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1.
PLoS One ; 15(4): e0231652, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298342

RESUMO

Lemna species have been used in the food, feed, and pharmaceutical industries, as they are inexpensive sources of proteins, starches, and fatty acids. In this study, we treated L. paucicostata with different concentrations (0.05, 0.1, 0.2, 0.5, or 1 mM) of ethephon. The total dry weight decreased in all ethephon-treated groups compared to the control group. We also investigated the alteration of metabolic profiles induced by ethephon treatment by using gas chromatography-mass spectrometry. This analysis identified 48 metabolites, and the relative levels of most of alcohols, amino acids, fatty acids, and phenols increased by the ethephon treatment, whereas levels of organic acids and sugars decreased. Among these, the highest production of γ-aminobutyric acid (GABA, 5.041 ± 1.373 mg/L) and ferulic acid (0.640 ± 0.071 mg/L) was observed in the 0.5 mM and the 0.2 mM ethephon treatment groups, respectively. These results could be useful for large-scale culture of L. paucicostata with enhanced GABA and ferulic acid content for utilization in the food, feed, cosmetic, and pharmaceutical industries.


Assuntos
Araceae/crescimento & desenvolvimento , Ácidos Cumáricos/metabolismo , Compostos Organofosforados/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Ácido gama-Aminobutírico/metabolismo , Araceae/metabolismo , Metaboloma
2.
Chemosphere ; 251: 126366, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32145575

RESUMO

In this study, the effects of excess nickel (Ni) (100 µM and 200 µM) on growth, antioxidant production, fatty acid, organic and amino acids profiles were examined in Lemna minor L. After 7 days of Ni treatment, chlorosis, growth inhibition and ROS overproduction were observed, accompanied by Ni accumulation. Interestingly, decreased malondialdehyde (MDA) levels were recorded in fronds upon Ni exposure. Fatty acid profiles in Ni-treated L. minor were characterized by increases in saturated- and decreases in unsaturated fatty acids. Ni excess increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), guiacol peroxidase (GPX), and glutathione reductase (GR), and non-enzymatic antioxidants such as glutathione (GSH) and ascorbic acid (AsA); however, deactivation of ascorbate peroxidase (APX) and catalase (CAT) activities were also observed. Disruption of amino acid metabolism in Ni-exposed fronds was evidenced by the accumulation of cysteine, arginine, threonine, valine, isoleucine, leucine, lysine and phenylalanine, as well as reduced levels of tyrosine, alanine, aspartate and proline. Approximately 299%-396%, 139%-254% and 56%-97% concentration increments in citric, malic and oxalic acids, respectively, were concomitantly observed with significant decreases in tartaric, acetic, and fumaric acids in fronds subjected to Ni stress. Taken together, these results indicated that Ni stress induced negative effects on plant physiological, biochemical and morphological processes; however, it is likely that the coordination of metabolites and antioxidants may ameliorate the damaging effects of Ni accumulation.


Assuntos
Araceae/metabolismo , Níquel/metabolismo , Antioxidantes/metabolismo , Araceae/efeitos dos fármacos , Ascorbato Peroxidases/metabolismo , Ácido Ascórbico/farmacologia , Catalase/metabolismo , Ácidos Graxos/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Malondialdeído/metabolismo , Oxirredução , Peroxidase/metabolismo , Peroxidases/metabolismo , Prolina/metabolismo , Superóxido Dismutase/metabolismo
3.
PLoS One ; 15(2): e0228595, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027708

RESUMO

Acid orange 74 (AO74) is a chromium-complex monoazo acid dye widely used in the textile industry. Due to being highly toxic and non-biodegradable, it must be removed from polluted water to protect the health of people and the environment. The aim of this study was two-fold: to evaluate the biosorption of AO74 from an aqueous solution by utilizing HCl-pretreated Lemna sp. (HPL), and to examine dye desorption from the plant material. The maximum capacity of AO74 biosorption (64.24 mg g-1) was reached after 4 h at the most adequate pH, which was 2. The biosorption capacity decreased 25% (to 48.18 mg g-1) during the second biosorption/desorption cycle and remained essentially unchanged during the third cycle. The pseudo-second-order kinetics model concurred well with the experimental results of assays involving various levels of pH in the eluent solution and distinct initial concentrations of AO74. NaOH (0.01 M) was the best eluent solution. The Toth isotherm model best described AO74 biosorption equilibrium data. FTIR analysis confirmed the crucial role of HPL proteins in AO74 biosorption. SEM-EDX and CLSM techniques verified the effective biosorption/desorption of the dye during the three cycles. Therefore, HPL has potential for the removal of AO74 dye from wastewaters.


Assuntos
Araceae/metabolismo , Compostos Azo/isolamento & purificação , Biodegradação Ambiental , Corantes/isolamento & purificação , Adsorção , Compostos Azo/toxicidade , Corantes/toxicidade , Ácido Clorídrico , Concentração de Íons de Hidrogênio , Cinética , Indústria Têxtil , Águas Residuárias/química , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/toxicidade
4.
Aquat Toxicol ; 218: 105352, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31790938

RESUMO

Cadmium (Cd) affects plants and animal health seriously. Ca2+ signals in plant cells are important for adaptive responses to environmental stresses. Here we showed that 50 µM Cd shock stimulated the Ca2+ signal via modifying the instantaneous Ca2+ flux from influx of 17 pmol·cm-2·s-1 to the efflux of 240 pmol·cm-2·s-1 at 100 µm from rhizoid tip. And the Ca2+ signal transferred to the vein and mesophyll cell. The Ca addition decreased the accumulation of Cd. The gene expression of glutamate receptor-like (GLR) proteins, which is activated by Glu and triggers Ca2+ flux, was increased significantly by 24 h Cd stress. Glu content was increased under Cd stress and exogenous Glu triggered the Ca2+ signal in duckweed, while Ca2+ addition caused no influence to Glu content. GABA, which is synthesized from Glu and acts as an inhibitory neurotransmitter, has been decreased with 24 h Cd treatment. GABA addition increased the abscission rate and Glu addition decreased the abscission rate during Cd stress, suggesting that the Glu/GABA ratio is important for responding to Cd. This research shows the sight of the Glu, Ca2+, GABA signaling networks during Cd stress.


Assuntos
Araceae/efeitos dos fármacos , Cádmio/toxicidade , Sinalização do Cálcio/efeitos dos fármacos , Ácido Glutâmico/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Ácido gama-Aminobutírico/metabolismo , Animais , Araceae/metabolismo , Cádmio/metabolismo , Poluentes Químicos da Água/metabolismo
5.
J Chromatogr A ; 1613: 460673, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-31708220

RESUMO

The uptake, translocation and transformation of three UV-blockers commonly employed in sunscreens, namely avobenzone, octocrylene and octisalate from water by Lemna gibba and Cyperus alternifolius was investigated. Reversed phase high performance liquid chromatography coupled to drift-tube ion-mobility quadrupole time-of-flight mass spectrometry was used for analyzing the extracts from the selected plants after incubation with the UV-blockers for one week. For avobenzone several transformation products resulting from hydroxylation, demethylation and oxidation of the parent molecule could be identified by measuring accurate mass, performing MS/MS experiments and by determining their drift-tube collision cross sections employing nitrogen as drift gas. In addition, the plants were subjected to two commercially available sunscreens, providing similar results to those obtained for the standard solutions of the UV-blockers. Finally, a kinetic study on the uptake and transformation of avobenzone, octocrylene and octisalate was conducted over a period of 216 h, revealing that the UV-filters were mostly present in their parent form and only to a smaller part converted into transformation products.


Assuntos
Araceae/metabolismo , Cromatografia Líquida de Alta Pressão , Cyperus/metabolismo , Protetores Solares/farmacocinética , Espectrometria de Massas em Tandem , Acrilatos/farmacocinética , Biotransformação , Espectrometria de Mobilidade Iônica , Propiofenonas/farmacocinética , Salicilatos/farmacocinética
6.
Chemosphere ; 239: 124582, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31514011

RESUMO

Chemical plant protection products (PPPs) is a major group of xenobiotics that are being released in the environment. Although the effects of individual active ingredients (a.i.) on organisms have been studied, information on those of mixtures, is fragmented. Aquatic environments are being polluted by PPPs, posing serious risks for the environment, human, and other organisms. Based on the potential of the model aquatic plant Lemna minor L. in the assessment of PPPs-caused stresses, we have undertaken the task of developing a metabolomics approach for the study of the effects of metribuzin and glyphosate, and their mixtures. Bioassays revealed that metribuzin exhibit higher toxicity than glyphosate and metabolomics highlighted corresponding changes in its metabolome. Treatments had a substantial impact on plants' amino acid pool, resulting in elevated levels of the majority of the identified amino acids. Results indicate that the increased proteolytic activity is a common effect of the a.i. and their mixtures. Additionally, the activation of salicylate-signaling pathways was recorded as a response to the toxicity caused by mixtures. Among the identified metabolites that were discovered as biomarkers were γ-aminobutyric acid (GABA), salicylate, caffeate, α,α-trehalose, and squalene, which play multiple roles in plants' metabolism such as, signaling, antioxidant, and structure protection. No reports exist on the combined effects of PPPs on Lemna and results confirm the applicability of Lemna metabolomics in the study of the combined effects of herbicides and its potential in the monitoring of the environmental health of aquatic environments based on fluctuations of the plant's metabolism.


Assuntos
Araceae/metabolismo , Glicina/análogos & derivados , Herbicidas/toxicidade , Triazinas/toxicidade , Poluentes Químicos da Água/toxicidade , Aminoácidos/metabolismo , Araceae/efeitos dos fármacos , Glicina/toxicidade , Metabolômica , Xenobióticos/metabolismo
7.
Bull Environ Contam Toxicol ; 104(2): 282-287, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31858152

RESUMO

This study involved the development of mathematical linear regression models to describe the relationships between mean plant biomass (M) and population density (D), M and frond diameter (L), frond numbers (N) and L of Lemna minor under different initial population densities (3200, 4450, and 6400 plants/m2), respectively, from the perspective of the self-thinning law. Our results revealed that the value of the allometric exponents for M and D were - 3/2. Further, the concentrations of Zn, Pb, Cu, Fe, and Ni accumulated in L. minor plants were 0.86, 0.32, 0.36, 0.62, and 0.39 mg/kg, respectively. Based on these developed equations and the heavy metal accumulations by L. minor, the phytoremediation capacity of L. minor was quantified via its frond diameters. Overall, the present study provides a cost-effective green method for managing the phytoremediation of heavy metal-contaminated aquatic environments.


Assuntos
Araceae/fisiologia , Recuperação e Remediação Ambiental/métodos , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Araceae/metabolismo , Bioacumulação , Biodegradação Ambiental , Biomassa , Dispersão Vegetal , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia
8.
Environ Toxicol Pharmacol ; 72: 103242, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31473558

RESUMO

The worldwide increase in the consumption of antibiotics is becoming a concern for the scientific community, since the presence of their residues in the wild poses specific challenges, especially in ecotoxicological terms. Currently, antibiotics are used for a wide range of purposes, being used against bacterial diseases but also as growth promoters. As a result, their environmental presence can affect wild organisms, especially those from the aquatic environment. This scenario leads to the need of characterizing the toxicity of antibiotics, especially towards non-target organisms. In this study we selected two species of aquatic macrophytes, Lemna minor and Lemna gibba, which are standard plant species inscribed in ecotoxicological testing guidelines. In this work we characterized the toxic effects of the quinolone antibiotic ciprofloxacin (in levels of 0.005, 0.013, 0.031, 0.078, and 0.195 mg/L), focusing on its potential toxicity towards photosynthetic mechanisms, and pro-oxidant effects. These objectives were attained by measuring the concentrations of chlorophyll a and b, and carotenoids levels. The determination of the quantum yield allowed assessing the effects of ciprofloxacin on the photochemical efficiency of the Photosystem II (PSII). The pro-oxidant effects induced by ciprofloxacin were evaluated by measuring oxidative stress biomarkers, such as catalase activity, and also by determining lipoperoxidation levels. The obtained results showed no differences in terms of the content of both chlorophylls a and b, or any change in the photochemical efficiency of the PSII; however, the global carotenoids content of L. gibba were significantly decreased. The activity of the anti-oxidant enzyme catalase was also significantly increased in L. minor. L. gibba showed a decrease in lipid peroxidation levels, but only for the two lowest concentrations of ciprofloxacin. The global set of data shows the activation of the anti-oxidant defensive system of both plant species, a response that was likely activated by the pro-oxidant character of ciprofloxacin. Our data demonstrate the interference of this therapeutic compound at different levels of plant metabolism, at ecologically relevant concentrations. In fact, the obtained results are of ecological relevance since they illustrate deleterious effects that may compromise the physiology of aquatic non-target plant species.


Assuntos
Antibacterianos/toxicidade , Araceae/efeitos dos fármacos , Ciprofloxacino/toxicidade , Poluentes Químicos da Água/toxicidade , Araceae/metabolismo , Carotenoides/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Água Doce , Peroxidação de Lipídeos/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Proteínas de Plantas/metabolismo
9.
Genes (Basel) ; 10(10)2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31554307

RESUMO

Duckweeds are a family of freshwater angiosperms with morphology reduced to fronds and propagation by vegetative budding. Unlike other angiosperm plants such as Arabidopsis and rice that have physical barriers between their photosynthetic organs and soils, the photosynthetic organs of duckweeds face directly to their nutrient suppliers (waters), therefore, their responses to salinity may be distinct. In this research, we found that the duckweed Spirodela polyrhiza L. accumulated high content of sodium and reduced potassium and calcium contents in large amounts under salt stress. Fresh weight, Rubisco and AGPase activities, and starch content were significantly decreaseded in the first day but recovered gradually in the following days and accumulated more starch than control from Day 3 to Day 5 when treated with 100 mM and 150 mM NaCl. A total of 2156 differentially expressed genes were identified. Overall, the genes related to ethylene metabolism, major CHO degradation, lipid degradation, N-metabolism, secondary metabolism of flavonoids, and abiotic stress were significantly increased, while those involved in cell cycle and organization, cell wall, mitochondrial electron transport of ATP synthesis, light reaction of photosynthesis, auxin metabolism, and tetrapyrrole synthesis were greatly inhibited. Moreover, salt stress also significantly influenced the expression of transcription factors that are mainly involved in abiotic stress and cell differentiation. However, most of the osmosensing calcium antiporters (OSCA) and the potassium inward channels were downregulated, Na+/H+ antiporters (SOS1 and NHX) and a Na+/Ca2+ exchanger were slightly upregulated, but most of them did not respond significantly to salt stress. These results indicated that the ion homeostasis was strongly disturbed. Finally, the shared and distinct regulatory networks of salt stress responses between duckweeds and other plants were intensively discussed. Taken together, these findings provide novel insights into the underlying mechanisms of salt stress response in duckweeds, and can be served as a useful foundation for salt tolerance improvement of duckweeds for the application in salinity conditions.


Assuntos
Araceae/genética , Estresse Salino/genética , Araceae/metabolismo , Sequência de Bases , Cálcio/metabolismo , Parede Celular/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Homeostase , Reguladores de Crescimento de Planta/biossíntese , Reguladores de Crescimento de Planta/genética , Proteínas de Plantas/genética , Potássio/metabolismo , Sódio/metabolismo , Fatores de Transcrição/genética , Transcriptoma
10.
Braz. j. biol ; 79(3): 423-431, July-Sept. 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1001462

RESUMO

Abstract The usage of aquatic plants represents an alternative in the treatment of residues originating from swine. In these systems, one of the N removal methods is the ammonium (NH4 +) uptake and volatilization of ammonia (NH3). In this way, the objective of this work was to evaluate the volatilization rates of NH3 in waste treatment systems swine fluids (SSF) with aquatic macrophytes, as well as the concentration of NH 4+ present in the swine fluids. The experiment was carried out at Campus II/UNOESTE. The treatment systems were composed of 16 boxes of PVC and characterized as: T1 = Control sample 50% of SSF/50% of water; T2 = 50% SSF/50% water + Eichhornia crassipes (Mart.) Solms; T3 = 50% SSF/50% water + Pistia stratiotes L.; T4 = 50% SSF/50% water + Salvinia auriculata Aubl. The design was randomized blocks, with 4 treatments and 4 replicates. The hydrogen potential (pH) and the NH4 + content of the effluent were analyzed weekly, and the volatilization of NH 3 by means of collectors installed in each treatment unit. The presence of aquatic macrophytes promoted the reduction of NH4+ concentration and of the pH values ​​of swine fluids, and this resulted in the reduction of NH3 volatilization rates to the environment, with emphasis on the system with Eichhornia crassipes (Mart.) Solms, which presented the lowest rate of volatilization.


Resumo A utilização de plantas aquáticas representa uma alternativa no tratamento de resíduos oriundos da suinocultura. Nestes sistemas, uma das formas de remoção de nitrogênio (N) é a absorção de amônio (NH4+) pelas plantas, entretanto, também ocorre a volatilização de amônia (NH3). Dessa forma, o objetivo do trabalho foi avaliar as taxas de volatilização de NH3 em sistemas de tratamentos de dejetos líquidos de suínos (DLS) com macrófitas aquáticas, bem como a concentração de NH4+ presente nos dejetos. O experimento foi realizado em área de ambiente aberto no Campus II/UNOESTE. Os sistemas de tratamento foram constituídos de 16 caixas de PVC e caracterizados como: T1 = Testemunha 50% de DLS/50% de água; T2 = 50% de DLS/50% de água + Eichhornia crassipes (Mart.) Solms; T3 = 50% de DLS/50% de água + Pistia stratiotes L.; T4 = 50% de DLS/50% de água + Salvinia auriculata Aubl. O delineamento adotado foi em blocos casualizados, com 4 tratamentos e 4 repetições. Foram analisados o potencial hidrogeniônico (pH) e o teor de NH4 + do efluente semanalmente, e a volatilização de NH3 por meio de coletores instalados em cada unidade de tratamento. A presença das macrófitas aquáticas proporcionou a redução da concentração de NH4+ e dos valores de pH dos dejetos líquidos de suínos, e isto resultou na redução das taxas de volatilização de NH 3 ao meio ambiente, com destaque ao sistema com Eichhornia crassipes (Mart.) Solms, que apresentou a menor taxa de volatilização.


Assuntos
Animais , Eliminação de Resíduos Líquidos , Araceae/metabolismo , Eichhornia/metabolismo , Amônia , Esterco/análise , Suínos , Volatilização , Biodegradação Ambiental , Distribuição Aleatória , Consumo de Água (Saúde Ambiental) , Resíduos Industriais/análise , Criação de Animais Domésticos
11.
Bioresour Technol ; 291: 121853, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377510

RESUMO

The concentration of antibiotics in anaerobically digested swine wastewater (ADSW) usually gradually increases due to the addition of antibiotics in livestock feed. Lemna aequinoctialis was used to treatment synthetic ADSW contaminated by oxytetracycline (OTC) whose concentrations were 0.05, 0.25, 0.50 and 1.00 mg/L, and its influences on NH3-N and TP remove were investigated. The fresh weight, photosynthetic pigment and protein content of duckweed were also investigated. Results have shown that nutrient removal and duckweed growth followed the "dose-response" relationships, and 0.05 mg/L OTC could significantly promote the synthesis of photosynthetic pigments and proteins in duckweed. Meanwhile, the protein content gradually decreased during investigation. More important, the degradation products and possible degradation pathways of OTC were diagrammatized via liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), and twelve intermediates were detected in the duckweed systems. This study can offer a novel view for phytoremediation of ADSW containing antibiotics by aquatic plants.


Assuntos
Antibacterianos/metabolismo , Araceae/metabolismo , Nutrientes , Oxitetraciclina/metabolismo , Águas Residuárias/química , Anaerobiose , Animais , Biodegradação Ambiental , Cromatografia Líquida , Suínos , Espectrometria de Massas em Tandem
12.
PLoS One ; 14(8): e0221755, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31454381

RESUMO

Sustainable management of leachate produced from the dumpsite is one of the major concerns in developing countries Aquatic plants such as duckweed have the potential to remove pollutants from wastewater which can also be cost-effective and feasible options for leachate treatment. Therefore, the objective of our present study was to examine the growth and nutrient removal efficiency of duckweed (Lemna minor) on leachate. Three tests were performed each by growing lemna minor on synthetic leachate under controlled conditions and on dumpsite leachate under natural conditions. During each test, duckweed was grown in 300 ml plastic containers with a surface area of 25.8 cm2. About 60 mg of fresh mass of duckweed was grown on 250 ml leachate at an internal depth of 9.5 cm. Results revealed that, in comparison to synthetic leachate, duckweed removed Chemical Oxygen Demand (COD), nitrogen (N), and phosphorous (P) more efficiently from dumpsite leachate under natural climatic conditions. However, the amounts of N and P absorbed into duckweed body mass were about 16% and 35% respectively more at synthetic leachate under controlled conditions. Maximum growth rate of duckweed (7.03 g m-2 day-1) was also observed for synthetic leachate in comparison to the growth rate of 4.87 g m-2 day-1 at dumpsite leachate. Results of this study provide a useful interpretation of duckweed growth and nutrient removal dynamics from leachate under natural and laboratory conditions.


Assuntos
Araceae/crescimento & desenvolvimento , Araceae/metabolismo , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Tempo (Meteorologia)
13.
Ecotoxicol Environ Saf ; 182: 109397, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31299476

RESUMO

Cadmium (Cd) is a serious threat to plants health. Though some genes have been reported to get involved in the regulation of tolerance to Cd, the mechanisms underlying this process are not fully understood. Na+/H+ antiporter (NHX1) plays an important role in Na+/H+ trafficking. The salt and cadmium stress tolerance were found to be enhanced by NHX1 in duckweed according to our previous study, however, its function in Cd2+ flux under Cd stress has not been studied. Here we explored the Cd2+ flux in wild type (WT) and NHX1 transgenic duckweed (NHX1) under Cd stress. We found that the Cd2+ influx in NHX1 duckweed was significantly declined, followed by an increased Cd2+ efflux after 20 min treatment of Cd, which resulted a less accumulation of Cd in NHX1. Reversely, inhibition of NHX1 by amiloride treatment, enhanced Cd2+ influx in NHX1 duckweed, subsequently delayed Cd2+ efflux in both genotypes of duckweed under Cd2+ shock. H+ efflux in NHX1 duckweed was lower compare with that in WT with 20 min Cd2+ shock. NHX1 also increased the pH value with Cd2+ stress in the transgenic rhizoid. These finding suggested a new function of NHX1 in regulation of Cd2+ and H+ flow during short-term Cd2+ shock.


Assuntos
Araceae/fisiologia , Cádmio/metabolismo , Poluentes Químicos da Água/metabolismo , Araceae/metabolismo , Cádmio/toxicidade , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas/metabolismo , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio , Poluentes Químicos da Água/toxicidade
14.
Environ Sci Pollut Res Int ; 26(26): 26829-26843, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300989

RESUMO

Sediment microbial fuel cell (SMFC) and constructed wetlands with macrophytes have been independently employed for the removal of heavy metals from polluted aquatic ecosystems. Nonetheless, the coupling of macrophytes at the cathode of SMFCs for efficient and synchronous heavy metal removal and bioelectricity generation from polluted river sediment has not been fully explored. Therefore, a novel macrophyte biocathode SMFC (mSMFC) was proposed, developed, and evaluated for heavy metals/organics removal as well as bioelectricity generation in an urban polluted river. With macrophyte-integrated cathode, higher heavy metal removals of Pb 99.58%, Cd 98.46%, Hg 95.78%, Cr 92.60%, As 89.18%, and Zn 82.28% from the sediments were exhibited after 120 days' operation. Total chemical oxygen demand, total suspended solids, and loss on ignition reached 73.27%, 44.42 ± 4.4%, and 5.87 ± 0.4%, respectively. A maximum voltage output of 0.353 V, power density of 74.16 mW/m3, columbic efficiency of 19.1%, normalized energy recovery of 0.028 kWh/m3, and net energy production of 0.015 kWh/m3 were observed in the Lemna minor L. SMFC. Heavy metal and organic removal pathways included electrochemical reduction, precipitation and recovery, bioaccumulation by macrophyte from the surface water, and bioelectrochemical reduction in the sediment. This study established that mSMFC proved as an efficient system for the remediation of heavy metals Pb, Cd, Hg, Cr, As, and Zn, and TCOD in polluted rivers along with bioelectricity generation.


Assuntos
Araceae/metabolismo , Fontes de Energia Bioelétrica , Eletrodos , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Ecossistema , Sedimentos Geológicos/química , Metais Pesados/análise , Rios , Poluentes Químicos da Água/análise , Áreas Alagadas
15.
Bioresour Technol ; 289: 121716, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323721

RESUMO

This study integrated the sugar and carboxylate platforms to enhance duckweed processing in biorefineries. Two or three bioprocesses (ethanol fermentation, acidogenic digestion, and methanogenic digestion) were sequentially integrated to maximize the carbon-to-carbon conversion of wastewater-derived duckweed into bioproducts, through a series of laboratory-scale experiments. Reactors were fed either raw (dried), liquid-hot-water-pretreated, or enzymatically-saccharified duckweed. Subsequently, the target bioproduct was separated from the reactor liquor and the residues further processed. The total bioproduct carbon yield of 0.69 ±â€¯0.07 g per gram of duckweed-C was obtained by sequential acidogenic and methanogenic digestion. Three sequential bioprocesses revealed nearly as high yields (0.66 ±â€¯0.08 g of bioproduct-C per duckweed-C), but caused more gaseous carbon (dioxide) loss. For this three-stage value cascade, yields of each process in conventional units were: 0.186 ±â€¯0.001 g ethanol/g duckweed; 611 ±â€¯64 mg volatile fatty acids as acetic acid/g VS; and 434 ±â€¯0.2 ml methane/g VS.


Assuntos
Araceae/metabolismo , Águas Residuárias/química , Ácido Acético/metabolismo , Anaerobiose , Araceae/química , Etanol/metabolismo , Euryarchaeota/metabolismo , Fermentação , Metano/biossíntese
16.
Environ Sci Pollut Res Int ; 26(23): 24121-24131, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31228067

RESUMO

Although iron oxide occurs naturally in the environment, iron oxide nanoparticles have distinct mobility, reactivity, and toxicity, which can harm the human health and nature. This scenario has motivated the investigation of the toxic effects of iron oxide nanoparticles (akaganeite predominance + hematite) on the aquatic plant Lemna minor. First, nanoparticles were synthesized and characterized; then, different iron oxide NP concentrations were added to Lemna minor culture. After 7 days, all the Lemna minor leaves died, irrespective of the added NP concentration. The iron oxide NP impact on the plant was evaluated based on malondialdehyde (MDA) production from thiobarbituric acid reactive substances (TBARS), which was dose-dependent; i.e., lipid peroxidation in the plant increased with rising iron oxide NP concentration. The chlorophyll content decreased at high iron oxide NP concentrations, which disrupted the light absorption mechanism. Fe accumulation in Lemna minor roots also occurred, which can harm nutrient uptake. Therefore, the iron oxide NP toxic impact on plants and related ecosystems requires further studies in order to prevent environmental damage.


Assuntos
Araceae/efeitos dos fármacos , Compostos Férricos/toxicidade , Nanopartículas/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da Água/toxicidade , Araceae/metabolismo , Clorofila/metabolismo , Clorofila A/metabolismo , Ferro/farmacocinética , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Nanopartículas/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Poluentes Químicos da Água/química
17.
Chemosphere ; 234: 402-408, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31228843

RESUMO

Phytoremediation is a technique in which plants are used to treat contaminated media. The objective of this study was to monitor the influence of the parameters pH, phosphate concentration, and nitrate concentration in the process of arsenic absorption by Lemna valdiviana Phil. The response surface methodology was used to analyze the data to subsidize actions that maximize the phytoremediation process. A central composite rotational design (CCRD) was used with 3 variables including 6 axial points and 6 repetitions at the central point, totaling 20 trials. The plants were exposed to a constant concentration of arsenic in the optimization test of 0.5 mg L-1 (NaAsO2) and varied levels of pH, P-PO4, and N-NO3 in a period of 7 d. At the end of the experiment, the mass of arsenic removed from water and arsenic accumulated in the plants, the arsenic species present, the relative growth rate of plants (RGR), the tolerance index (TI), and the bioaccumulation factor (BAF) were calculated. Lemna valdiviana absorbed a greater amount of As when cultivated under pH conditions between 6.3 and 7.0, readily available phosphorus (P-PO4) concentration of 0.0488 mmol L-1, and nitrogen in the form of 7.9 mmol L-1 nitrate. Under these conditions, the plants were able to accumulate 1190 mg kg-1 As (in dry weight) from the aqueous media and reduce 82% of its initial concentration. Therefore, Lemna valdiviana has been shown to be an arsenic bioaccumulating macrophyte with high phytoremediation potential for media contaminated with the metalloid.


Assuntos
Araceae/metabolismo , Arsênico/farmacocinética , Biodegradação Ambiental , Poluentes Químicos da Água/metabolismo , Arsênico/análise , Concentração de Íons de Hidrogênio , Nitratos , Fosfatos , Poluentes Químicos da Água/análise
18.
Ecotoxicol Environ Saf ; 181: 146-154, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31177079

RESUMO

The impact of lead (Pb) on Spirodela polyrhiza was studied to determine the subcellular distribution, chemical forms, and resulting morphophysiological modifications after treatments with 20 or 80 µM Pb(NO3)2 for 10 days. At the subcellular level, the Pb uptake by S. polyrhiza was mainly compartmentalized in the cell walls (70%), and the majority of Pb (approximately 70%) was extracted using 1 M NaCl and 2% acetic acid (HAc). Visual symptoms of phytotoxcity, surface roughness and closure of stomata, were observed in Pb-treated fronds. Electron-dense precipitates were present in cell walls, and changes to the ultrastructure were most noticeably exhibited in organelle shape, internal organization, and size of the plastoglobules of chloroplasts. Toxic concentrations of Pb induced oxidative stress in fronds, characterized by an accumulation of malondialdehyde (MDA) and decreased chlorophyll and unsaturated fatty acid contents. Pb exposure increased ABS/RC, TRo/RC, DIo/RC, Vj, and φDo (Fv/Fm), indicating that reaction centers were transformed to dissipation sinks, leading to a decrease in the efficiency of photosystem II, which was evident from the decreased values of Fv/Fo, Fv/Fm, ψEo, φEo, RC/ABS, and PIabs. These results indicated that decreased photosynthesis in Pb-treated fronds was partially ascribed to the lower pigment content, inhibition of electron transport, inactivation of the reaction centers, damage to the chloroplast ultrastructure, and stomatal closure. The physiological implications of subcellular distribution and chemical forms are discussed in relation to Pb accumulation and detoxification. However, Pb accumulation significantly impaired photosynthesis and membrane integrity in the fronds of S. polyrhiza.


Assuntos
Araceae/efeitos dos fármacos , Chumbo/toxicidade , Araceae/anatomia & histologia , Araceae/metabolismo , Araceae/ultraestrutura , Clorofila/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/ultraestrutura , Transporte de Elétrons/efeitos dos fármacos , Ácidos Graxos Insaturados/metabolismo , Chumbo/farmacocinética , Malondialdeído/metabolismo , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo
19.
Environ Sci Pollut Res Int ; 26(21): 21340-21350, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31119548

RESUMO

Today, environmental pollution, especially heavy metal pollution, is known as a new and possibly more dangerous pollutant than other environmental ones. For this purpose, the uptake of four aquatic plants in different environments was chosen. In this experiment, four macrophytes, i.e., umbrella palm (Cyperus alternifolius), duckweed (Lemna minor), water hyacinth (Eichhornia crassipes), and canna (Canna × generalis), were studied in five contaminated aquatic environments, i.e., Gohar Rood river, Zarjoob river, Eynak lagoon, Anzali lagoon, and control solution (containing Cd, Cr, Pb, and Zn). The results showed that the highest uptake rates of cadmium, cobalt, vanadium, chromium, zinc, nickel, and lead were observed for duckweed fronds. The highest bioconcentration factor (BCF) of nickel was related to duckweed stem and water hyacinth root, and the highest BCF of cadmium belonged to duckweed fronds and canna root. The highest rate of uptake of cadmium, chromium, zinc, and lead was related to control. The least amount of uptake of several metals by plants was obtained from the water of Gohar Rood and Zarjoob. Generally, based on the results of this study, it can be stated that duckweed is suitable for the uptake of most heavy metals.


Assuntos
Monitoramento Ambiental , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Araceae/metabolismo , Biodegradação Ambiental , Cádmio , Cromo/análise , Cyperus/metabolismo , Eichhornia/metabolismo , Metais Pesados/análise , Níquel , Rios , Poluentes Químicos da Água/análise , Zinco , Zingiberales
20.
Ecotoxicol Environ Saf ; 180: 374-383, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31102845

RESUMO

Ozone (O3) can cause oxidative stress in plants and humans. Catechin is an antioxidant that enriches tea and can probably increase O3 tolerance in plants. To investigate the mechanism of catechin to alleviate O3 stress in plants, Zamiocalcus zamiifolia (an efficient plant for O3 phytoremediation) was sprayed with 5 mM catechin and was used to expose O3 (150-250) under long-term operation (10 cycles). We investigated whether exogenous catechin could enhance O3 removal and alleviate O3 stress through a balanced redox state in plants. Z. zamiifolia sprayed with catechin exhibited higher O3 removal (80.27±3.12%), than Z. zamiifolia without catechin (50.03±2.68%). O3 in the range of 150-250 ppb led to stress in plants, as shown by an increased malondialdehyde content (MDA) and salicylic acid (SA). Whereas under the presence of O3, exogenous catechin could maintain the MDA content and inhibit SA accumulation. Under Z. zamiifolia+catechin+O3 conditions, catechin reacted with O3, which led to the formation of catechin-quinone. The formation of catechin-quinone was confirmed by the depletion of reduced glutathione content (GSH). This catechin-quinone could induce GST and APX genes that are up-regulated approximately 35- and 5-fold, respectively. Hence, Z. zamiifolia+catechin+O3 conditions had higher performance for coping with oxidative stress than did Z. zamiifolia+O3 conditions. This evidence demonstrates that catechin could enhance O3 removal through a balanced redox state in plant cells. Finally, the application of tea extract for enhanced O3 removal is also shown in this study.


Assuntos
Poluentes Atmosféricos/toxicidade , Antioxidantes/metabolismo , Araceae/efeitos dos fármacos , Catequina/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ozônio/toxicidade , Araceae/enzimologia , Araceae/metabolismo , Benzoquinonas/metabolismo , Biodegradação Ambiental , Clorofila/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , Oxirredução , Ácido Salicílico/metabolismo
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