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Chemical analysis of the organic extract from intertidal brown seaweed Sargassum ilicifolium (family Sargassaceae) characterised an undescribed xenicane-type diterpenoid sargilicixenicane, elucidated as 3-(17-hydroxy-14-methylhept-13-en-10-yl)-6-methylhexahydro-1 H -cyclonona[c]furan-4,19-diyl diacetate (compound 1). The studied compound exhibited prospective free radical quenching potential (IC 50 1.2-1.4 mM) in comparison with commercial antioxidant ( α- tocopherol, IC 50 > 1.40 mM). Attenuation property of sargilicixenicane against pro-inflammatory enzyme, 5-lipoxygenase (IC 50 4.70 mM) was comparable with that displayed by the non-steroidal anti-inflammatory agent ibuprofen (IC 50 4.51 mM). Greater selectivity index displayed by the studied xenicane-type diterpenoid (1.42) than that exhibited by ibuprofen (0.44) recognised the selective attenuation potential of the former against the inducible cyclooxygenase-2 and 5-lipoxygenase enzymes. Higher electronic parameters (topological polar surface area, 82.06) and balanced hydrophobic-hydrophilic property (octanol-water partition coefficient 2.94) coupled with docking score (-11.17 kcal mol -1 ) and lower binding energy (-9.61 kcal mol -1 ) with the active site of 5-lipoxygenase supported the significant anti-inflammatory properties of the studied xenicane-type diterpenoid.

Four previously undescribed antioxidative O-heterocyclic analogues, characterized as 3″-isopropyl-3c-{3b-[(2-oxo-3,4-dihydro-2H-chromen-3-yl) methyl] butyl}-2″-butenyl-3'-hydroxy-2'-(2'b-methoxy-2'-oxoethyl)-3', 4'-dihydro-2H-pyran-4'-carboxylate (1), 2c-methylbutyl-6-[6c-(benzoyloxy)propyl]-6-methyl-tetrahydro-2H-pyran-2-carboxylate (2), 6-{6b-[3'-(5'a-methyl propyl)-3', 4'-dihydro-2H-pyran-6'-yl] ethyl}-tetrahydro-2H-pyran-2-one (3) and 7-(7c-methylpentyl)-hexahydro-2H-chromen-2-one (4) were isolated from the ethylacetate:methanol fraction of the brown seaweed Sargassum wightii. Nuclear magnetic resonance and mass spectroscopic experiments unambiguously attributed their structural identities. Antihypertensive activities of the studied compounds were determined in terms of their angiotensin converting enzyme (ACE) inhibitory potential. The 2H-pyranylcarboxylate derivative (1) displayed comparable activity (IC 50 0.08 mg/mL) with standard antihypertensive agent captopril (IC 50 0.07 mg/mL). The O-heterocyclic derivatives bearing 2H-pyran-4'-carboxylate (1) and 2H-pyran-2-carboxylate (2) frameworks showed significantly greater (p < 0.05) 1, 1-diphenyl-2-picryl-hydrazil radical quenching potential {IC 50 (1) 0.34 and IC 50 (2) 0.45 mg/mL} compared to the standard antioxidant α-tocopherol (IC 50 0.63 mg/mL). Structure-activity relationship analyses demonstrated that the electronic and lipophilic descriptors might significantly contribute towards the target bioactivities of 2H-pyranylcarboxylates (1 and 2). Molecular docking simulations were carried out for ACE inhibition, and the binding energy obtained for the compounds (~7.04-8.48 kcal/mol) demonstrated their potential enzyme-ligand interactions. The potential of hitherto undescribed O-heterocyclic derivatives as natural antioxidant and antihypertensive functional food supplements and their utilization as therapeutic leads in the antihypertensive management were described in the present study., (Copyright © 2018. Published by Elsevier Ltd.)

Previously undescribed fridooleanene triterpenoids 2α-hydroxy-(28,29)-frido-olean-12(13), 21(22)-dien-20-propyl-21-hex-4'(Z)-enoate, 2α-hydroxy-(28,29)-frido-olean-12(13), 21(22)-dien-20-prop-2(E)-en-21-butanoate and oxygenated labdane diterpenoids 2α-hydroxy-8(17), (12E), 14-labdatriene, 3β, 6β, 13α-tri hydroxy 8(17), 12E, 14-labdatriene were purified from the ethyl acetate-methanol and dichloromethane fractions of the air-dried thalli of Sargassum wightii (Sargassaceae), a brown seaweed collected from the Gulf-of-Mannar of Penninsular India. Inhibitory potential of Δ 12 oleanenes towards protein tyrosine phosphatase-1B, the critical regulator of insulin-receptor activity were found to be significantly greater (IC 50 0.1 × 10 -2 and 0.09 × 10 -2  mg/mL, respectively) than the standard sodium metavanadate (IC 50 0.31 × 10 -2  mg/mL). Fridooleanene triterpenoids displayed greater antioxidant activities (IC 50DPPH 0.16-0.18 mg/mL) than the commercially available antioxidants, butylated hydroxytoluene and α-tocopherol (IC 50DPPH 0.25 and 0.63 mg/mL, respectively). In general, the oxygenated labdane diterpenoids displayed significantly lesser antioxidant and tyrosine phosphatase-1B inhibitory properties than those exhibited by the fridooleanenes. Bioactivities of the titled compounds were primarily determined by the electronic and lipophilic parameters and not by the steric descriptors. Molecular docking simulations and kinetic studies were employed to describe the tyrosine phosphatase-1B inhibitory mechanism. The previously undescribed fridooleanene triterpenoids might be used as potential anti-hyperglycaemic pharmacophore leads to reduce the risk of elevated postprandial glucose levels., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Sargassum vachellianum C. Agardh is endemic to China. It inhabits in rocky intertidal zones and plays an important role in maintaining the structure and function of littoral ecosystems. In this study, we present the complete mitochondrial genome of S. vachellianum. The circular S. vachellianum mitogenome is 34,877 bp in size and contains the same set of 65 genes as the reported Sargassum mtDNAs. The overall AT content of the genome is 63.79%, and the inter-genic spacers constitute only 4.67%. The genome organization including the gene order, overlapping regions between genes, and the total length of inter-genic spacers is conserved among the known Sargassum mitogenomes. High divergence is in inter-genic spacer regions. Phylogenetic analyses indicated that S. vachellianum combined tightly with Sargassum species with strong support values (NJ/ML, 100%).

Sargassum hemiphyllum (Turner) C. Agardh is a common low intertidal brown alga in the northwestern Pacific, and two varieties (var. chinense and var. hemiphyllum) of this alga have been determined based on morphological and molecular data. In this study, we present the complete mitochondrial genome of S. hemiphyllum var. chinense. The circular-mapping S. hemiphyllum mitogenome of 34,686 bp has an overall A+T content of 63.43%, and contains 65 densely packed genes. The total intergenic spacer regions are 1597 bp, constituting 4.60% of the mitogenome. The gene content and genome organization of S. hemiphyllum are identical to that of other reported Sargassum species. The identity comparison of overall mitogenome sequences and phylogenomic analyses indicate that S. hemiphyllum has a closer evolutionary relationship with Sargassum muticum than other Sargassum species analyzed. The present mitogenomic data provide a powerful tool for definition of varieties and studies of population structure in S. hemiphyllum.

Sargassum muticum (Yendo) Fensholt is an invasive canopy-forming brown alga, expanding its presence from Northeast Asia to North America and Europe. The complete mitochondrial genome of S. muticum is characterized as a circular molecule of 34,720 bp. The overall AT content of S. muticum mitogenome is 63.41%. This mitogenome contains 65 genes typically found in brown algae, including 3 ribosomal RNA genes, 25 transfer RNA genes, 35 protein-coding genes, and 2 conserved open reading frames (ORFs). The gene order of mitogenome for S. muticum is identical to that for Sargassum horneri, Fucus vesiculosus and Desmarestia viridis. Phylogenetic analyses based on 35 protein-coding genes reveal that S. muticum has a close evolutionary relationship with S. horneri and a distant relationship with Dictyota dichotoma, supporting current taxonomic systems. The present investigation provides new molecular data for studies of S. muticum population diversity as well as comparative genomics in the Phaeophyceae.

Sargassum fusiforme (Harvey) Setchell (=Hizikia fusiformis (Harvey) Okamura) is one of the most important economic seaweeds for mariculture in China. In this study, we present the complete mitochondrial genome of S. fusiforme. The genome is 34,696 bp in length with circular organization, encoding the standard set of three ribosomal RNA genes (rRNA), 25 transfer RNA genes (tRNA), 35 protein-coding genes, and two conserved open reading frames (ORFs). Its total AT content is 62.47%, lower than other brown algae except Pylaiella littoralis. The mitogenome carries 1571 bp of intergenic region constituting 4.53% of the genome, and 13 pairs of overlapping genes with the overlap size from 1 to 90 bp. The phylogenetic analyses based on 35 protein-coding genes reveal that S. fusiforme has a closer evolutionary relationship with Sargassum muticum than Sargassum horneri, indicating Hizikia are not distinct evolutionary entity and should be reduced to synonymy with Sargassum.

Sargassum is one of the most important genera of the family Sargassaceae in brown algae and is used to produce carrageenan, mannitol, iodine, and other economic substances. Here, seven complete plastid genomes of Sargassum ilicifolium var. conduplicatum, S. graminifolium, S. phyllocystum, S. muticum, S. feldmannii, S. mcclurei , and S. henslowianum were assembled using next-generation sequencing. The sizes of the seven circular genomes ranged from 124,258 to 124,563 bp, with two inverted regions and the same set of plastid genes, including 139 protein-coding genes (PCGs), 28 transfer (t)RNAs, and 6 ribosomal (r)RNAs. Compared with the other five available plastid genomes of Fucales, 136 PCGs were conserved, with two common ones shared with Coccophora langsdorfii , and one with S. fusiforme and S. horneri. The co-linear analysis identified two inversions of trnC(gca) and trnN(gtt) in ten Sargassum species, against S. horneri and C. langsdorfii. The phylogenetic analysis based on the plastid genomes of 55 brown algae (Phaeophyceae) showed four clades, whose ancient ancestor lived around 201.42 million years ago (Mya), and the internal evolutionary branches in Fucales started to be formed 92.52 Mya, while Sargassum species were divided into two subclades 14.33 Mya. Our novel plastid genomes provided evidence for the speciation of brown algae and plastid genomic evolution events. [ABSTRACT FROM AUTHOR]

The brown alga, Sargassum natans, forms groups of pelagic thalli, and is also found in the macroalgae barrages that eventually occur in the Caribbean region. In this work, a new species for the phycological flora of Venezuela is reported, with contributions to the description of some vegetative structures of a population of S. natans found in the sector La Caracola of Moreno Beach, Margarita Island, during the month of April 2018. Three specimens were collected and preserved in 4% formaldehyde. The analysis of the vegetative structures by means of a stereoscopic microscope, revealed the presence of densely divided lateral branches with abundant pneumatophores that presented acicular appendages or a phyllodes-like projection, and the absence of lateral wings on their pedicels, the phylloids with toothed edges and few or no cryptostomes on the sheets, which allowed the identification of the specie as Sargassum natans (Linnaeus) Gaillon, belonging to the family Sargassaceae Kutzing. This species had not been recorded in the marinecoastal zone of Venezuela, so its distribution is expanded in the Caribbean Sea. [ABSTRACT FROM AUTHOR]

SUMMARY We investigated the monthly variations of estimated in‐situ uptake and growth‐related demand for phosphorus in Sargassum macrocarpum during a growth period from December 2017 to April 2018, a maturation period from May to August 2018, and the second‐growth period from September 2018 to January 2019. Phosphate uptake was relatively low during maturation and high during growth, and coincided with changes in external phosphate levels. The demand for phosphorus was at its highest in March 2018, which corresponded with the highest growth rate and tissue phosphorus levels. Thereafter, the demand was relatively constant between April 2018 and January 2019. Consequently, the uptake rate exceeded demand from December 2017 to February 2018 and December 2018 to January 2019, suggesting that phosphorus accumulated in tissues. Additionally, the uptake rates between March 2018 and November 2018 were 0.1–0.8 times lower than the demand, probably resulting in the effective use of stored phosphorus to sustain growth during this phosphate‐depleted period. The variations between estimated uptake and demands for P found in S. macrocarpum indicate that P dynamics vary with life stage and are implicitly linked to the season. [ABSTRACT FROM AUTHOR]

SUMMARY: The effects of irradiance, temperature, thermal‐ and chilling‐light sensitivities on the photosynthesis of a temperate alga, Sargassum macrocarpum (Fucales) were determined by a pulse amplitude modulation (PAM)‐chlorophyll fluorometer and dissolved oxygen sensors. Oxygenic photosynthesis–irradiance curves at 8, 20, and 28°C revealed that the maximum net photosynthetic rates (NPmax) and saturation irradiance were highest at 28°C, and lowest at 8°C. Gross photosynthesis and dark respiration determined over a range of temperatures (8–36°C) at 300 μmol photons m−2 s−1 revealed that the maximum gross photosynthetic rate (GPmax) occurred at 27.8°C, which is consistent with the highest seawater temperature in the southern distributional limit of this species in Japan. Additionally, the maximum quantum yields of photosystem II (Fv/Fm) during the 72‐h temperature exposures were stable at 8–28°C, but suddenly dropped to zero at higher temperatures, indicative of PSII deactivation. Continuous exposure (12 h) to irradiance of 200 (low) and 1000 (high) μmol photons m−2 s−1 at 8, 20, and 28°C revealed greater declines in their effective quantum yields (ΦPSII) under high irradiance. While ΦPSII under low irradiance were very similar with the initial Fv/Fm under 20 and 28°C, values rapidly decreased with exposure duration at 8°C. At this temperature, Fv/Fm did not recover to initial values even after 12 h of dark acclimation. Final Fv/Fm of alga at 28°C under high irradiance treatment also did not recover, suggesting its sensitivity to photoinhibition at both low and high temperatures. These photosynthetic characteristics reflect both the adaptation of the species to the general environmental conditions, and its ability to acclimate to seasonal changes in seawater temperature within their geographical range of distribution. [ABSTRACT FROM AUTHOR]

Sargassum in the Caribbean region has affected the livelihood of several coastal communities due to the influx of large quantities of the seaweed in recent times. This article seeks to explore how waste Sargassum natans can be utilized to produce sodium alginate. The novelty in this research lies in the optimization process, whereby multistage extraction and precipitation were investigated over commonly used single stage processing, in an effort to maximize both yield and purity. The results showed that a maximum yield of 19% was observed after 1 stage, while the purity was 74% after 4 stages. In addition, optimization of the multistage precipitation process using the Global Optimization Toolbox in MATLAB R2017b provided a novel model which indicated that a compromise between the maximum purity and yield can be obtained at 3 stages; 71–74% and 12–16% respectively. Furthermore, characterization was done using FTIR and NMR, with results comparable to a commercial sodium alginate brand, giving absorption bands at 1610 cm −1 and 1395 cm -1 and an M/G ratio of 0.51 respectively. [ABSTRACT FROM AUTHOR]

The presence ofd-aspartate (d-Asp), a biologically rare amino acid, was evaluated in 38 species of marine macroalgae (seaweeds). Despite the ubiquitous presence of freel-Asp, freed-Asp was detected in only 5 species belonging to the Sargassaceae family of class Phaeophyceae (brown algae) but not in any species of the phyla Chlorophyta (green algae) and Rhodophyta (red algae). All other members of Phaeophyceae, including 3 species classified into the sectionTeretiaof Sargassaceae did not containd-Asp. These results indicate that the presence of freed-Asp in marine macroalgae is restricted only to the Sargassaceae family, excluding the species in the sectionTeretia. Presence of d-Aspartate in macroalgae is restricted to the Sargassaceae family exceptTeretiasection [ABSTRACT FROM PUBLISHER]

To elucidate the evolution of mitochondrial genomic diversity between two Sargassum subgenera, Bactrophycus and Sargassum, we sequenced four Sargassum genomes in subgenus Sargassum, including Sargassum polycystum C. Agardh, S. spinuligerum Sonder, S. ilicifolium (Turner) C. Agardh, and S. aquifolium (Turner) C. Agardh. Mitogenome sizes of these four species ranging from 34,761 to 34,925 bp are longer than those in subgenus Bactrophycus (34,606 to 34,748 bp), and the content of non-coding regions (4.68-5.25%) is higher than that in Bactrophycus (4.29-4.65%) . The evolutionary traits of single mitochondrial genes show apparent inconsistency between the two Sargassum subgenera. Mitogenome sequence identities are from 92.4 to 99.1% in subgenus Sargassum and from 87.6 to 92.7% in subgenus Bactrophycus. Based on the whole mitogenome dataset, ten Sargassum species are clustered into two subclades representing two subgenera, Sargassum and Bactrophycus. Only four individual single-gene phylogenies ( cox2, nad6, rpl5, and rps3) show that the ten Sargassum species could be strongly clustered and divided into two subgenera with high values (ML/NJ/BI ≥70%). The study indicates that the two subgenera, Sargassum and Bactrophycus, are distinct evolutionary entities, and mitogenomic traits provide novel insights into Sargassum deep-level relationships. [ABSTRACT FROM AUTHOR]

A fucoidan preparation named FSA was isolated from the brown alga Sargassum aquifolium collected from the coastal waters of Vietnam. l -Fucose, d -galactose, d -mannose, d -glucuronic acid, d -xylose, and sulfate were found to be the main constituents of FSA. The preparation was fractionated by anion-exchange chromatography on DEAE-Sephacel eluted stepwise with 0.5, 1.0, 1.5, and 2.0 M NaCl to give four fractions differing in monosaccharide composition and degree of sulfation. Their NMR spectra were too complex to be completely interpreted. Fractions 1.0 M and 1.5 M were analyzed by methylation before and after desulfation. In addition, desulfated 1.0 M was fractionated by anion-exchange chromatography into six fractions according to the uronic acid content. They were characterized by methylation and NMR spectral data, and three structurally different polysaccharides were identified. One of them has a core of alternating 2-linked α- d -Man p and 4-linked β- d -Glc p A residues, about a half of the former bearing single α- l -Fuc p or β- d -Xyl p at position 3. The second polymer is a (1 → 3)-β- d -glucopyranuronan partially substituted with single β- d -Xyl p or single α- l -Fuc p at position 4. The third polysaccharide is a xylo(fuco)galactan having a linear core of alternating 4-linked α- d -Gal and 3-linked β- d -Gal residues. The latter bear single β- d -Xyl p or a short chain of 4-linked β- d -Xyl, 6-linked β- d -Gal, and variously linked α- l -Fuc. In FSA, these polysaccharides are sulfated at different positions and devoid of regularity. Fractions of FSA possess anticoagulant, cytotoxic, and antitumor activities, which increase with the degree of sulfation. The most sulfated fraction 2.0 M that contains mainly a sulfated fucogalactan, is about half as active as anticoagulant as the standard low-molecular mass heparin (enoxaparin). [ABSTRACT FROM AUTHOR]

Biosorption of Methyl Blue (MB), Fuchsin Acid (FA), Rhodamine B (RB), Methylene Blue (MEB), Bromocresol purple (BC) and Methyl Orange (MO) onto Sargassum ilicifolium was studied in a batch system. Effect of dye structure on biosorption by Sargassum ilicifolium was studied to define the correlation between chemical structure and biosorption capacity. Different dye groups such as triarylmethane (MB, FA and BC), monoazo (MO), thiazine (MEB) and xanthene (RB) were studied. At optimum experimental conditions for each dye, biosorption capacity was determined and compared. The results indicate that the chemical structure (triarylmethane, monoazo, thiazine, xanthene), number of sulfonic groups, basicity (element of chromophore group: S, N, O) and molecular weight of dye molecules influence their biosorption capacity. Experimental parameters such as biosorbent dose, pH, contact time, and initial dye concentration were optimized for each dye. The biosorption kinetic data were successfully described by the pseudo second-order model. The biosorption results were also analyzed by the Langmuir and Freundlich isotherms. Finally, biosorption capacities obtained using Sargassum ilicifolium were compared with the ones presented in the literature. [ABSTRACT FROM AUTHOR]

Introduction: This study focused on the discussion of effect of various extraction conditions for phlorotannin content and antioxidant activities extracted from brown algae Sargassum serratum. The algae was grown in the tropical coastal areas of Vietnam. Methods: The various extraction conditions include the following parameters: temperature (30-80°C), maceration time (1/2-2,5 hours; 8-48 hrs), the ratio of solvent to material (10:1-70:1 (v/w)), pH (2-8), various kind of solvents (ethanol, acetone, chloroform, ethyl acetate and n-hexan) and solvent concentrations. Phlorotannin content, antioxidant activities, and some phytochemical compositions of Sargassum serratum were evaluated. Results: The highest phlorotannin content and antioxidant activities was expressed when extracting in the following conditions: 100% ethanol solvent at 500C in 32 hours with the ratio of solvent to material of 40/1 (v/w), pH 7 and one-step extraction. The extract contained flavonoid, terpenoid, alkaloid, fatty and oil. DPPH free radical scavenging of the extract was 87.53%. Conclusion: Phlorotannin content and antioxidant activities extracted from Sargassum serratum was depended on the extracting conditions. The condition of extraction for antioxidant phlorotannin and the chemical composition of extract was determined. Brown algae Sargassum serratum has high antioxidant phlorotannin content. A total of 6 compounds were identified from the extract of Sargassum serratum. [ABSTRACT FROM AUTHOR]

SUMMARY The effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of two Vietnamese brown algae, Sargassum mcclurei and S. oligocystum (Fucales), were determined by field and laboratory measurements. Dissolved oxygen sensors and pulse-amplitude modulated (PAM) fluorometry were used for the measurements of photosynthetic efficiency. A Diving-PAM revealed that underwater measurements of the effective quantum yield ( Φ PSII) of both species declined with increasing incident PAR, with minimum Φ PSII occurring during noon to early afternoon. Φ PSII recovered in the evening, indicating photo-adaptation to excessive PAR. In laboratory experiments, Φ PSII also decreased under continuous exposure to 1000 μmol photons m−2 s−1; and full recovery occurred after 12 h of dark acclimatization. The net photosynthesis - PAR experiments of S. mcclurei and S. oligocystum conducted at 28°C revealed that the net photosynthetic rate quickly increased at PAR below the saturation irradiance of 361 and 301 μmol photons m−2 s−1 and nearly saturated to maximum net photosynthetic rates of 385 and 292 μg O2 gww − 1 min−1 without photoinhibition, respectively. Gross photosynthesis and dark respiration experiments determined over a range of temperatures (12-40°C), revealed that the maximum gross photosynthetic rates of 201 and 147 μg O2 gww − 1 min−1 occurred at 32.9 and 30.7°C for S. mcclurei and S. oligocystum, respectively. The dark respiration rates increased exponentially over the temperature ranges examined. The estimated maximum value of the maximum quantum yield occurred at 19.3 and 20.0°C and was 0.76 and 0.74, respectively. Similar to the natural habitat of the study site, these two species tolerated the relatively high temperatures and broad range of PAR. The ability of these species to recover from exposure to high PAR is one of the mechanisms that allow them to flourish in the shallow water environment. [ABSTRACT FROM AUTHOR]

Sargassum swartzii is economically exploited in India for alginate production. Indiscriminate harvesting of S. swartzii in natural beds leads to fast depletion. For sustainable utilization of this alga, it is inevitable to undertake its mass cultivation. Therefore, investigations were undertaken to develop a technology that can boost cultivation of this important species. An attempt was made to optimize the culture conditions for developing zygote-derived germlings for artificial seed production through vegetative parts such as vesicles and tertiary leaves. Vesicles and tertiary leaves ( n = 90) were subjected to a range of irradiances (05, 25, and 45 μmol photons m s), salinity (15, 20, 25, 30, 35, 40, 45, 50, and 55 psu), and photoperiod (8:16, 10:14, 12:12, 14:8, and 16:8-h (L/D) regimes under 30-day culture. Maximum regeneration (%) of receptacle from vesicles and tertiary leaf was observed at an irradiance of 45 μmol photons m s, 35 psu salinity, and 12:12-h (L/D) photoperiod which appears to be the most optimal condition. Variations in receptacle regeneration through vesicles and tertiary leaves were highly significant under different irradiances, salinities, and photoperiods ( p < 0.05), and there were no significant differences between % regeneration of vesicles and tertiary leaves ( p > 0.05). Germlings development followed the eight nuclei, one egg pattern which is quite common in the Sargassaceae. Within a day, multicellular germlings were developed with a bunch of unicellular rhizoids from fertilized oospores through repeated cell divisions. These findings confirmed that vesicles and tertiary leaves can be used as seed stock for the development of artificial seed production in S. swartzii as they contain primordial tissue for receptacle development. [ABSTRACT FROM AUTHOR]

In general, epiphytes have detrimental effects on the growth of their basiphytes due to competition for light and nutrients. Therefore, basiphyte species must expend energy suppressing epiphytes. Some studies suggest that phlorotannins, i.e. brown algal polyphenols, prevent colonization by epiphytes, whereas others question their allelopathic function because there is not necessarily a negative correlation between epiphyte abundance and the phlorotannin content of the basiphyte algae. Various phlorotannin components are found in brown algal species, thus we hypothesized that the antifouling activities of polyphenolic compounds may differ and that the analysis of phlorotannin profiles could be useful for estimating their ecological functions. We surveyed the epiphyte richness in the apical portions of 373 thalli from 15 sargassacean species, demonstrating that the variation and abundance of epiphyte species differed remarkably among the basiphyte species. However, there was a weak negative correlation between the density and total phlorotannin content of the basiphyte algae in only one of the 18 epiphyte species. The interspecific differences in the phlorotannin profile were characterized by quantitative ¹H nuclear magnetic resonance spectroscopy (qNMR), and four major groups were categorized based on cluster and principal component analyses of polyphenolic signals in the qNMR spectra. The epiphyte Neosiphonia harveyi was more abundant on Sargassum hemiphyllum, S. patens and S. piluliferum than on other basiphyte species, and these three species were similar according to the cluster analysis. These results suggest that some phlorotannin components may be more effective for antifouling; thus interspecific differences in the phlorotannin profile could affect the variation and abundance of epiphytes. [ABSTRACT FROM AUTHOR]

Abstract: The current study investigated the anticancer properties of gold nanoparticles (SG-stabilized AuNPs) synthesized using water extracts of the brown seaweed Sargassum glaucescens (SG). SG-stabilized AuNPs were characterized by ultraviolet-visible spectroscopy, transmission and scanning electron microscopy, and energy dispersive X-ray fluorescence spectrometry. The SG-stabilized AuNPs were stable and small at 3.65 ± 1.69 nm in size. The in vitro anticancer effect of SG-stabilized AuNPs was determined on cervical (HeLa), liver (HepG2), breast (MDA-MB-231) and leukemia (CEM-ss) cell lines using fluorescence microscopy, flow cytometry, caspase activity determination, and MTT assays. After 72 h treatment, SG-stabilized AuNPs was shown to be significant (p < 0.05) cytotoxic to the cancer cells in a dose- and time-dependent manner. The IC50 values of SG-stabilized AuNPs on the HeLa, HepG2, CEM-ss, MDA-MB-231 cell lines were 4.75 ± 1.23, 7.14 ± 1.45, 10.32 ± 1.5, and 11.82 ± 0.9 ±g/mL, respectively. On the other hand, SG-stabilized AuNPs showed no cytotoxic effect towards the normal human mammary epithelial cells (MCF-10A). SG-stabilized AuNPs significantly (p < 0.05) arrest HeLa cell cycle at G2/M phase and significantly (p < 0.05) activated caspases-3 and -9 activities. The anticancer effect of SG-stabilized AuNPs is via the intrinsic apoptotic pathway. The study showed that SG-stabilized AuNPs is a good candidate to be developed into a chemotherapeutic compound for the treatment of cancers especially cervical cancer. [ABSTRACT FROM AUTHOR]

Sargassum swartzii , a marine brown algae with wide range of biological properties belongs to the family Sargassaceae . Bioactive fucoidan fractions (CFF, FF1 and FF2) were isolated from S. swartzii and characterized by linear gradient anion-exchange chromatography and FT-IR. The characterized fucoidan fractions contained mainly sugars, sulfate and uronic acid. In the present study, anti-HIV-1 property of the fucoidan fractions was investigated. Fraction FF2 was found to exhibit significant anti-HIV-1 activity at concentrations of 1.56 and 6.25 μg/ml as observed by >50% reduction in HIV-1 p24 antigen levels and reverse transcriptase activity. Fucoidan fractions have no cytotoxic effects on PBMCs at the concentration range of 1.56–1000 μg/ml. These results suggest that fucoidan fractions could have inhibitory activity against HIV and has potential as an anti-HIV-1 agent. [ABSTRACT FROM AUTHOR]

On the basis of literature data and new morphological and ecological studies, the reinstatement of species rank for the Black Sea endemic species Cystoseira bosphorica is proposed. Previously reduced to a simple form of the Mediterranean endemic species C. crinita, this member of the caespitose Cystoseira group without spinose-like appendages clearly differs from C. crinita by having the axes long with smooth and prominent apices, the branches with numerous and slightly prominent cryptostomates, the aerocysts frequent, large, oval to subconical-broader at the apex, with 2 or more apical outgrowths, and by the receptacles long, cylindrical-tuberculate, simple or bifid, with apices blunt bearing sometimes a short lateral sub-apical spine. The species that shares the greatest number of characters with C. bosphorica is not C. crinita but the Mediterranean endemic species C. barbatula; however, this latter species clearly differs from C. bosphorica by the constant absence of aerocysts, the filiform branches with prominent and spaced cryptostomates, and by the receptacles smaller, compact, simple, humpy and subulate with sometimes 1-2 long lateral spine-like appendages. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to study the effect of different levels of sea weed extract, growth regulators, pruning along with and without urea spray and chemical nutrients on pattern of vegetative flushing episodes and growth pattern of May-June, July-August and September-October flush in order to regulate the growth and health of plant and in turn to enhance blooming flushes yield in Kesar mango. The trial was conducted over two years from 2010 to 2012 on 16 years old Kesar mango trees. The selected shoots of mango Cv. Kesar were pruned back by 10cm with 2 percent urea spray during last week of May i.e. after harvest, The different doses of Paclobutrazol (@ 5g.a.i, 7.5g.a.i) was soil drenched and 6-BA (100 & 200ppm), sea weed extract (3 & 5 %), KNO3 (4 & 6 %) and CaNO3 (4 & 6 %) foliar spray efficacy on morphological characteristics of growth cycles (flushing episodes) was evaluated. 6-BA (100 ppm) exhibited maximum summer flush (May- June). However lower Sept-Oct flushing was achieved with PP333 (@ 7.5g.a.i) followed by 6-BA (200 ppm) and Sea weed Extract (5 & 3 %). CaNO3 (6 %) exhibited maximum mean length of flush, Sea weed Extract (3%) exhibited the minimum number of days for flush emergence and complete extension of vegetative growth with maximum number of flushes per shoot and maximum number of leaves per shoot with 6-BA (100 ppm). P333 (Cultar), 6-BA and Sea weed extract showing promising effect in reducing the September-October vegetative flush which have detrimental effect near flowering time. [ABSTRACT FROM AUTHOR]

The seaweed Sargassum hemiphyllum is widely distributed throughout the coastal waters of Asia and has high commercial value. In recent years, its natural biomass has declined due to over-exploitation and environmental pollution. To seek for a feasible way to culture this seaweed efficiently, we designed a simple long-line system in a shrimp pond for the culture during winter, and the growth and nutritional composition of the seaweed were examined. Results show that the culture system was durable and flexible allowing S. hemiphyllum to grow vertically off the muddy bottom of the pond. Although the length of pondcultured S. hemiphyllum was inhibited by water depth, the weight-specific growth rate ((1.65±0.17)%/d) was nearly three times higher than that of wild plants ((0.62±0.19)%/d). The crude protein (6.92%±0.88%) and ash content (21.52%±0.07%) of the pond-cultured seaweed were significantly lower than those of the wild plants (9.38%±0.43% and 26.93%±0.07%, respectively); however, crude fat (1.01%±0.04%) was significantly higher than that of the wild plants (0.87%±0.02%). In addition, the nutritional composition of both pond-cultured and wild S. hemiphyllum was comparable to or even higher than those of other common seaweeds being used as food and/or aquaculture fodder. Future studies shall be focused on the impact of environmental parameters on its growth and nutritional composition. [ABSTRACT FROM AUTHOR]

Abstract: Some seaweeds protect themselves physically or chemically against epiphytes, but this antifouling effect may differ among species. Abundance, size and fertility of epiphytic Neosiphonia harveyi growing on four sargassacean basiphytes (Myagropsis myagroides, Sargassum hemiphyllum, Sargassum patens and Sargassum siliquastrum) were examined for 1 year in Wakasa Bay, Japan. The mean density of N. harveyi was lowest on S. siliquastrum, whereas the mean length of N. harveyi was similar among the four basiphyte species. To elucidate the cause of different densities among the basiphytes, settlement rates of N. harveyi carpospores were compared among the different basiphytes under a culture condition. Although the initial number of attached carpospores was similar, the number of carposporelings attached S. siliquastrum fell significantly after six days of incubation. This suggests that the antifouling effect against N. harveyi functions after attachment of the epiphyte spores. SEM observation of the basiphyte blades showed more frequent and wider areas of cuticle peeling in S. siliquastrum, which may have caused the lower survival of N. harveyi. [Copyright &y& Elsevier]

Abstract: The alga Sargassum dentifolium (Turner) C. Agardh, belongs to Sargassaceae, is a brown seaweed in red sea shores in Egypt. This work aimed to extract different water-soluble polysaccharide extracts (E1, E2, and E3) from S. dentifolium and to investigate their protective effect against cyclophosphamide (CP)-induced genotoxicity. Mice bone marrow cells (BMCs) were collected and analyzed for the chromosomal aberration, micronucleated BMCs (MN-BMCs), the mitotic index, DNA fragmentation by comet assay, and histone deacetylases (HDACs), and radical scavenging capacity of extracts was evaluated by the oxygen radical absorbance capacity assay. The results indicated that E2 and E3 significantly inhibited CP-induced multiple chromosomal aberrations, where E1 and E3 significantly suppressed the number of CP-induced formation of tetraploidy. The extracts prohibited the cytotoxic effect of CP and recovered the mitotic activity, whereas E1 possessed the highest recovery and mitosis. In absence of MN, CP induced formation of bi- and poly-nucleated BMCs. E1 prohibited CP-induced formation of bi-nucleated BMCs, while E2 and E3 prohibited CP-induced formation of poly-nucleated BMCs. CP-induced MN-BMCs were accompanied with mono-, bi- and poly-nucleated cells. E1 and E3 remarkably suppressed mono-nucleated MN-BMCs, while E2 inhibited bi-nucleated MN-BMCs. All the extracts significantly inhibited the CP-induced formation of poly-nucleated MN-BMCs. CP-induced DNA fragmentation was inhibited by all extracts, where E1 was the strongest inhibitor as concluded from the comet tail moment. All the extracts were strong OHrs, while only E3 was ROOr. The results revealed a drastic decline in HDACs activity by E1 and E3. In conclusion, S. dentifolium polysaccharide extracts E1 and E3 possessed a potential anti-genotoxic and a promising anti-mutagenic activity. [Copyright &y& Elsevier]

Of four species of Sargassaceae, representing the genera Carpophyllum, Cystoseira, Landsburgia, and Sargassum, the intergenic spacer of the ribosomal cistron was amplified using a forward primer annealing at the 3′-end of the large subunit (LSU) of the ribosomal cistron and a reverse primer annealing at the 5S rRNA gene. The PCR products were cloned and the DNA sequences of multiple clones were determined. Almost each clone showed a unique DNA sequence. Intra-individual variation of this LSU-5S intergenic spacer was extremely high and was characterized by great length variation and a high number of short tandem repeats. Sequences were unalignable and therefore it was concluded that the LSU-5S intergenic spacer is unsuitable for phylogenetic and phylogeographic studies of sargassacean taxa. [ABSTRACT FROM AUTHOR]

Sargassum subgenus Phyllotricha currently includes seven species restricted to Australian and New Zealand coasts. A recent study of Cystoseira and other Sargassaceae genera based on mitochondrial 23S DNA and chloroplast-encoded psbA sequences resulted in the most widely distributed species of subgenus Phyllotricha, Sargassum decurrens, being transferred to the reinstated monospecific Sargassopsis Trevisan. The fate of the residual six Phyllotricha species, however, was not considered. The present study examines these Phyllotricha species, alongside other Sargassum subgenera, Sargassopsis, Sirophysalis trinodis (formerly Cystoseira trinodis) and the New Zealand endemic Carpophyllum Greville, using morphological evidence and the molecular phylogenetic markers cox3, ITS-2 and the rbcL-S spacer. Our results suggest both the genus Sargassum and Sargassum subgenus Phyllotricha are polyphyletic as currently circumscribed. Four S. subgen. Phyllotricha species, i.e. S. sonderi, S. decipiens, S. varians and S. verruculosum, form a monophyletic group sister to the genus Carpophyllum, and S. peronii is genetically identical to S. decurrens with regard to all three loci. We propose the resurrection of the genus Phyllotricha Areschoug, with type species Phyllotricha sonderi, and include the new combinations Phyllotricha decipiens, Phyllotricha varians and Phyllotricha verruculosum. Sargassum peronii, S. heteromorphum and S. kendrickii are transferred to Sargassopsis and Sargassum peronii is considered a synonym of Sargassopsis decurrens. [ABSTRACT FROM AUTHOR]

Sargassum C. Agardh is one of the morphologically most complex phaeophyceaen genera and represents the most species-rich genus of the brown algal order Fucales Bory de Saint-Vincent (Phaeophyceae). The genus' classification system dates back to the 19th century and is based on observed differences in macro-morphological characters. Those morphological characters may display important variation within individual species, and several authors have linked the taxonomic complexity of the genus to its highly polymorphic nature and phenotypic plasticity. Among the large choice of existing species and subspecies epithets (about 1000), identifying taxa accurately is a difficult task, often relying on authors' interpretation of short Latin diagnoses or descriptions published in local Floras. Recently, the study of individual species' morphological range and DNA phylogenies underlined inconsistencies within low taxonomic levels (sections, subsections, series and species groups). Results highlighted the weak taxonomic value of traditional characters used to classify species, and pointed out significant taxonomic issues. The four Sargassum subgenera ( S. subgen. Arthrophycus, Bactrophycus, Sargassum and Phyllotrichia) are now subdivided into a total of 12 sections and further subdivisions were abandoned. Two possible new sections need to be assessed. In the present paper, we raise the hypothesis that S. subgen. Arthrophycus could be merged to S. subgen. Bactrophycus, and that S. subgen. Phyllotrichia could be transferred to the recently reinstated genus Sargassopsis Trevisan. We also propose that two sections of the S. subgen. Bactrophycus: S. sect. Halochloa and Repentia be merged. A summary of the actual classification is given along with an identification key for Sargassum subdivisions. [ABSTRACT FROM AUTHOR]

Abstract: Herpes simplex viruses (HSVs) display affinity for cell-surface heparan sulfate proteoglycans with biological relevance in virus entry. Here, we exploit an approach to inhibiting HSV infection by using a sulfated fucoidan, and a guluronic acid-rich alginate derived from Sargassum tenerrimum, mimicking the active domain of the entry receptor. These macromolecules have apparent molecular masses of 30±5 and 26±5kDa, respectively. They and their chemically sulfated derivatives showed activity against herpes simplex virus type 1 (HSV-1). Their inhibitory concentration 50% (IC50) values were in the range 0.5–15μg/ml and they lacked cytotoxicity at concentrations up to 1000μg/ml. The anti-HSV activity increased with increasing sulfate ester content. Our results suggest the feasibility of inhibiting HSV infection by blocking viral entry with polysaccharide having specific structure. [Copyright &y& Elsevier]

Sargassum thunbergii(Mertens ex Roth) Kuntze is a common brown seaweed in rocky intertidal zones along the northwestern Pacific coast. In the present study, we sequenced and annotated the complete mitochondrial genome ofS. thunbergii. The circularS. thunbergiimitogenome is 34,748 bp in size and contains the same set of 65 genes as other mtDNAs in fourSargassumspecies. The genome organization including the gene order, overlapping regions between genes and the total length of inter-genic regions is highly similar to the otherBactrophycusspecies. The comparison by genome scale alignment displays only minor differences in gene lengths, but higher divergence in inter-genic spacer regions, especially thecox3-atp6inter-genic spacer. Mitochondrial phylogenomics suggests thatS. thunbergiiis tightly combined withSargassum muticumandSargassum hemiphyllumforming the sect.Teretiaclade with strong support values (NJ/ML, 100%). The present data illustrate that the complete mtDNAs could provide a more complete assessment of their phylogenetic relationships. [ABSTRACT FROM AUTHOR]

Sargassum fusiforme(Harvey) Setchell (=Hizikia fusiformis(Harvey) Okamura) is one of the most important economic seaweeds for mariculture in China. In this study, we present the complete mitochondrial genome ofS. fusiforme. The genome is 34,696 bp in length with circular organization, encoding the standard set of three ribosomal RNA genes (rRNA), 25 transfer RNA genes (tRNA), 35 protein‐coding genes, and two conserved open reading frames (ORFs). Its total AT content is 62.47%, lower than other brown algae exceptPylaiella littoralis. The mitogenome carries 1571 bp of intergenic region constituting 4.53% of the genome, and 13 pairs of overlapping genes with the overlap size from 1 to 90 bp. The phylogenetic analyses based on 35 protein‐coding genes reveal thatS. fusiformehas a closer evolutionary relationship withSargassum muticumthanSargassum horneri, indicatingHizikiaare not distinct evolutionary entity and should be reduced to synonymy withSargassum. [ABSTRACT FROM AUTHOR]

The effects of different conditioning treatments (fresh, freezing, freeze-drying, oven-drying and greenhouse-drying) on the total phenolic content (TPC) and antioxidant activities of two brown algae, Sargassum muticum and Bifurcaria bifurcata, were investigated and compared. Phenolic compounds were extracted in a methanol/water (50:50) solution, and TPC was measured by the colorimetric Folin-Ciocalteu assay. Antioxidant activity was assessed by the DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging assay and the β-carotene bleaching method. The dried seaweeds showed lower phenolic contents and lower antioxidant capacities than the fresh and frozen ones, which suggests that the phenolic content and antioxidant activities are decreased by the drying treatments, especially, oven- and greenhouse-drying. Relationships between TPC, antioxidant properties and conditioning treatments are discussed. [ABSTRACT FROM AUTHOR]

Abstract  The invasive marine macroalga Sargassum muticum was recorded from Kilmore Quay, Co. Waterford, for the first time in the Republic of Ireland in 2001. It was found at several other places in that year and in subsequent years. An intensive survey was carried out from April 2003 to November 2003 to map the geographical distribution and spread of this invasive brown macroalga, and data on distribution were collected in subsequent years through 2006. This study indicated that S. muticum most probably arrived in the early or mid 1990s and has spread all around the Irish coastline colonising Co. Donegal for the first time in 2006. The results indicate that spreading is facilitated by boating and perhaps via shellfish transport. A rough rate of spread of 2–3 km year−1 has been calculated within one bay and for the Irish coastline of about 54 km year−1. Observations showed that S. muticum has been found growing in seagrass beds and in rock pools, which might have serious consequences for the biodiversity in rock pools and for the protective status of seagrass habitats. It is recommended that monitoring of S. muticum should continue, especially in areas of high amenity value and economic importance in order to observe possible effects on local flora and fauna, aquaculture, the seaweed industry and tourism. [ABSTRACT FROM AUTHOR]

Abstract  Ten species of Sargassum (Sargassaceae, Phaeophyceae) were found along the Gulf of Thailand. Morphological characteristics of Sargassum baccularia (Mertens) C.A. Agardh, S. binderi Sonder, S. cinereum J.G. Agardh, S.crassifolium J.G. Agardh, S. longifructum Tseng et Lu, S. oligocystum Montagne, S. polycystum C.A. Agardh, S. siliquosum J.G. Agardh, S. swartzii (Turner) C.A. Agardh and one unidentified species were examined and are described in detail. The most common species were S. polycystum distributed widely in almost all the study sites, S. crassifolium restricted to Prachuap Khirikhan Province, S. longifructum restricted to Chumphon Province, S. siliquosum restricted to Surat Thani Province and one unidentified species restricted to Songkhla Province. Three species (S. cinereum, S. longifructum and S. swartzii) are new records for the algal flora of Thailand. Five species (S. baccularia, S. cinereum, S. longifructum, S. polycystum and the unidentified species) belong to the section Zygocarpicae (J.G. Agardh) Setchell. [ABSTRACT FROM AUTHOR]