Red Algae Research Articles

Growth Performance of Kappaphycus alvarezii and Kappaphycus striatus cultivated in Ekas Bay, East Lombok Regency, West Nusa Tenggara Province

alvarezii is a superior product of Indonesian fisheries, producing carrageenan which is used as a food, cosmetic, and medicinal ingredient. K. striatus is a carrageenan-producing red alga that began to be cultivated in the Ekas waters of East Lombok in 2023. K. striatus is more resistant to epiphytes and sudden climate change. The purpose of this study was to analyze the growth of Kappaphycus alvarezii and Kappaphycus striatus. The research was conducted in Ekas Bay, Jerowaru District, East Lombok Regency. The research was conducted from November 8, 2023, to January 8, 2024. This research used an experimental method with T-test analysis. Treatments in this research are the cultivation of K. alvarezii and K. striatus. Cultivation was carried out at Ekas Bay. Analysis of seaweed carrageenan was carried out in the Laboratory of Fish Production and Reproduction, Aquaculture Study Program, Faculty of Agriculture, Mataram University. The result of this research is K. striatus has a higher absolute weight of 154 g compared to K. alvarezii seaweed which is 72 g. The specific growth rate K. striatus higher at 2,98 % / day compared to K. alvarezii is 1, 98 % / day. The yield of carrageenan of K. alvarezii is 1,95% and K. striatus 0,88%. Antioxidant of K. alvarezii is 5,46 % and K. striatus is 7,42%. Chlorophyll K. alvarezii is 5,77 mg/l and K. striatus is 3,51 mg/l. The conclusion of this study is the growth of K. striatus is faster than K. alvarezii.

Stress responses in an Arctic microalga (Pelagophyceae) following sudden salinity change revealed by gene expression analysis

Marine microbes that have for eons been adapted to stable salinity regimes are confronted with sudden decreases in salinity in the Arctic Ocean. The episodic freshening is increasing due to climate change with melting multi-year sea-ice and glaciers, greater inflows from rivers, and increased precipitation. To investigate algal responses to lowered salinity, we analyzed the responses and acclimatation over 24 h in a non-model Arctic marine alga (pelagophyte CCMP2097) following transfer to realistic lower salinities. Using RNA-seq transcriptomics, here we show rapid differentially expressed genes related to stress oxidative responses, proteins involved in the photosystem and circadian clock, and those affecting lipids and inorganic ions. After 24 h the pelagophyte adjusted to the lower salinity seen in the overexpression of genes associated with freezing resistance, cold adaptation, and salt tolerance. Overall, a suite of ancient widespread pathways is recruited enabling the species to adjust to the stress of rapid salinity change.

Do red tide events promote an increase in zooplankton biodiversity?

Red tides occurring off the southern coast of Korea impact the marine ecosystem and aquaculture industries. Zooplankton are crucial in the food web, connecting primary producers to higher predators and interact diversely with red tide organisms. This study explores dynamics of the zooplankton community over seven years including three red tide and four non-red tide years in Tongyeong using metabarcoding. In non-red tide years, zooplankton diversity showed typical seasonal patterns, increasing from June to early October. However, during red tide years, diversity remained high, with a shift in species composition-decreased Copepoda and increased Branchiopoda, Echinodermata, Malacostraca, and Annelida. Diversity indices were significantly higher in red tide years across all periods except for the richness in “after” that showed an insignificant higher value. The differences in zooplankton assemblages across periods were influenced by surface temperatures and the density of the red tide-causing alga Margalefidinium polykrikoides. Eight species emerged as indicator species and showed direct correlations with M. polykrikoides and among them, seven species were indicator species for red tide occurrence years. The ecological characteristics of M. polykrikoides blooms and their recurrent occurrences over several decades suggest that zooplankton may adapt to the toxins and use these blooms as spawning cues. Overall, this study provides comprehensive understanding on changes in zooplankton communities during red tide events, offering novel insights into their ecology.

Characterization and phylogenetic analysis of the complete mitochondrial genome of the red alga, Gracilaria eucheumatoides Harvey 1860 (Gracilariales: Gracilariaceae) from Vietnam

The marine red alga, Gracilaria eucheumatoides, is economically significant for its agar production and pharmacologically active compounds. This study reveals its complete mitochondrial genome (mitogenome), sequenced using Illumina’s next-generation technology. The mitogenome is a 25,909 bp circular molecule with a G + C content of 27.21%, comprising 24 protein-coding genes, two ribosomal RNA genes, 24 transfer RNA genes, and one open reading frame (ORF) with an unidentified function. Both gene structure and composition are highly conserved within Gracilaria. The phylogenetic analyses fully support a close relationship of G. eucheumatoides with other Gracilaria species, as well as its sister relationship with G. urvillei. This mitogenome sequencing effort of G. eucheumatoides provides crucial data for future phylogenetic research on marine red algae.

Antimicrobial and Cytotoxic Effect of Bornetella Nitida Green Algae Isolate on MCF-7 Breast Cancer.

Marine algae are increasingly becoming a potential resource for new drugs. In recent decades, including Bornetella nitida (B. nitida). Meanwhile, antimicrobial and anticancer agents are the first line of choice for developing alternative compounds, considering the annually increasing resistant events. Therefore, this study aimed to examine the antimicrobial and cytotoxic potential of B. nitida isolate compounds. The B. nitida resulted in 2 compounds, sitosterol 3β tetracosanoate and (E)-17-(8-ethyl-4,5,9-trimethyldec-6-en-2-yl)-13-methyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ol. Both compounds were tested to have antibacterial effects against Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Methicillin-resistant Staphylococcus Aureus (MRSA). Proliferation assay was conducted using the PrestoBlue™ Cell Viability Reagent, which was also used to measure the IC50 against MCF-7 breast cancer cells. The results showed that (E)-17-(8-ethyl-4,5,9-trimethyldec-6-en-2-yl)-13-methyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ol had antimicrobial activity against Staphylococcus aureus and IC50 value of 142.18 µg/mL against MCF-7 cells, while sitosterol 3β tetracosanoate does not have any antimicrobial activity and IC50 value of 681.65 µg/mL. Moreover, the mechanism prediction using docking with caspase-3 receptor to induce apoptosis was also evaluated. Based on the results, (E)-17-(8-ethyl-4,5,9-trimethyldec-6-en-2-yl)-13-methyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-ol of B. nitida has great potential as an antimicrobial and anticancer agent.

An unusual biofacies in a rocky shoreline succession of Vancouver Island, British Columbia, Canada: First record of Late Cretaceous coralline algae from the northeast Pacific region

Three common morphotypes of Sporolithon sp., as well as the peyssonneliacean red algae Polystrata, have been identified from Cretaceous clastic strata of Departure Bay, Vancouver Island, British Columbia. While coralline algae are known from the Cretaceous of Japan, they have not been recognized previously from the Cretaceous of the Pacific coast of North America. Mollusks associated with the coralline algae indicate an age of late early to early middle Campanian, corresponding to the time of maximum paleotemperature as represented in strata of the Nanaimo Group. The coralline algae are found in conglomerate and sandstone representing a basal transgressive facies of the Upper Cretaceous Nanaimo Group succession, resting unconformably on pillow basalts of the Upper Triassic Karmutsen Formation. This rocky shoreline facies is unusual in exhibiting extensive coralline algae packstone deposits. Paleodictyon is also found with the coralline algae, the first shallow-marine example of this trace fossil from the Cretaceous of the northeast Pacific region.

Red algae

Borg introduces the red algae - the largest living group of seaweeds.

Dietary regulation of gut bacteria in the Pacific oyster Magallana gigas and Mediterranean mussel Mytilus galloprovincialis

Feed composition affects the gut bacterial community in aquatic species, but little is known about how diet type impacts gut microbiota in molluscan bivalves. This study investigates the impact of feed composition on the gut bacterial community in two commercially important bivalves: Pacific oyster Magallana gigas and Mediterranean mussel Mytilus galloprovincialis. Oysters and mussels were fed with two types of marine algae, live Isochrysis galbana (microalgae) and the dried seaweed powder Ulva sp. (macroalgae) under a laboratory condition for two months. The V1–V2 region of the 16S rDNA was sequenced through an Illumina MiSeq platform to compare the gut bacterial community of oysters and mussels at the start and the end of the feeding trial. Feed composition directly impacted both alpha and beta diversities of gut microbiota, but the degree of the impact differed between bivalve species. The difference in the gut bacterial assemblages of oysters and mussels in the pre- and post-feeding trials indicated that the diet type and host species shape the composition of gut bacteria. Spirochaeta was absent in mussel guts during the pre- and post-feeding trials but was present in oysters, revealing host specificity in colonizing gut bacteria. The results suggest that the diet type and host species can significantly impact the gut bacterial community structure. This study confirms that diet can modulate gut microbial composition in marine filter-feeding organisms, but the extent of dietary modulation depends on feed type and host species.

Influence of a Mixture of Microbiology (Bacteria and Fungi) and Marine Alga Extracts on Some Growth Characteristics of Strawberry (cv. Roby Gem)

Influence of a Mixture of Microbiology (Bacteria and Fungi) and Marine Alga Extracts on Some Growth Characteristics of Strawberry (cv. Roby Gem)

Therapeutic Effect of Padina arborescens Extract on a Cell System Model for Parkinson's Disease.

Leucine-rich repeat kinase 2 (LRRK2) and α-synuclein are involved in the pathogenesis of Parkinson's disease. The activity of LRRK2 in microglial cells is associated with neuroinflammation, and LRRK2 inhibitors are crucial for alleviating this neuroinflammatory response. α-synuclein contributes to oxidative stress in the dopaminergic neuron and neuroinflammation through Toll-like receptors in microglia. In this study, we investigated the effect of the marine alga Padina arborescens on neuroinflammation by examining LRRK2 activation and the aggregation of α-synuclein. P. arborescens extract inhibits LRRK2 activity in vitro and decreases lipopolysaccharide (LPS)-induced LRRK2 upregulation in BV2, a mouse microglial cell line. Treatment with P. arborescens extract decreased tumor necrosis factor-α (TNF-α) gene expression by LPS through LRRK2 inhibition in BV2. It also attenuated TNF-α gene expression, inducible nitric oxide synthase, and the release of TNF-α and cellular nitric oxide in rat primary microglia. Furthermore, P. arborescens extract prevented rotenone (RTN)-induced oxidative stress in primary rat astrocytes and inhibited α-synuclein fibrilization in an in vitro assay using recombinant α-synuclein and in the differentiated human dopaminergic neuronal cell line SH-SY5Y (dSH). The extract increased lysosomal activity in dSH cells. In addition, P. arborescens extract slightly prolonged the lifespan of Caenorhabditis elegans, which was reduced by RTN treatment.

61 Effects of a calcareous marine algae on blood biochemistry during a heat wave in grain-fed steers

61 Effects of a calcareous marine algae on blood biochemistry during a heat wave in grain-fed steers

Preparation of Environmentally Friendly Bioplastics from Marine Red Algae, Salt Horned Seaweed, And Seaweed

Preparation of Environmentally Friendly Bioplastics from Marine Red Algae, Salt Horned Seaweed, And Seaweed

Nursery provision of red-algal habitats in temperate Algoa Bay, South Africa

This study examines the importance of both macroalgal heterogeneity and specific macroalgal species or morphotypes to nursery provision for juvenile sparids (Diplodus capensis and Sarpa salpa) in a shallow (< 2 m), sheltered rocky cove in warm-temperate Algoa Bay, South Africa. The rocky cove is comprised of a mosaic of two main benthic habitats; canopy-forming Plocamium corallorhiza beds on rocky outcrops and flat reef dominated by low growing red algae morphotypes. We assessed macroalgal communities and the trophic ecology (stomach contents and isotopes), abundance and size structure of D. capensis and S. salpa in the two different benthic habitats and the resources/food associated with the dominant macroalgae species/morphotypes. We found high densities of S. salpa and D. capensis, in both high profile reef (rocky outcrops) and low profile (flat) reef. Within this habitat mosaic resources (epiphytes and macroinvertebrates) were more abundant in the non-canopy forming low growing macroalgae (Laurencia spp. and coralline turf algae) and these algae were also assimilated in the diets of both sparids. The high abundance of both juvenile S. salpa and D. capensis in high profile and low profile reef, suggests that within this mosaic of habitats these species may be using canopy-forming algae in the high profile reef for shelter and non-canopy forming algae in both the high and low profile reef for food. This shows that macroalgal habitats comprising several morphotypes have the potential to support higher juvenile diversity and abundance through both food provision and shelter.

Efficient metal ions biosorption on red and green algae biomass: Isotherm, kinetic and thermodynamic study

Efficient metal ions biosorption on red and green algae biomass: Isotherm, kinetic and thermodynamic study

In situ structural determination of cyanobacterial phycobilisome–PSII supercomplex by STAgSPA strategy

Photosynthesis converting solar energy to chemical energy is one of the most important chemical reactions on earth. In cyanobacteria, light energy is captured by antenna system phycobilisomes (PBSs) and transferred to photosynthetic reaction centers of photosystem II (PSII) and photosystem I (PSI). While most of the protein complexes involved in photosynthesis have been characterized by in vitro structural analyses, how these protein complexes function together in vivo is not well understood. Here we implemented STAgSPA, an in situ structural analysis strategy, to solve the native structure of PBS–PSII supercomplex from the cyanobacteria Arthrospira sp. FACHB439 at resolution of ~3.5 Å. The structure reveals coupling details among adjacent PBSs and PSII dimers, and the collaborative energy transfer mechanism mediated by multiple super-PBS in cyanobacteria. Our results provide insights into the diversity of photosynthesis-related systems between prokaryotic cyanobacteria and eukaryotic red algae but are also a methodological demonstration for high-resolution structural analysis in cellular or tissue samples.

Commercially available carrageenans show broad variation in their structure, composition, and functionality

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.

Ecology of Intertidal Rocky Shores Related to Examples of Coastal Geology across Phanerozoic Time

The boundary between land and sea is among the most extensive and extreme ecological barriers on planet Earth. Intertidal organisms living at this junction are subject to potentially lethal conditions related to desiccation, temperature fluctuations, and wave shock. Although difficult to quantify at a global level, rocky coasts account for between a third and three-quarters of all shorelines today. Resistant to coastal erosion, rocky coasts also exhibit adaptations by marine invertebrates and marine algae within intertidal zones that are geographically widespread. Biotic composition is variable depending on the tidal range at any given place and on climatic differences between tropical and more temperate latitudes. Contemporary granite shores having low recession rates with well-established biotic zones are reviewed in three regions: Mount Desert Island in Maine, USA (44° N latitude), Mahé and Praslin islands in Seychelles (4°30′ S Latitude), and Lizard Island off the coast of Queensland, Australia (14°40′ S Latitude). The zonal composition and overall biotic diversity at these locations are compared, as well as the fossilization potential of key biota. Over the Phanerozoic time period during the last 538 million years, the ratio between land and ocean varied as a function of plate tectonics depending on the maximum dispersal or coalescence of continents and on relative changes in global sea level. Fossil biotas from a dozen paleoislands with dominant rocky shores that range from 485 million to 125,000 years in age are reviewed to show diversification through time, taking into account episodic mass extinctions. Relationships between storm tracks and volcanic eruptions that factor into physical disruptions are also considered as means of rapid burial and preservation. Themes related to rocky-shore ecology and paleoecology benefit from the cross-fertilization of ideas by marine biologists and marine paleontologists. It is hoped this review may attract a cohort of new students to these allied fields of study, especially in Asia, Africa, and South America.

Development of a two-stage SMB process based on two adsorbents with different hydrophobicities for continuous recovery of 3,6-anhydrogalactose from the acid hydrolysates of agarose in marine red algae

The notable medical efficacy of 3,6-anhydrogalactose (called “AHG” hereafter), the usefulness of galactose (called “GA” hereafter) as a biofuel source, and the need to utilize renewable resources have led to a significant increase in an interest in the economical productions of AHG and GA from agarose in marine red algae. One of the major challenges for realizing AHG and GA productions in this way has been to establish a highly efficient and reliable process for recoveries of both AHG and GA from the hydrolysates of agarose, which, however, has not been attempted so far. To address such issue, this study aimed to develop an optimal simulated-moving-bed (SMB) process for the continuous-mode and high-purity recoveries of AHG and GA from agarose hydrolysates. It was found first that a two-stage SMB structure based on using a less hydrophobic adsorbent in the 1st-stage SMB and a more hydrophobic adsorbent in the 2nd-stage SMB was most appropriate for the targeted SMB process. Under the environment of such selected SMB adsorbents, the intrinsic parameters of each component were determined, which were then applied to the optimization of the targeted SMB process. The simulations for such optimized process demonstrated that the front and rear of each solute wave were completely trapped within its corresponding zones in the optimized process, thereby enabling the SMB separation goal to be attained as designed. Finally, it was confirmed from the SMB experimental results that the optimized process allowed the continuous-mode recoveries of AHG and GA without loss, while maintaining 100% purities. Therefore, the developed SMB process in this study is expected to promote the economical productions of AHG and GA based on the utilization of agarose in marine red algae.

Abiotic triggers for maximising germling numbers in Asparagopsis taxiformis (Rhodophyta, Bonnemaisoniales) via tetrasporogenesis

AbstractThere is global interest in cultivating the red alga Asparagopsis taxiformis due to its efficacy as a potent anti-methanogenic feed supplement and as a biofilter for the bioremediation of nutrient-enriched waters. However, the development of A. taxiformis cultivation is currently hindered by a lack of information about the conditions required to maximise tetraspore release and thus secure a reliable source of germlings for out-planting. In this study, we examined the effects of temperature, irradiance, and standard nutrient supplementation (F/8, potassium iodide (KI) and arsenic trioxide (As2O3)) on the number of germlings produced per tetrasporophyte, using a strain of A. taxiformis widespread within the Great Barrier Reef, Australia. Temperature, irradiance and nutrient supplementation played a pivotal role in germling numbers, which was optimised at 22 °C under 7 µmol photons m−2 s−1 and with supplementation of F/8 nutrient media, arsenic trioxide (As2O3; 98 µg L−1) and potassium iodide (KI; 166 µg L−1). Once tetrasporophytes were removed from these inducing conditions, tetrasporogenesis ceased within 12 days. In a further five-week experiment investigating the effect of separate supplementation of As2O3 and KI, germling numbers were maximised under supplementation with either As2O3 or As2O3 + KI, with the relative growth rate of tetrasporophytes maximised under supplementation with F/8 + As2O3 + KI. Under optimum conditions, an average of 3,261 ± 826 (SD) germlings were produced per tetrasporophyte over a five-week period. Our results provide a strong starting point for developing hatchery protocols for generating a reliable supply of germlings for nursery cultivation in tropical settings.

Ultrasound Depolymerization and Characterization of Poly- and Oligosaccharides from the Red Alga Solieria chordalis (C. Agardh) J. Agardh 1842.

Red seaweed carrageenans are frequently used in industry for its texturizing properties and have demonstrated antiviral activities that can be used in human medicine. However, their high viscosity, high molecular weight, and low skin penetration limit their use. Low-weight carrageenans have a reduced viscosity and molecular weight, enhancing their biological properties. In this study, ι-carrageenan from Solieria chordalis, extracted using hot water and dialyzed, was depolymerized using hydrogen peroxide and ultrasound. Ultrasonic depolymerization yielded fractions of average molecular weight (50 kDa) that were rich in sulfate groups (16% and 33%) compared to those from the hydrogen peroxide treatment (7 kDa, 6% and 9%). The potential bioactivity of the polysaccharides and low-molecular-weight (LMW) fractions were assessed using WST-1 and LDH assays for human fibroblast viability, proliferation, and cytotoxicity. The depolymerized fractions did not affect cell proliferation and were not cytotoxic. This research highlights the diversity in the biochemical composition and lack of cytotoxicity of Solieria chordalis polysaccharides and LMW fractions produced by a green (ultrasound) depolymerization method.