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1.
Cancer Cell ; 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-39094560

RESUMO

Neoadjuvant chemoradiotherapy (NACRT) was the standard treatment for patients with locally advanced rectal cancer (LARC) with proficient mismatch repair (pMMR) proteins. In this randomized phase 2 trial (ClinicalTrial.gov: NCT04304209), 134 pMMR LARC patients were randomly (1:1) assigned to receive NACRT or NACRT and the programmed cell death protein 1 (PD-1) antibody sintilimab. As the primary endpoint, the total complete response (CR) rate is 26.9% (18/67, 95% confidence interval [CI] 16.0%-37.8%) and 44.8% (30/67, 95% CI 32.6%-57.0%) in the control and experimental arm, respectively, with significant difference (p = 0.031 for chi-squared test). Response ratio is 1.667 (95% CI 1.035-2.683). Immunohistochemistry shows PD-1 ligand 1 (PD-L1) combined positive score is associated with the synergistic effect. The safety profile is similar between the arms. Adding the PD-1 antibody sintilimab to NACRT significantly increases the CR rate in pMMR LARC, with a manageable safety profile. PD-L1 positivity may help identify patients who might benefit most from the combination therapy.

2.
Adv Sci (Weinh) ; : e2402329, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39120980

RESUMO

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer and its prognosis remains poor. Although growing numbers of studies have verified the involvement of circular RNAs (circRNAs) in various cancer types, their specific functions in ICC remain elusive. Herein, a circRNA, circUGP2 is identified by circRNA sequencing, which is downregulated in ICC tissues and correlated with patients' prognosis. Moreover, circUGP2 overexpression suppresses tumor progression in vitro and in vivo. Mechanistically, circUGP2 functions as a transcriptional co-activator of PURB over the expression of ADGRB1. It can also upregulate ADGRB1 expression by sponging miR-3191-5p. As a result, ADGRB1 prevents MDM2-mediated p53 polyubiquitination and thereby activates p53 signaling to inhibit ICC progression. Based on these findings, circUGP2 plasmid is encapsulated into a lipid nanoparticle (LNP) system, which has successfully targeted tumor site and shows superior anti-tumor effects. In summary, the present study has identified the role of circUGP2 as a tumor suppressor in ICC through regulating ADGRB1/p53 axis, and the application of LNP provides a promising translational strategy for ICC treatment.

3.
Chem Biol Drug Des ; 104(2): e14610, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39160642

RESUMO

NADPH oxidases (NOXs) are the sole enzyme in the human body that can directly produce reactive oxygen species. Recent studies have shown that NOXs is a very promising target for the treatment of diabetic nephropathy (DN). Here, a series of quinoline(quinolinone) derivatives have been designed based on pharmacophore strategy, synthesized and evaluated. Among them, 19d exhibits potent antiproliferative and NOXs inhibitory activities, and is worthy for further investigation.


Assuntos
Desenho de Fármacos , Inibidores Enzimáticos , NADPH Oxidases , Quinolinas , Quinolonas , Humanos , NADPH Oxidases/metabolismo , NADPH Oxidases/antagonistas & inibidores , Quinolinas/química , Quinolinas/farmacologia , Quinolinas/síntese química , Quinolonas/química , Quinolonas/farmacologia , Quinolonas/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/síntese química , Relação Estrutura-Atividade , Proliferação de Células/efeitos dos fármacos , Linhagem Celular Tumoral
4.
Sci Rep ; 14(1): 18964, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39152170

RESUMO

Accurately and quickly estimating the soil organic carbon (SOC) content is crucial in the monitoring of global carbon. Environmental variables play a significant role in improving the accuracy of the SOC content estimation model. This study focuses on modeling methodologies and environmental variables, which significantly influence the SOC content estimation model. The modeling methods used in this research comprise multiple linear regression (MLR), partial least squares regression (PLSR), random forest, and support vector machines (SVM). The analyzed environmental variables include terrain, climate, soil, and vegetation cover factors. The original spectral reflectance (OSR) of Landsat 5 TM images and the spectral reflectivity after the derivative processing were combined with the above environmental variables to estimate SOC content. The results showed that: (1) The SOC content can be efficiently estimated using the OSR of Landsat 5 TM, however, the derived processing method cannot significantly improve the estimation accuracy. (2) Environmental variables can effectively improve the accuracy of SOC content estimation, with climate and soil factors producing the most significant improvements. (3) Machine learning modeling methods provide better estimation accuracy than MLR and PLSR, especially the SVM model which has the highest accuracy. According to our observations, the best estimation model in the study area was the "OSR + SVM" model (R2 = 0.9590, RMSE = 13.9887, MAE = 10.8075), which considered four environmental factors. This study highlights the significance of environmental variables in monitoring SOC content, offering insights for more precise future SOC assessments. It also provides crucial data support for soil health monitoring and sustainable agricultural development in the study area.

7.
Front Pharmacol ; 15: 1337179, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38974037

RESUMO

Background: The effectiveness and safety of using Brucea javanica oil (BJO) in combination with Transarterial Chemoembolization (TACE) for liver cancer treatment are subjects of debate. This study aims to assess the comparative effectiveness and safety of BJO-assisted TACE versus TACE alone and quantifies the differences between these two treatment methods. Methods: A systematic search was conducted in multiple databases including PubMed, Cochrane, CNKI, and Wanfang, until 1 July 2023. Meta-analysis was conducted, and the results were presented as mean difference (MD), risk ratio (RR), and 95% confidence intervals (CI). Results: The search yielded 11 RCTs, with a combined sample size of 1054 patients. Meta-analysis revealed that BJO-assisted TACE exhibited superior outcomes compared to standalone TACE. Specific data revealed that BJO-assisted TACE improves clinical benefit rate by 22% [RR = 1.22, 95% CI (1.15, 1.30)], increases the number of people with improved quality of life by 32%, resulting in an average score improvement of 9.53 points [RR = 1.32, 95% CI (1.22, 1.43); MD = 9.53, 95% CI (6.95, 12.10)]. Furthermore, AFP improvement rate improved significantly by approximately 134% [RR = 2.34, 95% CI (1.58, 3.46)], accompanied by notable improvements in liver function indicators, with an average reduction of 27.19 U/L in AST [MD = -27.19, 95% CI (-40.36, -14.02)], 20.77 U/L in ALT [MD = -20.77, 95% CI (-39.46, -2.08)], 12.17 µmol/L in TBIL [MD = -12.17, 95% CI (-19.38, -4.97)], and a decrease of 43.72 pg/mL in VEGF [MD = -43.72, 95% CI (-63.29, -24.15)]. Most importantly, there was a 29% reduction in the occurrence of adverse reactions [RR = 0.71, 95% CI (0.60, 0.84)]. Conclusion: These findings indicate that BJO-assisted TACE may be considered as a potentially beneficial treatment option for liver cancer patients when compared to standalone TACE. It appears to contribute to improved treatment outcomes, enhanced quality of life, and potentially reduced adverse reactions, suggesting it warrants further investigation as a promising approach for liver cancer treatment. Systematic Review Registration: identifier CRD42023428948.

8.
Genome Biol ; 25(1): 164, 2024 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-38915088

RESUMO

Spatial transcriptomics has transformed our ability to study tissue complexity. However, it remains challenging to accurately dissect tissue organization at single-cell resolution. Here we introduce scHolography, a machine learning-based method designed to reconstruct single-cell spatial neighborhoods and facilitate 3D tissue visualization using spatial and single-cell RNA sequencing data. scHolography employs a high-dimensional transcriptome-to-space projection that infers spatial relationships among cells, defining spatial neighborhoods and enhancing analyses of cell-cell communication. When applied to both human and mouse datasets, scHolography enables quantitative assessments of spatial cell neighborhoods, cell-cell interactions, and tumor-immune microenvironment. Together, scHolography offers a robust computational framework for elucidating 3D tissue organization and analyzing spatial dynamics at the cellular level.


Assuntos
Aprendizado de Máquina , Análise de Célula Única , Análise de Célula Única/métodos , Animais , Humanos , Camundongos , Biologia Computacional/métodos , Comunicação Celular , Transcriptoma , Microambiente Tumoral
9.
Front Oncol ; 14: 1309681, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38746684

RESUMO

Objectives: In this study, we compared the dynamic changes in body composition during XELOX/SOX chemotherapy in patients with gastric cancer. Furthermore, we investigated the potential impact of these changes on the occurrence of toxic side effects. Methods: Patients with gastric cancer who received adjuvant or first-line XELOX/SOX chemotherapy between January 2020 and June 2023 were enrolled. The Brief Conghua Scale was used to assess energy intake, and nutritional management was carried out with reference to the Chinese Guidelines for Nutritional Therapy of Cancer 2020. The NRS 2002 Nutritional Risk Screening Scale, PG-SGA scale, bioelectrical impedance analysis, and dynamic changes in lumbar 3 vertebral skeletal muscle index were compared between baseline and post-chemotherapy in the study. The neutropenia was evaluated using the Common Terminology Criteria for Adverse Events V.5.0, developed by the National Institutes of Health. Results: Dynamic follow-up was completed in 39 cases, with a mean follow-up time of 117.62 ± 43.38 days. The incidence of sarcopenia increased significantly after chemotherapy, escalating from 46.2% to 51.3%. After chemotherapy, the mean L3SMI decreased from 36.00 cm2/m2 to 34.99 cm2/m2. Furthermore, when compared to pre-chemotherapy values, the body composition indexes body mass index (BMI), SL3, fat mass free index (FFMI), lean body mass (LBM), and body surface area (BSA) were significantly reduced after chemotherapy. Regardless of baseline or post-chemotherapy status, the incidence of grade ≥ 3 neutropenia was significantly higher in the sarcopenia group than in the non-sarcopenia group. Furthermore, when the skeletal muscle index decreased during chemotherapy, the incidence of grade ≥ 3 neutropenia was significantly higher in both the sarcopenia and non-sarcopenia groups compared to baseline. When the incidence of grade ≥ 3 neutropenia in the post-chemotherapy sarcopenia group was compared to baseline status, the increase was significantly higher in the sarcopenia group than in the maintenance/increase group. Conclusions: Skeletal muscle mass decreased progressively during XELOX/SOX chemotherapy in gastric cancer patients, followed by a higher incidence of grade ≥ 3 neutropenia.

10.
N Biotechnol ; 82: 85-91, 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-38777090

RESUMO

Suppressor tRNAs, notable for their capability of reading through the stop codon while maintaining normal peptide synthesis, are promising in treating diseases caused by premature termination codons (PTC). However, the lack of effective engineering methods for suppressor tRNAs has curtailed their application potential. Here, we introduce a directed evolution technology that employs phage-assisted continuous evolution (PACE), combined with gradient biosensors featuring various PTCs in the M13 gene III. Utilizing this novel methodology, we have successfully evolved tRNATrp (UGG) reading through the UGA stop codon in Escherichia coli. Massively parallel sequencing revealed that these mutations predominantly occurred in the anticodon loop. Finally, two suppressor tRNATrp (UGA) mutants exhibited over fivefold increases in readthrough efficiency.


Assuntos
Escherichia coli , RNA de Transferência , Escherichia coli/genética , RNA de Transferência/genética , Evolução Molecular Direcionada , Códon de Terminação/genética , Mutação , Bacteriófago M13/genética
11.
Sheng Li Xue Bao ; 76(1): 1-11, 2024 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-38444127

RESUMO

Perineuronal nets (PNNs) are specialized extracellular matrix (ECM) structures present in the central nervous system (CNS) and have been identified as significant regulators of developmental plasticity in the developing cortex. PNNs are particularly enriched in the cortex surrounding parvalbumin-expressing (PV+) cells. A growing body of evidence suggests that the abnormalities in PV+ neurons and PNNs are associated with various neurological disorders, including schizophrenia, which is a neurodevelopmental defect disease. The N-methyl-D-aspartate receptor (NMDAR) selective antagonist is frequently employed to establish animal models of schizophrenia in laboratory settings. The crucial involvement of GluN2B-containing NMDARs in the development of CNS has been extensively established. However, the role of GluN2B in the pathophysiology of schizophrenia has yet to be thoroughly investigated. The present study inhibited GluN2B function through intraperitoneal infusion of the GluN2B selective antagonist ifenprodil into juvenile mice aged 3-4 weeks, followed by the administration of social stress when these mice reached 9 weeks of age. Then, immunofluorescence staining was employed to examine the changes in the PNNs and PV+ cells, an acoustic startle and prepulse inhibition test was used to detect activities of the PV+ cells, and Western blot was used to quantify the protein expression levels of GluN2A and GluN2B in the prefrontal cortex (PFC). The study revealed that in the PFC of mice subjected to GluN2B antagonist treatment in early life and social stress in adulthood, there was an increase in the number of PV+ cells wrapped by PNNs, and a decrease in the activation of PV+ cells during the prepulse inhibition test, which is an indicator of sensory gating functions, as well as changes in the protein expression levels of GluN2A and GluN2B, which resulted in an increase in the ratio of GluN2A to GluN2B. These aberrations in the mice are comparable to those observed in animal models and patients with schizophrenia. The findings suggest that even a transient hypofunction of GluN2B in early life poses a significant risk for the emergence of schizophrenia symptoms in adulthood.


Assuntos
Receptores de N-Metil-D-Aspartato , Estresse Psicológico , Animais , Humanos , Camundongos , Moléculas de Adesão Celular , Sistema Nervoso Central , Córtex Cerebral , Matriz Extracelular , Proteínas Nucleares
12.
Molecules ; 29(6)2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38542887

RESUMO

Herein, a Sc(OTf)3-catalyzed (3+2) annulation of 2-indolylmethanols with propargylic alcohols is reported. The reaction proceeds via a Friedel-Crafts-type allenylation/5-exo-annulation cascade. In the reaction, 2-indolylmethanol is used as a three-carbon synthon, and propargyl alcohol is used as a two-carbon synthon. This method provides a direct and high-yield pathway for synthetically useful cyclopenta[b]indoles. In general, the method features easily accessible substrates with broad scope and generality, the formation of multiple bonds with high efficiency, and easy scale-up.

13.
Heliyon ; 10(3): e25184, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38322946

RESUMO

Objectives: To investigate the prognostic capacity of baseline 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) metabolic parameters in extranodal natural killer/T-cell lymphoma (ENKTCL), and the influence of relative thresholds (RT) and absolute thresholds (AT) selection on prognostic capacity. Materials and methods: Metabolic tumor volume (MTV)-based parameters were defined using RTs (41 % or 25 % of maximum standardized uptake value [SUVmax]), ATs (SUV 2.5, 3.0, 4.0, or mean liver uptake) in 133 patients. Metabolic parameters were classified into avidity-related parameters (SUVmax, mean SUV [SUVmean], standard deviation of SUV [SUVsd]), volume-related parameters (RT-MTV), and avidity- and volume-related parameters (total lesion glycolysis [TLG] and AT-MTV). The prognostic capacity of the metabolic parameters and the effects of different threshold types (RT vs. AT) were evaluated. Results: All metabolic parameters were moderately associated with prognosis. However, the area under the receiver operating characteristic curve of MTV and TLG was slightly higher than that of avidity-related parameters for predicting 5-year progression-free survival (PFS) (0.614-0.705 vs. 0.563-0.609) and overall survival (OS) (0.670-0.748 vs. 0.562-0.593). Correlations of MTV and avidity-related parameters differed between RTs (r < 0.06, P = 0.324-0.985) and ATs (r 0.56-0.84, P ≤ 0.001). AT-MTV was the optimal predictor for PFS and OS, while RT-TLG was the optimal predictor for PFS, and the combination of RT-MTV with SUVmax was the optimal predictor for OS. Conclusion: The incorporation of volume and avidity significantly improved the prognostic capacity of PET in ENKTCL. Composite parameters that encompassed both avidity and volume were recommended.

14.
Heart Lung ; 65: 19-30, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38377628

RESUMO

BACKGROUND: Tuberculosis (TB) represents a significant global health concern, being the leading cause of mortality from a single infectious agent worldwide. The investigation of TB incidence and epidemiological trends is critical for evaluating the effectiveness of control strategies and identifying ongoing challenges. OBJECTIVES: This study presents the trend in TB incidence across 204 countries and regions over a 30-year period. METHODS: The study utilises data sourced from the Global Burden of Disease (GBD) database. The age cohort model and gender subgroup analysis were employed to estimate the net drift (overall annual percentage change), local drift (age annual percentage change), longitudinal age curve (expected age ratio), and cycle and cohort effect (relative risk of cycle and birth cohort) of TB incidence from 1990 to 2019. This approach facilitates the examination and differentiation of age, period, and cohort effects in TB incidence trends, potentially identifying disparities in TB prevention across different countries. RESULTS: Over the past three decades, a general downward trend in TB incidence has been observed in most countries. However, in 15 of the 204 countries, the overall incidence rate is still on the rise (net drift ≥0.0 %) or stagnant decline (≥-0.5 %). From 1990 to 2019, the net drift of tuberculosis mortality ranged from -2.2 % [95 % confidence interval (CI): -2.33, -2.05] in high Socio-demographic Index (SDI) countries to -1.7 % [95 % CI: -1.81, -1.62] in low SDI countries. In some below-average SDI countries,men in the birth cohort are at a disadvantage and at risk of deterioration, necessitating comprehensive TB prevention and treatment. CONCLUSIONS: While the global incidence of TB has declined, adverse period and cohort effects have been identified in numerous countries, raising questions about the adequacy of TB healthcare provision across all age groups. Furthermore, this study reveals gender disparities in TB incidence.


Assuntos
Carga Global da Doença , Tuberculose , Masculino , Humanos , Incidência , Saúde Global , Tuberculose/epidemiologia , Estudos de Coortes
15.
Int J Mol Sci ; 25(4)2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38396885

RESUMO

The mammalian myocardium grows rapidly during early development due to cardiomyocyte proliferation, which later transitions to cell hypertrophy to sustain the heart's postnatal growth. Although this cell transition in the postnatal heart is consistently preserved in mammalian biology, little is known about the regulatory mechanisms that link proliferation suppression with hypertrophy induction. We reasoned that the production of a micro-RNA(s) could serve as a key bridge to permit changes in gene expression that control the changed cell fate of postnatal cardiomyocytes. We used sequential expression analysis to identify miR205 as a micro-RNA that was uniquely expressed at the cessation of cardiomyocyte growth. Cardiomyocyte-specific miR205 deletion animals showed a 35% increase in heart mass by 3 months of age, with commensurate changes in cell cycle and Hippo pathway activity, confirming miR205's potential role in controlling cardiomyocyte proliferation. In contrast, overexpression of miR205 in newborn hearts had little effect on heart size or function, indicating a complex, probably redundant regulatory system. These findings highlight miR205's role in controlling the shift from cardiomyocyte proliferation to hypertrophic development in the postnatal period.


Assuntos
Coração , MicroRNAs , Miócitos Cardíacos , Animais , Animais Recém-Nascidos , Proliferação de Células/genética , Hipertrofia/metabolismo , Mamíferos , Miócitos Cardíacos/metabolismo , Camundongos
16.
Small Methods ; 8(8): e2301385, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38415955

RESUMO

Sugar substitutes are popular due to their akin taste and low calories. However, excessive use of aspartame and erythritol can have varying effects. While D-allulose is presently deemed a secure alternative to sugar, its excessive consumption is not devoid of cellular stress implications. In this study, the evolution of Escherichia coli Nissle 1917 (EcN) is directed to utilize allulose as sole carbon source through a combination of adaptive laboratory evolution (ALE) and fluorescence-activated droplet sorting (FADS) techniques. Employing whole genome sequencing (WGS) and clustered regularly interspaced short palindromic repeats interference (CRISPRi) in conjunction with compensatory expression displayed those genetic mutations in sugar and amino acid metabolic pathways, including glnP, glpF, gmpA, nagE, pgmB, ybaN, etc., increased allulose assimilation. Enzyme-substrate dynamics simulations and deep learning predict enhanced substrate specificity and catalytic efficiency in nagE A247E and pgmB G12R mutants. The findings evince that these mutations hold considerable promise in enhancing allulose uptake and facilitating its conversion into glycolysis, thus signifying the emergence of a novel metabolic pathway for allulose utilization. These revelations bear immense potential for the sustainable utilization of D-allulose in promoting health and well-being.


Assuntos
Evolução Molecular Direcionada , Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Evolução Molecular Direcionada/métodos , Frutose/metabolismo , Carbono/metabolismo , Mutação , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Sequenciamento Completo do Genoma , Redes e Vias Metabólicas
18.
Cancer Med ; 13(1): e6899, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38180169

RESUMO

This study aimed to predict the 5-year overall survival (OS) benefit of pola-R-CHP versus R-CHOP in the POLARIX trial based on the 2-year event-free survival (EFS) and progression-free survival (PFS) rates in diffuse large B-cell lymphoma (DLBCL). We identified randomized controlled trials (RCT) published before 31 May 2023. The correlation between the logarithmic (log) hazard ratio (HR) for EFS (HREFS) or PFS (HRPFS) and the HR for OS (HROS) was estimated at the trial-level. Correlation analysis was performed between 2-year PFS or EFS and 5-year OS rates at the treatment arm-level. Linear regression models were used to calculate the 5-year OS of pola-R-CHP and R-CHOP. In the included 20 RCTs, a linear correlation between HREFS (r = 0.765) or HRPFS (r = 0.534) and HROS was observed at the trial- level. Two-year EFS (r = 0.918) or 2-year PFS (r = 0.865) correlated linearly with 5-year OS. Linear regression analysis between 2-year EFS/PFS and 5-year OS gave estimated 5-year OS rates between pola-R-CHP and R-CHOP of 6.4% and 6.3%, respectively. Two-year EFS and PFS are feasible early endpoints in patients with DLBCL treated primarily with immunochemotherapy. The pola-R-CHP regimen is expected to improve 5-year OS.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Ciclofosfamida , Doxorrubicina , Linfoma Difuso de Grandes Células B , Prednisona , Intervalo Livre de Progressão , Ensaios Clínicos Controlados Aleatórios como Assunto , Rituximab , Vincristina , Linfoma Difuso de Grandes Células B/mortalidade , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Rituximab/uso terapêutico , Ciclofosfamida/uso terapêutico , Prednisona/uso terapêutico , Vincristina/uso terapêutico , Doxorrubicina/uso terapêutico , Feminino , Masculino , Pessoa de Meia-Idade , Citarabina/uso terapêutico , Anticorpos Monoclonais , Imunoconjugados
20.
Sci Rep ; 13(1): 16053, 2023 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-37749183

RESUMO

A xylanase gene (named xyngmqa) was identified from the metagenomic data of the Gumingquan hot spring (92.5 °C, pH 9.2) in Tengchong City, Yunnan Province, southwest China. It showed the highest amino acid sequence identity (82.70%) to endo-1,4-beta-xylanase from Thermotoga caldifontis. A constitutive expression plasmid (denominated pSHY211) and double-layer plate (DLP) method were constructed for cloning, expression, and identification of the XynGMQA gene. The XynGMQA gene was synthesized and successfully expressed in Escherichia coli DH5α. XynGMQA exhibited optimal activity at 90 °C and pH 4.6, being thermostable by maintaining 100% of its activity after 2 h incubated at 80 °C. Interestingly, its enzyme activity was enhanced by high temperatures (70 and 80 °C) and low pH (3.0-6.0). About 150% enzyme activity was detected after incubation at 70 °C for 20 to 60 min or 80 °C for 10 to 40 min, and more than 140% enzyme activity after incubation at pH 3.0 to 6.0 for 12 h. Hydrolytic products of beechwood xylan with XynGMQA were xylooligosaccharides, including xylobiose (X2), xylotriose (X3), and xylotetraose (X4). These properties suggest that XynGMQA as an extremely thermophilic xylanase, may be exploited for biofuel and prebiotic production from lignocellulosic biomass.


Assuntos
Fontes Termais , China , Metagenoma , Sequência de Aminoácidos , Biocombustíveis , Escherichia coli/genética
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