Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 345
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Biochim Biophys Acta Bioenerg ; 1860(6): 488-498, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31029593

RESUMO

The phycobilisome, the cyanobacterial light harvesting complex, is a huge phycobiliprotein containing extramembrane complex, formed by a core from which rods radiate. The phycobilisome has evolved to efficiently absorb sun energy and transfer it to the photosystems via the last energy acceptors of the phycobilisome, ApcD and ApcE. ApcF also affects energy transfer by interacting with ApcE. In this work we studied the role of ApcD and ApcF in energy transfer and state transitions in Synechococcus elongatus and Synechocystis PCC6803. Our results demonstrate that these proteins have different roles in both processes in the two strains. The lack of ApcD and ApcF inhibits state transitions in Synechocystis but not in S. elongatus. In addition, lack of ApcF decreases energy transfer to both photosystems only in Synechocystis, while the lack of ApcD alters energy transfer to photosystem I only in S. elongatus. Thus, conclusions based on results obtained in one cyanobacterial strain cannot be systematically transferred to other strains and the putative role(s) of phycobilisomes in state transitions need to be reconsidered.


Assuntos
Proteínas de Bactérias/metabolismo , Ficobilissomas/metabolismo , Ficocianina/metabolismo , Synechococcus/metabolismo , Proteínas de Bactérias/genética , Transferência de Energia/fisiologia , Mutação , Complexo de Proteína do Fotossistema I/metabolismo , Espectrometria de Fluorescência , Espectrometria de Massas em Tandem
2.
Bioresour Technol ; 284: 340-348, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30954902

RESUMO

The objective was to evaluate the effect of reusing Zarrouk's medium on a Spirulina sp. LEB 18 culture by determining kinetic parameters, chemical composition, biofuels, and thermal characterization. Cultivation was performed in a raceway bioreactor for 7 days, the supernatant was reused for four cycles. Culturing the microalga in the reused medium resulted in a cellular yield of 2.30 g L-1 (control) and 2.04, 1.89, 1.73, and 1.15 g L-1 for four cycles with no influence on cell growth and productivity. Biomass with high contents of carbohydrates (58.00%, 3rd cycle), phycocyanin (2.47 mg mL-1, 1st cycle), and saturated fatty acids (60.13%, 4th cycle) were obtained with an increase in the profiles of C16:0 (45.85%) and C18:2n6 (47.40%) in the 1st cycle. The reuse of Zarrouk's medium allowed obtaining biomass with reduced cost and differentiated characteristics, allowing the exploration of commercially important biomolecules by the completion of up to four cycles.


Assuntos
Reatores Biológicos , Spirulina/metabolismo , Biocombustíveis , Biomassa , Metabolismo dos Carboidratos , Carboidratos , Ficocianina/metabolismo
3.
Mol Plant ; 12(5): 715-725, 2019 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-30818037

RESUMO

Cyanobacteria have evolved various photoacclimation processes to perform oxygenic photosynthesis under different light environments. Chromatic acclimation (CA) is a widely recognized and ecologically important type of photoacclimation, whereby cyanobacteria alter the absorbing light colors of a supermolecular antenna complex called the phycobilisome. To date, several CA variants that regulate the green-absorbing phycoerythrin (PE) and/or the red-absorbing phycocyanin (PC) within the hemi-discoidal form of phycobilisome have been characterized. In this study, we identified a unique CA regulatory gene cluster encoding yellow-green-absorbing phycoerythrocyanin (PEC) and a rod-membrane linker protein (CpcL) for the rod-shaped form of phycobilisome. Using the cyanobacterium Leptolyngbya sp. PCC 6406, we revealed novel CA variants regulating PEC (CA7) and the rod-shaped phycobilisome (CA0), which maximize yellow-green light-harvesting capacity and balance the excitation of photosystems, respectively. Analysis of the distribution of CA gene clusters in 445 cyanobacteria genomes revealed eight CA variants responding to green and red light, which are classified based on the presence of PEC, PE, cpcL, and CA photosensor genes. Phylogenetic analysis further suggested that the emergence of CA7 was a single event and preceded that of heterocystous strains, whereas the acquisition of CA0 occurred multiple times. Taken together, these results offer novel insights into the diversity and evolution of the complex cyanobacterial photoacclimation mechanisms.


