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1.
Int J Mol Sci ; 22(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34639208

RESUMO

Bacillus subtilis BsDyP belongs to class I of the dye-decolorizing peroxidase (DyP) family of enzymes and is an interesting biocatalyst due to its high redox potential, broad substrate spectrum and thermostability. This work reports the optimization of BsDyP using directed evolution for improved oxidation of 2,6-dimethoxyphenol, a model lignin-derived phenolic. After three rounds of evolution, one variant was identified displaying 7-fold higher catalytic rates and higher production yields as compared to the wild-type enzyme. The analysis of X-ray structures of the wild type and the evolved variant showed that the heme pocket is delimited by three long conserved loop regions and a small α helix where, incidentally, the mutations were inserted in the course of evolution. One loop in the proximal side of the heme pocket becomes more flexible in the evolved variant and the size of the active site cavity is increased, as well as the width of its mouth, resulting in an enhanced exposure of the heme to solvent. These conformational changes have a positive functional role in facilitating electron transfer from the substrate to the enzyme. However, they concomitantly resulted in decreasing the enzyme's overall stability by 2 kcal mol-1, indicating a trade-off between functionality and stability. Furthermore, the evolved variant exhibited slightly reduced thermal stability compared to the wild type. The obtained data indicate that understanding the role of loops close to the heme pocket in the catalysis and stability of DyPs is critical for the development of new and more powerful biocatalysts: loops can be modulated for tuning important DyP properties such as activity, specificity and stability.


Assuntos
Bacillus subtilis/enzimologia , Proteínas de Bactérias/metabolismo , Heme/química , Mutação , Peroxidase/química , Peroxidase/metabolismo , Proteínas de Bactérias/genética , Catálise , Domínio Catalítico , Corantes/química , Corantes/metabolismo , Estabilidade Enzimática , Heme/metabolismo , Concentração de Íons de Hidrogênio , Oxirredução , Peroxidase/genética , Conformação Proteica
2.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445682

RESUMO

Dysregulation of gap junction intercellular communication (GJIC) is recognized as one of the key hallmarks for identifying non-genotoxic carcinogens (NGTxC). Currently, there is a demand for in vitro assays addressing the gap junction hallmark, which would have the potential to eventually become an integral part of an integrated approach to the testing and assessment (IATA) of NGTxC. The scrape loading-dye transfer (SL-DT) technique is a simple assay for the functional evaluation of GJIC in various in vitro cultured mammalian cells and represents an interesting candidate assay. Out of the various techniques for evaluating GJIC, the SL-DT assay has been used frequently to assess the effects of various chemicals on GJIC in toxicological and tumor promotion research. In this review, we systematically searched the existing literature to gather papers assessing GJIC using the SL-DT assay in a rat liver epithelial cell line, WB-F344, after treating with chemicals, especially environmental and food toxicants, drugs, reproductive-, cardio- and neuro-toxicants and chemical tumor promoters. We discuss findings derived from the SL-DT assay with the known knowledge about the tumor-promoting activity and carcinogenicity of the assessed chemicals to evaluate the predictive capacity of the SL-DT assay in terms of its sensitivity, specificity and accuracy for identifying carcinogens. These data represent important information with respect to the applicability of the SL-DT assay for the testing of NGTxC within the IATA framework.


Assuntos
Testes de Carcinogenicidade/métodos , Comunicação Celular/fisiologia , Junções Comunicantes/metabolismo , Animais , Bioensaio/métodos , Carcinógenos , Comunicação Celular/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Corantes/metabolismo , Fígado/patologia , Microscopia de Fluorescência/métodos , Ratos
3.
Commun Biol ; 4(1): 871, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267314

RESUMO

Fungal biotechnology is set to play a keystone role in the emerging bioeconomy, notably to address pollution issues arising from human activities. Because they preserve biological diversity, Biological Resource Centres are considered as critical infrastructures to support the development of biotechnological solutions. Here, we report the first large-scale phenotyping of more than 1,000 fungal strains with evaluation of their growth and degradation potential towards five industrial, human-designed and recalcitrant compounds, including two synthetic dyes, two lignocellulose-derived compounds and a synthetic plastic polymer. We draw a functional map over the phylogenetic diversity of Basidiomycota and Ascomycota, to guide the selection of fungal taxa to be tested for dedicated biotechnological applications. We evidence a functional diversity at all taxonomic ranks, including between strains of a same species. Beyond demonstrating the tremendous potential of filamentous fungi, our results pave the avenue for further functional exploration to solve the ever-growing issue of ecosystems pollution.


Assuntos
Biotecnologia/métodos , Corantes/metabolismo , Fungos/metabolismo , Microbiologia Industrial/métodos , Lignina/metabolismo , Plásticos/metabolismo , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/metabolismo , Basidiomycota/classificação , Basidiomycota/genética , Basidiomycota/metabolismo , Fungos/classificação , Fungos/genética , Variação Genética , Geografia , Humanos , Fenótipo , Filogenia , Especificidade da Espécie
4.
J Microbiol Biotechnol ; 31(7): 967-977, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34099601

RESUMO

A total of 37 bacterial isolates were obtained from dye-contaminated soil samples at a textile processing factory in Nakhon Ratchasima Province, Thailand, and the potential of the isolates to decolorize and biotransform azo dye Reactive Red 141 (RR141) was investigated. The most potent bacterium was identified as Paenibacillus terrigena KKW2-005, which showed the ability to decolorize 96.45% of RR141 (50 mg/l) within 20 h under static conditions at pH 8.0 and a broad temperature range of 30-40°C. The biotransformation products were analyzed by using UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy. Gas chromatography-mass spectroscopy analysis revealed four metabolites generated from the reductive biodegradation, namely sodium 3-diazenylnaphthalene-1,5-disulfonate (I), sodium naphthalene-2-sufonate (II), 4-chloro-1,3,5-triazin-2-amine (III) and N1-(1,3,5-triazin-2-yl) benzene-1,4-diamine (IV). Decolorization intermediates reduced phytotoxicity as compared with the untreated dye. However, they had phytotoxicity when compared with control, probably due to naphthalene and triazine derivatives. Moreover, genotoxicity testing by high annealing temperature-random amplified polymorphic DNA technique exhibited different DNA polymorphism bands in seedlings exposed to the metabolites. They compared to the bands found in seedlings subjected to the untreated dye or distilled water. The data from this study provide evidence that the biodegradation of Reactive Red 141 by P. terrigena KKW2-005 was genotoxic to the DNA seedlings.


Assuntos
Compostos Azo/metabolismo , Corantes/metabolismo , Paenibacillus/metabolismo , Poluentes Químicos da Água/metabolismo , Compostos Azo/toxicidade , Biotransformação , Corantes/toxicidade , Concentração de Íons de Hidrogênio , Mutação/efeitos dos fármacos , Paenibacillus/classificação , Paenibacillus/genética , Paenibacillus/isolamento & purificação , Filogenia , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/crescimento & desenvolvimento , Temperatura , Têxteis , Tailândia , Vigna/efeitos dos fármacos , Vigna/genética , Vigna/crescimento & desenvolvimento , Descoloração da Água , Poluentes Químicos da Água/toxicidade
5.
Ecotoxicol Environ Saf ; 217: 112237, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33892342

RESUMO

Laccases and laccase-mediator systems (LMS) are versatile catalysts that can oxidize a broad range of substrates coupled to the sole reduction of dioxygen to water. They possess many biotechnological applications in paper, textile, and food industries, bioethanol production, organic synthesis, detection and degradation of pollutants, and biofuel cell development. In particular, bacterial laccases are getting relevance due to their activity in a wide range of pH and temperature and their robustness under harsh conditions. However, the enzyme and the redox mediator's availability and costs limit their large-scale commercial use. Here we demonstrate that ß-(10-phenothiazyl)-propionic acid can be used as an efficient and low-cost redox mediator for decolorizing synthetic dyes by the recombinant laccase SilA from Streptomyces ipomoeae produced in E. coli. This new LMS can decolorize more than 80% indigo carmine and malachite green in 1 h at pH = 8.0 and 2 h in tap water (pH = 6.8). Furthermore, it decolorized more than 40% of anthraquinone dye remazol brilliant blue R and 80% of azo dye xylidine ponceau in 5 h at 50 °C, pH 8.0. It supported at least 3 decolorization cycles without losing activity, representing an attractive candidate for a cost-effective and environmentally friendly LMS functional at neutral to alkaline pH.


Assuntos
Biodegradação Ambiental , Corantes/química , Lacase/metabolismo , Antraquinonas , Compostos Azo , Corantes/metabolismo , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Índigo Carmim , Oxirredução , Streptomyces , Temperatura
6.
Arch Microbiol ; 203(5): 2669-2680, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33713141

RESUMO

The optimization of the bacterium Pseudomonas stutzeri SPM-1, obtained from textile wastewater dumping sites of Surat, Gujarat was studied for the degradation of the textile azo dye Procion Red-H3B. The strain showed significant activities of azoreductase (95%), laccase (76%) and NADH-DCIP reductase (88%) at 12, 10 and 8 h of growth, respectively, indicating the evidence for reductive cleavage of the dye. The optimization was carried on phenanthrene enrichment medium followed by exposing it to variable environmental factors and nutritional sources. The complete decolourization of dye (50 mg/L) happened within 20 h of incubation at pH 8 and temperature 32 ± 0.2 °C under microaerophilic condition. Decolourization was monitored with the shifting of absorbance peak in UV-Vis spectrophotometry and HPLC analysis. The changes in the functional groups were confirmed by the presence of new peaks in FT-IR data. GC-MS analysis helped in recognizing the degraded dye compounds thus elucidating the proposed pathway for Procion Red-H3B. The potential of bioremediation process was completed by phytotoxicity test using two plants Vigna radiata and Cicer arietinum. Our study concludes that the strain Pseudomonas stutzeri SPM-1, with its rapid decolourization efficiency holds noteworthy prospective in industrial application for textile wastewater treatment.


Assuntos
Compostos Azo/metabolismo , Biodegradação Ambiental , Corantes/metabolismo , Pseudomonas stutzeri/metabolismo , Triazinas/metabolismo , Cicer/efeitos dos fármacos , Corantes/química , Corantes/toxicidade , Cromatografia Gasosa-Espectrometria de Massas , Lacase/metabolismo , Nitrorredutases/metabolismo , Estudos Prospectivos , Quinona Redutases/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Têxteis , Triazinas/toxicidade , Vigna/efeitos dos fármacos , Águas Residuárias/microbiologia , Purificação da Água
7.
Ecotoxicol Environ Saf ; 215: 112093, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33721667

RESUMO

Organic aromatic compounds used for dyeing and coloring in the textile industry are persistent and hazardous pollutants that must be treated before they are discharged into rivers and surface waters. Therefore, we investigated the potential of the white rot fungus Phanerochaete velutina to decolorize commonly used reactive dyes. The fungus decolorized in average 55% of Reactive Orange 16 (RO-16) after 14 days at a maximum rate of 0.09 d-1 and a half-life of 8 days. Furthermore, we determined the inhibitory effects of co-present inorganic contaminants Nickel (Ni) and Cobalt (Co) salts on the decolorization potential and determined IC50 values of 5.55 mg l-1 for Co and a weaker inhibition by Ni starting from a concentration of 20 mg l-1. In the decolorization assay for Remazol Brilliant Blue R (RBBR) we observed the interference of a metabolite of P. velutina, which did not allow us to investigate the kinetics of the reaction. The formation of the metabolite, however, could be used to obtain IC50 values of 3.37 mg l-1 for Co and 7.58 mg l-1 for Ni. Our results show that living white rot fungi, such as P. velutina, can be used for remediation of dye polluted wastewater, alternatively to enzyme mixtures, even in the co-presence of heavy metals.


Assuntos
Biodegradação Ambiental , Corantes/metabolismo , Phanerochaete/metabolismo , Poluentes Químicos da Água/metabolismo , Antraquinonas , Compostos Azo , Cobalto , Metais Pesados , Níquel , Sais , Indústria Têxtil , Têxteis , Águas Residuárias , Poluentes Químicos da Água/análise
8.
Braz J Microbiol ; 52(2): 761-771, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33754316

RESUMO

Extensive utilization of the synthetic dyes in various industries is leading to water and soil contamination and ultimately impacting the humans. A research study was conducted for investigating the biodecolorization and biotransformation of Mordant Black 11 dye. For this purpose, potential of biofilm forming bacteria Klebsiella pneumoniae MB398 isolated from effluent outlets of Tops Food Industry, Hattar, Pakistan, was assessed to decolorize and transform Mordant Black 11 dye. Bacterial strain MB398 exhibited the capability of growing optimally at acidic pH (pH 6.0). Klebsiella pneumoniae MB398 efficiently decolorized Mordant Black 11 dye (64.55%) in aerobic environment at pH 6.0 and 37 °C over 24 h, which further increased to 75.35% over a period of 72 h of incubation. Strain MB398 also exhibited the capability of decolorizing Mordant Black 11 dye in the presence of cadmium (63.71%), chromium (61.78%), and copper (61.50%), respectively. UV-VIS spectrophotometric analysis, FTIR, and HPLC spectra were also indicative of biotransformation of dye molecules by Klebsiella pneumoniae MB398. GC-MS analysis of Mordant Black 11 dye revealed formation of 9 novel and unique metabolites including phenol,2,4-bis(1,1-dimethylethyl); 9-eicosene, (E); ethanol,2,2-(2-propenyloxy); acetic acid, benzene; 1-naphthol; methyl formate; valeraldehyde,2,4-dimethyl; and 7-hexadecene (Z). A possible metabolic pathway depicting the biotransformation of Mordant Black 11 dye by Klebsiella pneumoniae MB398 was projected. Findings of the current research study strongly suggest application of Klebsiella pneumoniae MB398 for developing large scale bioremediation strategies for the abatement of synthetic dyes to retain environmental sustainability in bioeconomic way.


Assuntos
Corantes/metabolismo , Klebsiella/metabolismo , Biodegradação Ambiental , Biotransformação , Corantes/química , Klebsiella/classificação , Klebsiella/genética , Klebsiella/isolamento & purificação , Redes e Vias Metabólicas , Paquistão , Águas Residuárias/microbiologia
9.
Biochemistry ; 60(15): 1226-1241, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33784066

RESUMO

The catalytic activity of dye-decolorizing peroxidases (DyPs) toward bulky substrates, including anthraquinone dyes, phenolic lignin model compounds, or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), is in strong contrast to their sterically restrictive active site. In two of the three known subfamilies (A- and C/D-type DyPs), catalytic protein radicals at surface-exposed sites, which are connected to the heme cofactor by electron transfer path(s), have been identified. So far in B-type DyPs, there has been no evidence for protein radical formation after activation by hydrogen peroxide. Interestingly, B-type Klebsiella pneumoniae dye-decolorizing peroxidase (KpDyP) displays a persistent organic radical in the resting state composed of two species that can be distinguished by W-band electron spin echo electron paramagnetic resonance (EPR) spectroscopy. Here, on the basis of a comprehensive mutational and EPR study of computationally predicted tyrosine and tryptophan variants of KpDyP, we demonstrate the formation of tyrosyl radicals (Y247 and Y92) and a radical-stabilizing Y-W dyad between Y247 and W18 in KpDyP, which are unique to enterobacterial B-type DyPs. Y247 is connected to Y92 by a hydrogen bonding network, is solvent accessible in simulations, and is involved in ABTS oxidation. This suggests the existence of long-range electron path(s) in B-type DyPs. The mechanistic and physiological relevance of the reaction mechanism of B-type DyPs is discussed.


Assuntos
Corantes/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Modelos Moleculares , Peroxidases/química , Peroxidases/metabolismo , Tirosina , Cor , Transporte de Elétrons , Radicais Livres/química , Conformação Proteica
10.
J Biosci Bioeng ; 131(5): 565-571, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33582015

RESUMO

Cyclic voltammetry was successfully applied to in-vivo monitoring of leuco-indigo in indigo-fermenting suspensions under quiescent conditions without deoxygenation; the working and counter electrodes were kept on the surface of each suspension by a polyethylene vinyl alcohol tube holder. The anodic peak current was used as a measure of the leuco-indigo concentration. The voltammetric wave shape suggested partial solubilization of the indigo with some macromolecules in the fermenting suspensions, which lead to an in-situ method without any electrode surface pretreatment. The anodic peak current well reflected the dyeing activity of a suspensions. The results obtained for laboratory-level fermentation systems clarified the number of days required for dye fermentation, the effectiveness of addition of old suspension as an additive for preparing fresh fermenting suspensions, and the importance of addition of a nitrogen-based nutrient as well as a glucose-based one to recover the indigo-reducing activity. The method can also be applied to determine the amounts of indigo in used dye suspensions and extracts of fermented indigo leaves (sukumo) by adding a chemical reduction pretreatment.


Assuntos
Corantes/química , Fermentação , Índigo Carmim/química , Corantes/metabolismo , Eletroquímica , Eletrodos , Índigo Carmim/metabolismo , Suspensões
11.
Int J Biol Macromol ; 176: 37-46, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33571594

RESUMO

Although lots of tyrosinases have been isolated from bacteria, few studies are focused on tyrosinases from Bacillus sp.. In this study, a tyrosinase from B. aryabhattai TCCC 111983 (TYR) was functionally expressed, purified, and then biochemically characterized. The recombinant tyrosinase (rTYR) presented a good catalytic activity in a broad temperature and pH range, retaining over 60% of the relative activity at 30 °C-90 °C and 45% at pH 3.0 to 10.0. Especially, rTYR exhibited 20% of its maximum activity at 0 °C, and it also showed a variable stability towards different effectors. It presented high tolerance towards salinity and chloride, retaining 81% of its original activity in 2 M NaCl. Kinetic parameters indicated that rTYR displayed a relatively good affinity for both l-tyrosine and l-DOPA. Additionally, rTYR demonstrated remarkable advantages on efficient decolorizing azo and anthraquinonic food dyes (carmine and erythrosin), and more five industrial dyes with or without mediators in acidic, neutral, and alkaline conditions. As the first report on the tyrosinase from B. aryabhattai, the aforementioned results indicated that rTYR would be potential for food industrial applications.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/química , Monofenol Mono-Oxigenase/química , Sequência de Aminoácidos , Bacillus/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Corantes/metabolismo , Estabilidade Enzimática , Genes Bacterianos , Concentração de Íons de Hidrogênio , Microbiologia Industrial , Cinética , Modelos Moleculares , Monofenol Mono-Oxigenase/genética , Monofenol Mono-Oxigenase/metabolismo , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Temperatura
12.
Int J Biol Macromol ; 177: 58-82, 2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33577817

RESUMO

Lignin peroxidase (LiP) seems to be a catalyst for cleaving high-redox potential non-phenolic compounds with an oxidative cleavage of CC and COC bonds. LiP has been picked to seek a practical and cost-effective alternative to the sustainable mitigation of diverse environmental contaminants. LiP has been an outstanding tool for catalytic cleaning and efficient mitigation of environmental pollutants, including lignin, lignin derivatives, dyes, endocrine-disrupting compounds (EDCs), and persistent organic pollutants (POPs) for the past couple of decades. The extended deployment of LiP has proved to be a promising method for catalyzing these environmentally related hazardous pollutants of supreme interest. The advantageous potential and capabilities to act at different pH and thermostability offer its working tendencies in extended environmental engineering applications. Such advantages led to the emerging demand for LiP and increasing requirements in industrial and biotechnological sectors. The multitude of the ability attributed to LiP is triggered by its stability in xenobiotic and non-phenolic compound degradation. However, over the decades, the catalytic activity of LiP has been continuing in focus enormously towards catalytic functionalities over the available physiochemical, conventional, catalyst mediated technology for catalyzing such molecules. To cover this literature gap, this became much more evident to consider the catalytic attributes of LiP. In this review, the existing capabilities of LiP and other competencies have been described with recent updates. Furthermore, numerous recently emerged applications, such as textile effluent treatment, dye decolorization, catalytic elimination of pharmaceutical and EDCs compounds, have been discussed with suitable examples.


Assuntos
Lignina/metabolismo , Peroxidases/metabolismo , Biodegradação Ambiental/efeitos dos fármacos , Catálise , Corantes/metabolismo , Poluentes Ambientais/metabolismo , Humanos , Xenobióticos/metabolismo
13.
Ecotoxicol Environ Saf ; 214: 112084, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33640726

RESUMO

Direct Black G (DBG) is a highly toxic synthetic azo dye which is difficult to degrade. Biological treatment seems to be a promising option for the treatment of azo dye containing effluent. A thermophilic bacterial strain (Anoxybacillus sp. PDR2) previously isolated from the soil can effectively remove DBG. However, the molecular underpinnings of DBG degradation and the microbial detoxification ability remains unknown. In the present study, the genetic background of PDR2 for the efficient degradation of DBG and its adaptation to azo dye-contaminated environments was revealed by bioinformatics. Moreover, the possible biodegradation pathways were speculated based on the UV-vis spectral analysis, FTIR, and intermediates identified by LC-MS. Additionally, phytotoxicity and the comet experiment studies clearly indicated that PDR2 converts toxic azo dye (DBG) into low toxicity metabolites. The combination of biodegradation pathways and detoxification analysis were utilized to explore the molecular degradation mechanism and bioremediation of azo dye for future applications. These findings will provide a valuable theoretical basis for the practical treatment of azo dye wastewater.


Assuntos
Anoxybacillus/metabolismo , Compostos Azo/metabolismo , Biodegradação Ambiental , Anoxybacillus/genética , Bactérias/metabolismo , Cor , Corantes/metabolismo , Humanos , Solo , Águas Residuárias
14.
Artigo em Inglês | MEDLINE | ID: mdl-33639069

RESUMO

Perls' Prussian blue (PPB) stain recognizes Fe3+ associated with hemosiderin. The employment of this stain in clinical medicine and research has been extensive and novel applications continue to evolve. Ferruginous bodies are intracellular structures in lung tissue, bronchoalveolar lavage (BAL), and sputum that stain with PPB. Inhaled, insoluble, biopersistent particles and fibers are phagocytosed by lung macrophages and thought to be coated, either partially or completely, with an iron-containing protein at the interface forming a ferruginous body. These structures can be categorized as ferruginous bodies having either an inorganic or a carbonaceous core (e.g., asbestos and byssinotic bodies, respectively). In lung tissue, BAL, and sputum, the only cells that stain with PPB are macrophages. These are described as iron- and hemosiderin-laden macrophages and called either siderophages or sideromacrophages. Siderophages can be observed in the lung tissue, BAL, and sputum after various exposures and can also be associated with many different pulmonary and extrapulmonary diseases.


Assuntos
Líquido da Lavagem Broncoalveolar/química , Corantes/metabolismo , Ferrocianetos/metabolismo , Pulmão/química , Macrófagos/química , Escarro/química
15.
Molecules ; 26(4)2021 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33562176

RESUMO

In the last 3 years alone, over 10,000 publications have appeared on the topic of dye removal, including over 300 reviews. Thus, the topic is very relevant, although there are few articles on the practical applications on an industrial scale of the results obtained in research laboratories. Therefore, in this review, we focus on advanced oxidation methods integrated with biological methods, widely recognized as highly efficient treatments for recalcitrant wastewater, that have the best chance of industrial application. It is extremely important to know all the phenomena and mechanisms that occur during the process of removing dyestuffs and the products of their degradation from wastewater to prevent their penetration into drinking water sources. Therefore, particular attention is paid to understanding the mechanisms of both chemical and biological degradation of dyes, and the kinetics of these processes, which are important from a design point of view, as well as the performance and implementation of these operations on a larger scale.


Assuntos
Corantes/isolamento & purificação , Corantes/metabolismo , Poluentes Ambientais/isolamento & purificação , Poluentes Ambientais/metabolismo , Biodegradação Ambiental , Oxirredução
16.
Int J Mol Sci ; 22(3)2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33573012

RESUMO

The basidiomycete Pleurotus sapidus produced a dye-decolorizing peroxidase (PsaPOX) with alkene cleavage activity, implying potential as a biocatalyst for the fragrance and flavor industry. To increase the activity, a daughter-generation of 101 basidiospore-derived monokaryons (MK) was used. After a pre-selection according to the growth rate, the activity analysis revealed a stable intraspecific variability of the strains regarding peroxidase and alkene cleavage activity of PsaPOX. Ten monokaryons reached activities up to 2.6-fold higher than the dikaryon, with MK16 showing the highest activity. Analysis of the PsaPOX gene identified three different enzyme variants. These were co-responsible for the observed differences in activities between strains as verified by heterologous expression in Komagataella phaffii. The mutation S371H in enzyme variant PsaPOX_high caused an activity increase alongside a higher protein stability, while the eleven mutations in variant PsaPOX_low resulted in an activity decrease, which was partially based on a shift of the pH optimum from 3.5 to 3.0. Transcriptional analysis revealed the increased expression of PsaPOX in MK16 as reason for the higher PsaPOX activity in comparison to other strains producing the same PsaPOX variant. Thus, different expression profiles, as well as enzyme variants, were identified as crucial factors for the intraspecific variability of the PsaPOX activity in the monokaryons.


Assuntos
Alcenos/metabolismo , Corantes/metabolismo , Proteínas Fúngicas/metabolismo , Peroxidase/metabolismo , Pleurotus/metabolismo , Biotransformação , Proteínas Fúngicas/genética , Modelos Moleculares , Mutação , Peroxidase/genética , Pleurotus/enzimologia , Pleurotus/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transcriptoma
17.
J Gen Physiol ; 153(4)2021 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-33538764

RESUMO

In intact muscle fibers, functional properties of ryanodine receptor (RYR)-mediated sarcoplasmic reticulum (SR) Ca2+ release triggered by activation of the voltage sensor CaV1.1 have so far essentially been addressed with diffusible Ca2+-sensitive dyes. Here, we used a domain (T306) of the protein triadin to target the Ca2+-sensitive probe GCaMP6f to the junctional SR membrane, in the immediate vicinity of RYR channels, within the triad region. Fluorescence of untargeted GCaMP6f was distributed throughout the muscle fibers and experienced large Ca2+-dependent changes, with obvious kinetic delays, upon application of voltage-clamp depolarizing pulses. Conversely, T306-GCaMP6f localized to the triad and generated Ca2+-dependent fluorescence transients of lower amplitude and faster kinetics for low and intermediate levels of Ca2+ release than those of untargeted GCaMP6f. By contrast, model simulation of the spatial gradients of Ca2+ following Ca2+ release predicted limited kinetic differences under the assumptions that the two probes were present at the same concentration and suffered from identical kinetic limitations. At the spatial level, T306-GCaMP6f transients within distinct regions of a same fiber yielded a uniform time course, even at low levels of Ca2+ release activation. Similar observations were made using GCaMP6f fused to the γ1 auxiliary subunit of CaV1.1. Despite the probe's limitations, our results point out the remarkable synchronicity of voltage-dependent Ca2+ release activation and termination among individual triads and highlight the potential of the approach to visualize activation or closure of single groups of RYR channels. We anticipate targeting of improved Ca2+ sensors to the triad will provide illuminating insights into physiological normal RYR function and its dysfunction under stress or pathological conditions.


Assuntos
Cálcio , Canal de Liberação de Cálcio do Receptor de Rianodina , Cálcio/metabolismo , Sinalização do Cálcio , Corantes/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/metabolismo
18.
World J Microbiol Biotechnol ; 37(1): 8, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33392823

RESUMO

Dye-decolorization is one of the most important steps in dye-polluted wastewater treatment. The dye-decolorization bacteria were isolated from active sludge collected from wastewater treating pond of a dyeing and printing plant using serial dilution method. Among the 44 bacteria isolates from the active sludge, the strain Bacillus amyloliquefaciens W36 was found to have strong ability in dye-decolorization. The effects of carbon source, nitrogen sources, C/N, metal ions, temperature, pH, and rotation speed for dye-decolorization were investigated. The optimum decolorization conditions were that the strain was grown in enriched mineral salt medium (EMSM) using maltose 1 g/L, (NH4)2SO4 1 g/L as carbon and nitrogen source respectively, supplemented with 100 mg/L different dyes (pH 6.0), at 30 °C, 200 rpm from 48 to 96 h. The bacteria could aerobically decolorize dyes, such as Coomassie brilliant blue (95.42%), Bromcresol purple (93.34%), Congo red (72.37%) and Sarranine (61.7%), within 96 h. The dyes decolorization products were analyzed by ultra-violet and visible (UV-vis) spectroscopy before and after decolorization, which indicated that the four dyes were significantly degraded by the strain. The results indicated that the bacteria Bacillus amyloliquefaciens W36 could be used in dye-polluted wastewater treatment.


Assuntos
Bacillus amyloliquefaciens/isolamento & purificação , Bacillus amyloliquefaciens/metabolismo , Corantes/metabolismo , Esgotos/microbiologia , Descoloração da Água/métodos , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biodegradação Ambiental , Púrpura de Bromocresol/metabolismo , Carbono/metabolismo , Vermelho Congo/metabolismo , Nitrogênio/metabolismo , Corantes de Rosanilina/metabolismo , Águas Residuárias/microbiologia , Purificação da Água
19.
Ecotoxicol Environ Saf ; 208: 111712, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396043

RESUMO

The photocatalytic process is an environmentally-friendly procedure that has been well known in the destruction of organic pollutants in water. The multiple semiconductor heterojunctions are broadly applied to enhance the photocatalytic performances in comparison to the single semiconductor. Polymeric semiconductors have received much attention as inspiring candidates owing to their adjustable optical absorption features and simply adaptable electronic structure. The shortcomings of the current photocatalytic system, which restricts their technical applications incorporate fast charge recombination, low-utilization of visible radiation, and low immigration capability of the photo-induced electron-hole. This paper indicates the novel fabrication of new CuI/g-C3N4 nanocomposite by hydrothermal and ultrasound-assisted co-precipitation methods. The structure, shape, and purity of the products were affected by different weight percentages and fabrication processes. Electron microscope unveils that CuI nanoparticles are distributed on g-C3N4. The bandgap of pure carbon nitride is estimated at 2.70 eV, and the bandgap of the nanocomposite has increased to 2.8 eV via expanding the amount of CuI. The CuI/C3N4 nanocomposite has a great potential to degrade cationic and anionic dyes in high value because of its appropriate bandgap. It can be a great catalyst for water purification. The photocatalytic efficiency is affected by multiple factors such as types of dyes, fabrication methods, the light sources, mass ratios, and scavengers. The fabricated CuI/C3N4 nanocomposite exposes higher photocatalytic performance than the pure C3N4 and CuI. The photocatalytic efficiency of nanocomposite is enhanced by enhancing the amount of CuI. Besides, the fabricated CuI/C3N4 revealed remarkable reusability without the obvious loss of photocatalytic activity. The antibacterial activity of the specimens reveals that the highest antimicrobial activities are revealed against P. aeruginosa and E. coli. These results prove that the nanocomposite possesses high potential for killing bacteria, and it can be nominated as a suitable agent against bacteria.


Assuntos
Antibacterianos/farmacologia , Cobre/química , Grafite/química , Iodetos/química , Compostos de Nitrogênio/química , Poluentes Químicos da Água/isolamento & purificação , Antibacterianos/química , Catálise , Corantes/química , Corantes/isolamento & purificação , Corantes/metabolismo , Cobre/farmacologia , Grafite/farmacologia , Iodetos/farmacologia , Luz , Nanocompostos/química , Compostos de Nitrogênio/farmacologia , Poluentes Químicos da Água/química , Purificação da Água/métodos
20.
Cell Biol Int ; 45(3): 558-568, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33049086

RESUMO

Ultrasound (US) assisted drug delivery is receiving interest in treating posterior eye diseases, such as diabetic retinopathy due to its ability to maximize drug penetration into difficult to reach tissues. Despite its promise, the technique has only been investigated using healthy cell and tissue models, with no evidence to date about its safety in active disease. As a result, the aim of this study was to evaluate the safety of US administration in vitro in retinal pigment epithelial cells under normal and high glucose conditions. US protocols within the presently accepted safety threshold were applied and their influence on cell membrane and tight junction integrity as well as intracellular inflammation was evaluated using lactate dehydrogenase (LDH), zona occludens-1 (ZO-1), fluorescein isothiocyanate (FITC)-dextran dye leak and nuclear factor-kappaB (NF-κB) assays, respectively. Under high glucose conditions, US application increased LDH release and resulted in loss of ZO-1 labeling at 2 h; however, normal levels were restored within 24 h. US within its safety parameters did not induce any FITC-dextran dye leak or NF-κB nuclear translocation in normal or high glucose conditions. In conclusion, our results suggest that while high glucose conditions increase cell susceptibility to US-mediated stress, basal conditions can be restored within 24 h without long-lasting cell damage.


Assuntos
Células Epiteliais/patologia , Hiperglicemia/patologia , Epitélio Pigmentado da Retina/patologia , Ultrassom , Adulto , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Corantes/metabolismo , Dextranos/metabolismo , Células Epiteliais/efeitos dos fármacos , Fluoresceína-5-Isotiocianato/análogos & derivados , Fluoresceína-5-Isotiocianato/metabolismo , Glucose/toxicidade , Humanos , L-Lactato Desidrogenase/metabolismo , NF-kappa B/metabolismo , Transporte Proteico/efeitos dos fármacos , Temperatura , Proteína da Zônula de Oclusão-1/metabolismo
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