Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.180
Filtrar
1.
Mar Drugs ; 18(10)2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32993146

RESUMO

For a long time, algal chemistry from terrestrial to marine or freshwater bodies, especially chlorophytes, has fascinated numerous investigators to develop new drugs in the nutraceutical and pharmaceutical industries. As such, chlorophytes comprise a diverse structural class of secondary metabolites, having functional groups that are specific to a particular source. All bioactive compounds of chlorophyte are of great interest due to their supplemental/nutritional/pharmacological activities. In this review, a detailed description of the chemical diversity of compounds encompassing alkaloids, terpenes, steroids, fatty acids and glycerides, their subclasses and their structures are discussed. These promising natural products have efficiency in developing new drugs necessary in the treatment of various deadly pathologies (cancer, HIV, SARS-CoV-2, several inflammations, etc.). Marine chlorophyte, therefore, is portrayed as a pivotal treasure in the case of drugs having marine provenience. It is a domain of research expected to probe novel pharmaceutically or nutraceutically important secondary metabolites resulting from marine Chlorophyta. In this regard, our review aims to compile the isolated secondary metabolites having diverse chemical structures from chlorophytes (like Caulerpa ssp., Ulva ssp., Tydemania ssp., Penicillus ssp., Codium ssp., Capsosiphon ssp., Avrainvillea ssp.), their biological properties, applications and possible mode of action.


Assuntos
Produtos Biológicos/farmacologia , Clorófitas/química , Clorófitas/metabolismo , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Antivirais/química , Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , Produtos Biológicos/química , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Humanos , Neoplasias/tratamento farmacológico , Pandemias , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia
2.
Int J Mol Sci ; 21(11)2020 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-32503354

RESUMO

Monoclonal antibodies, engineered antibodies, and antibody fragments have become important biological therapeutic platforms. The IgG format with bivalent binding sites has a modular structure with different biological roles, i.e., effector and binding functions, in different domains. We demonstrated the reconstruction of an IgG-like domain structure in vitro by protein ligation using protein trans-splicing. We produced various binding domains to replace the binding domain of IgG from Escherichia coli and the Fc domain of human IgG from Brevibacillus choshinensis as split-intein fusions. We showed that in vitro protein ligation could produce various Fc-fusions at the N-terminus in vitro from the independently produced domains from different organisms. We thus propose an off-the-shelf approach for the combinatorial production of Fc fusions in vitro with several distinct binding domains, particularly from naturally occurring binding domains. Antiviral lectins from algae are known to inhibit virus entry of HIV and SARS coronavirus. We demonstrated that a lectin could be fused with the Fc-domain in vitro by protein ligation, producing an IgG-like molecule as a "lectibody". Such an Fc-fusion could be produced in vitro by this approach, which could be an attractive method for developing potential therapeutic agents against rapidly emerging infectious diseases like SARS coronavirus without any genetic fusion and expression optimization.


Assuntos
Fragmentos Fc das Imunoglobulinas/metabolismo , Lectinas/metabolismo , Trans-Splicing , Brevibacillus/imunologia , Clorófitas/metabolismo , HIV/fisiologia , Humanos , Fragmentos Fc das Imunoglobulinas/genética , Imunoglobulina G/química , Imunoglobulina G/metabolismo , Lectinas/genética , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/farmacologia , Vírus da SARS/fisiologia , Internalização do Vírus/efeitos dos fármacos
3.
Proc Natl Acad Sci U S A ; 117(24): 13588-13595, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482859

RESUMO

Viruses, microbes, and host macroorganisms form ecological units called holobionts. Here, a combination of metagenomic sequencing, metabolomic profiling, and epifluorescence microscopy was used to investigate how the different components of the holobiont including bacteria, viruses, and their associated metabolites mediate ecological interactions between corals and turf algae. The data demonstrate that there was a microbial assemblage unique to the coral-turf algae interface displaying higher microbial abundances and larger microbial cells. This was consistent with previous studies showing that turf algae exudates feed interface and coral-associated microbial communities, often at the detriment of the coral. Further supporting this hypothesis, when the metabolites were assigned a nominal oxidation state of carbon (NOSC), we found that the turf algal metabolites were significantly more reduced (i.e., have higher potential energy) compared to the corals and interfaces. The algae feeding hypothesis was further supported when the ecological outcomes of interactions (e.g., whether coral was winning or losing) were considered. For example, coral holobionts losing the competition with turf algae had higher Bacteroidetes-to-Firmicutes ratios and an elevated abundance of genes involved in bacterial growth and division. These changes were similar to trends observed in the obese human gut microbiome, where overfeeding of the microbiome creates a dysbiosis detrimental to the long-term health of the metazoan host. Together these results show that there are specific biogeochemical changes at coral-turf algal interfaces that predict the competitive outcomes between holobionts and are consistent with algal exudates feeding coral-associated microbes.


Assuntos
Antozoários/metabolismo , Clorófitas/metabolismo , Animais , Antozoários/química , Antozoários/microbiologia , Antozoários/parasitologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Clorófitas/química , Recifes de Corais , Ecossistema , Metagenômica , Microbiota
4.
Nat Commun ; 11(1): 2527, 2020 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32433543

RESUMO

We present the first estimate of green snow algae community biomass and distribution along the Antarctic Peninsula. Sentinel 2 imagery supported by two field campaigns revealed 1679 snow algae blooms, seasonally covering 1.95 × 106 m2 and equating to 1.3 × 103 tonnes total dry biomass. Ecosystem range is limited to areas with average positive summer temperatures, and distribution strongly influenced by marine nutrient inputs, with 60% of blooms less than 5 km from a penguin colony. A warming Antarctica may lose a majority of the 62% of blooms occupying small, low-lying islands with no high ground for range expansion. However, bloom area and elevation were observed to increase at lower latitudes, suggesting that parallel expansion of bloom area on larger landmasses, close to bird or seal colonies, is likely. This increase is predicted to outweigh biomass lost from small islands, resulting in a net increase in snow algae extent and biomass as the Peninsula warms.


Assuntos
Carbono/metabolismo , Clorófitas/metabolismo , Distribuição Animal , Animais , Regiões Antárticas , Biomassa , Aves/crescimento & desenvolvimento , Carbono/análise , Sequestro de Carbono , Clorófitas/classificação , Clorófitas/crescimento & desenvolvimento , Ecossistema , Eutrofização , Ilhas , Tecnologia de Sensoriamento Remoto , Focas Verdadeiras/crescimento & desenvolvimento , Estações do Ano , Spheniscidae/crescimento & desenvolvimento
5.
Ecotoxicol Environ Saf ; 196: 110552, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32259759

RESUMO

Nowadays, numerous studies have focused on the newly developed technologies for the thorough removal of tetracyclines (TCs). However, it is often ignored that the parent TCs have limited stability in aquatic environments. Thus, this study selected green alga Chlamydomonas reinhardtii with high chlorophyll content to rapidly degrade chlortetracycline (CTC) into products with low toxicity. As the results shown, the half-life times of CTC (1 × 10-6 mol/L) decreased from 10.35 h to 2.55 h by the presence of C. reinhardtii at 24±1 °C with 12/12 h dark/light cycle. The main transformation products were iso-chlortetracycline (ICTC), 4-epi-iso-chlortetracycline (EICTC), and other degradation products with lower molecular weight. The toxicity evaluation shows that the negative effects of CTC on growth rate and soluble protein content of green algae were significantly alleviated after the enhanced degradation treatment, while the generation of reactive oxygen species (ROS) and antioxidant response in algal cells returned to normal levels. The chlorophyll of algae played an important role of photosensitizer, which catalyzed the photo-induced electron/energy transfer of CTC degradation. The ROS generation of algae also was also inseparable from the enhanced degradation of CTC, especially when the chlorophyll was damaged at the high CTC concentration. Based on these results, we can better select suitable algal species to further strengthen the degradation of antibiotics and effectively reduce the environmental risk of CTC in aqueous system.


Assuntos
Antibacterianos/análise , Chlamydomonas reinhardtii/metabolismo , Clortetraciclina/análise , Poluentes Químicos da Água/análise , Antibacterianos/metabolismo , Antibacterianos/toxicidade , Antioxidantes/metabolismo , Biodegradação Ambiental , Chlamydomonas reinhardtii/efeitos dos fármacos , Clorofila/metabolismo , Clorófitas/metabolismo , Clortetraciclina/metabolismo , Clortetraciclina/toxicidade , Inativação Metabólica/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
6.
PLoS One ; 15(3): e0229148, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32160215

RESUMO

Lake Lesser Prespa in Greece is a vital breeding habitat for the Dalmatian and Great White Pelican and a shelter for numerous rare and endemic species. However, eutrophication processes are distressing the lake system and the outbreaks of cyanobacterial blooms during the warm months may pose a threat to aquatic organisms due to the presence of microcystins (MCs). In this study we hypothesize that nutrients (eutrophication), nutrient-rich pelican droppings (guanotrophication) and warming (climate change) can affect the algal growth and MCs production in the water layer of Lake Lesser Prespa. Seston collected from three lake sites was incubated at ambient (20°C) and high (30°C) temperature with or without the addition of nutrients (nitrogen (N), phosphorus (P)), or pelican droppings. Results showed increased chlorophyll-a at higher temperature (30°C). N addition yielded higher chlorophyll-a levels than the non-treated water or when only P was added. The addition of both N and P as well as the addition of pelican dropping resulted in the highest chlorophyll-a at both temperatures. Notably, in the dropping-treatments, cyanobacteria and MCs were promoted while changes were evoked in the relative contribution of toxic MC-variants. Guanotrophication may thus influence the cyanobacterial dynamics and most likely their toxicity profile at Lesser Prespa.


Assuntos
Clorófitas , Mudança Climática , Cianobactérias , Eutrofização , Lagos , Microcistinas/metabolismo , Animais , Aves/metabolismo , Clorófitas/crescimento & desenvolvimento , Clorófitas/metabolismo , Cianobactérias/crescimento & desenvolvimento , Cianobactérias/metabolismo , Fezes , Grécia , Microcistinas/toxicidade , Temperatura
7.
Biochim Biophys Acta Bioenerg ; 1861(5-6): 148186, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32171793

RESUMO

The light-harvesting complexes II (LHCIIs) of spinach and Bryopsis corticulans as a green alga are similar in structure, but differ in carotenoid (Car) and chlorophyll (Chl) compositions. Carbonyl Cars siphonein (Spn) and siphonaxanthin (Spx) bind to B. corticulans LHCII likely in the sites as a pair of lutein (Lut) molecules bind to spinach LHCII in the central domain. To understand the light-harvesting and photoprotective properties of the algal LHCII, we compared its excitation dynamics and relaxation to those of spinach LHCII been well documented. It was found that B. corticulans LHCII exhibited a substantially longer chlorophyll (Chl) fluorescence lifetime (4.9 ns vs 4.1 ns) and a 60% increase of the fluorescence quantum yield. Photoexcitation populated 3Car* equally between Spn and Spx in B. corticulans LHCII, whereas predominantly at Lut620 in spinach LHCII. These results prove the functional differences of the LHCIIs with different Car pairs and Chl a/b ratios: B. corticulans LHCII shows the enhanced blue-green light absorption, the alleviated quenching of 1Chl*, and the dual sites of quenching 3Chl*, which may facilitate its light-harvesting and photoprotection functions. Moreover, for both types of LHCIIs, the triplet excitation profiles revealed the involvement of extra 3Car* formation mechanisms besides the conventional Chl-to-Car triplet transfer, which are discussed in relation to the ultrafast processes of 1Chl* quenching. Our experimental findings will be helpful in deepening the understanding of the light harvesting and photoprotection functions of B. corticulans living in the intertidal zone with dramatically changing light condition.


Assuntos
Clorófitas/metabolismo , Complexos de Proteínas Captadores de Luz/metabolismo , Água do Mar , Carotenoides/metabolismo , Clorofila/metabolismo , Cinética , Espectrometria de Fluorescência , Spinacia oleracea/metabolismo
8.
Biochim Biophys Acta Bioenerg ; 1861(7): 148191, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32201306

RESUMO

Light-harvesting complex II (LHCII) from the marine green macroalga Bryopsis corticulans is spectroscopically characterized to understand the structural and functional changes resulting from adaptation to intertidal environment. LHCII is homologous to its counterpart in land plants but has a different carotenoid and chlorophyll (Chl) composition. This is reflected in the steady-state absorption, fluorescence, linear dichroism, circular dichroism and anisotropic circular dichroism spectra. Time-resolved fluorescence and two-dimensional electronic spectroscopy were used to investigate the consequences of this adaptive change in the pigment composition on the excited-state dynamics. The complex contains additional Chl b spectral forms - absorbing at around 650 nm and 658 nm - and lacks the red-most Chl a forms compared with higher-plant LHCII. Similar to plant LHCII, energy transfer between Chls occurs on timescales from under hundred fs (mainly from Chl b to Chl a) to several picoseconds (mainly between Chl a pools). However, the presence of long-lived, weakly coupled Chl b and Chl a states leads to slower exciton equilibration in LHCII from B. corticulans. The finding demonstrates a trade-off between the enhanced absorption of blue-green light and the excitation migration time. However, the adaptive change does not result in a significant drop in the overall photochemical efficiency of Photosystem II. These results show that LHCII is a robust adaptable system whose spectral properties can be tuned to the environment for optimal light harvesting.


Assuntos
Clorófitas/metabolismo , Transferência de Energia , Complexos de Proteínas Captadores de Luz/metabolismo , Dicroísmo Circular , Espectrometria de Fluorescência , Temperatura , Fatores de Tempo
9.
Aquat Toxicol ; 222: 105450, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32106005

RESUMO

The toxicity of heavy metals in algal monocultures is well studied and is mediated by reactive oxygen and nitrogen species (ROS/RNS). However, little is known about the toxicity of heavy metals and the mechanisms involved in mixed cultures. Here we examine the oxidative stress and toxic effects of Cu2+ on the green alga Dunaliella salina (DS) and the cyanobacteria Synecochoccus elongatus (SE) in both mono- and mixed cultures. We find that both species benefit in mixed cultures and acquire higher resistance to Cu2+ toxicity, with a particularly marked effect on SE. DS has a larger surface area than SE, so increases in the number of DS cells compared to SE diminishes the proportion of SE surface area exposed to Cu2+, and contributes to increasing cyanobacterial resistance in mixed cultures. However, these mixed cultures also display as an unexpected property an increased resistance of DS in mixed cultures. SE and DS cells showed significant differences on the kinetics of H2O2 production and antioxidant capacities. The integrated (overall) redox response of mixed cultures, in terms of total amount of H2O2 produced, was proportional to the total surface area of algal species exposed to Cu2+, independent of algal composition in mixed systems. However, mixed cultures display emergent properties, as the time course of H2O2 accumulation is not a simple function of the composition of the mixed cultures. Emergent properties are also observed in the speed of membrane lipid oxidation by the two species, as measured using mixed cultures in which only one of the two species is labeled using the membrane oxidation indicator C11-BODIPY581/591. We suggest that, in addition to H2O2¸ other redox signals (e.g. NO) and allelochemicals (auxins, cytokinins, etc.) may be used to construct a complex inter-species communication network. This could allow mixed algal systems, whatever their composition, to integrate their cellular responses and perform as a coherent unit against toxic Cu2+ ions.


Assuntos
Clorófitas/efeitos dos fármacos , Cobre/toxicidade , Cianobactérias/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Antioxidantes/metabolismo , Clorófitas/metabolismo , Cianobactérias/metabolismo , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Especificidade da Espécie , Poluentes Químicos da Água/toxicidade
10.
PLoS One ; 15(2): e0228448, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32017799

RESUMO

Upwelling is an important source of inorganic nutrients in marine systems, yet little is known about how gradients in upwelling affect primary producers on coral reefs. The Southern Line Islands span a natural gradient of inorganic nutrient concentrations across the equatorial upwelling region in the central Pacific. We used this gradient to test the hypothesis that benthic autotroph ecophysiology is enhanced on nutrient-enriched reefs. We measured metabolism and photophysiology of common benthic taxa, including the algae Porolithon, Avrainvillea, and Halimeda, and the corals Pocillopora and Montipora. We found that temperature (27.2-28.7°C) was inversely related to dissolved inorganic nitrogen (0.46-4.63 µM) and surface chlorophyll a concentrations (0.108-0.147 mg m-3), which increased near the equator. Contrary to our prediction, ecophysiology did not consistently track these patterns in all taxa. Though metabolic rates were generally variable, Porolithon and Avrainvillea photosynthesis was highest at the most productive and equatorial island (northernmost). Porolithon photosynthetic rates also generally increased with proximity to the equator. Photophysiology (maximum quantum yield) increased near the equator and was highest at northern islands in all taxa. Photosynthetic pigments also were variable, but chlorophyll a and carotenoids in Avrainvillea and Montipora were highest at the northern islands. Phycobilin pigments of Porolithon responded most consistently across the upwelling gradient, with higher phycoerythrin concentrations closer to the equator. Our findings demonstrate that the effects of in situ nutrient enrichment on benthic autotrophs may be more complex than laboratory experiments indicate. While upwelling is an important feature in some reef ecosystems, ancillary factors may regulate the associated consequences of nutrient enrichment on benthic reef organisms.


Assuntos
Antozoários/crescimento & desenvolvimento , Clorófitas/crescimento & desenvolvimento , Nitrogênio/metabolismo , Rodófitas/crescimento & desenvolvimento , Animais , Antozoários/metabolismo , Processos Autotróficos , Clorófitas/metabolismo , Recifes de Corais , Ecossistema , Ilhas do Pacífico , Fotossíntese , Rodófitas/metabolismo , Temperatura
11.
BMC Genomics ; 21(1): 115, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32013861

RESUMO

BACKGROUND: Dunaliella salina is a good model organism for studying salt stress. In order to have a global understanding of the expression profiles of Dunaliella salina in response to hypersaline stress, we performed quantitative transcriptomic analysis of Dunaliella salina under hypersaline stress (2.5 M NaCl) of different time duration by the second and third generation sequencing method. RESULTS: Functional enrichment of the up-regulated genes was used to analyze the expression profiles. The enrichment of photosynthesis was observed, accompanied by enrichments of carbon fixation, pigment biosynthetic process and heme biosynthetic process, which also imply the enhancement of photosynthesis. Genes responsible for starch hydrolysis and glycerol synthesis were significantly up-regulated. The enrichment of biosynthesis of unsaturated fatty acids implies the plasma membrane undergoes changes in desaturation pattern. The enrichment of endocytosis implies the degradation of plasma membrane and might help the synthesis of new glycerophospholipid with unsaturated fatty acids. Co-enrichments of protein synthesis and degradation imply a higher protein turnover rate. The enrichments of spliceosome and protein processing in endoplasmic reticulum imply the enhancement of regulations at post-transcriptional and post-translational level. No up-regulation of any Na+ or Cl- channels or transporters was detected, which implies that the extra exclusion of the ions by membrane transporters is possibly not needed. Voltage gated Na+ and Cl- channels, mechanosensitive ion channel are possible signal receptors of salt stress, and Ca2+ and MAP kinase pathways might play a role in signal transduction. CONCLUSION: At global transcriptomic level, the response of Dunaliella salina to hypersaline stress is a systematic work, possibly involving enhancements of photosynthesis, carbon fixation, and heme biosynthetic process, acceleration of protein turnover, spliceosome, protein processing in endoplasmic reticulum, and endocytosis, as well as degradation of starch, synthesis of glycerol, membrane lipid desaturation. Altogether, the changes of these biological processes occurred at trancriptomic level will help understand how a new intracellular balance achieved in Dunaliella salina to adapt to hypersaline environment, which are worth being confirmed at the physiological levels.


Assuntos
Clorófitas/genética , Clorófitas/fisiologia , Estresse Salino/fisiologia , Transcriptoma/genética , Cálcio/metabolismo , Clorófitas/metabolismo , Glicerol/metabolismo , Transdução de Sinais/genética , Sódio/metabolismo , Regulação para Cima/genética
12.
Enzyme Microb Technol ; 134: 109487, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32044034

RESUMO

Haematococcus pluvialis could accumulate large amounts of triacylglycerol (TAG) and astaxanthin under various environmental stresses. To gain insights into the multiple defensive systems for carbon metabolism against nitrogen starvation, transcriptome analysis was performed. It was found that the genes related to carbon fixation, glycolysis, fatty acid and carotenoid biosynthesis pathways were up-regulated remarkably. Glyceraldehyde 3-phosphate (G3P) biosynthesis was accelerated with the enhanced C3 and C4 pathway. Meanwhile, the pyruvate kinase (PK) and pyruvate dehydrogenase E2 component (aceF) genes were significantly increased 12.9-fold and 13.9-fold, respectively, resulting more pyruvate and acetyl-CoA generation, which were beneficial to carotenoids and fatty acid biosynthesis. Methylerythritol 4-phosphate (MEP) pathway mediated carotenoid precursor isopentenyl diphosphate (IPP) synthesis, as the all eight related genes were up-regulated. The carbon flux toward astaxanthin biosynthesis with the increased astaxanthin pathway genes. The redistribution of carbon was also promoted for TAG accumulation. In addition, the up-regulation of diacylglycerol acyltransferase (DGAT) and phospholipid: diacylglycerol acyltransferase (PDAT) genes indicated that both acyl-CoA dependent and independent pathway regulated TAG accumulation. Therefore, this work reveals the multiple defensive mechanism for carbon metabolism in response to nitrogen starvation, which extended our understanding on the carotenoids, TAG and other important metabolites synthesis.


Assuntos
Vias Biossintéticas/genética , Clorófitas/genética , Clorófitas/metabolismo , Perfilação da Expressão Gênica , Nitrogênio/metabolismo , Ciclo do Carbono , Carotenoides/metabolismo , Ácidos Graxos/biossíntese , Glicólise , Regulação para Cima
13.
Ecotoxicol Environ Saf ; 190: 110089, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31896472

RESUMO

The use of algae to adsorb heavy metals is an efficient and environmentally friendly treatment for contaminated water and has attracted widespread research attention. In this study, a meta-analysis of the heavy metal adsorption capacity of algae from five different phyla and the factors influencing these capacities was conducted. Phaeophyta was found to have a high heavy metal adsorption capacity, whereas Bacillariophyta had a relatively low adsorption capacity; Chlorophyta, Rhodophyta, and Cyanophyta had moderate adsorption capacities. Non-living algae were more effective in practical applications than living algae were. Algal biomass had a relatively high adsorption efficiency of 1-10 g/L, which did not increase significantly when algal concentration increased. The algal adsorption efficiency for initial heavy metal concentrations of 10-100 mg/L was higher than for concentrations of greater than 100 mg/L. The results further show that algal adsorption of heavy metals reached a maximum capacity of 80-90% within 20 min. Heavy metal adsorption by algae was not temperature-dependent, and it was more effective in moderately to weakly acidic environments (pH = 4-7.5). Considering these aspects for practical applications, algae from some phyla can effectively be used for heavy metal biosorption in contaminated water.


Assuntos
Clorófitas/metabolismo , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Biomassa , Concentração de Íons de Hidrogênio , Feófitas , Rodófitas , Temperatura
14.
BMC Bioinformatics ; 21(1): 1, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31898485

RESUMO

BACKGROUND: The green microalga Dunaliella salina accumulates a high proportion of ß-carotene during abiotic stress conditions. To better understand the intracellular flux distribution leading to carotenoid accumulation, this work aimed at reconstructing a carbon core metabolic network for D. salina CCAP 19/18 based on the recently published nuclear genome and its validation with experimental observations and literature data. RESULTS: The reconstruction resulted in a network model with 221 reactions and 212 metabolites within three compartments: cytosol, chloroplast and mitochondrion. The network was implemented in the MATLAB toolbox CellNetAnalyzer and checked for feasibility. Furthermore, a flux balance analysis was carried out for different light and nutrient uptake rates. The comparison of the experimental knowledge with the model prediction revealed that the results of the stoichiometric network analysis are plausible and in good agreement with the observed behavior. Accordingly, our model provides an excellent tool for investigating the carbon core metabolism of D. salina. CONCLUSIONS: The reconstructed metabolic network of D. salina presented in this work is able to predict the biological behavior under light and nutrient stress and will lead to an improved process understanding for the optimized production of high-value products in microalgae.


Assuntos
Carbono/metabolismo , Clorófitas/metabolismo , Microalgas/metabolismo , Carbono/química , Carotenoides/química , Carotenoides/metabolismo , Clorófitas/química , Clorófitas/efeitos da radiação , Cloroplastos/química , Cloroplastos/metabolismo , Citosol/química , Citosol/metabolismo , Luz , Redes e Vias Metabólicas , Microalgas/química , Microalgas/efeitos da radiação , Mitocôndrias/química , Mitocôndrias/metabolismo , Modelos Biológicos , Estresse Fisiológico
15.
J Biosci Bioeng ; 129(5): 565-572, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31974048

RESUMO

Wastewater treatment, along with the simultaneous production of valuable chemical compounds, including lipids by microalgae is a challenging but attractive study. Towards this goal, the candidate microalgae were selected from culture collections or isolated from wastewater in this study. The initial screening test using microalgae revealed that various eukaryotic as well as prokaryotic microalgae showed steady growth in municipal wastewater samples. Among them, Tetraselmis sp. NKG400013 and Parachlorella kessleri NKG021201 from culture collections, and Chloroidium saccharophilum NKH13 from the wastewater sample exhibited high biomass productivity. Furthermore, P. kessleri NKG021201 and C. saccharophilum NKH13 showed high lipid productivity (56 ± 1 mg/L/day for NKG021201, 35 ± 10 mg/L/day for NKH13). During this cultivation, 99% of nitrogen and 82% of phosphorous compounds were removed from the wastewater sample by the strain NKG021201. Analysis of fatty acid compositions of P. kessleri NKG021201 and C. saccharophilum NKH13 revealed that lipids derived from these microalgae were suitable for the application of biodiesel fuels, indicating that these microalgae were promising for wastewater treatment and lipid production.


Assuntos
Clorófitas/metabolismo , Microalgas/metabolismo , Purificação da Água/métodos , Biodegradação Ambiental , Biocombustíveis/análise , Biomassa , Clorófitas/crescimento & desenvolvimento , Ácidos Graxos/metabolismo , Lipídeos/biossíntese , Microalgas/crescimento & desenvolvimento , Nutrientes/metabolismo , Águas Residuárias/química
16.
J Biosci Bioeng ; 129(6): 687-692, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31937470

RESUMO

Production of biofuels and fine chemicals from biomass-derived carbohydrates through biorefinery attracts much attention because it is recognized as an environmentally friendly process. Microalgae can serve as promising carbohydrate producers for biorefinery rather than woody and crop biomass due to high biomass productivity, high CO2 fixation, and no competition with food production. However, microalgae with high carbohydrate productivity have not been well investigated despite intensive studies of microalgal lipid production. In this study, the carbohydrate production of Pseudoneochloris sp. strain NKY372003 isolated as a high carbohydrate producer, was investigated. Cultivation conditions with various combinations of nutrient contents and photon flux density were examined to maximize the biomass and carbohydrate productivities. At the optimal condition, the biomass and carbohydrate production of this strain reached 8.11 ± 0.37 g/L and 5.5 ± 0.2 g/L, respectively. As far as we know, this is the highest carbohydrate production by microalgae among ever reported. Cell staining with Lugol's solution visualized intracellular starch granules. Because algal starch can be converted to biofuels and building blocks of fine chemicals, Pseudoneochloris sp. NKY372003 will be a promising candidate for production of fermentable carbohydrates towards biofuels and fine chemicals production.


Assuntos
Clorófitas/metabolismo , Biocombustíveis , Biomassa , Metabolismo dos Carboidratos , Carboidratos/química , Lipídeos/biossíntese , Microalgas/química
17.
J Biosci Bioeng ; 129(1): 86-92, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31302007

RESUMO

The unicellular green microalga Haematococcus pluvialis accumulates large amounts of the red ketocarotenoid astaxanthin. Aiming to cultivate these microalgae with high astaxanthin efficiency, cultivations were scaled-up from 1000 mL bottle to 2 L and 8 L airlift photobioreactor using volumetric power consumption rate (W/m3) as scale up strategy. After cultivations, computational fluid dynamics (CFD) simulation was used to investigate the flow patterns, mixing efficiency and gas holdup profile within the 2 L photobioreactor. At the end, astaxanthin content was enhanced with increasing the cultivation volume and highest astaxanthin amount of 49.39 ± 1.64 mg/g cell was obtained in 8 L photobioreactor. Hydrodynamic characteristics of photobioreactor was simulated and gas holdup showed difference between the riser and the downcomer regions. Velocity profiles of air and medium had higher values inside the draft tube than obtained in downcomer region. However liquid circulation was achieved from draft tube to the downcomer, mixing was not provided effectively considering the turbulence kinetic energy. For the further research, some developments about column configuration, sparger diameter may be necessary to enhance the mixing characteristics.


Assuntos
Clorófitas/metabolismo , Microalgas/metabolismo , Fotobiorreatores , Clorófitas/química , Clorófitas/crescimento & desenvolvimento , Clorófitas/efeitos da radiação , Hidrodinâmica , Cinética , Luz , Microalgas/química , Microalgas/crescimento & desenvolvimento , Microalgas/efeitos da radiação , Xantofilas/química , Xantofilas/metabolismo
18.
Prep Biochem Biotechnol ; 50(1): 98-105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31809237

RESUMO

Nitrogen, being one of the building blocks of biomacromolecules, is an important nutrient for microalgae growth. Nitrogen availability alters the growth and biochemical composition of microalgae. We investigated the effects of different nitrogen concentrations on specific growth rate (SGR), biomass productivity (BP), total protein and lipid content and amino acid and fatty acid composition of Desmodesmus communis. Nitrogen deficiency increased algal growth and changed the lipid amount and composition. The maximum growth and BP were detected in 75% N-medium. The highest total protein and lipid amount were detected in 50% N- and 75% N-media, respectively. Amino acid and fatty acid compositions of samples varied widely depending on the nutrient concentrations. The amount of unsaturated fatty acid (USFAs) was higher than saturated fatty acid (SFAs) and Linolenic acid percentage is higher than the limit of European standards in all media. The data reported here provide important contributions how nitrogen scarcity and abundance affect the growth and biochemical content of microalgae and this information can further be utilized in culture optimization in studies aimed at microalgae production for biofuels.


Assuntos
Biomassa , Clorófitas/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Nitrogênio/metabolismo , Aminoácidos/análise , Aminoácidos/metabolismo , Clorófitas/metabolismo , Meios de Cultura/análise , Meios de Cultura/metabolismo , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Metabolismo dos Lipídeos , Lipídeos/análise , Microalgas/metabolismo , Nitrogênio/análise , Proteínas de Plantas/análise , Proteínas de Plantas/metabolismo
19.
Biochim Biophys Acta Bioenerg ; 1861(2): 148139, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31825812

RESUMO

An aerial green alga, Prasiola crispa (Lightf.) Menegh, which is known to form large colonies in Antarctic habitats, is subject to severe environmental stresses due to low temperature, draught and strong sunlight in summer. A considerable light-absorption by long-wavelength chlorophylls (LWC) at around 710 nm, which seem to consist of chlorophyll a, was detected in thallus of P. crispa harvested at a terrestrial environment in Antarctica. Absorption level at 710 nm against that at 680 nm was correlated with fluorescence emission intensity at 713 nm at room temperature and the 77 K fluorescence emission band from LWC was found to be emitted at 735 nm. We demonstrated that the LWC efficiently transfer excitation energy to photosystem II (PSII) reaction center from measurements of action spectra of photosynthetic oxygen evolution and P700 photo-oxidation. The global quantum yield of PSII excitation in thallus by far-red light was shown to be as high as by orange light, and the excitation balance between PSII and PSI was almost same in the two light sources. It is thus proposed that the LWC increase the photosynthetic productivity in the lower parts of overlapping thalli and contribute to the predominance of alga in the severe environment.


Assuntos
Clorofila A/metabolismo , Clorófitas/metabolismo , Luz , Complexo de Proteína do Fotossistema II/metabolismo , Regiões Antárticas , Complexos de Proteínas Captadores de Luz/metabolismo , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Espectrometria de Fluorescência
20.
Ecotoxicol Environ Saf ; 189: 109995, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31785947

RESUMO

The use of p-chloroaniline (PCA) in various aspects leads to its existence and accumulation in the environment. Relevant researches showed that PCA was a prime toxic pollutant that had imposed a serious risk to public health and the environment. This paper investigated the toxicity effects of PCA on Platymonas subcordiformis (P. subcordiformis) and the biodegradation of PCA by the marine microalga. In the toxicity experiments, the EC50 of PCA on P. subcordiformis at 24 h, 48 h, 72 h and 96 h was 41.42, 24.04, 17.15 and 13.05 mg L-1, respectively. The pigment parameters including chlorophyll a, chlorophyll b, carotenoids, photosynthetic O2 release rate, respiration O2 consumption rate and the chlorophyll fluorescence parameters including Fv/Fm, ETR and qP decreased greatly while antioxidant enzyme activities (SOD, CAT) and the chlorophyll fluorescence parameter NPQ increased when P. subcordiformis exposed to PCA compared with the control group. Fv/Fm would be a suitable indicator for assessing the toxicity of PCA in marine environment based on the analysis of Pearson's correlation coefficient and Integrated Biomarker Response (IBR). The degradation assay in P. subcordiformis indicated that the green marine microalga had the ability to remove and degrade PCA, and the order of removal and degradation proportion of PCA was 2 mg L-1 > 5 mg L-1>10 mg L-1. The maximum removal and biodegradation percentage was 54% and 34%, respectively.


Assuntos
Compostos de Anilina/toxicidade , Clorófitas/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Compostos de Anilina/metabolismo , Biodegradação Ambiental , Carotenoides/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Clorófitas/metabolismo , Oxigênio/metabolismo , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA