Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 103
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
EMBO J ; 39(13): e103630, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32449547

RESUMO

Light and temperature are two core environmental factors that coordinately regulate plant growth and survival throughout their entire life cycle. However, the mechanisms integrating light and temperature signaling pathways in plants remain poorly understood. Here, we report that CBF1, an AP2/ERF-family transcription factor essential for plant cold acclimation, promotes hypocotyl growth under ambient temperatures in Arabidopsis. We show that CBF1 increases the protein abundance of PIF4 and PIF5, two phytochrome-interacting bHLH-family transcription factors that play pivotal roles in modulating plant growth and development, by directly binding to their promoters to induce their gene expression, and by inhibiting their interaction with phyB in the light. Moreover, our data demonstrate that CBF1 promotes PIF4/PIF5 protein accumulation and hypocotyl growth at both 22°C and 17°C, but not at 4°C, with a more prominent role at 17°C than at 22°C. Together, our study reveals that CBF1 integrates light and temperature control of hypocotyl growth by promoting PIF4 and PIF5 protein abundance in the light, thus providing insights into the integration mechanisms of light and temperature signaling pathways in plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Hipocótilo/crescimento & desenvolvimento , Temperatura , Transativadores/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Hipocótilo/genética , Transativadores/genética
2.
Small ; : e2400041, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38497487

RESUMO

Triboelectric Nanogenerator (TENG) has proven highly effective in converting mechanical energy into electrical energy. Previous research on manipulating microstructure for performance enhancement primarily focused on the surface of TENGs. In this study, an innovative bottom-up strategic design to control the internal nano-architecture for the enhanced output of TENG is proposed. This multiscale structural design strategy consists of defect chemistry (angstrom-scale), surface modification (nano-scale), and spatial regulation of nanoparticles (meso-scale), which helps explore the optimal utilization of TENG's internal structure. After fine-tuning the nano-architecture, the output voltage is significantly increased. This optimized TENG serves as a robust platform for developing self-powered systems, including self-powered electrochemical chlorination systems for sterilization. Additionally, through the utilization of multiscale simulations (density functional theory, all-atom molecular dynamics, and dissipative particle dynamics), the underlying mechanisms governing how the optimized nanoparticle-polymer interface and spatial arrangement of nanoparticles influence the storage and transfer of charges are comprehensively elucidated. This study not only demonstrates the effectiveness of manipulating internal nano-architecture to enhance TENG performance for practical applications but also provides invaluable insights into structural engineering for TENG advancement.

3.
PLoS Pathog ; 18(8): e1010744, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35914008

RESUMO

Kaposi's sarcoma-associated herpesvirus (KSHV) is a double-stranded DNA virus with the capacity to establish life-long latent infection. During latent infection, the viral genome persists as a circular episome that associates with cellular histones and exists as a nonintegrated minichromosome in the nucleus of infected cells. Chromatin structure and epigenetic programming are required for the proper control of viral gene expression and stable maintenance of viral DNA. However, there is still limited knowledge regarding how the host regulates the chromatin structure and maintenance of episomal DNA. Here, we found that the cellular protein structural maintenance of chromosome (SMC) complex SMC5/6 recognizes and associates with the KSHV genome to inhibit its replication. The SMC5/6 complex can bind to the KSHV genome and suppress KSHV gene transcription by condensing the viral chromatin and creating a repressive chromatin structure. Correspondingly, KSHV employs an antagonistic strategy by utilizing the viral protein RTA to degrade the SMC5/6 complex and antagonize the inhibitory effect of this complex on viral gene transcription. Interestingly, this antagonistic mechanism of RTA is evolutionarily conserved among γ-herpesviruses. Our work suggests that the SMC5/6 complex is a new host factor that restricts KSHV replication.


Assuntos
Herpesvirus Humano 8 , Proteínas Imediatamente Precoces , Infecção Latente , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/genética , Regulação Viral da Expressão Gênica , Herpesvirus Humano 8/fisiologia , Humanos , Proteínas Imediatamente Precoces/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Transativadores , Ubiquitina/metabolismo , Latência Viral/genética , Replicação Viral/genética
4.
Plant Cell ; 32(7): 2196-2215, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32371543

RESUMO

Phytochromes are red (R) and far-red (FR) light photoreceptors in plants, and PHYTOCHROME-INTERACTING FACTORS (PIFs) are a group of basic helix-loop-helix family transcription factors that play central roles in repressing photomorphogenesis. Here, we report that MYB30, an R2R3-MYB family transcription factor, acts as a negative regulator of photomorphogenesis in Arabidopsis (Arabidopsis thaliana). We show that MYB30 preferentially interacts with the Pfr (active) forms of the phytochrome A (phyA) and phytochrome B (phyB) holoproteins and that MYB30 levels are induced by phyA and phyB in the light. It was previously shown that phytochromes induce rapid phosphorylation and degradation of PIFs upon R light exposure. Our current data indicate that MYB30 promotes PIF4 and PIF5 protein reaccumulation under prolonged R light irradiation by directly binding to their promoters to induce their expression and by inhibiting the interaction of PIF4 and PIF5 with the Pfr form of phyB. In addition, our data indicate that MYB30 interacts with PIFs and that they act additively to repress photomorphogenesis. In summary, our study demonstrates that MYB30 negatively regulates Arabidopsis photomorphogenic development by acting to promote PIF4 and PIF5 protein accumulation under prolonged R light irradiation, thus providing new insights into the complicated but delicate control of PIFs in the responses of plants to their dynamic light environment.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Regulação da Expressão Gênica de Plantas , Luz , Fitocromo A/metabolismo , Fitocromo B/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Plântula/fisiologia , Fatores de Transcrição/genética
5.
Anal Biochem ; 663: 115021, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36539047

RESUMO

ATP is a high-energy compound that plays a vital role in biological metabolism. Abnormal changes in ATP concentration are related to various diseases and reflect microbial metabolism in biofilms. In this work, we prepared carbon quantum dots (CDs) with aggregation-induced fluorescence inhibition effect using the bacterial culture medium as raw material with a hydrothermal method. Then, an abiotic fluorescent nanoprobe named CDs@zeolitic imidazolate frameworks-90 (ZIF-90) was facilely synthesized by encapsulating CDs into ZIF-90. Owing to the encapsulation of CDs in the hollow structure of ZIF-90, the blue fluorescence emission of CDs@ZIF-90 decreased significantly. In the presence of ATP, the ZIF-90 framework was destroyed due to the strong coordination between ATP and Zn2+. The released CDs exhibited stronger fluorescence intensity, which was closely related to the ATP concentration. The convenient synthesis process and rapid ATP-responsive ability make CDs@ZIF-90 highly promising for clinical and environmental analysis.


Assuntos
Pontos Quânticos , Zeolitas , Trifosfato de Adenosina/análise , Corantes Fluorescentes/química , Carbono/química , Pontos Quânticos/química
6.
Mikrochim Acta ; 190(12): 475, 2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-37991569

RESUMO

A surface-enhanced Raman scattering nanoprobe has been developed for sulfide detection and applied to  complex bacterial biofilms. The nanoprobe, Au@4-MBN@Ag@ZIF-8, comprised a gold core modified with 4-mercaptobenzonitrile (4-MBN) as signaling source, a layer of silver shell as the sulfide sensitization material, and a zeolitic imidazolate framework-8 (ZIF-8) as surface barrier. ZIF-8, with its high surface area and mesoporous structure, was applied to preconcentrate sulfide around the nanoprobe with its excellent adsorption capacity. Besides, the external wrapping of ZIF-8 can not only prevent the interference of biomolecules, such as proteins, with the Au@4-MBN@Ag assay but also enhance the detection specificity through the sulfide cleavage function towards ZIF-8. These properties are critical for the application of this nanoprobe to complex environmental scenarios. In the presence of sulfide, it was first enriched through adsorption by the outer ZIF-8 layer, then destroyed the barrier layer, and subsequently reacted with the Ag shell, leading to changes in the Raman signal. Through this rational design, the Au@4-MBN@Ag@ZIF-8 nanoprobe exhibited excellent detection sensitivity, with a sulfide detection limit in the nanomolar range and strong linearity in the concentration range  50 nM to 500 µM. Furthermore, the proposed Au@4-MBN@Ag@ZIF-8 nanoprobe was effectively utilized for sulfide detection in intricate biofilm matrices, demonstrating its robust selectivity and reproducibility.


Assuntos
Nanopartículas Metálicas , Zeolitas , Matriz Extracelular de Substâncias Poliméricas , Ouro , Reprodutibilidade dos Testes , Prata , Análise Espectral Raman , Sulfetos
7.
Mikrochim Acta ; 191(1): 17, 2023 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-38087067

RESUMO

A direct and ultra-sensitive surface-enhanced Raman scattering (SERS) immunoassay method is introduced for the detection of Escherichia coli and Staphylococcus aureus. This methodology is based on a sandwich-structured complex probe (SCP) mechanism, combined with target-induced strand displacement. Moreover, by leveraging the amplified SERS signal from gold nanoparticles (AuNPs) corresponding to an increase in bacterial count, we achieve quantitative determination. The SCP demonstrates remarkable specificity, sensitivity, and anti-interference capability in bacterial detection. The detection limits for both bacterial strains are as low as 10 CFU/mL. In our selectivity tests, all peak intensities had standard deviations (n = 3) below 6%. Recoveries in normal human serum were 101-110% for E. coli and 96-101% for S. aureus. In milk, the recoveries were 102-105% for E. coli and 100-105% for S. aureus, respectively, demonstrating a high level of accuracy and resistance to interference. In addition, the SCP offers a dual-detection capability, enabling simultaneous diagnosis of multiple targets, which greatly simplifies the testing procedure. The findings underscore that this immunoassay platform fulfills the demand for rapid and precise pathogenic bacterial diagnosis, holding substantial potential for practical applications.


Assuntos
Nanopartículas Metálicas , Staphylococcus aureus , Humanos , Escherichia coli , Ouro , Bactérias , Imunoensaio/métodos
8.
Int J Mol Sci ; 24(6)2023 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-36982474

RESUMO

Many marine invertebrates have planktonic larval and benthic juvenile/adult stages. When the planktonic larvae are fully developed, they must find a favorable site to settle and metamorphose into benthic juveniles. This transition from a planktonic to a benthic mode of life is a complex behavioral process involving substrate searching and exploration. Although the mechanosensitive receptor in the tactile sensor has been implicated in sensing and responding to surfaces of the substrates, few have been unambiguously identified. Recently, we identified that the mechanosensitive transient receptor potential melastatin-subfamily member 7 (TRPM7) channel, highly expressed in the larval foot of the mussel Mytilospsis sallei, was involved in substrate exploration for settlement. Here, we show that the TRPM7-mediated Ca2+ signal was involved in triggering the larval settlement of M. sallei through the calmodulin-dependent protein kinase kinase ß/AMP-activated protein kinase/silk gland factor 1 (CaMKKß-AMPK-SGF1) pathway. It was found that M. sallei larvae preferred the stiff surfaces for settlement, on which TRPM7, CaMKKß, AMPK, and SGF1 were highly expressed. These findings will help us to better understand the molecular mechanisms of larval settlement in marine invertebrates, and will provide insights into the potential targets for developing environmentally friendly antifouling coatings for fouling organisms.


Assuntos
Bivalves , Canais de Cátion TRPM , Animais , Proteínas Quinases Ativadas por AMP/metabolismo , Organismos Aquáticos/metabolismo , Bivalves/fisiologia , Quinase da Proteína Quinase Dependente de Cálcio-Calmodulina/metabolismo , Larva/metabolismo , Fosforilação , Canais de Cátion TRPM/metabolismo , Cálcio/metabolismo , Transdução de Sinais
9.
Mikrochim Acta ; 189(11): 403, 2022 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-36197586

RESUMO

A multi pathogenic microorganisms determination method is reported using DNA composites encapsulated DNA silver nanocluster (AgNCs)/graphene oxide (GO)-based system through rolling cycle (RCA) amplification. Firstly, two different RCA-based DNA composites are assembled, coupled with thousands of DNA-stabilized AgNCs probe and ssDNA aptamer specific for two pathogen bacteria targets. GO was then introduced into the system to capture ssDNA aptamer of DNA composites and as a selective fluorescence quencher of DNA/AgNCs. Upon recognizing the target bacteria, ssDNA aptamer part would combine with bacteria and release from the surface of GO. Thus, DNA/AgNCs of RCA-based DNA composites can generate strong fluorescence signal. With the fluorescent report of RCADNA-AgNCs/530 and RCADNA-AgNCs/625, the assay successfully detect Escherichia coli and Staphylococcus aureus at concentrations as low as 38 CFU/mL, and a highly selective and efficient sensing platform was achieved. Therefore, this RCA/DNA-AgNCs/GO-based platform shows excellent application in multi pathogenic microorganisms determination and potential clinic therapy.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , DNA/genética , DNA de Cadeia Simples , Grafite , Óxidos , Prata , Compostos de Prata , Espectrometria de Fluorescência
10.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 53(3): 538-542, 2022 May.
Artigo em Zh | MEDLINE | ID: mdl-35642168

RESUMO

High-sugar diet causes various diseases, including insulin resistance, diabetes, and non-alcoholic fatty liver disease (NAFLD). In recent years, as researchers probe deeper and deeper into issues concerning high-sugar diet, the impact of high-sugar diet on inflammatory diseases such as autoimmune diseases and infectious diseases has been gradually uncovered and clarified. In this review, we summarized the current research progress on high-sugar diet and inflammatory diseases, and suggested that a high-sugar diet based on high intake of glucose and fructose may be an important factor inducing the exacerbation of chronic inflammatory diseases such as autoimmune diseases. Moreover, we also summarized the regulatory mechanisms through which high-sugar diet induces exacerbation of inflammatory diseases. In addition, we stated that conducting extensive clinical research and research in real-life settings and pursuing thorough investigation to reveal the different involvement of high-glucose diet and high-fructose diet in immune regulation are the key scientific issues that need urgent solutions in the future.


Assuntos
Doenças Autoimunes , Hepatopatia Gordurosa não Alcoólica , Doenças Autoimunes/complicações , Dieta/efeitos adversos , Frutose/efeitos adversos , Glucose , Humanos , Hepatopatia Gordurosa não Alcoólica/etiologia
11.
World J Microbiol Biotechnol ; 37(7): 124, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34170406

RESUMO

Sulfate-reducing bacteria (SRB) are culprits for microbiologically influenced corrosion, and biofilms are believed to play essential roles in the corrosion induced by SRB. However, little is known about the regulation of SRB biofilms. Quorum sensing signal molecules acyl-homoserine lactones (AHLs) and autoinducer-2 (AI-2) regulate biofilm formation of many bacteria. In this study, the production of AHLs and AI-2 by one SRB strain, Desulfovibrio sp. Huiquan2017, was detected, and the effect of exogenous AI-2 on bacterial biofilm formation was discussed. It was found that the cell-free supernatants of Desulfovibrio sp. Huiquan2017 induced luminescence in a ∆luxS mutant strain Vibrio harveyi BB170, indicating the production of functional AI-2 by the bacterium. In the presence of exogenous AI-2, the growth of Desulfovibrio sp. Huiquan2017 and early biofilm formation were not affected, but the later stage of biofilm development was inhibited significantly. The biofilms became looser, smaller, and thinner, and contained less bacteria and extracellular polymeric substances (EPS). The inhibition effect of AI-2 on the biofilm development of Desulfovibrio sp. Huiquan2017 was mainly achieved through reducing the amount of EPS in biofilms. These findings shed light on the biofilm regulation of SRB.


Assuntos
Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Desulfovibrio/efeitos dos fármacos , Desulfovibrio/crescimento & desenvolvimento , Desulfovibrio/metabolismo , Homosserina/análogos & derivados , Lactonas/metabolismo , Lactonas/farmacologia , Agrobacterium tumefaciens/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/farmacologia , Corrosão , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Homosserina/metabolismo , Homosserina/farmacologia , Percepção de Quorum , Vibrio/metabolismo
13.
Anal Biochem ; 600: 113764, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32360199

RESUMO

In this paper, we present a facile and rapid multichannel approach for the simultaneous detection and discrimination of multiple bacterial species. The proposed assay employed four short antimicrobial peptides (SAMPs) for recognition due to their disparity in antibacterial activity against different bacterial strains, and utilized fluorescence measurements to explicate the bacterial recognition and disintegration disparity of the SAMPs. Then, linear discriminant analysis (LDA) was used to effectively discriminate and classify the observed characteristic fluorescence patterns of SAMPs towards target bacteria, exhibiting excellent bacterial discrimination and classification accuracy. This is the first report on the use of SAMPs as recognition units for simultaneous multiple bacterial detection and discrimination. The presented approach was simple, fast, highly repeatable, and required no labelling processes. According to the corresponding LDA discriminant results, six different target bacterial species could be effectively identified and discriminated within 30 min.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Bacillus subtilis/efeitos dos fármacos , Análise Discriminante , Escherichia coli/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus/efeitos dos fármacos
14.
Anal Bioanal Chem ; 411(10): 2161-2168, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30859270

RESUMO

Here we report a bacteria detection method based on a flow cytometric bead system and 16S rRNA-targeted oligonucleotide probes. Polymerase chain reaction (PCR) was first used to acquire bacterial DNA including bacteria-specific sequences. Half of the resulting target DNA was then captured by a capture probe immobilized on a magnetic microbead (MB) surface. The other half of the target DNA was hybridized with a fluorescence-labeled signal probe. In this manner, a sandwich DNA hybridization involving a MB-based capture probe, the target DNA, and a signal probe was realized. The MB carriers modified with reporter dye were analyzed one by one by flow cytometry through a capillary. Using PCR amplicons and this flow cytometric bead system, a detection limit of 180 cfu mL-1 was achieved, along with high selectivity that permitted the discrimination of different targets when challenged with control bacteria targets and multiplexing capabilities that enabled the simultaneous detection of two kinds of bacteria. Given these advantages, the developed method can be used for the highly sensitive and specific PCR amplicon analysis of DNA extracted from a fresh bacterial culture, as well as multiplex target analysis. Graphical abstract The flow cytometric bead system with 16S rRNA-targeted oligonucleotide probes for bacteria detection developed in this work. This system is highly specific and sensitive, with a detection limit of 180 cfu mL-1 bacteria.


Assuntos
Bactérias/isolamento & purificação , DNA Bacteriano/análise , Citometria de Fluxo/métodos , Sondas de Oligonucleotídeos/química , RNA Ribossômico 16S/química , Infecções Bacterianas/microbiologia , Carga Bacteriana/métodos , Humanos , Hibridização de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase/métodos
15.
Mikrochim Acta ; 186(12): 784, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31732809

RESUMO

It is demonstrated that vanadium tetrasulfide (VS4) exhibits peroxidase (POx)-like activity which follows Michaelis-Menten kinetics when using H2O2 as a co-substrate. Electron spin resonance spectroscopy was use to analyze the catalytic mechanism. It suggests that the enzyme mimicking activity is caused by decomposing H2O2 into hydroxyl radicals. The method was used to quantify H2O2 by using 3,3',5,5'-tetramethylbenzidine as the substrate which results in the formation of a blue coloration (with an absorption peak at 652 nm). H2O2 can be detected in the 50 to 300 µM concentration range, and the detection limit is 5.0 µM. The assay for L-cysteine (L-cys) is based on the capability of oxTMB to oxidize L-cys to form L-cystine. The colorimetric L-cys assay has a linear response in the 5 to 100 µM concentration range and a 2.5 µM detection limit. Graphical abstractSchematic representation of the enzyme mimicking activity of vanadium tetrasulfide (VS4) submicrospheres originated from the decomposition of hydrogen peroxide (H2O2) to generate reactive hydroxyl radical (·OH) and the colorimetric detection of L-cysteine.


Assuntos
Cisteína/análise , Peróxido de Hidrogênio/análise , Microesferas , Compostos de Vanádio/química , Benzidinas/química , Catálise , Colorimetria/métodos , Corantes/química , Cisteína/química , Peróxido de Hidrogênio/química , Cinética , Limite de Detecção , Oxirredução , Peroxidase/química
16.
Mikrochim Acta ; 186(6): 382, 2019 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-31134381

RESUMO

It is reported that gold(I)-thiolate complexes can display aggregation-induced emission (AIE) similar to organic fluorogens. On addition of lead(II) to glutathione-gold(I) complexes, a supermolecular structure of type GSH-Au(I)-Pb(II) is formed through strong coordination between Pb(II) and GSH. Its fluorescence is quenched by sulfide due to the formation of PbS which destroys the GSH-Au(I)-Pb(II) complex. The finding was used to design a method for fluorometric detection of sulfate-reducing bacteria (SRB) which produce sulfide. The time needed to reduce fluorescence to 10% of its initial intensity linearly dependent on the logarithm of the SRB concentrations in the ranging from 10 to 1 × 10^7 cfu mL-1. The assay time is also reduced down to 4 days even if the SRB concentration is as low as 10 cfu mL-1. Graphical abstract Schematic presentation of aggregation-induced emission (AIE)-active GSH-Au(I) complexes based fluorescence detection of SRB. The GSH-Au(I) complexes turn into aggregation and display strong emissive property in the presence of Pb2+. Then the fluorescence of GSH-Au(I)-Pb(II) complexes can be quenched by S2- generated by SRB.


Assuntos
Bactérias/isolamento & purificação , Bactérias/metabolismo , Complexos de Coordenação/química , Fluorometria , Glutationa/química , Ouro/química , Sulfatos/metabolismo , Escherichia coli/isolamento & purificação , Fluorescência , Chumbo/química , Listeria monocytogenes/isolamento & purificação , Pseudomonas aeruginosa/isolamento & purificação , Staphylococcus/isolamento & purificação , Staphylococcus aureus/isolamento & purificação
17.
Mikrochim Acta ; 185(1): 1, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-29594366

RESUMO

Single phase metastable α-AgVO3 microrods with high crystallinity, tetragonal rod-like microstructure, uniform particle size distribution, and good dispersion were synthesized by direct coprecipitation at room temperature. They are shown to be viable peroxidase mimics that catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine in the presence of H2O2. Kinetic analysis indicated typical Michaelis-Menten catalytic behavior. The findings were used to design a colorimetric assay for H2O2, best measured at 652 nm. The method has a linear response in the 60 to 200 µM H2O2 concentration range, with a 2 µM detection limit. Benefitting from the chemical stability of the microrods, the method is well reproducible. It also is easily performed and highly specific. Graphic abstract Single phase metastable α-AgVO3 microrods with high crystallinity, tetragonal rod-like microstructure, uniform particle size distribution, and good dispersion can efficiently catalyze the oxidation reaction of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue color change.

18.
Indian J Microbiol ; 57(3): 344-350, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28904420

RESUMO

Sulfate-reducing bacteria (SRB) were found to be capable of tolerating a certain amount of oxygen (O2), but how they affect oxygen reduction reaction (ORR) has not been clear. The present work investigated the impact of SRB on ORR in 3.5 wt% sodium chloride solution with the cyclic voltammetry method. The addition of SRB culture solution hampered both the reduction of O2 to superoxide (O2·-) and hydrogen peroxide (H2O2) to water (H2O), and the influence of SRB metabolites was much larger than that of bacterial cells. Sulfide and extracellular polymeric substances (EPS), typical inorganic and organic metabolic products, had great impact on ORR. Sulfide played an important role in the decrease of cathodic current for H2O2 reduction due to its hydrolysis and chemical reaction activity with H2O2. EPS were sticky, easy to adsorb on the electrode surface and abundant in functional groups, which hindered the transformation of O2 into O2·- and favored the reduction of H2O2 to H2O.

19.
Chemistry ; 2015 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-26130083

RESUMO

Bi5 O7 I nanobelts were prepared by a facile hydrothermal method to study the crystal phase transformation and morphology evolution. Based on these results, a crystal growth mechanism of Bi5 O7 I nanobelts was proposed. To enhance the photocatalytic antifouling activity, ethanol or TiCl3 was used to modify the Bi5 O7 I nanobelts. The resulting BiOI/Bi2 O2 CO3 /Bi5 O7 I and TiO2 /BiOCl/Bi5 O7 I micro-nanostructures show excellent degradation activity of malachite green and bactericidal effects against Pseudomonas aeruginosa, which may be attributed to the higher charge carrier separation efficiency of these heterojunction structures. The results indicate that the formation of semiconductor composites is a very effective strategy to design high-performance photocatalyst systems.

20.
Environ Sci Pollut Res Int ; 31(3): 3628-3640, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38085474

RESUMO

The corrosion of marine engineering equipment not only threatens human security and ecological environment but also increases energy consumption, restricting the sustainable development of marine economies and industries. The tidal region is a complex and challenging environment that can cause severe corrosion of facilities and affect microbial activities. However, the current understanding of the mechanisms underlying microbiologically influenced corrosion (MIC) of tidal region is insufficient. To address this issue, the effect of Pseudomonas aeruginosa on a Cu-Zn-Ni alloy in the simulative tidal region was investigated by chemical and molecular biological analysis in this study. The results demonstrated that P. aeruginosa formed thicker biofilms on the Cu-Zn-Ni alloy samples under the full exposure, accelerating corrosion compared to sterile controls. Interestingly, the corrosion of P. aeruginosa toward the Cu-Zn-Ni alloy was inhibited in the simulative tidal region. This inhibition behavior was relevant to the reduction in the quantity of sessile cells and cell activities. The expression down-regulation of genes encoding phenazines induced the decrease in electron transfer mediators and weakened the MIC of P. aeruginosa on alloy samples in the simulative tidal region. The research sheds light on the characteristics of P. aeruginosa and corrosion products on the Cu-Zn-Ni alloy, as well as their interaction mechanisms underlying corrosion in the simulative tidal region. The study will facilitate the evaluation and control of MIC in the tidal region, contributing to the development of sustainable strategies for preserving the integrity and safety of marine facilities.


Assuntos
Ligas , Pseudomonas aeruginosa , Humanos , Pseudomonas aeruginosa/metabolismo , Ligas/química , Corrosão , Biofilmes , Zinco/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA