCLUSIONS: Because of its propensity to promote microbiota alterations, its antioxidant activity, and its content of -3 fatty acids, Palmaria p. could be a promising option for MS patients and could be beneficial as a potential probiotic for the at-risk groups as a preventive measure against MS.

Sulfated Polysaccharides from Seaweeds: A Promising Strategy for Combatting Viral Diseases-A Review.

The limited availability of treatments for many infectious diseases highlights the need for new treatments, particularly for viral infections. Natural compounds from seaweed are attracting increasing attention for the treatment of various viral diseases, and thousands of novel compounds have been isolated for the development of pharmaceutical products. Seaweed is a rich source of natural bioactive compounds, including polysaccharides. The discovery of algal polysaccharides with antiviral activity has significantly increased in the past few decades. Furthermore, unique polysaccharides isolated from seaweeds, such as carrageenan, alginates, fucoidans, galactans, laminarians, and ulvans, have been shown to act against viral infections. The antiviral mechanisms of these agents are based on their inhibition of DNA or RNA synthesis, viral entry, and viral replication. In this article, we review and provide an inclusive description of the antiviral activities of algal polysaccharides. Additionally, we discuss the challenges and opportunities for developing polysaccharide-based antiviral therapies, including issues related to drug delivery and formulation. Finally, this review highlights the need for further research for fully understanding the potential of seaweed polysaccharides as a source of antiviral agents and for developing effective treatments for viral diseases.

Hoeflea algicola sp. nov. and Hoeflea ulvae sp. nov., isolated from phycosphere of marine algae.

Two Gram-negative, moderately halophilic, and motile rod bacteria, strains G2-23T and J2-29T, showing catalase- and oxidase-positive activities were isolated from species of the marine algae Chondrus and Ulva, respectively. Both strains optimally grew at 30 °C, pH 7.0 and 2% (w/v) NaCl. Both strains contained ubiquinone-10 as the sole isoprenoid quinone. Strain G2-23T contained summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0 and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c/ω6c) as major cellular fatty acids, and phosphatidylethanolamine (PE), phosphatidyl-N-monomethylethanolamine (PME), phosphatidylglycerol (PG), diphosphatidylglycerol and an unidentified phospholipid (PL) as major polar lipids. Strain J2-29T contained summed feature 8, C18 : 1 ω7c 11-methyl and C16 : 0 as major cellular fatty acids and PE, PME, PG and PL as major polar lipids. The genomic DNA G+C contents of strains G2-23T and J2-29T were 59.5 and 62.2 mol%, respectively. Both strains shared 97.9 % 16S rRNA gene sequence similarity, 79.8 % average nucleotide identity (ANI) and 22.8 % digital DNA-DNA hybridization (dDDH) values, indicating that they represent different species. Phylogenetic and phylogenomic analyses by 16S rRNA gene and genome sequences, respectively, revealed that strains G2-23T and J2-29T formed different phylogenic lineages within the genus Hoeflea. ANI and dDDH values between strains G2-23T and J2-29T and other Hoeflea type strains were less than 79.0 and 22.1% and 80.5 and 23.3 %, respectively, suggesting that they represent novel species of the genus Hoeflea. In summary, based on their phenotypic, chemotaxonomic and molecular properties, strains G2-23T and J2-29T represent two different novel species of the genus Hoeflea, for which the names Hoeflea algicola sp. nov. (G2-23T=KACC 22714T=JCM 35548T) and Hoeflea ulvae sp. nov. (J2-29T=KACC 22715T=JCM 35549T), respectively, are proposed.

Sulfated Polysaccharide from Caulerpa racemosa Attenuates the Obesity-Induced Cardiometabolic Syndrome via Regulating the PRMT1-DDAH-ADMA with mTOR-SIRT1-AMPK Pathways and Gut Microbiota Modulation.

Our investigation intended to analyze the effects of sulfated polysaccharides from Caulerpa racemosa (SPCr) in attenuating obesity-induced cardiometabolic syndrome via regulating the protein arginine N-methyltransferase 1-asymmetric dimethylarginine-dimethylarginine dimethylamino-hydrolase (PRMT1-DDAH-ADMA) with the mammalian target of rapamycin-Sirtuin 1-5' AMP-activated protein kinase (mTOR-SIRT1-AMPK) pathways and gut microbiota modulation. This is a follow-up study that used SPs from previous in vitro studies, consisting of 2,3-di-O-methyl-1,4,5-tri-O-acetylarabinitol, 2,3,4,6-tetra-O-methyl-D-mannopyranose, and type B ulvanobiuronicacid 3-sulfate. A total of forty rats were randomly divided into four treatment groups: Group A received a standard diet; Group B was provided with a diet enriched in cholesterol and fat (CFED); and Groups C and D were given the CFED along with ad libitum water, and daily oral supplementation of 65 or 130 mg/kg of body weight (BW) of SPCr, respectively. Group D showed the lowest low-density lipoprotein, triglyceride, total cholesterol, and blood glucose levels, and the highest HDL level compared to the other groups in this study. These results in the group fed high-dose SPCr demonstrated a significant effect compared to the group fed low-dose SPCr (p < 0.0001), as well as in total cholesterol and blood glucose (p < 0.05). Supplementation with SPCr was also observed to have an upregulation effect on peroxisome proliferator-activated receptor gamma coactivator (PGC)-1alpha, interleukin 10, Sirtuin 1, DDAH-II, superoxide dismutase (SOD) cardio, and AMPK, which was also followed by a downregulation of PRMT-1, TNF-α, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, and mTOR. Interestingly, gut microbiota modulation was also observed; feeding the rats with a cholesterol-enriched diet shifted the gut microbiota composition toward the Firmicutes level, lowered the Bacteroidetes level, and increased the Firmicutes level. A dose of 130 mg/kg BW of SPCr is the recommended dose, and investigation still needs to be continued in clinical trials with humans to see its efficacy at an advanced level.