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1.
Molecules ; 26(17)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34500650

RESUMO

Recent increased interest in seaweed is motivated by attention generated in their bioactive components that have potential applications in the functional food and nutraceutical industries. In the present study, nutritional composition, metabolite profiles, phytochemical screening and physicochemical properties of freeze-dried brown seaweed, Sargassum polycystum were evaluated. Results showed that the S. polycystum had protein content of 8.65 ± 1.06%, lipid of 3.42 ± 0.01%, carbohydrate of 36.55 ± 1.09% and total dietary fibre content of 2.75 ± 0.58% on dry weight basis. The mineral content of S. polycystum including Na, K, Ca, Mg Fe, Se and Mn were 8876.45 ± 0.47, 1711.05 ± 0.07, 1079.75 ± 0.30, 213.85 ± 0.02, 277.6 ± 0.12, 4.70 ± 0.00 and 4.45 ± 0.00 mg 100/g DW, respectively. Total carotenoid, chlorophyll a and b content in S. polycystum were detected at 45.28 ± 1.77, 141.98 ± 1.18 and 111.29 µg/g respectively. The total amino acid content was 74.90 ± 1.45%. The study revealed various secondary metabolites and major constituents of S. polycystum fibre to include fucose, mannose, galactose, xylose and rhamnose. The metabolites extracted from the seaweeds comprised n-hexadecanoic acid, 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester, benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy- methyl ester, 1-dodecanol, 3,7,11-trimethyl-, which were the most abundant. The physicochemical properties of S. polycystum such as water-holding and swelling capacity were comparable to several commercial fibre-rich products. In conclusion, results of this study indicate that S. polycystum is a potential candidate as functional food sources for human consumption and its cultivation needs to be encouraged.


Assuntos
Nutrientes/química , Feófitas/química , Compostos Fitoquímicos/química , Sargassum/química , Alga Marinha/química , Antioxidantes/química , Carotenoides/química , Clorofila A/química , Fibras na Dieta , Humanos , Malásia , Minerais/química , Extratos Vegetais/química , Verduras/química
2.
J Environ Manage ; 299: 113614, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34523542

RESUMO

The Mexican Caribbean is a vital nesting destination for loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles. Since 2015, massive periodical landings of pelagic Sargassum species (sargasso) have affected coastal ecosystems. Dense accumulations of sargasso on the shoreline may preclude access to sea turtles' preferred nesting areas and compromise hatching. In this study, we assess whether the number of nests and hatches of loggerhead and green sea turtles has been affected by the massive influx of sargasso. We compare data from before (2010-2014) and after (2015-2019) the first sargasso event, obtained from the same 17 marine turtle camps, which collectively account for 72.3 km of sampling distance over a 210 km section of shoreline. No differences in preferences on nesting beaches were recorded between periods for the two species. The mean number of nests per kilometer of coastline remained without statistically significant changes between periods in 16 camps and increased significantly in one camp for each species. Overall, the mean annual number of nests per kilometer of beach was 37% higher in the period after massive landings of sargasso began. The mean number of hatchlings increased significantly in one camp for C. mydas and in three for C. caretta. Periodical massive landings of sargasso from 2015 to 2019 do not appear to have compromised nesting and hatching of loggerhead and green sea turtles along the Mexican Caribbean coast.


Assuntos
Sargassum , Tartarugas , Animais , Região do Caribe , Ecossistema , Comportamento de Nidação
3.
Bioresour Technol ; 340: 125733, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34426234

RESUMO

This study deals with the multiproduct valorization of the invasive macroalgae Sargassum muticum within a green biorefinery concept using microwave hydrothermal treatment. Temperatures of 160 and 180 °C for 0-60 min (severities 1.62-3.54) were evaluated, allowing a recovery of a liquid phase rich in fucoidan-derived compounds (up to 4.81 g/L), oligomers and phenolics with antioxidant capacity (up to 2.85 g TE/L by ABTS assay), and a high-enzymatically susceptible solid (glucan to glucose conversion 76-100% in 9 h) suitable for bioethanol production (20.5 g/L in 18 h, corresponding to 96% ethanol yield). Moreover, energy consumption of the pretreatments' temperature-time binomial was evaluated showing significant differences, demonstrating the advantages of microwave as alternative heating pretreatment.


Assuntos
Sargassum , Alga Marinha , Etanol , Glucose , Micro-Ondas
4.
Nutrients ; 13(8)2021 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-34445047

RESUMO

Sargassum fusiforme alginate (SF-Alg) possess many pharmacological activities, including hypoglycemic and hypolipidemic. However, the hypoglycemic mechanisms of SF-Alg remain unclear due to its low bioavailability. In this study, we evaluated the therapeutic effect of SF-Alg on high-fat diet (HFD)/streptozotocin (STZ)-induced type 2 diabetes (T2D) mice. SF-Alg intervention was found to significantly reduce fasting blood glucose (FBG), triglycerides (TG), and total cholesterol (TC), while increasing high-density lipoprotein cholesterol (HDL-c) and improving glucose tolerance. In addition, administrating SF-Alg to diabetic mice moderately attenuated pathological changes in adipose, hepatic, and heart tissues as well as skeletal muscle, and diminished oxidative stress. To probe the underlying mechanisms, we further analyzed the gut microbiota using 16S rRNA amplicon sequencing, as well as metabolites by non-targeted metabolomics. Here, SF-Alg significantly increased some benign bacteria (Lactobacillus, Bacteroides, Akkermansia Alloprevotella, Weissella and Enterorhabdus), and significantly decreased harmful bacteria (Turicibacter and Helicobacter). Meanwhile, SF-Alg dramatically decreased branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) in the colon of T2D mice, suggesting a positive benefit of SF-Alg as an adjvant agent for T2D.


Assuntos
Alginatos/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/farmacologia , Sargassum/química , Animais , Glicemia/efeitos dos fármacos , Colesterol/sangue , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/etiologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etiologia , Dieta Hiperlipídica/efeitos adversos , Microbioma Gastrointestinal/efeitos dos fármacos , Hiperglicemia/sangue , Hiperglicemia/tratamento farmacológico , Hiperglicemia/etiologia , Camundongos , Estreptozocina , Triglicerídeos/sangue
5.
J Environ Manage ; 298: 113507, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34388546

RESUMO

Since 2014, Mexican Caribbean coasts have experienced an atypical massive arrival of pelagic Sargassum accumulated on the shores triggers economic losses, public health problems, and ecosystem damaging near the coastline. Mechanical harvesting has been implemented ending in landfills. Since Sargassum algae represent abundant biomass in tropical regions of the world, it has shown potential as a feedstock to supply bioprocesses focused on obtaining high-value compounds and bioproducts. Nevertheless, there is a lack of data on the biochemical composition of Sargassum biomass from Mexican Caribbean coasts to propose valorization pathways. This study conducted a biochemical and elemental characterization of Sargassum biomass and compared, through statistical analysis, the effect of the season (dry and wet), place of collection (from the beach and shallow water), and method of extraction (Microwave-Assisted Extraction and Enzyme Assisted Extraction) on biomass composition. The biomass composition, expressed in dry weight basis, revealed 5-7% moisture content, 24-31 % ash, 2.6-3.8 % lipids, 1.8-7.0 %, total carbohydrates, 3-11 % total proteins, 1.5-2.31 mgGAg-1 total phenolic compounds (TPC), 2.7-2.9 kcal g-1 calorific power, and metals such as As (30-146.3 ppm), Fe (16.5-45 ppm), P (197-472 ppm). The most influential factor on the compositional content of Sargassum biomass was the season of the year, followed by the extraction method and the place of collection of Sargassum. These results will elucidate information on the biotechnological potential of Sargassum biomass from the Mexican Caribbean, contributing to sustainability challenges of the region, minimizing waste, and making the most of resources.


Assuntos
Sargassum , Biomassa , Região do Caribe , Ecossistema , Estações do Ano
6.
Fish Shellfish Immunol ; 117: 291-298, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34419600

RESUMO

This study investigated the immunomodulatory effects of Sargassum polycystum extract administration in rainbow trout (Oncorhynchus mykiss). S. polycystum methanolic extract was administered orally using feeding needles to individual rainbow trout at the dose of 0 (control), 1 (S1), 3 (S3) and 5 (S5) mg/100 µl/per fish twice a day for 7 days. On 1st, 5th, 3rd and 7th day, blood and tissues were collected from the fish and changes in humoral immune responses and immune-related gene expressions were determined. The result of oxidative radical production showed no difference during early stage of the experiment and was lately decreased (P < 0.05). Lysozyme activity increased on 3rd and 7th day of the study in S5 fish group and on 5th day in S3 group compared to control (P < 0.05). Myeloperoxidase activity had an increased level on the 1st and 3rd day in S1, S5 and S5 fish groups, respectively. IL-1ß gene was significantly up-regulated in kidney and intestine in all experimental groups (except on the 1st day, in the intestine of S5 fish group) compared to control (P < 0.05). IL-8 gene expression was elevated on 1st and 3rd day in kidney of all experimental fish groups. IL-6 transcript enhanced in a dose-dependent manner on 3rd and 7th day. IL-10 and IL-12 genes were also up-regulated. Survival in all treated fish groups challenged with Aeromonas hydrophila was significantly increased compared to that of control. The highest survival rate was recorded in S5 fish group (83.65%) followed by S3 fish group (82.62%). Our results suggest that S. polycystum aqueous methanolic extract is an effective immunostimulant and provide protection against A. hydrophila infection in rainbow trout at a dose of 3-10 mg/20 g body weight/day.


Assuntos
Adjuvantes Imunológicos/farmacologia , Aeromonas hydrophila , Misturas Complexas/farmacologia , Doenças dos Peixes/imunologia , Infecções por Bactérias Gram-Negativas/imunologia , Oncorhynchus mykiss/imunologia , Sargassum , Administração Oral , Animais , Citocinas/genética , Citocinas/imunologia , Doenças dos Peixes/mortalidade , Infecções por Bactérias Gram-Negativas/mortalidade , Infecções por Bactérias Gram-Negativas/veterinária , Muramidase/imunologia , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/microbiologia , Peroxidase/imunologia
7.
Mar Environ Res ; 170: 105453, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34425401

RESUMO

The macro- and microalgae have been found to inhibit the growth and photosynthesis of one another due to allelopathic interactions between them. Sargassum fusiformis is a common and commercially cultivated seaweed in coastal waters of the East China Sea (ECS) and usually encounters dense harmful algal blooms (HABs) formed by dinoflagellates during their sexual reproduction period. In the present study, the effects of Prorocentrum donghaiense lipophilic extracted allelochemicals on the growth and photosynthesis of S. fusiformis zygotes were probed by fast chlorophyll fluorescence rise kinetics and chlorophyll a transient analysis (JIP-test). It was found that exposure to the allelochemicals led to decreased chlorophyll a content and photosynthetic rates of the zygotes in comparison to the ones in the control. In addition, using the JIP-test, it was found that the inhibitory effects of allelochemicals on photosynthesis of the zygotes were mainly exerted on the electron transport within PSII. The decrease of photosynthetic parameters such as VJ, Mo, ϕPo, ϕo, ϕEo, PI, PTR, PET in the zygotes exposed to the allelochemicals all revealed that the obstruction of electron transport, and the dominant decrease in PET, both implied that inhibition on the dark reaction contributed to the highest photosynthetic reduction. In addition, some reaction centers (RCs) in the zygotes exposed to the allelocamicals were inactivated, which led to higher dissipation of excitation energy, as demonstrated by the significant enhancement of the photosynthetic parameter DIo/RC. All the results indicated that the lipophilic extracts contained the allelochemicals of P. donghaiense which could inhibit the growth and photosynthesis of S. fusiformis zygotes by damaging the electron acceptors and inactivating RCs, and finally block the electron transport.


Assuntos
Dinoflagelados , Sargassum , Clorofila , Clorofila A , Fluorescência , Cinética , Feromônios , Fotossíntese , Zigoto
8.
Sci Total Environ ; 795: 148852, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34247081

RESUMO

In the last decade, unprecedented arrivals of pelagic Sargassum (Sargassum influx) have been reported for the Caribbean coasts causing severe ecological and economical affectations and remarking the necessity to characterize the phenomenon. In the north coast of the Mexican Caribbean, spatial characterization of Sargassum influx was performed in terms of its abundance, species composition and chemical content using a combination of in situ sampling and remote sensing evaluations. Sargassum influx was detected within the 25 km fringe near to Quintana Roo coast in coincidence with beach-cast events during September 2018. Significant spatial variation in abundance and species composition of the stranded biomass was found for the six localities studied, which was related to the local environmental conditions. Pelagic species of Sargassum were the main component ranging from 78.1 to 99.6% of the total beach-cast (wrack) fresh biomass, whereas benthic macrophytes (seagrasses and macroalgae) were a minor component reaching up to 21% in some localities. The biochemical composition of beach-cast Sargassum resulted spatially homogeneous for most of the components analyzed; only carbon tissue content, ash metals (particularly Fe and As) and isotopic composition changed spatially. This study represents baseline information for the region. Long-term seasonal evaluations of Sargassum influx along Mexican Caribbean are required to define adequate management strategies and exploitation.


Assuntos
Sargassum , Alga Marinha , Biomassa , Região do Caribe , Índias Ocidentais
9.
Mar Pollut Bull ; 170: 112673, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34225191

RESUMO

In this study, we aim to explore the allelochemicals of marine brown algae Sargassum fusiforme and the mechanism of allelopathy effect on Heterosigma akashiwo. Six potential allelopathic substances, palmitic acid, arachidonic acid, α-linolenic acid (ALA), fucosterol, 24-hydroperoxy-24-vinylcholesterol, and saringosterowere, were isolated and identified from S. fusiforme by column chromatography, NMR, TOF-MS and GC-MS analyses. The ALA and 24-hydroperoxy-24-vinylcholesterol showed remarkable inhibitory activities on H. akashiwo growth. Besides, the allelopathic mechanism between the ALA and H. akashiwo was preliminarily investigated. The results indicated that the activities of SOD and POD of H. akashiwo gradually decreased under high ALA concentration. The reduction of photosynthetic pigments and chlorophyll fluorescence parameters, as well as apparent electron transport rate in H. akashiwo cells, aggravated gradually with increasing the concentration of the ALA. In summary, this study revealed the responses of morphology and physiology of H. akashiwo when exposed by ALA, while revealing the potential of macroalgae in red tide control.


Assuntos
Microalgas , Sargassum , Alelopatia , Proliferação Nociva de Algas , Feromônios
10.
Ultrason Sonochem ; 77: 105671, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34304119

RESUMO

The development of green and sustainable extraction technologies for various naturally active biomaterials is gaining increasing attention due to their environmentally friendly advantages. In this work, the ultrasonic-assisted extraction of fucoxanthin from edible brown algae Sargassum fusiforme using different green solvents was presented. Ethyl lactate, limonene, soybean oil, and sunflower oil were used in place of traditional organic solvents. Ethyl lactate showed similar performance to organic solvents, whereas limonene and vegetable oil exhibited higher selectivity for fucoxanthin. Moreover, the effects of various extraction factors, including liquid/solid ratio, extraction time, extraction temperature, as well as amplitude were studied. The optimal conditions were optimized as follows: liquid/solid ratio, 40 mL/g; extraction time, 27 min; extraction temperature, 75 ℃; amplitude, 53%; and solvent, ethyl lactate. Optimal model of second-order kinetic parameters (rate constant, equilibrium concentration, and initial extraction rate) was successfully developed for describing the dynamic ultrasonic extraction process under different operating conditions.


Assuntos
Modelos Químicos , Sargassum/química , Solventes/química , Ondas Ultrassônicas , Xantofilas/isolamento & purificação , Química Verde , Cinética
11.
Molecules ; 26(13)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206231

RESUMO

As an abundant marine xanthophyll, fucoxanthin (FX) exhibits a broad range of biological activities. The preparation of high-purity FX is in great demand, however, most of the available methods require organic solvents which cannot meet the green chemistry standard. In the present study, a simple and efficient purification approach for the purification of FX from the brown seaweed Sargassum horneri was carried out. The FX-rich ethanol extract was isolated by octadecylsilyl (ODS) column chromatography using ethanol-water solvent as a gradient eluent. The overwhelming majority of FX was successfully eluted by the ethanol-water mixture (9:1, v/v), with a recovery rate of 95.36%. A parametric study was performed to optimize the aqueous ethanol precipitation process by investigating the effects on the purity and recovery of FX. Under the optimal conditions, the purity of FX was 91.07%, and the recovery rate was 74.98%. Collectively, the eco-friendly method was cost-efficient for the purification of FX. The developed method provides a potential approach for the large-scale production of fucoxanthin from the brown seaweed Sargassum horneri.


Assuntos
Etanol/química , Sargassum/química , Xantofilas/química , Xantofilas/isolamento & purificação , Cromatografia
12.
Zootaxa ; 4970(1): 119130, 2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-34186906

RESUMO

A new marine Sargassum-boring species of Limnoria (Limnoriidae) is described on the basis of specimens obtained at Kamogawa-shi, Chiba Prefecture, Japan. Limnoria aspera sp. nov. shares a reduced mandibular palp to a seta, algal-feeding, and the clavate shaped epipod of the maxilliped with the other species of non-mandibular-palp group. L. aspera sp. nov. differs morphologically from the congeneric species by secondary unguis of pereopods and unique carinae of pleonite 5 and pleotelson. We describe the sequences of the mitochondrial COI gene and the nuclear 28S rDNA gene. L. aspera sp. nov. differs by 14.218.0% in p-distance based on COI sequences from other Japanese species, L. furca and L. nagatai.


Assuntos
Isópodes/anatomia & histologia , Isópodes/classificação , Sargassum , Animais , DNA Ribossômico/genética , Genes Mitocondriais , Japão
13.
Molecules ; 26(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071584

RESUMO

Avian leukosis virus subgroup J (ALV-J) is an immunosuppressive virus which has caused heavy losses to the poultry breeding industry. Currently, there is no effective medicine to treat this virus. In our previous experiments, the low-molecular-weight Sargassum fusiforme polysaccharide (SFP) was proven to possess antiviral activity against ALV-J, but its function was limited to the virus adsorption stage. In order to improve the antiviral activity of the SFP, in this study, three new SFP long-chain alkyl group nanomicelles (SFP-C12M, SFP-C14M and SFP-C16M) were prepared. The nanomicelles were characterized according to their physical and chemical properties. The nanomicelles were characterized by particle size, zeta potential, polydispersity index, critical micelle concentration and morphology. The results showed the particle sizes of the three nanomicelles were all approximately 200 nm and SFP-C14M and SFP-C16M were more stable than SFP-C12M. The newly prepared nanomicelles exhibited a better anti-ALV-J activity than the SFP, with SFP-C16M exhibiting the best antiviral effects in both the virus adsorption stage and the replication stage. The results of the giant unilamellar vesicle exposure experiment demonstrated that the new virucidal effect of the nanomicelles might be caused by damage to the phospholipid membrane of ALV-J. This study provides a potential idea for ALV-J prevention and development of other antiviral drugs.


Assuntos
Antivirais/química , Antivirais/farmacologia , Micelas , Nanopartículas/química , Polissacarídeos/química , Doenças das Aves Domésticas/prevenção & controle , Sargassum/metabolismo , Adsorção , Animais , Vírus da Leucose Aviária/efeitos dos fármacos , Química Farmacêutica/métodos , Galinhas , Carboidratos da Dieta/farmacologia , Regulação da Expressão Gênica , Interações Hidrofóbicas e Hidrofílicas , Concentração Inibidora 50 , Luz , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Nanotecnologia , Tamanho da Partícula , Aves Domésticas , Espalhamento de Radiação , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Nutrients ; 13(6)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34064139

RESUMO

The therapeutic potential of Sargassum siliquosum grown in Australian tropical waters was tested in a rat model of metabolic syndrome. Forty-eight male Wistar rats were divided into four groups of 12 rats and each group was fed a different diet for 16 weeks: corn starch diet (C); high-carbohydrate, high-fat diet (H) containing fructose, sucrose, saturated and trans fats; and C or H diets with 5% S. siliquosum mixed into the food from weeks 9 to 16 (CS and HS). Obesity, hypertension, dyslipidaemia, impaired glucose tolerance, fatty liver and left ventricular fibrosis developed in H rats. In HS rats, S. siliquosum decreased body weight (H, 547 ± 14; HS, 490 ± 16 g), fat mass (H, 248 ± 27; HS, 193 ± 19 g), abdominal fat deposition and liver fat vacuole size but did not reverse cardiovascular and liver effects. H rats showed marked changes in gut microbiota compared to C rats, while S. siliquosum supplementation increased gut microbiota belonging to the family Muribaculaceae. This selective increase in gut microbiota likely complements the prebiotic actions of the alginates. Thus, S. siliquosum may be a useful dietary additive to decrease abdominal and liver fat deposition.


Assuntos
Suplementos Nutricionais , Síndrome Metabólica/terapia , Obesidade/terapia , Sargassum , Alga Marinha/microbiologia , Gordura Abdominal/microbiologia , Animais , Peso Corporal/fisiologia , Dieta/efeitos adversos , Modelos Animais de Doenças , Microbioma Gastrointestinal/fisiologia , Fígado/microbiologia , Masculino , Síndrome Metabólica/etiologia , Síndrome Metabólica/microbiologia , Obesidade/etiologia , Obesidade/microbiologia , Prebióticos/microbiologia , Ratos , Ratos Wistar
15.
Food Chem Toxicol ; 153: 112246, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33940104

RESUMO

There are few studies on seaweed polysaccharides with UV/H2O2 treatment, so the aim of this study was to evaluate the effects of UV/H2O2 treatment on physicochemical properties and RAW 264.7 cells responses of polysaccharides from Sargassum fusiforme (PSF). Results showed that the contents of reducing sugar and sulfate in PSF with UV/H2O2 treatment for 2 h increased by 202.86% and 31.77%, respectively, and the contents of total sugar, protein and uronic acid decreased by 14.29%, 57.11% and 43.18% compared with those of original polysaccharides. In addition, UV/H2O2 treatment did not change the monosaccharide types of original polysaccharides, but it could change its monosaccharide composition and surface morphology. Besides, polysaccharides after UV/H2O2 treatment for 0.5-2 h had lower toxicity than original polysaccharides in RAW 264.7 cells. Typically, PSF with UV/H2O2 treatment for 2 h (PSF-T2) could effectively inhibit pro-inflammatory molecules production (including NO, IL-1ß, IL-6 and TNF-α), and down-regulate related genes expression (including Tlr4, Irak, Il-1ß, Il-6, Il-12 and Tnf-α). Therefore, UV/H2O2 treatment is a potential way to prepare polysaccharide with better anti-inflammatory activity.


Assuntos
Peróxido de Hidrogênio , Macrófagos/efeitos dos fármacos , Polissacarídeos/metabolismo , Sargassum/efeitos dos fármacos , Sargassum/efeitos da radiação , Raios Ultravioleta , Animais , Citocinas/genética , Citocinas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamação/induzido quimicamente , Lipopolissacarídeos/toxicidade , Camundongos , Polissacarídeos/farmacologia , Células RAW 264.7 , Sargassum/metabolismo , Receptor 4 Toll-Like
16.
Nat Commun ; 12(1): 2556, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33963184

RESUMO

Ensuring that global warming remains <2 °C requires rapid CO2 emissions reduction. Additionally, 100-900 gigatons CO2 must be removed from the atmosphere by 2100 using a portfolio of CO2 removal (CDR) methods. Ocean afforestation, CDR through basin-scale seaweed farming in the open ocean, is seen as a key component of the marine portfolio. Here, we analyse the CDR potential of recent re-occurring trans-basin belts of the floating seaweed Sargassum in the (sub)tropical North Atlantic as a natural analogue for ocean afforestation. We show that two biogeochemical feedbacks, nutrient reallocation and calcification by encrusting marine life, reduce the CDR efficacy of Sargassum by 20-100%. Atmospheric CO2 influx into the surface seawater, after CO2-fixation by Sargassum, takes 2.5-18 times longer than the CO2-deficient seawater remains in contact with the atmosphere, potentially hindering CDR verification. Furthermore, we estimate that increased ocean albedo, due to floating Sargassum, could influence climate radiative forcing more than Sargassum-CDR. Our analysis shows that multifaceted Earth-system feedbacks determine the efficacy of ocean afforestation.


Assuntos
Atmosfera/análise , Dióxido de Carbono/análise , Aquecimento Global/prevenção & controle , Sargassum/isolamento & purificação , Oceano Atlântico , Biomassa , Cálcio/análise , Ecossistema , Retroalimentação , Concentração de Íons de Hidrogênio , Água do Mar/análise , Água do Mar/química , Temperatura , Fatores de Tempo , Clima Tropical
17.
Harmful Algae ; 103: 102001, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33980441

RESUMO

Blooms of floating macroalgae have been reported around the world, among which are recurrent blooms of Ulva prolifera and Sargassum horneri in the Yellow Sea and East China Sea. While satellite remote sensing has often been used to estimate their distributions and abundance as well as to trace their origins, because the algae mats are often much smaller than the size of an image pixel, it is unclear to what extent they can be detected and discriminated from each other in satellite imagery. Using data collected from laboratory experiments and by the Sentinel-3 OLCI (Ocean and Land Colour Instrument) and Sentinel-2 MSI (Multi Spectral Instrument) satellite instruments, we conduct simulated experiments to determine the lower detection limit and discrimination limit for these two macroalgae in different water environments and under different atmospheric conditions. For OLCI, the detection limit for both macroalgae is about 0.5% of a pixel, while the discrimination limit varies between 0.8% for clear water and 2% for turbid water. For MSI, the detection limit is about 2%, while the discrimination limit is about 6% for all water types. Below these two limits, detection and discrimination of macroalgae in these regions using the two sensors are subject to large uncertainties, thus requiring additional caution when interpreting algae areas and tracing algae origins.


Assuntos
Sargassum , Ulva , China , Eutrofização , Imagens de Satélites
18.
Food Chem ; 358: 129908, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933948

RESUMO

A fucoidan SFP, having novel structure, was extracted from Sargassum fusiforme. It had a molecular weight of 703 kDa and was composed of fucose and galactose with the ratio of 73.16:26.84 (mol%). Structural analyses showed that it mainly consisted of 1,3-, 1,4-, 1,3,4-linked-α-l-Fucp and 1,3-, 1,6-linked-ß-d-Galp, with partial sulfation at C-4, C-3 of fucose units and C-6, C-3 of galactose units. The branches consisted of sulfated fucosyl and galactofucosyl oligosaccharides. The regulatory effects of SFP on the intestinal microbiota in high-fat diet-fed mice were investigated. The high-dosage SFP exhibited good hypolipidemic effects, especially in regulating the high-densitylipoproteincholesterol, non-esterified fatty acid levels and lipase activity. It also significantly decreased the ratio of phyla Firmicutes/Bacteroidetes (P < 0.05). Besides, SFP had certain effects on the richness and diversity of intestinal microbiota. Therefore, SFP exhibited novel structure and certain beneficial effects on the disorder of intestinal microbiota in high-fat diet-fed mice.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Microbioma Gastrointestinal/efeitos dos fármacos , Polissacarídeos/química , Polissacarídeos/farmacologia , Sargassum/química , Animais , Sequência de Carboidratos , Fucose/química , Galactose/química , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiologia , Hipolipemiantes/química , Hipolipemiantes/farmacologia , Masculino , Camundongos , Peso Molecular , Sulfatos/química
19.
Int J Biol Macromol ; 183: 589-599, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33933545

RESUMO

Consumption of marine alga-based polysaccharides as additional functional foods can endow with health benefits by diminishing the risk of chronic diseases. A polygalacto-fucopyranose characterized as [→1)-2, 4-SO3-α-Fucp-(3 → 1)-{2-SO3-α-Fucp-(3→}] with [(4 → 1)-6-OAc-ß-Galp-(4→] side chain isolated from marine alga Sargassum wightii exhibited potential antihypertensive activity. Upon treatment with studied polygalactofucan (50 mg/kg BW), serum hypertension biomarkers troponin-T (1.3 pg/mL), troponin-I (1.2 µg/dL) and angiotensin-II converting enzyme (0.18 pg/mL) were significantly recovered in hypertensive rats compared to disease control. Serum cardiovascular risk indices of diseased rats were significantly decreased (< 10%, p < 0.05) after administration of the studied galactofucan (50 mg/kg BW) related to hypertension group (> 17%), and were comparable with standard antihypertensive agent telmisartan (8.3-10.2% at 2 mg/kg BW). The studied compound was safe for consumption as obvious from the high LD50 value (>5 g/kg), and could be developed as a prospective functional food ingredient attenuating the pathophysiological attributes causing hypertension-related conditions.


Assuntos
Anti-Hipertensivos/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Fucose/farmacologia , Hipertensão/tratamento farmacológico , Sargassum , Animais , Anti-Hipertensivos/isolamento & purificação , Anti-Hipertensivos/toxicidade , Cloreto de Cádmio , Modelos Animais de Doenças , Descoberta de Drogas , Fucose/análogos & derivados , Fucose/isolamento & purificação , Fucose/toxicidade , Hipertensão/induzido quimicamente , Hipertensão/fisiopatologia , Dose Letal Mediana , Masculino , Ratos Wistar , Sargassum/química , Telmisartan/farmacologia
20.
Int J Biol Macromol ; 183: 1427-1435, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34023368

RESUMO

The aim of this study was to establish the fine structure of fucoidan from Sargassum oligocystum and to study the radiosensitizing effect of fucoidans from three algae of genus Sargassum (S. oligocystum, S. duplicatum, and S. feldmannii) with different structures. The fucoidan SoF2 from S. oligocystum was sulfated (32%) galactofucan (Fuc:Gal = 2:1), with a Mw of 183 kDa (Mw/Mn = 2.0). Its supposed structure was found to be predominantly 1,3-linked fucose as the main chain, with branching points at C2 and C4. The branches could be single galactose and/or fucose short chains with terminal galactose residues. Sulfate groups were found at positions C3, C2, and/or C4 of fucose residues and at C2 and/or C4 of galactose residues. The radiosensitizing effect of galactofucans from S. oligocystum, S. duplicatum, and S. feldmannii against human melanoma SK-MEL-28, colon HT-29, and breast MDA-MB-231 cancer cells was investigated. The influence of all investigated polysaccharides treatments with/without X-ray radiation on colony formation of human melanoma cells SK-MEL-28 was weak. Fucoidan from S. feldmannii has been shown to be the most promising radiosensitizing compound against human colon HT-29 and breast MDA-MB-231 cancer cells.


Assuntos
Polissacarídeos/química , Sargassum/química , Linhagem Celular Tumoral , Células HT29 , Humanos , Radiossensibilizantes/química
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