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1.
J Med Internet Res ; 23(5): e25554, 2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-33944787

RESUMO

BACKGROUND: As a type of donation-based crowdfunding, medical crowdfunding has gradually become an important way for patients who have difficulty paying medical bills to seek help from the public. However, many people still have limited confidence in donating money to medical crowdfunding projects. OBJECTIVE: Given that the features of a medical crowdfunding website may be important to gain users' trust, this study draws upon two-factor and trust theories to explore how different design features of medical crowdfunding websites affect potential donors' cognition-based trust and affect-based trust, and how these types of trust affect the intention to donate. METHODS: A 2 (informativeness: high vs low) × 2 (visual cues: cool color vs warm color) × 2 (social cues: with vs without) between-subject laboratory experiment was performed to validate our research model. A total of 320 undergraduate students recruited from a university in China participated in the controlled laboratory experiment. RESULTS: Cognition-based trust (ß=.528, P<.001) and affect-based trust (ß=.344, P<.001) exerted significant effects on the intention to donate of potential donors of medical crowdfunding. Informativeness as a hygiene factor positively influenced potential donors' cognition-based trust (F1,311=49.764, P<.001) and affect-based trust (F1,311=16.093, P<.001), whereas social cues as a motivating factor significantly influenced potential donors' cognition-based trust (F1,311=38.160, P<.001) and affect-based trust (F1,311=23.265, P<.001). However, the color of the webpages affected the two dimensions of trust differently. Specifically, medical crowdfunding webpages with warm colors were more likely to induce affect-based trust than those with cool colors (F1,311=17.120, P<.001), whereas no significant difference was found between the effects of cool and warm colors on cognition-based trust (F1,311=1.707, P=.19). CONCLUSIONS: This study deepens our understanding of the relationships among the design features of medical crowdfunding websites, trust, and intention to donate, and provides guidelines for managers of medical crowdfunding platforms to enhance potential donors' trust-building by improving the website design features.

2.
Food Chem ; 358: 129888, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33933969

RESUMO

Present study aimed to prepare and identify antioxidative peptides from selenium-containing soybeans, and to investigate their bioavailability and protective effects against oxidative stress-related diseases. Selenium-containing soybean antioxidative peptides (Mw < 1 kDa, SePPs) hydrolyzed by Neutrase and Alcalase reached the highest cellular antioxidant activity (EC50 value 320.5 ± 39.71 µg/L). SePPs could be efficiently absorbed through Caco-2 monolayer, and then significantly reverse the tumor necrosis factor-α (TNF-α)-induced inflammatory cytokine, phosphorylated c-Jun N-terminal kinases (p-JNK) and nuclear factor-kappa B (NF-κB) levels in EA. hy926 cells (p < 0.05). d-galactose-induced aging mice model showed that liver superoxidase dismutase (SOD) and glutathione peroxidase-1 (GPx-1) were enhanced, while aspartate aminotransferase (AST), alanine aminotransferase (ALT) and NF-κB were decreased by SePPs significantly (p < 0.05). SePPs could inhibit brain oxidative stress via regulating MAPK/NF-κB pathway. Comparing with Na2SeO3, selenomethionine (SeMet) and selenium-free peptides, SePPs was found to present synergistic effects of selenium and peptides in antioxidant activity.

3.
J Int Med Res ; 49(5): 3000605211010051, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33951980

RESUMO

BACKGROUND: We examined the association of the Geriatric Nutritional Risk Index (GNRI) with the incidence of hypertension. METHODS: We used data of the China Health and Nutrition Survey in this study. Participants aged ≥60 years were eligible. The GNRI was defined as follows: GNRI = [1.489 × albumin (ALB; g/L)] + [41.7 × (actual weight/ideal weight)]. Participants with systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or use of antihypertensive medication were defined as having hypertension. RESULTS: This study included 4853 participants, comprising 3612 control participants and 1241 participants with hypertension. The GNRI, ALB, and body mass index (BMI) were significantly associated with higher incidence of hypertension (HR: 1.030, 1.026, and 1.088; 95% CI: 1.020-1.041, 1.008-1.044, and 1.069-1.107, respectively). The GNRI, ALB, and BMI were associated with an earlier age of hypertension onset (ß = -0.403, -0.613, and -0.321; 95% CI: -0.493 to -0.314, -0.767 to -0.459, and -0.484 to -0.159, respectively). CONCLUSIONS: A higher GNRI was associated with increased incidence of hypertension. An elevated GNRI was associated with earlier age of hypertension onset.

4.
Epigenomics ; 2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-33955785

RESUMO

Aim: To explore tumor immune microenvironment and identify immune prognostic-related circRNAs in cervical cancer. Materials & methods: RNA-seq in combination with bioinformatics were performed to establish a prognostic risk model and a circRNAs-miRNAs-CXCL8 network. Results: High-risk group correlated with poor survival outcome, and had lower PD-1 immunogenicity. Additionally, CXCL8 could distinguish normal tissue, low- and high-risk tumor tissues, the expression of which showed an increasing trend among the three groups. RNA-seq and bioinformatics indicated that circRNAs like hsa_circ_0025721 might upregulate CXCL8 through sponging miRNAs including hsa-miR-4428. Conclusion: We constructed an immune risk model related with CD8 T cells to predict the cervical cancer patients' prognosis and explored the abnormal expression mechanism of CXCL8 through the ceRNA mechanism.

5.
Cell ; 2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33882274

RESUMO

The bacterial flagellar motor is a supramolecular protein machine that drives rotation of the flagellum for motility, which is essential for bacterial survival in different environments and a key determinant of pathogenicity. The detailed structure of the flagellar motor remains unknown. Here we present an atomic-resolution cryoelectron microscopy (cryo-EM) structure of the bacterial flagellar motor complexed with the hook, consisting of 175 subunits with a molecular mass of approximately 6.3 MDa. The structure reveals that 10 peptides protruding from the MS ring with the FlgB and FliE subunits mediate torque transmission from the MS ring to the rod and overcome the symmetry mismatch between the rotational and helical structures in the motor. The LP ring contacts the distal rod and applies electrostatic forces to support its rotation and torque transmission to the hook. This work provides detailed molecular insights into the structure, assembly, and torque transmission mechanisms of the flagellar motor.

6.
J Vis Exp ; (170)2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33900282

RESUMO

Neovascularization is usually initialized from an existing normal vasculature and the biomechanical microenvironment of endothelial cells (ECs) in the initial stage varies dramatically from the following process of neovascularization. Although there are plenty of models to simulate different stages of neovascularization, an in vitro 3D model that capitulates the initial process of neovascularization under the corresponding stimulations of normal vasculature microenvironments is still lacking. Here, we reconstructed an in vitro 3D model that mimics the initial event of neovascularization (MIEN). The MIEN model contains a microfluidic sprouting chip and an automatic control, highly efficient circulation system. A functional, perfusable microchannel coated with endothelium was formed and the process of sprouting was simulated in the microfluidic sprouting chip. The initially physiological microenvironment of neovascularization was recapitulated with the microfluidic control system, by which ECs would be exposed to high luminal shear stress, physiological transendothelial flow, and various vascular endothelial growth factor (VEGF) distributions simultaneously. The MIEN model can be readily applied to the study of neovascularization mechanism and holds a potential promise as a low-cost platform for drug screening and toxicology applications.

7.
Mikrochim Acta ; 188(5): 153, 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33821319

RESUMO

A novel oxygen-doped g-C3N4 nanoplate (OCNP) structure that can serve as an efficient sulfadimethoxine (SDM) sensing platform has been developed. Taking advantage of its inherent oxygen-containing functional groups and 2D layered structure with π-conjugated system, OCNP exhibits effective radiative recombination of surface-confined electron-hole pairs and efficient π-π interaction with SDM. This causes rapid fluorescence response and thus ensures the fast and continuous monitoring of SDM. Based on the fluorescence experiments and band structure calculation, the mechanism of the SDM-induced quenching phenomenon was mainly elucidated as the photoinduced electron transfer process under a dynamic quenching mode. Under optimized conditions, the as-proposed nanosensor, which emitted strong fluorescence at 375 nm with an excitation wavelength at 255 nm, presents an excellent analytical performance toward SDM with a wide linear range from 3 to 60 µmol L-1 and a detection limit of 0.85 µmol L-1 (S/N = 3). In addition, this strategy exhibits satisfactory recovery varied from 94 to 103% with relative standard derivations (RSD) in the range 0.9 to 6.8% in real water samples. It also shows marked tolerability to a series of high concentrations of metals and inorganic salts. This strategy not only broadens the application of oxygen-doped g-C3N4 nanomaterial in antibiotic sensing field but also presents a promising potential for on-line contaminant tracing in complex environments.

8.
Medicine (Baltimore) ; 100(14): e25375, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33832123

RESUMO

RATIONALE: Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare congenital malformation in neonates that results in severe respiratory distress and pulmonary hypertension. ACD/MPV is caused by mutations in the FOXF1 gene. Herein, a new case of a girl with ACD/MPV carrying a novel pathogenic variant of FOXF1 was reported. PATIENT CONCERNS: A 3-month-old Chinese girl was admitted to the hospital presenting a complaint of cyanosis for 10 days and respiratory distress for 2 days. The history of foreign body inhalation was denied. DIAGNOSES: Blood routine, liver and kidney function, electrolytes, type B natriuretic peptide, electrocardiogram, cardiac computed tomography (CT), and echocardiography were done after admission. Dysplasia of the alveolar and the left upper pulmonary vein was displayed through cardiac CT. Echocardiography showed atrial septal defect, tricuspid valve malformation, and pulmonary hypertension. Sequence analysis of FOXF1 from genomic deoxyribonucleic acid (DNA) revealed that the patient was heterozygous for a novel missense variant (c.418 C>T, p.Pro140Gly). Furthermore, genetic analysis of both parents confirmed the de novo occurrence of the variant. Conservation analysis showed that the locus was highly conserved across species. Then, ACD/MPV was a clinical diagnosis. INTERVENTIONS: After admission, nasal catheter oxygen inhalation, cefazoxime sodium, furosemide diuretic, milrinone lactate, and Bosentan were given to the patient. OUTCOMES: After 6 days of hospitalization, the patient's condition did not improved, the parents gave up treatment and discharged. The patient died half a month after discharge. LESSONS: ACD/MPV is a rare congenital malformation with a poor prognosis. A new de novo mutation of FOXF1 was found in our case. Non-invasive methods such as DNA sequencing and FOXF1 analysis are helpful in the clinical diagnosis of ACD/MPV especially in early infants with respiratory distress and pulmonary hypertension.


Assuntos
Fatores de Transcrição Forkhead/genética , Síndrome da Persistência do Padrão de Circulação Fetal/diagnóstico , Síndrome da Persistência do Padrão de Circulação Fetal/genética , Alvéolos Pulmonares/anormalidades , Veias Pulmonares/anormalidades , Ecocardiografia/métodos , Evolução Fatal , Feminino , Comunicação Interatrial/diagnóstico por imagem , Comunicação Interatrial/genética , Heterozigoto , Humanos , Hipertensão Pulmonar/diagnóstico por imagem , Hipertensão Pulmonar/genética , Lactente , Mutação de Sentido Incorreto , Oxigenoterapia/métodos , Síndrome da Persistência do Padrão de Circulação Fetal/tratamento farmacológico , Análise de Sequência/métodos , Falha de Tratamento , Valva Tricúspide/anormalidades , Valva Tricúspide/diagnóstico por imagem
9.
Ultrasound Med Biol ; 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33858722

RESUMO

The conventional manual approach to measurement of aortic pulse wave velocity (PWV) by Doppler ultrasonography is time consuming and operator dependent. Here we report a new semi-automated methodology for more efficient and objective measurement of aortic PWV and results of tests of its clinical feasibility and reproducibility. Carotid-femoral pulse wave velocity (cfPWV) was measured in 50 patients with suspected coronary artery disease (aged 59.2 ± 10.0 y, 36 males) by three independent observers, including two experienced sonographers and one cardiologist without ultrasonographic experience. The cfPWV measured by the semi-automatic method (cfPWVA) was compared with reference values obtained by averaging measurements by two experienced sonographers using the conventional standard manual method (cfPWVM). Measurements of cfPWVA were feasible in all 50 patients and exhibited excellent agreement with averaged cfPWVM from the two experienced sonographers, with an intraclass correlation coefficient (ICC) of 0.915 (95% confidence interval: 0.876-0.942). The inexperienced observer-measured cfPWVA did not differ from the cfPWVM measured by the two experienced sonographers (8.04 ± 1.29 vs. 8.14 ± 1.32 m/s, p > 0.05), with a high consistency by ICC of 0.877 (0.793-0.928). Bland-Altman plots further illustrated the good agreement between the two methods and good intra- and inter-observer reproducibility. Time consumption for cfPWV measurement using the new method was significantly less than that for the manual method (122 ± 35 s vs. 455 ± 105 s, p < 0.0001), saving about 73% of the time. This new semi-automatic methodology for aortic PWV measurement not only has an accuracy similar to that of the conventional standard manual method but is also highly feasible and time saving. It may provide a reliable, simple and reproducible approach to arterial stiffness evaluation in clinical settings.

10.
J Agric Food Chem ; 69(17): 4981-4991, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33900073

RESUMO

Previous studies have suggested that multiwalled carbon nanotubes (MWCNTs) promote plant growth; however, the mechanism is yet to be fully understood. In this study, the effects of MWCNTs (20, 100, and 500 mg/L) on the carbon (C) and nitrogen (N) metabolism in maize were studied to explore the molecular mechanism of the action of MWCNTs on plants. The results showed that 100 mg/L MWCNTs increased the shoot fresh and dry weight, root fresh weight, and seedling length while other doses showed no significant effects. Further studies showed that 100 mg/L MWCNTs increased the chlorophyll content, transpiration rate, stomatal conductance, and intercellular CO2 concentration, by 50.6%, 60.8%, 47.2%, and 32.1%, respectively. Activities of key enzymes including sucrose synthase (SS), sucrose phosphate synthase (SPS) and phosphoenolpyruvate carboxylase (PEPC) that are involved in the carbon metabolism, and nitrate reductase (NR), glutamine synthetase (GS), and glutamate synthetase (GOGAT) that are involved in N metabolism, were all upregulated by 100 mg/L MWCNTs, which contributed to the increase of the accumulation of carbohydrates (sugar and starch), soluble protein, and N in plants. These findings suggest that MWCNTs can improve plant growth by regulating the key enzymes involved in C and N metabolism thereby enhancing the carbohydrate production and the use of N and improving plant growth. This study provides significant insights into the molecular mechanism of the positive effects of MWCNTs on plants and provide a basis for the agricultural application of MWCNTs.

11.
ACS Appl Mater Interfaces ; 13(17): 19710-19725, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33890760

RESUMO

Treatment resistance of the tumors to photodynamic therapy (PDT) owing to O2 deficiency largely compromised the therapeutic efficacy, which could be addressed via modulating oxygen levels by using O2 self-enriched nanosystems. Here, we report on augmenting the O2-evolving strategy based on a biomimetic, catalytic nanovehicle (named as N/P@MCC), constructed by the catalase-immobilized hollow mesoporous nanospheres by enveloping a cancer cell membrane (CCM), which acts as an efficient nanocontainer to accommodate nitrogen-doped graphene quantum dots (N-GQDs) and protoporphyrin IX (PpIX). Inheriting the virtues of biomimetic CCM cloaking, the CCM-derived shell conferred N/P@MCC nanovehicles with highly specific self-recognition and homotypic targeting toward cancerous cells, ensuring tumor-specific accumulation and superior circulation durations. N-GQDs, for the first time, have been evidenced as a new dual-functional nanoagents with PTT and PDT capacities, enabling the generation of 1O2 for PDT and inducing local low-temperature hyperthermia for thermally ablating cancer cells and infrared thermal imaging (IRT). Leveraging the intrinsic catalytic features of catalase, such N/P@MCC nanovehicles effectively scavenged the excessive H2O2 to sustainably evolve oxygen for a synchronous O2 self-supply and hypoxia alleviation, with an additional benefit because the resulting O2 bubbles could function as an echo amplifier, leading to the sufficient echogenic reflectivity for ultrasound imaging. Concurrently, the elevated O2 reacted with N-GQDs and PpIX to elicit a maximally increased 1O2 output for augmented PDT. Significantly, the ultrasound imaging coupled with fluorescence imaging, IRT, performs a tumor-modulated trimodal bioimaging effect. Overall, this offers a paradigm to rationally explore O2 self-supply strategies focused on versatile nanotheranostics for hypoxic tumor elimination.

12.
New Phytol ; 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33792940

RESUMO

Investigation into plant-fungal pathogen interactions is one of the most interesting fields in plant sciences. However, the roles of plant volatile organic compounds in the arms race are still largely unknown. Based on precise quantification of plant volatiles, we discovered that the plant volatile organic compound (E)-2-hexenal, at concentrations that were similar to or lower than those in tissues of strawberry and tomato fruits, upregulates sulfate assimilation in spores and hyphae of the phytopathogenic fungus Botrytis cinerea. This upregulation is independent of the types of sulfur sources in the plant and can be achieved in the presence of inorganic sulfate and organic sulfur sources. Using the fungal deletion mutants, we further found that sulfate assimilation is involved in the infection of tomato and strawberry fruits by B. cinerea, and that the severity of the disease is proportional to the sulfate content in the fruits. Both before and during the infection, (E)-2-hexenal induced utilisation of plant sulfate by B. cinerea facilitates its pathogenesis through enhancing its tolerance to oxidative stress. This work provides novel insights into the role of plant volatiles in plant-fungal pathogen interaction and highlights the importance of sulfur levels in the host in the prevention of grey mould disease.

14.
Nucleic Acids Res ; 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33877329

RESUMO

DNA cytosine methylation in mammals modulates gene expression and chromatin accessibility. It also impacts mutation rates, via spontaneous oxidative deamination of 5-methylcytosine (5mC) to thymine. In most cases the resulting T:G mismatches are repaired, following T excision by one of the thymine DNA glycosylases, TDG or MBD4. We found that C-to-T mutations are enriched in the binding sites of CCAAT/enhancer binding proteins (CEBP). Within a CEBP site, the presence of a T:G mismatch increased CEBPß binding affinity by a factor of >60 relative to the normal C:G base pair. This enhanced binding to a mismatch inhibits its repair by both TDG and MBD4 in vitro. Furthermore, repair of the deamination product of unmethylated cytosine, which yields a U:G DNA mismatch that is normally repaired via uracil DNA glycosylase, is also inhibited by CEBPß binding. Passage of a replication fork over either a T:G or U:G mismatch, before repair can occur, results in a C-to-T mutation in one of the daughter duplexes. Our study thus provides a plausible mechanism for accumulation of C-to-T human somatic mutations.

15.
Nat Struct Mol Biol ; 28(4): 347-355, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33782615

RESUMO

Lipoproteins in the outer membrane of Gram-negative bacteria are involved in various vital physiological activities, including multidrug resistance. Synthesized in the cytoplasm and matured in the inner membrane, lipoproteins must be transported to the outer membrane through the Lol pathway mediated by the ATP-binding cassette transporter LolCDE in the inner membrane via an unknown mechanism. Here, we report cryo-EM structures of Escherichia coli LolCDE in apo, lipoprotein-bound, LolA-bound, ADP-bound and AMP-PNP-bound states at a resolution of 3.2-3.8 Å, covering the complete lipoprotein transport cycle. Mutagenesis and in vivo viability assays verify features of the structures and reveal functional residues and structural characteristics of LolCDE. The results provide insights into the mechanisms of sorting and transport of outer-membrane lipoproteins and may guide the development of novel therapies against multidrug-resistant Gram-negative bacteria.

16.
Eur J Med Chem ; 217: 113363, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33744687

RESUMO

The combination of photodynamic therapy (PDT) and chemotherapy is a prospective strategy to improve antitumor efficacy. Herein, a series of novel cytotoxic chlorin-based derivatives as dual photosensitizers (PSs) and histone deacetylase inhibitors (HDACIs) were synthesized and investigated for biological activity. Among them, compound 15e showed definite HDAC2 and 10 inhibitory activities by up-regulating expression of acetyl-H4 and highest phototoxicity and dark-toxicity, which was more phototoxic than Talaporfin as a PS while with stronger dark-toxicity compared to vorinostat (SAHA) as a HDACI. The biological assays demonstrated that 15e was liable to enter A549 cells and localized in mitochondria, lysosomes, golgi and endoplasmic reticulum (ER) etc. multiple organelles, resulting in higher cell apoptosis rate and ROS production compared to Talaporfin. Moreover, it could induce tumor cell autophagy as a dual PS and HDACI. All results suggested that compound 15e could be applied as a potential dual cytotoxic drug for PDT and chemotherapy.

17.
Theranostics ; 11(10): 4929-4944, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33754036

RESUMO

Rationale: Recently, long non-coding RNAs (lncRNAs), known to be involved in human cancer progression, have been shown to encode peptides with biological functions, but the role of lncRNA-encoded peptides in cellular senescence is largely unexplored. We previously reported the tumor-suppressive role of PINT87aa, a peptide encoded by the long intergenic non-protein coding RNA, p53 induced transcript (LINC-PINT). Here, we investigated PINT87aa's role in hepatocellular carcinoma (HCC) cellular senescence. Methods: We examined PINT87aa and truncated PINT87aa functions in vitro by monitoring cell proliferation and performed flow cytometry, senescence-associated ß-galactosidase staining, JC-1 staining indicative of mitochondrial membrane potential, the ratio of the overlapping area of light chain 3 beta (LC3B) and mitochondrial probes and the ratio of lysosomal associated membrane protein 1 (LAMP1) overlapping with cytochrome c oxidase subunit 4I1 (COXIV) denoting mitophagy. PINT87aa and truncated PINT87aa functions in vivo were verified by subcutaneously transplanted tumors in nude mice. The possible binding between PINT87aa and forkhead box M1 (FOXM1) was predicted through structural analysis and verified by co-immunoprecipitation and immunofluorescence co-localization. Rescue experiments were performed in vivo and in vitro following FOXM1 overexpression. Further, chromatin immunoprecipitation, polymerase chain reaction, and dual-luciferase reporter gene assay were conducted to validate FOXM1 binding to the prohibitin 2 (PHB2) promoter. Results: PINT87aa was significantly increased in the hydrogen peroxide-induced HCC cell senescence model. Overexpression of PINT87aa induced growth inhibition, cellular senescence, and decreased mitophagy in vitro and in vivo. In contrast, FOXM1 gain-of-function could partially reduce the proportion of senescent HCC cells and enhance mitophagy. PINT87aa overexpression did not affect the expression of FOXM1 itself but reduced that of its target genes involved in cell cycle and proliferation, especially PHB2, which was involved in mitophagy and transcribed by FOXM1. Structural analysis indicated that PINT87aa could bind to the DNA-binding domain of FOXM1, which was confirmed by co-immunoprecipitation and immunofluorescence co-localization. Furthermore, we demonstrated that the 2 to 39 amino acid truncated form of the peptide exerted effects similarly to the full form. Conclusion: Our study established the role of PINT87aa as a novel biomarker and a key regulator of cellular senescence in HCC and identified PINT87aa as a potential therapeutic target for HCC.

18.
J Agric Food Chem ; 69(13): 3887-3894, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33764060

RESUMO

In the enzymatic cascade catalysis, it is a big challenge to construct a stable and reusable catalyst with targeted enzymes. The artificial multienzyme reactor has attracted great attention due to its potential for facilitating the performance of enzyme catalysis. In this study, we set up a reliable system that could assemble polyphosphate kinase (PPK) with bifunctional glutathione synthetase (GshF) via SpyCatcher/SpyTag to form multienzyme systems (MESs). Furthermore, MESs could assemble into nanoaggregates by altering the ionic strength, and the larger nanoaggregates could be applied in robust and reusable synthesis of glutathione (GSH). To enhance MES levels in vivo, gene duplication and different coexpression modes were performed. Finally, the optimized production of GSH and oxidized glutathione (GSSG) reached 102.6 and 6.7 mM within 2 h. Compared with the first round, the total yield only decreased by 9.4% after five continuous rounds of biocatalysis.

19.
Molecules ; 26(5)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33669147

RESUMO

An aniline-functionalized naphthalene dialdehyde Schiff base fluorescent probe L with aggregation-induced enhanced emission (AIEE) characteristics was synthesized via a simple one-step condensation reaction and exhibited excellent sensitivity and selectivity towards copper(II) ions in aqueous media with a fluorescence " turn-off " phenomenon. The detection limit of the probe is 1.64 × 10-8 mol·L-1. Furthermore, according to the results of the UV-vis/fluorescence titrations, Job's plot method and 1H-NMR titrations, a 1:2 stoichiometry was identified. The binding constant between L and Cu2+ was calculated to be Ka = 1.222 × 103. In addition, the AIEE fluorescent probe L could be applied to detection in real water samples with satisfactory recoveries in the range 99.10-102.90% in lake water and 98.49-102.37% in tap water.


Assuntos
Cobre/análise , Corantes Fluorescentes/química , Naftalenos/química , Poluentes Químicos da Água/análise , Cristalografia por Raios X , Corantes Fluorescentes/síntese química , Íons/análise , Modelos Moleculares , Estrutura Molecular , Naftalenos/síntese química , Bases de Schiff/síntese química , Bases de Schiff/química
20.
ACS Appl Mater Interfaces ; 13(13): 15881-15889, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33779139

RESUMO

Dye sensitization achieving photoelectrochemical (PEC) signal amplification for ultrasensitive bioanalysis has undergone a major breakthrough. In this proposal, an innovative PEC sensing platform is developed by combining Z-scheme WO3@SnS2 photoactive materials and a G-wire superstructure as well as a dye sensitization enhancement strategy. The newly synthesized WO3@SnS2 heterojunction with outstanding PEC performance is employed as a photoelectrode matrix. Due to the formation of the Z-scheme heterojunction between WO3 and SnS2, the migration dynamics of the photogenerated carrier is evidently augmented. To improve sensitivity, the target excision-driven dual-cycle signal amplification strategy is introduced to output exponential c-myc fragments. Crystal violet is then conjugated into the G-quadruplex to amplify the PEC signal, where crystal violet generates excited electrons by capturing visible light and rapidly injects electrons into the conduction band of SnS2, suppressing the recombination of the photo-induced carrier. Moreover, the G-wire superstructure acts as a universal amplification pathway, ensuring adequate crystal violet loads. Specifically, the biosensor for uracil-DNA glycosylase quantification displays a wide detection range (0.0005-1.0 U/mL) and a lower detection limit (0.00025 U/mL). Furthermore, the Z-scheme electron migration mechanism and the crystal violet sensitization effect are discussed in detail. The construction of the PEC sensor provides a new consideration for signal amplification and material design.

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