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1.
Research (Wash D C) ; 2019: 2602414, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31549053

RESUMO

4-Hydroxyphenylpyruvate dioxygenase (HPPD) is a promising target for drug and pesticide discovery. The unknown binding mode of substrate is still a big challenge for the understanding of enzymatic reaction mechanism and novel HPPD inhibitor design. Herein, we determined the first crystal structure of Arabidopsis thaliana HPPD (AtHPPD) in complex with its natural substrate (HPPA) at a resolution of 2.80 Å. Then, combination of hybrid quantum mechanics/molecular mechanics (QM/MM) calculations confirmed that HPPA takes keto rather than enol form inside the HPPD active pocket. Subsequent site-directed mutagenesis and kinetic analysis further showed that residues (Phe424, Asn423, Glu394, Gln307, Asn282, and Ser267) played important roles in substrate binding and catalytic cycle. Structural comparison between HPPA-AtHPPD and holo-AtHPPD revealed that Gln293 underwent a remarkable rotation upon the HPPA binding and formed H-bond network of Ser267-Asn282-Gln307-Gln293, resulting in the transformation of HPPD from an inactive state to active state. Finally, taking the conformation change of Gln293 as a target, we proposed a new strategy of blocking the transformation of HPPD from inactive state to active state to design a novel inhibitor with K i value of 24.10 nM towards AtHPPD. The inhibitor has entered into industry development as the first selective herbicide used for the weed control in sorghum field. The crystal structure of AtHPPD in complex with the inhibitor (2.40 Å) confirmed the rationality of the design strategy. We believe that the present work provides a new starting point for the understanding of enzymatic reaction mechanism and the design of next generation HPPD inhibitors.

2.
World J Gastroenterol ; 25(34): 5197-5209, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31558867

RESUMO

BACKGROUND: Colorectal high-grade neuroendocrine neoplasms (HGNENs) are rare and constitute less than 1% of all colorectal malignancies. Based on their morphological differentiation and proliferation identity, these neoplasms present heterogeneous clinicopathologic features. Opinions regarding treatment strategies for and improvement of the clinical outcomes of these patients remain controversial. AIM: To delineate the clinicopathologic features of and explore the prognostic factors for this rare malignancy. METHODS: This observational study reviewed the data of 72 consecutive patients with colorectal HGNENs from three Chinese hospitals between 2000 and 2019. The clinicopathologic characteristics and follow-up data were carefully collected from their medical records, outpatient reexaminations, and telephone interviews. A survival analysis was conducted to evaluate their outcomes and to identify the prognostic factors for this disease. RESULTS: According to the latest recommendations for the classification and nomenclature of colorectal HGNENs, 61 (84.7%) patients in our cohort had poorly differentiated neoplasms, which were categorized as high-grade neuroendocrine carcinomas (HGNECs), and the remaining 11 (15.3%) patients had well differentiated neoplasms, which were categorized as high-grade neuroendocrine tumors (HGNETs). Most of the neoplasms (63.9%) were located at the rectum. More than half of the patients (51.4%) presented with distant metastasis at the date of diagnosis. All patients were followed for a median duration of 15.5 mo. In the entire cohort, the median survival time was 31 mo, and the 3-year and 5-year survival rates were 44.3% and 36.3%, respectively. Both the univariate and multivariate analyses demonstrated that increasing age, HGNEC type, and distant metastasis were risk factors for poor clinical outcomes. CONCLUSION: Colorectal HGNENs are rare and aggressive malignancies with poor clinical outcomes. However, patients with younger age, good morphological differentiation, and without metastatic disease can have a relatively favorable prognosis.


Assuntos
Carcinoma Neuroendócrino/epidemiologia , Neoplasias Colorretais/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Neuroendócrino/patologia , China/epidemiologia , Neoplasias Colorretais/patologia , Feminino , Seguimentos , Humanos , Incidência , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Prognóstico , Estudos Prospectivos , Taxa de Sobrevida , Fatores de Tempo , Adulto Jovem
3.
Molecules ; 24(16)2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31408943

RESUMO

A multi-residue method for the determination of 107 pesticide residues in wolfberry has been developed and validated. Similar pretreatment approaches were compared, and the linearity, matrix effect, analysis limits, precision, stability and accuracy were validated, which verifies the satisfactory performance of this new method. The LODs and LOQs were in the range of 0.14-1.91 µg/kg and 0.46-6.37 µg/kg, respectively. The recovery of analytes at three fortification levels (10 µg/kg, 50 µg/kg, 100 µg/kg) ranged from 63.3-123.0%, 72.0-118.6% and 67.0-118.3%, respectively, with relative standard deviations (RSDs) below 15.0%. The proposed method was applied to the analysis of fifty wolfberry samples collected from supermarkets, pharmacies and farmers' markets in different cities of Shandong Province. One hundred percent of the samples analyzed included at least one pesticide, and a total of 26 pesticide residues was detected in fifty samples, which mainly were insecticides and bactericide. Several pesticides with higher detection rates were 96% for acetamiprid, 82% for imidacloprid, 54% for thiophanate-methyl, 50% for blasticidin-S, 42% for carbendazim, 42% for tebuconazole and 36% for difenoconazole in wolfberry samples. This study proved the adaptability of the developed method to the detection of multiple pesticide residues in wolfberry and provided basis for the research on the risks to wolfberry health.


Assuntos
Extração Líquido-Líquido/métodos , Lycium/química , Resíduos de Praguicidas/isolamento & purificação , Benzimidazóis/isolamento & purificação , Carbamatos/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Neonicotinoides/isolamento & purificação , Nitrocompostos/isolamento & purificação , Nucleosídeos/isolamento & purificação , Resíduos de Praguicidas/classificação , Espectrometria de Massas em Tandem/métodos , Tiofanato/isolamento & purificação , Triazóis/isolamento & purificação
4.
World J Gastrointest Oncol ; 11(7): 538-550, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31367273

RESUMO

BACKGROUND: Intraoperative intraperitoneal chemotherapy is an emerging treatment modality for locally advanced rectal neoplasms. However, its impacts on postoperative complications remain unknown. Anastomotic leakage (AL) is one of the most common and serious complications associated with the anterior resection of rectal tumors. Therefore, we designed this study to determine the effects of intraoperative intraperitoneal chemotherapy on AL. AIM: To investigate whether intraoperative intraperitoneal chemotherapy increases the incidence of AL after the anterior resection of rectal neoplasms. METHODS: This retrospective cohort study collected information from 477 consecutive patients who underwent an anterior resection of rectal carcinoma using the double stapling technique at our institution from September 2016 to September 2017. Based on the administration of intraoperative intraperitoneal chemotherapy or not, the patients were divided into a chemotherapy group (171 cases with intraperitoneal implantation of chemotherapy agents during the operation) or a control group (306 cases without intraoperative intraperitoneal chemotherapy). Clinicopathologic features, intraoperative treatment, and postoperative complications were recorded and analyzed to determine the effects of intraoperative intraperitoneal chemotherapy on the incidence of AL. The clinical outcomes of the two groups were also compared through survival analysis. RESULTS: The univariate analysis showed a significantly higher incidence of AL in the patients who received intraoperative intraperitoneal chemotherapy, with 13 (7.6%) cases in the chemotherapy group and 5 (1.6%) cases in the control group (P = 0.001). As for the severity of AL, the AL patients who underwent intraoperative intraperitoneal chemotherapy tended to be more severe cases, and 12 (92.3%) out of 13 AL patients in the chemotherapy group and 2 (40.0%) out of 5 AL patients in the control group required a secondary operation (P = 0.044). A multivariate analysis was subsequently performed to adjust for the confounding factors and also showed that intraoperative intraperitoneal chemotherapy increased the incidence of AL (odds ratio = 5.386; 95%CI: 1.808-16.042; P = 0.002). However, the survival analysis demonstrated that intraoperative intraperitoneal chemotherapy could also improve the disease-free survival rates for patients with locally advanced rectal cancer. CONCLUSION: Intraoperative intraperitoneal chemotherapy can improve the prognosis of patients with locally advanced rectal carcinoma, but it also increases the risk of AL following the anterior resection of rectal neoplasms.

5.
Genes (Basel) ; 8(9)2017 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-28837073

RESUMO

Bacterial nuclease RecJ, which exists in almost all bacterial species, specifically degrades single-stranded (ss) DNA in the 5' to 3' direction. Some archaeal phyla, except Crenarchaea, also encode RecJ homologs. Compared with bacterial RecJ, archaeal RecJ exhibits a largely different amino acid sequence and domain organization. Archaeal RecJs from Thermococcus kodakarensis and Pyrococcus furiosus show 5'→3' exonuclease activity on ssDNA. Interestingly, more than one RecJ exists in some Euryarchaeota classes, such as Methanomicrobia, Methanococci, Methanomicrobia, Methanobacteria, and Archaeoglobi. Here we report the biochemical characterization of two RecJs from Methanocaldococcus jannaschii, the long RecJ1 (MJ0977) and short RecJ2 (MJ0831) to understand their enzymatic properties. RecJ1 is a 5'→3' exonuclease with a preference to ssDNA; however, RecJ2 is a 3'→5' exonuclease with a preference to ssRNA. The 5' terminal phosphate promotes RecJ1 activity, but the 3' terminal phosphate inhibits RecJ2 nuclease. Go-Ichi-Ni-San (GINS) complex does not interact with two RecJs and does not promote their nuclease activities. Finally, we discuss the diversity, function, and molecular evolution of RecJ in archaeal taxonomy. Our analyses provide insight into the function and evolution of conserved archaeal RecJ/eukaryotic Cdc45 protein.

6.
Nucleic Acids Res ; 45(21): 12551-12564, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30053256

RESUMO

RecJ nucleases specifically degrade single-stranded (ss) DNA in the 5' to 3' direction. Archaeal RecJ is different from bacterial RecJ in sequence, domain organization, and substrate specificity. The RecJ from archaea Pyrococcus furiosus (PfuRecJ) also hydrolyzes RNA strands in the 3' to 5' direction. Like eukaryotic Cdc45 protein, archaeal RecJ forms a complex with MCM helicase and GINS. Here, we report the crystal structures of PfuRecJ and the complex of PfuRecJ and two CMPs. PfuRecJ bind one or two divalent metal ions in its crystal structure. A channel consisting of several positively charged residues is identified in the complex structure, and might be responsible for binding substrate ssDNA and/or releasing single nucleotide products. The deletion of the complex interaction domain (CID) increases the values of kcat/Km of 5' exonuclease activity on ssDNA and 3' exonuclease activity on ssRNA by 5- and 4-fold, respectively, indicating that the CID functions as a regulator of enzymatic activity. The DHH domain of PfuRecJ interacts with the C-terminal beta-sheet domain of the GINS51 subunit in the tetrameric GINS complex. The relationship of archaeal and bacterial RecJs, as well as eukaryotic Cdc45, is discussed based on biochemical and structural results.


Assuntos
Proteínas de Bactérias/química , Exodesoxirribonucleases/química , Pyrococcus furiosus/enzimologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Proteínas de Bactérias/fisiologia , Cátions , Proteínas de Ciclo Celular , Sequência Conservada , Cristalografia por Raios X , Reparo do DNA , Replicação do DNA , DNA Bacteriano/metabolismo , DNA de Cadeia Simples/metabolismo , Proteínas de Ligação a DNA/metabolismo , Evolução Molecular , Exodesoxirribonucleases/fisiologia , Modelos Moleculares , Complexos Multiproteicos/metabolismo , Fosfodiesterase I/metabolismo , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
7.
Org Biomol Chem ; 14(3): 1024-30, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26633006

RESUMO

An organocatalytic dearomative [3 + 2]-annulation of N-alkyl-3-alkylindoles with quinone monoketals is developed. The reaction provides a mild and straightforward way to various benzofuro[2,3-b]indolines of potential biological and pharmaceutical interest in moderate to good yields. Moreover, when 3-phenylindole, a problematic substrate in previous relevant studies, was used as the substrate under the otherwise same reaction conditions, a novel 1,2-shift of the phenyl group occurred followed by aromatization to provide 2,3-diaryl indoles useful for cancer therapy studies in moderate yields.


Assuntos
Ácidos/química , Benzoquinonas/química , Indóis/química , Indóis/síntese química , Catálise , Ciclização , Modelos Moleculares , Estrutura Molecular
8.
Bioresour Technol ; 135: 254-61, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23305897

RESUMO

Sulfuric acid treated corn fiber hydrolysate (SACFH) inhibited cell growth and the production of butanol (4.7±0.2 g/L) by Clostridium beijerinckii IB4 in P2 medium. Optimal medium components were determined using fractional factorial design. NH4HCO3, FeSO4·7H2O and CaCO3 were demonstrated to be significant components in the production of butanol. The Box-Behnken design and a corresponding quadratic model were used to predict medium components (NH4HCO3 1.96 g/L, FeSO4·7H2O 0.26 g/L and CaCO3 3.15 g/L) and butanol yield (9.5 g/L). The confirmation experiment, under the predicted optimal conditions, yielded a butanol level of 9.5±0.1g/L. This study indicates that the Box-Behnken design is an effective approach for screening the optimal medium components required for the production of butanol. It also demonstrates that SACFH, which has high levels of inhibitors such as furan and phenolic compounds, may be used as a renewable carbon source in the production of biofuels.


Assuntos
Butanóis/metabolismo , Clostridium beijerinckii/genética , Mutação/genética , Ácidos Sulfúricos/farmacologia , Zea mays/metabolismo , Análise de Variância , Carbono/farmacologia , Clostridium beijerinckii/efeitos dos fármacos , Meios de Cultura/farmacologia , Hidrólise/efeitos dos fármacos , Reprodutibilidade dos Testes , Zea mays/efeitos dos fármacos
9.
Antiviral Res ; 89(1): 98-108, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21108969

RESUMO

To investigate the anti-herpesvirus mechanism of pentagalloylglucose (PGG), we compared the proteomic changes between herpes simplex virus type 1 (HSV-1) infected MRC-5 cells with or without PGG-treatment, and between non-infected MRC-5 cells with or without PGG-treatment by 2-DE and MS-based analysis. Differentially expressed cellular proteins were mainly involved with actin cytoskeleton regulation. Significantly, PGG can down-regulate cofilin1, a key regulator of actin cytoskeleton dynamics. PGG can inhibit HSV-1-induced rearrangements of actin cytoskeleton which is important for infectivity. Furthermore, cofilin1 knockdown by siRNA also inhibited the HSV-1-induced actin-skeleton rearrangements. Both PGG-treatment and cofilin1 knockdown can reduce HSV-1 DNA, mRNA, protein synthesis and virus yields. Altogether, the results suggested that down-regulating cofilin1 plays a role in PGG inhibiting HSV-1 infection. PGG may be a promising anti-herpesvirus agent for drug development.


Assuntos
Cofilina 1/antagonistas & inibidores , Herpesvirus Humano 1/fisiologia , Taninos Hidrolisáveis/metabolismo , Internalização do Vírus/efeitos dos fármacos , Animais , Linhagem Celular , Cofilina 1/biossíntese , Cofilina 1/genética , Regulação para Baixo , Técnicas de Silenciamento de Genes , Humanos , RNA Interferente Pequeno/metabolismo
10.
Anal Sci ; 26(10): 1033-7, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20953044

RESUMO

Amniotic fluid-derived stem cells (AFSCs) are becoming an important source of cells for regenerative medicine given with apparent advantages of accessibility, renewal capacity and multipotentiality. In this study, the mechanical properties of human amniotic fluid-derived stem cells (hAFSCs), such as the average Young's modulus, were determined by atomic force microscopy (3.97 ± 0.53 kPa for hAFSCs vs. 1.52 ± 0.63 kPa for fully differentiated osteoblasts). These differences in cell elasticity result primarily from differential actin cytoskeleton organization in these two cell types. Furthermore, ultrastructures, nanostructural details on the surface of cell, were visualized by atomic force microscopy (AFM). It was clearly shown that surface of osteoblasts were covered by mineralized particles, and the histogram of particles size showed that most of the particles on the surface of osteoblasts distributed from 200 to 400 nm in diameter, while the diameter of hAFSCs particles ranged from 100 to 200 nm. In contrast, there were some dips on the surface of hAFSCs, and particles were smaller than that of osteoblasts. Additionally, as osteogenic differentiation of hAFSCs progressed, more and more stress fibers were replaced by a thinner actin network which is characteristic of mature osteoblasts. These results can improve our understanding of the mechanical properties of hAFSCs during osteogenic differentiation. AFM can be used as a powerful tool for detecting ultrastructures and mechanical properties.


Assuntos
Diferenciação Celular , Microscopia de Força Atômica , Osteoblastos/citologia , Osteogênese , Células-Tronco/citologia , Citoesqueleto de Actina/ultraestrutura , Líquido Amniótico/citologia , Células Cultivadas , Elasticidade , Humanos , Nanoestruturas , Osteoblastos/ultraestrutura , Células-Tronco/metabolismo , Fatores de Tempo
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