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1.
Chem Commun (Camb) ; 55(79): 11948-11951, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31531452

RESUMO

The toxic halogenated anilines 2,4,6-tribromoaniline, 2,4,6-trichloroaniline and their dibromochloro and bromodichloro derivatives were considered as compounds of exclusive synthetic origin. Labeling studies and kinetic experiments confirmed that these substances are also biosynthesized by a marine biofilm forming microalga. They represent a novel class of halogenated natural products.


Assuntos
Compostos de Anilina/química , Biofilmes , Produtos Biológicos/química , Halogênios/química , Microalgas/química , Vias Biossintéticas , Halogenação , Cinética
2.
Bioresour Technol ; 291: 121819, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31369925

RESUMO

In this study, experiments on pretreating one species of microalgae (Chlorella pyrenoidosa) using one kind of ionic liquid (IL) of [BMIM]Cl were conducted. The aim of this work is to evaluate the recycling efficacy of expensive IL solvent for effective cell disruption. It was indicated that the molecular structure of IL was stable during the recycling test. Five times antisolvent precipitation of microalgae debris after lipid extraction using methanol recovered 99.8% IL with the energy consumption of 4.46 MJ per kg dry Chlorella pyrenoidosa. The chromatography was used to separate IL and hydrolysates, resulting in the IL loss below 1.97 g per kg dry Chlorella pyrenoidosa.


Assuntos
Chlorella/química , Imidazóis/química , Lipídeos/isolamento & purificação , Microalgas/química , Esgotos
3.
Food Chem ; 301: 125286, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31382110

RESUMO

Nervonic acid (NA) has attracted considerable attention because of its close relationship with brain development. Sources of NA include oil crop seeds, oil-producing microalgae, and other microorganisms. Transgenic technology has also been applied to improve the sources and production of NA. NA can be separated and purified by urea adduction fractionation, molecular distillation, and crystallization. Studies on NA functionality involved treatments for demyelinating diseases and acquired immunodeficiency syndrome, as well as prediction of mortality due to cardiovascular diseases and chronic kidney disease. This mini review focuses on the sources, production, and biological functions of NA and provides prospective trends in the investigation of NA.


Assuntos
Ácidos Graxos Monoinsaturados/isolamento & purificação , Ácidos Graxos Monoinsaturados/metabolismo , Microalgas/química , Óleos Vegetais/química
4.
J Agric Food Chem ; 67(34): 9569-9578, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31385495

RESUMO

Acetyl-CoA synthetase (ACS) plays a key role in microalgal lipid biosynthesis and acetyl-CoA industrial production. In the present study, two ACSs were cloned and characterized from the oleaginous microalga Chromochloris zofingiensis. In vitro kinetic analysis showed that the Km values of CzACS1 and CzACS2 for potassium acetate were 0.99 and 0.81 mM, respectively. Moreover, CzACS1 and CzACS2 had outstanding catalytic efficiencies (kcat/Km), which were 70.67 and 79.98 s-1 mM-1, respectively, and these values were higher than that of other reported ACSs. CzACS1 and CzACS2 exhibited differential expression patterns at the transcriptional level under various conditions. Screening a recombinant library of 52 transcription factors (TFs) constructed in the present study via yeast one-hybrid assay pointed to seven TFs with potential involvement in the regulation of the two ACS genes. Expression correlation analysis implied that GATA20 was likely an important regulator of CzACS2 and that ERF9 could regulate two CzACSs simultaneously.


Assuntos
Acetato-CoA Ligase/metabolismo , Clorófitas/enzimologia , Regulação Enzimológica da Expressão Gênica , Microalgas/enzimologia , Acetato-CoA Ligase/química , Acetato-CoA Ligase/genética , Biocatálise , Clorófitas/química , Clorófitas/genética , Cinética , Metabolismo dos Lipídeos , Microalgas/química , Microalgas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
5.
J Agric Food Chem ; 67(34): 9667-9682, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31415166

RESUMO

This study assessed the feasibility of an NMR metabolomics approach coupled to multivariate data analysis to monitor the naturally present or stresses-elicited metabolites from a long-term (>170 days) culture of the dinoflagellate marine microalgae Amphidinium carterae grown in a fiberglass paddlewheel-driven raceway photobioreactor. Metabolic contents, in particular, in two members of the amphidinol family, amphidinol A and its 7-sulfate derivative amphidinol B (referred as APDs), and other compounds of interest (fatty acids, carotenoids, oxylipins, etc.) were evaluated by altering concentration levels of the f/2 medium nutrients and daily mean irradiance. Operating with a 24 h sinusoidal light cycle allowed a 3-fold increase in APD production, which was also detected by an increase in hemolytic activity of the methanolic extract of A. carterae biomass. The presence of APDs was consistent with the antitumoral activity measured in the methanolic extracts of the biomass. Increased daily irradiance was accompanied by a general decrease in pigments and an increase in SFAs (saturated fatty acids), MUFAs (monounsaturated fatty acids), and DHA (docosahexaenoic acid), while increased nutrient availability lead to an increase in sugar, amino acid, and PUFA ω-3 contents and pigments and a decrease in SFAs and MUFAs. NMR-based metabolomics is shown to be a fast and suitable method to accompany the production of APD and bioactive compounds without the need of tedious isolation methods and bioassays. The two APD compounds were chemically identified by spectroscopic NMR and spectrometric ESI-IT MS (electrospray ionization ion trap mass spectrometry) and ESI-TOF MS (ESI time-of-flight mass spectrometry) methods.


Assuntos
Dinoflagelados/metabolismo , Macrolídeos/química , Espectroscopia de Ressonância Magnética/métodos , Metabolômica/métodos , Microalgas/metabolismo , Carotenoides/química , Carotenoides/metabolismo , Dinoflagelados/química , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Macrolídeos/metabolismo , Microalgas/química , Análise Multivariada
6.
J Photochem Photobiol B ; 197: 111551, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31306954

RESUMO

Heavy metal pollution as one of the most serious pollution problems of marine environment, seriously threatens the safety of marine organism and human health, and will lead to potential risks for the marine ecological environment. In order to develop a rapid and sensitive toxicity detection method for marine heavy metals, in this study, marine diatom Nitzschia closterium was used as the test organism, and the effects of different concentrations of lead (Pb) on the five chlorophyll fluorescence parameters of N. closterium including the maximum photochemical quantum yield of PSII (Fv/Fm), the effective quantum yield of PSII photochemical energy conversion (ΦPSII), the effective absorption cross section of PSII photochemistry (σPSII'), the relative electron transfer rate of PSII (rP), and the PSII electron flux per unit volume (JVPII) at different exposure times were investigated based on chlorophyll fluorescence technology. By comparing with the photosynthetic activity fluorescence parameter Fv/Fm which is commonly used for toxicity analysis of pollutants using algae as test organisms, the optimal chlorophyll fluorescence parameter that could rapidly and sensitively determine Pb toxicity to N. closterium was selected. The results indicate that all the five chlorophyll fluorescence parameters of Fv/Fm, ΦPSII, σPSII', rP and JVPII showed good dose-response relationships with Pb within 8 h exposure time, and they all could be used as endpoints to rapidly determine Pb toxicity to N. closterium. Among the five chlorophyll fluorescence parameters, JVPII was the most sensitive fluorescence parameter for detecting the toxicity of Pb to N. closterium within 6 h exposure. And for JVPII, the median effective concentration (EC50) values of Pb at 2, 4 and 6 h were 0.329, 0.068 and 0.040 mmol L-1, respectively. However, when the exposure time was 8 h, ΦPSII was the most sensitive fluorescence parameter for the toxicity detection of Pb, and the EC50 value of Pb at 8 h was 0.038 mmol L-1. This study will provide an important basis for the development of a rapid and sensitive detection method for the biological toxicity of marine heavy metals, and those results will be helpful for ecological risk assessment in marine environment.


Assuntos
Clorofila/química , Chumbo/toxicidade , Microalgas/efeitos dos fármacos , Microalgas/química , Microalgas/metabolismo , Complexo de Proteína do Fotossistema II/química , Complexo de Proteína do Fotossistema II/metabolismo , Teoria Quântica , Espectrometria de Fluorescência , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade
7.
Carbohydr Polym ; 222: 114962, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31320077

RESUMO

The relevance of microalgae biotechnology for producing high-value compounds with biomedical application, such as polysaccharides, has been increasing. Despite this, the knowledge about the composition and structure of microalgae polysaccharides is still scarce. In this work, water-soluble polysaccharides from Nannochloropsis oculata were extracted, fractionated, structurally analysed, and subsequently tested in terms of immunostimulatory activity. A combination of sugar and methylation analysis with interaction data of carbohydrate-binding proteins using carbohydrate microarrays disclosed the complex structural features of the different polysaccharides. These analyses showed that the water-soluble polysaccharides fractions from N. oculata were rich in (ß1→3, ß1→4)-glucans, (α1→3)-, (α1→4)-mannans, and anionic sulphated heterorhamnans. The immunostimulatory assay highlighted that these fractions could also stimulate murine B-lymphocytes. Thus, the N. oculata water-soluble polysaccharides show potential to be further explored for immune-mediated biomedical applications.


Assuntos
Linfócitos B/efeitos dos fármacos , Microalgas/química , Polissacarídeos/imunologia , Estramenópilas/química , Animais , Desoxiaçúcares/análise , Glucanos/análise , Imunização , Mananas/análise , Camundongos , Camundongos Endogâmicos BALB C , Polissacarídeos/química , Polissacarídeos/farmacologia
8.
Environ Pollut ; 252(Pt B): 1582-1592, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279252

RESUMO

Localised sites in Antarctica are contaminated with mixtures of metals, yet the risk this contamination poses to the marine ecosystem is not well characterised. Recent research showed that two Antarctic marine microalgae have antagonistic responses to a mixture of five common metals (Koppel et al., 2018a). However, the metal accumulating potential and risk to secondary consumers through dietary exposure are still unknown. This study investigates cellular accumulation following exposure to a mixture of cadmium, copper, nickel, lead, and zinc for the Antarctic marine microalgae, Phaeocystis antarctica and Cryothecomonas armigera. In both microalgae, cellular cadmium, copper, and lead concentrations increased with increasing exposures while cellular nickel and zinc did not. For both microalgae, copper in the metal mixture drives inhibition of growth rate with R2 values > -0.84 for all cellular fractions in both species and the observed antagonism was likely caused by zinc competition, having significantly positive partial regressions. Metal accumulation to P. antarctica and C. armigera is likely to be toxic to consumer organisms, with low exposure concentrations resulting in cellular concentrations of 500 and 1400 × 10-18 mol Zn cell-1 and 160 and 320 × 10-18 mol Cu cell-1, respectively.


Assuntos
Haptófitas/química , Metais Pesados/análise , Microalgas/química , Poluentes Químicos da Água/análise , Animais , Regiões Antárticas , Exposição Dietética/análise , Cadeia Alimentar , Haptófitas/crescimento & desenvolvimento , Metais Pesados/toxicidade , Microalgas/crescimento & desenvolvimento , Modelos Teóricos , Risco , Poluentes Químicos da Água/toxicidade
9.
Mar Pollut Bull ; 144: 189-195, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31179987

RESUMO

Populations of Acropora palmata and Orbicella faveolata, two important reef-building corals, have declined precipitously across the Caribbean region since at least the 1970s. Recruitment failure may be limiting population recovery, possibly due to lack of suitable settlement habitat. Here, we examine the effects of algal turfs and algal turfs + sediment, two widely abundant substrate types across the Florida Keys, on the settlement of these two ecologically-important species. We show that sediment significantly impedes coral settlement, reducing settlement 10- and 13-fold for A. palmata and O. faveolata, respectively, compared to turf algae alone. This result is corroborated by our field survey data that showed a strong, negative relationship between the abundance of turf + sediment and the abundance of juvenile corals. Turf algae alone did not reduce coral settlement. Our results suggest that sediment-laden turf algae are detrimental to settling corals, but that turf algae alone may be relatively benign.


Assuntos
Antozoários/crescimento & desenvolvimento , Recifes de Corais , Espécies em Perigo de Extinção , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Microalgas/química , Animais , Região do Caribe , Ecologia , Ecossistema , Florida
10.
Mar Drugs ; 17(6)2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31159386

RESUMO

The utilization of microalgae as a source of carotenoid productions has gained increasing popularity due to its advantages, such as a relatively fast turnaround time. In this study, a newly discovered Coelastrum sp. TISTR 9501RE was characterized and investigated for its taxonomical identity and carotenoid profile. To the best of our knowledge, this report was the first to fully investigate the carotenoid profiles in a microalga of the genus Coelastrum. Upon use of limited nutrients as a stress condition, the strain was able to produce astaxanthin, canthaxanthin, and lutein, as the major carotenoid components. Additionally, the carotenoid esters were found to be all astaxanthin derivatives, and ß-carotene was not significantly present under this stress condition. Importantly, we also demonstrated that this practical stress condition could be combined with simple growing factors, such as ambient sunlight and temperature, to achieve even more focused carotenoid profiles, i.e., increased overall amounts of the aforementioned carotenoids with fewer minor components and chlorophylls. In addition, this green microalga was capable of tolerating a wide range of salinity. Therefore, this study paved the way for more investigations and developments on this fascinating strain, which will be reported in due course.


Assuntos
Antioxidantes/metabolismo , Carotenoides/química , Carotenoides/metabolismo , Descoberta de Drogas/métodos , Microalgas/química , Microalgas/fisiologia , Estresse Fisiológico/fisiologia , Luz Solar , Temperatura Ambiente
11.
Bioresour Technol ; 289: 121694, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31254897

RESUMO

The Nordic microalgal strain Haematococcus pluvialis was exposed to various stress conditions to induce astaxanthin accumulation. Highest carotenoid content (19.1 mg·g-1dw) was achieved in nitrogen-free culture medium at a high light intensity. The efficiency of Pulsed Electric Field (PEF) pre-treatment of stressed fresh biomass of H. pluvialis followed by incubation in the growth medium was compared to classical disruption methods (bead-beating, freezing-thawing, thermal treatment or ultrasound) for the subsequent extraction of astaxanthin in ethanol. N-starved cells treated with PEF followed by aqueous incubation for 6 h resulted in extraction of 96% (18.3 mgcar·gdw-1) of the total carotenoid content compared to 80% (15.3 mgcar·gdw-1) using other physical methods. The proportion of free forms of astaxanthin was higher in PEF-treated samples compared to mechanical disruption, suggesting PEF triggering an esterase activity. PEF pre-treatment of the cells followed by incubation in growth medium improved astaxanthin extraction in the eco-friendly solvent ethanol.


Assuntos
Clorofíceas/química , Microalgas/química , Biomassa , Eletricidade , Xantofilas/isolamento & purificação
12.
J Sci Food Agric ; 99(13): 6066-6075, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31228262

RESUMO

BACKGROUND: Isochrysis sp. is a marine microalga, rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The potential use of its biomass as an alternative source of polyunsaturated fatty acids (PUFAs) has not been studied in animal models. Male albino Wistar rats were divided into three groups and treated for 28 days. The rats were fed with (1) standard chow (control group), (2) microalgal biomass rich in EPA and DHA along with standard chow (microalga group), and (3) fish oil that contains equivalent amounts of EPA and DHA along with standard chow (fish oil group). After intervention, biochemical indices, histopathological indices, relative mRNA expression of PUFA genes, antioxidant genes, inflammatory markers, and the fatty acid profile of major tissues were studied. RESULTS: Animals treated with microalgal biomass showed significantly increased serum HDL levels (P < 0.05) and reduced oxidative stress markers with a concomitant decrease in urea and creatinine levels. Oral supplementation of microalgal biomass did not show any toxicity or damage in any major organs. The mRNA expression of PUFA genes was significantly downregulated (P < 0.05) and antioxidant genes were upregulated. Furthermore, the mRNA expression of pro-inflammatory markers was significantly downregulated (P < 0.05) and anti-inflammatory markers were upregulated. Oral supplementation of microalgal biomass improved DHA status in brain and liver. CONCLUSION: The present study demonstrated that Isochrysis sp. can be used as a safe, alternative food supplement for ω-3 fatty acids. © 2019 Society of Chemical Industry.


Assuntos
Antioxidantes/metabolismo , Suplementos Nutricionais/análise , Ácidos Docosa-Hexaenoicos/metabolismo , Ácido Eicosapentaenoico/análogos & derivados , Haptófitas/química , Lipídeos/sangue , Microalgas/química , Animais , Encéfalo/metabolismo , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/metabolismo , Ácidos Graxos Insaturados/metabolismo , Expressão Gênica , Haptófitas/crescimento & desenvolvimento , Haptófitas/metabolismo , Fígado/metabolismo , Masculino , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Ratos , Ratos Wistar
13.
Food Chem Toxicol ; 131: 110558, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31175915

RESUMO

Effects of Spirulina platensis 55% ethanol extract (SPL55) on lipid metabolism in high-fat diet-induced hyperlipidaemic rats were investigated. Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry indicated that SPL55 was enriched with polyunsaturated fatty acids. Meanwhile, serum and liver lipid levels, including total triglyceride, total cholesterol, and low-density-lipoprotein cholesterol, were significantly decreased in hyperlipidaemic rats of SPL55. Analysis of tissue sections showed that SPL55 treatment could markedly inhibit hepatic lipid accumulation and steatosis. Moreover, SPL55 regulated the mRNA and protein expression levels of SREBP-1c, HMG-CoA, PEPCK, ACC, and AMPK genes involved in lipid metabolism. Furthermore, SPL55 led to decrease the abundances of Turicibacter, Clostridium_XlVa, and Romboutsia, which were positive correlation with lipid metabolism indicators, and has also enriched Alloprevotella, Prevotella, Porphyromonadaceae, and Barnesiella. These results provided evidence that SPL55 might be developed as a functional food to ameliorate lipid metabolic disorders and hyperlipidaemia.


Assuntos
Ácidos Graxos Insaturados/farmacologia , Fígado Gorduroso/prevenção & controle , Microbioma Gastrointestinal/efeitos dos fármacos , Spirulina/química , Animais , Peso Corporal/efeitos dos fármacos , HDL-Colesterol/sangue , HDL-Colesterol/metabolismo , LDL-Colesterol/sangue , LDL-Colesterol/metabolismo , Dieta Hiperlipídica , Ácidos Graxos Insaturados/metabolismo , Expressão Gênica/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Fígado/patologia , Microalgas/química , Ratos , Ratos Wistar , Triglicerídeos/sangue , Triglicerídeos/metabolismo
14.
Microb Cell Fact ; 18(1): 113, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253148

RESUMO

BACKGROUND: Microalgae have been proposed as potential platform to produce lipid-derived products, such as biofuels. Knowledge on the intracellular carbon flow distribution may identify key metabolic processes during lipid synthesis thus refining culture/genetic strategies to maximize cell lipid productivity. A kinetic metabolic model simulating cell metabolic behavior and lipid production was first applied in the microalgae platform Chlorella protothecoides under heterotrophic condition. It combines both physiology and flux information in a kinetic approach. Cell nutrition, growth, lipid production and almost 30 metabolic intermediates covering central carbon metabolism were included and simulated. RESULTS: Model simulations were shown to adequately agree with experimental data, which is suggesting that the proposed model copes with Chlorella protothecoides cells' biology. The dynamic metabolic flux analysis using the model showed a reversible starch flux from accumulation to decomposing when glucose reached depletion, while net lipid flux shows a quasi-constant rate. The sensitive flux parameters on starch and lipid metabolism suggested that starch synthesis is the major competing pathway that affects lipid accumulation in C. protothecoides. Flux analysis also demonstrated that high lipid yield under heterotrophic condition is accompanied with high lipid flux and low TCA activity. Meanwhile, the dynamic flux distribution also suggests a relatively constant ratio of glucose distributed to biomass, lipid, starch, nucleotides as well as pentose phosphate pathway. CONCLUSION: The model described not only experimental data, but also unraveled intracellular carbon flow distribution and identify key metabolic processes during lipid synthesis. Most of the metabolic kinetics also showed statistical significance for metabolic mechanism. Therefore, this study unravels the mechanisms of the glucose impact on the dynamic carbon flux distribution, thus improving our understanding of the links between carbon fluxes and lipid metabolism in C. protothecoides.


Assuntos
Chlorella/metabolismo , Lipídeos/biossíntese , Lipídeos/química , Carbono/metabolismo , Chlorella/química , Chlorella/crescimento & desenvolvimento , Glucose/metabolismo , Processos Heterotróficos , Cinética , Análise do Fluxo Metabólico , Microalgas/química , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Via de Pentose Fosfato , Amido/metabolismo
15.
Phytochemistry ; 164: 192-205, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31174083

RESUMO

The chemical composition of five marine microalgae (Dunaliella sp., Dunaliella salina, Chaetoceros calcitrans, Chaetoceros gracilis and Tisochrysis lutea) was investigated through nuclear magnetic resonance (NMR) spectroscopic study of the soluble material obtained by sequential extraction with hexane, ethyl acetate (AcOEt) and methanol of biomass from stationary phase cultures. Hexane extracted the major lipids present in the microalgae during the stationary phase of growth, which correspond to storage lipids. Triacylglycerols (TGs) were the only storage lipids produced by Dunaliella and Chaetoceros. In contrast, T. lutea predominantly stored polyunsaturated long-chain alkenones, with sterols also detected as minor components of the hexane extract. The molecular structure of brassicasterol was determined in T. lutea and the presence of squalene in this sample was also unequivocally detected. Monogalactosyldiacylglycerols (MGDGs) and pigments were concentrated in the AcOEt extracts. C. calcitrans and D. salina constituted an exception due to the high amount of TGs and glycerol produced, respectively, by these two strains. Chlorophylls a and b and ß-carotene were the major pigments synthesized by Dunaliella and chlorophyll a and fucoxanthin were the only pigments detected in Chaetoceros and T. lutea. Information concerning the acyl chains present in TGs and MGDGs as well as the positional distribution of acyl chains on the glycerol moiety was obtained by NMR analysis of hexane and AcOEt extracts, with results consistent with those expected for the genera studied. Fatty acid composition of TGs in the two Dunaliella strains was different, with polyunsaturated acyl chains almost absent in the storage lipids produced by D. salina. Except in C. calcitrans, the polar nature of soluble compounds was inferred through the relative extraction yield using methanol as the extraction solvent. Glycerol was the major component of this fraction for the Dunaliella strains. In T. lutea 1,4/2,5-cyclohexanetetrol (CHT) and dimethylsulfoniopropionate (DMSP) preponderated. CHT was also the major polyol present in the Chaetoceros strains in which DMSP was not detected, but prominent signals of 2,3-dihydroxypropane-1-sulfonate (DHSP) were observed in the 1H NMR spectra of methanolic extracts. The presence of DHSP confirms the production of this metabolite by diatoms. In addition, several other minor compounds (digalactosyldiacyglycerols (DGDGs), sulphoquinovosyldiacylglycerols (SQDGs), amino acids, carbohydrates, scyllo-inositol, mannitol, lactic acid and homarine) were also identified in the methanolic extracts. The antibacterial and antibiofilm activities of the extracts were tested. The AcOEt extract from C. gracilis showed a moderate antibiofilm activity.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Microalgas/química , Ressonância Magnética Nuclear Biomolecular , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Antifúngicos/isolamento & purificação , Fungos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Microalgas/metabolismo , Testes de Sensibilidade Microbiana , Conformação Molecular
16.
Mar Drugs ; 17(5)2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31137657

RESUMO

Microalgae represent a potential source of renewable nutrition and there is growing interest in algae-based dietary supplements in the form of whole biomass, e.g., Chlorella and Arthrospira, or purified extracts containing omega-3 fatty acids and carotenoids. The commercial production of bioactive compounds from microalgae is currently challenged by the biorefinery process. This review focuses on the biochemical composition of microalgae, the complexities of mass cultivation, as well as potential therapeutic applications. The advantages of open and closed growth systems are discussed, including common problems encountered with large-scale growth systems. Several methods are used for the purification and isolation of bioactive compounds, and many products from microalgae have shown potential as antioxidants and treatments for hypertension, among other health conditions. However, there are many unknown algal metabolites and potential impurities that could cause harm, so more research is needed to characterize strains of interest, improve overall operation, and generate safe, functional products.


Assuntos
Microalgas/química , Valor Nutritivo , Compostos Fitoquímicos/química , Reatores Biológicos , Suplementos Nutricionais , Humanos , Microalgas/crescimento & desenvolvimento , Compostos Fitoquímicos/isolamento & purificação
17.
Mar Drugs ; 17(5)2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31137922

RESUMO

Fucoxanthin (FX), a marine carotenoid found in macroalgae and microalgae, exhibits several beneficial effects to health. The anti-obesity activity of FX is well documented, but FX has not been mass-produced or applied extensively or commercially because of limited availability of raw materials and complex extraction techniques. In this study, we investigated the anti-obesity effect of standardized FX powder (Phaeodactylum extract (PE)) developed from microalga Phaeodactylum tricornutum as a commercial functional food. The effects of PE on adipogenesis inhibition in 3T3-L1 adipocytes and anti-obesity in high-fat diet (HFD)-fed C57BL/6J mice were evaluated. PE and FX dose-dependently decreased intracellular lipid contents in adipocytes without cytotoxicity. In HFD-fed obese mice, PE supplementation for six weeks decreased body weight, organ weight, and adipocyte size. In the serum parameter analysis, the PE-treated groups showed attenuation of lipid metabolism dysfunction and liver damage induced by HFD. In the liver, uncoupling protein-1 (UCP1) upregulation and peroxisome proliferator activated receptor γ (PPARγ) downregulation were detected in the PE-treated groups. Additionally, micro computed tomography revealed lower fat accumulation in PE-treated groups compared to that in the HFD group. These results indicate that PE exerts anti-obesity effects by inhibiting adipocytic lipogenesis, inducing fat mass reduction and decreasing intracellular lipid content, adipocyte size, and adipose weight.


Assuntos
Adipogenia/efeitos dos fármacos , Fármacos Antiobesidade/farmacologia , Produtos Biológicos/farmacologia , Estramenópilas/química , Xantofilas/farmacologia , Adipócitos/efeitos dos fármacos , Animais , Fármacos Antiobesidade/isolamento & purificação , Dieta Hiperlipídica , Alimento Funcional/análise , Camundongos Endogâmicos C57BL , Microalgas/química
18.
J Agric Food Chem ; 67(23): 6497-6507, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31083936

RESUMO

This experiment was to enrich docosahexaenoic acid (DHA) in broiler tissues through feeding a DHA-rich microalgal biomass and to explore the underlying metabolic and molecular mechanisms. Hatchling Cornish male broilers (total = 192) were fed a corn-soybean meal basal diet containing a full-fatted microalgae ( Aurantiochytrium) at 0%, 1%, 2%, and 4% for 6 weeks ( n = 6 cages/treatment, 8 birds/cage). The inclusion of microalgae led to dose-dependent ( P < 0.01) enrichments of DHA and decreases ( P < 0.01) of n-6/n-3 fatty acids (FAs) in plasma, liver, muscle, and adipose tissue. The microalgae supplementation also lowered ( P < 0.05-0.1) nonesterified FAs concentrations in the plasma, liver and adipose tissue. The mRNA abundances of most assayed genes involved in lipid metabolism were decreased ( P < 0.05) in the liver but elevated ( P < 0.05) in the adipose in response to the biomass supplementation. In conclusion, the biomass-resultant DHA enrichments in the broiler tissues were associated with a distinctive difference in the expression of lipid metabolism-controlling genes between the liver and adipose tissue.


Assuntos
Ração Animal/análise , Galinhas/metabolismo , Suplementos Nutricionais/análise , Ácidos Docosa-Hexaenoicos/metabolismo , Ácidos Graxos/metabolismo , Microalgas/metabolismo , Estramenópilas/metabolismo , Tecido Adiposo/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Galinhas/genética , Ácidos Graxos/química , Feminino , Fígado/metabolismo , Masculino , Microalgas/química , Músculos/metabolismo , Estramenópilas/química
19.
J Agric Food Chem ; 67(23): 6551-6558, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31099556

RESUMO

Unicellular microalgae are a valuable source of macro- and micronutrients. They contain, for example, proteins that are potentially useful as new emulsifiers. The aim of this study was to investigate the emulsifying properties of a less-refined lyophilized crude water-soluble extract (WSE), obtained from the heterotrophically cultivated microalga Chlorella protothecoides. Interfacial tension measurements indicated that mainly the proteins in the extract showed interfacial activity. O/W emulsions were prepared by high-pressure homogenization (1 000 bar, 3 passes) with 5.0 wt % of oil and 2.5 wt % of protein from Chlorella protothecoides, resulting in emulsions having a volume-based mean droplet diameter of d43 ≤ 1 µm and being stable for at least 7 days. Two different stress tests showed that ( i) protein-stabilized emulsions were resistant to very high salt concentrations (up to 500 mM NaCl), and ( ii) emulsions were stable over a very broad pH range of 2-9, with only minor changes in the particle size d43 (e.g. with an increase of only 300 nm when the pH was lowered from 5 to 4) compared to whey protein-stabilized emulsions. All WSE emulsions had monomodal particle size distributions and were macro- and microscopically stable during a storage of up to 7 days. The results indicate that the WSE of Chlorella protothecoides has remarkably good emulsifying properties and might be of use as a new emulsifier in various applications in which emulsions are exposed to a broad range of ionic strengths and pH values.


Assuntos
Chlorella/química , Emulsificantes/química , Microalgas/química , Extratos Vegetais/química , Emulsificantes/isolamento & purificação , Emulsões/química , Emulsões/isolamento & purificação , Concentração Osmolar , Extratos Vegetais/isolamento & purificação , Água/química
20.
Mar Pollut Bull ; 141: 404-415, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955750

RESUMO

Increased sediment loads within algal turfs, can be highly detrimental to coral reef systems. However, significant knowledge gaps remain in relation to sediment dynamics, especially linking suspended sediments, sedimentation and turf-bound sediments. To examine these links, a series of different methods for quantifying suspended sediments, sedimentation and the accumulation of turf sediments were compared, simultaneously, on an inner-shelf reef. We revealed that the amount and composition of sediment quantified using different methods varied markedly, with commonly employed measures of sedimentation failing to accurately reflect patterns of sediment accumulation in turfs. Our results highlighted the propensity for turfs to trap and retain sediments, with turfs accumulating approximately 2.6 times more sediment than traps, and 6 times more sediment than SedPods, over a seven-day period. This study highlights the major, but often overlooked, role that algal turfs can play in sediment dynamics on coral reefs.


Assuntos
Antozoários/crescimento & desenvolvimento , Recifes de Corais , Sedimentos Geológicos/química , Microalgas/química , Animais , Baías/química , Queensland
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