Brown Alga Sargassum Polycystum Research Articles

Inductive role of the brown alga Sargassum polycystum on growth and biosynthesis of imperative metabolites and antioxidants of two crop plants.

The potential of macroalgae as biostimulants in agriculture was proved worthy. Vicia faba and Helianthus annuus are socioeconomic crops owing to their increasing demand worldwide. In this work, we investigated the energetic role of seed presoaking and irrigation by the brown seaweed, Sargassum polycystum aqueous extract (SAE) on certain germination and growth traits, photosynthetic pigments, carbohydrates, phenolics, flavonoids, and the total antioxidant activity. Compared to the control plants, our consequences revealed that seeds that received the SAE improved all the germination and growth criteria for both crop plants. Furthermore, the SAE significantly increased the carotenoids, total photosynthetic pigments, and total carbohydrates by (14%, 7%, and 41%) for V. faba and (17%, 17%, and 38%) for H. annuus, respectively. Phenolics and flavonoids were significantly induced in Vicia but slightly promoted in Helianthu plants, whereas the total antioxidant activity in both crops non significantly elevated. Even though The NPK contents were significantly stimulated by the SAE in Vicia plants, the effect was different in Helianthus, where only nitrogen content was significantly enhanced, whereas phosphorus and potassium showed little enhancement. Thus, the SAE treatment is one of the superlative sustainable strategies for food, feed, and as excellent plant conditioner.

Antiparasitic Potential of Methanol Extract of Brown Alga Sargassum polycystum (Phaeophyceae) and Its LC-MS/MS Metabolite Profiling

In Southeast Asian nations, cultured hybrid groupers are facing serious infestation by the marine parasitic leech Zeylanicobdella arugamensis (Annelida, Hirudinea). They attach to the hybrid groupers by sucking and biting on the surface of the skin, paving the way for secondary infection upon the fish. The objective of the study is to utilize the locally available seaweed to control the infestation of parasitic leeches. The methanol extracts of the brown alga Sargassum polycystum C. Agardh, 1824 (Phaeophyceae) from Sabah were prepared and investigated for antiparasitic efficacy against Z. arugamensis through in vitro bioassay. A total of 126 adult leeches from the host hybrid groupers were obtained from the fish hatchery. The parasitic leeches were treated with the methanol extracts of S. polycystum for 180 min by preparing five different dosages at concentrations of 100, 50, 25, 12.5, and 6.25 mg/mL. The brown alga was found to have high antiparasitic efficacy, resulting in 100% leech mortality over a short period of time. It showed the highest antiparasitic efficacy (total mortality of leeches) in a short time limit of 0.96 ± 0.44 min, for 100 mg/mL of the extract. Observations on leech behavior in the positive control and the seaweed extract treatments showed vigorous swimming before mortality. LC-MS/MS analysis was used to reveal the phytochemical composition of the extract to understand the nature of the main components responsible for its antiparasitic activities. A total of 29 metabolites were identified via Q Exactive HF Orbitrap mass spectrometry, including two flavonoids (ephedrannin A and hinokiflavone), two organoarsenics (1-dimethylarsinoyl-heptadecane and cacodylic acid), four heterocyclic compounds, and two chlorophyll breakdown products. The presence of bioactive compounds could increase the mortality rate of parasitic leeches. Thus, this study concludes that the brown alga showed high efficacy in its antiparasitic activities and can be effectively applied for treatment in grouper aquaculture farms for sustainable aquaculture.

Antioxidant activities of acetone extract of Sargassum polycystum from different parts of Thallus

Brown alga Sargassum polycystum in Indonesian waters is relatively abundant, and several studies show that brown alga has more antioxidant activity than red and green algae. Analysis of active compounds in the alga is generally carried out as a whole of macroalga thallus. This research was carried out to study the effect of thallus parts, namely basal, middle, and apical, on the antioxidant activity and fucoxanthin content in acetone extract of S. polycystum. The results determined the best part of the thallus as a producer of antioxidant compounds. The extraction was performed by an ultrasonic-assisted method using 90% acetone. The basal part contained the highest fucoxanthin of 1.00±0.025 mg/kg, while the most increased antioxidant activity was in the apical part of 65.78±5.31 μg/mL for the antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, 383.19±8.81 μmol ascorbic acid/g for the antioxidant activity of the cupric reducing antioxidant capacity (CUPRAC) method, and 964.75±3.91 μmol Fe2+/g for the antioxidant activity of the ferric reducing antioxidant power (FRAP) method. This study shows antioxidant activity had a negative correlation with the fucoxanthin content. It is concluded that fucoxanthin was not the major contributor to an antioxidant activity acetone extract of S. polycystum thallus.

