Red Algae Research Articles

Enhancing strawberry quality and resistance to Botrytis cinerea using calcareous seaweed-derived Ca2+/carrageenan extracts

The dilute HCl pretreatment of the calcareous red alga, Liagora viscida, either at room temperature or 100 °C, produced Ca2+/carrageenan-containing extracts. Dipping strawberries in these extracts for 10 s demonstrated their ability to maintain various quality and nutritional traits during cold storage. The weight loss of the fruits after 7 days at 4 °C was reduced to 2.48–2.63 % in the treatments, compared to 3.26 % in the control. The treatments were effective in retaining the contents of vitamin C, titratable acidity, and phenolics, compared to marked reductions in the control. Additionally, the levels of anthocyanins, flavonoids, and the total antioxidant capacity were enhanced during cold storage. The treated fruits also showed higher chitinase activities, while the activities of cellulase, polygalacturonase, and pectin methylesterase (PME) showed remarkable reductions. The application of the extract derived at 100 °C reduced the decay caused by Botrytis cinerea decay to 34 % and 63.26 % after 3 and 4 days of infection, respectively, compared to 55.09–97 % in the untreated control. This reduction was concomitant with higher anthocyanins, flavonoids, and chitinase, and lower cellulase and PME in this treatment. The levels of malondialdehyde indicated less stressed fruits during both cold storage and fungal infection. Overall, the treatments promoted systemic resistance in the fruits, enhancing their ability to defend against pathogens. These results suggest the promising utilization of calcareous macroalgae as a sustainable biomass for developing a cost-effective and eco-friendly preservative to extend the shelf-life of strawberries during cold storage and enhance their resistance to pathogens.

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.

Altered excitation energy transfer between phycobilisome and photosystems in the absence of ApcG, a small linker peptide, in Synechocystis sp. PCC 6803, a cyanobacterium

Phycobilisome (PBS) is a large pigment-protein complex in cyanobacteria and red algae responsible for capturing sunlight and transferring its energy to photosystems (PS). Spectroscopic and structural properties of various PBSs have been widely studied, however, the nature of so-called complex-complex interactions between PBS and PSs remains much less explored. In this work, we have investigated the function of a newly identified PBS linker protein, ApcG, some domain of which, together with a loop region (PB-loop in ApcE), is possibly located near the PBS-PS interface. Using Synechocystis sp. PCC 6803, we generated an ApcG deletion mutant and probed its deletion effect on the energetic coupling between PBS and photosystems. Steady-state and time-resolved spectroscopic characterization of the purified ΔApcG-PBS demonstrated that ApcG removal weakly affects the photophysical properties of PBS for which the spectroscopic properties of terminal energy emitters are comparable to those of PBS from wild-type strain. However, analysis of fluorescence decay imaging datasets reveals that ApcG deletion induces disruptions within the allophycocyanin (APC) core, resulting in the emergence (splitting) of two spectrally diverse subgroups with some short-lived APC. Profound spectroscopic changes of the whole ΔApcG mutant cell, however, emerge during state transition, a dynamic process of light scheme adaptation. The mutant cells in State I show a substantial increase in PBS-related fluorescence. On the other hand, global analysis of time-resolved fluorescence demonstrates that in general ApcG deletion does not alter or inhibit state transitions interpreted in terms of the changes of the PSII and PSI fluorescence emission intensity. The results revealed yet–to–be discovered mechanism of ApcG-docking induced excitation energy transfer regulation within PBS or to Photosystems.

Utilizing marine algal metabolites to fight neurodegenerative diseases

Marine algae are thought to be a source of various metabolites that have a wide range of positive effects on human health. The pharmacological properties of algal metabolites, including their antioxidant, anti-inflammatory, cholesterol homeostasis, protein clearance, and anti-amyloidergic effects, lend credence to their protective efficacy against oxidative stress, neuroinflammation, mitochondrial dysfunction, and impaired proteostasis, all of which are involved in the pathophysiology of neurodegenerative disorders. There are currently no clinical trials on the effects of marine algae on neuroinflammation; however, considering the significant biological activities that have been established by in vitro and animal research, we expect that there will be clinical trials on this topic in the not-too-distant future. The most recent and important findings on the potentially neuroprotective effects of the anti-inflammatory properties of marine algae were chosen for this study. Next, we conducted a literature review on the neuroprotective potential of algal compounds, along with the underlying pharmacological mechanism, and finally, we evaluated recent advances in therapeutics.

Extraction methods of polysaccharides, peptides, pigments, polyphenols from red and brown algae and their use in the treatment of skin hyperpigmentation and wrinkling

The phenomenon of longevity and healthy aging as well as the factors that can slow down or even prevent the appearance of pathological conditions related to aging is a subject of interest in modern biology and medical research. In this context, a series of clinical and biochemical indicators are recorded and evaluated, as well as a wide variety of cellular aging biomarkers that include molecular signals and biomolecules at the proteomic, metabolomic, genomic and epigenetic level. The use of biomarkers to assess biological aging can help predict life expectancy and quality of life. The reliability of various biomarkers of aging should also be tested for validity against clinical markers of aging, such as frailty, loss of (physical) function, chronic diseases and disabilities.

Assessing the impact of sargassum algae biodiesel blends on energy conversion in a modified single-cylinder diesel engine with a silica-incorporated diamond-like coated piston

ABSTRACT As coal and oil reserves deplete, the world is shifting to alternative fuels and renewable energy. Researchers are exploring a cleaner alternative to fossil fuels for powering automobiles. In this investigation, biodiesel was synthesized from brown marine algae (Sargassum algae) using transesterification process. Silica-incorporated diamond-like coating (DLC) was done on the engine piston by using the chemical vapor deposition (CVD) process with flow rate of 7sccm of C2H2. Three different coating thicknesses, such as 50,100, and 150 µm, were employed on the CI engine piston. Mechanical properties such as hardness, wear, and microstructure analysis were investigated. Analysis of mechanical characteristics reveals that pistons with a 100 μm coating have enhanced characteristics compared to those with other pistons. Using a 100 μm silicon coated piston on a single-cylinder Kirloskar engine, four blends (B10, B20, B30, and B40) were compared to neat diesel. At maximum engine load conditions, the B40 blends produced 42 ppm of HC whereas neat diesel with 19 ppm which is 57% higher than diesel and CO emission concentration increased by 4.9% than diesel. Similarly, brake-specific fuel consumption was observed at maximum load conditions for diesel with 0.18 kg/kWh and 0.20 kg/kWh for B10D90 which is 9.54% higher than diesel. As a result, it is critical to recognize the importance of sargassum’s potential for producing sustainable energy toward green globalization.

Metabolomic Analysis and Antiviral Screening of a Marine Algae Library Yield Jobosic Acid (2,5-Dimethyltetradecanoic Acid) as a Selective Inhibitor of SARS-CoV-2.

Current small-molecule-based SARS-CoV-2 treatments have limited global accessibility and pose the risk of inducing viral resistance. Therefore, a marine algae and cyanobacteria extract library was screened for natural products that could inhibit two well-defined and validated COVID-19 drug targets, disruption of the spike protein/ACE-2 interaction and the main protease (Mpro) of SARS-CoV-2. Following initial screening of 86 extracts, we performed an untargeted metabolomic analysis of 16 cyanobacterial extracts. This approach led to the isolation of an unusual saturated fatty acid, jobosic acid (2,5-dimethyltetradecanoic acid, 1). We confirmed that 1 demonstrated selective inhibitory activity toward both viral targets while retaining some activity against the spike-RBD/ACE-2 interaction of the SARS-CoV-2 omicron variant. To initially explore its structure-activity relationship (SAR), the methyl and benzyl ester derivatives of 1 were semisynthetically accessed and demonstrated acute loss of bioactivity in both SARS-CoV-2 biochemical assays. Our efforts have provided copious amounts of a fatty acid natural product that warrants further investigation in terms of SAR, unambiguous determination of its absolute configuration, and understanding of its specific mechanisms of action and binding site toward new therapeutic avenues for SARS-CoV-2 drug development.

Phyto-chemical Profiling, Antimicrobial and Antioxidant Activity of Marine Brown Algae, Sargassum polycystum

Marine algae contain diverse bioactive compounds with pharmaceutical and nutraceutical importance. The present study was aimed at exploring one such alga, Sargassum polycystum, belonging to the phaeophyceae family. The seaweed was extracted with two different solvent systems and subjected to phytochemical analysis, antimicrobial and antioxidant studies. The extract showed wide variety of phytocomposition and was found to possess significant antimicrobial activity against bacterial and fungal pathogens. For antioxidant activities, DPPH assay, Hydroxyl radical scavenging assays, Phosphomolybdenum reduction and Fe3+ reducing power assays were carried out. The extract exhibited remarkable antioxidant activity in all the assays, especially in Fe3+ reducing power assay and hydroxyl radical scavenging, a maximum inhibition of 96.27 and 84.14% was observed, respectively. Also, the GC-MS analysis further confirmed the presence of isoflavone, a phenolic compound that signifies the role in antioxidant activity.

Super-slippery silicone-based gel coating with a regenerative oil layer for long-term prevention of surface contamination

Polymer-based gel-type coatings, in which oil molecules are absorbed within polymer networks, have drawn attention as functional coatings to address fouling problems. However, surface drought caused by lubricant depletion limits the longevity of conventional gel-type coatings. In this study, a super-slippery long-chain entangled polydimethylsiloxane (LEP) gel that can self-regenerate a low-viscosity oil layer is proposed to enhance its long-term anti-fouling performance in both indoor and marine habitats. The proposed LEP gel coating can effectively prevent contamination from numerous liquids and protect aluminum surfaces from corrosion in seawater. Even when it was incubated with Porphyridium purpureum, marine red algae that readily stick to the surface, no biofilm was formed on the coated samples for 37 weeks. In field tests, no biological adhesion was observed on the coating surface which was applied to port structures and left for two summer months. This enhanced anti-contamination performance is mainly attributed to the dual protective barrier comprising the underlying polymer layer and regenerative oil layer. Due to special property of continuous self-regeneration of oil layer, the proposed LEP gel surface demonstrates much enhanced sustainability, compared to conventional gel-type coatings. Consequently, the long-term anti-contamination performance of the super-slippery LEP gel coating would pave the way for novel approach to its practical applications.

A proposal for new genotoxic and cytotoxic endpoints to assess chemical effects on the red algae Ceramium tenuicorne.

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 10µm), 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, 1200mmol/L solution for 1min). 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 × 10-5M of CdCl2 and 5 × 10-5M of maleic hydrazide.

The Free-Running Circasemilunar Period Is Determined by Counting Circadian Clock Cycles in the Marine Midge Clunio Marinus.

Semilunar rhythms are found in numerous marine organisms, but the molecular mechanism and functional principles of endogenous circasemilunar clocks remain elusive. Here, we explore the connection between the free-running circasemilunar clock and the circadian clock in the marine midge Clunio marinus with three different chronobiological assays. First, we found that the free-running circasemilunar period of the adult emergence rhythm in C. marinus changes linearly with diel T-cycle length, supporting a day-counting mechanism. Second, under LD 6:6, periods of circasemilunar and circadian emergence were comparable to those under LD 12:12, indicating that the circasemilunar counter in C. marinus relies on endogenous circadian oscillations rather than external T-cycles. Finally, when desynchronizing the circadian clock with constant light, the free-running circasemilunar emergence rhythm disappeared as well, suggesting that it requires a synchronized circadian clock. These results oppose the long-held view that C. marinus' free-running circasemilunar clock operates independently of the circadian clock. In a broader evolutionary context, our results strengthen the idea that the circasemilunar clocks of dipterous insects are based on different functional principles compared to the circasemilunar or circalunar clocks of marine annelids and algae. These divergent clock principles may indicate multiple evolutionary origins of circasemilunar and circalunar clocks.

Edible-algae base composite film containing gelatin for food packaging from macroalgae, Gracilaroid (Gracilaria fisheri).

Conventional petroleum-based packaging films cause severe environmental problems. In the present study, bio-edible film was introduced as being safe to replace petroleum-based polymers. A food application for edible sachets and a composite edible film (EF) from marine algae, Gracilaria fisheri (GF) extract, were proposed. Carbohydrates were the most prevalent component in fresh GF fronds. Under neutral conditions comprising 90 °C for 40 min, the structure of the extract was determined by Fourier transform infrared to be a carrageenan-like polysaccharide. Glycerol was the best plasticizer for EF formation because it had the highest tensile strength (TS). The integration of gelatin into the algal composite film with gelatin (CFG) was validated to be significant. The best casting temperatures for 2 h were 70 and 100 °C among the four tested temperatures (25, 60, 70 and 100 °C). Temperatures did not result in any significant (P ≤ 0.05) differences in any character (color values, TS, water vapor permeability, oxygen transmission, thickness and water activity), except elongation at break. Visually, the CFG had a slightly yellow appearance. The best-to-worst order of film stability in the three tested solvents was oil, distilled water (DW) and ethanol. Its stability in ethanol (0-100%), temperature of DW (30-100 °C) and pH (3-7 in DW) demonstrated inverse relationships with the concentration or different conditions, except for pH 8-10 in DW. All treatments were significantly (P ≤ 0.05) different. The novel material made from polysaccharides from algae, G. fisheri, was used to improve EF. The edible sachet application is plausible from the EF. © 2024 Society of Chemical Industry.

Enhancing marine algae composites with cellulose nanofibrils for sustainable nutrient management

Enhancing marine algae composites with cellulose nanofibrils for sustainable nutrient management

Report on <i>Phaeophila dendroides</i> (Crouan) Batters Endophytic in <i>Rosenvingea intricata</i> (J. Ag.) Boergs.

Phaeophila dendroides (Crouan) Batters is reported here for the first time from North India from Chilka Lake. While the species is known as an endophyte in several marine algae belonging to Chlorophyta and Rhodophyta and a few marine Spermatophyta, it is reported here for the first time in a Phaeophyta in Roservingea intricata (J. Ag.) Boergs. The endophyte from Chilka Lake is described in some detail.

Extraction, Purification, Structural Characteristics, and Biological Activities of Seaweed Polysaccharides: A Review

AbstractThis paper presents a thorough review of the extraction, purification, structural characterization, and biological activities of polysaccharides obtained from seaweed. The focus is on the polysaccharide compositions of green algae, brown algae, and red algae, which are systematically compared and analyzed. It has been discovered that while there are similarities in the extraction and purification processes of seaweed polysaccharides, there are also significant differences and unique features in their structural characteristics and biological activities. These differences are not only reflected in the chemical composition of the polysaccharides but are also closely related to their sources and extraction methods. The relationship between the structure and activity of seaweed polysaccharides will aid in comprehending the biological activity mechanism of marine organisms. This review provides a theoretical basis and practical guidance for the development of new types of marine drugs or functional foods.

Antifungal Activities of Biogenic Silver Nanoparticles Mediated by Marine Algae: In Vitro and In Vivo Insights of Coating Tomato Fruit to Protect against Penicillium italicum Blue Mold.

In an attempt to reduce such decay induced by pathogenic causes, several studies investigated the effectiveness of nanoparticles (NPs) that play a vital role in saving food products, especially fruits. Current research delves into biogenic silver nanoparticles (using marine alga Turbinaria turbinata (Tt/Ag-NPs) and their characterization using FT-IR, TEM, EDS, and zeta potential. Some pathogenic fungi, which cause fruit spoilage, were isolated. We studied the impact of using Tt/Ag-NPs to protect against isolated fungi in vitro, and the influence of Tt/Ag-NPs as a coating of tomato fruit to protect against blue mold caused by Penicillium italicum (OR770486) over 17 days of storage time. Five treatments were examined: T1, healthy fruits were used as the positive control; T2, healthy fruits sprayed with Tt/Ag-NPs; T3, fruits infected with P. italicum followed by coating with Tt/Ag-NPs (pre-coating); T4, fruits coated with Tt/Ag-NPs followed by infection by P. italicum (post-coating); and T5, the negative control, fruits infected by P. italicum. The results displayed that Tt/Ag-NPs are crystalline, spherical in shape, with size ranges between 14.5 and 39.85 nm, and negative charges. Different concentrations of Tt/Ag-NPs possessed antifungal activities against Botrytis cinerea, Rhodotorula mucilaginosa, Penicillium expansum, Alternaria alternate, and Stemphylium vesicarium. After two days of tomatoes being infected with P. italicum, 55% of the fruits were spoilage. The tomato fruit coated with Tt/Ag-NPs delayed weight loss, increased titratable acidity (TA%), antioxidant%, and polyphenol contents, and decreased pH and total soluble solids (TSSs). There were no significant results between pre-coating and post-coating except in phenol contents increased in pre-coating. A particular focus is placed on the novel and promising approach of utilizing nanoparticles to combat foodborne pathogens and preserve commodities, with a spotlight on the application of nanoparticles in safeguarding tomatoes from decay.

Metabolic changes of the red marine alga Gracilariopsis tenuifrons elicited by high PAR in laboratory

Metabolic changes of the red marine alga Gracilariopsis tenuifrons elicited by high PAR in laboratory

Recent advances in in vitro and in vivo studies on Kappaphycus alvarezii and its derivatives.

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.

Accumulation and Quantitative Assessment of Terrigenous Organic Matter in Upper Oligocene to Lower Miocene Marine Source Rocks of the Qiongdongnan Basin.

The intense collision between marine and terrestrial agents results in the dual-source (marine and terrigenous) characteristics of marine source rocks. Our research quantitatively assessed terrestrial organic matter and revealed the crucial role of terrestrial organic materials in the organic matter enrichment of lower Miocene to upper Oligocene marine source rocks in the Qiongdognnan Basin. The quantitative assessment was achieved using partial least-squares analysis with eight biomarker parameters associated with n-alkanes, isoprenoids, bicadinanes, taraxerane, tricyclic terpanes, and gammacerane. Differential unloading of terrestrial organic materials based on sedimentary facies of the delta-marginal sea system were observed through oleanane and bicadinane contents. It should be noted that the diagnostic ratio of oleanane was excluded from the quantitative analysis due to the dual influence from differential unloading and contact with seawater of the terrestrial organic materials. Calculation results show that the terrestrial organic matter was highest in the delta front at 70%, followed by prodelta at 59% and inner shallow marine at 57%. From the late Oligocene to the early Miocene, the proportion of terrestrial organic matter in marine source rocks continuously increased, with the highest average value observed in the second member of the Sanya Formation at 69% and the lowest occurring in the third member of the Lingshui Formation at 46%. Increasing terrestrial organic material inputs and preservation driven by the East Asian summer monsoon provided first-order control of the accumulation of organic carbon in the Qiongdongnan Basin during late Oligocene to early Miocene, rather than the bioproductivity of marine algae. The redox conditions of the water column determine the enrichment extent of organic matter.

Antioxidant potential of three different Sea weeds from Visakhapatnam Coast, India

In the present study the antioxidant potential of three seaweeds Gracileria corticata (red algae), Ulva lactuca (green algae) and Sargassum ilicifolum (brown algae) were reported. SDS-PAGE analysis reveals that total of 23 different protein bands were observed of this 16, 14 and 17 bands in U. lactuca, S. ilicifolium and G. Corticata respectively. The chloroform, acetone and methanolic extracts of three algae showed the concentration dependent DPPH, FRAP, reducing power, H2O2 radical scavenging and metal chelating activities. The methanolic extracts of G. corticata have high levels of antioxidants with high DPPH, FRAP, reducing power activities and S. ilicifolum have high H2O2 radical scavenging, and metal chelating activities.G. corticata showed IC50 value for 902.09µg/ml for DPPH activity, 2274µg/ml for FRAP activity, 1082.11µg/ml for H2O2 radical scavenging. Among the three solvents tested, Methanol was found to be the most suitable solvent for the extraction of compounds.