Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 145
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
BMC Genomics ; 25(1): 203, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38389079

RESUMO

BACKGROUND: Firmiana danxiaensis is a critically endangered and ecologically important tree currently only found in four locations in Danxia or Karst habitats in northern Guangdong Province, China. The specialized habitat preference makes it an ideal model species for study of adaptive evolution. Meanwhile, the phylogenetic relationships of F. danxiaensis in four locations under two landforms are unclear. Therefore, we sequenced its complete chloroplast (cp.) genomes and conducted comprehensive interspecific and intrageneric plastome studies. RESULTS: The F. danxiaensis plastomes in four locations showed a typical quadripartite and circular structure that ranged from 160,832 to 161,206 bp in size, with 112 unique genes encoded. Comparative genomics showed that the plastomes of F. danxiaensis were relatively conserved with high similarity of genome organization, gene number, GC content and SSRs. While the genomes revealed higher biased codon preferences in Karst habitat than those in Danxia habitats. Eighteen and 11 divergent hotpots were identified at interspecific and intrageneric levels for species identification and further phylogenetic studies. Seven genes (clpP, accD, ccsA, ndhH, rpl20, rpoC2, and rps4) were under positive selection and may be related to adaptation. Phylogenetic analysis revealed that F. danxiaensis is sister to F. major and F. simplex. However, the interspecific relationships are not consistent with the habitat types. CONCLUSIONS: The characteristics and interspecific relationship of F. danxiaensis plastomes provide new insights into further integration of geographical factors, environmental factors, and genetic variations on the genomic study of F. danxiaensis. Together, our study will contribute to the study of species identification, population genetics, and conservation biology of F. danxiaensis.


Assuntos
Genoma de Cloroplastos , Filogenia , Genoma de Cloroplastos/genética , Genômica , Sequência de Bases , Genética Populacional
2.
BMC Cancer ; 24(1): 913, 2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39080593

RESUMO

BACKGROUND: In China, the national cervical cancer screening protocol involves initial testing for high-risk human papillomavirus (hrHPV), followed by cytology for hrHPV-positive cases. This study evaluates the effectiveness of PAX1 methylation (PAX1m) analysis in identifying precancerous or cancerous lesions in cervical samples from Chinese women positive for non-16/18 hrHPV strains. METHODS: Between February 2022 and March 2023, 281 cervical samples from non-16/18 hrHPV-positive women underwent cytological examination and PAX1m analysis. The study assessed the statistical relationship between PAX1m levels and the presence of cervical lesions, comparing the diagnostic performance of PAX1m to conventional cytology. RESULTS: A significant association was found between PAX1 methylation levels and the risk of CIN2 + and CIN3 + lesions, with 47 instances of CIN2 + detected. Odds ratios (ORs) for moderate and high PAX1m levels were 8.86 (95% CI: 2.24-42.17) and 166.32 (95% CI: 47.09-784.97), respectively. The area under the ROC curve for PAX1m in identifying CIN2 + lesions was 0.948 (95% CI: 0.895-0.99). PAX1m demonstrated similar sensitivity and negative predictive value (NPV) to cytology but reduced the colposcopy referral rate from 47.7% with cytology alone to 25.6% with PAX1m, showing superior specificity and positive predictive value across age groups. CONCLUSIONS: PAX1 methylation is a strong indicator of CIN2 + and CIN3 + risk, offering diagnostic performance comparable to cytology with the added benefit of reduced unnecessary colposcopy referrals. These findings support the use of PAX1m analysis as a reliable tool for triaging non-16/18 hrHPV-positive women in outpatient settings.