Biofertilizing efficiency of Sargassum polycystum extract on growth and biochemical composition of Vigna radiata and Vigna mungo

Objective: To evaluate the effect of marine brown alga Sargassum polycystum extract on growth and biochemical parameters of Vigna radiata and Vigna mungo. Methods: Different concentrations of algal extracts (0.5%, 1.0%, 2.0%, 3.0%, 4.0%, and 5.0%) were prepared and applied to the crops at every 10-day intervals under natural conditions. After 30 d, the plants were harvested to evaluate the growth and biochemical parameters. Results: Seaweed liquid fertilizers treated seedlings showed maximum growth in 3.0% concentration when compared to the untreated seedlings. Similarly, biochemical parameters such as photosynthetic pigments, protein, reducing sugar, total sugar and amino acids exhibited increases in 3.0% concentration seaweed extract. Decreases in growth and biochemical parameters were noticed in concentrations higher than 3.0%. Conclusions: Presence of micronutrients and growth regulating substances in the liquid extract help healthier and faster productivity of the crop.

A late Pleistocene marine glacial refugium in the south‐west of Hainan Island, China: Phylogeographical insights from the brown alga Sargassum polycystum

AbstractAimHainan Island, southern China, is characterized by rich diversity and endemism of marine organisms, yet the underpinning mechanisms and processes contributing to speciation and diversification are poorly understood. Here, the brown alga Sargassum polycystum is used as a model to identify putative marine glacial refugia and explore biogeographical patterns driven by climate change in the late Pleistocene ice ages.LocationSouth‐East Asia.MethodsMitochondrial cox1 and cox3 and nuclear internal transcribed spacer‐2 (ITS2) were obtained from 310, 325 and 313 individuals of S. polycystum (23 localities), respectively. Phylogenetic trees (maximum likelihood and Bayesian inference) and haplotype/ribotype networks were constructed to elucidate phylogeographical patterns. Analysis of molecular variance (AMOVA), neutrality tests (Tajima's D and Fu & Li's D*), current (θπ) and historical (θw) genetic diversities and extended Bayesian skyline plots (EBSP) were used to estimate historical demography.ResultsThe populations from the south‐west of Hainan Island harboured much higher genetic diversity and unique endemism in comparison with other populations in the distribution range. Sargassum polycystum experienced relatively long‐term stable population size followed by a continued period of demographic expansion in the late Pleistocene.Main conclusionsOur phylogeographical evidence revealed the existence of a previously unidentified marine refugium specific to S. polycystum in the south‐west of Hainan Island, China (the Central Depression of the Yinggehai Basin), along with a possible secondary refugium around the Bali Island, Indonesia. These biogeographical findings provide important insights regarding speciation, adaptation and evolution of marine organisms in South‐East Asia and the conservation of unique biodiversity under climate change.

The enzymes of a marine bacterial isolate from the brown alga Sargassum polycystum agardh, 1821, that catalyzes the transformation of polyanionic oligo-and polysaccharides

A search for enzymes involved in the degradation of polyanionic polysaccharides (fucoidans and alginic acid) was conducted among bacterial epiphytes of the brown alga Sargassum polycystum that grows in the territorial waters of the Socialist Republic of Vietnam. Two resistant bacterial strains, F10 and F14, have been isolated from the algal microflora that degrade the thallus of the alga under laboratory conditions. These bacterial strains differed in the morphological, physiological, and biochemical characteristics and in the composition of enzymes. The strains were studied for the ability to synthesize intracellular oligo-and polysaccharide hydrolases and alginate lyases. The optimal conditions for the growth of bacterial strain F14 and the biosynthesis of fucoidanase and polymannuronate-specific alginate lyase were determined. The partially purified alginate lyase was stable at a temperature up to 40°C and had an optimal pH 6.0 and an optimal temperature 35°C.

Positive Feedbacks Enhance Macroalgal Resilience on Degraded Coral Reefs.

Many reefs have shifted from coral and fish dominated habitats to less productive macroalgal dominated habitats, and current research is investigating means of reversing this phase shift. In the tropical Pacific, overfished reefs with inadequate herbivory can become dominated by the brown alga Sargassum polycystum. This alga suppresses recruitment and survival of corals and fishes, thus limiting the potential for reef recovery. Here we investigate the mechanisms that reinforce S. polycystum dominance and show that in addition to negatively affecting other species, this species acts in a self-reinforcing manner, positively promoting survival and growth of conspecifics. We found that survival and growth of both recruit-sized and mature S. polycystum fronds were higher within Sargassum beds than outside the beds and these results were found in both protected and fished reefs. Much of this benefit resulted from reduced herbivory within the Sargassum beds, but adult fronds also grew ~50% more within the beds even when herbivory did not appear to be occurring, suggesting some physiological advantage despite the intraspecific crowding. Thus via positive feedbacks, S. polycystum enhances its own growth and resistance to herbivores, facilitating its dominance (perhaps also expansion) and thus its resilience on degraded reefs. This may be a key feedback mechanism suppressing the recovery of coral communities in reefs dominated by macroalgal beds.

Erratum to: The proliferating brown alga Sargassum polycystum in Tuvalu, South Pacific: assessment of the bloom and applications to local agriculture and sustainable energy

Since 2011, the small South Pacific atoll nation of Tuvalu has been affected by algal blooms, the most recent being a large growth of the brown alga Sargassum on the main atoll of Funafuti. The gravity of the situation led to an invitation to the authors from the Tuvalu Government to conduct an initial survey of the problem in November 2013. The bloom was seen to be localized on the lagoon side of the main populated island of Fongafale, distributed in a variably dense belt up to 100 m from the shoreline. A total of 19 species of macroalgae were found in the survey area, the dominant one being the phaeophyceaen alga, Sargassum polycystum C. Agardh, with individual plants reaching up to 2 m in length with a cover ranging between 16 and 23 % of the substratum. For seven transects laid from the southern tip of the island to the end of the populated area, wet biomass ranged between 0.45 and 3.56 kg m−2, with an average of 1.68 kg m−2. There was a correlation noticed between the density of human population on the shore and algal biomass, with the highest biomass figures opposite a school and a hotel. Water quality tests also showed nutrient levels almost twice as high in front of populated areas than in unpopulated areas of the island. The algal belt was seen to be concentrated in water less than 1 m deep, becoming sparser as depth increased. The high amount of Sargassum biomass available makes it a good candidate for use as a fertiliser additive for agricultural practices in Tuvalu. Benefits from seaweed-based fertilisers are numerous, and individual farmers have already reported success with the blooms species on the atoll. Additionally, the Sargassum biomass could be converted into biogas using the process of anaerobic digestion in simple household digesters, to meet the need for renewable energy in lighting and cooking.

The proliferating brown alga Sargassum polycystum in Tuvalu, South Pacific: assessment of the bloom and applications to local agriculture and sustainable energy

Since 2011, the small South Pacific atoll nation of Tuvalu has been affected by algal blooms, the most recent being a large growth of the brown alga Sargassum on the main atoll of Funafuti. The gravity of the situation led to an invitation to the authors from the Tuvalu Government to conduct an initial survey of the problem in November 2013. The bloom was seen to be localized on the lagoon side of the main populated island of Fongafale, distributed in a variably dense belt up to 100 m from the shoreline. A total of 19 species of macroalgae were found in the survey area, the dominant one being the phaeophyceaen alga, Sargassum polycystum C. Agardh, with individual plants reaching up to 2 m in length with a cover ranging between 16 and 23 % of the substratum. For seven transects laid from the southern tip of the island to the end of the populated area, wet biomass ranged between 0.45 and 3.56 kg m−2, with an average of 1.68 kg m−2. There was a correlation noticed between the density of human population on the shore and algal biomass, with the highest biomass figures opposite a school and a hotel. Water quality tests also showed nutrient levels almost twice as high in front of populated areas than in unpopulated areas of the island. The algal belt was seen to be concentrated in water less than 1 m deep, becoming sparser as depth increased. The high amount of Sargassum biomass available makes it a good candidate for use as a fertiliser additive for agricultural practices in Tuvalu. Benefits from seaweed-based fertilisers are numerous, and individual farmers have already reported success with the blooms species on the atoll. Additionally, the Sargassum biomass could be converted into biogas using the process of anaerobic digestion in simple household digesters, to meet the need for renewable energy in lighting and cooking.

Stereoselective synthesis of a sulfated tetrasaccharide corresponding to a rare sequence in the galactofucan isolated from Sargassum polycystum.

The first chemical synthesis of a highly sulfated tetrasaccharide 1, as the rare sequence in the galactofucan isolated from the brown alga Sargassum polycystum, was achieved in a convergent and stereoselective manner. The key features of the synthetic strategy include construction of multiple contiguous 1,2-cis glycosidic bonds and [2 + 2] assembly based on the rationally developed d-galactose building block 6. The synthesized oligosaccharides were fully characterized using a combination of coupled-HSQC and other 2D NMR techniques.

Homogeneous population of the brown alga Sargassum polycystum in Southeast Asia: possible role of recent expansion and asexual propagation.

Southeast Asia has been known as one of the biodiversity hotspots in the world. Repeated glacial cycles during Pleistocene were believed to cause isolation of marine taxa in refugia, resulting in diversification among lineages. Recently, ocean current was also found to be another factor affecting gene flow by restricting larval dispersal in animals. Macroalgae are unique in having mode of reproduction that differs from that of animals. Our study on the phylogeographical pattern of the brown macroalga Sargassum polycystum using nuclear Internal Transcribed Spacer 2 (ITS2), plastidal RuBisCO spacer (Rub spacer) and mitochondrial cytochrome oxidase subunit-III (Cox3) as molecular markers revealed genetic homogeneity across 27 sites in Southeast Asia and western Pacific, in sharp contrast to that revealed from most animal studies. Our data suggested that S. polycystum persisted in single refugium during Pleistocene in a panmixia pattern. Expansion occurred more recently after the Last Glacial Maximum and recolonization of the newly flooded Sunda Shelf could have involved asexual propagation of the species. High dispersal ability through floating fronds carrying developing germlings may also contribute to the low genetic diversity of the species.

Preliminary investigation of a highly sulfated galactofucan fraction isolated from the brown alga Sargassum polycystum

A fucoidan preparation was isolated from the brown alga Sargassum polycystum (Fucales, Sargassaceae). The preparation was fractionated by anion-exchange chromatography, and two highly sulfated fractions F3 and F4 were obtained. The fractions were quite similar in composition, but different in chemical structure. F4 was analyzed by chemical methods, including desulfation, methylation, Smith degradation, and partial acid hydrolysis with mass-spectrometric monitoring, as well as by NMR spectroscopy. Several 2D NMR procedures, including HMQC-TOCSY and HMQC-NOESY, were used to obtain reliable structural information from the complex spectra. Molecules of F4 were shown to contain a backbone built up mainly of 3-linked α-l-fucopyranose 4-sulfate residues, as in many other fucoidans, but rather short sequences of these residues are interspersed by single 2-linked α-d-galactopyranose residues also sulfated at position 4. This rather unusual structural feature should have a great influence on the conformation of the polymeric molecule and may be important for biological activity of the polysaccharide. Hence, F4 is an example of a new sulfated galactofucan isolated from the brown alga. According to the data obtained, the distribution of galactose residues along the polysaccharide backbone seems to be not strictly regular, but the definitive sequence of monomers in the polymeric molecules awaits additional investigation.

Detection of ionic liquid stable cellulase produced by the marine bacterium Pseudoalteromonas sp. isolated from brown alga Sargassum polycystum C. Agardh

An extracellular cellulase produced by marine bacterium Pseudoalteromonas sp. was studied for its activity and stability in six different ionic liquids (ILs) over a wide range of concentrations (1–20% v/v) and compared with aqueous medium as control. Enzyme showed its optimal activity at 45°C and at pH 5 in control. Although the activity varied with the type of IL and its concentration used, the activity measured at 5% (v/v) was maximum with [EMIM]Br followed by [EMIM]Ac, [BMIM]Cl, [C2MIM][CH3SO3], [BMIM][OTF] and [BMPL][OTF] with 115%, 104.7%, 102.2%, 98.33%, 93.84% and 92.67%, respectively, and >80% activity at 15% (v/v) in all ILs. The enzyme stability at 5% (v/v) IL concentration for 36h was superior to commercial cellulase. The cellulase activity enhanced by 1.35- to 1.72-fold over control when 5% (v/v) IL based reaction medium with algal biomass was used and thus showed potentials for saccharification of biomass in a single step process.