Brown algae is one of the three major types of marine algae and includes approximately 2000 species.It is widely dis-tributed in various seas around the world.Brown algae contain a plethora of active substances,such a...Brown algae is one of the three major types of marine algae and includes approximately 2000 species.It is widely dis-tributed in various seas around the world.Brown algae contain a plethora of active substances,such as polysaccharides,polyphe-nols,omega-3 fatty acids,and carotenoids.Laminarin,a type of storage carbohydrate found abundantly in brown algae,is mainly formed by glucose monomers linked byβ-1,3-glucosidic bonds and partialβ-1,6-glucosidic bonds.Laminarin and laminarin oligo-saccharides,which contain 2-10 saccharide units,have extensive biological activities,such as antitumor,antioxidant,anti-inflam-matory,and prebiotic properties.Moreover,both laminarin and laminarin oligosaccharides can be considered as ideal substrates for bioethanol production because they are composed of abundant glucose residues.Therefore,brown algae-derived laminarin and lami-narin oligosaccharides have various potential applications in the food,medicine,cosmetics,and bioenergy fields.This paper reviews the preparation methods of laminarin and laminarin oligosaccharides,as well as their biological activities and potential applications.展开更多
The chloroplast and mitochondrion of brown algae （Class Phaeophyceae of Phylum Ochrophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their e...The chloroplast and mitochondrion of brown algae （Class Phaeophyceae of Phylum Ochrophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lineages by using algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Kingdom Chromista. We have found that there is a split between Class Phaeophyceae of Phylum Ochrophyta and the others （Phylum Cryptophyta and Haptophyta） in Kingdom Chromista, and identified more diversity in chloroplast genes than mitochondrial ones in their phylogenetic trees. Taxonomy resolution for Class Phaeophyceae showed that it was divided into Laminariales-Ectocarpales clade and Fucales clade, and phylogenetic positions of Kjellmaniella crassi-folia, Hizikia fusifrome and Ishige okamurai were confirmed. Our analysis provided the basic phylogenetic relationships of Chromista algae, and demonstrated their potential ability to study endosymbiotic events.展开更多
Seaweeds are one of the largest producers of biomass in the marine environment. It has been well known that marine algae, especially brown algae was a rich source of biogeinc compounds with antifouling potential that ...Seaweeds are one of the largest producers of biomass in the marine environment. It has been well known that marine algae, especially brown algae was a rich source of biogeinc compounds with antifouling potential that could be ideal alternatives of tributyltin （TBT）. In this paper, antifouling potential of the brown algae Laminaria ＇sanhai＇ was explored. Firstly, the dried alga was extracted and the antialgal and antilarval activities were investigated. The EC50 and LC50 values of crude extract of Laminaria ＇sanhai＇ against diatom （Skeletonema costatum） and barnacle larval （Chthamalus challengeri） were 8.9 μg·mL -1 and 12.0 μg·mL -1 respectively. Then, guided by bioassay, the bioactive substances were isolated by liquid-liquid extraction. The antialgal and antilarval activities of isolated fraction were improved with the EC50 value of 7.4 μg· mL -1 against S. costatum and LC50 value of 9.7 μg mL 1 against C. challengeri larvae. Identification by IR, Q-TOFMS and GC-MS of the isolated bioactive substances revealed the abundance of fatty acids. These fatty acids, most with 16, 18 or 20 carbon atoms, contained myristic, hexadecanoic, oleic, linolenic, arachidonic and eicosapentaenoic acids. The results indicated that both the crude extract and the isolated bioactive substances had high antialgal and antilarval activities with no highlighted cytotoxicity which made the brown algae Laminaria ＇sanhai＇ a promising source of the environmentally friendly antifoulants.展开更多
Eight species of brown algae(Phaeophyceae)from the coast of Madagascar have been investigated for their chemical constituents.Fucosterol(3)was obtained as the most abundant compound.The brown alga Sargassum ilicifoliu...Eight species of brown algae(Phaeophyceae)from the coast of Madagascar have been investigated for their chemical constituents.Fucosterol(3)was obtained as the most abundant compound.The brown alga Sargassum ilicifolium was the source for the first isolation of the terpenoid C27-alcohol 1,10,2-trinorsqualenol(1)from marine sources.From S.incisifolium we isolated the highly unsaturated glycolipid 1-O-palmitoyl-2-O-stearidonoyl-3-O-β-D-galactopyranosylglycerol(4)and we report the first full assignment of its ^(1)H and ^(13)C NMR data.Apo-90-fucoxanthinone(8)along with 24-ketocholesterol(5),(22E)-3b-hydroxycholesta-5,22-dien-24-one(6),and saringosterol(7)were obtained from Turbinaria ornata.The crude extracts of all eight species of brown algae exhibited a pronounced antimicrobial activity against the Gram-positive bacteria Bacillus cereus,Staphylococcus aureus,and Streptococcus pneumoniae.展开更多
<div style="text-align:justify;"> According to the content of heavy metals Fe, Mn, Cu, Zn, Pb, Cd and Ni in brown algae <em>Sargassum miyabei</em> from the Peter the Great Bay of the Sea of...<div style="text-align:justify;"> According to the content of heavy metals Fe, Mn, Cu, Zn, Pb, Cd and Ni in brown algae <em>Sargassum miyabei</em> from the Peter the Great Bay of the Sea of Japan, geochemical factors were calculated. The algae geochemical anomaly index (I<sub>GA</sub>) characterizes the degree of excess of the background concentrations of metals. The heavy metal pollution factor (F<sub>p</sub>) is used to estimate the degree of pollution of the marine environment with heavy metals. The Peter the Great Bay has a low level of heavy metal pollution, but some parts of second-order bays, such as Amurskii Bay, Ussuriiskii Bay and Vostok Bay, have a moderate degree of pollution. The high pollution level was registed on the western coast of the Ussuriiskii Bay near the Vladivostok city landfill. Thirty percent of sampling stations were noted to have higher threshold levels of metals in the algae. These areas need to be monitored to assess their environmental status and measures should be applied to reduce the impact on the environment. </div>展开更多
The antioxidant activity of the phlorotannins extracted from five marine algaespecies(Saccharina latissima,Alaria esculenta,Laminaria digitata,Fucus vesiculosusand Ascophyllum nodosum)was studied.Three phlorotannin gr...The antioxidant activity of the phlorotannins extracted from five marine algaespecies(Saccharina latissima,Alaria esculenta,Laminaria digitata,Fucus vesiculosusand Ascophyllum nodosum)was studied.Three phlorotannin groups,including soluble,membrane-bound,and extracted membrane-bound phlorotannins obtained by two solvent extraction methods were investigated for their DPPH radical scavenging activity.F.vesiculosusand A.nodosumshowed the highest phlorotannin yield(14.83 mg-extract/g-algae and 12.80 mg-extract/g-algae,respectively)among the five algaespecies.Their soluble phlorophannin(SP),membrane-bound phlorotannin(MP)and extracted membrane-bound phlorotannin(eMP)extracts all showed equal or greater DPPH radical scavenging activity than the commercial antioxidants of butylated hydroxytoluene and ascorbic acid.The antioxidant potential that combines phlorotannin yield and antioxidant activity of the MP extracts of F.vesiculosusand A.nodosum(5890mL/g and 5278 mL/g algae,respectively)were higher than those of SP and eMP,suggesting that the MPs of F.vesiculosusand A.nodosumhad great potential to be used as antioxidants.Different extraction methods also showed significantly different effects on the antioxidant activity of the phlorotannin extracts.展开更多
Most phaeophytes （brown algae） and rhodophytes （red algae） dwell exclusively in marine habitats and play important roles in marine ecology and biodiversity. Many of these brown and red algae are also important res...Most phaeophytes （brown algae） and rhodophytes （red algae） dwell exclusively in marine habitats and play important roles in marine ecology and biodiversity. Many of these brown and red algae are also important resources for industries such as food, medicine and materials due to their unique metabolisms and me-tabolites. However, many fundamental questions surrounding their origins, early diversification, taxonomy, and special metabolisms remain unsolved because of poor molecular bases in brown and red algal study. As part of the 1 000 Plant Project, the marine macroalgal transcriptomes of 19 Phaeophyceae species and 21 Rhodophyta species from China＇s coast were sequenced, covering a total of 2 phyla, 3 classes, 11 orders, and 19 families. An average of 2 Gb per sample and a total 87.3 Gb of RNA-seq raw data were generated. Approxi-mately 15 000 to 25 000 unigenes for each brown algal sample and 5 000 to 10 000 unigenes for each red algal sample were annotated and analyzed. The annotation results showed obvious differences in gene expres-sion and genome characteristics between red algae and brown algae;these differences could even be seen between multicellular and unicellular red algae. The results elucidate some fundamental questions about the phylogenetic taxonomy within phaeophytes and rhodophytes, and also reveal many novel metabolic pathways. These pathways include algal CO2 fixation and particular carbohydrate metabolisms, and related gene/gene family characteristics and evolution in brown and red algae. These findings build on known algal genetic information and significantly improve our understanding of algal biology, biodiversity, evolution, and potential utilization of these marine algae.展开更多
In this study, variations in composition and properties of polysaccharides isolated from brown algae Costaria costata were analyzed. The algae were collected from May to July of the harvest period. The carbohydrates a...In this study, variations in composition and properties of polysaccharides isolated from brown algae Costaria costata were analyzed. The algae were collected from May to July of the harvest period. The carbohydrates alginate and fucoidan were extracted with selected solvents. 1H Nuclear magnetic resonance and rheology were used to investigate the monomer composition and rheological characteristics of alginate. Gas chromatography and Fourier transform-infrared spectroscopy were employed to investigate the compositional properties of purified fucoidan. The results indicated that the composition and properties of alginate and fucoidan varied during the life of this alga. The alginate from the alga harvested in May and June had a higher molecular weight, viscosity, and proportion of mannuronic acid, whereas that harvested in July had a lower molecular weight and viscosity but a higher proportion of guluroinc acid. The alginate from C. costata had a higher molecular weight and a different mannuronic acid： guluronic acid ratios compared with other algae; thus, it could be used in the chemical, food, cosmetics, and pharmaceutical industries. Fucoidan content reached the maximum in June. Substantial changes in the molecular weight distribution, monosaccharide composition, and sulfate content occurred simultaneously. The fraction of fucose in the polysaccharides decreased significantly from June to July, whereas that of mannose increased. This alga can be harvested during different growth periods to obtain fucoidans and alginates with different compositions and, therefore, with different biological properties.展开更多
A novel bromophenol was isolated from ethanolic extract of the brown alga Leathesia nana S.et G. The structure was elucidated as (E)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-2-methyl-propenal by spectroscopic methods inclu...A novel bromophenol was isolated from ethanolic extract of the brown alga Leathesia nana S.et G. The structure was elucidated as (E)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-2-methyl-propenal by spectroscopic methods including IR, HREIMS, 1D and 2D NMR techniques.展开更多
A new sesquiterpene-substituted benzoic acid has been isolated from the brown Alga Dictyopteris divaricata Okam.. Its structure was elucidated as 3-[(2-hydroxy-2,5,5,8a-tetra- methyldecahydro-1-naphthalenyl)methyl]-4...A new sesquiterpene-substituted benzoic acid has been isolated from the brown Alga Dictyopteris divaricata Okam.. Its structure was elucidated as 3-[(2-hydroxy-2,5,5,8a-tetra- methyldecahydro-1-naphthalenyl)methyl]-4-hydroxybenzoic acid, named dictyvaric acid on the basis of spectroscopic methods including IR, HRFABMS, 1D and 2D NMR techniques.展开更多
Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic ...Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr（VI）,Cr（III）,Pb（II） and Cd（II） by algal biomass obtained from algae Sargassum wightii（brown） and Caulerpa racemosa（green）.Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr（VI）,Cr（III）,Pb（II） and Cd（II） ions.C.racemosa exhibited 85% biosorption of Cd（II） and Cr（VI）,and 50% biosorption of Cr（III） and Pb（II）.The results of our study suggest that seaweed biomass can be used efficiently for展开更多
Long non-coding RNAs(lncRNAs)regulate a variety of biological processes,including sexual reproduction and differentiation.Saccharina japonica,a commercially important brown alga in China,shows remarkable sexual dimorp...Long non-coding RNAs(lncRNAs)regulate a variety of biological processes,including sexual reproduction and differentiation.Saccharina japonica,a commercially important brown alga in China,shows remarkable sexual dimorphism in haploid gametophytes.The sex of Saccharina japonica gametophytes is determined by UV sexual system.However,no results have been reported on the lncRNAs involved in the sex-related gene regulation of S.japonica.This study identified a number of lncRNAs and assessed their expression levels in male and female gametophytes.Among them,a total of 405 lncRNAs and 211 mRNAs showed differential expressions.Furthermore,the functions of target genes of differentially expressed lncRNAs(DELs)differed from those of differentially expressed genes(DEGs),suggesting that lncRNA may interact with other functional proteins,in addition to DEGs,to involve sex regulation in S.japonica.There were 32 and 90 potential cis-regulatory and trans-regulatory interactions between DELsDEGs,respectively.Five of these lncRNAs(LNC_002974,LNC_021059,LNC_038466,LNC_051584,and LNC_027400)interacted with putative male sex determination region(SDR)genes,suggesting that they act as regulators in gametophytes'sex regulation potentially.Findings from this study contribute to our understanding of the roles of lncRNAs in sex differentiation and lay the foundation for functional studies of candidate lncRNAs in the future.展开更多
Gold nanoparticles recently showed great interest for many uses including food, drug and medical applications. The algae </span><i style="font-family:"white-space:normal;">Undaria</i...Gold nanoparticles recently showed great interest for many uses including food, drug and medical applications. The algae </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> well known as wakame in South Asia are considered to be large edible brown algae. It provides nutritious source of dietary fiber, vitamin Bs and mineral. The present study aimed to investigate the use of </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> for green synthesis of metallic gold nanoparticles. The synthesized nanoparticles were characterized for physicochemical properties including size measurement and tested </span><i style="font-family:"white-space:normal;">in</i><span style="font-family:"white-space:normal;"> <i>vitro</i></span><span style="font-family:"white-space:normal;"> for their effect on viability of human non-small lung cancer H-460 cell line using the MTT assay. From the results, brown algae were able to chemically form nanoparticles with chloroauric acid solution possibly due to the sulphated polysaccharides found in algae. The particle sizes were found to be approximately 10 nm. The gold nanoparticles stabilized by the algae could decrease the cancer cell viability. However, the properties and biological activity of nanoparticles seemed to depend upon reaction time and temperature. Conclusively, gold nanoparticles synthesized and stabilized by the algae could decrease the cancer cell viability, thus indicating the potential of such nanoparticles for further study for anticancer activity.展开更多
AIM: Sargassum wightii Greville is a marine brown alga belonging to the Sargassaceae family which has about 200 species. The ethanolic extract of the whole dry plant powder contained numerous phytoconstituents, includ...AIM: Sargassum wightii Greville is a marine brown alga belonging to the Sargassaceae family which has about 200 species. The ethanolic extract of the whole dry plant powder contained numerous phytoconstituents, including flavonoids. The study was focused on the anticancer activity of Sargassum wightii in mice. METHOD: The ethanolic extract of Sargassum wightii(EESW) at two dose levels was used to examine the anticancer activity in mice using DAL cell lines to induce cancer. The body weight, viable and non-viable tumor cell count, mean survival time, increase in life span, and hematological parameters were observed for anticancer activity of EESW. RESULTS: The intraperitoneal inoculation of DAL cells in mice significantly increased cancer cell count. The decrease in the cancer cell number observed in the EESW-treated group cancer animals indicates that the test drug has a significant inhibitory effect on the tumor cell proliferation. Treatment with EESW also showed a significant decrease in tumor weight, and hence increased the lifespan of DAL-treated mice. In addition, EESW administration significantly restored the hematological parameters in DAL-treated mice. CONCLUSION: The present study results suggest that administration of extract offers enhanced antioxidant potential. Therefore it can be concluded from this study that EESW possesses anticancer activity.展开更多
Freshwater brown algae have been acknowledged as the least diverse of all groups of freshwater algae. Morphological and molecular investigation were conducted on a freshwater brown alga collected in this study. Morpho...Freshwater brown algae have been acknowledged as the least diverse of all groups of freshwater algae. Morphological and molecular investigation were conducted on a freshwater brown alga collected in this study. Morphological characterization and phylogenetic tree based on the rbcL gene confirmed its attribution to Heribaudiella fluviatilis. The complete organelle genomes of H. fluviatilis were determined and assembled from high-throughput sequencing. A circular tetrad structure of 128,880 bp was identified for the chloroplast, and the mitochondrial genome was assembled as a circle with 43,657 bp in length. This study provides the first and only record of organelle genomic information of the freshwater Phaeophyceae, which are important for understanding the endosymbiosis theories. Concatenated (Bayesian inference, maximum likelihood under MFP and GHOST models) and coalescent methods were used to construct the phylogenetic relationship among secondary plastid-bearing lineages based on organelle genomes. Obvious conflicts were observed in grouping relationships of chloroplast and mitochondrial genomes, even among different evolutionary models and tree-constructing methods. The transcriptome of H. fluviatilis was sequenced and used to construct the phylogenetic relationship among secondary plastid-bearing lineages. The phylogenetic relationships in nuclear and mitochondrial genomes were consistent in grouping CHSR taxa (cryptophytes, haptophytes, stramenopiles and rhizarians) in an independent branch. The phylogenetic relationship constructed from nuclear transcriptomes was highly reliable by owning robust supporting values on each node and was consistent with the serial endosymbiosis theory on evolution of red secondary plastid-derived lineages.展开更多
Water production in petroleum reservoirs poses considerable challenges, such as lower production efficiency, higher operational costs, and severe environmental risks. This study investigates the effectiveness of a nov...Water production in petroleum reservoirs poses considerable challenges, such as lower production efficiency, higher operational costs, and severe environmental risks. This study investigates the effectiveness of a novel, sustainable, and economical alginate-based gel system derived from Persian Gulf brown algae in decreasing reservoir rock water permeability. The ultrasonic-assisted method retrieved the most alginate, yielding 56% at a p H, alginate-to-water ratio, sonication time, and ultrasound power of11, 10 g/L, 45 min, and 75 W, respectively. The FTIR spectrum showed that the alginate structure had O-H, C-H, C=C, and C-O functional groups. Also, TGA results indicate that the extracted alginate is thermally stable. The effects of polymer concentration, cross-linker content, p H, temperature, and solvent salinity on the properties of the natural gel system were investigated. While the gel strength rose with increasing polymer and cross-linker concentrations, the gelation time decreased. Also, increasing the acidity of the system resulted in higher gel viscosity, attributed to stronger molecular binding.Seawater-based gels exhibited greater strength than distilled water gels due to divalent ions(Mg2+, Ca2+)in seawater. The sand-pack experiments demonstrated the ability of the polymer-gel system, which included 3 wt% of the alginate polymer and 1 wt% of Ca Cl2, to reduce permeability by 44.7%. Furthermore, the coreflood experiments conducted on a carbonate reservoir rock demonstrated the feasibility of in-situ gel formation and a 22.7% reduction in permeability by injecting a 0.5 wt% alginate solution. The results showed that the sustained gel functioned as a blocking agent by significantly diminishing the water permeability.展开更多
The potential of the methanolic extract of the seaweed,Sargassum polycystum in the synthesis of silver nanoparticles was investigated.The extract synthesized appreciable quantities of silver nanoparticles of the size ...The potential of the methanolic extract of the seaweed,Sargassum polycystum in the synthesis of silver nanoparticles was investigated.The extract synthesized appreciable quantities of silver nanoparticles of the size 5-7 nm,in 24 hrs.The particles were characterized by UV-Vis,FT-IR spectroscopy,HRTEM and XRD analysis.The results indicated that the algal extract can be utilized as an eco-friendly system for the synthesis of silver nanoparticles for various applications in the field of medicine.The methanolic extract of the alga,silver nitrate solution and their combination were tested for their antimicrobial activities against Pseudomonas aeruginosa,Klebsiella pneumoniae,Escherichia coli and Staphylococcus aureus.Anticancer activity of the extract and the silver nanoparticles were evaluated against the breast cancer line MCF-7.Active compounds in the crude extract of the alga were separated and identified as fatty acids by GC-MS analysis.These fatty acids together with the silver nanoparticles exhibited anticancer activity against the breast cancer cell line MCF-7.Results are presented and discussed in detail.展开更多
Sargassum vachellianum is an ecologically important brown alga.It is China-specific and mainly inhabits in rocky intertidal zones in southeast coastal waters of China.In this study,we sequenced its circular complete c...Sargassum vachellianum is an ecologically important brown alga.It is China-specific and mainly inhabits in rocky intertidal zones in southeast coastal waters of China.In this study,we sequenced its circular complete chloroplast genome(cpDNA)and compared it with cpDNAs from S.vachellianum,S.horneri and S.thunbergii.The complete S.vachellianum cpDNA was 124,582 bp in length and consisted of a pair of inverted repeats(IRs)of 5435 bp,a large single copy(LSC)region of 73,721 bp and a small single copy(SSC)region of 39,991 bp.Totally 160 genes were predicted,including 132 protein-coding genes,four ribosomal RNA genes and 24 tRNA genes,and the coding sequences contributed 77.48%of the whole genome.In addition,25 SSR loci and 28 highly variable regions were identified from the S.vachellianum cpDNA,which might be used as candidates for developing DNA barcode markers of Sargassum species.The phylogenetic tree based on datasets of all the plastid-encoded proteins demonstrated that species of S.subgenus Bactrophycus were firstly combined and then clustered with S.vachellianum,which belongs to S.subgen.Sargassum.The results indicate that the chloroplast genomes are good resources for developing new DNA markers for taxonomy,and also as tools for evolutionary research of closely related species in future studies.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.31922072)National Key Research and Development Program of China(Nos.2019YFD0901902 and 2019YFD0901904)+1 种基金Taishan Scholar Project of Shandong Province(No.tsqn201812020)the Fundamental Research Funds for the Central Universities(No.201941002).
文摘Brown algae is one of the three major types of marine algae and includes approximately 2000 species.It is widely dis-tributed in various seas around the world.Brown algae contain a plethora of active substances,such as polysaccharides,polyphe-nols,omega-3 fatty acids,and carotenoids.Laminarin,a type of storage carbohydrate found abundantly in brown algae,is mainly formed by glucose monomers linked byβ-1,3-glucosidic bonds and partialβ-1,6-glucosidic bonds.Laminarin and laminarin oligo-saccharides,which contain 2-10 saccharide units,have extensive biological activities,such as antitumor,antioxidant,anti-inflam-matory,and prebiotic properties.Moreover,both laminarin and laminarin oligosaccharides can be considered as ideal substrates for bioethanol production because they are composed of abundant glucose residues.Therefore,brown algae-derived laminarin and lami-narin oligosaccharides have various potential applications in the food,medicine,cosmetics,and bioenergy fields.This paper reviews the preparation methods of laminarin and laminarin oligosaccharides,as well as their biological activities and potential applications.
基金The National Natural Science Foundation of China under contract Nos 31140070,31271397 and 41206116the algal transcrip-tome sequencing was supported by 1KP Project(www.onekp.com)
文摘The chloroplast and mitochondrion of brown algae （Class Phaeophyceae of Phylum Ochrophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lineages by using algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Kingdom Chromista. We have found that there is a split between Class Phaeophyceae of Phylum Ochrophyta and the others （Phylum Cryptophyta and Haptophyta） in Kingdom Chromista, and identified more diversity in chloroplast genes than mitochondrial ones in their phylogenetic trees. Taxonomy resolution for Class Phaeophyceae showed that it was divided into Laminariales-Ectocarpales clade and Fucales clade, and phylogenetic positions of Kjellmaniella crassi-folia, Hizikia fusifrome and Ishige okamurai were confirmed. Our analysis provided the basic phylogenetic relationships of Chromista algae, and demonstrated their potential ability to study endosymbiotic events.
基金supported by the National Natural Science Foundation of China(No.41376106)the National Key Research and Development Program(No.2016YFC1402101)the research program from National Marine Hazard Mitigation Service(No.2014AA060)
文摘Seaweeds are one of the largest producers of biomass in the marine environment. It has been well known that marine algae, especially brown algae was a rich source of biogeinc compounds with antifouling potential that could be ideal alternatives of tributyltin （TBT）. In this paper, antifouling potential of the brown algae Laminaria ＇sanhai＇ was explored. Firstly, the dried alga was extracted and the antialgal and antilarval activities were investigated. The EC50 and LC50 values of crude extract of Laminaria ＇sanhai＇ against diatom （Skeletonema costatum） and barnacle larval （Chthamalus challengeri） were 8.9 μg·mL -1 and 12.0 μg·mL -1 respectively. Then, guided by bioassay, the bioactive substances were isolated by liquid-liquid extraction. The antialgal and antilarval activities of isolated fraction were improved with the EC50 value of 7.4 μg· mL -1 against S. costatum and LC50 value of 9.7 μg mL 1 against C. challengeri larvae. Identification by IR, Q-TOFMS and GC-MS of the isolated bioactive substances revealed the abundance of fatty acids. These fatty acids, most with 16, 18 or 20 carbon atoms, contained myristic, hexadecanoic, oleic, linolenic, arachidonic and eicosapentaenoic acids. The results indicated that both the crude extract and the isolated bioactive substances had high antialgal and antilarval activities with no highlighted cytotoxicity which made the brown algae Laminaria ＇sanhai＇ a promising source of the environmentally friendly antifoulants.
文摘Eight species of brown algae(Phaeophyceae)from the coast of Madagascar have been investigated for their chemical constituents.Fucosterol(3)was obtained as the most abundant compound.The brown alga Sargassum ilicifolium was the source for the first isolation of the terpenoid C27-alcohol 1,10,2-trinorsqualenol(1)from marine sources.From S.incisifolium we isolated the highly unsaturated glycolipid 1-O-palmitoyl-2-O-stearidonoyl-3-O-β-D-galactopyranosylglycerol(4)and we report the first full assignment of its ^(1)H and ^(13)C NMR data.Apo-90-fucoxanthinone(8)along with 24-ketocholesterol(5),(22E)-3b-hydroxycholesta-5,22-dien-24-one(6),and saringosterol(7)were obtained from Turbinaria ornata.The crude extracts of all eight species of brown algae exhibited a pronounced antimicrobial activity against the Gram-positive bacteria Bacillus cereus,Staphylococcus aureus,and Streptococcus pneumoniae.
文摘<div style="text-align:justify;"> According to the content of heavy metals Fe, Mn, Cu, Zn, Pb, Cd and Ni in brown algae <em>Sargassum miyabei</em> from the Peter the Great Bay of the Sea of Japan, geochemical factors were calculated. The algae geochemical anomaly index (I<sub>GA</sub>) characterizes the degree of excess of the background concentrations of metals. The heavy metal pollution factor (F<sub>p</sub>) is used to estimate the degree of pollution of the marine environment with heavy metals. The Peter the Great Bay has a low level of heavy metal pollution, but some parts of second-order bays, such as Amurskii Bay, Ussuriiskii Bay and Vostok Bay, have a moderate degree of pollution. The high pollution level was registed on the western coast of the Ussuriiskii Bay near the Vladivostok city landfill. Thirty percent of sampling stations were noted to have higher threshold levels of metals in the algae. These areas need to be monitored to assess their environmental status and measures should be applied to reduce the impact on the environment. </div>
基金This work was financially supported by the start-up fund of North Carolina State University.
文摘The antioxidant activity of the phlorotannins extracted from five marine algaespecies(Saccharina latissima,Alaria esculenta,Laminaria digitata,Fucus vesiculosusand Ascophyllum nodosum)was studied.Three phlorotannin groups,including soluble,membrane-bound,and extracted membrane-bound phlorotannins obtained by two solvent extraction methods were investigated for their DPPH radical scavenging activity.F.vesiculosusand A.nodosumshowed the highest phlorotannin yield(14.83 mg-extract/g-algae and 12.80 mg-extract/g-algae,respectively)among the five algaespecies.Their soluble phlorophannin(SP),membrane-bound phlorotannin(MP)and extracted membrane-bound phlorotannin(eMP)extracts all showed equal or greater DPPH radical scavenging activity than the commercial antioxidants of butylated hydroxytoluene and ascorbic acid.The antioxidant potential that combines phlorotannin yield and antioxidant activity of the MP extracts of F.vesiculosusand A.nodosum(5890mL/g and 5278 mL/g algae,respectively)were higher than those of SP and eMP,suggesting that the MPs of F.vesiculosusand A.nodosumhad great potential to be used as antioxidants.Different extraction methods also showed significantly different effects on the antioxidant activity of the phlorotannin extracts.
基金The National Natural Science Foundation of China under contract Nos 31140070,31271397 and 41206116the algal transcrip-tome sequencing was supported by 1KP Project(www.onekp.com)
文摘Most phaeophytes （brown algae） and rhodophytes （red algae） dwell exclusively in marine habitats and play important roles in marine ecology and biodiversity. Many of these brown and red algae are also important resources for industries such as food, medicine and materials due to their unique metabolisms and me-tabolites. However, many fundamental questions surrounding their origins, early diversification, taxonomy, and special metabolisms remain unsolved because of poor molecular bases in brown and red algal study. As part of the 1 000 Plant Project, the marine macroalgal transcriptomes of 19 Phaeophyceae species and 21 Rhodophyta species from China＇s coast were sequenced, covering a total of 2 phyla, 3 classes, 11 orders, and 19 families. An average of 2 Gb per sample and a total 87.3 Gb of RNA-seq raw data were generated. Approxi-mately 15 000 to 25 000 unigenes for each brown algal sample and 5 000 to 10 000 unigenes for each red algal sample were annotated and analyzed. The annotation results showed obvious differences in gene expres-sion and genome characteristics between red algae and brown algae;these differences could even be seen between multicellular and unicellular red algae. The results elucidate some fundamental questions about the phylogenetic taxonomy within phaeophytes and rhodophytes, and also reveal many novel metabolic pathways. These pathways include algal CO2 fixation and particular carbohydrate metabolisms, and related gene/gene family characteristics and evolution in brown and red algae. These findings build on known algal genetic information and significantly improve our understanding of algal biology, biodiversity, evolution, and potential utilization of these marine algae.
基金supported by the Key Research and Development Program in Shandong Province(No.2016GSF121034)the National Science and Technology Pillar Program in the 12th Five Year Plan of China(No.2015BAD17B02)+1 种基金Open Foundation of the State Key Laboratory of Bioactive Seaweed Substancesthe Jiangsu Provincial Key R&D Project(No.BE2015335)
文摘In this study, variations in composition and properties of polysaccharides isolated from brown algae Costaria costata were analyzed. The algae were collected from May to July of the harvest period. The carbohydrates alginate and fucoidan were extracted with selected solvents. 1H Nuclear magnetic resonance and rheology were used to investigate the monomer composition and rheological characteristics of alginate. Gas chromatography and Fourier transform-infrared spectroscopy were employed to investigate the compositional properties of purified fucoidan. The results indicated that the composition and properties of alginate and fucoidan varied during the life of this alga. The alginate from the alga harvested in May and June had a higher molecular weight, viscosity, and proportion of mannuronic acid, whereas that harvested in July had a lower molecular weight and viscosity but a higher proportion of guluroinc acid. The alginate from C. costata had a higher molecular weight and a different mannuronic acid： guluronic acid ratios compared with other algae; thus, it could be used in the chemical, food, cosmetics, and pharmaceutical industries. Fucoidan content reached the maximum in June. Substantial changes in the molecular weight distribution, monosaccharide composition, and sulfate content occurred simultaneously. The fraction of fucose in the polysaccharides decreased significantly from June to July, whereas that of mannose increased. This alga can be harvested during different growth periods to obtain fucoidans and alginates with different compositions and, therefore, with different biological properties.
文摘A novel bromophenol was isolated from ethanolic extract of the brown alga Leathesia nana S.et G. The structure was elucidated as (E)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-2-methyl-propenal by spectroscopic methods including IR, HREIMS, 1D and 2D NMR techniques.
文摘A new sesquiterpene-substituted benzoic acid has been isolated from the brown Alga Dictyopteris divaricata Okam.. Its structure was elucidated as 3-[(2-hydroxy-2,5,5,8a-tetra- methyldecahydro-1-naphthalenyl)methyl]-4-hydroxybenzoic acid, named dictyvaric acid on the basis of spectroscopic methods including IR, HRFABMS, 1D and 2D NMR techniques.
文摘Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr（VI）,Cr（III）,Pb（II） and Cd（II） by algal biomass obtained from algae Sargassum wightii（brown） and Caulerpa racemosa（green）.Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr（VI）,Cr（III）,Pb（II） and Cd（II） ions.C.racemosa exhibited 85% biosorption of Cd（II） and Cr（VI）,and 50% biosorption of Cr（III） and Pb（II）.The results of our study suggest that seaweed biomass can be used efficiently for
基金supported by the National Natural Science Foundation of China(No.132072962)the Agricultural Industrial Technology System in Shandong Province(No.SDAIT-26)+3 种基金the‘First Class Fishery Discipline’Programme[(2020)3]in Shandong Provincethe Special Talent Programme‘Yishi Yiyi’in Shandong Province,Chinathe National Key R&D Program of China(No.2018YFD0901500)the Shandong Province Agriculture Seed Project(No.2021LZ GC004)。
文摘Long non-coding RNAs(lncRNAs)regulate a variety of biological processes,including sexual reproduction and differentiation.Saccharina japonica,a commercially important brown alga in China,shows remarkable sexual dimorphism in haploid gametophytes.The sex of Saccharina japonica gametophytes is determined by UV sexual system.However,no results have been reported on the lncRNAs involved in the sex-related gene regulation of S.japonica.This study identified a number of lncRNAs and assessed their expression levels in male and female gametophytes.Among them,a total of 405 lncRNAs and 211 mRNAs showed differential expressions.Furthermore,the functions of target genes of differentially expressed lncRNAs(DELs)differed from those of differentially expressed genes(DEGs),suggesting that lncRNA may interact with other functional proteins,in addition to DEGs,to involve sex regulation in S.japonica.There were 32 and 90 potential cis-regulatory and trans-regulatory interactions between DELsDEGs,respectively.Five of these lncRNAs(LNC_002974,LNC_021059,LNC_038466,LNC_051584,and LNC_027400)interacted with putative male sex determination region(SDR)genes,suggesting that they act as regulators in gametophytes'sex regulation potentially.Findings from this study contribute to our understanding of the roles of lncRNAs in sex differentiation and lay the foundation for functional studies of candidate lncRNAs in the future.
文摘Gold nanoparticles recently showed great interest for many uses including food, drug and medical applications. The algae </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> well known as wakame in South Asia are considered to be large edible brown algae. It provides nutritious source of dietary fiber, vitamin Bs and mineral. The present study aimed to investigate the use of </span><i style="font-family:"white-space:normal;">Undaria</i><span style="font-family:"white-space:normal;"> <i>sp.</i></span><span style="font-family:"white-space:normal;"> for green synthesis of metallic gold nanoparticles. The synthesized nanoparticles were characterized for physicochemical properties including size measurement and tested </span><i style="font-family:"white-space:normal;">in</i><span style="font-family:"white-space:normal;"> <i>vitro</i></span><span style="font-family:"white-space:normal;"> for their effect on viability of human non-small lung cancer H-460 cell line using the MTT assay. From the results, brown algae were able to chemically form nanoparticles with chloroauric acid solution possibly due to the sulphated polysaccharides found in algae. The particle sizes were found to be approximately 10 nm. The gold nanoparticles stabilized by the algae could decrease the cancer cell viability. However, the properties and biological activity of nanoparticles seemed to depend upon reaction time and temperature. Conclusively, gold nanoparticles synthesized and stabilized by the algae could decrease the cancer cell viability, thus indicating the potential of such nanoparticles for further study for anticancer activity.
文摘AIM: Sargassum wightii Greville is a marine brown alga belonging to the Sargassaceae family which has about 200 species. The ethanolic extract of the whole dry plant powder contained numerous phytoconstituents, including flavonoids. The study was focused on the anticancer activity of Sargassum wightii in mice. METHOD: The ethanolic extract of Sargassum wightii(EESW) at two dose levels was used to examine the anticancer activity in mice using DAL cell lines to induce cancer. The body weight, viable and non-viable tumor cell count, mean survival time, increase in life span, and hematological parameters were observed for anticancer activity of EESW. RESULTS: The intraperitoneal inoculation of DAL cells in mice significantly increased cancer cell count. The decrease in the cancer cell number observed in the EESW-treated group cancer animals indicates that the test drug has a significant inhibitory effect on the tumor cell proliferation. Treatment with EESW also showed a significant decrease in tumor weight, and hence increased the lifespan of DAL-treated mice. In addition, EESW administration significantly restored the hematological parameters in DAL-treated mice. CONCLUSION: The present study results suggest that administration of extract offers enhanced antioxidant potential. Therefore it can be concluded from this study that EESW possesses anticancer activity.
基金funded by the National Natural Science Foundation of China(No.31800172 to F.R.Nan,No.32170204 to S.L.Xie,No.32270220 and U22A20445 to J.Feng)the Excellent Achievement Cultivation Project of Higher education in Shanxi(No.2020KJ029).
文摘Freshwater brown algae have been acknowledged as the least diverse of all groups of freshwater algae. Morphological and molecular investigation were conducted on a freshwater brown alga collected in this study. Morphological characterization and phylogenetic tree based on the rbcL gene confirmed its attribution to Heribaudiella fluviatilis. The complete organelle genomes of H. fluviatilis were determined and assembled from high-throughput sequencing. A circular tetrad structure of 128,880 bp was identified for the chloroplast, and the mitochondrial genome was assembled as a circle with 43,657 bp in length. This study provides the first and only record of organelle genomic information of the freshwater Phaeophyceae, which are important for understanding the endosymbiosis theories. Concatenated (Bayesian inference, maximum likelihood under MFP and GHOST models) and coalescent methods were used to construct the phylogenetic relationship among secondary plastid-bearing lineages based on organelle genomes. Obvious conflicts were observed in grouping relationships of chloroplast and mitochondrial genomes, even among different evolutionary models and tree-constructing methods. The transcriptome of H. fluviatilis was sequenced and used to construct the phylogenetic relationship among secondary plastid-bearing lineages. The phylogenetic relationships in nuclear and mitochondrial genomes were consistent in grouping CHSR taxa (cryptophytes, haptophytes, stramenopiles and rhizarians) in an independent branch. The phylogenetic relationship constructed from nuclear transcriptomes was highly reliable by owning robust supporting values on each node and was consistent with the serial endosymbiosis theory on evolution of red secondary plastid-derived lineages.
文摘Water production in petroleum reservoirs poses considerable challenges, such as lower production efficiency, higher operational costs, and severe environmental risks. This study investigates the effectiveness of a novel, sustainable, and economical alginate-based gel system derived from Persian Gulf brown algae in decreasing reservoir rock water permeability. The ultrasonic-assisted method retrieved the most alginate, yielding 56% at a p H, alginate-to-water ratio, sonication time, and ultrasound power of11, 10 g/L, 45 min, and 75 W, respectively. The FTIR spectrum showed that the alginate structure had O-H, C-H, C=C, and C-O functional groups. Also, TGA results indicate that the extracted alginate is thermally stable. The effects of polymer concentration, cross-linker content, p H, temperature, and solvent salinity on the properties of the natural gel system were investigated. While the gel strength rose with increasing polymer and cross-linker concentrations, the gelation time decreased. Also, increasing the acidity of the system resulted in higher gel viscosity, attributed to stronger molecular binding.Seawater-based gels exhibited greater strength than distilled water gels due to divalent ions(Mg2+, Ca2+)in seawater. The sand-pack experiments demonstrated the ability of the polymer-gel system, which included 3 wt% of the alginate polymer and 1 wt% of Ca Cl2, to reduce permeability by 44.7%. Furthermore, the coreflood experiments conducted on a carbonate reservoir rock demonstrated the feasibility of in-situ gel formation and a 22.7% reduction in permeability by injecting a 0.5 wt% alginate solution. The results showed that the sustained gel functioned as a blocking agent by significantly diminishing the water permeability.
文摘The potential of the methanolic extract of the seaweed,Sargassum polycystum in the synthesis of silver nanoparticles was investigated.The extract synthesized appreciable quantities of silver nanoparticles of the size 5-7 nm,in 24 hrs.The particles were characterized by UV-Vis,FT-IR spectroscopy,HRTEM and XRD analysis.The results indicated that the algal extract can be utilized as an eco-friendly system for the synthesis of silver nanoparticles for various applications in the field of medicine.The methanolic extract of the alga,silver nitrate solution and their combination were tested for their antimicrobial activities against Pseudomonas aeruginosa,Klebsiella pneumoniae,Escherichia coli and Staphylococcus aureus.Anticancer activity of the extract and the silver nanoparticles were evaluated against the breast cancer line MCF-7.Active compounds in the crude extract of the alga were separated and identified as fatty acids by GC-MS analysis.These fatty acids together with the silver nanoparticles exhibited anticancer activity against the breast cancer cell line MCF-7.Results are presented and discussed in detail.
基金supported by Ocean Public Welfare Scientific Research Project(No.201405040)Shanghai Universities Plateau Discipline Project of Marine Sciences.
文摘Sargassum vachellianum is an ecologically important brown alga.It is China-specific and mainly inhabits in rocky intertidal zones in southeast coastal waters of China.In this study,we sequenced its circular complete chloroplast genome(cpDNA)and compared it with cpDNAs from S.vachellianum,S.horneri and S.thunbergii.The complete S.vachellianum cpDNA was 124,582 bp in length and consisted of a pair of inverted repeats(IRs)of 5435 bp,a large single copy(LSC)region of 73,721 bp and a small single copy(SSC)region of 39,991 bp.Totally 160 genes were predicted,including 132 protein-coding genes,four ribosomal RNA genes and 24 tRNA genes,and the coding sequences contributed 77.48%of the whole genome.In addition,25 SSR loci and 28 highly variable regions were identified from the S.vachellianum cpDNA,which might be used as candidates for developing DNA barcode markers of Sargassum species.The phylogenetic tree based on datasets of all the plastid-encoded proteins demonstrated that species of S.subgenus Bactrophycus were firstly combined and then clustered with S.vachellianum,which belongs to S.subgen.Sargassum.The results indicate that the chloroplast genomes are good resources for developing new DNA markers for taxonomy,and also as tools for evolutionary research of closely related species in future studies.
