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1.
Nano Lett ; 24(25): 7732-7740, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38869233

RESUMO

Rechargeable lithium-ion batteries are integral to contemporary energy storage, yet current anode material systems struggle to meet the increasing demand for extended range capabilities. This work introduces a novel composite anode material composed of one-dimensional 2H-phase tin disulfide (SnS2) nanoribbons enclosed within cavities of single-walled carbon nanotubes (SnS2@SWCNTs), achieved through precise atomic engineering. Employing aberration-corrected transmission electron microscopy, we precisely elucidated the crystal structure of SnS2 within the confines of the SWCNTs. This deliberate design effectively addresses the inherent limitations of SnS2 as a lithium-ion anode material, including its low electrical conductivity, considerable volume expansion effects, and unstable solid electrolyte interface membrane. Testing confirmed that SnS2 transforms into the Li5Sn2 alloy phase after full lithiation and back to SnS2 after delithiation, showing excellent reversibility. The composite also benefits from edge effects, improving lithium storage through stronger binding and lower migration barriers, which were supported by calculations. This pioneering work advances high-performance anode materials for applications.

2.
Biodegradation ; 33(3): 223-237, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35419646

RESUMO

Efficient biodegradation may offer a solution for the treatment of nitro-aromatic compounds (NACs) with toxicity, mutagenicity and persistence in the environment. In this study, dopamine (DA) functionalized magnetic nanoparticles with biocompatibility and hydrophilicity were synthesized and utilized for the immobilization of nitro-aromatic compounds degrading psychrophile Psychrobacter sp. ANT206 harboring the cold-adapted nitroreductase. The prepared nanocarriers were characterized using multiple methods. The highest immobilization yield of cells immobilized by Fe3O4@SiO2@DA was 90.67% under the optimized conditions of 10 °C, pH 7.5, 2 h and cell/support 1.2 mg/mg, and the activity recovery was 89.41%. In addition, the obtained immobilized cells displayed excellent salinity stability and reusability. Moreover, immobilized P. sp. ANT206 strains showed remarkable biodegradation capability on nitrobenzene and p-nitrophenol. This study introduced those novel Fe3O4@SiO2@DA nanoparticles could be applied as ideal and low-cost nanocarriers for the immobilization of cells and large-scale bioremediation of hazardous NACs with perspective applications under low temperature.


Assuntos
Nanopartículas de Magnetita , Psychrobacter , Biodegradação Ambiental , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Nanopartículas de Magnetita/química , Nitrocompostos , Dióxido de Silício/química , Temperatura
3.
J Basic Microbiol ; 62(8): 984-994, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35762735

RESUMO

Serine hydroxymethyltransferase (SHMT) plays a significant role in the synthesis of l-serine, purine, and thymidylate, which could be extensively applied in the treatment of cancers and the development of antibiotics. In this study, cloned from Psychrobacter sp. ANT206, a novel cold-adapted SHMT gene (psshmt, 1257 bp) encoding a protein of 418 amino acids was expressed in Escherichia coli. The homology modeling result revealed that PsSHMT owned fewer Proline (Pro) residues and hydrogen bonds compared with its homologs from mesophilic E. coli and thermophilic Geobacillus stearothermophilus. In addition, the molecular weight of the purified recombinant PsSHMT (rPsSHMT) was identified to be 45 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, approximately. The enzymatic characteristics of the cold-adapted rPsSHMT displayed that its optimum temperature and pH were 30°C and 7.5, respectively, and its enzymatic activity could be inhibited by Cu2+ , significantly. rPsSHMT also showed a high kcat value and low ΔG at low temperatures. Furthermore, arginine (Arg) could affect the activity of rPsSHMT and be vital to its active sites. The results of this study reflected that these characteristics of the cold-adapted rPsSHMT made it a remarkable candidate that could be utilized in multiple industrial fields under low temperatures.


Assuntos
Psychrobacter , Clonagem Molecular , Temperatura Baixa , Escherichia coli/genética , Glicina Hidroximetiltransferase/genética , Psychrobacter/genética
4.
Int J Mol Sci ; 23(3)2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35163237

RESUMO

Glutaredoxin (Grx) is an important oxidoreductase to maintain the redox homoeostasis of cells. In our previous study, cold-adapted Grx from Psychrobacter sp. ANT206 (PsGrx) has been characterized. Here, we constructed an in-frame deletion mutant of psgrx (Δpsgrx). Mutant Δpsgrx was more sensitive to low temperature, demonstrating that psgrx was conducive to the growth of ANT206. Mutant Δpsgrx also had more malondialdehyde (MDA) and protein carbonylation content, suggesting that PsGrx could play a part in the regulation of tolerance against low temperature. A yeast two-hybrid system was adopted to screen interacting proteins of 26 components. Furthermore, two target proteins, glutathione reductase (GR) and alkyl hydroperoxide reductase subunit C (AhpC), were regulated by PsGrx under low temperature, and the interactions were confirmed via bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation (Co-IP). Moreover, PsGrx could enhance GR activity. trxR expression in Δpsgrx, Δahpc, and ANT206 were illustrated 3.7, 2.4, and 10-fold more than mutant Δpsgrx Δahpc, indicating that PsGrx might increase the expression of trxR by interacting with AhpC. In conclusion, PsGrx may participate in glutathione metabolism and ROS-scavenging by regulating GR and AhpC to protect the growth of ANT206. These findings preliminarily suggest the role of PsGrx in the regulation of oxidative stress, which could improve the low-temperature tolerance of ANT206.


Assuntos
Glutarredoxinas/metabolismo , Psychrobacter/genética , Sequência de Aminoácidos , Antioxidantes/metabolismo , Temperatura Baixa , Glutarredoxinas/fisiologia , Glutationa Redutase/metabolismo , Glutationa Redutase/fisiologia , Homeostase , Cinética , Modelos Moleculares , Oxirredução , Estresse Oxidativo , Peroxirredoxinas/metabolismo , Peroxirredoxinas/fisiologia , Psychrobacter/metabolismo , Temperatura
5.
Phys Chem Chem Phys ; 23(6): 3898-3904, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33543205

RESUMO

Due to the low cost, high element abundance and intrinsic safety, potassium-ion batteries (KIBs) have attracted a surge of interest in recent years. Currently, the key challenge and obstacle to the development of KIBs is to find suitable anode materials with large capacity, high rate capability and small lattice changes during the charge/discharge process. MXenes with excellent energy storage properties are promising anode materials for KIBs and their energy performance largely depends on the surface termination. Here, two-dimensional O- and S-terminated V2C MXene anode materials are designed to model high performance potassium-ion batteries. Using first-principles calculations, the structural properties and potential battery performance in KIBs of V2CO2 and V2CS2 are systematically investigated. The inherent metallic nature, a small diffusion barrier, a low average open circuit voltage, and a high theoretical specific capacity (489.93 mA h g-1 of V2CO2 and 200.24 mA h g-1 of V2CS2) demonstrate that both of them are ideal anode materials for KIBs. Meanwhile, we also investigated the mechanism of the difference in energy performance between V2CO2 and V2CS2 at atomic and electronic levels, in other words, the energy performance difference introduced by surface O- and S-terminations.

6.
Protein Expr Purif ; 173: 105661, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32387145

RESUMO

A novel superoxide dismutase (referred hereafter to as HsSOD) from the psychrophilic bacterium Halomonas sp. ANT108 was purified and characterized. Escherichia coli (E. coli) was selected as the expression host. After recombinant HsSOD (rHsSOD) was purified, the specific activity was determined to be 213.47 U/mg with a purification ratio of approximately 3.61-fold. SDS-PAGE results demonstrated that rHsSOD has the molecular weight of 31.3 kDa, and type identification revealed that it belongs to Cu/Zn SOD. The optimum activity of rHsSOD was at 35 °C and 28% of its maximum activity remained at 0 °C. Further enzymatic assays indicated that rHsSOD exhibited thermal instability with a half-life of 20 min at 60 °C. Moreover, Cu2+ and Zn2+ significantly promoted rHsSOD activity. The values of Km and Vmax were 0.33 mM and 476.19 U/mg, respectively. Interestingly, rHsSOD could avoid DNA strand breakage formed by metal-catalyzed oxidation, demonstrating its antioxidant capacity. To summarize, the results suggested that rHsSOD has relatively high catalytic efficiency and oxidation resistance at low temperatures.


Assuntos
Proteínas de Bactérias , Dano ao DNA , DNA/química , Halomonas/genética , Superóxido Dismutase , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Escherichia coli/genética , Escherichia coli/metabolismo , Halomonas/enzimologia , Oxirredução , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Superóxido Dismutase/química , Superóxido Dismutase/genética , Superóxido Dismutase/isolamento & purificação
7.
Phys Chem Chem Phys ; 22(39): 22236-22243, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33000818

RESUMO

The lack of high-performance anode materials has become a major obstacle to the development of Li- and Na-ion batteries. Recently, 2D transition metal borides (e.g. MBenes) have attracted much attention due to their excellent stability and electrical conductivity. Unfortunately, most of the reported MBene phases typically have an intrinsic metal-rich structure with metal atoms exposed on the surface, which harmfully affect the adsorption of Li/Na atoms. Here, through crystal structure prediction combined with the first-principles density functional theory, a novel TiB3 MBene has been determined by altering the proportion of non-metallic element boron to wrap metal atoms and weaken nearest-neighbor electrostatic repulsion. Electrostatic potential analysis visually shows a surface with low potential on the TiB3 monolayer implying high adsorption capacity, and also can be used to quickly screen out the Li/Na adsorption sites. Accurate half-cell battery simulation confirmably shows that the TiB3 monolayer possesses a theoretical specific capacity of 1335.04 and 667.52 mA h g-1 for Li and Na, respectively. The TiB3 monolayer can remain metallic after adsorbing Li/Na atoms, which ensures good conductivity during battery cycling. The ultra-low barrier energy (only 38 meV for Li) and suitable open-circuit voltage indicate excellent charging and discharging capabilities. These results suggest that the TiB3 monolayer could be a promising anode material for Li- and Na-ion batteries, and provide a simple design principle for exposing non-metallic atoms on the surface.

8.
Int J Mol Sci ; 21(2)2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31936518

RESUMO

A new glutathione reductase gene (psgr) coding for glutathione reductase (GR) from an Antarctic bacterium was cloned and overexpressed into Escherichia coli (E. coli). A sequence analysis revealed that PsGR is a protein consisting of 451 amino acids, and homology modeling demonstrated that PsGR has fewer hydrogen bonds and salt bridges, which might lead to improved conformational flexibility at low temperatures. PsGR possesses the flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide phosphate (NADPH) binding motifs. Recombinant PsGR (rPsGR) was purified using Ni-NTA affinity chromatography and was found to have a molecular mass of approximately 53.5 kDa. rPsGR was found to be optimally active at 25 °C and a pH of 7.5. It was found to be a cold-adapted enzyme, with approximately 42% of its optimal activity remaining at 0 °C. Moreover, rPsGR was most active in 1.0 M NaCl and 62.5% of its full activity remained in 3.0 M NaCl, demonstrating its high salt tolerance. Furthermore, rPsGR was found to have a higher substrate affinity for NADPH than for GSSG (oxidized glutathione). rPsGR provided protection against peroxide (H2O2)-induced oxidative stress in recombinant cells, and displayed potential application as an antioxidant protein. The results of the present study provide a sound basis for the study of the structural characteristics and catalytic characterization of cold-adapted GR.


Assuntos
Adaptação Fisiológica , Temperatura Baixa , Glutationa Redutase/metabolismo , Psychrobacter/enzimologia , Tolerância ao Sal , Sequência de Aminoácidos , Bioensaio , Genes Bacterianos , Glutationa Redutase/química , Glutationa Redutase/isolamento & purificação , Cinética , Testes de Sensibilidade Microbiana , Modelos Moleculares , Oxirredução , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Homologia Estrutural de Proteína , Termodinâmica
9.
Biochem Biophys Res Commun ; 509(3): 746-752, 2019 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-30621914

RESUMO

MicroRNA-501-3p (miR-501-3p) has been reported as a novel cancer-related miRNA in many types of cancer. However, the precise biological function of miR-501-3p in prostate cancer remains unknown. In this study, we aimed to investigate the regulatory effect and mechanism of miR-501-3p on cell growth of prostate cancer cells. We found that miR-501-3p expression was significantly downregulated in prostate cancer tissues and cell lines. Gain-of-function experiments showed that upregulation of miR-501-3p expression significantly decreased cell proliferation and colony formation, and induced cell cycle arrest in the G0/G1 phase. Bioinformatics analysis predicted that cell cycle-related and expression-elevated protein in tumor (CREPT) was a potential target gene of miR-501-3p., and the results of our luciferase reporter assay confirmed that miR-501-3p bound to the 3'-untranslated region of CREPT at the predicted binding site. Moreover, miR-501-3p was shown to negatively regulate CREPT expression in prostate cancer cells. Correlation analysis showed that miR-501-3p was inversely correlated with CREPT expression in prostate cancer tissues. Knockdown studies revealed that miR-501-3p regulated the expression of cyclin D1 by targeting CREPT. Additionally, the inhibitory effect of miR-501-3p on prostate cancer cell growth was partially reversed by CREPT overexpression. Overall, these results suggest that miR-501-3p restricts prostate cancer cell growth by targeting CREPT to inhibit the expression of cyclin D1. These findings indicate that the miR-501-3p/CREPT/cyclin D1 axis plays a crucial role in the progression of prostate cancer and may serve as potential therapeutic target.


Assuntos
Ciclina D1/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Neoplasias da Próstata/genética , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Masculino , Proteínas de Neoplasias/genética , Neoplasias da Próstata/patologia
10.
Phys Chem Chem Phys ; 21(34): 18559-18568, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31411206

RESUMO

The development of lithium-sulfur (Li-S) batteries is hindered by capacity loss due to lithium polysulfide (LIPS) dissolution into electrolyte solutions (known as the "shuttle effect"). MXenes with excellent electrical conductivity, high mechanical strength and multiple possible active two-dimensional surface terminations are attracting much attention as anchoring materials of Li-S batteries. Here, the S-functionalized V2C (V2CS2) is designed and demonstrated to have not only dynamic and thermal stability, but also metallic character. Compared with bare V2C and V2CO2, V2CS2 exhibits a moderate adsorption effect to suppress the "shuttle effect" and can preserve the structure of LIPSs without any decomposition. Moreover, the metallic properties of V2CS2 are maintained after LIPSs are adsorbed, which can promote the electrochemical activity during the charge and discharge process. The low energy barriers of Li2S decomposition and Li diffusion on the V2CS2 surface promise the phase transformation of LIPSs and assist the electrochemical process. Based on these remarkable results, we can conclude that V2CS2 is a promising anchoring material for lithium-sulfur batteries. Our work may also inspire the exploration of other MXenes and new surface functionalization methods to improve the performance of MXenes as host materials for high performance Li-S batteries.

11.
Mar Drugs ; 17(3)2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30832239

RESUMO

Glutathione S-transferases are one of the most important antioxidant enzymes to protect against oxidative damage induced by reactive oxygen species. In this study, a novel gst gene, designated as hsgst, was derived from Antarctic sea ice bacterium Halomonas sp. ANT108 and expressed in Escherichia coli (E. coli) BL21. The hsgst gene was 603 bp in length and encoded a protein of 200 amino acids. Compared with the mesophilic EcGST, homology modeling indicated HsGST had some structural characteristics of cold-adapted enzymes, such as higher frequency of glycine residues, lower frequency of proline and arginine residues, and reduced electrostatic interactions, which might be in relation to the high catalytic efficiency at low temperature. The recombinant HsGST (rHsGST) was purified to apparent homogeneity with Ni-affinity chromatography and its biochemical properties were investigated. The specific activity of the purified rHsGST was 254.20 nmol/min/mg. The optimum temperature and pH of enzyme were 25 °C and 7.5, respectively. Most importantly, rHsGST retained 41.67% of its maximal activity at 0 °C. 2.0 M NaCl and 0.2% H2O2 had no effect on the enzyme activity. Moreover, rHsGST exhibited its protective effects against oxidative stresses in E. coli cells. Due to its high catalytic efficiency and oxidative resistance at low temperature, rHsGST may be a potential candidate as antioxidant in low temperature health foods.


Assuntos
Antioxidantes/química , Organismos Aquáticos/fisiologia , Proteínas de Bactérias/química , Glutationa Transferase/química , Halomonas/fisiologia , Sequência de Aminoácidos , Regiões Antárticas , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Temperatura Baixa/efeitos adversos , Conservação de Alimentos/métodos , Glutationa Transferase/genética , Glutationa Transferase/isolamento & purificação , Glutationa Transferase/farmacologia , Concentração de Íons de Hidrogênio , Camada de Gelo/microbiologia , Simulação de Dinâmica Molecular , Estresse Oxidativo/fisiologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Especificidade por Substrato , Termotolerância/fisiologia
12.
Ecotoxicol Environ Saf ; 168: 356-362, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30391840

RESUMO

In this study, using a natural and green protein R-phycoerythrin (R-PE) extracted from marine Porphyra yezoensis as the stabilizer and reducer, silver nanoparticles (AgNPs) were synthesized. Based on this, a highly sensitive and selective method for the detection of Cu2+ ions was developed using R-PE-AgNPs as fluorescent probe. The interactions between R-PE-AgNPs and Cu2+ ions were systematically characterized by fluorescence spectroscopy, transmission electron microscopy (TEM), elemental mapping and Fourier transform infrared (FTIR). It was found that Cu2+ ions could cause aggregation of the R-PE-AgNPs, accompanied by the greatly increased particle size. Importantly, the method offered a wide linear detection range from 0 µM to 100.0 µM with a detection limit of 0.0190 µM. Moreover, the proposed method was successfully applied to analyze Cu2+ ions in tap water and lake water samples, acquiring satisfactory recovery between 91.6% and 102.2%. Such a green, fast and cost-effective fluorimetric method of the R-PE-AgNPs probe has great potential for tracing Cu2+ ions in diverse aqueous media.


Assuntos
Cobre/análise , Nanopartículas Metálicas/química , Ficoeritrina/metabolismo , Porphyra/metabolismo , Prata/química , Corantes Fluorescentes , Fluorometria , Limite de Detecção , Microscopia Eletrônica de Transmissão , Sensibilidade e Especificidade , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
13.
Molecules ; 24(12)2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31207974

RESUMO

A novel RNase R, psrnr, was cloned from the Antarctic bacterium Psychrobacter sp. ANT206 and expressed in Escherichia coli (E. coli). A bioinformatics analysis of the psrnr gene revealed that it contained an open reading frame of 2313 bp and encoded a protein (PsRNR) of 770 amino acids. Homology modeling indicated that PsRNR had reduced hydrogen bonds and salt bridges, which might be the main reason for the catalytic efficiency at low temperatures. A site directed mutation exhibited that His 667 in the active site was absolutely crucial for the enzyme catalysis. The recombinant PsRNR (rPsRNR) showed maximum activity at 30 °C and had thermal instability, suggesting that rPsRNR was a cold-adapted enzyme. Interestingly, rPsRNR displayed remarkable salt tolerance, remaining stable at 0.5-3.0 M NaCl. Furthermore, rPsRNR had a higher kcat value, contributing to its efficient catalytic activity at a low temperature. Overall, cold-adapted RNase R in this study was an excellent candidate for antimicrobial treatment.


Assuntos
Adaptação Biológica , Temperatura Baixa , Microbiologia Ambiental , Camada de Gelo/microbiologia , Psychrobacter/fisiologia , Ribonucleases/metabolismo , Tolerância ao Sal , Sequência de Aminoácidos , Regiões Antárticas , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Ativação Enzimática , Cinética , Modelos Biológicos , Conformação Molecular , Estrutura Molecular , Psychrobacter/isolamento & purificação , Ribonucleases/genética
14.
Mar Drugs ; 16(10)2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30275355

RESUMO

l-tert-leucine and its derivatives are useful as pharmaceutical active ingredients, in which leucine dehydrogenase (LeuDH) is the key enzyme in their enzymatic conversions. In the present study, a novel cold-adapted LeuDH, psleudh, was cloned from psychrotrophic bacteria Pseudoalteromonas sp. ANT178, which was isolated from Antarctic sea-ice. Bioinformatics analysis of the gene psleudh showed that the gene was 1209 bp in length and coded for a 42.6 kDa protein containing 402 amino acids. PsLeuDH had conserved Phe binding site and NAD⁺ binding site, and belonged to a member of the Glu/Leu/Phe/Val dehydrogenase family. Homology modeling analysis results suggested that PsLeuDH exhibited more glycine residues, reduced proline residues, and arginine residues, which might be responsible for its catalytic efficiency at low temperature. The recombinant PsLeuDH (rPsLeuDH) was purified a major band with the high specific activity of 275.13 U/mg using a Ni-NTA affinity chromatography. The optimum temperature and pH for rPsLeuDH activity were 30 °C and pH 9.0, respectively. Importantly, rPsLeuDH retained at least 40% of its maximum activity even at 0 °C. Moreover, the activity of rPsLeuDH was the highest in the presence of 2.0 M NaCl. Substrate specificity and kinetic studies of rPsLeuDH demonstrated that l-leucine was the most suitable substrate, and the catalytic activity at low temperatures was ensured by maintaining a high kcat value. The results of the current study would provide insight into Antarctic sea-ice bacterium LeuDH, and the unique properties of rPsLeuDH make it a promising candidate as a biocatalyst in medical and pharmaceutical industries.


Assuntos
Camada de Gelo/microbiologia , Leucina Desidrogenase/genética , Pseudoalteromonas/genética , Sequência de Aminoácidos , Aminoácidos/genética , Regiões Antárticas , Catálise , Temperatura Baixa , Concentração de Íons de Hidrogênio , Cinética , Alinhamento de Sequência , Especificidade por Substrato
15.
Nat Methods ; 11(5): 559-65, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24658142

RESUMO

Promoters and enhancers establish precise gene transcription patterns. The development of functional approaches for their identification in mammalian cells has been complicated by the size of these genomes. Here we report a high-throughput functional assay for directly identifying active promoter and enhancer elements called FIREWACh (Functional Identification of Regulatory Elements Within Accessible Chromatin), which we used to simultaneously assess over 80,000 DNA fragments derived from nucleosome-free regions within the chromatin of embryonic stem cells (ESCs) and identify 6,364 active regulatory elements. Many of these represent newly discovered ESC-specific enhancers, showing enriched binding-site motifs for ESC-specific transcription factors including SOX2, POU5F1 (OCT4) and KLF4. The application of FIREWACh to additional cultured cell types will facilitate functional annotation of the genome and expand our view of transcriptional network dynamics.


Assuntos
Elementos Facilitadores Genéticos , Regulação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Regiões Promotoras Genéticas , Animais , Sítios de Ligação , Cromatina/química , Biologia Computacional , Desoxirribonuclease I/metabolismo , Células-Tronco Embrionárias/citologia , Citometria de Fluxo , Biblioteca Gênica , Genes Reporter , Técnicas Genéticas , Genoma , Proteínas de Fluorescência Verde/metabolismo , Fator 4 Semelhante a Kruppel , Lentivirus/genética , Lentivirus/metabolismo , Luciferases/metabolismo , Camundongos , Plasmídeos/metabolismo , Transcrição Gênica , Transgenes
16.
PLoS One ; 19(7): e0305051, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38959232

RESUMO

The organizational forms of infrastructure in China are divided into two categories, the traditional Public Procurement Model (PUB) model and Public-Private Partnership(PPP) model. The main difference is the separation or binding of the construction and operation phases. A systematic understanding is needed of how Chinese local governments choose between these two models. In this paper, we take public capital congestion and local government objectives as the entry point to study the effects of both on PPP choice. Firstly, by constructing an endogenous economic growth model under the PPP model, and comparing it with the model under the PUB model, this paper initially explains how the rise in public capital congestion affects the choice of the PPP by growth-oriented local governments. Then the data from prefecture-level cities from 2009-2018 are utilized to conduct empirical tests. We find that urban economic growth pressures have a positive effect on the choice of PPP when the congestion of public capital increases. Furthermore, the implementation of PPP is indeed conducive to economic performance, and its core mechanism is to provide more infrastructure (like roads) rather than tax competition. The PPP model is more sustainable. We are the first to employ both modeling approach and the empirical research to address the implementation of Public-Private Partnership in China. And we have systematically analyzed the conditions and results of PPP selection by local governments. It formulates the Chinese PPP theory.


Assuntos
Parcerias Público-Privadas , China , Humanos , Desenvolvimento Econômico , Modelos Econômicos , Governo Local , Cidades
17.
J Phys Chem Lett ; 15(18): 4983-4991, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38691841

RESUMO

The exploration of two-dimensional (2D) materials with exceptional physical and chemical properties is essential for the advancement of solar water splitting technologies. However, the discovery of 2D materials is currently heavily reliant on fragmented studies with limited opportunities for fine-tuning the chemical composition and electronic features of compounds. Starting from the V2DB digital library as a resource of 2D materials, we set up and execute a funnel approach that incorporates multiple screening steps to uncover potential candidates for photocatalytic water splitting. The initial screening step is based upon machine learning (ML) predicted properties, and subsequent steps involve first-principles modeling of increasing complexity, going from density functional theory (DFT) to hybrid-DFT to GW calculations. Ensuring that at each stage more complex calculations are only applied to the most promising candidates, our study introduces an effective screening methodology that may serve as a model for accelerating 2D materials discovery within a large chemical space. Our screening process yields a selection of 11 promising 2D photocatalysts.

18.
Bioresour Technol ; 399: 130539, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38458264

RESUMO

Carbonic anhydrase (CA) is currently under investigation because of its potential to capture CO2. A novel N-domain of ice nucleoproteins (INPN)-mediated surface display technique was developed to produce CA with low-temperature capture CO2 based on the mining and characterization of Colwellia sp. CA (CsCA) with cold-adapted enzyme structural features and catalytic properties. CsCA and INPN were effectively integrated into the outer membrane of the cell as fusion proteins. Throughout the display process, the integrity of the membrane of engineered bacteria BL21/INPN-CsCA was maintained. Notably, the study affirmed positive applicability, wherein 94 % activity persisted after 5 d at 15 °C, and 73 % of the activity was regained after 5 cycles of CO2 capture. BL21/INPN-CsCA displayed a high CO2 capture capacity of 52 mg of CaCO3/mg of whole-cell biocatalysts during CO2 mineralization at 25 °C. Therefore, the CsCA functional cell surface display technology could contribute significantly to environmentally friendly CO2 capture.


Assuntos
Dióxido de Carbono , Anidrases Carbônicas , Dióxido de Carbono/metabolismo , Anidrases Carbônicas/metabolismo , Técnicas de Visualização da Superfície Celular , Bactérias/metabolismo , Catálise
19.
Waste Manag ; 170: 270-277, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37729844

RESUMO

As a class of organic micropollutants of global concern, pharmaceuticals have prevalent distributions in the aqueous environment (e.g., groundwater and surface water) and solid matrices (e.g., soil, sediments, and dried sludge). Their contamination levels have been further aggravated by the annually increased production of expired drugs as emerging harmful wastes worldwide. Sulfate radicals (SO4•-)-based oxidation has attracted increasing attention for abating pharmaceuticals in the environment, whereas the transformation mechanisms of solid-phase pharmaceuticals remain unknown thus far. This investigation presented for the first time that SO4•-, individually produced by mechanical force-activated and heat-activated persulfate treatments, could effectively oxidize three model pharmaceuticals (i.e., methotrexate, sitagliptin, and salbutamol) in both solid and liquid phases. The high-resolution mass spectrometric analysis suggested their distinct transformation products formed by different phases of SO4•- oxidation. Accordingly, the SO4•--mediated mechanistic differences between the solid-phase and liquid-phase pharmaceuticals were proposed. It is noteworthy that the products from both systems were predicted with the remaining persistence, bioaccumulation, and multi-endpoint toxicity. Therefore, some post-treatment strategies need to be considered during practical applications of SO4•--based technologies in remediating different phases of micropollutants. This work has environmental implications for understanding the comparative transformation mechanisms of pharmaceuticals by SO4•- oxidation in remediating the contaminated solid and aqueous matrices.

20.
Bioresour Technol ; 382: 129164, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37207695

RESUMO

To eliminate efficiency restriction of polyethylene microplastics low-temperature biodegradation, a novel InaKN-mediated Escherichia coli surface display platform for cold-active degrading laccase PsLAC production was developed. Display efficiency of 88.0% for engineering bacteria BL21/pET-InaKN-PsLAC was verified via subcellular extraction and protease accessibility, exhibiting an activity load of 29.6 U/mg. Cell growth and membrane integrity revealed BL21/pET-InaKN-PsLAC maintained stable growth and intact membrane structure during the display process. The favorable applicability was confirmed, with 50.0% activity remaining in 4 days at 15 °C, and 39.0% activity recovery retention after 15 batches of activity substrate oxidation reactions. Moreover, BL21/pET-InaKN-PsLAC possessed high polyethylene low-temperature depolymerizing capacity. Bioremediation experiments proved that the degradation rate was 48.0% within 48 h at 15 °C, and reached 66.0% after 144 h. Collectively, cold-active PsLAC functional surface display technology and its significant contributions to polyethylene microplastics low-temperature degradation constitute an effective improvement strategy for biomanufacturing and microplastics cold remediation.


Assuntos
Lacase , Polietileno , Lacase/metabolismo , Microplásticos , Plásticos , Temperatura , Biodegradação Ambiental
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