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1.
Nat Commun ; 11(1): 5081, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-33033236

RESUMO

Diatom is an important group of marine algae and contributes to around 20% of the global photosynthetic carbon fixation. Photosystem I (PSI) of diatoms is associated with a large number of fucoxanthin-chlorophyll a/c proteins (FCPIs). We report the structure of PSI-FCPI from a diatom Chaetoceros gracilis at 2.38 Å resolution by single-particle cryo-electron microscopy. PSI-FCPI is a monomeric supercomplex consisting of 12 core and 24 antenna subunits (FCPIs), and 326 chlorophylls a, 34 chlorophylls c, 102 fucoxanthins, 35 diadinoxanthins, 18 ß-carotenes and some electron transfer cofactors. Two subunits designated PsaR and PsaS were found in the core, whereas several subunits were lost. The large number of pigments constitute a unique and huge network ensuring efficient energy harvesting, transfer and dissipation. These results provide a firm structural basis for unraveling the mechanisms of light-energy harvesting, transfer and quenching in the diatom PSI-FCPI, and also important clues to evolutionary changes of PSI-LHCI.


Assuntos
Proteínas de Ligação à Clorofila/química , Diatomáceas/metabolismo , Transferência de Energia , Complexo de Proteína do Fotossistema I/química , Complexos de Proteínas Captadores de Luz/química , Complexos de Proteínas Captadores de Luz/metabolismo , Pigmentos Biológicos/química , Pigmentos Biológicos/metabolismo , Subunidades Proteicas/química
2.
Aquat Toxicol ; 228: 105650, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33035767

RESUMO

Micro(nano)plastics (MPs/NPs) are already present as contaminants in the natural environment globally and have been shown to be difficult to degrade, resulting in the potential for ecological damage and public health concerns. However, the adverse effects of exposure to MPs/NPs by aquatic organisms, especially freshwater microalgae, remains unclear. In the present study, the growth, physiology and transcriptome of the freshwater microalgae Euglena gracilis were comprehensively analyzed following exposure to 1 mg/L of polystyrene (PS) microbeads (5 µm PS-MPs and 100 nm PS-NPs), 0.5 mg/L cadmium (Cd), or a mixture of PS microbeads and Cd for 96 h. Results showed that the toxicity of PS-MPs to microalgae was greater than PS-NPs, inducing increased growth inhibition, oxidative damage and decreased photosynthesis pigment concentrations. PS-MPs alone or in combination with Cd caused cavitation within microalgal cells, as well as increasing the number and volume of vacuoles. The combined exposure toxicity test showed that a combination of Cd + PS-NPs was more toxic than Cd + PS-MPs, which may be explained by the transcriptomic analysis results. Differentially expressed genes (DEGs) in the Cd + PS-NPs group were mainly enriched in metabolism-related pathways, suggesting that algal metabolism was hindered, resulting in aggravation of toxicity. The reduced toxicity induced by Cd + PS-MPs may indicate a response to resist external stress processes. In addition, no adsorption of 0.5 mg/L Cd to 1 mg/L PS microbeads was observed, suggesting that adsorption of MPs/NPs and Cd was not the key factor determining the combined toxicity effects in this study.


Assuntos
Cádmio/toxicidade , Exposição Ambiental , Euglena gracilis/genética , Euglena gracilis/fisiologia , Microalgas/genética , Microesferas , Poliestirenos/toxicidade , Transcrição Genética/efeitos dos fármacos , Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/genética , Organismos Aquáticos/crescimento & desenvolvimento , Euglena gracilis/efeitos dos fármacos , Euglena gracilis/ultraestrutura , Perfilação da Expressão Gênica , Ontologia Genética , Microalgas/efeitos dos fármacos , Microalgas/fisiologia , Microalgas/ultraestrutura , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Pigmentos Biológicos/metabolismo , Poluentes Químicos da Água/toxicidade
3.
Ecotoxicol Environ Saf ; 203: 111019, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888606

RESUMO

Sulfur dioxide (SO2) is one of the most common and harmful air pollutants. High concentrations of SO2 can induce a series of defensive responses in Arabidopsis plants. However, the role of photosynthesis in the plant response to SO2 stress is not clear. Here, we report the photosynthetic responses of Arabidopsis plants to SO2 stress. Exposure to 30 mg/m3 SO2 decreased stomatal conductance (Gs) and transpiration rate (Tr) but increased photosynthetic pigments and net photosynthetic rate (Pn). The contents of carbohydrates and sucrose were not altered. The transcript levels of most genes related to photosystem II (PSII), cytochrome b6/f (Cytb6f), photosystem I (PSI) and carbon fixation were upregulated, revealing one important regulatory circuit for the maintenance of chloroplast homeostasis under SO2 stress. Exposure to SO2 triggered reactive oxygen species (ROS) generation, accompanied by increases in superoxide dismutase (SOD) activity and the contents of cysteine (Cys), glutathione (GSH) and non-protein thiol (NPT), which maintained cellular redox homeostasis. Together, our results indicated that chloroplast photosynthesis was involved in the plant response to SO2 stress. The photosynthetic responses were related to photosynthetic pigments, photosynthesis gene expression and redox regulation.


Assuntos
Poluentes Atmosféricos/toxicidade , Arabidopsis/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Pigmentos Biológicos/metabolismo , Dióxido de Enxofre/toxicidade , Arabidopsis/genética , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Regulação para Baixo , Fotossíntese/genética , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Regulação para Cima
4.
PLoS One ; 15(9): e0239097, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32925956

RESUMO

The eucheumatoids Kappaphycus and Eucheuma are cultivated in tropical or subtropical regions for the production of carrageenan, a hydrocolloid widely used in the food and cosmetic industries. Kappaphycus alvarezii is a highly valued economic crop in the Coral Triangle, with the Philippines, Indonesia and Malaysia ranked among the largest producers. In the absence of measures to mitigate climate change, extreme events including heatwaves, typhoons, severe El Niño and La Niña, are expected to increase in frequency and magnitude. This inadvertently brings adverse effects to the seaweed cultivation industry, especially in the tropics. Temperatures are rapidly reaching the upper limit of biologically tolerable levels and an increase in reports of ice-ice and pest outbreaks is attributable to these shifts of environmental parameters. Nevertheless, few reports on the response of eucheumatoids to a changing environment, in particular global warming, are available. Understanding the responses and possible mechanisms for acclimation to warming is crucial for a sustainable seaweed cultivation industry. Here, the physiological and biochemical responses of K. alvarezii to acute warming indicated that the strain used in the current study is unlikely to survive sudden increases in temperature above 36°C. As temperature increased, the growth rates, photosynthetic performance, phycocolloid quality (carrageenan yield, gel strength and gel viscosity) and pigment content (chlorophyll-a, carotenoid and phycobiliproteins) were reduced while the production of reactive oxygen species increased indicating the occurrence of stress in the seaweeds. This study provides a basis for future work on long term acclimation to elevated temperature and mesocosm-based multivariate studies to identify heat-tolerant strains for sustainable cultivation.


Assuntos
Aquecimento Global , Rodófitas/fisiologia , Aclimatação , Carragenina/análise , Carragenina/metabolismo , Mudança Climática , Fotossíntese , Pigmentos Biológicos/análise , Pigmentos Biológicos/metabolismo , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Rodófitas/química , Rodófitas/crescimento & desenvolvimento , Temperatura
5.
Proc Natl Acad Sci U S A ; 117(30): 17599-17606, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32647063

RESUMO

Fossilized carotenoid hydrocarbons provide a window into the physiology and biochemistry of ancient microbial phototrophic communities for which only a sparse and incomplete fossil record exists. However, accurate interpretation of carotenoid-derived biomarkers requires detailed knowledge of the carotenoid inventories of contemporary phototrophs and their physiologies. Here we report two distinct patterns of fossilized C40 diaromatic carotenoids. Phanerozoic marine settings show distributions of diaromatic hydrocarbons dominated by isorenieratane, a biomarker derived from low-light-adapted phototrophic green sulfur bacteria. In contrast, isorenieratane is only a minor constituent within Neoproterozoic marine sediments and Phanerozoic lacustrine paleoenvironments, for which the major compounds detected are renierapurpurane and renieratane, together with some novel C39 and C38 carotenoid degradation products. This latter pattern can be traced to cyanobacteria as shown by analyses of cultured taxa and laboratory simulations of sedimentary diagenesis. The cyanobacterial carotenoid synechoxanthin, and its immediate biosynthetic precursors, contain thermally labile, aromatic carboxylic-acid functional groups, which upon hydrogenation and mild heating yield mixtures of products that closely resemble those found in the Proterozoic fossil record. The Neoproterozoic-Phanerozoic transition in fossil carotenoid patterns likely reflects a step change in the surface sulfur inventory that afforded opportunities for the expansion of phototropic sulfur bacteria in marine ecosystems. Furthermore, this expansion might have also coincided with a major change in physiology. One possibility is that the green sulfur bacteria developed the capacity to oxidize sulfide fully to sulfate, an innovation which would have significantly increased their capacity for photosynthetic carbon fixation.


Assuntos
Cianobactérias/fisiologia , Fotossíntese , Enxofre/metabolismo , Carotenoides/química , Carotenoides/metabolismo , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Espectrometria de Massas , Fotossíntese/genética , Pigmentos Biológicos/química , Pigmentos Biológicos/metabolismo
6.
Extremophiles ; 24(4): 447-473, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32488508

RESUMO

Pigments are an essential part of everyday life on Earth with rapidly growing industrial and biomedical applications. Synthetic pigments account for a major portion of these pigments that in turn have deleterious effects on public health and environment. Such drawbacks of synthetic pigments have shifted the trend to use natural pigments that are considered as the best alternative to synthetic pigments due to their significant properties. Natural pigments from microorganisms are of great interest due to their broader applications in the pharmaceutical, food, and textile industry with increasing demand among the consumers opting for natural pigments. To fulfill the market demand of natural pigments new sources should be explored. Cold-adapted bacteria and fungi in the cryosphere produce a variety of pigments as a protective strategy against ecological stresses such as low temperature, oxidative stresses, and ultraviolet radiation making them a potential source for natural pigment production. This review highlights the protective strategies and pigment production by cold-adapted bacteria and fungi, their industrial and biomedical applications, condition optimization for maximum pigment extraction as well as the challenges facing in the exploitation of cryospheric microorganisms for pigment extraction that hopefully will provide valuable information, direction, and progress in forthcoming studies.


Assuntos
Pigmentos Biológicos/metabolismo , Bactérias , Fungos , Raios Ultravioleta
7.
Food Chem ; 330: 127189, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32521396

RESUMO

The aim of the study was to assess the effect of incandescent, fluorescent, and LED (RGB (red, green, blue), white cold, white warm) lighting on characteristics of kale sprouts. The highest concentrations of chlorophylls, ß-carotene, lutein, neoxanthin and violaxanthin were found in cotyledons of sprouts growing in RGB LED light. These had the largest proportion of cotyledons to the mass of plants and the highest content of ascorbic acid. The highest contents of protein and total thiocyanates were observed in sprouts cultivated in incandescent light, followed by plants growing under RGB LED light. The application of a conventional bulb led to the lowest yield as well as the smallest amounts of chlorophylls, ß-carotene, lutein and neoxanthin in fresh mass of cotyledons. Of the light sources used, RGB LED treatment allowed plants with the highest content of most of the examined compounds to be obtained.


Assuntos
Ácido Ascórbico/metabolismo , Brassica/metabolismo , Pigmentos Biológicos/metabolismo , Tiocianatos/metabolismo , Clorofila/metabolismo , Luz , beta Caroteno/metabolismo
8.
PLoS One ; 15(4): e0232145, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32324822

RESUMO

Microorganisms are constantly interacting in a given environment by a constant exchange of signaling molecules. In timber, wood-decay fungi will come into contact with other fungi and bacteria. In naturally bleached wood, dark, pigmented lines arising from confrontation of two fungi often hint at such interactions. The metabolites (and pigment) exchange was investigated using the lignicolous basidiomycete Schizophyllum commune, and co-occurring fungi and bacteria inoculated directly on sterilized wood, or on media. In interactions with competitive wood degrading fungi, yeasts or bacteria, different competition strategies and communication types were observed, and stress reactions, as well as competitor-induced enzymes or pigments were analyzed. Melanin, indole, flavonoids and carotenoids were shown to be induced in S. commune interactions. The induced genes included multi-copper oxidases lcc1, lcc2, mco1, mco2, mco3 and mco4, possibly involved in both pigment production and lignin degradation typical for wood bleaching by wood-decay fungi.


Assuntos
Schizophyllum/metabolismo , Bactérias/metabolismo , Pigmentos Biológicos/metabolismo , Metabolismo Secundário/fisiologia , Madeira/microbiologia
9.
Artigo em Inglês | MEDLINE | ID: mdl-32283468

RESUMO

Ecologically relevant low UV-B is reported to alter reactive oxygen species metabolism and anti-oxidative systems through an up-regulation of enzymes of the phenylpropanoid pathway. However, little is known about low UV-B-induced changes in carotenoid profile and their impacts on light harvesting and photoprotection of photosystem II (PSII) in plants. We investigated carotenoids profile, chlorophyll pigments, phenolics, photosynthetic efficiency and growth in Arabidopsis thaliana (Col-0) plants grown under photosynthetically active radiation (PAR), PAR+ ultraviolet (UV)-A and PAR+UV-A+B regimes for 10 days in order to assess plant acclimation to low UV-B radiation. A chlorophyll fluorescence assay was used to examine UV-B tolerance in plants further exposed to acute high UV-B for 4 and 6 h following a 10-day growth under different PAR and UV regimes. We found that both PAR+ UV-A and PAR+UV-A+B regimes had no negative effect on quantum efficiency, electron transport rate, rosette diameter, relative growth rate and shoot dry weight of plants. Chronic PAR+ UV-A regime considerably (P < 0.05) increased violaxanthin (26 %) and neoxanthin (92 %) content in plants. Plant exposure to chronic PAR+UV-A+B significantly (P < 0.05) increased violaxanthin (48 %), neoxanthin (63 %), lutein (33 %), 9-cis ß-carotene (28 %), total ß-carotene (29 %) and total phenolics (108 %). The maximum photochemical efficiency (Fv/Fm) in leaves was found to be positively correlated with total phenolics (rho = 0.81 and rho = 0.91, P < 0.05 for 4 and 6 h, respectively) and non-photochemical quenching (qN) (rho = 0.81 and rho = 0.84, P < 0.05 for 4 and 6 h, respectively) in plants exposed to acute high UV-B for 4 and 6 h following a 10-day growth under chronic PAR+UV-A+B. There was also a significant positive correlation (rho = 0.93, P < 0.01) between qN and lutein content in the plants exposed to acute high UV-B stress for 4 h following plant exposure to chronic PAR+UV-A+B. The findings from our study indicate that plants grown under chronic PAR+UV-A+B displayed higher photoprotection of PSII against acute high UV-B stress than those grown under PAR and PAR+ UV-A regimes. An induction of phenolics and lutein-mediated development of qN were involved in the photoprotection of PSII against UV-B-induced oxidative stress.


Assuntos
Arabidopsis/efeitos da radiação , Carotenoides/metabolismo , Clorofila/metabolismo , Luteína/metabolismo , Fotossíntese/efeitos da radiação , Pigmentos Biológicos/metabolismo , Raios Ultravioleta , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Complexo de Proteína do Fotossistema II/efeitos da radiação
10.
Ecotoxicol Environ Saf ; 195: 110499, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32208213

RESUMO

The objective of this research was to evaluate Ag+ toxicity in Trifolium pratense L. seedlings subjected to increasing doses of Ag+ by determining photosynthetic pigment and malondialdehyde (MDA) contents, microstructure and hereditary substance alterations, changes in activities of antioxidase-superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) as well as the content of total Ag absorbed in vivo with evaluation of root growth. Doses of approximately 80 mg L-1 Ag+ severely affected photosynthetic efficiency in Trifolium pratense L. seedlings promoted by damages in photosynthetic apparatus evidenced by downward trend in photosynthetic pigment contents and obvious chlorosis. Alterations in enzymatic activity, lipid peroxidation, genic material damage and the presence of Ag+in vivo had impacted on photosynthetic machinery as well. A hormesis effect was observed at 60 mg L-1 Ag+ for the photosynthetic pigments and antioxidase for Trifolium pratense L. seedlings. Tissue changes (i.e., roots, stems and leaves) observed in fluorescence microscope with obvious chlorosis, roots blackening and formation of agglomerated black particles, were related to the lesion promoted by excessive ROS in vivo. Asynchronous change of antioxidase activity corresponded to the alteration in the MDA content, indicating the synchronization in the elimination of ROS. The changes occurred in RAPD profiles of treated samples following Ag+ toxicity containing loss of normal bands, appearance of new bands and variation in band intensity compared to the normal plants with a dose-dependent effect. On average, the roots of Trifolium pratense L. immobilized 92.20% of the total Ag absorbed as a metal exclusion response. Root growth was significantly sensitive to Ag+ stress with obvious hormesis, which corresponded to the changes in Ag uptake, demonstrating the functional alterations in plants. To sum up, we suggest that modulating the genotype of Trifolium pratense L. seedlings to bear higher proportion of pollutants is conducive to contamination site treatment.


Assuntos
Dano ao DNA , Fotossíntese/efeitos dos fármacos , Pigmentos Biológicos/metabolismo , Prata/toxicidade , Poluentes do Solo/toxicidade , Trifolium/efeitos dos fármacos , Biodegradação Ambiental , Catalase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/farmacologia , Peroxidase/metabolismo , Fotossíntese/genética , Pigmentos Biológicos/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/metabolismo , Prata/metabolismo , Poluentes do Solo/metabolismo , Superóxido Dismutase/metabolismo , Trifolium/genética , Trifolium/metabolismo
11.
Food Chem ; 318: 126462, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32126463

RESUMO

Degreening is widely used in citrus fruit to extend the market season for economic gains and increase the consumer acceptance. Elevated CO2 was exogenously applied to Satsuma mandarins (Citrus unshiu Marc.) for degreening and its effect on pigment metabolism was investigated. The results revealed 15% CO2 treatment accelerated the citrus fruit peel color change along with the chlorophyll degradation, ß-cryptoxanthin and flavonoids accumulation. The expression of CitSGR, CitNYC, CitChlase, CitPPH, CitPAO and CitRCCR genes involved in chlorophyll metabolism and a set of genes involved in producing ß, ß-xanthophylls were up-regulated by elevated CO2. For flavonoid metabolism, the up-regulated expressions of CitPAL, CitCHS and CitCHI partly explained the increased total flavonoids content. These results showed that 15% CO2 treatment improved the visual appearance of citrus fruits due to its impact on pigment metabolism and also maintained their nutritional value, thus could be employed as a potential commercial technique for citrus degreening.


Assuntos
Dióxido de Carbono/farmacologia , Citrus/fisiologia , Armazenamento de Alimentos/métodos , Pigmentação/efeitos dos fármacos , Pigmentos Biológicos/metabolismo , Adulto , Clorofila/genética , Clorofila/metabolismo , Citrus/química , Citrus/efeitos dos fármacos , Feminino , Flavonoides/genética , Flavonoides/metabolismo , Frutas/química , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Humanos , Masculino , Pigmentação/fisiologia , Pigmentos Biológicos/genética , Paladar , Xantofilas/análise , Xantofilas/metabolismo
12.
Sci Rep ; 10(1): 2654, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-32060345

RESUMO

Ultraviolet (UV) radiation is a small fraction of the solar spectrum, which acts as a key environmental modulator of plant function affecting metabolic regulation and growth. Plant species endemic to the Andes are well adapted to the harsh features of high-altitude climate, including high UV radiation. Maca (Lepidium meyenii Walpers) is a member of Brassicaceae family native to the central Andes of Peru, which grows between 3500 and 4500 m of altitude, where only highland grasses and few hardy bushes can survive. Even though maca has been the focus of recent researches, mainly due to its nutraceutical properties, knowledge regarding its adaptation mechanisms to these particular natural environmental conditions is scarce. In this study, we manipulated solar UV radiation by using UV-transmitting (Control) or blocking (UV-block) filters under field conditions (4138 m above the sea level) in order to understand the impact of UV on morphological and physiological parameters of maca crops over a complete growing season. Compared to the UV-blocking filter, under control condition a significant increase of hypocotyl weight was observed during the vegetative phase together with a marked leaf turnover. Although parameters conferring photosynthetic performance were not altered by UV, carbohydrate allocation between above and underground organs was affected. Control condition did not influence the content of secondary metabolites such as glucosinolates and phenolic compounds in hypocotyls, while some differences were observed in the rosettes. These differences were mainly related to leaf turnover and the protection of new young leaves in control plants. Altogether, the data suggest that maca plants respond to strong UV radiation at high altitudes by a coordinated remobilization and relocation of metabolites between source and sink organs via a possible UV signaling pathway.


Assuntos
Altitude , Ecossistema , Lepidium/fisiologia , Lepidium/efeitos da radiação , Raios Ultravioleta , Clorofila A/metabolismo , Fluorescência , Gases/metabolismo , Lepidium/crescimento & desenvolvimento , Fotossíntese/efeitos da radiação , Pigmentos Biológicos/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Metabolismo Secundário , Solubilidade , Amido/análise , Açúcares/análise
13.
Molecules ; 25(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31906260

RESUMO

Yam yellow pigments (YP) are natural pigments formed during the storage of freshly cut yam (Dioscorea opposita) under certain conditions. The interaction of YP with calf thymus DNA (ctDNA) and its protective effect against DNA oxidative damage were investigated using multiple spectroscopic techniques, competitive binding experiments, viscosity measurements, and gel electrophoresis. Results showed that YP participated in intercalative binding with ctDNA. YP exhibited a protective effect against hydroxyl-induced DNA damage, which was attributed to the high hydroxyl radical scavenging activity of YP. Our findings improve our understanding of the mechanism of interaction between YP and ctDNA, and provide a theoretical basis for the application of YP in the food and drug industry.


Assuntos
Dioscorea/química , Depuradores de Radicais Livres/química , Radical Hidroxila/química , Pigmentos Biológicos/química , Ligação Competitiva , DNA/química , DNA/metabolismo , Dano ao DNA , Dioscorea/metabolismo , Radical Hidroxila/metabolismo , Cinética , Pigmentos Biológicos/isolamento & purificação , Pigmentos Biológicos/metabolismo , Espectrometria de Fluorescência
14.
Sci Rep ; 10(1): 1417, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996735

RESUMO

Phlobaphenes are insoluble phenolic compounds which are accumulated in a limited number of tissues such as seed pericarp and cob glumes, conferring on them a typical red-brown pigmentation. These secondary metabolites, derived from 3-deoxy flavonoids, are thought to have an important role in plants' resistance against various pathogens, e.g. by reducing fungal infection, and also to have beneficial effects on human and animal health due to their high antioxidant power. The aim of this work was to determine the role of phlobaphenes in reducing mycotoxin contamination on maize kernels. We analysed the effect of the P1 (pericarp color 1) gene on phlobaphenes accumulation, pericarp thickness and fumonisins accumulation. Analysing fumonisins accumulation in different genetic backgrounds through three seasons, we found a clear decrease of these toxins through the three years (Wilcoxon test, Z = 2.2, p = 0.0277) in coloured lines compared with the isogenic non-coloured ones. The coloured lines, carrying P1 allele showed an increase of phlobaphenes (about 10-14 fold) with respect to colourless lines. Furthermore there was a correlation between phlobaphenes accumulation and pericarp thickness (R = 0.9318; p = 0.0067). Taken together, these results suggest that the P1 gene plays a central role in regulating phlobaphenes accumulation in maize kernels, and indirectly, also tackles mycotoxins accumulation. The development and cultivation of corn varieties rich in phlobaphenes could be a powerful tool to reduce the loss of both quality and yield due to mycotoxin contamination, increasing the safety and the quality of the maize product.


Assuntos
Flavonoides/metabolismo , Micotoxinas/análise , Pigmentos Biológicos/metabolismo , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Zea mays/metabolismo , Alelos , Vias Biossintéticas/genética , Cor , Resistência à Doença , Flavonoides/imunologia , Fumonisinas/análise , Fusarium/patogenicidade , Pigmentos Biológicos/imunologia , Melhoramento Vegetal , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Zea mays/genética , Zea mays/microbiologia , Zea mays/toxicidade
15.
Molecules ; 25(2)2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31952238

RESUMO

'Ziyan' is a novel anthocyanin-rich tea cultivar with dark purple young shoots. However, how its anthocyanin accumulation is affected by environmental factors, such as ultraviolet (UV), remains unclear. In this study, we observed that UV light treatments stimulated anthocyanin accumulation in 'Ziyan' leaves, and we further analyzed the underlying mechanisms at gene expression and enzyme activity levels. In addition, the catechins and chlorophyll contents of young shoots under different light treatments were also changed. The results showed that the contents of total anthocyanins and three major anthocyanin molecules, i.e., delphinidin, cyanidin, and pelargonidin, were significantly higher in leaves under UV-A, UV-B, and UV-AB treatments than those under white light treatment alone. However, the total catechins and chlorophyll contents in these purple tea plant leaves displayed the opposite trends. The anthocyanin content was the highest under UV-A treatment, which was higher by about 66% than control. Compared with the white light treatment alone, the enzyme activities of chalcone synthase (CHS), flavonoid 3',5'-hydroxylase (F3'5'H), and anthocyanidin synthase (ANS) under UV treatments increased significantly, whereas the leucoanthocyanidin reductase (LAR) and anthocyanidin reductase (ANR) activities reduced. There was no significant difference in dihydroflavonol 4-reductase (DFR) activity under all treatments. Comparative transcriptome analyses unveiled that there were 565 differentially expressed genes (DEGs) of 29,648 genes in three pair-wise comparisons (white light versus UV-A, W vs. UV-A; white light versus UV-B, W vs. UV-A; white light versus UV-AB, W vs. UV-AB). The structural genes in anthocyanin pathway such as flavanone 3-hydroxylase (F3H), F3'5'H, DFR, and ANS, and regulatory gene TT8 were upregulated under UV-A treatment; F3'5'H, DFR, ANS, and UFGT and regulatory genes EGL1 and TT2 were upregulated under UV-AB treatment. However, most structural genes involved in phenylpropanoid and flavonoid pathways were downregulated under UV-B treatment compared with control. The expression of LAR and ANR were repressed in all UV treatments. Our results indicated that UV-A and UV-B radiations can induce anthocyanin accumulation in tea plant 'Ziyan' by upregulating the structural and regulatory genes involved in anthocyanin biosynthesis. In addition, UV radiation repressed the expression levels of LAR, ANR, and FLS, resulting in reduced ANR activity and a metabolic flux shift toward anthocyanin biosynthesis.


Assuntos
Antocianinas/metabolismo , Camellia sinensis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Pigmentos Biológicos/metabolismo , Proteínas de Plantas/metabolismo , Transcriptoma/efeitos da radiação , Raios Ultravioleta , Camellia sinensis/genética , Camellia sinensis/efeitos da radiação , Cor , NADH NADPH Oxirredutases/genética , NADH NADPH Oxirredutases/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Fotossíntese , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Proteínas de Plantas/genética
16.
Anim Genet ; 51(2): 235-248, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31977074

RESUMO

Melanocortin 1-receptor (MC1R) is one of the major genes that controls chicken plumage colour. In this study, we investigated the sequence and haplotype distribution of the MC1R gene in native Japanese chickens, along with non-Japanese chicken breeds. In total, 732 and 155 chickens from 30 Japanese and eight non-Japanese breeds respectively were used. Three synonymous and 11 non-synonymous nucleotide substitutions were detected, resulting in 15 haplotypes (H0-H14). Of these, three were newly found haplotypes (H9, H13 and H14), of which one (H9) was composed of known substitutions C69T, T212C, G274A and G636A. The second one (H13) possessed newly found non-synonymous substitution C919G, apart from the known substitutions C69T, G178A, G274A, G636A and T637C. The third one (H14) comprised a newly discovered substitution C919G in addition to the known C69T, G274A and G409A substitutions. The homozygote for this new haplotype exhibited wt like plumage despite the presence of G274A. In addition to discovering a new nucleotide substitution (C919G) and three new haplotypes, we defined the plumage colour of the bird that was homozygous for the A644C substitution (H5 haplotype) as wheaten-like for the first time; although the substitution has been already reported, its effect was not revealed. Besides detecting the new plumage colour, we also confirmed that the A427G and G274A substitutions contribute in expressing brownish and black plumage colour respectively, as reported by the previous studies. Moreover, we confirmed that the buttercup allele does not express black plumage despite possessing a G274A substitution, under the suppression effect of A644C. In contrast, the birds homozygous for the birchen allele presented solid black plumage, which was contradictory to the previous reports. In conclusion, we revealed a large diversity in the MC1R gene of native Japanese chicken breeds, along with the discovery of a new non-synonymous nucleotide substitution (C919G) and three novel haplotypes (H9, H13 and H14).


Assuntos
Proteínas Aviárias/genética , Galinhas/fisiologia , Plumas/fisiologia , Pigmentação/genética , Polimorfismo de Nucleotídeo Único , Receptor Tipo 1 de Melanocortina/genética , Substituição de Aminoácidos , Animais , Proteínas Aviárias/metabolismo , Galinhas/genética , Cor , Feminino , Haplótipos , Masculino , Pigmentos Biológicos/genética , Pigmentos Biológicos/metabolismo , Receptor Tipo 1 de Melanocortina/metabolismo
17.
Biol Pharm Bull ; 43(1): 179-183, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31902923

RESUMO

Quorum sensing (QS) is a microbial signaling system that regulates the expression of many virulence genes. Herein, we studied five compounds-No. 1: (E)-2-methyl-3- (4-nitro-phenyl)-acrylaldehyde; No. 29-2: pimprinine [5-(1H-indol-3-yl)-2-methyloxazole]; No. 48: (2E,4E)-2-methyl-5-phenyl-2,4-pentadienoic acid; No. 74: (3E,5E)-5-methyl-6-(4-nitrophenyl)-hexa-3,5-dien-2-ol; and No. 130: methyphenazine-1-carboxylate-derived from an actinomycete metabolite library. These compounds were confirmed to be QS inhibitors that reduced violacein production in Chromobacterium violaceum CV026. Additionally, compounds No. 1, No. 74, and No. 130 significantly reduced fluorescent pigment production in Pseudomonas aeruginosa ATCC 27853.


Assuntos
Actinobacteria/metabolismo , Chromobacterium/metabolismo , Pseudomonas aeruginosa/metabolismo , Percepção de Quorum , Indóis/metabolismo , Pigmentos Biológicos/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento
18.
J Agric Food Chem ; 68(1): 59-66, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31816240

RESUMO

Exposure of mature green "Takanotsume" chili fruit to blue and red light-emitting diodes (LEDs) was investigated. The red LED accelerated the red color development of chili as indicated by higher a* and chroma values, as well as lower hue angle and total chlorophyll compared to the blue LED and darkness (control). These were linked to increases in ß-carotene, free-capsanthin, and total carotenoids. The carotenoid biosynthesis-related genes, lycopene-ß-cyclase (Lcyb), ß-carotene hydroxylase (CrtZ), and capsanthin/capsolubin synthase (Ccs), were up-regulated by the red LED after 2 days of the experiment. The blue LED was more effective in increasing the expression of the phytoene synthase (Psy) gene at day 1 of experiment. The total phenolic, vitamin C content, and antioxidant capacity were also higher in the blue LED-treated chili. Results suggest that the responses of each carotenoid-related gene to the light wavelengths and the accumulation of phytochemicals are specific characteristics of this chili cultivar.


Assuntos
Capsicum/metabolismo , Capsicum/efeitos da radiação , Compostos Fitoquímicos/metabolismo , Pigmentos Biológicos/metabolismo , Capsicum/crescimento & desenvolvimento , Carotenoides/metabolismo , Cor , Frutas/química , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Luz , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Xantofilas/metabolismo , beta Caroteno/metabolismo
19.
Biochim Biophys Acta Bioenerg ; 1861(4): 148035, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-31226317

RESUMO

Proper assembly of plant photosystem II, in the appressed region of thylakoids, allows for both efficient light harvesting and the dissipation of excitation energy absorbed in excess. The core moiety of wild type supercomplex is associated with monomeric antennae that, in turn, bind peripheral trimeric LHCII complexes. Acclimation to light environment dynamics involves structural plasticity within PSII-LHCs supercomplexes, including depletion in LHCII and CP24. Here, we report on the acclimation of NoM, an Arabidopsis mutant lacking monomeric LHCs but retaining LHCII trimer. Lack of monomeric LHCs impaired the operation of both photosynthetic electron transport and state transitions, despite the fact that NoM underwent a compensatory over-accumulation of the LHCII complement compared to the wild type. Mutant plants displayed stunted growth compared to the wild type when probed over a range of light conditions. When exposed to short-term excess light, NoM showed higher photosensitivity and enhanced singlet oxygen release than the wild type, whereas long-term acclimation under stress conditions was unaffected. Analysis of pigment-binding supercomplexes showed that the absence of monomeric LHCs did affect the macro-organisation of photosystems: large PSI-LHCII megacomplexes were more abundant in NoM, whereas the assembly of PSII-LHCs supercomplexes was impaired. Observation by electron microscopy (EM) and image analysis of thylakoids highlighted impaired granal stacking and membrane organisation, with a heterogeneous distribution of PSII and LHCII compared to the wild type. It is concluded that monomeric LHCs are critical for the structural and functional optimisation of the photosynthetic apparatus.


Assuntos
Transferência de Energia , Complexos de Proteínas Captadores de Luz/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Tilacoides/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Biomassa , Luz , Mutação/genética , Oxirredução/efeitos da radiação , Fotossíntese/efeitos da radiação , Pigmentos Biológicos/metabolismo , Espectrometria de Fluorescência , Tilacoides/efeitos da radiação , Tilacoides/ultraestrutura
20.
Ecotoxicol Environ Saf ; 190: 110061, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31846859

RESUMO

The objective of this study is to evaluate the effects of physical-chemical and biological variables of the water of the Capibaribe River (state of Pernambuco, Brazil) on leaf anatomy, including ultrastructure and photosynthetic pigment of Salvinia auriculata. Specimens of S. auriculata collected in the Gurjaú River, an area with a low pollution degree, were acclimatized in Hoagland's solution and then subjected to three water samples of the Capibaribe River with different levels of pollution. Twenty-one physical-chemical and biological variables were analyzed according to the Standard Methods for the Examination of Water and Wastewater. The results showed that the samples of the Capibaribe River presented nine parameters that did not comply with the current Brazilian legislation. After 15 days of bioassay, S. auriculata presented variations in mesophyll and cuticle thickness, changes in trichome morphology and accumulation of phenolic compounds. No significant differences were observed for photosynthetic pigment content and leaf length of S. auriculata. Multivariate analyses (PCA and Cluster) showed that the point in the Capibaribe River with the highest number of variables that do not comply with the current legislation was responsible for major structural and chemical changes observed in S. auriculata.


Assuntos
Rios/química , Traqueófitas/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Qualidade da Água , Brasil , Monitoramento Ambiental , Fotossíntese/efeitos dos fármacos , Pigmentos Biológicos/metabolismo , Folhas de Planta/anatomia & histologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/ultraestrutura , Traqueófitas/anatomia & histologia , Traqueófitas/metabolismo , Traqueófitas/ultraestrutura
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