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1.
PLoS One ; 15(3): e0230569, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32218602

RESUMO

Different morphotypes of the abundant marine calcifying algal species Emiliania huxleyi are commonly linked to various degrees of E. huxleyi calcification, but few studies have been done to validate this assumption. This study investigated therefore whether E. huxleyi morphotypes can be related to coccolithophore calcification and coccolith mass. Samples from January (high productivity) and September (low productivity) 1997 at an open ocean and a coastal site near the Canary Islands were analysed using a combination of thickness measurements (Circular Polarizer Retardation estimates (CPR) method), Scanning Electron Microscope imaging, and Markov Chain Monte Carlo (MCMC) models. Mean E. huxleyi coccolith mass varied from a maximum of 2.9pg at the open ocean station in January to a minimum of 1.7pg in September at both stations. In contrast, overall calcite produced by E. huxleyi (assuming 23 coccoliths/cell) varied from a maximum of 2.6 µgL-1 at the coastal station in January to a minimum of 0.5 µgL-1 in September at the open ocean site. The relative abundance of "Overcalcified" Type A, Type A, Group B and malformed coccoliths was determined from SEM images. The mean coccolith mass of "Overcalcified" Type A was 2.0pg using the CPR-method, while mean mass of Type A and Group B coccoliths was determined using coccolith length measurements from SEM images and MCMC models relating thickness measurements to morphotype relative abundance. Type A cocccolith mass varied from a 1.6pg to 2.6pg and Group B coccolith mass varied from 1.5pg to 2.0pg. These results demonstrate that the coccolith mass of Type A, "Overcalcified" Type A, and Group B do not differ systematically and there is no systematic relationship between relative abundance of a morphotype and the overall calcite production of E. huxleyi. Therefore, morphotype appearance and relative abundance can not be uniformly used as reliable indicators of E. huxleyi calcification or calcite production.


Assuntos
Haptófitas/fisiologia , Carbonato de Cálcio/metabolismo , Haptófitas/química , Haptófitas/crescimento & desenvolvimento , Ilhas , Microscopia Eletrônica de Varredura , Método de Monte Carlo , Estações do Ano , Espanha , Temperatura
2.
Food Funct ; 10(11): 7333-7342, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31646314

RESUMO

Microalgae have strong potential as novel sources of nutraceuticals, as they contain significant amounts of highly valuable bioactive compounds. This study focuses on the bioprospection of biomass of the microalga Isochrysis galbana and its extracts (aqueous and ethanolic), determining total polyphenols, laminarin, fucoxanthin, coenzyme Q10, and ß-carotene contents, and also assessing several biological activities (antioxidant, cytotoxicity, and hypocholesterolemic). I. galbana exhibited high phenolic content, both in aqueous and ethanolic extracts. The microalgal freeze-dried biomass presented a low laminarin content and higher content of fucoxanthin (6.10 mg per g dw), and relevant ß-carotene and Coenzyme Q10 contents were detected. I. galbana aqueous extracts presented a high antioxidant capacity (approximately 90% inhibition by the ABTS method). Furthermore, I. galbana biomass and ethanolic extract showed significant cytotoxicity against HeLa human cervical cancer cells, with IC50 values of 0.32 and 0.28 mg ml-1 respectively, demonstrating potential for further anticancer studies. The aqueous extract of I. galbana induced a significant decrease of cholesterol absorption through Caco-2 monolayers, modelling the human intestinal barrier, which suggests that it may contribute to decreasing the dietary cholesterol absorption.


Assuntos
Suplementos Nutricionais , Haptófitas/química , Microalgas/química , Compostos de Bifenilo , Células CACO-2 , Sobrevivência Celular , Colesterol/metabolismo , Depuradores de Radicais Livres , Humanos , Picratos , Polifenóis , Ubiquinona/análogos & derivados , Ubiquinona/metabolismo , Xantofilas , beta Caroteno , beta-Glucanas
3.
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
4.
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
5.
Toxins (Basel) ; 11(5)2019 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-31060245

RESUMO

Harmful algal blooms of Prymnesium parvum have recurrently been associated with the killing of fish. The causative ichthyotoxic agents of this haptophyte are believed to be prymnesins, a group of supersized ladder-frame polyether compounds currently divided into three types. Here, the development of a quantitative method to assess the molar sum of prymnesins in water samples and in algal biomass is reported. The method is based on the derivatization of the primary amine group and subsequent fluorescence detection using external calibrants. The presence of prymnesins in the underivatized sample should be confirmed by liquid chromatography mass spectrometry. The method is currently only partly applicable to water samples due to the low amounts that are present. The growth and cellular toxin content of two B-type producing strains were monitored in batch cultures eventually limited by an elevated pH. The cellular toxin contents varied by a factor of ~2.5 throughout the growth cycle, with the highest amounts found in the exponential growth phase and the lowest in the stationary growth/death phases. The strain K-0081 contained ~5 times more toxin than K-0374. Further investigations showed that the majority of prymnesins were associated with the biomass (89% ± 7%). This study provides the basis for further investigations into the toxicity and production of prymnesins.


Assuntos
Haptófitas/química , Lipoproteínas/análise , Poluentes da Água/análise , Cromatografia Líquida de Alta Pressão , Haptófitas/metabolismo , Lipoproteínas/metabolismo , Espectrometria de Massas
6.
Faraday Discuss ; 216(0): 460-475, 2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31012452

RESUMO

The fucoxanthin-chlorophyll a protein from Emiliania huxleyi (E-FCP) is a member of the LHC family of light-harvesting proteins. It has a rather unusual pigment composition as its binds more Chl-c than Chl-a, and 19'-hexanoyloxyfucoxanthin (hFx) as the main carotenoid instead of fucoxanthin (Fx) typically found in various FCP complexes. The presence of a hexanoyloxy tail in hFx suppresses the charge transfer character of the S1/ICT state resulting in almost no effect of polarity on the excited state dynamics of hFx, strongly contrasting with the excited-state properties of Fx. Here we report on the dynamics of the energy transfer between hFx and Chl in E-FCP, and we compare it with Fx-Chl energy transfer in the FCP complex from Phaeodactylum tricornutum. In both complexes, the excited hFx (Fx) transfers energy from the S2 state with a sub-100 fs time constant and no effect of the hexanoyloxy tail on the efficiency of the S2 route was found. The energy transfer via the S1/ICT state has in E-FCP two channels characterized by 1.5 and 11 ps time constants, while for FCP these two channels operate with time constants of 0.8 and 4.5 ps. Thus, minimizing the charge transfer character of S1/ICT in hFx results in about twice slower energy transfer via the S1/ICT state, underlining the importance of the ICT state in facilitating carotenoid-Chl energy transfer in systems utilizing keto carotenoids as energy donors.


Assuntos
Carotenoides/química , Clorofila/química , Xantofilas/química , Sítios de Ligação , Transferência de Energia , Haptófitas/química , Conformação Molecular
7.
J Agric Food Chem ; 67(14): 3879-3889, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30920825

RESUMO

NMR spectroscopy coupled with multivariate data analysis techniques was applied to obtain meaningful information about nontargeted metabolic changes on  Isochrysis galbana upon acclimation to different environmental conditions at indoor lab-scale. The effects of temperature (from 15 to 30 °C) and incident irradiance (from 250 to 1600 µmol m-2 s-1) at a constant dilution rate of 0.3 h-1 were evaluated. High irradiances stimulated a decrease of chlorophyll a, fucoxanthin and amino acids content, and the conversion of polar fatty acids (PLs, GLs, DGDGs, SGDGs) to neutral fatty acids (saturated and unsaturated). High temperatures together with high irradiances decreased PUFAs concentration, including omega-3 fatty acids. Under low irradiance and temperature organic osmolytes (homarine, DMSP, GBT, and glycerol), and sugars (glucose, trehalose, and galactose) were also reduced.


Assuntos
Haptófitas/química , Haptófitas/efeitos da radiação , Espectroscopia de Ressonância Magnética/métodos , Metabolômica/métodos , Microalgas/química , Microalgas/efeitos da radiação , Aminoácidos/química , Aminoácidos/metabolismo , Clorofila A/química , Clorofila A/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados , Haptófitas/metabolismo , Microalgas/metabolismo , Temperatura
8.
Microb Ecol ; 77(3): 607-615, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30187089

RESUMO

Mixotrophic haptophytes comprise one of several important groups of mixotrophic nanoflagellates in the pelagic environment. This study aimed to investigate if phagotrophy in mixotrophic haptophytes is regulated by light or other factors in the surface (SE) and bottom (BE) of the euphotic zone in the subtropical northwestern Pacific Ocean. We estimated the rates of bacterial ingestion by haptophytes using fluorescently labeled bacteria (FLBs) and fluorescence in situ hybridization. Haptophyte diversity and abundance were also investigated in the same sampling area. The annual mean abundance of haptophytes was 419 ± 85.6 cells mL-1 in both SE and BE. Cells 3-5 µm in size were the dominant group in all haptophytes and accounted for majority of bacteria standing stock removed by haptophytes (53%). Most haptophyte ingestion rates (IRs) were not significantly different between the two layers (average SE ingestion rate: 12.5 ± 2.29 bac Hap-1 h-1; BE: 14.7 ± 3.03 bac Hap-1 h-1). Furthermore, the haptophyte IRs were negatively correlated with nitrate concentrations in the SE and positively correlated with bacterial abundances in the BE, which accounts for the significantly high IRs in August 2012 and 2013. These findings imply that mixotrophic haptophytes in this region had different factors affecting phagotrophy to adapt to the ambient light intensity alterations between SE and BE.


Assuntos
Haptófitas/fisiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Comportamento Alimentar , Haptófitas/química , Haptófitas/efeitos da radiação , Cinética , Luz , Oceano Pacífico
9.
Environ Microbiol ; 21(2): 541-556, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30461157

RESUMO

Factors that affect the respiration of organic carbon by marine bacteria can alter the extent to which the oceans act as a sink of atmospheric carbon dioxide. We designed seawater dilution experiments to assess the effect of pCO2 enrichment on heterotrophic bacterial community composition and metabolic potential in response to a pulse of phytoplankton-derived organic carbon. Experiments included treatments of elevated (1000 p.p.m.) and low (250 p.p.m.) pCO2 amended with 10 µmol L-1 dissolved organic carbon from Emiliana huxleyi lysates, and were conducted using surface-seawater collected from the South Pacific Subtropical Gyre. To assess differences in community composition and metabolic potential, shotgun metagenomic libraries were sequenced from low and elevated pCO2 treatments collected at the start of the experiment and following exponential growth. Our results indicate bacterial communities changed markedly in response to the organic matter pulse over time and were significantly affected by pCO2 enrichment. Elevated pCO2 also had disproportionate effects on the abundance of sequences related to proton pumps, carbohydrate metabolism, modifications of the phospholipid bilayer, resistance to toxic compounds and conjugative transfer. These results contribute to a growing understanding of the effects of elevated pCO2 on bacteria-mediated carbon cycling during phytoplankton bloom conditions in the marine environment.


Assuntos
Bactérias/metabolismo , Dióxido de Carbono/metabolismo , Compostos Orgânicos/metabolismo , Fitoplâncton/metabolismo , Água do Mar/microbiologia , Ciclo do Carbono/fisiologia , Ecossistema , Haptófitas/química , Processos Heterotróficos , Oceanos e Mares
10.
J Chromatogr A ; 1567: 90-98, 2018 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-30007794

RESUMO

Sea surface temperature determinations based on marine sedimentary C37 alkenone distributions have provided a wealth of data for paleoclimatic studies, including those performed at high resolution. The success of this approach results from several characteristics of alkenone compounds, e.g. their geochemical properties (such as unequivocal synthesis by certain widespread haptophyte algae, plus chemical stability/preservation of the original alkenone distributions during sedimentation), and their analytical properties (such as fast clean up procedures using alkaline hydrolysis of sediment extracts, followed by robust instrumental methods allowing large scale sample processing). Here we show that, in sediments under the influence of continental inputs, coelution of these compounds with cholest-5-enyl 3ß-undecenyl ether and 24-methylcholesta-5,22-dienyl 3ß-undecenyl ether deviate the SST measurements despite alkaline hydrolysis. Here, we report a new high performance liquid chromatrography fractionation method which eliminates these interfering compounds and gathers all the alkenones into a single fraction. These fractions can then be analysed by gas chromatography as in the initial approach, providing large amounts of data as required in high resolution studies.


Assuntos
Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Cetonas/análise , Temperatura , Atmosfera/química , Fracionamento Químico , Cromatografia Gasosa , Monitoramento Ambiental/instrumentação , Haptófitas/química , Cetonas/química
11.
Mar Pollut Bull ; 130: 170-178, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29866543

RESUMO

Phytoplankton alter their macromolecule composition in response to changing environmental conditions. Often these changes are consistent and can be used as indicators to predict their exposure to a given condition. FTIR-spectroscopy is a powerful tool that provides rapid snapshot of microbial samples. We used FTIR to develop signature macromolecular composition profiles of three cultures: Skeletonema costatum, Emiliania huxleyi, and Navicula sp., exposed to chemically enhanced water accommodated oil fraction (CEWAF) in artificial seawater and control. Using a multivariate model created with a Partial Least Square Discriminant Analysis of the FTIR-spectra, classification of CEWAF exposed versus control samples was possible. This model was validated using aggregate samples from a mesocosm study. Analysis of spectra and PCA-loadings plot showed changes to carbohydrates and proteins in response to CEWAF. Overall we developed a robust multivariate model that can be used to identify if a phytoplankton sample has been exposed to oil with dispersant.


Assuntos
Monitoramento Ambiental/métodos , Petróleo/toxicidade , Fitoplâncton/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Carboidratos , Diatomáceas/química , Diatomáceas/efeitos dos fármacos , Análise Discriminante , Haptófitas/química , Haptófitas/efeitos dos fármacos , Modelos Teóricos , Petróleo/análise , Poluição por Petróleo/efeitos adversos , Poluição por Petróleo/análise , Fitoplâncton/química , Análise de Componente Principal , Água do Mar , Água , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
12.
Mar Biotechnol (NY) ; 20(3): 304-312, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29619589

RESUMO

Coccolithophorids, unicellular marine microalgae, have calcified scales with elaborate structures, called coccoliths, on the cell surface. Coccoliths generally comprise a base plate, CaCO3, and a crystal coat consisting of acidic polysaccharides. In this study, the in vitro calcification conditions on the base plate of Pleurochrysis haptonemofera were examined to determine the functions of the base plate and acidic polysaccharides (Ph-PS-1, -2, and -3). When EDTA-treated coccoliths (acidic polysaccharide-free base plates) or low pH-treated coccoliths (whole acidic polysaccharide-containing base plates) were used, mineralization was not detected on the base plate. In contrast, in the case of coccoliths which were decalcified by lowering of the pH and then treated with urea (Ph-PS-2-containing base plates), distinct aggregates, probably containing CaCO3, were observed only on the rim of the base plates. Energy dispersive X-ray spectroscopy (EDS) confirmed that the aggregates contained Ca and O, although X-ray diffraction analysis did not reveal any evidence of crystalline materials. Also, in vitro mineralization experiments performed on EDTA-treated coccoliths using isolated acidic polysaccharides demonstrated that the Ca-containing aggregates were markedly formed only in the presence of Ph-PS-2. Furthermore, in vitro mineralization experiments conducted on protein-extracted base plates suggested that the coccolith-associated protein(s) are involved in the Ca deposition. These findings suggest that Ph-PS-2 associated with the protein(s) on the base plate rim initiates Ca2+ binding at the beginning of coccolith formation, and some other factors are required for subsequent calcite formation.


Assuntos
Cálcio/química , Haptófitas/metabolismo , Polissacarídeos/química , Calcificação Fisiológica , Carbonato de Cálcio/química , Haptófitas/química , Espectrometria por Raios X
13.
Molecules ; 23(4)2018 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-29641444

RESUMO

By their autotrophic nature and their molecular richness, microalgae are serious assets in the context of current environmental and societal challenges. Some species produce both omega-3 long chain polyunsaturated fatty acids (PUFAs) and xanthophylls, two molecular families widely studied for their bioactivities in the fields of nutrition and cosmetics. Whereas most studies separately deal with the two families, synergies could be exploited with extracts containing both PUFAs and xanthophylls. The purpose of our work was to determine cost effective and eco-friendly parameters for their co-extraction. The effect of several parameters (solvent, solvent/biomass ratio, temperature, duration) were studied, using two microalgal species, the non-calcifying Haptophyta Tisochrysis lutea, and the diatom Phaeodactylum tricornutum, that presents a silicified frustule. Analyses of PUFAs and fucoxanthin (Fx), the main xanthophyll, allowed to compare kinetics and extraction yields between experimental protocols. Co-extraction yields achieved using 96% ethanol as solvent were 100% for Fx and docosahexaenoic acid (DHA) in one hour from T. lutea biomass, and respectively 95% and 89% for Fx and eicosapentaenoic acid (EPA) in eight hours from P. tricornutum. These conditions are compatible with industrial applications.


Assuntos
Ácidos Graxos Insaturados/isolamento & purificação , Microalgas/química , Xantofilas/isolamento & purificação , Biomassa , Diatomáceas/química , Ácidos Graxos Insaturados/química , Haptófitas/química , Solventes , Temperatura , Fatores de Tempo
14.
Food Funct ; 9(3): 1683-1691, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29473927

RESUMO

The formation and accumulation of advanced glycation endproducts (AGEs) have been implicated in the pathogenesis of many chronic diseases, such as aging, Alzheimer's disease, diabetes and diabetic complications. The present study was aimed to investigate the inhibitory effects of the extracts from nine microalgae on the formation of AGEs by using in vitro models and identify key antiglycation constituents of the microalgae. A BSA-glucose model with simulated physiological conditions was used to evaluate the inhibitory effect on total AGE formation. A BSA-MGO model was used to study the inhibitory activity against the dicarbonyl-induced AGE formation. The results showed that the aqueous acetone extracts exhibited stronger antiglycation activity than the other extracts (ethyl acetate and dichloromethane) and that the marine microalgal extracts were generally more effective than the freshwater ones. Their inhibitory rates ranged from >60% to 90% when used at a concentration of 0.5 mg mL-1. HPLC-DAD and UPLC-Q-TOF-MSE analyses revealed that fucoxanthin was likely the principal component which contributed to the observed antiglycation activity. Further analysis established a highly significant positive correlation (R2 > 0.95) between the fucoxanthin content and the antiglycation activity of the aqueous acetone extracts. This is the first report on the antiglycation activity of fucoxanthin. The findings of the present study have not only identified a promising inhibitor of AGE formation, but have also identified a valuable natural source of this phytochemical which possesses great potential to be developed as functional food ingredients and pharmaceutical products to help reduce health risks associated with AGEs.


Assuntos
Chlorella vulgaris/química , Diatomáceas/química , Produtos Finais de Glicação Avançada/química , Haptófitas/química , Microalgas/química , Extratos Vegetais/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Estrutura Molecular , Extratos Vegetais/isolamento & purificação
15.
Mol Med Rep ; 17(1): 2044-2050, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29257215

RESUMO

Fermented microalgae Pavlova lutheri (P. lutheri), the product of Hansenula polymorpha fermentation, exhibited an increase in alkaline phosphatase (ALP) activity in MG­63 osteoblastic cells when compared to that of non­fermented P. lutheri. Fractionation of the fermented P. lutheri resulted in identification of the active peptide [peptide of P. lutheri fermentation (PPLF)] with the sequence of EPQWFL. PPLF significantly increased ALP release from MG­63 cells and mineralization in a dose­dependent manner. In addition, the intracellular levels of ALP and osteocalcin (OCN) proteins were augmented by PPLF treatment. To identify the molecular mechanism underlying the effect of PPLF on osteoblastic differentiation, the phosphorylation levels of the mitogen­activated protein kinases, p38, extracellular signal­regulated kinases 1/2 and Jun, and nuclear factor (NF)­κB were determined following PPLF treatment and the differences in expression were analyzed using p38 and NF­κB selective inhibitors. These results concluded that PPLF from fermented P. lutheri induced osteoblastic differentiation by increasing ALP and OCN release in MG­63 cells via the p38/p65 signaling pathway, indicating that PPLF supplement may be effective for therapeutic application in the field of bone health.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Haptófitas/química , Microalgas/química , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Peptídeos/farmacologia , Fosfatase Alcalina/metabolismo , Calcificação Fisiológica/efeitos dos fármacos , Linhagem Celular , Fermentação , Humanos , Osteoblastos/citologia , Osteocalcina/metabolismo , Peptídeos/química
16.
PLoS One ; 12(10): e0185655, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29036179

RESUMO

The formation of the coccolith biominerals by a group of marine algae (the Coccolithophores) offers fascinating research avenues both from the biological and geological sides. It is surprising how biomineralisation by a key phytoplanktonic group remains underconstrained, yet is influential on ocean alkalinity and responsible for the built up of our paleoclimatic archive over the last 200 Myrs. Here, we report two close relative coccolith taxa exhibiting substantial bioaccumulation of strontium: Scyphosphaera and Pontosphaera grown in the laboratory or retrieved from Pliocene sediments. This strontium enrichment relative to calcium is one order of magnitude greater than reported in other coccoliths of the orders Isochrysidales and Coccolithales, and extends well beyond established controls on Sr/Ca ratios by temperature and growth rate. We discuss this prominent vital effect in relation with possible specific uptake of strontium relative to calcium from the extracellular environment to the coccolith vesicle in coccolithophores excreting very large scale coccoliths. The report of Sr-rich biominerals challenges our current understanding of the cellular acquisition and intracellular trafficking of alkaline earth cations in phytoplanktonic calcifying eukaryotic algae. The presence of Sr-rich coccolith species in the geological record has to be quantitatively considered in future Sr/Ca-based palaeoceanographic reconstruction.


Assuntos
Calcificação Fisiológica , Fósseis , Haptófitas/metabolismo , Estrôncio/metabolismo , Cálcio/análise , Cálcio/metabolismo , Haptófitas/química , Haptófitas/crescimento & desenvolvimento , Haptófitas/ultraestrutura , Microscopia Eletrônica de Varredura , Oceanos e Mares , Sicília , Análise Espectral , Estrôncio/análise , Temperatura , Difração de Raios X
17.
Molecules ; 22(7)2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28671567

RESUMO

Diacronema vlkianum is a marine microalgae for which supposed health promoting effects have been claimed based on its phytochemical composition. The potential use of its biomass as health ingredient, including detox-shakes, and the lack of bioavailability studies were the main concerns. In order to evaluate the microalgae-biomass assimilation and its health-benefits, single-dose (CD1-mice) studies were followed by 66-days repeated-dose study in Wistar rats with the highest tested single-dose of microalgae equivalent to 101 mg/kg eicosapentaenoic acid + docosahexaenoic acid (EPA+DHA). Microalgae-supplementation modulated EPA and docosapentaenoic acid enrichment at arachidonic acid content expenditure in erythrocytes and liver, while increasing EPA content of heart and adipose tissues of rats. Those fatty acid (FA) changes confirmed the D. vlkianum-biomass FA assimilation. The principal component analyses discriminated brain from other tissues, which formed two other groups (erythrocytes, liver, and heart separated from kidney and adipose tissues), pointing to a distinct signature of FA deposition for the brain and for the other organs. The improved serum lipid profile, omega-3 index and erythrocyte plasticity support the cardiovascular benefits of D. vlkianum. These results bolster the potential of D. vlkianum-biomass to become a "heart-healthy" food supplement providing a safe and renewable source of bioavailable omega-3 FA.


Assuntos
Ácidos Docosa-Hexaenoicos/química , Ácido Eicosapentaenoico/química , Ácidos Graxos/análise , Haptófitas/química , Microalgas/química , Tecido Adiposo/química , Animais , Organismos Aquáticos/química , Biomassa , Suplementos Nutricionais/análise , Eritrócitos/química , Fígado/química , Masculino , Miocárdio/química , Ratos , Ratos Wistar
18.
Phytochemistry ; 139: 25-32, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28407491

RESUMO

Plant sterols have become well-known to promote cardiovascular health through the reduction of low density lipoprotein cholesterol in the blood. Plant sterols also have anti-inflammatory, anti-cancer, anti-oxidative and anti-atherogenicity activities. Microalgae have the potential to become a useful alternative source of plant sterols with several species reported to have higher concentrations than current commercial ones. In order to increase phytosterol production and optimise culture conditions, the high sterol producer Pavlova lutheri was treated in different dosages (50-250 mJ m-2) of UV-C radiation and several concentrations (1-500 µmol/L) of hydrogen peroxide (H2O2) and the sterol contents were quantified for two days after the treatments. The contents of malondialdehyde (MDA) superoxide dismutase (SOD) as indications of cell membrane damage by lipid peroxidation and repair of oxidative stress, respectively, were measured. Higher activities of SOD and MDA were observed in the treated biomass when compared to the controls. Total sterols increased in P. lutheri due to UV-C radiation (at 100 mJ m-2) but not in response to H2O2 treatment. Among the nineteen sterol compounds identified in P. lutheri, poriferasterol, epicampesterol, methylergostenol, fungisterol, dihydrochondrillasterol, and chondrillasterol increased due to UV-C radiation. Therefore, UV-C radiation can be a useful tool to boost industrial phytosterol production from P. lutheri.


Assuntos
Microalgas/química , Esteróis , Raios Ultravioleta , Haptófitas/química , Peróxido de Hidrogênio/farmacologia , Peroxidação de Lipídeos , Estresse Oxidativo , Esteróis/isolamento & purificação , Esteróis/metabolismo , Esteróis/farmacologia , Esteróis/efeitos da radiação
19.
Mar Drugs ; 16(1)2017 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-29295585

RESUMO

Chronic inflammatory skin diseases such as psoriasis have a significant impact on society. Currently, the major topical treatments have many side effects, making their continued use in patients difficult. Microalgae have emerged as a source of bio-active molecules such as glycolipids with potent anti-inflammatory properties. We aimed to investigate the effects of a glycolipid (MGMG-A) and a glycolipid fraction (MGDG) obtained from the microalga Isochrysis galbana on a TPA-induced epidermal hyperplasia murine model. In a first set of experiments, we examined the preventive effects of MGMG-A and MGDG dissolved in acetone on TPA-induced hyperplasia model in mice. In a second step, we performed an in vivo permeability study by using rhodamine-containing cream, ointment, or gel to determinate the formulation that preserves the skin architecture and reaches deeper. The selected formulation was assayed to ensure the stability and enhanced permeation properties of the samples in an ex vivo experiment. Finally, MGDG-containing cream was assessed in the hyperplasia murine model. The results showed that pre-treatment with acetone-dissolved glycolipids reduced skin edema, epidermal thickness, and pro-inflammatory cytokine production (TNF-α, IL-1ß, IL-6, IL-17) in epidermal tissue. The in vivo and ex vivo permeation studies showed that the cream formulation had the best permeability profile. In the same way, MGDG-cream formulation showed better permeation than acetone-dissolved preparation. MGDG-cream application attenuated TPA-induced skin edema, improved histopathological features, and showed a reduction of the inflammatory cell infiltrate. In addition, this formulation inhibited epidermal expression of COX-2 in a similar way to dexamethasone. Our results suggest that an MGDG-containing cream could be an emerging therapeutic strategy for the treatment of inflammatory skin pathologies such as psoriasis.


Assuntos
Glicolipídeos/administração & dosagem , Glicolipídeos/uso terapêutico , Haptófitas/química , Hiperplasia/prevenção & controle , Dermatopatias/prevenção & controle , Administração Tópica , Animais , Sobrevivência Celular/efeitos dos fármacos , Citocinas/análise , Citocinas/biossíntese , Composição de Medicamentos , Feminino , Glicolipídeos/farmacocinética , Humanos , Hiperplasia/induzido quimicamente , Hiperplasia/patologia , Queratinócitos/efeitos dos fármacos , Camundongos , Pomadas , Pele/patologia , Absorção Cutânea , Dermatopatias/induzido quimicamente , Dermatopatias/patologia , Acetato de Tetradecanoilforbol
20.
Nat Commun ; 7: 13144, 2016 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-27782214

RESUMO

Unicellular phytoplanktonic algae (coccolithophores) are among the most prolific producers of calcium carbonate on the planet, with a production of ∼1026 coccoliths per year. During their lith formation, coccolithophores mainly employ coccolith-associated polysaccharides (CAPs) for the regulation of crystal nucleation and growth. These macromolecules interact with the intracellular calcifying compartment (coccolith vesicle) through the charged carboxyl groups of their uronic acid residues. Here we report the isolation of CAPs from modern day coccolithophores and their prehistoric predecessors and we demonstrate that their uronic acid content (UAC) offers a species-specific signature. We also show that there is a correlation between the UAC of CAPs and the internal saturation state of the coccolith vesicle that, for most geologically abundant species, is inextricably linked to carbon availability. These findings suggest that the UAC of CAPs reports on the adaptation of coccolithogenesis to environmental changes and can be used for the estimation of past CO2 concentrations.


Assuntos
Carbonato de Cálcio/química , Carbono/química , Haptófitas/química , Fitoplâncton/química , Polissacarídeos/química , Ácidos Urônicos/química , Adaptação Fisiológica , Calcificação Fisiológica , Carbonato de Cálcio/história , Carbonato de Cálcio/metabolismo , Carbono/história , Carbono/metabolismo , Dióxido de Carbono/química , Dióxido de Carbono/história , Dióxido de Carbono/metabolismo , Cristalização , Fósseis/história , Haptófitas/classificação , Haptófitas/metabolismo , História Antiga , Paleontologia , Fitoplâncton/classificação , Fitoplâncton/metabolismo , Polissacarídeos/história , Polissacarídeos/metabolismo , Especificidade da Espécie , Ácidos Urônicos/história , Ácidos Urônicos/metabolismo
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