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1.
Appl Microbiol Biotechnol ; 108(1): 85, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38189948

RESUMO

Equine infectious anemia (EIA) is a contagious disease of horses caused by the equine infectious anemia virus (EIAV). The clinical signs at the acute phase include intermittent high fever, thrombocytopenia, hemorrhage, edema, and anemia. The clinical signs at chronic and relapsing subclinical levels include emaciation and progressive weakness. Surviving horses become lifelong carriers because of the integration of the viral genome into that of the host, and these horses can produce and transmit the virus to other animals. This increases the difficulty of imposing practical control measures to prevent epidemics of this disease. Serological tests measuring the antibodies in equine sera are considered to be a reliable tool for the long-term monitoring of EIA. However, the standard serological tests for EIV either have low sensitivity (e.g., agar gel immunodiffusion test, AGID) or are time consuming to perform (e.g., ELISA and western blotting). The development of a rapid and simple method for detecting the disease is therefore critical to control the spread of EIA. In this study, we designed and developed a colloidal gold immunochromatographic (GICG) test strip to detect antibodies against EIAV based on the double-antigen sandwich. Both the p26 and gp45 proteins were used as the capture antigens, which may help to improve the positive detection rate of the strip. We found that the sensitivity of the test strip was 8 to 16 times higher than those of two commercially available ELISA tests and 128 to 256 times higher than AGID, but 8 to 16 times lower than that of western blotting. The strip has good specificity and stability. When serum samples from experimental horses immunized with the attenuated EIAV vaccine (n = 31) were tested, the results of the test strip showed 100% coincidence with those from NECVB-cELISA and 70.97% with AGID. When testing clinical serum samples (n = 1014), the test strip surprisingly provided greater sensitivity and a higher number of "true positive" results than other techniques. Therefore, we believe that the GICG test strip has demonstrated great potential in the field trials as a simple and effective tool for the detection of antibodies against EIAV. KEY POINTS: • A colloidal gold immunochromatographic (GICG) fast test strip was developed with good specificity, sensitivity, stability, and repeatability • The test strip can be used in point-of-care testing for the primary screening of EIAV antibodies • Both the p26 and gp45 proteins were used as the capture antigens, giving a high positive detection rate in the testing of experimentally infected animal and field samples.


Assuntos
Vírus da Anemia Infecciosa Equina , Animais , Cavalos , Anticorpos Antivirais , Ensaio de Imunoadsorção Enzimática , Western Blotting , Coloide de Ouro
2.
Biochem Biophys Res Commun ; 660: 43-49, 2023 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-37062240

RESUMO

The COVID-19 pandemic, caused by SARS-CoV-2, has led to over 750 million infections and 6.8 million deaths worldwide since late 2019. Due to the continuous evolution of SARS-CoV-2, many significant variants have emerged, creating ongoing challenges to the prevention and treatment of the pandemic. Therefore, the study of antibody responses against SARS-CoV-2 is essential for the development of vaccines and therapeutics. Here we perform single particle cryo-electron microscopy (cryo-EM) structure determination of a rabbit monoclonal antibody (RmAb) 9H1 in complex with the SARS-CoV-2 wild-type (WT) spike trimer. Our structural analysis shows that 9H1 interacts with the receptor-binding motif (RBM) region of the receptor-binding domain (RBD) on the spike protein and by directly competing with angiotensin-converting enzyme 2 (ACE2), it blocks the binding of the virus to the receptor and achieves neutralization. Our findings suggest that utilizing rabbit-derived mAbs provides valuable insights into the molecular interactions between neutralizing antibodies and spike proteins and may also facilitate the development of therapeutic antibodies and expand the antibody library.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/metabolismo , Anticorpos Monoclonais , Pandemias , Microscopia Crioeletrônica , Anticorpos Antivirais , Receptores Virais/metabolismo , Anticorpos Neutralizantes , Ligação Proteica , Glicoproteína da Espícula de Coronavírus/química
3.
J Clin Microbiol ; 61(11): e0027323, 2023 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-37874302

RESUMO

The high abortion rate associated with Salmonella Abortusequi (S. Abortusequi) infection in equids has re-emerged over the past 10 years and has caused serious economic losses to China. Our previous studies showed that the flagellin FljB gene could distinguish S. Abortusequi from most Salmonella serotypes. In this study, the flagellin antigen was used to develop a competitive enzyme-linked immunosorbent assay (cELISA) that could be used to detect both horse and donkey serum samples using a monoclonal antibody (MAb) that was found to bind to FljB. A cELISA was established using the purified MAb coating of the plate and incubation of the mixture of horseradish peroxidase (HRP)-conjugated FljB antigen with the undiluted serum sample. The performance of the cELISA and the tube agglutination test (TAT) assay was compared with respect to sensitivity and specificity, by testing a panel containing 660 S. Abortusequi-positive and 515 S. Abortusequi-negative serum samples, all of which had been characterized by Western blotting. Receiver operator characteristic (ROC) analyses were performed to determine the cutoff value and estimate the detection specificity (Sp) and sensitivity (Se). ROC analysis showed that the area under the ROC curve (AUC) values of cELISA [AUC = 0.9941; 95% confidence interval (CI), 0.9898-0.9984] were higher than those of TAT (AUC = 0.7705; 95% Cl, 0.7437-0.7972). A cutoff value of 39.5% was selected with Sp and Se values of 100 (95% Cl, 99.26-100.00) and 97.58 (95% Cl, 96.10-98.50), respectively. The cELISA has excellent futures compared with TAT, such as shortened detection time, no need for pre-treatment of sera, and easy interpretation of the results, and is more suitable for disease surveillance.


Assuntos
Anticorpos Monoclonais , Flagelina , Feminino , Gravidez , Animais , Cavalos , Ensaio de Imunoadsorção Enzimática/métodos , Sensibilidade e Especificidade , Salmonella , Anticorpos Antivirais
4.
J Clin Microbiol ; 61(3): e0137522, 2023 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-36856425

RESUMO

Salmonella enterica subsp. enterica serovar Abortusequi is a major pathogen in horse and donkey herds, causing abortion in pregnant equids and resulting in enormous economic losses. A rapid and reliable method is urgently needed to detect S. Abortusequi in herds where the disease is suspected. To achieve this goal, a TaqMan-based real-time PCR assay targeting the gene for the flagellin protein phase 2 antigen FljB was developed. This real-time PCR assay had high specificity, sensitivity, and reproducibility. The detection limit of the assay was 30 copies/µL of standard plasmid and 10 CFU/µL of bacterial DNA. Furthermore, 540 clinical samples, including 162 tissue, 192 plasma, and 186 vaginal swab samples collected between 2018 and 2021 in China, were tested to assess the performance of the developed assay. Compared to the gold standard method of bacterial isolation, the real-time PCR assay exhibited 100% positive agreement for all tissue, plasma and vaginal swab tests. Additionally, this assay detected DNA from S. Abortusequi from 56.7% (34/60) culture-negative tissue and 22.9% (41/179) culture-negative vaginal swab samples from infected equids. Receiver operating characteristic analysis demonstrated that the results of the developed real-time PCR assays were in significant agreement with those of the culture method. The real-time PCR assay can be completed within 45 min of extraction of DNA from samples. Our results show that this assay could serve as a reliable tool for the rapid detection of S. Abortusequi in tissue, plasma, and vaginal swab clinical samples.


Assuntos
Salmonelose Animal , Salmonella enterica , Gravidez , Feminino , Animais , Cavalos/genética , Salmonella enterica/genética , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Salmonelose Animal/diagnóstico , Salmonelose Animal/microbiologia , Salmonella/genética , DNA Bacteriano/genética , Sensibilidade e Especificidade
5.
Appl Microbiol Biotechnol ; 107(10): 3305-3317, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37039847

RESUMO

Equine infectious anemia (EIA) is an important viral disease characterized by persistent infection in equids worldwide. Most EIA cases are life-long virus carriers with low antibody reactions and without the appearance of clinical symptoms. A serological test with high sensitivity and specificity is required to detect inapparent infection. In this study, a B-cell common epitope-based blocking ELISA (bELISA) was developed using a monoclonal antibody together with the EIAV p26 protein labelled with HRP. The test has been evaluated against the standard and with field serum samples globally. This bELISA test can be completed within 75 min, and the sensitivity is higher than those of either the AGID or one commercial cELISA kit. This bELISA assay was 8-16 times more analytically sensitive than AGID, and 2 to 4 times more analytically sensitive than one cELISA kit by testing three sera from the USA, Argentina, and China, respectively. The 353 serum samples from Argentina were tested, in comparison with AGID, the diagnostic sensitivity and specificity of our bELISA assay were 100% (154/154) and 97.0% (193/199), respectively, and the accuracy of the bELISA test was 98.3%. The bELISA test developed in this study is a rapid, sensitive, specific method for the detection of EIAV infection, and could be a promising candidate for use in the monitoring of the EIA epidemic worldwide. KEY POINTS: • A universal epitope-based blocking enzyme-linked immunosorbent assay (bELISA) was developed for detection of antibodies to EIAV. • The bELISA assay can be used to test EIAV serum samples from different regions of the world including North America, South America, Europe, and Asia. • The bELISA assay was evaluated in three different international labs and showed a better performance than other commercial kits.


Assuntos
Anemia Infecciosa Equina , Vírus da Anemia Infecciosa Equina , Cavalos , Animais , Anemia Infecciosa Equina/diagnóstico , Anticorpos Antivirais , Ensaio de Imunoadsorção Enzimática/veterinária , Ensaio de Imunoadsorção Enzimática/métodos , Testes Sorológicos/veterinária , Epitopos de Linfócito B , Sensibilidade e Especificidade
6.
Biotechnol Lett ; 42(1): 115-124, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31691164

RESUMO

OBJECTIVE: To thoroughly characterize the Pylb promoter and identify the elements that affect the promoter activity. RESULT: The sequences flanking the - 35 and - 10 box of the Pylb promoter were divided into six segments, and six random-scanning mutant promoter libraries fused to an enhanced green fluorescent protein EGFP were made and analyzed by flow cytometry. Our results showed that the four nucleotides flanking the - 35 box could mostly influence the promoter activity, and this influence was related to the GC content. The promoters mutated in these regions were successfully used for expressing the gene ophc2 encoding organophosphorus hydrolase (OPHC2) and the gene katA encoding catalase (KatA). CONCLUSION: Our work identified and characterized the sequence signatures of the Pylb promoter that could tune the promoter strength, providing further information for the potential application of this promoter. Meanwhile, the sequence signatures have the potential to be used for tuning gene expression in enzyme production, metabolic engineering, and synthetic biology.


Assuntos
Bacillus subtilis/genética , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Fusão Gênica Artificial , Arildialquilfosfatase/análise , Arildialquilfosfatase/genética , Bacillus subtilis/metabolismo , Catalase/análise , Catalase/genética , Análise Mutacional de DNA , Genes Reporter , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/genética
7.
Protein Expr Purif ; 149: 23-30, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29678736

RESUMO

In the previous study, the results on two interesting egfp genes indicated that the expressed eGFP production of egfp-codon containing multiple rare codons was 2.3-fold than that of egfp-genscript with mainly high-frequency-usage codons. Therefore, the rare codons also play important roles for the functional expression of genes and it is interesting to know which rare codons in the egfp affect the functional expression of eGFP. In this study, the structure-guided SCHEMA recombination method and site-specific mutagenesis were proposed to detect the contribution of the rare codons on the functional expression of eGFP. The 12 chimeric egfps were generated from egfp-codon and egfp-genscript by the software SCHEMA. The results indicated that it was the rare codons in the C-terminal coding region (residues from 147 to 239) of eGFP resulting in the higher expression levels in Escherichia coli. The single and multiple point mutations also indicated that the presence of rare codons in 3' coding regions of egfp could enhance the functional expression of eGFP in E. coli. Therefore, the gene sequence on the C-terminal could also affect its functional expression and the strategy of substituting rare codons into coding sequences might be an effective method for increasing heterologous proteins in the host.


Assuntos
Códon/genética , Proteínas de Fluorescência Verde/genética , Proteínas Recombinantes/genética , Escherichia coli , Regulação Bacteriana da Expressão Gênica , Proteínas de Fluorescência Verde/biossíntese , Mutagênese Sítio-Dirigida , Fases de Leitura Aberta , Proteínas Recombinantes/biossíntese
8.
Int J Mol Sci ; 19(12)2018 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-30518113

RESUMO

In the natural host, most of the synonymous codons of a gene have been evolutionarily selected and related to protein expression and function. However, for the design of a new gene, most of the existing codon optimization tools select the high-frequency-usage codons and neglect the contribution of the low-frequency-usage codons (rare codons) to the expression of the target gene in the host. In this study, we developed the method Presyncodon, available in a web version, to predict the gene code from a protein sequence, using built-in evolutionary information on a specific expression host. The synonymous codon-usage pattern of a peptide was studied from three genomic datasets (Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae). Machine-learning models were constructed to predict a selection of synonymous codons (low- or high-frequency-usage codon) in a gene. This method could be easily and efficiently used to design new genes from protein sequences for optimal expression in three expression hosts (E. coli, B. subtilis, and S. cerevisiae). Presyncodon is free to academic and noncommercial users; accessible at http://www.mobioinfor.cn/presyncodon_www/index.html.


Assuntos
Bacillus subtilis/genética , Códon/genética , Escherichia coli/genética , Evolução Molecular , Regulação da Expressão Gênica , Internet , Saccharomyces cerevisiae/genética , Reprodutibilidade dos Testes
9.
Appl Microbiol Biotechnol ; 100(24): 10531-10542, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27660181

RESUMO

The equine infectious anemia virus (EIAV) capsid protein (p26) is one of the major immunogenic proteins during EIAV infection and is widely used for the detection of EIAV antibodies in horses. However, few reports have described the use of EIAV-specific monoclonal antibodies (MAbs) in etiological and immunological detection. Previously, we developed an antigen capture enzyme-linked immunosorbent assay (AC-ELISA) for the quantification of the EIAV p26 protein level. However, the epitopes recognized by the MAbs were not identified, and the utilization of the MAbs needs to be evaluated. In this study, we characterized two monoclonal antibodies (9H8 and 1G11 MAbs) against EIAV p26. Two B-cell epitopes are located in amino acid residues, 73NLDKIAEE81 (HE) and 199KNAMRHLRPEDTLEEKMYAC218 (GE) for the 9H8 and 1G11 MAbs, respectively. The 1G11 epitope (GE) varied among viruses isolated worldwide but can be recognized by anti-EIAV sera from different regions, including China, the USA, and Argentina. Meanwhile, 1G11 MAb could react with the mutants of almost all the EIAV strains. Furthermore, we found that the histidine at position 204 (H204), leucine at position 205 (L205), and aspartic acid at position 209 (D209) of EIAV p26 individually played pivotal roles in binding with the 1G11 MAb. Our results revealed that the GE peptide might be a common B-cell binding epitope of EIAV antibodies. This is also the first report to identify a broad-spectrum monoclonal antibody (1G11) against p26 of EIAV. These findings may provide a useful basis for the development of new diagnostic assays for EIAV.


Assuntos
Mapeamento de Epitopos , Epitopos de Linfócito B/imunologia , Vírus da Anemia Infecciosa Equina/imunologia , Proteínas do Core Viral/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Argentina , China , Vírus da Anemia Infecciosa Equina/isolamento & purificação , Estados Unidos
10.
Microb Cell Fact ; 14: 123, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26310666

RESUMO

BACKGROUND: Although Pichia pastoris has been successfully used to produce various recombinant heterologous proteins, the efficiency varies. In this study, we used methyl parathion hydrolase (MPH) from Ochrobactrum sp. M231 as an example to study the effect of protein amino acid sequence on secretion from P. pastoris. RESULTS: The results indicated that the protein N-terminal sequence, the endoplasmic reticulum (ER) retention signal (KKXX) at the protein C-terminus, and the acidic stability of the protein could affect its secretion from P. pastoris. Mutations designed based on these sequence features markedly improved secretion from P. pastoris. In addition, we found that the secretion properties of a protein can be cumulative when all of the above strategies are combined. The final mutant (CHBD-DQR) designed by combining all of the strategies greatly improved secretion and the secreted MPH activity of CHBD-DQR was enhanced up to 195-fold compared with wild-type MPH without loss of catalytic efficiency. CONCLUSIONS: These results demonstrate that the secretion of heterologous proteins from P. pastoris could be improved by combining changes in multiple protein sequence features.


Assuntos
Monoéster Fosfórico Hidrolases/metabolismo , Pichia/metabolismo , Dosagem de Genes , Engenharia Genética , Organismos Geneticamente Modificados , Pichia/genética , Sinais Direcionadores de Proteínas , RNA Mensageiro/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Análise de Sequência de Proteína
11.
J Virol ; 87(4): 2193-205, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23221562

RESUMO

As the most abundant liver-specific microRNA, miR-122 is involved in diverse aspects of hepatic function and neoplastic transformation. Our previous study showed that miR-122 levels are significantly decreased in hepatitis B virus (HBV)-infected patients, which may facilitate viral replication and persistence (S. Wang, L. Qiu, X. Yan, W. Jin, Y. Wang, L. Chen, E. Wu, X. Ye, G. F. Gao, F. Wang, Y. Chen, Z. Duan, and S. Meng, Hepatology 55:730-741, 2012). Loss of miR-122 expression in patients with hepatitis B enhances hepatitis B virus replication through cyclin G1-modulated P53 activity.). In this study, we provide evidence that all HBV mRNAs harboring an miR-122 complementary site act as sponges to bind and sequester endogenous miR-122, indicating that the highly redundant HBV transcripts are involved in HBV-mediated miR-122 suppression. We next identified pituitary tumor-transforming gene 1 (PTTG1) binding factor (PBF) as a target of miR-122 and demonstrated that HBV replication causes an obvious increase in PBF levels. Furthermore, we observed that the miR-122 levels were decreased and PBF was upregulated in chronic hepatitis B (CHB) and hepatocellular carcinoma (HCC). Overexpression and knockdown studies both revealed that PBF enhances proliferation and invasion of HCC cells, and silencing PBF resulted in a dramatic reduction of HCC tumor growth in vivo. Mechanistic analysis demonstrated that PBF interacts with PTTG1 and facilitates PTTG1 nuclear translocation, subsequently increasing its transcriptional activities. Therefore, we identified a novel HBV mRNA-miR-122-PBF regulatory pathway that facilitates malignant hepatocyte growth and invasion in CHB which may contribute to CHB-induced HCC development and progression. Our work underscores the reciprocal interplay of host miRNA sequestration and depletion by viral mRNAs, which may contribute to chronic-infection-related cancer.


Assuntos
Carcinoma Hepatocelular/virologia , Vírus da Hepatite B/patogenicidade , Hepatite B Crônica/virologia , Proteínas de Membrana/biossíntese , MicroRNAs/metabolismo , RNA Mensageiro/metabolismo , RNA Viral/metabolismo , Adulto , Idoso , Animais , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Neoplasias Hepáticas/virologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade
12.
Antioxidants (Basel) ; 13(4)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38671834

RESUMO

The administration of NAD+ precursors is a potential approach to protect against liver damage and metabolic dysfunction. However, the effectiveness of different NAD+ precursors in alleviating metabolic disorders is still poorly elucidated. The current study was performed to compare the effectiveness of four different NAD+ precursors, including nicotinic acid (NA), niacinamide (NAM), nicotinamide riboside (NR), and nicotinamide mononucleotide (NMN) in alleviating high-glucose-induced injury to hepatocytes in a fish model, Megalobrama amblycephala. An in vitro high-glucose model was successfully established to mimic hyperglycemia-induced damage to the liver, which was evidenced by the reduced cell viability, the increased transaminase activity, and the depletion of cellular NAD+ concentration. The NAD+ precursors all improved cell viability, with the maximal effect observed in NR, which also had the most potent NAD+ boosting capacity and a significant Sirt1/3 activation effect. Meanwhile, NR presented distinct and superior effects in terms of anti-oxidative stress, inflammation inhibition, and anti-apoptosis compared with NA, NAM, and NMN. Furthermore, NR could effectively benefit glucose metabolism by activating glucose transportation, glycolysis, glycogen synthesis and the pentose phosphate pathway, as well as inhibiting gluconeogenesis. Moreover, an oral gavage test confirmed that NR presented the most potent effect in increasing hepatic NAD+ content and the NAD+/NADH ratio among four NAD+ precursors. Together, the present study results demonstrated that NR is most effective in attenuating the high-glucose-induced injury to hepatocytes in fish compared to other NAD+ precursors.

13.
Adv Mater ; : e2412653, 2024 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-39422373

RESUMO

Covalent organic frameworks (COFs) as a new type of photocatalysts have shown unique advantages in visible-light-driven hydrogen evolution, while the reported overall water-splitting systems are still very rare among various COF-based photocatalysts. Herein, two COFs are integrated to construct a type of organic S-scheme heterojunction for improved overall water splitting. In this system, TpBpy-COF and COF-316 serve as H2- and O2-evolving components, respectively, which are combined through π-π interaction between conjugated aromatic rings. By introducing ultra-small Pt nanoparticles (NPs) into the pores of the TpBpy-COF nanosheets (NS), the resultant COF-316/Pt@TpBpy-COF NS heterostructure achieves extremely high H2 and O2 evolution rates of 220.4 and 110.2 µmol g-1 h-1, respectively, under visible light irradiation (λ ≥ 420 nm). The results of transient absorption spectra (TAS) and photoelectronic measurements indicate that the organic heterojunction interface notably facilitates the separation and transfer of photogenerated electron-hole pairs. Further, theoretical calculations and in situ experiments confirm the spontaneous formation of the COF/COF heterojunction interface and the active sites for overall water splitting.

14.
Dalton Trans ; 53(34): 14325-14332, 2024 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-39136079

RESUMO

Modulating the photogenerated electrons of CeO2 to activate O2 and efficiently photocatalytic degradation of chlorophenols is a highly desired goal. Herein, we have successfully fabricated an FePc/CeO2 heterojunction through H-bond induced assembly. The photocatalytic degradation of 2,4-DCP by the amount-optimized FePc/CeO2 nanocomposite was improved by 3 times compared with that by pure CeO2. By means of electron paramagnetic resonance (EPR) and single wavelength photocurrent spectroscopy, it is confirmed that the excellent photocatalytic performance is mainly attributed to the formation of the Z-scheme heterojunction, which promotes charge separation and transfer, and the introduction of FePc broadens the visible light absorption range of the heterojunction. Moreover, O2 temperature-programmed-desorbed curves and electrochemical O2 reduction measurement results demonstrate that the single Fe-N4(II) site in FePc is more conducive to promoting O2 activation than that of other metal phthalocyanines. Based on in situ FT-IR and liquid chromatography-tandem mass spectrometry (LC-MS/MS), a possible reaction pathway of 2,4-DCP degradation was proposed. This study provides a novel strategy for preparing CeO2 based Z-scheme heterojunctions with abundant monoatomic sites for pollutant degradation.

15.
Dalton Trans ; 53(6): 2534-2540, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38234156

RESUMO

Designing photocatalysts with efficient charge separation and electron transport capabilities to achieve efficient visible-driven hydrogen production remains a challenge. Herein, 2D-2D conductive metal-organic framework/g-C3N4 heterojunctions were successfully prepared by an in situ assembly. Compared to pristine g-C3N4, the ratio-optimized Ni-CAT-1/g-C3N4 exhibits approximately 3.6 times higher visible-light H2 production activity, reaching 14 mmol g-1. Through investigations using time-resolved photoluminescence, surface photovoltage, and wavelength-dependent photocurrent action spectroscopies, it is determined that the improved photocatalytic performance is attributed to enhanced charge transfer and separation, specifically the efficient transfer of excited high-energy-level electrons from g-C3N4 to Ni-CAT in the heterojunctions. Furthermore, the high electrical conductivity of Ni-CAT enables rapid electron transport, contributing to the overall enhanced performance. This work provides a feasible strategy to construct efficient dimension-matched g-C3N4-based heterojunction photocatalysts with high-efficiency charge separation for solar-driven H2 production.

16.
Comput Biol Med ; 181: 109076, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39216405

RESUMO

BACKGROUND: Knowledge feature (KF) with clear physiological significance of photoplethysmography are widely used in predicting blood pressure. However, KF primarily focus on local information of photoplethysmography, which may struggle to capture the overall characteristics. METHODS: Firstly, functional data analysis (FDA) was introduced to extract two types of data feature (DF). Furthermore, data-knowledge co-driven feature (DKCF) was proposed by combining FDA and constraints of KF. Finally, random forest, ada boost, gradient boosting, support vector machine and deep neural network were adopted, to compare the abilities of KF, DFs and DKCF in predicting blood pressure with two datasets (A published dataset and a self-collected dataset). RESULTS: Under the premise of extracting only 9 features, the average mean absolute errors (MAE) of systolic blood pressure (SBP) and diastolic blood pressure (DBP) obtained by DKCF are both the smallest in dataset 1. In dataset 2, DKCF acquires the smallest MAE in predicting SBP and obtains the second smallest MAE in predicting DBP. CONCLUSIONS: The results demonstrate that low-dimensional DKCF of photoplethysmography is closely correlated with blood pressure, which may serve as an important indicator for health assessment.


Assuntos
Pressão Sanguínea , Fotopletismografia , Humanos , Fotopletismografia/métodos , Pressão Sanguínea/fisiologia , Masculino , Feminino , Determinação da Pressão Arterial/métodos , Adulto , Máquina de Vetores de Suporte , Redes Neurais de Computação , Pessoa de Meia-Idade
17.
Nat Commun ; 15(1): 8818, 2024 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-39394216

RESUMO

Rational design of robust photocatalytic systems to direct capture and in-situ convert diluted CO2 from flue gas is a promising but challenging way to achieve carbon neutrality. Here, we report a new type of host-guest photocatalysts by integrating CO2-enriching ionic liquids and photoactive metal-organic frameworks PCN-250-Fe2M (M = Fe, Co, Ni, Zn, Mn) for artificial photosynthetic diluted CO2 reduction in gas-solid phase. As a result, [Emim]BF4(39.3 wt%)@PCN-250-Fe2Co exhibits a record high CO2-to-CO reduction rate of 313.34 µmol g-1 h-1 under pure CO2 atmosphere and 153.42 µmol g-1 h-1 under diluted CO2 (15%) with about 100% selectivity. In scaled-up experiments with 1.0 g catalyst and natural sunlight irradiation, the concentration of pure and diluted CO2 (15%) could be significantly decreased to below 85% and 10%, respectively, indicating its industrial application potential. Further experiments and theoretical calculations reveal that ionic liquids not only benefit CO2 enrichment, but also form synergistic effect with Co2+ sites in PCN-250-Fe2Co, resulting in a significant reduction in Gibbs energy barrier during the rate-determining step of CO2-to-CO conversion.

18.
Sci China Life Sci ; 67(1): 96-112, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37698691

RESUMO

Chromatin accessibility remodeling driven by pioneer factors is critical for the development of early embryos. Current studies have illustrated several pioneer factors as being important for agricultural animals, but what are the pioneer factors and how the pioneer factors remodel the chromatin accessibility in porcine early embryos is not clear. By employing low-input DNase-seq (liDNase-seq), we profiled the landscapes of chromatin accessibility in porcine early embryos and uncovered a unique chromatin accessibility reprogramming pattern during porcine preimplantation development. Our data revealed that KLF4 played critical roles in remodeling chromatin accessibility in porcine early embryos. Knocking down of KLF4 led to the reduction of chromatin accessibility in early embryos, whereas KLF4 overexpression promoted the chromatin openness in porcine blastocysts. Furthermore, KLF4 deficiency resulted in mitochondrial dysfunction and developmental failure of porcine embryos. In addition, we found that overexpression of KLF4 in blastocysts promoted lipid droplet accumulation, whereas knockdown of KLF4 disrupted this process. Taken together, our study revealed the chromatin accessibility dynamics and identified KLF4 as a key regulator in chromatin accessibility and cellular metabolism during porcine preimplantation embryo development.


Assuntos
Cromatina , Desenvolvimento Embrionário , Suínos , Animais , Desenvolvimento Embrionário/genética , Cromatina/genética , Cromatina/metabolismo , Blastocisto/metabolismo , Cromossomos
19.
Cell Rep ; 43(6): 114372, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38878289

RESUMO

Emerging evidence highlights the regulatory role of paired-like (PRD-like) homeobox transcription factors (TFs) in embryonic genome activation (EGA). However, the majority of PRD-like genes are lost in rodents, thus prompting an investigation into PRD-like TFs in other mammals. Here, we showed that PRD-like TFs were transiently expressed during EGA in human, monkey, and porcine fertilized embryos, yet they exhibited inadequate expression in their cloned embryos. This study, using pig as the research model, identified LEUTX as a key PRD-like activator of porcine EGA through genomic profiling and found that LEUTX overexpression restored EGA failure and improved preimplantation development and cloning efficiency in porcine cloned embryos. Mechanistically, LEUTX opened EGA-related genomic regions and established histone acetylation via recruiting acetyltransferases p300 and KAT2A. These findings reveal the regulatory mechanism of LEUTX to govern EGA in pigs, which may provide valuable insights into the study of early embryo development for other non-rodent mammals.


Assuntos
Genoma , Técnicas de Transferência Nuclear , Animais , Suínos , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética , Desenvolvimento Embrionário/genética , Embrião de Mamíferos/metabolismo , Humanos , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Acetilação , Clonagem de Organismos/métodos , Histonas/metabolismo , Blastocisto/metabolismo
20.
Appl Microbiol Biotechnol ; 97(7): 2997-3006, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23001009

RESUMO

Good protein thermostability is very important for the protein application. In this report, we propose a strategy which contained a prediction method to select residues related to protein thermal stability, but not related to protein function, and an experiment method to screen the mutants with enhanced thermostability. The prediction strategy was based on the calculated site evolutionary entropy and unfolding free energy difference between the mutant and wild-type (WT) methyl parathion hydrolase enzyme from Ochrobactrum sp. M231 [Ochr-methyl parathion hydrolase (MPH)]. As a result, seven amino acid sites within Ochr-MPH were selected and used to construct seven saturation mutagenesis libraries. The results of screening these libraries indicated that six sites could result in mutated enzymes exhibiting better thermal stability than the WT enzyme. A stepwise evolutionary approach was designed to combine these selected mutants and a mutant with four point mutations (S274Q/T183E/K197L/S192M) was selected. The Tm and T50 of the mutant enzyme were 11.7 and 10.2 °C higher, respectively, than that of the WT enzyme. The success of this design methodology for Ochr-MPH suggests that it was an efficient strategy for enhancing protein thermostability and suitable for protein engineering.


Assuntos
Metil Paration/metabolismo , Ochrobactrum/enzimologia , Monoéster Fosfórico Hidrolases/química , Monoéster Fosfórico Hidrolases/metabolismo , Engenharia de Proteínas/métodos , Simulação por Computador , Análise Mutacional de DNA , Estabilidade Enzimática , Modelos Moleculares , Mutagênese Sítio-Dirigida , Proteínas Mutantes/química , Proteínas Mutantes/isolamento & purificação , Proteínas Mutantes/metabolismo , Monoéster Fosfórico Hidrolases/isolamento & purificação , Conformação Proteica , Estabilidade Proteica , Temperatura
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