Assuntos
Aclimatação/efeitos da radiação , Cianobactérias/fisiologia , Cianobactérias/efeitos da radiação , Luz , Ficobilinas/metabolismo , Ficobilissomas/metabolismo , Ficocianina/metabolismo , Cor , Cianobactérias/genética , Cianobactérias/metabolismo , Evolução Molecular , Família Multigênica/genética , Mutação
4.
Biochim Biophys Acta Bioenerg ; 1860(4): 286-296, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30703363

RESUMO

In this study, we use ultrafast time-resolved absorption and fluorescence spectroscopies to examine A. marina phycobilisomes isolated from cells grown under light of different intensities and spectral regimes. Investigations were performed at room temperature and at 77 K. The study demonstrates that if complexes are stabilized by high phosphate (900 mM) buffer, there are no differences between them in temporal and spectral properties of fluorescence. However, when the complexes are allowed to disassemble into trimers in low phosphate (50 mM) buffer, differences are clearly observed. The fluorescence properties of intact or disassembled phycobilisomes from cells grown in low intensity white light are unresponsive to variation in phosphate concentration. This antenna complex was further studied in detail with application of femtosecond time-resolved absorption at room temperature. Combined spectroscopic and kinetic analysis of time-resolved fluorescence and absorption data of this antenna allowed us to identify spectrally different forms of phycocyanobilins and to propose a simplified model of how they could be distributed within the phycobilisome structure.


Assuntos
Proteínas de Bactérias/metabolismo , Cianobactérias/enzimologia , Ficobilinas/metabolismo , Ficobilissomas/metabolismo , Ficocianina/metabolismo , Proteínas de Bactérias/química , Ficobilinas/química , Ficobilissomas/química , Ficocianina/química , Espectrometria de Fluorescência
5.
Biochim Biophys Acta Mol Cell Res ; 1866(2): 277-284, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30471307

RESUMO

Biliproteins have extended the spectral range of fluorescent proteins into the near-infrared region (NIR, 700-770 nm) of maximal transmission of most tissues and are also favorable for multiplex labeling. Their application, however, presents considerable challenges to increase their stability under physiological conditions and, in particular, to increase their brightness while maintaining the emission in near-infrared regions: their fluorescence yield generally decreases with increasing wavelengths, and their effective brightness depends strongly on the environmental conditions. We report a fluorescent biliprotein triad, termed BDFP1.1:3.1:1.1, that combines a large red-shift (722 nm) with high brightness in mammalian cells and high stability under changing environmental conditions. It is fused from derivatives of the phycobilisome core subunits, ApcE2 and ApcF2. These two subunits are induced by far-red light (FR, 650-700 nm) in FR acclimated cyanobacteria. Two BDFP1.1 domains engineered from ApcF2 covalently bind biliverdin that is accessible in most cells. The soluble BDFP3 domain, engineered from ApcE2, binds phytochromobilin non-covalently, generating BDFP3.1. This phytochromobilin chromophore was added externally; it is readily generated by an improved synthesis in E. coli and subsequent extraction. Excitation energy absorbed in the FR by covalently bound biliverdins in the two BDFP1.1 domains is transferred via fluorescence resonance energy transfer to the non-covalently bound phytochromobilin in the BDFP3.1 domain fluorescing in the NIR around 720 nm. Labeling of a variety of proteins by fusion to the biliprotein triad is demonstrated in prokaryotic and mammalian cells, including human cell lines.


Assuntos
Bilirrubina/química , Corantes Fluorescentes/química , Imagem Óptica/métodos , Animais , Proteínas de Bactérias/metabolismo , Bilirrubina/metabolismo , Biliverdina/química , Biliverdina/metabolismo , Cianobactérias/metabolismo , Escherichia coli/metabolismo , Fluorescência , Transferência Ressonante de Energia de Fluorescência/métodos , Corantes Fluorescentes/metabolismo , Humanos , Luz , Microscopia de Fluorescência , Ficobilissomas/metabolismo , Ficocianina/química , Ficocianina/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/métodos
6.
J Biosci Bioeng ; 126(6): 778-782, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30401453

RESUMO

Fusion protein of streptavidin and allophycocyanin holo-α subunit (ApcA) is fluorescent and is able to bind biotin. This fusion protein (SLA) can be used as fluorescent label in immunofluorescence assay. In this study, one or two repeats of ApcA were fused to the protein SLA, with the aim to improve its brightness. The fusion proteins SLA2 (two repeats of ApcA) and SLA3 (three repeats of ApcA), together with lyase (cpcS) and phycoerythrobilin synthesizing enzymes (Ho1 and PebS), were co-expressed in Escherichia coli. These fusion proteins were purified by affinity chromatography. While SLA2 and SLA3 shared similar absorbance spectra, fluorescence spectra and biotin-binding activities with SLA, their brightness were much higher than that of SLA. When used as fluorescent labels in immunofluorescence assay, SLA2 and SLA3 showed higher detection sensitivity than SLA. These results suggested that SLA2 and SLA3 were the preferable fluorescent labels in immunofluorescence assays.


Assuntos
Escherichia coli/metabolismo , Imunofluorescência/métodos , Corantes Fluorescentes/metabolismo , Ficocianina/metabolismo , Proteínas Recombinantes de Fusão/biossíntese , Cromatografia de Afinidade/métodos , Escherichia coli/genética , Corantes Fluorescentes/química , Liases/genética , Liases/metabolismo , Ficobilinas/química , Ficobilinas/metabolismo , Ficocianina/química , Ficoeritrina/química , Ficoeritrina/metabolismo , Subunidades Proteicas , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Estreptavidina/química , Estreptavidina/metabolismo
7.
Bioresour Technol ; 270: 320-327, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30241065

RESUMO

An aqueous two-phase system (ATPS) with ionic liquids (ILs) was used for the isolate of C-phycocyanin (CPC) from Spirulina platensis microalga. Various imidazolium ILs and potassium salts were studied. The effect of ILs-ATPS on the extraction efficiency of CPC was also studied. The experimental parameters like pH, loading volume, algae concentration, temperature, and alkyl chain length of IL were well-covered in this report. The experimental results showed that the extraction efficiency, the partition coefficient, and the separation factor for CPC were 99%, 36.6, and 5.8, respectively, for an optimal pH value of 7 and a temperature of 308 K. The order of extraction efficiency for CPC using IL-ATPS was: 1-octyl-3-methylimidazolium bromide (C8MIM-Br) > 1-hexyl-3-methylimidazolium bromide (C6MIM-Br) > 1-butyl-3-methylimidazolium bromide (C4MIM-Br). The isolation process followed the pseudo second-order kinetic model and the thermodynamic results were obviously spontaneous.


Assuntos
Microalgas/metabolismo , Ficocianina/metabolismo , Spirulina/metabolismo , Boratos/química , Imidazóis/química , Líquidos Iônicos/química , Microalgas/química , Ficocianina/química , Spirulina/química , Temperatura Ambiente , Termodinâmica
8.
J Biol Chem ; 293(46): 17705-17715, 2018 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-30242127

RESUMO

Cyanobacteriochromes (CBCRs) are photochromic proteins in cyanobacteria that act as photosensors. CBCRs bind bilins as chromophores and sense nearly the entire visible spectrum of light, but the regulation of the chromophorylation of CBCRs is unknown. Slr1393 from Synechocystis sp. PCC 6803 is a CBCR containing three consecutive GAF (cGMP phosphodiesterase, adenylyl cyclase, and FhlA protein) domains, of which only the third one (Slr1393g3) can be phycocyanobilin-chromophorylated. The protein Slr2111 from Synechocystis sp. PCC 6803 includes a cystathionine ß-synthase (CBS) domain pair of an as yet unknown function at its N terminus. CBS domains are often characterized as sensors of cellular energy status by binding nucleotides. In this work, we demonstrate that Slr2111 strongly interacts with Slr1393 in vivo and in vitro, which generates a complex in a 1:1 molar ratio. This tight interaction inhibits the chromophorylation of Slr1393g3, even if the chromophore is present. Instead, the complex stability and thereby the chromophorylation of Slr1393 are regulated by the binding of nucleotides (ATP, ADP, AMP) to the CBS domains of Slr2111 with varying affinities. It is demonstrated that residues Asp-53 and Arg-97 of Slr2111 are involved in nucleotide binding. While ATP binds to Slr2111, the association between the two proteins gets weaker and chromophorylation of Slr1393 are enabled. In contrast, AMP binding to Slr2111 leads to a stronger association, thereby inhibiting the chromophorylation. It is concluded that Slr2111 acts as a sensor of the cellular energy status that regulates the chromophorylation of Slr1393 and thereby its function as a light-driven histidine kinase.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Fotorreceptores Microbianos/metabolismo , Ficobilinas/metabolismo , Ficocianina/metabolismo , Difosfato de Adenosina/metabolismo , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Transporte/química , Proteínas de Transporte/genética , Histidina Quinase/metabolismo , Cinética , Simulação de Acoplamento Molecular , Mutação , Ligação Proteica , Conformação Proteica , Alinhamento de Sequência , Synechocystis/química
9.
J Agric Food Chem ; 66(41): 10921-10929, 2018 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-30253646

RESUMO

As a type of functional food additive, phycocyanin is shown to have a potential antineoplastic property. However, its underlying anticancer mechanism in melanoma cells remains unknown. We previously reported a 35S in vivo/vitro labeling analysis for dynamic proteomic (SiLAD) technology. It could exclusively detect protein synthesis rates via pulse labeling of newly expressed proteins by 35S, providing a high time-resolution method for analysis of protein variations. In the present study, we performed a time course analysis in A375 melanoma cells after phycocyanin treatment using SiLAD. Protein expression velocities were specifically visualized and their regulation modes were dynamically traced. Strikingly, novel protein synthesis patterns were discovered in the early phase of phycocyanin treatment, suggesting a possible mechanism of phycocyanin regulation. Furthermore, network analysis and phenotype experiments demonstrated that GRB2-ERK1/2 pathway was involved in phycocyanin-mediated regulation process and responsible for the proliferation suppression of melanoma cell, which could be a therapeutic target for malignant melanoma.


Assuntos
Antineoplásicos/química , Aditivos Alimentares/química , Melanoma/tratamento farmacológico , Ficocianina/química , Neoplasias Cutâneas/tratamento farmacológico , Antineoplásicos/metabolismo , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Aditivos Alimentares/metabolismo , Aditivos Alimentares/uso terapêutico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Cinética , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Ficocianina/metabolismo , Ficocianina/uso terapêutico , Proteínas/metabolismo , Proteômica/métodos
10.
J Proteome Res ; 17(11): 3628-3643, 2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30216071

RESUMO

The unicellular cyanobacterium Cyanothece ATCC 51142 is capable of oxygenic photosynthesis and biological N2 fixation (BNF), a process highly sensitive to oxygen. Previous work has focused on determining protein expression levels under different growth conditions. A major gap of our knowledge is an understanding on how these expressed proteins are assembled into complexes and organized into metabolic pathways, an area that has not been thoroughly investigated. Here, we combined size-exclusion chromatography (SEC) with label-free quantitative mass spectrometry (MS) and bioinformatics to characterize many protein complexes from Cyanothece 51142 cells grown under a 12 h light-dark cycle. We identified 1386 proteins in duplicate biological replicates, and 64% of those proteins were identified as putative complexes. Pairwise computational prediction of protein-protein interaction (PPI) identified 74 822 putative interactions, of which 2337 interactions were highly correlated with published protein coexpressions. Many sequential glycolytic and TCA cycle enzymes were identified as putative complexes. We also identified many membrane complexes that contain cytoplasmic domains. Subunits of NDH-1 complex eluted in a fraction with an approximate mass of ∼669 kDa, and subunits composition revealed coexistence of distinct forms of NDH-1 complex subunits responsible for respiration, electron flow, and CO2 uptake. The complex form of the phycocyanin beta subunit was nonphosphorylated, and the monomer form was phosphorylated at Ser20, suggesting phosphorylation-dependent deoligomerization of the phycocyanin beta subunit. This study provides an analytical platform for future studies to reveal how these complexes assemble and disassemble as a function of diurnal and circadian rhythms.


Assuntos
Proteínas de Bactérias/química , Cyanothece/química , Complexos Multiproteicos/química , Ficocianina/metabolismo , Processamento de Proteína Pós-Traducional , Proteoma/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Dióxido de Carbono/metabolismo , Cromatografia em Gel , Ciclo do Ácido Cítrico/fisiologia , Biologia Computacional , Cyanothece/metabolismo , Glicólise/fisiologia , Espectrometria de Massas , Complexos Multiproteicos/metabolismo , Nitrogênio/metabolismo , Fixação de Nitrogênio/fisiologia , Oxigênio/metabolismo , Fosforilação , Fotossíntese/fisiologia , Ficocianina/química , Mapeamento de Interação de Proteínas , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Proteoma/isolamento & purificação , Proteoma/metabolismo , Proteômica/métodos
11.
Bioresour Technol ; 247: 669-675, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30060398

RESUMO

C-phycocyanin (C-PC) produced from Spirulina platensis is of great commercial interest due to its healthcare properties. In this study, light sources and light-dark frequency were manipulated to enhance C-PC productivity of S. platensis. Using white LED resulted in higher C-PC production efficiency when compared to using fluorescent lamps and monochromatic LEDs. Proper adjustment of light-dark efficiency further increased C-PC production efficiency with relatively lower power consumption. In addition, using recycled medium in place of fresh medium proved to be an environmental-friendly and economic strategy for C-PC production with S. platensis. Optimal nitrate supplementation was also employed to improve the C-PC productivity. When grown under optimal culture conditions (i.e., light source, white LED; light-dark frequency, 30:30; recycled medium replacement, 50%; nitrate supplement, 45mM), S. platensis could obtain the highest C-PC content (14.9%) and C-PC productivity (101.1mg/L/d). This performance appears to be superior to that obtained from most related studies.


Assuntos
Ficocianina/metabolismo , Spirulina , Reatores Biológicos/economia , Nitratos
12.
Biomed Pharmacother ; 106: 532-542, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29990841

RESUMO

The phenotype of multidrug resistance (MDR) is one of the main causes of chemotherapy failure. Our study investigated the effect of C-phycocyanin (C-PC) in three human erythroleukemia cell lines with or without the MDR phenotype: K562 (non-MDR; no overexpression of drug efflux proteins), K562-Lucena (MDR; overexpression of ATP-binding cassette, sub-family B/ABCB1), and FEPS (MDR; overexpression of ABCB1 and ATP-binding cassette, sub-family C/ABCC1). Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, we showed that 20 and 200 µg/mL C-PC decreased K562 viable cells after 24 h and 200 µg/mL C-PC decreased K562-Lucena cell proliferation after 48 h. C-PC did not decrease viable cells of FEPS cells. On the other hand, the MTT assay showed that exposure of 2, 20, and 200 µg/mL C-PC for 24 or 48 h was not cytotoxic to peritoneal macrophages. At 72 h, the trypan blue exclusion assay showed that 20 µg/mL C-PC decreased K562 and K562-Lucena cell proliferation and in FEPS cells, only 200 µg/mL C-PC decreased proliferation. In addition, protein-protein docking showed differences in energy and binding sites of ABCB1 and ABCC1 for C-PC, and these results were confirmed by the efflux protein activity assay. Only ABCC1 activity was altered in the presence of C-PC and FEPS cells showed lower C-PC accumulation, suggesting C-PC extrusion by ABCC1, conferring C-PC resistance. In combination with chemotherapy (vincristine [VCR] and daunorubicin [DNR]), the sensitivity of K562-Lucena cells for C-PC + VCR did not increase, whereas FEPS cell sensitivity for C-PC + DNR was increased. In molecular docking experiments, the estimated free energies of binding for C-PC associated with chemotherapy were similar (VCR: -6.9 kcal/mol and DNR: -7.2 kcal/mol) and these drugs were located within the C-PC cavity. However, C-PC exhibited specificity for tumor cells and K562 cells were more sensitive than K562-Lucena cells, followed by FEPS cells. Thus, C-PC is a possible chemotherapeutic agent for cells with the MDR phenotype, both alone in K562-Lucena cells (resistance due to ABCB1), or in combination with other drugs for cells similar to FEPS (resistance due to ABCC1). Moreover, C-PC did not damage healthy cells (peritoneal macrophages of Mus musculus).


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Daunorrubicina/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Leucemia Eritroblástica Aguda/tratamento farmacológico , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Ficocianina/farmacologia , Vincristina/farmacologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/toxicidade , Sítios de Ligação , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Resistência a Múltiplos Medicamentos/genética , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Células K562 , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/metabolismo , Leucemia Eritroblástica Aguda/patologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/patologia , Camundongos , Simulação de Acoplamento Molecular , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Ficocianina/metabolismo , Ficocianina/toxicidade , Ligação Proteica , Conformação Proteica , Fatores de Tempo
13.
Photosynth Res ; 138(2): 177-189, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30027501

RESUMO

Several studies have described that cyanobacteria use blue light less efficiently for photosynthesis than most eukaryotic phototrophs, but comprehensive studies of this phenomenon are lacking. Here, we study the effect of blue (450 nm), orange (625 nm), and red (660 nm) light on growth of the model cyanobacterium Synechocystis sp. PCC 6803, the green alga Chlorella sorokiniana and other cyanobacteria containing phycocyanin or phycoerythrin. Our results demonstrate that specific growth rates of the cyanobacteria were similar in orange and red light, but much lower in blue light. Conversely, specific growth rates of the green alga C. sorokiniana were similar in blue and red light, but lower in orange light. Oxygen production rates of Synechocystis sp. PCC 6803 were five-fold lower in blue than in orange and red light at low light intensities but approached the same saturation level in all three colors at high light intensities. Measurements of 77 K fluorescence emission demonstrated a lower ratio of photosystem I to photosystem II (PSI:PSII ratio) and relatively more phycobilisomes associated with PSII (state 1) in blue light than in orange and red light. These results support the hypothesis that blue light, which is not absorbed by phycobilisomes, creates an imbalance between the two photosystems of cyanobacteria with an energy excess at PSI and a deficiency at the PSII-side of the photosynthetic electron transfer chain. Our results help to explain why phycobilisome-containing cyanobacteria use blue light less efficiently than species with chlorophyll-based light-harvesting antennae such as Prochlorococcus, green algae and terrestrial plants.


Assuntos
Chlorella/efeitos da radiação , Luz , Fotossíntese/efeitos da radiação , Complexo de Proteína do Fotossistema I/efeitos da radiação , Complexo de Proteína do Fotossistema II/efeitos da radiação , Synechocystis/efeitos da radiação , Chlorella/fisiologia , Oxigênio/metabolismo , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema I/fisiologia , Complexo de Proteína do Fotossistema II/fisiologia , Ficocianina/metabolismo , Ficoeritrina/metabolismo , Pigmentos Biológicos/metabolismo , Synechocystis/fisiologia
14.
J Agric Food Chem ; 66(32): 8522-8529, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30016092

RESUMO

This study aimed to improve the production of phycobiliproteins using TiO2 nanoparticles (NPs) in Synechocystis sp. PCC 6803. The growth characteristics of Synechocystis cells were not affected by TiO2 NPs treatment, but this treatment increased the chlorophyll content significantly by 62.2% (14.6 mg/L) compared to that of control (9.0 mg/L) on day 16. Phycocyanin production was increased by 33.8% (29.3 g/L) compared to that of control (21.9 g/L) on day 8. Allophycocyanin production was increased by 55.0% (6.2 g/L) compared to that of control (4.0 g/L) on day 8, and by 22.4% (16.4 g/L) compared to that of control (13.4 g/L) on day 16. Direct infusion mass spectrometry revealed that TiO2 NPs treatment significantly increased the levels of major thylakoid membranes of monogalactosyldiacylglycerols (18:2/18:3, 18:2/18:2, 18:1/18:2), phosphatidylglycerol (16:0/16:1), and sulfoquinovosyldiacylglycerols (16:0/16:1, 16:0:18:4) on day 8. These findings indicate that TiO2 NPs have potential for commercial applications in Synechocystis species or other microalgal strains.


Assuntos
Lipídeos/química , Ficobiliproteínas/metabolismo , Synechocystis/efeitos dos fármacos , Synechocystis/metabolismo , Titânio/farmacologia , Clorofila/química , Clorofila/metabolismo , Metabolismo dos Lipídeos , Espectrometria de Massas , Microalgas/química , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Nanopartículas/análise , Ficocianina/química , Ficocianina/metabolismo , Synechocystis/química , Synechocystis/crescimento & desenvolvimento
15.
Photosynth Res ; 138(1): 39-56, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29943359

RESUMO

Synechococcus ATCC 29403 (PCC 7335) is a unicellular cyanobacterium isolated from Puerto Peñasco, Sonora Mexico. This cyanobacterium performs complementary chromatic acclimation (CCA), far-red light photoacclimation (FaRLiP), and nitrogen fixation. The Synechococcus PCC 7335 genome contains at least 31 genes for proteins of the phycobilisome (PBS). Nine constitutive genes were expressed when cells were grown under white or red lights and the resulting proteins were identified by mass spectrometry in isolated PBS. Five inducible genes were expressed under white light, and phycoerythrin subunits and associated linker proteins were detected. The proteins of five inducible genes expressed under red light were identified, the induced phycocyanin subunits, two rod linkers and the rod-capping linker. The five genes for FaRLiP phycobilisomes were expressed under far-red light together with the apcF gene, and the proteins were identified by mass spectrometry after isoelectric focusing and SDS-PAGE. Based on in silico analysis, Phylogenetic trees, and the observation of a highly conserved amino acid sequence in far-red light absorbing alpha allophycoproteins encoded by FaRLiP gene cluster, we propose a new nomenclature for the genes. Based on a ratio of ApcG2/ApcG3 of six, a model with the arrangement of the allophycocyanin trimers of the core is proposed.


Assuntos
Proteínas de Bactérias/genética , Ficobilissomas/metabolismo , Synechococcus/fisiologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Simulação por Computador , Eletroforese em Gel de Poliacrilamida/métodos , Genoma Bacteriano , Luz , Espectrometria de Massas , Modelos Biológicos , Ficobilinas/metabolismo , Ficobilissomas/genética , Ficocianina/genética , Ficocianina/metabolismo , Ficoeritrina/genética , Ficoeritrina/metabolismo , Proteômica/métodos , Synechococcus/metabolismo , Zinco/química
16.
Curr Pharm Des ; 24(17): 1859-1864, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29766794

RESUMO

The time window for neuroprotection during ischemic brain stroke is short, and hence, development of neuroprotectants is critical to extend this time window. This study sought to verify if muco-adhesive chitosan coating improves the neuroprotective potential of the pre-proven C-Phycocyanin-pertaining liposome (C-Pc liposome). The use of chitosan-coated liposomes extended the neuroprotective time window by 6 h after occlusion, and further improved the neuroprotection efficiency of the C-Pc liposome in a rat Middle Cerebral Artery Occlusion (MCAO) model. Beneficial changes in mRNA expressions of antioxidants, inflammatory cytokines and glia scar proteoglycans were evident in the C-Pc liposomes. In addition, in the cultured astrocytes, the chitosan- coated C-Pc liposome expressed anti-oxidative activity without cytotoxicity.


Assuntos
Quitosana/uso terapêutico , Infarto da Artéria Cerebral Média/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Ficocianina/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Animais , Quitosana/química , Quitosana/metabolismo , Modelos Animais de Doenças , Lipossomos/química , Lipossomos/metabolismo , Lipossomos/uso terapêutico , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/metabolismo , Ficocianina/química , Ficocianina/metabolismo , Ratos
17.
Water Res ; 141: 152-162, 2018 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-29783168

RESUMO

In recent years, there has been a widespread deployment of submersible fluorescence sensors by water utilities. They are used to measure diagnostic pigments and estimate algae and cyanobacteria abundance in near real-time. Despite being useful and promising tools, operators and decision-makers often rely on the data provided by these probes without a full understanding of their limitations. As a result, this may lead to wrong and misleading estimations which, in turn, means that researchers and technicians distrust these sensors. In this review paper, we list and discuss the main limitations of such probes, as well as identifying the effect of environmental factors on pigment production, and in turn, the conversion to cyanobacteria abundance estimation. We argue that a comprehensive calibration approach to obtain reliable readings goes well beyond manufacturers' recommendations, and should involve several context-specific experiments. We also believe that if such a comprehensive set of experiments is conducted, the data collected from fluorescence sensors could be used in artificial intelligence modelling approaches to reliably predict, in near real-time, the presence and abundance of different cyanobacteria species. This would have significant benefits for both drinking and recreational water management, given that cyanobacterial toxicity, and taste and odour compounds production, are species-dependent.


Assuntos
Cianobactérias , Monitoramento Ambiental/métodos , Corantes Fluorescentes , Clorofila/metabolismo , Clorofila A , Cianobactérias/metabolismo , Fluorescência , Odorantes , Ficocianina/metabolismo , Medição de Risco , Paladar , Poluentes da Água/toxicidade
18.
Nat Commun ; 9(1): 1931, 2018 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-29789561

RESUMO

The synthetic yeast genome constructed by the International Synthetic Yeast Sc2.0 consortium adds thousands of loxPsym recombination sites to all 16 redesigned chromosomes, allowing the shuffling of Sc2.0 chromosome parts by the Cre-loxP recombination system thereby enabling genome evolution experiments. Here, we present L-SCRaMbLE, a light-controlled Cre recombinase for use in the yeast Saccharomyces cerevisiae. L-SCRaMbLE allows tight regulation of recombinase activity with up to 179-fold induction upon exposure to red light. The extent of recombination depends on induction time and concentration of the chromophore phycocyanobilin (PCB), which can be easily adjusted. The tool presented here provides improved recombination control over the previously reported estradiol-dependent SCRaMbLE induction system, mediating a larger variety of possible recombination events in SCRaMbLE-ing a reporter plasmid. Thereby, L-SCRaMbLE boosts the potential for further customization and provides a facile application for use in the S. cerevisiae genome re-engineering project Sc2.0 or in other recombination-based systems.


Assuntos
Edição de Genes/métodos , Genoma Fúngico , Integrases/genética , Ficobilinas/metabolismo , Ficocianina/metabolismo , Recombinação Genética/efeitos da radiação , Saccharomyces cerevisiae/genética , Células Clonais , Expressão Gênica , Genes Sintéticos , Engenharia Genética/métodos , Integrases/metabolismo , Luz , Plasmídeos/química , Plasmídeos/metabolismo , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efeitos da radiação , Seleção Genética
19.
Microbiol Res ; 211: 47-56, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29705205

RESUMO

A novel halotolerant species of cyanobacterium of the order Chroococcales was isolated from hypersaline estuary in Kwa-Zulu Natal, South Africa. A comprehensive polyphasic approach viz., cell morphology, pigment composition and complete genome sequence analysis was conducted to elucidate the taxonomic position of the isolated strain. The blue-green oval to rod-shaped cells were 14-18 µm in size, and contained a high amount of phycocyanin pigments. The strain was moderate thermotolerant/alkalitolerant halophile with the optimum conditions for growth at 35 °C, pH 8.5 and 120 g/l of NaCl. Based on 16S rRNA gene sequence phylogeny, the strain was related to members of the 'Euhalothece' subcluster (99%). The whole genome sequence was determined, and the annotated genes showed a 90% sequence similarity to the gas-vacuolate, spindle-shaped Dactylococcopsis salina PCC 8305. The size of the genome was determined to be 5,113,178 bp and contained 4332 protein-coding genes and 69 RNA genes with a G + C content of 46.7%. Genes encoding osmoregulation, oxidative stress, heat shock, persister cells, and UV-absorbing secondary metabolites, among others, were identified. Based on the phylogenetic analysis of the 16S rRNA gene sequences, physiological data, pigment compositions and genomic data, the strain is considered to represent a novel species of Euhalothece.


Assuntos
Cianobactérias/classificação , Cianobactérias/citologia , Cianobactérias/genética , Cianobactérias/isolamento & purificação , Genótipo , Fenótipo , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , Biomassa , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Genes Bacterianos/genética , Tamanho do Genoma , Proteínas de Choque Térmico/genética , Concentração de Íons de Hidrogênio , Osmorregulação/genética , Estresse Oxidativo/genética , Ficocianina/metabolismo , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Tolerância ao Sal , Análise de Sequência de DNA , Cloreto de Sódio/metabolismo , África do Sul , Especificidade da Espécie , Temperatura Ambiente , Sequenciamento Completo do Genoma
20.
Ecotoxicol Environ Saf ; 157: 134-142, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-29621704

RESUMO

The wide presence of polycyclic aromatic hydrocarbons (PAHs) in lakes necessitates a better understanding of cyanobacteria metabolites under the contamination of PAHs. The M. aeruginosa strain PCC7806 was selected to investigate the effects of naphthalene and pyrene on the physiological and biochemical reactions of cyanobacteria, including antioxidant defense system (superoxide dismutase, catalase), intracellular microcystin (MC) content, phycobiliprotein (phycocyanin, allophycocyanin) contents, and specific growth rate. Naphthalene and pyrene altered the growth of the M. aeruginosa strain, reduced the contents of phycocyanin and allophycocyanin, and stimulated the activities of antioxidant enzymes without lipid peroxidation. Remarkably, the intracellular MC content was significantly increased by 68.1% upon exposure of M. aeruginosa to 0.45 mg L-1 naphthalene, and increased by 51.5% and 77.9% upon exposure of M. aeruginosa to 0.45 mg L-1 pyrene and 1.35 mg L-1 pyrene, respectively (P<0.05). Moreover, significant correlations were observed between these physiological reactions, referring that a series of physiological and biochemical reactions in M. aeruginosa worked together against the PAH contamination. Considering that MCs are the most studied cyanobacterial toxins, our results clarified that the promoting MC production by PAH contamination cannot be neglected when making related risk assessments of eutrophic waters.


Assuntos
Toxinas Bacterianas/biossíntese , Toxinas Marinhas/biossíntese , Microcistinas/biossíntese , Microcystis/efeitos dos fármacos , Microcystis/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes Químicos da Água/toxicidade , Antioxidantes/metabolismo , Catalase/metabolismo , Peroxidação de Lipídeos , Microcystis/crescimento & desenvolvimento , Naftalenos/toxicidade , Ficocianina/metabolismo , Pirenos/toxicidade , Superóxido Dismutase/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA