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1.
Artigo em Inglês | MEDLINE | ID: mdl-35038704

RESUMO

BACKGROUND: Diabetic nephropathy is a common complication of kidneys induced by diabetes and is the main cause of end-stage renal disease. MicroRNA-494-3p was reported to be upregulated in renal tissues collected from db/db mice, but its specific role in diabetic nephropathy was still unclear. This study aimed to explore the effect of miR-494-3p on renal fibrosis using an in vitro cell model of diabetic nephropathy. METHODS: After human renal tubular epithelial cells (HK-2) were treated with high glucose (HG), the viability and apoptosis of cells were examined by CCK-8 assays and flow cytometry analyses. Additionally, protein levels of fibronectin, collagen I, collagen III, collagen IV, and epithelial-mesenchymal transition (EMT) markers in HG-induced HK-2 cells were quantified by western blotting. MiR-494-3p expression in HK-2 cells was detected by reverse transcription quantitative polymerase chain reaction. The binding relation between miR-494-3p and the messenger RNA suppressor of cytokine signaling 6 (SOCS6) was detected by luciferase reporter assays. RESULTS: HG reduced cell viability and enhanced cell apoptosis in a time- or concentration-dependent manner. Additionally, HG induced collagen accumulation and triggered the EMT process. miR-494-3p was upregulated in HG-treated HK-2 cells. MiR-494-3p inhibition alleviated HG-induced cell dysfunction. Mechanistically, miR-494-3p bound with SOCS6 and negatively regulated SOCS6 expression. Moreover, silencing SOCS6 rescued the suppressive effect of miR-499-5p inhibition on HG-induced cell dysfunction. CONCLUSION: MiR-494-3p aggravates renal fibrosis, EMT process and cell apoptosis by targeting SOCS6, suggesting that the miR-494-3p/SOCS6 axis may become a potential strategy for the treatment of diabetic nephropathy.

2.
Am J Infect Control ; 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34986389

RESUMO

OBJECTIVES: To consider a one-year time window of the COVID-19 crisis to integrate qualitative and quantitative data and provide an in-depth analysis of all COVID-19 publications from geographical, epidemiological and chronological perspectives. METHODS: Publications on COVID-19 from December 1, 2019, to December 31, 2020 without document type limitations were extracted from the Web of Science database. Microsoft Excel 2016, GraphPad Prism 9, VOSviewer 1.6.15 and IBM SPSS 21.0 were used to analyze the global epidemiological publication landscape and its correlations, research hotspots around the world and the top 5 countries in terms of publications. RESULTS: A total of 51,317 documents were analyzed in the present study. The publication trend could be divided into an increasing output stage and an explosive output stage. There were positive correlations between monthly publications, confirmed cases and deaths. Research hotspots from the whole year, from individual quarters, and from the top 5 countries with the most publications were further identified. CONCLUSIONS: The correlation analysis of publications indicated that confirmed cases and deaths were forces driving the scientific output, reflecting the growing trend to some extent. Moreover, the hotspot analysis provided valuable information for scientists, funders, policy and decision-makers to determine what areas should be their focus when faced with public health emergencies in the future.

3.
J Hazard Mater ; 425: 127917, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-34915291

RESUMO

The present study demonstrated that the perchlorate reduction rate in a methane-based membrane biofilm reactor was significantly enhanced from 14.4 to 25.6 mg-Cl/L/d by increasing copper concentration in the feeding medium from 1 to 10 µM, indicating a stimulatory effect of copper on the methane-supported perchlorate reduction process. Batch tests further confirmed that the increased copper concentration enhanced both methane oxidation and perchlorate reduction rates, which was supported by an increasing trend of functional genes (pmoA for methanotrophs and pcrA for specific perchlorate reducers) abundances through quantitative polymerase chain reaction (qPCR). Both 16S rRNA gene sequencing and functional genes (pmoA and pcrA) sequencing jointly revealed that the biofilm supplied with a higher copper concentration exhibited a more diverse microbial community. The methane-supported perchlorate reduction was accomplished through a synergistic association of methanotrophs (Methylocystis, Methylomonas, and Methylocystaceae) and perchlorate reducers (Dechloromonas, Azospira, Magnetospirillum, and Denitratisoma). Acetate may function as the key syntrophic linkage between methanotrophs and perchlorate reducers. It was proposed that the increased copper concentration improved the activity of particulate methane monooxygenase (pMMO) for methane oxidation or promoted the biosynthesis of intracellular carbon storage compounds polyhydroxybutyrate (PHB) in methanotrophs for generating more acetate available for perchlorate reduction.

4.
Biology (Basel) ; 10(12)2021 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-34943216

RESUMO

BACKGROUND: The dysregulation of autophagy and immunological processes has been linked to various pathophysiological conditions, including cancer. Most notably, their particular involvement in hepatocellular carcinoma (HCC) is becoming increasingly evident. This has led to the possibility of developing a prognostic signature based on immuno-autophagy-related (IAR) genes. Given that long non-coding RNAs (lncRNAs) also play a special role in HCC, a combined signature utilizing IAR genes and HCC-associated long noncoding RNAs (as IARlncRNA) may potentially help in the clinical scenario. METHOD: We used Pearson correlation analysis, Kaplan-Meier survival curves, univariate and multivariate Cox regression, and ROC curves to generate and validate a prognostic immuno-autophagy-related long non-coding RNA (IARlncRNA) signature. The Chi-squared test was utilized to investigate the correlation between the obtained signature and the clinical characteristics. CIBERSORT algorithms and the Wilcoxon rank sum test were applied to investigate the correlation between signature and infiltrating immune cells. GO and KEGG analyses were performed to derived signature-dependent pathways. RESULTS: Herein, we build an IAR-lncRNA signature (as first in the literature) and demonstrate its prognostic ability in hepatocellular carcinoma. Primarily, we identified three IARlncRNAs (MIR210HG, AC099850.3 and CYTOR) as unfavorable prognostic determinants. The obtained signature predicted the high-risk HCC group with shorter overall survival, and was further associated with clinical characteristics such as tumor grade (t = 10.918, p = 0.001). Additionally, several infiltrating immune cells showed varied fractions between the low-risk group and the high-risk HCC groups in association with the obtained signature. In addition, pathways analysis described by the signature clearly distinguishes both risk groups in HCC. CONCLUSIONS: The immuno-autophagy-related long non-coding RNA (IARlncRNA) signature we established exhibits a prognostic ability in hepatocellular carcinoma. To our knowledge, this is the first attempt in the literature to combine three determinants (immune, autophagy and LnRNAs), thus requiring molecular validation of this obtained signature in clinical samples.

5.
Signal Transduct Target Ther ; 6(1): 378, 2021 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-34732694

RESUMO

The current COVID-19 pandemic has heavily burdened the global public health system and may keep simmering for years. The frequent emergence of immune escape variants have spurred the search for prophylactic vaccines and therapeutic antibodies that confer broad protection against SARS-CoV-2 variants. Here we show that the bivalency of an affinity maturated fully human single-domain antibody (n3113.1-Fc) exhibits exquisite neutralizing potency against SARS-CoV-2 pseudovirus, and confers effective prophylactic and therapeutic protection against authentic SARS-CoV-2 in the host cell receptor angiotensin-converting enzyme 2 (ACE2) humanized mice. The crystal structure of n3113 in complex with the receptor-binding domain (RBD) of SARS-CoV-2, combined with the cryo-EM structures of n3113 and spike ecto-domain, reveals that n3113 binds to the side surface of up-state RBD with no competition with ACE2. The binding of n3113 to this novel epitope stabilizes spike in up-state conformations but inhibits SARS-CoV-2 S mediated membrane fusion, expanding our recognition of neutralization by antibodies against SARS-CoV-2. Binding assay and pseudovirus neutralization assay show no evasion of recently prevalent SARS-CoV-2 lineages, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) for n3113.1-Fc with Y58L mutation, demonstrating the potential of n3113.1-Fc (Y58L) as a promising candidate for clinical development to treat COVID-19.


Assuntos
Enzima de Conversão de Angiotensina 2/química , Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , COVID-19 , SARS-CoV-2/química , Anticorpos de Cadeia Única/química , Enzima de Conversão de Angiotensina 2/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/uso terapêutico , Cristalografia por Raios X , Epitopos/química , Epitopos/imunologia , Humanos , Camundongos , SARS-CoV-2/imunologia , Anticorpos de Cadeia Única/imunologia , Anticorpos de Cadeia Única/uso terapêutico
6.
Mikrochim Acta ; 188(12): 407, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34735602

RESUMO

A dual-mode DNA sensor was constructed to detect nucleic acid sensitively and selectively. Based on dendritic porous silica nanoparticles (DPSNs) and hybridization chain reaction (HCR) amplification strategy, the fabricated DNA sensor showed good sensitivity with low detection limits down to 2.18 pM and 4.02 pM by fluorescence (excited at 488 nm and emitted at 508 nm) and personal glucose meter (PGM) assays, respectively. This dual-mode detection of DNA offered superior reliability and accuracy and could meet the requirements of different testing environments, including laboratory confirmation and portable detection. Moreover, the impact of nanoparticles morphology on detection performance was also discussed. Due to the center-radial pores, DPSNs had high curvature morphology, which improved the coverage capacity, footprint, and deflection angle of probes. This work fabricated a dual-mode DNA sensor and revealed the relationship between morphology and detection performance, which brought new insights in novel biosensor development.

7.
Int J Biol Markers ; 36(3): 48-54, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34596453

RESUMO

BACKGROUND: This study explored the relevance between rs1695 and susceptibility to the lung cancer in the Chinese Han population. Stratification analysis was conducted on the basis of age, gender, smoking status, tumor-related family history, and pathological type to observe relations between rs1695 and susceptibility to lung cancer in the subgroups. METHODS: A case-control study was performed with 974 lung cancer patients who were pathologically diagnosed and 1005 healthy cases based on physical examination to analyze the association between rs1695 and the risk of lung cancer. RESULTS: The frequencies of the AA, GA, and GG genotypes of rs1695 were 68.4%, 28.7%, and 2.9% in cases and 64.8%, 30.8%, and 4.2% in controls, respectively. After adjustment for age, gender, smoking status, and family history, it appears that the rs1695 G allele decreases the risk of lung cancer (OR = 0.811, 95% CI 0.684-0.961, P = 0.016). Moreover, compared with the AA genotype, the GA + GG genotype decreased lung cancer susceptibility (OR = 0.808, 95% CI 0.663-0.985, P = 0.035) and the GG genotype (OR = 0.591, 95% CI 0.347-0.988, P = 0.048). In a stratified analysis, the risk of lung cancer in the G allele carriers decreased among the males, patients without a tumor-related family history, and patients with lung adenocarcinoma, especially in smokers. CONCLUSION: The polymorphism of locus rs1695 is related to the risk of lung cancer and is expected to be a target for the prediction of lung cancer.

8.
Neurogastroenterol Motil ; : e14255, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34494345

RESUMO

BACKGROUND: Self-efficacy in defecation plays an important role on behavioral therapy for functional constipation (FC). There is an unmet need for valid child self-report measures of task-specific self-efficacy for pediatric FC. Our aim was to cross-culturally validate the Self-Efficacy for Functional Constipation Questionnaire (SEFCQ) and to explore the salient factor(s) of self-efficacy in defecation that correlate with anxiety and constipation symptom severity among Chinese children. METHODS: The SEFCQ was adapted to Chinese version following the Rome Foundation guidelines for the translation of questionnaires. Two hundred and three children with FC were involved in psychometric testing. Confirmatory factor analysis was conducted to determine the structure of the SEFCQ. Construct validity was evaluated by testing the relationship between the SEFCQ and both anxiety and the Patient Assessment of Constipation Symptoms (PAC-SYM). Test-retest reliability, internal consistency, and interfactor correlation were used to evaluate reliability. Hierarchical multiple regression was used to identify salient self-efficacy for FC that correlates with anxiety and constipation symptom severity. KEY RESULTS: Confirmatory factor analysis supports the two-factor structure of the SEFCQ. Adequate test-retest reliability (r = 0.973, p<0.001) and internal consistency (Cronbach's α = 0.871) were obtained. Both self-efficacy factors were significantly associated with anxiety (r = -0.227 to -0.350, p<0.001) and PAC-SYM (r = -0.495 to -0.602, p<0.001), with emotional self-efficacy being the most salient factor for predicting the symptom severity of constipation after controlling for sex, age, quality of parents' marriage, and family history. CONCLUSION AND INFERENCES: The SEFCQ showed satisfactory psychometric properties. Low self-efficacy in defecation correlates with anxiety and may contribute to poor adherence to behavior change, which exacerbates the symptoms of constipation. Further study is needed to apply social cognitive intervention to increase children's self-efficacy in defecation and assess its effect on treatment outcomes.

9.
Asian J Psychiatr ; 65: 102846, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34562753

RESUMO

BACKGROUND: As a global pandemic, coronavirus disease 2019 (COVID-19) has had a profound effect on public mental health. METHODS: Publications related to mental health during the COVID-19 pandemic from December 1, 2019, to November 13, 2020, were extracted from the Web of Science database. Bibliometric indicator analysis was performed using VOSviewer 1.6.15. RESULTS: In total, 1233 documents from 2020 were retrieved, of which 680 were original articles. The United States contributed the largest publication output (285, 23.1%). Huazhong University of Science and Technology published the most articles in this field (35), while Wuhan University received the most citations (1149). The United Kingdom had the strongest collaboration network. Four keyword clusters representing hotspots in this field were identified. CONCLUSIONS: In addition to developed countries, countries seriously affected by the COVID-19 pandemic also made significant contributions to mental health research during the COVID-19 pandemic. This study focused on various aspects, such as mental health during isolation, mental health in healthcare workers, and public mental health issues during the COVID-19 pandemic. In the future, countries should strengthen global cooperation and pay more attention to the mental health of vulnerable groups during pandemics.


Assuntos
COVID-19 , Pandemias , Bibliometria , Humanos , Saúde Mental , SARS-CoV-2 , Estados Unidos
10.
G3 (Bethesda) ; 11(9)2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34544147

RESUMO

Threonyl-tRNA synthetase (ThrRS), one of the aminoacyl-tRNA synthetases (AARSs), plays a crucial role in protein synthesis. However, the AARS functions on rice chloroplast development and growth were not fully appraised. In this study, a thermo-sensitive virescent mutant tsv2, which showed albino phenotype and lethal after the 4-leaf stage at 20°C but recovered to normal when the temperatures rose, was identified and characterized. Map-based cloning and complementation tests showed that TSV2 encoded a chloroplast-located ThrRS protein in rice. The Lys-to-Arg mutation in the anticodon-binding domain hampered chloroplast development under cold stress, while the loss of function of the ThrRS core domain in TSV2 fatally led to seedling death regardless of growing temperatures. In addition, TSV2 had a specific expression in early leaves. Its disruption obviously resulted in the downregulation of certain genes associated with chlorophyll biosynthesis, photosynthesis, and chloroplast development at cold conditions. Our observations revealed that rice nuclear-encoded TSV2 plays an important role in chloroplast development at the early leaf stage under cold stress.


Assuntos
Oryza , Treonina-tRNA Ligase , Cloroplastos/genética , Cloroplastos/metabolismo , Resposta ao Choque Frio , Regulação da Expressão Gênica de Plantas , Mutação , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plântula/genética , Plântula/metabolismo
11.
Front Genet ; 12: 681867, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34276784

RESUMO

Background: Some studies have proven that autophagy and lncRNA play important roles in AML. Several autophagy related lncRNA signatures have been shown to affect the survival of patients in some other cancers. However, the role of autophagy related lncRNA in AML has not been explored yet. Hence, this study aims to find an autophagy related lncRNA signature that can affect survival for AML patients. Method: A Pearson correlation analysis, a Kaplan-Meier survival curve, a univariate cox regression, and a multivariate cox regression were performed to establish an autophagy related lncRNA signature. A univariate cox regression, a multivariate cox regression, a Kaplan-Meier survival curve, and a ROC curve were applied to confirm if the signature is an independent prognosis for AML patients. The relationship between the signature and the clinical features was explored by using a T test. Gene Set Enrichment Analysis (GSEA) was used to investigate the potential tumor related pathways. Results: A four-autophagy related lncRNA (MIR133A1HG, AL359715.1, MIRLET7BHG, and AL356752.1) signature was established. The high risk score based on signature was related to the short survival time of AML patients. The signature was an independent factor for the prognosis for AML patients (HR = 1.684, 95% CI = 1.324-2.142, P < 0.001). The signature was correlated with age, leukocyte numbers, and FAB (M3 or non-M3). The P53, IL6/JAK/STAT3, TNF-α, INF-γ, and IL2/STAT5 pathways might contribute to the differences between the risk groups based on signature in AML. Conclusion: The four autophagy related lncRNAs and their signature might be novel biomarkers for predicting the survival of AML patients. Some biological pathways might be the potential mechanisms of the signature for the survival of AML patients.

12.
Virol Sin ; 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34196914

RESUMO

Similar to that of other enteroviruses, the replication of enterovirus 71 (EV71) occurs on rearranged membranous structures called replication organelles (ROs). Phosphatidylinositol 4-kinase III (PI4KB), which is required by enteroviruses for RO formation, yields phosphatidylinositol-4-phosphate (PI4P) on ROs. PI4P then binds and induces conformational changes in the RNA-dependent RNA polymerase (RdRp) to modulate RdRp activity. Here, we targeted 3D polymerase, the core enzyme of EV71 ROs, and found that the host factor Annexin A2 (ANXA2) can interact with 3D polymerase and promote the replication of EV71. Then, an experiment showed that the annexin domain of ANXA2, which possesses membrane-binding capacity, mediates the interaction of ANXA2 with EV71 3D polymerase. Further research showed that ANXA2 is localized on ROs and interacts with PI4KB. Overexpression of ANXA2 stimulated the formation of PI4P, and the level of PI4P was decreased in ANXA2-knockout cells. Furthermore, ANXA2, PI4KB, and 3D were shown to be localized to the viral RNA replication site, where they form a higher-order protein complex, and the presence of ANXA2 promoted the PI4KB-3D interaction. Altogether, our data provide new insight into the role of ANXA2 in facilitating formation of the EV71 RNA replication complex.

13.
Gynecol Endocrinol ; 37(12): 1072-1078, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34165386

RESUMO

OBJECTIVE: To assess the prevalence of anxiety and depression symptoms of different severity in women with polycystic ovary syndrome (PCOS) and explore the potential contributors related to these symptoms using a meta-analysis. MATERIALS AND METHODS: Databases were systemically searched for cross-sectional studies that evaluated the prevalence of anxiety and depression in women with PCOS published up to September 21 2019. Random effects model or fixed-effect model was used to analyze the data in meta-analysis. The pooled odds ratio (OR) and the pooled standardized mean difference (SMD) were performed to estimate the potential factors related to these symptoms. RESULT: A total of 24 cross-sectional studies were included. All studies assessed depression (2316 women with PCOS). Moreover, 16 studies assessed anxiety (1698 women with PCOS), and 6 studies assessed anxiety with depression (736 women with PCOS). The analysis revealed an increase in pool prevalence of depression (42%, 95%CI: 33-52%) and anxiety (37%, 95%CI: 14-60%) among the participants with PCOS, while the pooled prevalence of depression and concurrent anxiety was 28% (95%CI: 1.7-54.2%). Besides, the pooled prevalence of mild symptoms was higher than other levels (depression: 27.5%, 95%CI: 19-36%; anxiety: 35%, 95%CI: 0.8-70.8%). Obese women with PCOS had higher odds of depression (2.098, 95% CI: 1.411-3.119, I2=0.00%, p > .05). CONCLUSIONS: Our meta-analysis confirmed that women with PCOS had a high prevalence of anxiety and depression of different severity, with mild symptoms being more common. Moreover, obesity may increase the risk of depression symptoms, while potential contributors and mechanisms affecting these symptoms, such as hirsutism, infertility, insulin resistance (IR), and total testosterone in women with PCOS, need to be further investigated.

14.
Int J Biol Macromol ; 184: 92-100, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34116094

RESUMO

Feruloyl esterase is an indispensable biocatalyst in food processing, pesticide and pharmaceutical industries, catalyzing the cleavage of the ester bond cross-linked between the polysaccharide side chain of hemicellulose and ferulic acid in plant cell walls. LP_0796 from Lactobacillus plantarum was identified as a feruloyl esterase that may have potential applications in the food industry, but the lack of the substrate recognition and catalytic mechanisms limits its application. Here, LP_0796 showed the highest activity towards methyl caffeate at pH 6.6 and 40 °C. The crystal structure of LP_0796 was determined at 2.5 Å resolution and featured a catalytic triad Asp195-containing loop facing the opposite direction, thus forming a wider substrate binding pocket. Molecular docking simulation and site-directed mutagenesis studies further demonstrated that in addition to the catalytic triad (Ser94, Asp195, His225), Arg125 and Val128 played essential roles in the function of the active site. Our data also showed that Asp mutation of Ala23 and Ile198 increased the catalytic efficiency to 4- and 5-fold, respectively. Collectively, this work provided a better understanding of the substrate recognition and catalytic mechanisms of LP_0796 and may facilitate the future protein design of this important feruloyl esterase.


Assuntos
Ácidos Cafeicos/metabolismo , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Lactobacillus plantarum/enzimologia , Mutagênese Sítio-Dirigida/métodos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Biocatálise , Hidrolases de Éster Carboxílico/genética , Domínio Catalítico , Cristalografia por Raios X , Indústria Farmacêutica , Manipulação de Alimentos , Temperatura Alta , Concentração de Íons de Hidrogênio , Lactobacillus plantarum/genética , Modelos Moleculares , Simulação de Acoplamento Molecular , Conformação Proteica , Especificidade por Substrato
15.
Microorganisms ; 9(5)2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34069209

RESUMO

The respiratory chain is very important for bacterial survival and pathogenicity, yet the roles of the respiratory chain in P. aeruginosa remain to be fully elucidated. Here, we not only proved experimentally that the operon PA4427-PA4431 of Pseudomonas aeruginosa PAO1 encodes respiratory chain complex III (cytobc1), but also found that it played important roles in virulence and pathogenicity. PA4429-31 deletion reduced the production of the virulence factors, including pyocyanin, rhamnolipids, elastase, and extracellular polysaccharides, and it resulted in a remarkable decrease in pathogenicity, as demonstrated in the cabbage and Drosophila melanogaster infection models. Furthermore, RNA-seq analysis showed that PA4429-31 deletion affected the expression levels of the genes related to quorum-sensing systems and the transport of iron ions, and the iron content was also reduced in the mutant strain. Taken together, we comprehensively illustrated the function of the operon PA4427-31 and its application potential as a treatment target in P. aeruginosa infection.

16.
J Agric Food Chem ; 69(23): 6665-6675, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34074097

RESUMO

Gut bacteria-derived enzymes play important roles in the metabolism of dietary fiber through enabling the hydrolysis of polysaccharides. In this study, we identified and characterized a 29 kDa novel acetyl xylan esterase, BTAxe1, from Bacteroides thetaiotaomicron VPI5482. Then, we solved the structure of BTAxe1 and performed the rational design. Mutants N65S and N65A increased the activities toward short-chain (pNPA, pNPB) to near four-fold, and gained the activities toward longer-chain substrate (pNPO). Molecular docking analysis showed that the mutant N65S had a larger substrate binding pocket than the wild type. Hydrolysis studies using natural substrates showed that either N65S or N65A showed higher activity of that of wild-type, yielding 131.31 and 136.09 mM of acetic acid from xylan. This is the first study on the rational design of gut bacteria-derived Axes with broadened substrate specificity and enhanced activity, which can be referenced by other acetyl esterases or gut-derived enzymes.


Assuntos
Bacteroides thetaiotaomicron , Acetilesterase/genética , Acetilesterase/metabolismo , Bacteroides thetaiotaomicron/genética , Simulação de Acoplamento Molecular , Especificidade por Substrato
17.
J Agric Food Chem ; 69(21): 6064-6072, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-33979121

RESUMO

The human gut microbiota regulates nutritional metabolism, especially by encoding specific ferulic acid esterases (FAEs) to release functional ferulic acid (FA) from dietary fiber. In our previous study, we observed seven upregulated FAE genes during in vitro fecal slurry fermentation using wheat bran. Here, a 29 kDa FAE (AsFAE) from Alistipes shahii of Bacteroides was characterized and identified as the type-A FAE. The X-ray structure of AsFAE has been determined, revealing a unique α-helical domain comprising five α-helices, which was first characterized in FAEs from the gut microbiota. Further molecular docking analysis and biochemical studies revealed that Tyr100, Thr122, Tyr219, and Ile220 are essential for substrate binding and catalytic efficiency. Additionally, Glu129 and Lys130 in the cap domain shaped the substrate-binding pocket and affected the substrate preference. This is the first report on A. shahii FAE, providing a theoretical basis for the dietary metabolism in the human gut.


Assuntos
Hidrolases de Éster Carboxílico , Bacteroidetes , Hidrolases de Éster Carboxílico/metabolismo , Humanos , Simulação de Acoplamento Molecular , Conformação Proteica em alfa-Hélice , Especificidade por Substrato
18.
Water Res ; 200: 117215, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-34020333

RESUMO

Short chain gaseous alkanes (SCGAs) mainly consist of methane (CH4), ethane (C2H6), propane (C3H8) and butane (C4H10). The first three SCGAs have been shown to remove perchlorate (ClO4-) and selenate (SeO42-), yet it is unknown whether C4H10 is available to reduce these contaminants. This study demonstrated that C4H10 fed biofilms were capable of reducing ClO4- and SeO42- to chloride (Cl-) and elemental selenium (Se0), respectively, by employing two independent membrane biofilms reactors (MBfRs). Batch tests showed that C4H10 and oxygen fed biofilms had much higher ClO4- and SeO42- reduction rates and enhanced expression levels of bmoX and pcrA than that without C4H10 or O2. Polyhydroxyalkanoates (PHA) accumulated in the biofilms when C4H10 was supplied, and they decomposed for driving ClO4- and SeO42- reduction when C4H10 was absent. Moreover, we revisited the literature and found that a cross-feeding pathway seems to be universal in microaerobic SCGA-driven perchlorate and selenate reduction processes. In the ClO4--reducing MBfRs, Mycobacterium primarily conducts C2H6 and C3H8 oxidation in synergy with Dechloromonas who performs perchlorate reduction, while both Mycobacterium and Rhodococcus carried out C4H10 oxidation with perchlorate-respiring Azospira as the partner. In the SeO42--reducing MBfRs, Mycobacterium oxidized C2H6 solely or oxidized C3H8 jointly with Rhodococcus, while Burkholderiaceae likely acted as the selenate-reducing bacterium. When C4H10 was supplied as the electron donor, both Mycobacterium and Rhodococcus conducted C4H10 oxidation in synergy with unknow selenate-reducing bacterium. Collectively, we confirm that from CH4 to C4H10, all SCGAs could be utilized as electron donors for bio-reduction process. These findings offer insights into SCGA-driven bio-reduction processes, and are helpful in establishing SCGA-based technologies for groundwater remediation.


Assuntos
Reatores Biológicos , Percloratos , Alcanos , Biofilmes , Gases , Oxirredução , Ácido Selênico
19.
Bioresour Technol ; 332: 124967, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33845316

RESUMO

Producing ferulic acid (FA) from the natural substrate with feruloyl esterase is promising in industries, screening and engineering new enzymes with high efficiency to increase the FA yield is of great concern. Here, the feruloyl esterase of Lactobacillus acidophilus (FAELac) was heterologous expressed and the FAELac with different oligomerization states was separated. Interestingly, the activity of dimer was 37-fold higher than high-polymer. To further enhance the efficiency of FAELac, eight mutants were generated based on the simulated structure, of which Q198A, Q134T enhanced the catalytic efficiency by 5.4- and 4.3-fold in comparison with the wild type. Moreover, higher yields of FA (2.21, 6.60, and 1.67 mg/g substrate, respectively) were released by the mutants from de-starched wheat bran, insoluble wheat arabinoxylan, and steam-exploded corn stover. These results indicated that improving the purification process, engineering new FAELac and substrates bias studies hold great potential for increasing FA production yield.


Assuntos
Hidrolases de Éster Carboxílico , Lactobacillus acidophilus , Hidrolases de Éster Carboxílico/genética , Hidrolases de Éster Carboxílico/metabolismo , Ácidos Cumáricos , Lactobacillus acidophilus/metabolismo , Especificidade por Substrato
20.
Water Res ; 198: 117150, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33910142

RESUMO

Although methane (CH4) has been proven to be able to serve as an electron donor for bio-reducing various oxidized contaminants (e.g., selenate (SeO42-)), little is known regarding the roles of oxygen in methane-based reduction processes. Here, a methane-based membrane biofilm reactor (MBfR) was established for evaluating the effects of oxygen supply rates on selenate reduction performance and microbial communities. The oxygen supply rate played a dual role (stimulatory or suppressive effect) in selenate reduction rates, depending on the presence or absence of dissolved oxygen (DO). Specifically, selenate reduction rate was substantially enhanced when an appropriate oxygen rate (e.g., 12 to 184 mg/L.d in this study) was supplied but with negligible DO. The highest selenate reduction rate (up to 34 mg-Se/L.d) was obtained under an oxygen supply rate of 184 mg/L.d. In contrast, excessive oxygen supply rate (626 mg/L.d) would significantly suppress selenate reduction rate under DO level of 3 mg/L. Accordingly, though the high oxygen supply rate (626 mg/L.d) would promote the expression of pmoA (5.9 × 109 copies g-1), the expression level of narG (a recognized gene to mediate selenate reduction) would be significantly downregulated (6.1 × 109 copies g-1), thus suppressing selenate reduction. In contrast, the expression of narG gene significantly increased to 2.8 × 1010 copies g-1, and the expression of pmoA gene could still maintain at 1.1 × 109 copies g-1 under an oxygen supply rate of 184 mg/L.d. High-throughput sequencing targeting 16S rRNA gene, pmoA, and narG collectively suggested Methylocystis acts as the major aerobic methanotroph, in synergy with Arthrobacter and Variovorax which likely jointly reduce selenate to selenite (SeO32-), and further to elemental selenium (Se0). Methylocystis was predominant in the biofilm regardless of variations of oxygen supply rates, while Arthrobacter and Variovorax were sensitive to oxygen fluctuation. These findings provide insights into the effects of oxygen on methane-dependent selenate reduction and suggest that it is feasible to achieve a higher selenate removal by regulating oxygen supply rates.


Assuntos
Metano , Oxigênio , Biofilmes , Reatores Biológicos , Oxirredução , RNA Ribossômico 16S/genética , Ácido Selênico
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