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Settlement induction potential of two red algae, Sahlingia subintegra and Rhodosorus marinus, and one green macroalgae, Ulvella leptochaete was examined to identify potential alternative algal species to improve reliability and reproducibility of Haliotis tuberculata sp. settlement. CCA was used as a positive control. Settlement rates, post-larval survival and growth of Haliotis tuberculata sp. were evaluated for different algal species tested. Results showed that Sahlingia subintegra induced significantly higher settlement rates (58.17 ± 12.71%) compared to CCA, Ulvella leptochaete and Rhodosorus marinus. In all treatments, post-larvae were weekly fed a mix of diatoms (Amphora sp., and Navicula incerta). At four weeks post settlement, post-larval survival rates were significantly higher on CCA and Sahlingia subintegra substrates compared to the other two algal species tested. However, at four and five weeks post settlement there were no significant differences in post-larval shell length and growth rates between CCA and Sahlingia subintegra substrates. These findings suggest that Sahlingia subintegra could be a promising alternative red macroalgae providing settlement cue for abalone hatchery stages, particularly for Haliotis tuberculata sp. and could contribute to improve abalone breeding techniques through the selection of alternative settlement substrates that could be easily managed in abalone farms environments. [ABSTRACT FROM AUTHOR]

The marine red algae Kappaphycus alvarezii (KA), commonly known as cottonii, is a valuable resource with diverse applications. Research has primarily focused on its primary metabolites such as amino acids, proteins, plant hormones etc. Additionally, KA also produces secondary metabolites under stress, some of which exhibit antioxidant and antibacterial properties. This review provides a comprehensive overview of recent in vitro and in vivo research on KA, delving into their therapeutic effects and potential pharmaceutical applications. The study followed a through literature survey in three databases. From the obtained literature, the studies fitting the criteria were reviewed. The study explores the underlying mechanisms behind the algae's diverse characteristics. The results show that KA is a valuable resource for potential therapeutic applications, but a deeper exploration of its various metabolites and rigorous research are necessary for a thorough understanding of its capabilities. [ABSTRACT FROM AUTHOR]

Kappaphycus striatus is one of the carrageenan-producing red algae, and found primarily in tropical and subtropical coastal regions. Its global distribution is mainly in the Philippines, Indonesia, and Malaysia, among other locations. Here, through the high-quality chromosome-level genome sequences and assembly with PacBio HiFi and Hi-C sequencing data, we assembled one genome with a total of 211.46 Mb in size, containing a contig N50 length of 5.04 Mb and a scaffold N50 length of 5.39 Mb. After Hi-C assembly and manual adjustment to the heatmap, we deduced that 199.42 Mb of genomic sequences were anchored to 33 presumed chromosomes, which accounting for 94.31% of the entire genome. One total of 14,596 protein-coding genes and 1,673 non-coding RNAs were identified, and the 100.96 Mb of repetitive sequences accounting for 47.73% of the assembled genome. Our chromosome-level genome assembly data provide valuable references for K. striatus future nursery and breeding, and will be useful for the functional genomics interpretations and evolutionary studies of eukaryotes. [ABSTRACT FROM AUTHOR]

Background: The translocation of photoassimilates is a critical process that links the source and sink in plants, playing an irreplaceable role in maintaining source-sink balance, ensuring plant growth and development, and the formation of yield. Nevertheless, the mechanisms underlying the translocation of photosynthetic products in macroalgae are yet to be fully understood. The purpose of this study is to reveal the role of endocytosis in the translocation of photosynthetic products in the marine red alga Gracilariopsis lemaneiformis by investigating the uptake of photosynthetic products by endocytosis and the impact of endocytic activity on cellular ultrastructure, photosynthesis, and growth. Results: This study discovered that the endocytic activity in non-epidermal cells (NEC, sink cells) of G. lemaneiformis is significantly higher than that in epidermal cells (EC, source cells). NEC is capable of internalizing a greater amount of extracellular carbohydrates, such as sucrose, via endocytosis compared to EC. Further inhibition of endocytic activity in G. lemaneiformis using EIPA resulted in a significant reduction in the content of floridean starch within NEC, whereas the decrease in floridean starch content in EC was not statistically significant. Inhibition of endocytic activity led to an initial decline in photosynthetic efficiency of algal thalli within a few hours, which was followed by an increase as inhibition duration extended, yet the growth rate of the thalli remained substantially suppressed. Conclusions: These findings indicate that endocytosis in G. lemaneiformis plays a role in regulating the cellular uptake of extracellular photoassimilates, which in turn influences the storage substances in sink cells and the overall growth and development of the algae. This study sheds new light on the regulatory mechanisms governing photoassimilate translocation in macroalgae. [ABSTRACT FROM AUTHOR]

Both natural and human-induced stressors cause reef erosion, resulting in reef rubble formation. When consolidated, the rubble can facilitate reef recovery, sparking interest in artificial rubble stabilization as a method for reef restoration. However, our understanding of the natural processes governing coral reef regeneration within rubble beds is limited. This study examines the regeneration processes within ancient rubble frameworks in a Late Triassic carbonate platform. Results show that Late Triassic rubble environments exhibit successional trajectories similar to contemporary rubble environments. Key organisms such as sponges, calcareous red algae, bryozoans, microbes and scleractinian corals, which are instrumental in the consolidation of modern reef rubble, appear to have played comparable roles during the Late Triassic. The similarities between Late Triassic and modern reef rubble consolidation highlight enduring ecological mechanisms important for reef regeneration. This study deepens our understanding of reef dynamics and offers valuable insights for improving current reef restoration strategies, grounded in time-tested natural processes. [ABSTRACT FROM AUTHOR]

Seaweed farming is increasingly recognized as a sustainable marine resource management opportunity, but it also poses socioeconomic and environmental risks that require careful evaluation. This quick scoping review (QSR) examines the current state of knowledge on upscaling seaweed farming through co-location with offshore wind energy production. A total of 240 published records from 2001 to 2022 were analyzed, including studies on general seaweed farming and its integration with offshore wind energy, both of which have shown a significant increase in annual publication rates over time. Geographically, the majority of studies on general seaweed farming were conducted in Asia, while most research on wind-focused integration was carried out in Europe. Differences in cultivated species were evident, with red seaweeds dominating the general literature and brown seaweeds dominating wind-focused studies. Ecosystem service analysis revealed that provisioning services were disproportionately emphasized, while cultural services were underrepresented in wind-focused studies as compared to the general literature. Environmental constraints were the most frequently cited challenges across both datasets, but their nature differed: general literature highlighted issues such as pests, diseases, and epiphytes that reduce farm yield, while wind-focused studies emphasized risks of farms to local species, habitats, and ecosystems. While environmental knowledge gaps were the most frequently cited overall, legal knowledge gaps were predominant in wind-focused studies. These findings underscore the need for more geographically and taxonomically diverse studies on seaweed-wind multi-use, along with further investigation into cultural services in offshore contexts, strategies for mitigating environmental risks, and the development of frameworks for shared governance to advance sustainable ocean development. [ABSTRACT FROM AUTHOR]

This study explores species-specific metabolic responses to different nitrogen-rich formulations in Devaleraea mollis and Palmaria hecatensis, highlighting distinct adaptive strategies. We evaluated the effects of Von Stosch Enrichment (VSE, nitrate-only), F/2 (nitrate-only), and Jack's Special (JS, nitrate and ammonium) on metabolic profiles. D. mollis exhibited elevated energy storage and growth-related metabolites, with JS enhancing creatine production for energy storage and regeneration, alongside increased DNA/RNA synthesis and cell division activity. This suggests D. mollis prioritizes rapid growth and energy demands, supporting broader ecological adaptability. Conversely, P. hecatensis showed higher expression of metabolites linked to amino acid metabolism and protein synthesis, indicating a focus on efficient nitrogen use for protein production, likely advantageous in low-light, high-turbidity conditions. Nitrogen sources significantly influence amino acid metabolism, with JS promoting broader amino acid production and VSE and F/2 stimulating specific metabolites. These species-specific metabolic patterns underscore the flexibility of D. mollis in energy use versus adaptations of P. hecatensis to protein synthesis pathways. These findings highlight species-specific nutrient formulations as essential for optimizing seaweed growth and metabolic traits in aquaculture. [ABSTRACT FROM AUTHOR]

Covering: January to the end of December 2023 This review covers the literature published in 2023 for marine natural products (MNPs), with 582 citations (541 for the period January to December 2023) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, the submerged parts of mangroves and other intertidal plants. The emphasis is on new compounds (1220 in 340 papers for 2023), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. An analysis of the progress in the study of prokaryote involvement in macro-invertebrate MNP production is discussed. [ABSTRACT FROM AUTHOR]

Under physiological conditions, the inflammatory response acts as a biological defense against tissue damage or infection, and is rapidly resolved once the infection is cleared. However, chronic inflammatory diseases, including inflammatory bowel disease (IBD), have become increasingly widespread in the last decades, placing a burden on the quality of life of affected people and on healthcare systems worldwide. Available drug therapies are often ineffective due to the chronic nature of these diseases, and prolonged administration of drugs can result in severe side effects for the patient or a lack of efficacy. In addition, there is the growing problem of bacterial resistance to synthetic antibiotics. Together, these factors have led to a strong research focus on the discovery of natural products capable of treating IBD. Recently, there has been a growing interest in compounds derived from marine sources, mainly algae, due to their bioactive secondary metabolites with anti-inflammatory properties well known in the literature. Based on this evidence, this review aimed to evaluate the anti-inflammatory potential of algae-derived biomolecules in IBD. In particular, interesting species from green algae (e.g., Chlorella vulgaris and Ulva pertusa), brown algae (e.g., Macrocystis pyrifera and Ecklonia cava) and red algae (e.g., Porphyra tenera and Grateloupia turuturu) are included in this review due to their proven anti-inflammatory properties. For this purpose, an extensive literature search was conducted using several databases. The results suggest that both macroalgae and microalgae have remarkable potential for IBD therapy due to the anti-inflammatory and antioxidant activities of their bioactive compounds. However, while the preclinical evidence is encouraging, further and long-term clinical studies are needed to better understand their mechanisms of action in order to determine the true efficacy of marine algae in the treatment of IBD. [ABSTRACT FROM AUTHOR]

During a 2019 Chilean Antarctic Scientific Expedition (ECA 55) studying crustose coralline algae (CCA) diversity on the Antarctic Peninsula, bleaching of these algae was observed for the first time in this region. Here, we present initial findings on the physiological state of bleached and normally pigmented CCA (Clathromorphum sp.) assessed using chlorophyll- a fluorescence induction pulse amplitude modulation. The study site experienced high light exposure and salinity in the water column. Our analyses found that bleached CCA have relatively healthy photophysiology responses but lower photosynthetic efficiency, which could be associated with the low salinities recorded in the study area. However, seasonal monitoring and mesocosm experiments across the southern polar latitudes are urgently required to confirm this hypothesis. [ABSTRACT FROM AUTHOR]

Background/Objective: Colon cancer poses a significant health burden, with current treatments often associated with severe side effects and limited effectiveness for some patients. Natural products are gaining interest as adjuvant therapies, potentially reducing side effects and improving responses to conventional treatments. We previously highlighted the potent antineoplastic effects of organic extracts derived from the Lebanese red algae Jania rubens. This study, investigated the anticancer activities of polysaccharide, protein, and lipid extracts from J. rubens, which may serve as adjuvant therapies to enhance conventional treatments. Methods: we employed colorimetric assays, wound healing assays, and cell cycle analysis to evaluate the anticancer activities of the extracts. The polysaccharide extract was characterized for sulfate content and structure using barium chloride-gelatin and FT-IR methods. Results: All J. rubens extracts exhibited significant anticancer effects, with the polysaccharide extract showing particularly strong cytotoxicity, apoptosis induction, and antiproliferative and anti-migratory activities. Conclusion: These findings confirm that J. rubens is a source of bioactive compounds with anticancer potential. Further investigations are needed to elucidate the molecular pathways targeted by J. rubens extracts in cancer cells. [ABSTRACT FROM AUTHOR]

One year of monthly sampling in some lagoons of the Po Delta and a pond in the Comacchio Valleys helped fill a gap in the knowledge of the primary producers of these degraded environments, focusing on the competition between macrophytes and phytoplankton. Key water column and surface sediment parameters showed a strong association with the different primary producers, explaining the main factors influencing the dominance of one group over the other. Phytoplankton, recorded as Chlorophyll-a and Phaeophytin-a, and Chlorophyceae among the macrophytes, dominated in conditions of high water turbidity and elevated nutrient concentrations. In contrast, macrophytes, particularly Rhodophyceae, their abundance, total biomass, and number of taxa. prevailed in clear, oxygenated waters. Under optimal conditions, sensitive macroalgae and aquatic angiosperms were also present. Additionally, the current list of macroalgal taxa has been updated, highlighting the dominance of some nonindigenous species (NIS) that had not been recorded before the 2000s. Specifically, Gracilaria vermiculophylla and Ulva australis, native to the North West Pacific (Japan, Korea, China, and Vietnam) and to South Australia, as well as the Indo-West Pacific (India, South Africa, Japan, and Korea), respectively, are now the most frequent and abundant taxa in these lagoons. [ABSTRACT FROM AUTHOR]

Inorganic polyphosphate (polyP) is a linear polymer of phosphate that plays various roles in cells, including in phosphate and metal homeostasis. Homologs of the vacuolar transporter chaperone 4 (VTC4), catalyzing polyP synthesis in many eukaryotes, are absent in red algae, which are among the earliest divergent plant lineages. We identified homologs of polyphosphate kinase 1 (PPK1), a conserved polyP synthase in bacteria, in 42 eukaryotic genomes, including 31 species detected in this study and 12 species of red algae. Phylogenetic analysis suggested that most eukaryotic PPK1 homologs originated from horizontal gene transfer from a prokaryote to a plant before the divergence of red algae and Viridiplantae. In red algae, the homologs were fused to a nucleoside diphosphate-linked moiety X (Nudix) hydrolase of the diphosphoinositol polyphosphate phosphohydrolase (DIPP) family. We characterized the fusion protein CmPPK1 in the unicellular red alga Cyanidioschyzon merolae, which has been used in studies on basic features of eukaryotes. In the knockout strain ∆CmPPK1, polyP was undetectable, suggesting a primary role for CmPPK1 in polyP synthesis. In addition, ∆CmPPK1 showed altered metal balance. Mutations in the catalytically important residues of the Nudix hydrolase domain (NHD) either increased or decreased polyP contents. Both high and low polyP NHD mutants were susceptible to phosphate deprivation, indicating that adequate NHD function is necessary for normal phosphate starvation responses. The results reveal the unique features of PPK1 in red algae and promote further investigation of polyP metabolism and functions in red algae and eukaryotic evolution.Key message: The homolog of polyphosphate kinase 1 (PPK1) fused with a nucleoside diphosphate-linked moiety X (Nudix) hydrolase is essential for polyphosphate accumulation and polyphosphate-related functions in the red alga Cyanidioschyzon merolae. [ABSTRACT FROM AUTHOR]

Macroalgae provide key contributions to aquatic ecosystems, including their role as primary producers and the provision of biotopes for marine organisms, fish spawning, and fish nurseries. The aim of this study was to evaluate the feasibility of a micronucleus test and a comet assay in Ceramium tenuicorne, a red macroalga. This alga is widely distributed in marine ecosystems and brackish waters, and is therefore a potential bioindicator of the effects of anthropogenic pollution in these ecosystems. Unfortunately, the two genotoxicity tests evaluated were not suitable for this alga because the nuclei are generally very small (between 2 and 10 µm), are variable in size, and there may be several nuclei in each cell (between 1 and 5 in our observations). However, the present study allowed us to define conditions for observing these algal cells and optimizing the choice of DNA dye (orcein), cell fixation solution (Carnoy's solution), and hydrolysis step (HCl, 1200 mmol/L solution for 1 min). This research allowed us to propose two genotoxicity and cytotoxicity endpoints for assessing chemical effects on the algal cells: counting of nuclei in cortical cell areas, and the frequency of axial cells in mitosis. These two criteria were measured after exposing C. tenuicorne to two reference substances: cadmium chloride and maleic hydrazide, and we highlight the effects from 1 × 10–5 M of CdCl2 and 5 × 10–5 M of maleic hydrazide. [ABSTRACT FROM AUTHOR]

Phycobilisomes (PBS) are the major photosynthetic light-harvesting complexes in cyanobacteria and red algae. While the structures of PBS have been determined in atomic resolutions, how PBS are attached to the reaction centers of photosystems remains less clear. Here, we report that a linker protein (LcpA) is required for the attachment of PBS to photosystem II (PSII) in the cyanobacterium Synechococcus sp. PCC 7002. We also report that the PB-loop of PBS, which is located within the α-APC domain of ApcE, is required for the attachment of PBS to PSII. Deletion of either PB-loop or the gene A0913 led to a decreased rate of photoautotrophic growth under illumination of green light, which is preferentially absorbed by PBS. A double mutant lacking the PB-loop and A0913 (ΔPBL-0913) showed a complete inhibition of O2 evolution under the 590 nm light and could not grow under green light illumination. While assembled PBS could be isolated from ΔPBL-0913, the energy transfer from its PBS to PSII was blocked as measured by fluorescence induction. Photobleaching with intact cells showed that the PBS movement speed in ΔPBL-0913 was 2.5 times as fast as that of the wild type, suggesting that association of its PBS with thylakoids was weakened significantly. The pull-down and coimmunoprecipitation results showed that the LcpA interacts with the CP47 subunit of PSII through its N-terminal region and interacts with ApcB of PBS through its C-terminal α-helix motif. Our results provide insights into the molecular mechanism of PBS-PSII association and shed light on excitation energy transfer from PBS to PSII. [ABSTRACT FROM AUTHOR]

Compared with green plants, brown algae are characterized by their ability to accumulate iodine, contributing to their ecological adaptability in high-iodide coastal environments. Vanadium-dependent haloperoxidase (V-HPO) is the key enzyme for iodine synthesis. Despite its significance, the evolutionary origin of V-HPO genes remains underexplored. This study investigates the genomic and evolutionary dynamics of V-HPOs in brown algae, focusing on Laminariales species, particularly Saccharina japonica. Genomic analyses revealed the extensive expansion of the V-HPO gene family in brown algae, with 88 V-HPOs identified in S. japonica, surpassing the number in red algae. Phylogenetic analysis demonstrated distinct evolutionary divergence between brown and red algal V-HPOs, with the brown algal clade closely related to bacterial V-HPOs. These findings suggest horizontal gene transfer (HGT) played a key role in acquiring V-HPO genes, particularly from Acidobacteriota, a bacterial phylum known for genomic plasticity. Additionally, enriched active transposable elements were identified around V-HPO genomic clusters, highlighting their role in tandem gene duplications and rapid HGT processes. Expression profiling further revealed dynamic regulation of V-HPOs in response to environmental conditions. This study provides new insights into how HGT has driven kelp genomic adaptations and enhances understanding of marine ecological success and evolutionary processes. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the laboratory cultivation of Chondracanthus acicularis, focusing on key environmental parameters such as nutrient levels and light exposure. The results provide insights into the optimal growth conditions and biochemical composition of C. acicularis, which are crucial for its sustainable exploitation in industrial applications. Significant differences in the relative growth rate (RGR) and productivity (Y) were found between the different treatments. Seaweed grown on Provasoli (PES) Medium with white LED light and red LED light showed the best growth rates. Negative growth was observed in treatments with Nutribloom plus®, and blue LED light. The proximate composition analysis revealed a high moisture content across all treatments, with significant differences in ash and organic matter content between the treatments. The use of LED light played a crucial role in optimizing growth by influencing photosynthetic efficiency and pigment production. The proximate composition varied significantly between treatments, especially ash and organic matter. Light and nutrient conditions also influenced pigmentation and colour characteristics, with significant changes in phycoerythrin, phycocyanin, and chlorophyll concentration. PES treatments consistently showed the highest colour variation. These findings highlight the influence of environmental conditions on seaweed growth, productivity, pigmentation, and proximate composition, and provide valuable insights for optimized cultivation strategies. [ABSTRACT FROM AUTHOR]

Archaeplastida , a group of photosynthetic organisms with primary plastids, consists of green algae (plus land plants), red algae, and glaucophytes. In contrast to green and red algae, information on lipids and lipid biosynthesis is still incomplete in the glaucophytes. The chloroplast is the site of photosynthesis and fatty acid synthesis in all photosynthetic organisms known to date. However, the genomic data of the glaucophyte Cyanophora paradoxa indicated the lack of acetyl-CoA carboxylase and most components of fatty acid synthase in the chloroplast. Instead, multifunctional fatty acid synthase and acetyl-CoA carboxylase are likely to reside in the cytosol. To examine this hypothesis, we measured fatty acid synthesis in isolated chloroplasts and whole cells using stable isotope labeling. The chloroplasts had very low fatty acid synthesis activity, if any. Most processes of fatty acid synthesis, including elongation and desaturation, must be performed within the cytosol, and the fatty acids imported into the chloroplasts are assembled into the chloroplast lipids by the enzymes common to other algae and plants. Cyanophora paradoxa is a rare organism in which fatty acid synthesis and photosynthesis are not tightly linked. This could question the common origin of these two biosynthetic processes in Archaeplastida. [ABSTRACT FROM AUTHOR]

This study presents a detailed morphology and taxonomic study of Polysiphonia subtilissima collected from Abdul Rehman Goth, Karachi coast, Pakistan. Polysiphonia is a filamentous heterotrichous red algae, characterized by its branching structures and attachment mechanisms. P. subtilissima is notable for its broad salinity tolerance and wide distribution across marine and freshwater ecosystems. This research provides an in-depth examination of the internal and external structures of P. subtilissima, contributing to its systematic study and documenting its first recorded occurrence in Pakistani coastal areas, bordering the northern Arabian Sea. The findings enhance the understanding of the species taxonomy and its ecological role in the region. [ABSTRACT FROM AUTHOR]

Simple Summary: The red macroalgae Acanthophora spicifera (spiny seaweed) is a naturalized alien species at La Paz Bay and appears to tolerate areas with human activity. However, before this study, we were unaware of the type and quantity of hydrozoan epibiont growing on this alga. Therefore, this study aims to examine the community structure of hydrozoan epibionts of A. spicifera in warm and cold seasons. We recorded eleven hydrozoans, of which there are more in summer. This study provides a detailed analysis of the community of hydrozoan epibionts of Acanthophora spicifera in La Paz Bay, Baja California Sur. The investigation was carried out in two season periods, corresponding to the warm and cold seasons on the pier of the Autonomous University of Baja California Sur (UABCS) Pichilingue research station. The percentage of epibiont coverage was calculated and analyzed. The average length of the thalli was 7.8 ± 4.6 cm. Eleven taxa of hydrozoans were recorded; the hydrozoan Obelia cf. dichotoma had the highest coverage percentage, and in summer, there was a higher taxa richness. It is recommended to monitor this macroalga and its epibionts for its wide distribution in the bay, although in UABCS, Pichilingue Pier has not seen epibionts that threaten biological diversity. [ABSTRACT FROM AUTHOR]

To evaluate the nutritional value and development potential of Pterocladiella capillacea in the marine environment of Naozhou Island, Zhanjiang, this study conducted species classification and identification, followed by an analysis of key nutritional components. The combination of morphological and molecular results confirmed the identification of the collected samples as P. capillacea. Further analysis showed that P. capillacea in Zhanjiang had a moisture content of 74.9% and a protein content of 24%. In comparison, the fat (0.4%) and carbohydrate (15.4%) contents were relatively low, with moderate ash (14.3%) and crude fiber (9.1%) content. It contains a diverse range of fatty acids, with saturated fatty acids accounting for 51.82% and unsaturated fatty acids accounting for 48.18% of the total. The amino acid composition was also diverse, with essential amino acids comprising 31.58% and flavor-enhancing amino acids constituting 54.85%. The minerals contained four major elements and four trace elements, while heavy metal levels were within safety limits, ensuring their edibility. In conclusion, P. capillacea is a high-protein, low-fat economic seaweed with a favorable amino acid and fatty acid composition, rich in minerals, and with significant nutritional and developmental potential. This study provides important data to support future research and utilization of this seaweed. [ABSTRACT FROM AUTHOR]

The state of Michigan is 253,800 km2 in size with abundant freshwater habitats, including lakes, streams, ponds, and rivers that are ideal for freshwater red algae from the order Batrachospermales. In addition, there are numerous herbarium records, but approximately 60% are more than 20 years old. Recent collections have been from a small geographic area and only a handful of specimens have associated DNA sequences that are often needed for accurate species identification. We surveyed broadly in the Upper and Lower Peninsula, revisiting previously sampled sites and exploring new localities. Freshwater red algae were collected from 19 sites that varied from small streams, rivers, and lake inlet/outlets with a corresponding range in water temperature, pH, and conductivity. Four genera were collected, Batrachospermum, Paludicola, Sheathia, and Virescentia, with species identifications verified with rbcL gene sequencing. The genus Sheathia was the most abundant (15 sites) and represented by two species, S. grandis and S. involuta. At seven sites, we found Batrachospermum gelatinosum, whereas Paludicola communis and Virescentia viride-americana were each collected once. Although these four genera have been previously known from the state, this study provided the first rbcL sequence for B. gelatinosum and P. communis in Michigan. At one location, we confirmed the presence of Virescentia viride-americana 30 years after it had first been collected, and likewise, we confirmed B. gelatinosum at another site 27 years later. Sheathia grandis was recently described from only two locations in nearby states. This study was the first report in Michigan and added considerably to the number of known locations. This research has yielded new records, species identification with DNA sequence, and expanded habitat information. [ABSTRACT FROM AUTHOR]

This study explores the potential of using natural textile packaging infused with algae-based coatings as an eco-friendly alternative to traditional plastic packaging for extending fruit shelf life. Traditional plastic packaging is known to release harmful chemicals into both food and the environment, which underscores the need for safer, more sustainable alternatives. This study investigates algae from three distinct groups—green, red, and brown algae—renowned for their rich bioactive compounds that exhibit natural preservative properties. Algae powders were prepared via immersion in purified water, boiling, and mixing with gum arabic to form a gelatinous coating solution. The algae coating was applied to knitted fabric, which was then crafted into bags for storing fruits such as tomatoes and apples. Over 21 days, the texture, weight loss, and juice content of the fruits stored in algae-coated bags were monitored and compared to those stored in uncoated packaging. The results showed that fruits in algae-coated packaging demonstrated significantly less weight loss and retained better texture. In terms of weight, the combination of red, green, and brown algae-coated packaging demonstrated the lowest reduction in weight for tomatoes (4.2%) and apples (3.8%) after 21 days, outperforming uncoated packaging, which exhibited reductions of 11.2% and 10.8%, respectively. These findings support the potential of algae-coated textile packaging to reduce reliance on conventional plastics while maintaining fruit quality during storage. [ABSTRACT FROM AUTHOR]

During growth progress of algae, the algal–bacterial interactions play a major role in growth of algal. It is critical to understand the mechanisms of phycosphere, regarding their distribution under different environments. Therefore, here we examined the P. purpureum growth and its associated unique microbial community structures under different nitrogen sources at different days. The results revealed that KNO3 meritoriously increased the P. purpureum growth by 11.484 g/L, cellular cell bond polysaccharides by 4.03 mg/mL, soluble exopolysaccharides by 2.881 mg/mL as compared to NH4NO3 and NH4-CL sources. Furthermore, the relationship of the α-diversity index of microbial communities was high under the ammonia source during growth process which was observed at 16th day. The results of UniFrac statistical distance between or within the samples showed the significantly higher on the 16th day of growth stage under ammonia sources. The main bacterial families (Oxyphotobacteria, Bacteroidia, Alphaproteobacteria, Chloroplast, Cytophagales, and Phycisphaerales) were diverse significantly and strongly associated with P. purpureum over the different stages of growth, which contribute to their relative abundance increased substantially (78%). The unique operational taxonomic units (OTUs) were shared among Proteobacterai, Becteroidetes, and Firmicutes are most abundant phylum, with shares of 65%, at the genus level, Bacteroides, P. purpureum, and Algorisphages (20%) occupied the OTUs occurrence frequency. The Venn diagram shows that during growth, ammonia source on day 16 has the highest number of unique OTUs (3566), indicating the high degree of microbial diversity of the P. purpureum. These results allowed to identify the underlying mechanisms for these relationships of algae bacteria consortia, which is useful for the sustainable culture and production of high valuable products. [ABSTRACT FROM AUTHOR]

Marine caves, often overlooked hotspots of biodiversity, provide unique habitats for specialized species. Located on the Mediterranean coast, Rosh HaNiqra is a midlittoral cave renowned for its vibrant epilithic algal community. In the study reported here, we explored the light environment, algal composition, and ecological dynamics of the Rosh HaNiqra cave. Light measurements revealed that illumination in the cave ranged from 0.5 to 2.5% of the sunlight recorded at the mouth of the cave, with variations across seasons and times of day, peaking during summer, and an increase in red wavelengths towards sunset. Biodiversity assessments, including rbcL gene sequencing studies, identified Hildenbrandia rubra (red alga) as the principal alga, together with Blidingia dawsonii (green alga), cyanobacteria, and mosses, forming a "Balcony of Colors". The cave's conditions were found to be most favorable for H. rubra in the autumn through early winter, when the cave provides a critical refuge where this alga thrives in stable, low-light conditions, demonstrating high photosynthetic efficiency even in reduced light. Our study of algal distribution showed seasonal fluctuations, with peak coverage during warmer months and a decline in winter. This study not only deepens our understanding of Rosh HaNiqra's cave ecosystem but also provides an essential baseline for future ecological and conservation research in marine caves. [ABSTRACT FROM AUTHOR]

The red seaweed Solieria filiformis is a source of nutrients, active biomolecules, and the iota(ι)-carrageenan hydrocolloid. In Brazil, it is found in natural stock; however, the sustainable biomass production of this seaweed species in the sea has not been reported. The S. filiformis cultivation was evaluated at Flecheiras Beach, on the coast of Ceara State in Northeast Brazil, using Long-line with Vertical Rope Structures (LVRS) and Colonized Modules (CM) methods during the rainy and dry seasons. The environmental parameters of the cultivation site, the daily growth rates (DGR) at 30, 45, and 60 days after planting, the biomass density, and the ι-carrageenan extracted were assessed. Local environmental conditions supported seaweed growth in both seasons. However, the highest DGR (6.1%) was recorded 30 days after planting during the dry season using LVRS. The highest seaweed biomass density was 53 kg ws module−1 using CM method. The highest ι-carrageenan yields (48.3% and 53.1%) were obtained from the biomasses produced in the dry season, using LVRS and CM methods, respectively. The mean sulfate content of the ι-carrageenan extracted was 26.8 ± 1.9%, a relevant feature of their physicochemical properties and biological activities. [ABSTRACT FROM AUTHOR]

In tropical ecosystems worldwide, benthic marine algae are important primary producers and habitat providers for many juvenile fish and invertebrate species. Calcified species are known to provide structural support to their respective communities, thus enhancing the overall system’s productivity. In the Republic of the Maldives, algae are an important yet currently poorly studied biological resource. We reviewed the literature around algal diversity and distribution across Maldivian atolls and compiled an extensive and updated taxonomic list. The list contains 353 species, of which 31 are Cyanobacteria, 26 Phaeophyceae, 109 Chlorophyta, and 187 Rhodophyta. Algal collections have been reported from 12 out of 20 atolls, and these mostly occurred during 20th century expeditions. The taxonomic status of 110 species has changed since first reported. While several species have been documented from the country, identifications have thus far almost solely relied on morphological assessments. Many of the reported algal groups require molecular confirmation. This suggests that benthic algal diversity from the Maldives is likely an underestimate. Since anthropogenic activities can significantly alter algal community dynamics, a baseline understanding of algal diversity is necessary to determine how such shifts affect the ecosystem as a whole, thus underpinning future management and conservation efforts. [ABSTRACT FROM AUTHOR]

To understand pathogenic mechanisms and suggest molecular biomarker candidates for the disease status of edible red algae, Pyropia, we analyzed relationships between disease symptom severity, changes in microbial communities, and the metabolic dysregulation of the red algae with 16S and 18S ribosomal RNA gene amplicon sequencing and mass spectrometry-based metabolomics. Our observations of disease symptoms and microbial communities indicated that Pythium was the major pathogen. As the disease progressed, the prokaryotic diversity and composition of the microbial communities were clearly distinct from diseased thalli compared with healthy and weakly diseased thalli. The results of the microbial correlation network analysis showed the co-occurrence of known pathogenic microbes in the diseased thalli. Similarly, the results of the metabolomic analysis showed that the relative abundance of annotated metabolites differed in the diseased thalli compared with the healthy and weakly diseased thalli. In particular, three purine metabolism-related metabolites—hypoxanthine, guanine, and inosine—increased significantly in the diseased thalli. All the affected metabolites in abundance regulation, including the three metabolites, are known to be related to biotic stress and defense mechanisms. This study contributes to filling the gaps in research on molecular and microbial events, especially the links between pathogenic and non-pathogenic microbes, metabolites, and symptom severity in Pyropia. Additionally, the results indicate that the observed prokaryotic diversity reduction and co-occurrence of the known microbial pathogens are new non-target indicators that could be beneficial in cases where no known pathogens indicate pathogenicity. Dysregulated purine metabolism-related metabolites and other stress- and defense-related metabolites are potential molecular indicators of disease status of Pyropia. [ABSTRACT FROM AUTHOR]

Haptophyta represents a major taxonomic group, with plastids derived from the primary plastids of red algae. Here, we elucidated the cryoelectron microscopy structure of the photosystem I-light-harvesting complex I (PSI-LHCI) supercomplex from the haptophyte Isochrysis galbana. The PSI core comprises 12 subunits, which have evolved differently from red algae and cryptophytes by losing the PsaO subunit while incorporating the PsaK subunit, which is absent in diatoms and dinoflagellates. The PSI core is encircled by 22 fucoxanthin-chlorophyll a/c-binding light-harvesting antenna proteins (iFCPIs) that form a trilayered antenna arrangement. Moreover, a pigment-binding subunit, LiFP, which has not been identified in any other previously characterized PSI-LHCI supercomplexes, was determined in I. galbana PSI-iFCPI, presumably facilitating the interactions and energy transfer between peripheral iFCPIs and the PSI core. Calculation of excitation energy transfer rates by computational simulations revealed that the intricate pigment network formed within PSI-iFCPI ensures efficient transfer of excitation energy. Overall, our study provides a solid structural foundation for understanding the light-harvesting and energy transfer mechanisms in haptophyte PSI-iFCPI and provides insights into the evolution and structural variations of red-lineage PSI-LHCIs. [ABSTRACT FROM AUTHOR]

Cyanobacterial photosynthesis (to produce ATP and NADPH) might have played a pivotal role in the endosymbiotic evolution to chloroplast. However, rather than meeting the ATP requirements of the host cell, the modern-day land plant chloroplasts are suggested to utilize photosynthesized ATP predominantly for carbon assimilation. This is further highlighted by the fact that the plastidic ADP/ATP carrier translocases from land plants preferentially import ATP. Here, we investigate the preferences of plastidic ADP/ATP carrier translocases from key lineages of photosynthetic eukaryotes including red algae, glaucophytes, and land plants. Particularly, we observe that the cyanobacterial endosymbionts expressing plastidic ADP/ATP carrier translocases from red algae and glaucophyte are able to export ATP and support ATP dependent endosymbiosis, whereas those expressing ADP/ATP carrier translocases from land plants preferentially import ATP and are unable to support ATP dependent endosymbiosis. These data are consistent with a scenario where the ancestral plastids may have exported ATP to support the bioenergetic functions of the host cell. Cyanobacterial bioenergetics may have driven chloroplast evolution. Here, the authors show that cyanobacterial endosymbionts expressing plastidic ADP/ATP carrier translocases from red algae and glaucophyte support photosynthesis-driven bioenergetic endosymbiosis, but not those from green land plants. [ABSTRACT FROM AUTHOR]

Lithothamnionmirabile is currently considered a heterotypic synonym of L. muelleri. Three of the 14 specimens and additional fragments comprising the holotype of L. mirabile were selected for DNA sequencing as they best matched the protologue. The three 263-base pair rbcL sequences were distinct from each other, and were classified in the order Hapalidiales, but none were resolved in Lithothamnion. One sequenced specimen belongs in Roseolithon and was selected as the lectotype; thus we propose R. mirabile (Foslie) comb. nov. Another sequenced specimen groups with Phymatolithopsis and the third is well resolved in an undescribed genus of Hapalidiales sister to Boreolithothamnion. [ABSTRACT FROM AUTHOR]

The genus Gelidium is a representative element of the Mexican Tropical Pacific. The recent use of molecular tools has allowed us to resolve the taxonomic problems of some species and to increase the knowledge regarding this group of red algae in the region. The present study aimed to evaluate specimens collected in the southern Mexican Tropical Pacific using molecular markers and morphological characters. Samples were collected from four locations along the coast of Oaxaca state. They were characterised morphologically and molecularly using rbcL and COI–5P. Phylogenetic analysis classified the examined specimens into three independent clades, representing taxonomic entities different from what has been described previously for the genus. With the support of morphological data and genetic distances, we propose three new species for the Mexican Tropical Pacific: Gelidium dawsonii sp. nov., Gelidium longisporophyllum sp. nov., and Gelidium rubruparvum sp. nov. Some of the distinct characteristics of these species are based on little size of G. rubruparvum, the branching pattern of G. longisporophyllum and G. dawsonii, the number of layers of medullary cells in G. dawsonii and G. rubruparvum, and the tetrasporangial sorus in G. longisporophyllum. We also highlight the relationship between Asian and Mexican species and the value of using different tools in the evaluation of the taxonomic status of the genus Gelidium. [ABSTRACT FROM AUTHOR]

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

Neopyropia yezoensis, a marine red algae species, has significant economic and ecological value. However, phosphorus (P) deficiency has emerged as a growing concern in many cultivation regions, negatively impacting its growth. To adapt to P deficiency, algae have evolved various strategies, including using dissolved organic phosphorus (DOP) sources to sustain growth. Despite its prevalence as a form of DOP, the utilization mechanism of glucose-6-phosphate (G6P) by N. yezoensis remains unclear. In this study, the physiological and transcriptional responses of N. yezoensis to P deficiency and G6P supplementation were examined. The results demonstrated that prolonged P deficiency significantly inhibited the growth of N. yezoensis and had a negative impact on physiological indicators such as photosynthetic pigments and antioxidant enzyme activity. However, G6P treatment gradually alleviated these adverse effects over time. Both P deficiency and G6P treatment were associated with increased expression of genes involved in signal transduction and P starvation responses while concurrently downregulating genes related to photosynthesis and antioxidant defenses. In contrast, the suppression of gene expression was less significant under G6P treatment. This study elucidates the adaptive strategies of N. yezoensis in response to P deficiency and clarifies the regulatory pathways involved in G6P utilization, providing novel insights into its P nutrient acquisition and metabolic regulation. [ABSTRACT FROM AUTHOR]

The freshwater red alga Batrachospermum gelatinosum has a well‐documented distribution spanning historically glaciated and unglaciated eastern North America. This alga has no known desiccation‐resistant propagule; thus, long‐distance dispersal events are likely rare. We predicted strong genetic structure among drainage basins and admixture among sites within basins. We predicted greater genetic diversity at lower latitude sites because they likely serve as refugia and the origin of northward, post‐Pleistocene range expansion. We used 10 microsatellite loci to investigate genetic diversity from 311 gametophytes from 18 sites in five major drainage basins: South Atlantic Gulf, Mid‐Atlantic, Ohio River, Great Lakes, and Northeast. Our data showed strong genetic partitioning among drainage basins and among sites within basins, yet no isolation by distance was detected. Genetic diversity varied widely among sites and was not strictly related to latitude as predicted. The results from B. gelatinosum provide strong support that each stream site contributes to the unique genetic variation within the species, potentially due to limited dispersal and the prevailing reproductive mode of intragametophytic selfing. Simulations of migration suggested post‐Pleistocene dispersal from the Mid‐Atlantic. Batrachospermum gelatinosum potentially persisted in refugia that were just south of the ice margins rather than in the southernmost part of its range. Research of other taxa with similar ranges could determine whether these results are generally applicable for freshwater red algae. Nevertheless, these results from B. gelatinosum add to the growing literature focused on the patterns and genetic consequences of post‐Pleistocene range expansion by eastern North American biota. [ABSTRACT FROM AUTHOR]

Shell infiltration of free-living conchocelis of the three commercial Pyropia species (P. yezoensis, P. seriata, and P. dentata) were examined in various conditions of temperatures (20-25°C), light intensities (1, 10, 40, and 80 μmol photons m-2 s-1), conchocelis quantities (100, 150, 200, 250, and 300 mg) and sizes (108, 209, 324, 411, and 519 μm). The optimal shell infiltration conditions were 20°C and 40 μmol photons m-2 s-1 in all species. The infiltration densities were 44.81-146.15 conchocelis cm-2 for P. yezoensis, 51.40-190.49 conchocelis cm-2 for P. seriata, and 22.24-92.49 conchocelis cm-2 for P. dentata. Inefficient shell infiltration was observed with the different conchocelis quantities from 100 to 300 mg. A positive corelationship was observed between shell infiltration density and the amount of conchocelis. The optimal blending time for maximizing infiltration density was 40 s for P. yezoensis and P. seriata and 25 s for P. dentata. This blending time correlated with a cell count of 5-7 cells. Total conchocelis lengths of 5-7 cells were approximately 300 μm for P. yezoensis and P. seriata (with cell size of about 45 μm) and approximately 400 μm for P. dentata (with a cell size of about 65 μm). These results suggest that, to achieve optimal shell infiltration density for P. dentata, the blending time should be reduced by half, and the amount of conchocelis should be increased twofold, making it comparable to the other two Pyropia species. [ABSTRACT FROM AUTHOR]

The interplay between calcium signaling and reactive oxygen species (ROS) production is important in many cellular activities, yet its involvement in biological processes in red algae is mostly not studied. Fertilization in red algae is unique, and while it is known that ROS is a necessary signal, its producing and interplay with calcium and calcium-dependent protein kinases (CDPKs) is unknown. Through experimental assays, we visualized calcium influx and ROS accumulation during fertilization in the red alga Bostrychia moritziana. Through transcriptomics, five CDPK family genes were identi- fied in B. moritziana, with structural analysis revealing variation in these homologs. Protein structure prediction shows similarities and differences in CDPK structures, likely reflecting their different roles in cellular processes. The regulatory role of CDPKs in ROS production was confirmed by the increased expression of CDPKs genes during fertilization. The inhibition experiments showed that reciprocal positive feedback between CDPK expression and ROS production, emphasizing the intricate regulatory mechanisms underlying calcium-dependent signaling pathways. The fertilization process of B. moritziana could also be an excellent model to study the role of CDPKs in the downstream signaling pathways of the interaction of calcium and ROS signaling. [ABSTRACT FROM AUTHOR]

Carrageenans are polysaccharides from red algae which are widely used as food additives and in other applications. Their structure is often described by different disaccharide repeating units, although it was already demonstrated that reality is more complex. In many studies, commercial carrageenans were used to establish structure function relationships, but a structural and compositional analysis was rarely conducted. Therefore, the aim of our study was to systematically and comprehensively characterize a broad collection of commercial carrageenans with different specifications from different manufacturers. For a more detailed characterization, an analytical approach based on partial enzymatic hydrolysis in combination with HPLC–MS and HPSEC-RI was developed and applied. Furthermore, rheology was used to gain detailed insights into the functionality of selected samples. Our results demonstrate that significant structural variation can be observed for commercial carrageenans. The samples contained different cations and the carrageenan type specified by the manufacturer did not always represent the structure of the corresponding polysaccharides. This was especially true for λ-carrageenans: Of the six commercial samples analyzed, none contained structural elements from the λ-type. Instead, the corresponding carrageenans contained κ-, ι- and ν-units. The application of the developed enzymatic-chromatographic approach showed that different hybrid carrageenans are present. In addition, the rheological analysis of the commercial carrageenan samples showed clear differences in the gelling properties upon calcium addition which could influence their behavior in different applications. Our results demonstrate that before an investigation of structure–function relationships, commercial carrageenan samples should be analyzed for their structure and composition. We also showed that the enzymatic-chromatographic approach described in this study is well suited for this purpose. [ABSTRACT FROM AUTHOR]

This research aims to develop an innovative solution to reduce the problem of plastic waste by designing and optimizing an edible film formula using milkfish bone gelatin and red algae as edible film composite materials. Milkfish gelatin was chosen because it can form an elastic and strong film, while red algae provides softness and resistance to microorganism activity. This research consists of several stages, including gelatin extraction, carrageenan extraction from Eucheuma cottonii and formulating composite edible films. Based on the results of the analysis carried out, the average yield of milkfish bone gelatin was 10.55% and the average yield of E.cottonii carrageenan extract was 20.62%. The thickness of composite edible film ranges from 0.15-0.25 mm, the highest tensile strength value is 6.3 MPa and the lowest is 3 MPa, and the highest percent elongation of edible film is 80% and the lowest is 36.67%. The values obtained are in accordance with the JIS 2-1707 (Japan Industrial Standard) (1946) standard. [ABSTRACT FROM AUTHOR]

Carrageenan, an extract from red seaweed (Rhodophyta), has many uses in cosmetics, and this literature review delves into them all. Due to its superior gelling, thickening, and stabilizing properties, carrageenan, a polysaccharide with a wide range of chemical structures, has been utilized in various industries throughout history. In recent years, the cosmetics industry has shown growing interest in harnessing the potential of carrageenan, driven by the increasing demand for natural and sustainable ingredients. This review provides a comprehensive examination of the botanical background, types of carrageenan, and the most effective extraction methods for obtaining the key bioactive compounds that enhance its functionality in cosmetic formulations. The functional properties of carrageenan in cosmetics are discussed in depth, including its gelling and thickening capabilities, moisturizing effects, and stability enhancement. Additionally, its biological activities, such as antioxidant and antiinflammatory properties, contribute to its appeal as a valuable ingredient in skincare products. Formulation considerations, including compatibility with a wide range of cosmetic ingredients and optimal concentrations, are explored to facilitate the development of effective products. The review also addresses the incorporation of carrageenan into cosmetic formulations, along with safety and regulatory aspects, ensuring a comprehensive understanding of the product's conformity with industry standards. In conclusion, the review provides an overview of current challenges, potential future research directions, and case studies showcasing the incorporation of carrageenan into cosmetic products. This review aims to serve as a valuable resource for researchers, formulators, and industry professionals interested in the innovative use of carrageenan in the evolving landscape of cosmetic science by synthesizing existing knowledge and identifying gaps in the current scientific literature. [ABSTRACT FROM AUTHOR]

Simple Summary: Mexico ranked among the ten countries with the highest GHG production in 2017, reporting a contribution of 1.68% of global emissions; in this sense, it has committed to reducing GHG emissions by up to 22% by 2030 (Government of Mexico, 2015). The First National Tier 2 Inventory of methane emissions from enteric fermentation of cattle in Mexico, registering 2039.21 ± 205.5 Gg of CH4 per year. Currently, most studies on livestock and climate change in Latin America are focused on quantifying CH4 emission volumes, determining emission factors, and calculating national inventories; few studies focus on the development of mitigation strategies; many positive attributes of macroalgae have been identified concerning contributing nutrients such as protein and also in the energy metabolism of animals of livestock interest. Some in vitro studies have shown that red and brown macroalgae can reduce CH4 production by controlling the populations of methanogenic bacteria in the rumen. The impact of macroalgae species on rumen function remains largely unexplored. This present study aimed to identify the biocompounds of the three types of marine macroalgae described: Macrocystis pyrifera (Brown), Ulva spp. (Lettuce), Mazzaella spp. (Red) and their effect on species-specific modulations of the rumen microbiome. The macroalgae were characterized using GC-MS. Twelve Rambouillet lambs were randomly assigned to one of four experimental diets (n = 3 per treatment): (a) control diet (CD); (b) CD + 5 g of Red algae; (c) CD + 5 g of Brown algae; and (d) CD + 5 g of Lettuce algae. After the lambs ended their fattening phase, they donated ruminal fluid for DNA extraction and 16S rRNA gene V3 amplicon sequencing. Results: The tagged 16S rRNA amplicon sequencing and statistical analysis revealed that the dominant ruminal bacteria shared by all four sample groups belonged to phyla Firmicutes and Bacteroidota. However, the relative abundance of these bacterial groups was markedly affected by diet composition. In animals fed with macroalgae, the fibrinolytic and cellulolytic bacteria Selenomonas was found in the highest abundance. The diversity in chemical composition among macroalgae species introduces a range of bioactive compounds, particularly VOCs like anethole, beta-himachalene, and 4-ethylphenol, which demonstrate antimicrobial and fermentation-modulating properties. [ABSTRACT FROM AUTHOR]

Environmental racism may be among the explanations for why we are facing the worst socioenvironmental crisis in the history of humanity, led by a state of climate emergency that could result in an ecocidal genocide of planetary dimensions. Unfoldings of environmental racism even reach towards nature when it is considered subject of rights. Among the marine ecosystems less considered in these discussions are rhodolith beds—reef habitats of red coralline algae, also called maerl beds. When dealing with the feasibility of oil exploration in the Amazon mouth region, an area dominated by extensive rhodolith beds, the Brazilian Association of Petroleum Geologists broadcast live a geologist quoted as saying (transcript follows) '... what there is (at the mouth of the Amazon) are coralline algae called rhodoliths, which are common, anywhere in Brazil, and are things, errrrr (with hand gestures and facial expression with negative or pejorative sense), ugly like that, they're not nice at all, (...) and even the rhodolith reefs are dead reefs, dead'. As a result, now, the region is facing the real possibility of extensive oil exploitation. This opinion of a limited aesthetical perspective of which nature is important demands urgent public recognition. Policies that foster rhodolith bed conservation needs, explaining their wealth of valuable contributions to society, must be introduced in formal education, dialoguing with children, young people and adults. Multilateral United Nation forums, during the Ocean Decade, can provide ways to speed up this process, combating different forms of environmental racism and speciesism, buying some time and creating opportunities to establish rhodolith bed conservation as a natural world heritage. [ABSTRACT FROM AUTHOR]

Nitrogen is essential for plants' growth, yield, and crop quality, and its deficiency limits food production worldwide. In addition, excessive fertilization and inefficient use of N can increase production costs and cause environmental problems. A possible solution to this problem is the application of biofertilizers, which improve N assimilation and increase biomass and yield. Therefore, the objective of this research was to evaluate the impact of the application of a combination of green and red algae (Ulva lactuca and Solieria spp.), Rhizobium sp., Trichoderma asperellum, and the combination of the above three biofertilizers on N assimilation. A completely randomized design was performed, with 10 plants per treatment and five treatments: T1 = control; T2 = algal extracts; T3 = Rhizobium sp.; T4 = T. asperellum; T5 = T2 + T3 + T4. Our analyses showed that the biofertilizers' application was better than the control. The application of Rhizobium sp. had the best performance amongst all of the biofertilizers, with the highest nitrate reductase activity in maize leaves, which enhanced photosynthesis, increasing biomass and yield. The use of Rhizobium sp. showed increases in biomass (13.4%) and yield (11.82%) compared to the control. This research shows that biofertilizers can be a key component for sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

A red alga named Rhodymenia intricata was explored, and the extraction technology and antioxidant capacity of its polysaccharides were investigated. The crude polysaccharides were extracted using the ultrasound-assisted water extraction method, precipitated by alcohol, and purified using the trichloroacetic acid method. Subsequently, the scavenging rates of polysaccharides on hydroxyl, DPPH, and ABTS free radicals, were determined both prior to and following purification to evaluate their antioxidant activity. Extraction technology was optimized to improve polysaccharide yield, and the optimal parameters were as follows: particle size 100 mesh, material–liquid ratio 1:84 (g/mL), ultrasonic time 30 min, and extraction for 95 min at 80 °C. The maximized extraction rate of crude polysaccharides was 37.78 ± 0.15%. The obtained crude polysaccharides were purified with different concentrations of trichloroacetic acid, and the purification effect was evaluated according to protein removal rate and polysaccharide retention rate, which could reach 62.61 ± 1.82% and 96.10 ± 1.60%, respectively. Infrared spectrum analysis suggested that Rhodymenia intricata polysaccharide might be α-pyranose. The Congo red test illustrated that the polysaccharide contained a triple helix structure. In the antioxidant activity assessment, the scavenging rates of polysaccharide prior to purification for RIP-1 (10 mg/mL) for hydroxyl, DPPH, and ABTS free radicals were observed to achieve maximum values of 94.71 ± 0.13%, 42.80 ± 7.12%, and 76.30 ± 5.20%, respectively. In contrast, the scavenging rates of polysaccharide following purification for RIP-2 (10 mg/mL) for the same free radicals reached maximum values of 94.10 ± 0.27%, 32.37 ± 0.78%, and 98.30 ± 0.34%, respectively. Notably, these scavenging rates exhibited a dose-dependent relationship. These results demonstrated the potential of the extraction method for polysaccharides from Rhodymenia intricata, and for adding value to the by-product for its potential application as an antioxidant in food and pharmaceutical products. [ABSTRACT FROM AUTHOR]