Assuntos
Metilação de DNA , Detecção Precoce de Câncer , Fatores de Transcrição Box Pareados , Infecções por Papillomavirus , Triagem , Displasia do Colo do Útero , Neoplasias do Colo do Útero , Humanos , Feminino , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/virologia , Neoplasias do Colo do Útero/genética , Pessoa de Meia-Idade , Detecção Precoce de Câncer/métodos , Adulto , Fatores de Transcrição Box Pareados/genética , Infecções por Papillomavirus/virologia , Infecções por Papillomavirus/diagnóstico , Infecções por Papillomavirus/complicações , Infecções por Papillomavirus/genética , Triagem/métodos , Displasia do Colo do Útero/diagnóstico , Displasia do Colo do Útero/virologia , Displasia do Colo do Útero/genética , China/epidemiologia , Idoso , Curva ROC , Biomarcadores Tumorais/genética , Esfregaço Vaginal
3.
BMC Gastroenterol ; 24(1): 240, 2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39075402

RESUMO

PURPOSE: This study aimed to investigate clinical diagnostic values of mSEPT9 combined with NLR, PLR and LMR in CRC. METHODS: 329 subjects composed of 120 CRC patients, 105 polyps patients and 104 healthy participants were prospectively recruited. Clinicopathologic features were collected and analyzed. Plasma samples were collected for mSEPT9, NLR, PLR and LMR test. The sensitivity, specificity and AUC of each biomarker separately or in combination were estimated by the ROC curve. RESULTS: The levels of NLR, PLR and the PDR of mSEPT9 in CRC patients were significantly higher than those in non-CRC subjects, while LMR was the opposite. The PDR of mSEPT9 in CRC patients was significantly correlated with age, tumor size, tumor stage and M stage. ROC curve analysis demonstrated moderate diagnostic values of mSEPT9, NLR, PLR and LMR in CRC patients with AUC of 0.78 (Se = 0.68, and Sp = 0.89), 0.78 (Se = 0.68, and Sp = 0.83), 0.80 (Se = 0.68, and Sp = 0.81), and 0.77 (Se = 0.72, and Sp = 0.73), respectively. Moreover, combination of these four biomarkers dramatically enhanced the diagnostic accuracy of CRC (AUC = 0.92, Se = 0.90, and Sp = 0.87), especially for CRC patients with large tumors (AUC = 0.95) or distal metastasis (AUC = 0.95). CONCLUSION: mSEPT9, NLR, PLR and LMR showed the potential to be reliable biomarkers for the diagnosis of CRC. And the combined application of these biomarkers further improved the diagnostic accuracy of CRC significantly.


Assuntos
Biomarcadores Tumorais , Neoplasias Colorretais , Septinas , Humanos , Septinas/sangue , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/sangue , Masculino , Feminino , Pessoa de Meia-Idade , Biomarcadores Tumorais/sangue , Sensibilidade e Especificidade , Curva ROC , Idoso , Estudos Prospectivos , Contagem de Plaquetas , Metilação de DNA , Adulto , Estudos de Casos e Controles , Neutrófilos , Estadiamento de Neoplasias , Plaquetas
4.
J Obstet Gynaecol Res ; 50(6): 1051-1055, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38423535

RESUMO

Primary leiomyosarcoma of the fallopian tube (PLFT) is an extremely rare gynecological malignancy that has only been described in case reports. Fertility-sparing treatment for PLFT has not been reported previously. A 24-year-old nulligravida woman was diagnosed with stage IC1 PLFT in the right fallopian tube after experiencing right lower quadrant pain for 2 weeks. She underwent laparoscopic right salpingectomy to preserve fertility followed by adjuvant chemotherapy with gemcitabine/docetaxel. She subsequently became pregnant spontaneously, delivering a term baby 27 months after treatment. This appears to be the only report of the use of fertility-preserving treatment for PLFT. The success of the treatment provides valuable information on the preservation of fertility in young women with PLFT.


Assuntos
Neoplasias das Tubas Uterinas , Preservação da Fertilidade , Leiomiossarcoma , Humanos , Feminino , Leiomiossarcoma/cirurgia , Leiomiossarcoma/tratamento farmacológico , Gravidez , Preservação da Fertilidade/métodos , Neoplasias das Tubas Uterinas/tratamento farmacológico , Neoplasias das Tubas Uterinas/cirurgia , Adulto Jovem , Salpingectomia , Adulto , Docetaxel/uso terapêutico , Docetaxel/administração & dosagem
5.
J Cell Mol Med ; 28(5): e17895, 2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37525480

RESUMO

Immune checkpoint inhibitors (ICIs) therapy have revolutionized advanced lung cancer care. Interestingly, the host responses for patients received ICIs therapy are distinguishing from those with cytotoxic drugs, showing potential initial transient worsening of disease burden, pseudoprogression and delayed time to treatment response. Thus, a new imaging criterion to evaluate the response for immunotherapy should be developed. ICIs treatment is associated with unique adverse events, including potential life-threatening immune checkpoint inhibitor-related pneumonitis (ICI-pneumonitis) if treated patients are not managed promptly. Currently, the diagnosis and clinical management of ICI-pneumonitis remain challenging. As the clinical manifestation is often nonspecific, computed tomography (CT) scan and X-ray films play important roles in diagnosis and triage. This article reviews the complications of immunotherapy in lung cancer and illustrates various radiologic patterns of ICI-pneumonitis. Additionally, it is tried to differentiate ICI-pneumonitis from other pulmonary pathologies common to lung cancer such as radiation pneumonitis, bacterial pneumonia and coronavirus disease of 2019 (COVID-19) infection in recent months. Maybe it is challenging to distinguish radiologically but clinical presentation may help.

6.
Brief Bioinform ; 22(3)2021 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32392583

RESUMO

N6-methyladenosine (m6A) is the most abundant posttranscriptional modification in mammalian mRNA molecules and has a crucial function in the regulation of many fundamental biological processes. The m6A modification is a dynamic and reversible process regulated by a series of writers, erasers and readers (WERs). Different WERs might have different functions, and even the same WER might function differently in different conditions, which are mostly due to different downstream genes being targeted by the WERs. Therefore, identification of the targets of WERs is particularly important for elucidating this dynamic modification. However, there is still no public repository to host the known targets of WERs. Therefore, we developed the m6A WER target gene database (m6A2Target) to provide a comprehensive resource of the targets of m6A WERs. M6A2Target provides a user-friendly interface to present WER targets in two different modules: 'Validated Targets', referred to as WER targets identified from low-throughput studies, and 'Potential Targets', including WER targets analyzed from high-throughput studies. Compared to other existing m6A-associated databases, m6A2Target is the first specific resource for m6A WER target genes. M6A2Target is freely accessible at http://m6a2target.canceromics.org.


Assuntos
Adenosina/análogos & derivados , Bases de Dados Genéticas , Neoplasias/genética , Adenosina/metabolismo , Humanos , Mutação , Reprodutibilidade dos Testes
7.
Metab Eng ; 78: 72-83, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37201565

RESUMO

Microbial production of valuable bioproducts is a promising route towards green and sustainable manufacturing. The oleaginous yeast, Rhodosporidium toruloides, has emerged as an attractive host for the production of biofuels and bioproducts from lignocellulosic hydrolysates. 3-hydroxypropionic acid (3HP) is an attractive platform molecule that can be used to produce a wide range of commodity chemicals. This study focuses on establishing and optimizing the production of 3HP in R. toruloides. As R. toruloides naturally has a high metabolic flux towards malonyl-CoA, we exploited this pathway to produce 3HP. Upon finding the yeast capable of catabolizing 3HP, we then implemented functional genomics and metabolomic analysis to identify the catabolic pathways. Deletion of a putative malonate semialdehyde dehydrogenase gene encoding an oxidative 3HP pathway was found to significantly reduce 3HP degradation. We further explored monocarboxylate transporters to promote 3HP transport and identified a novel 3HP transporter in Aspergillus pseudoterreus by RNA-seq and proteomics. Combining these engineering efforts with media optimization in a fed-batch fermentation resulted in 45.4 g/L 3HP production. This represents one of the highest 3HP titers reported in yeast from lignocellulosic feedstocks. This work establishes R. toruloides as a host for 3HP production from lignocellulosic hydrolysate at high titers, and paves the way for further strain and process optimization towards enabling industrial production of 3HP in the future.


Assuntos
Lignina , Engenharia Metabólica , Engenharia Metabólica/métodos , Lignina/metabolismo
8.
Metab Eng ; 80: 163-172, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37778408

RESUMO

Aconitic acid is an unsaturated tricarboxylic acid that is attractive for its potential use in manufacturing biodegradable and biocompatible polymers, plasticizers, and surfactants. Previously Aspergillus pseudoterreus was engineered as a platform to produce aconitic acid by deleting the cadA (cis-aconitic acid decarboxylase) gene in the itaconic acid biosynthetic pathway. In this study, the aconitic acid transporter gene (aexA) was identified using comparative global discovery proteomics analysis between the wild-type and cadA deletion strains. The protein AexA belongs to the Major Facilitator Superfamily (MFS). Deletion of aexA almost abolished aconitic acid secretion, while its overexpression led to a significant increase in aconitic acid production. Transportation of aconitic acid across the plasma membrane is a key limiting step in its production. In vitro, proteoliposome transport assay further validated AexA's function and substrate specificity. This research provides new approaches to efficiently pinpoint and characterize exporters of fungal organic acids and accelerate metabolic engineering to improve secretion capability and lower the cost of bioproduction.


Assuntos
Ácido Aconítico , Aspergillus , Ácido Aconítico/metabolismo , Aspergillus/genética , Aspergillus/metabolismo , Proteínas de Membrana Transportadoras/genética , Engenharia Metabólica , Succinatos/metabolismo
9.
Cancer Cell Int ; 23(1): 278, 2023 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-37980521

RESUMO

BACKGROUND: RPLP2, an integral part of ribosomal stalk, plays an important role in the tumorigenesis of various cancers. However, its specific effect on HCC remains elusive. METHODS: TCGA, GTEx, HCCDB, HPA, UALCAN, MethSurv, TISIDB, K-M plotter, FerrDb, RNAactDrug, STRING, Cytoscape and R studio were conducted for bioinformatics analysis. RPLP2 expression level in HCC was verified by IHC and western blot. IHC was used to demonstrate the immune cell infiltration. Functional experiments including CCK8, transwell and colony formation assays, and nude mice xenograft model were performed for in vitro and in vivo validation. Western blot, IHC, CCK8 assay and detection of GSH and lipid ROS were adopted to determine the effect of RPLP2 on the ferroptosis of HCC cells. RESULTS: Here, we demonstrate that elevated level of RPLP2 is strongly associated with advanced clinicopathologic features, and predicts poor prognosis of HCC patients. Additionally, DNA methylation level of RPLP2 decreases in HCC, and significantly correlates with patients outcome. Moreover, high RPLP2 expression level is linked closely to the unfavorable immune infiltration. Most importantly, RPLP2 positively associates with ferroptosis suppressor GPX4, and inhibition of RPLP2 could lead to the acceleration of ferroptosis to suppress tumor progression of HCC. Last, drug sensitivity analysis predicts many drugs that potentially target RPLP2. CONCLUSION: Together, our study reveals previous unrecognized role of RPLP2 in HCC, and provides new regulatory mechanism of ferroptosis, indicating RPLP2 may be a novel therapeutic target for HCC.

10.
Mol Ther ; 30(3): 1089-1103, 2022 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-34995801

RESUMO

N6-methyladenosine (m6A) is the most prevalent RNA modification, and the effect of its dysregulation on esophageal squamous cell carcinoma (ESCC) development remains unclear. Here, by performing transcriptome-wide m6A sequencing in 16 ESCC tissue samples, we identified the key roles of m6A in TNFRSF1A (also known as TNFR1)-mediated MAPK and NF-κB activation in ESCC. Mechanistically, a functional protein involved in m6A methylation, ATXN2, is identified that augments the translation of TNFRSF1A by binding to m6A-modified TNFRSF1A mRNA. Upregulation of the TNFRSF1A protein level, a vital upstream switch for TNFRSF1A-mediated signaling events, activates the NF-κB and MAPK pathways and thus promotes ESCC development. Furthermore, TNFRSF1A m6A modifications and protein levels are upregulated in ESCC, and high levels of TNFRSF1A m6A and protein are correlated with poor ESCC patient survival. These results collectively indicate that the m6A-TNFRSF1A axis is critical for ESCC development and thus may serve as a potential druggable target.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Ataxina-2/genética , Ataxina-2/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , NF-kappa B/metabolismo , RNA Mensageiro/genética , Receptores Tipo I de Fatores de Necrose Tumoral/genética
11.
Hell J Nucl Med ; 26(3): 224-225, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38085839

RESUMO

Pericardial inflammatory myofibroblastic tumor (IMT) is very rare. Herein, we report fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) findings of pericardial IMT in a 57-year-old woman. On conventional image, it presented as a pericardial mass with heterogeneous delay enhancement. On 18F-FDG PET/CT image, this lesion had mild 18F-FDG uptake with a maximum standardized uptake value (SUVmax) of 1.84. The postoperative pathology supported a diagnosis of IMT. Our case hints us that IMT should be regarded as a differential diagnosis when we meet a solitary pericardial mass with 18F-FDG uptake.


Assuntos
Neoplasias , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Feminino , Humanos , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Fluordesoxiglucose F18 , Diagnóstico Diferencial
12.
J Am Chem Soc ; 144(50): 23230-23238, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36508583

RESUMO

Direct functionalization of carbonyl ß C-H bonds without using directing groups has not been a trivial task, and it is even more challenging to realize the corresponding atom-economical transformations with common alkenes or alkynes as the coupling partner. Here, we describe the development of an iridium-catalyzed intramolecular direct ß-alkenylation of ketones with regular alkynes. The reaction is redox neutral, avoids strong acids or bases, and tolerates various functional groups. The combined experimental and computational mechanistic studies reveal a hydride-transfer pathway, involving ketone α,ß-desaturation, iridium-hydride-mediated alkyne insertion, conjugate addition, and α-protonation.


Assuntos
Alcinos , Irídio , Alcinos/química , Cetonas/química , Catálise , Alcenos/química
13.
J Am Chem Soc ; 144(46): 21347-21355, 2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36367320

RESUMO

The first copper-catalyzed enantioselective [4 + 1] annulation of yne-allylic esters with 1,3-dicarbonyl compounds was realized through an elegant remote stereocontrol strategy. The very remote ε regioselective nucleophilic substitution was developed by employing a novel chiral copper-vinylvinylidene species from the new C4 synthon yne-allylic esters. Thus, greatly diverse spirocycles were obtained with ample scope and excellent levels of chemo-, regio-, and enantioselectivities. Moreover, detailed mechanistic studies suggest an yne-allylic substitution and Conia-ene cascade pathway on the remote stereochemical induction progress.


Assuntos
Cobre , Ésteres , Cobre/química , Estereoisomerismo , Catálise , Estrutura Molecular
14.
J Am Chem Soc ; 144(34): 15779-15785, 2022 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-35976107

RESUMO

Distinct regio- and enantioselectivity control in copper-catalyzed vinylogous and bisvinylogous propargylic substitution has been accomplished by using a novel chiral N,N,P ligand. The developed method provides an efficient and selective approach to an array of highly enantioenriched alkynyl unsaturated carbonyl compounds. Salient features include excellent functional group tolerance and broad substrate scope. The synthetic utility of the developed method is further demonstrated by a gram-scale synthesis and by application to a range of transformations including enantioselective synthesis of unique challenging compounds.


Assuntos
Cobre , Catálise , Cobre/química , Ligantes , Estrutura Molecular , Estereoisomerismo
15.
J Cell Mol Med ; 25(1): 120-131, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33205602

RESUMO

Osteoarthritis (OA) is an ageing-related disease characterized by articular cartilage degradation and joint inflammation. circRNA has been known to involve in the regulation of multiple inflammatory diseases including OA. However, the mechanism underlying how circRNA regulates OA remains to be elucidated. Here, we report circANKRD36 prevents OA chondrocyte apoptosis and inflammation by targeting miR-599, which specifically degrades Casz1. We performed circRNA sequencing in normal and OA tissues and found the expression of circANKRD36 is decreased in OA tissues. circANKRD36 is also reduced in IL-1ß-treated human chondrocytes. FACS analysis and Western blot showed that the knockdown of circANKRD36 promotes the apoptosis and inflammation of chondrocytes in IL-1ß stress. We then found miR-599 to be the target of circANKRD36 and correlate well with circANKRD36 both in vitro and in vivo. By database analysis and luciferase assay, Casz1 was found to be the direct target of miR-599. Casz1 helps to prevent apoptosis and inflammation of chondrocytes in response to IL-1ß. In conclusion, our results proved circANKRD36 sponge miR-599 to up-regulate the expression of Casz1 and thus prevent apoptosis and inflammation in OA.


Assuntos
Apoptose/genética , Condrócitos/patologia , Proteínas de Ligação a DNA/genética , Inflamação/genética , MicroRNAs/metabolismo , Osteoartrite/genética , RNA Circular/metabolismo , Fatores de Transcrição/genética , Idoso , Idoso de 80 Anos ou mais , Sequência de Bases , Condrócitos/metabolismo , Proteínas de Ligação a DNA/metabolismo , Humanos , Interleucina-1beta/metabolismo , MicroRNAs/genética , Pessoa de Meia-Idade , RNA Circular/genética , Fatores de Transcrição/metabolismo
16.
J Am Chem Soc ; 143(19): 7253-7260, 2021 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-33961421

RESUMO

Herein, we report a modular and convergent strategy for the assembly of atropisomeric o-terphenyls with 1,2-diaxes via palladium/chiral norbornene cooperative catalysis and axial-to-axial diastereoinduction. Readily available aryl iodides, 2,6-substituted aryl bromides, and potassium aryl trifluoroborates are used as the building blocks, laying the foundation for diversity-oriented synthesis of these scaffolds (46 examples). Other features include the unique axial-to-axial diastereoinduction mode, construction of two axes in a single operation, and step economy. DFT calculations are performed to rationalize the axial-to-axial diastereoinduction process. Synthetic utilities of this method in preparation of atropisomeric oligophenyls, chiral catalysts, and ligands are demonstrated.

17.
Genomics ; 112(5): 3448-3454, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32569729

RESUMO

Recent studies suggest that a significant proportion of cancers undergo neutral tumor evolution. We applied neutral evolution model in HNSCC patients from The Cancer Genome Atlas (TCGA). To ensure the accuracy of classification results, a sample with the purity of tumor <0.7 was excluded. A tumor sample was considered to evolve neutrally if R2 ≥ 0.98. We found that about 16% of HNSCC patients undergo neutral tumor evolution. We showed that neutral evolution HNSCC patients have better prognosis and higher activities of immune response pathways, and the numbers of co-occurring mutation events and significantly positive selection mutations are significantly less than non-neutral evolution HNSCC patients. In conclusion, we described a comprehensive clinical and genomic characteristics of neutral tumor evolution in Head and Neck Squamous Cell Carcinoma (HNSCC), and provided evidence that the evolution history of HNSCC has both clinical and biological implications.


Assuntos
Neoplasias de Cabeça e Pescoço/genética , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Genômica , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/imunologia , Neoplasias de Cabeça e Pescoço/mortalidade , Humanos , Mutação , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico por imagem , Carcinoma de Células Escamosas de Cabeça e Pescoço/imunologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/mortalidade
18.
Angew Chem Int Ed Engl ; 60(5): 2355-2363, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33089963

RESUMO

The regio- and enantioselective (3+3) cycloaddition of nitrones with 2-indolylmethanols was accomplished by the cooperative catalysis of hexafluoroisopropanol (HFIP) and chiral phosphoric acid (CPA). Using this approach, a series of indole-fused six-membered heterocycles were synthesized in high yields (up to 98 %), with excellent enantioselectivities (up to 96 % ee) and exclusive regiospecificity. This approach enabled not only the first organocatalytic asymmetric (3+3) cycloaddition of nitrones but also the first C3-nucleophilic asymmetric (3+3) cycloaddition of 2-indolylmethanols. More importantly, theoretical calculations elucidated the role of the cocatalyst HFIP in helping CPA control the reactivity and enantioselectivity of the reaction, demonstrating a new mode of cooperative catalysis.

19.
J Am Chem Soc ; 142(37): 15686-15696, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32845127

RESUMO

Atroposelective synthesis of axially chiral molecules has attracted substantial attention from chemists because of the importance of such molecules. However, catalytic asymmetric synthesis of axially chiral styrenes or vinyl arenes is underdeveloped and challenging due to the low rotational barrier and weak configurational stability of such molecules. Therefore, the development of powerful strategies for the catalytic atroposelective synthesis of axially chiral styrenes or vinyl arenes is of great importance. In this work, we have accomplished the first atroposelective access to oxindole-based axially chiral styrenes by the strategy of catalytic kinetic resolution, and this strategy offered two kinds of oxindole-based axially chiral styrene derivatives in good diastereoselectivities (up to 94:6 dr) and excellent enantioselectivities (up to 98% ee) with high selectivity factors (S up to 106). This strategy not only provides easy access to oxindole-based axially chiral styrenes but also offers a robust method for synthesizing bisamide derivatives bearing both axial and central chirality. More importantly, this strategy has added a new class of members to the atropisomeric family, especially to the family of axially chiral styrenes.

20.
Mol Phylogenet Evol ; 143: 106673, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31707137

RESUMO

The early-branching Cladrastis clade of papilionoid legumes (Leguminosae, Papilionoideae) has an intriguing amphi-Pacific disjunct distribution in eastern Asia and temperate-tropical Americas. Here we used nuclear and three plastid regions to reconstruct the phylogenetic relationships and divergence times in the Cladrastis clade, as well as the evolution of morphological characters that might have been key in its biogeographic history. The ancestral character state estimation revealed that the most recent common ancestor of the Cladrastis clade was deciduous trees possessing compressed, winged fruits. The Cladrastis clade was inferred to have originated in the mid-latitude thermophilic forests of North America in the early Eocene, followed by the split between ancestors of wing-fruited Platyosprion and the non-wing-fruited group, and later the divergence of Cladrastis s.s. from the non-wing-fruited group in middle Eocene. Platyosprion and Cladrastis s.s. display an "out-of-North-America" biogeographic pattern and might have migrated to Asia via the Bering land bridge (BLB) or the North Atlantic land bridges (NALB) during middle to late Eocene. Our results, coupled with the relatively well documented fossil record for the clade, suggest that Platyosprion experienced an extinction event in North America caused by climatic cooling around the Eocene-Oligocene transition, which drove a major vegetation shift in western North America, in turn serving as a barrier for the vicariance of Pickeringia and Styphnolobium. The evolution of shrubby habit and sclerophyllous leaves in the former might be adaption to the chaparral vegetation in southwestern North America; the latter gained the trait of moniliform, succulent fruit. Styphnolobium further dispersed southward to tropical North America in the Oligocene, and eastward to Asia through BLB during middle Miocene. Subsequent sundering of BLB facilitated the vicariance of St. affine and St. japonicum.


Assuntos
Fabaceae/classificação , Fósseis , Ásia , Fabaceae/genética , América do Norte , Filogenia , Filogeografia , Plastídeos/classificação , RNA Ribossômico 5,8S/classificação , RNA Ribossômico 5,8S/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA