Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 113
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Cell ; 186(13): 2865-2879.e20, 2023 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-37301196

RESUMO

Retroelements are the widespread jumping elements considered as major drivers for genome evolution, which can also be repurposed as gene-editing tools. Here, we determine the cryo-EM structures of eukaryotic R2 retrotransposon with ribosomal DNA target and regulatory RNAs. Combined with biochemical and sequencing analysis, we reveal two essential DNA regions, Drr and Dcr, required for recognition and cleavage. The association of 3' regulatory RNA with R2 protein accelerates the first-strand cleavage, blocks the second-strand cleavage, and initiates the reverse transcription starting from the 3'-tail. Removing 3' regulatory RNA by reverse transcription allows the association of 5' regulatory RNA and initiates the second-strand cleavage. Taken together, our work explains the DNA recognition and RNA supervised sequential retrotransposition mechanisms by R2 machinery, providing insights into the retrotransposon and application reprogramming.


Assuntos
RNA , Retroelementos , RNA/metabolismo , Clivagem do DNA , DNA Polimerase Dirigida por RNA/metabolismo , Transcrição Reversa
2.
Cell ; 170(6): 1224-1233.e15, 2017 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-28844692

RESUMO

CRISPR-Cas9 proteins function within bacterial immune systems to target and destroy invasive DNA and have been harnessed as a robust technology for genome editing. Small bacteriophage-encoded anti-CRISPR proteins (Acrs) can inactivate Cas9, providing an efficient off switch for Cas9-based applications. Here, we show that two Acrs, AcrIIC1 and AcrIIC3, inhibit Cas9 by distinct strategies. AcrIIC1 is a broad-spectrum Cas9 inhibitor that prevents DNA cutting by multiple divergent Cas9 orthologs through direct binding to the conserved HNH catalytic domain of Cas9. A crystal structure of an AcrIIC1-Cas9 HNH domain complex shows how AcrIIC1 traps Cas9 in a DNA-bound but catalytically inactive state. By contrast, AcrIIC3 blocks activity of a single Cas9 ortholog and induces Cas9 dimerization while preventing binding to the target DNA. These two orthogonal mechanisms allow for separate control of Cas9 target binding and cleavage and suggest applications to allow DNA binding while preventing DNA cutting by Cas9.


Assuntos
Sistemas CRISPR-Cas , Endonucleases/antagonistas & inibidores , Proteínas Virais/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bacteriófagos/genética , Bacteriófagos/metabolismo , Endonucleases/química , Endonucleases/genética , Endonucleases/metabolismo , Evolução Molecular , Células HEK293 , Humanos , Domínios Proteicos , Alinhamento de Sequência
3.
Nature ; 630(8016): 484-492, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38811729

RESUMO

The CRISPR system is an adaptive immune system found in prokaryotes that defends host cells against the invasion of foreign DNA1. As part of the ongoing struggle between phages and the bacterial immune system, the CRISPR system has evolved into various types, each with distinct functionalities2. Type II Cas9 is the most extensively studied of these systems and has diverse subtypes. It remains uncertain whether members of this family can evolve additional mechanisms to counter viral invasions3,4. Here we identify 2,062 complete Cas9 loci, predict the structures of their associated proteins and reveal three structural growth trajectories for type II-C Cas9. We found that novel associated genes (NAGs) tended to be present within the loci of larger II-C Cas9s. Further investigation revealed that CbCas9 from Chryseobacterium species contains a novel ß-REC2 domain, and forms a heterotetrameric complex with an NAG-encoded CRISPR-Cas-system-promoting (pro-CRISPR) protein of II-C Cas9 (PcrIIC1). The CbCas9-PcrIIC1 complex exhibits enhanced DNA binding and cleavage activity, broader compatibility for protospacer adjacent motif sequences, increased tolerance for mismatches and improved anti-phage immunity, compared with stand-alone CbCas9. Overall, our work sheds light on the diversity and 'growth evolutionary' trajectories of II-C Cas9 proteins at the structural level, and identifies many NAGs-such as PcrIIC1, which serves as a pro-CRISPR factor to enhance CRISPR-mediated immunity.


Assuntos
Bactérias , Bacteriófagos , Proteína 9 Associada à CRISPR , Sistemas CRISPR-Cas , Bactérias/virologia , Bactérias/genética , Bactérias/imunologia , Bacteriófagos/genética , Bacteriófagos/imunologia , Chryseobacterium/genética , Chryseobacterium/imunologia , Chryseobacterium/virologia , Proteína 9 Associada à CRISPR/química , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Sistemas CRISPR-Cas/imunologia , Clivagem do DNA , Loci Gênicos/genética , Modelos Moleculares , Domínios Proteicos
4.
Mol Cell ; 82(6): 1199-1209.e6, 2022 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-35219382

RESUMO

A compact protein with a size of <1,000 amino acids, the CRISPR-associated protein CasX is a fundamentally distinct RNA-guided nuclease when compared to Cas9 and Cas12a. Although it can induce RNA-guided genome editing in mammalian cells, the activity of CasX is less robust than that of the widely used S. pyogenes Cas9. Here, we show that structural features of two CasX homologs and their guide RNAs affect the R-loop complex assembly and DNA cleavage activity. Cryo-EM-based structural engineering of either the CasX protein or the guide RNA produced two new CasX genome editors (DpbCasX-R3-v2 and PlmCasX-R1-v2) with significantly improved DNA manipulation efficacy. These results advance both the mechanistic understanding of CasX and its application as a genome-editing tool.


Assuntos
Edição de Genes , RNA Guia de Cinetoplastídeos , Animais , Sistemas CRISPR-Cas/genética , Endonucleases/genética , Endonucleases/metabolismo , Edição de Genes/métodos , Mamíferos/metabolismo , RNA/genética , RNA Guia de Cinetoplastídeos/genética , RNA Guia de Cinetoplastídeos/metabolismo
5.
Mol Cell ; 73(3): 601-610.e5, 2019 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-30595438

RESUMO

CRISPR-Cas immune systems utilize RNA-guided nucleases to protect bacteria from bacteriophage infection. Bacteriophages have in turn evolved inhibitory "anti-CRISPR" (Acr) proteins, including six inhibitors (AcrIIA1-AcrIIA6) that can block DNA cutting and genome editing by type II-A CRISPR-Cas9 enzymes. We show here that AcrIIA2 and its more potent homolog, AcrIIA2b, prevent Cas9 binding to DNA by occluding protein residues required for DNA binding. Cryo-EM-determined structures of AcrIIA2 or AcrIIA2b bound to S. pyogenes Cas9 reveal a mode of competitive inhibition of DNA binding that is distinct from other known Acrs. Differences in the temperature dependence of Cas9 inhibition by AcrIIA2 and AcrIIA2b arise from differences in both inhibitor structure and the local inhibitor-binding environment on Cas9. These findings expand the natural toolbox for regulating CRISPR-Cas9 genome editing temporally, spatially, and conditionally.


Assuntos
Proteína 9 Associada à CRISPR/metabolismo , Sistemas CRISPR-Cas , DNA/metabolismo , Edição de Genes/métodos , Fagos de Pseudomonas/metabolismo , Pseudomonas aeruginosa/enzimologia , RNA Guia de Cinetoplastídeos/metabolismo , Temperatura , Proteínas Virais/metabolismo , Ligação Competitiva , Proteína 9 Associada à CRISPR/antagonistas & inibidores , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/ultraestrutura , Microscopia Crioeletrônica , DNA/genética , DNA/ultraestrutura , Escherichia coli/enzimologia , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Modelos Moleculares , Conformação de Ácido Nucleico , Ligação Proteica , Conformação Proteica , Fagos de Pseudomonas/genética , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/virologia , RNA Guia de Cinetoplastídeos/genética , RNA Guia de Cinetoplastídeos/ultraestrutura , Relação Estrutura-Atividade , Proteínas Virais/genética , Proteínas Virais/ultraestrutura
6.
Nature ; 568(7752): E8-E10, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30944483

RESUMO

In this Article, owing to issues with the first 30 nucleotides of the sgRNA, which run in the opposite direction, corrections have been made to the Protein Data Bank (PDB) accessions in the 'Data availability' section, and this also affects Figs. 3, 4, Extended Data Fig. 6, Supplementary Table 1 and Supplementary Video 1. The original Article has been corrected online. See the accompanying Amendment for further details.

7.
Nature ; 566(7743): 218-223, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30718774

RESUMO

The RNA-guided CRISPR-associated (Cas) proteins Cas9 and Cas12a provide adaptive immunity against invading nucleic acids, and function as powerful tools for genome editing in a wide range of organisms. Here we reveal the underlying mechanisms of a third, fundamentally distinct RNA-guided genome-editing platform named CRISPR-CasX, which uses unique structures for programmable double-stranded DNA binding and cleavage. Biochemical and in vivo data demonstrate that CasX is active for Escherichia coli and human genome modification. Eight cryo-electron microscopy structures of CasX in different states of assembly with its guide RNA and double-stranded DNA substrates reveal an extensive RNA scaffold and a domain required for DNA unwinding. These data demonstrate how CasX activity arose through convergent evolution to establish an enzyme family that is functionally separate from both Cas9 and Cas12a.


Assuntos
Proteínas Associadas a CRISPR/classificação , Proteínas Associadas a CRISPR/ultraestrutura , Sistemas CRISPR-Cas/genética , Edição de Genes , Proteínas Associadas a CRISPR/química , Proteínas Associadas a CRISPR/metabolismo , Microscopia Crioeletrônica , DNA/química , DNA/metabolismo , DNA/ultraestrutura , Clivagem do DNA , Escherichia coli/genética , Evolução Molecular , Inativação Gênica , Genoma Bacteriano/genética , Genoma Humano/genética , Humanos , Modelos Moleculares , Conformação de Ácido Nucleico , Domínios Proteicos , RNA Guia de Cinetoplastídeos/metabolismo
8.
Appl Environ Microbiol ; 90(4): e0235523, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38535171

RESUMO

Halophyte-based remediation emerges as a novel strategy for ameliorating saline soils, offering a sustainable alternative to conventional leaching methods. While bioremediation is recognized for its ability to energize soil fertility and structure, the complex interplays among plant traits, soil functions, and soil microbial diversity remain greatly unknown. Here, we conducted a 5-year field experiment involving the continuous cultivation of the annual halophyte Suaeda salsa in saline soils to explore soil microbial diversity and their relationships with plant traits and soil functions. Our findings demonstrate that a decline in soil salinity corresponded with increases in the biomass and seed yield of S. salsa, which sustained a consistent seed oil content of approximately 22% across various salinity levels. Significantly, prolonged cultivation of halophytes substantially augmented soil microbial diversity, particularly from the third year of cultivation. Moreover, we identified positive associations between soil multifunctionality, seed yield, and taxonomic richness within a pivotal microbial network module. Soils enriched with taxa from this module showed enhanced multifunctionality and greater seed yields, correlating with the presence of functional genes implicated in nitrogen fixation and nitrification. Genomic analysis suggests that these taxa have elevated gene copy numbers of crucial functional genes related to nutrient cycling. Overall, our study emphasizes that the continuous cultivation of S. salsa enhances soil microbial diversity and recovers soil multifunctionality, expanding the understanding of plant-soil-microbe feedback in bioremediation.IMPORTANCEThe restoration of saline soils utilizing euhalophytes offers a viable alternative to conventional irrigation techniques for salt abatement and soil quality enhancement. The ongoing cultivation of the annual Suaeda salsa and its associated plant traits, soil microbial diversity, and functionalities are, however, largely underexplored. Our investigation sheds light on these dynamics, revealing that cultivation of S. salsa sustains robust plant productivity while fostering soil microbial diversity and multifunctionality. Notably, the links between enhanced soil multifunctionality, increased seed yield, and network-dependent taxa were found, emphasizing the importance of key microbial taxa linked with functional genes vital to nitrogen fixation and nitrification. These findings introduce a novel understanding of the role of soil microbes in bioremediation and advance our knowledge of the ecological processes that are vital for the rehabilitation of saline environments.


Assuntos
Chenopodiaceae , Solo , Solo/química , Solução Salina , Cloreto de Sódio , Nitrificação , Plantas Tolerantes a Sal
9.
Nucleic Acids Res ; 50(18): 10526-10543, 2022 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-36134711

RESUMO

Transforming growth factor ß (TGF-ß) superfamily proteins are potent regulators of cellular development and differentiation. Nodal/Activin/TGF-ß and BMP ligands are both present in the intra- and extracellular milieu during early development, and cross-talk between these two branches of developmental signaling is currently the subject of intense research focus. Here, we show that the Nodal induced lncRNA-Smad7 regulates cell fate determination via repression of BMP signaling in mouse embryonic stem cells (mESCs). Depletion of lncRNA-Smad7 dramatically impairs cardiomyocyte differentiation in mESCs. Moreover, lncRNA-Smad7 represses Bmp2 expression through binding with the Bmp2 promoter region via (CA)12-repeats that forms an R-loop. Importantly, Bmp2 knockdown rescues defects in cardiomyocyte differentiation induced by lncRNA-Smad7 knockdown. Hence, lncRNA-Smad7 antagonizes BMP signaling in mESCs, and similarly regulates cell fate determination between osteocyte and myocyte formation in C2C12 mouse myoblasts. Moreover, lncRNA-Smad7 associates with hnRNPK in mESCs and hnRNPK binds at the Bmp2 promoter, potentially contributing to Bmp2 expression repression. The antagonistic effects between Nodal/TGF-ß and BMP signaling via lncRNA-Smad7 described in this work provides a framework for understanding cell fate determination in early development.


Assuntos
RNA Longo não Codificante , Proteína Smad7/metabolismo , Ativinas/metabolismo , Ativinas/farmacologia , Animais , Diferenciação Celular , Ligantes , Camundongos , RNA Longo não Codificante/metabolismo , Proteína Smad7/genética , Proteína Smad7/farmacologia , Fator de Crescimento Transformador beta/metabolismo
10.
Ann Surg Oncol ; 30(5): 2942-2953, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36352297

RESUMO

BACKGROUND: An accurate recurrence risk assessment system and surveillance strategy for hepatoid adenocarcinoma of the stomach (HAS) remain poorly defined. This study aimed to develop a nomogram to predict postoperative recurrence of HAS and guide individually tailored surveillance strategies. METHODS: The study enrolled all patients with primary HAS who had undergone curative-intent resection at 14 institutions from 2004 to 2019. Clinicopathologic variables with statistical significance in the multivariate Cox regression were incorporated into a nomogram to build a recurrence predictive model. RESULTS: The nomogram of recurrence-free survival (RFS) based on independent prognostic factors, including age, preoperative carcinoembryonic antigen, number of examined lymph nodes, perineural invasion, and lymph node ratio, achieved a C-index of 0.723 (95% confidence interval [CI], 0.674-0.772) in the whole cohort, which was significantly higher than those of the eighth American Joint Committed on Cancer (AJCC) staging system (C-index, 0.629; 95% CI, 0.573-0.685; P < 0.001). The nomogram accurately stratified patients into low-, middle-, and high-risk groups of postoperative recurrence. The postoperative recurrence risk rates for patients in the middle- and high-risk groups were respectively 3 and 10 times higher than for the low-risk group. The patients in the middle- and high-risk groups showed more recurrence and metastasis, particularly multiple site metastasis, within 36 months after the operation than those in the low-risk group (low, 2.2%; middle, 8.6%; high, 24.0%; P = 0.003). CONCLUSIONS: The nomogram achieved good prediction of postoperative recurrence for the patients with HAS after radical resection. For the middle- and high-risk patients, more active surveillance and targeted examination methods should be adopted within 36 months after the operation, particularly for liver and multiple metastases.


Assuntos
Adenocarcinoma , Neoplasias Gástricas , Humanos , Nomogramas , Prognóstico , Adenocarcinoma/cirurgia , Adenocarcinoma/patologia , Estadiamento de Neoplasias , Estudos Retrospectivos , Neoplasias Gástricas/patologia , Recidiva Local de Neoplasia/patologia
11.
J Nanobiotechnology ; 21(1): 226, 2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37461031

RESUMO

Medial arterial calcification (MAC), a systemic vascular disease different from atherosclerosis, is associated with an increased incidence of cardiovascular events. Several studies have demonstrated that ambient temperature is one of the most important factors affecting cardiovascular events. However, there has been limited research on the effect of different ambient temperatures on MAC. In the present study, we showed that cold temperature exposure (CT) in mice slowed down the formation of vitamin D (VD)-induced vascular calcification compared with room temperature exposure (RT). To investigate the mechanism involved, we isolated plasma-derived exosomes from mice subjected to CT or RT for 30 days (CT-Exo or RT-Exo, respectively). Compared with RT-Exo, CT-Exo remarkably alleviated the calcification/senescence formation of vascular smooth muscle cells (VSMCs) and promoted autophagy by activating the phosphorylation of AMP-activated protein kinase (p-AMPK) and inhibiting phosphorylation of mammalian target of rapamycin (p-mTOR). At the same time, CT-Exo promoted autophagy in ß-glycerophosphate (ß-GP)-induced VSMCs. The number of autophagosomes and the expression of autophagy-related proteins ATG5 and LC3B increased, while the expression of p62 decreased. Based on a microRNA chip microarray assay and real-time polymerase chain reaction, miR-320a-3p was highly enriched in CT-Exo as well as thoracic aortic vessels in CT mice. miR-320a-3p downregulation in CT-Exo using AntagomiR-320a-3p inhibited autophagy and blunted its anti-calcification protective effect on VSMCs. Moreover, we identified that programmed cell death 4 (PDCD4) is a target of miR-320a-3p, and silencing PDCD4 increased autophagy and decreased calcification in VSMCs. Treatment with CT-Exo alleviated the formation of MAC in VD-treated mice, while these effects were partially reversed by GW4869. Furthermore, the anti-arterial calcification protective effects of CT-Exo were largely abolished by AntagomiR-320a-3p in VD-induced mice. In summary, we have highlighted that prolonged cold may be a good way to reduce the incidence of MAC. Specifically, miR-320a-3p from CT-Exo could protect against the initiation and progression of MAC via the AMPK/mTOR autophagy pathway.


Assuntos
Aterosclerose , MicroRNAs , Camundongos , Animais , Proteínas Quinases Ativadas por AMP/metabolismo , Antagomirs , Serina-Treonina Quinases TOR , Autofagia , MicroRNAs/metabolismo , Mamíferos/genética , Mamíferos/metabolismo
12.
Bull Entomol Res ; 113(3): 412-418, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36866720

RESUMO

One of the most common harmful mites in edible fungi is Histiostoma feroniarum Dufour (Acaridida: Histiostomatidae), a fungivorous astigmatid mite that feeds on hyphae and fruiting bodies, thereby transmitting pathogens. This study examined the effects of seven constant temperatures and 10 types of mushrooms on the growth and development of H. feroniarum, as well as its host preference. Developmental time for the total immature stages was significantly affected by the type of mushroom species, ranging from 4.3 ± 0.4 days (reared on Pleurotus eryngii var. tuoliensis Mou at 28°C) to 17.1 ± 2.3 days (reared on Auricularia polytricha Sacc. at 19°C). The temperature was a major factor in the formation of facultative heteromorphic deutonymphs (hypopi). The mite entered the hypopus stage when the temperature dropped to 16°C or rose above 31°C. The growth and development of this mite were significantly influenced by the type of species and variety of mushrooms. Moreover, the fungivorous astigmatid mite preferred to feed on the 'Wuxiang No. 1' strain of Lentinula edodes (Berk.) Pegler and the 'Gaowenxiu' strain of P. pulmonarius (Fr.) Quél., with a shorter development period compared with that of feeding on other strains. These results therefore quantify the effect of host type and temperature on fungivorous astigmatid mite growth and development rates, and provide a reference for applying mushroom cultivar resistance to biological pest control.


Assuntos
Agaricales , Ácaros , Pleurotus , Animais , Temperatura
13.
Chin Med Sci J ; 38(3): 178-190, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37622313

RESUMO

Objective To explore the potential biological functions and prognostic prediction values of non-apoptotic regulated cell death genes (NARCDs) in lung adenocarcinoma.Methods Transcriptome data of lung adenocarcinoma were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases. We identified differentially expressed NARCDs between lung adenocarcinoma tissues and normal tissues with R software. NARCDs signature was constructed with univariate Cox regression analysis and the least absolute shrinkage and selection operator Cox regression. The prognostic predictive capacity of NARCDs signature was assessed by Kaplan-Meier survival curve, receiver operating characteristic curve, and univariate and multivariate Cox regression analyses. Functional enrichment of NARCDs signature was analyzed with gene set variation analysis, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes. In addition, differences in tumor mutational burden, tumor microenvironment, tumor immune dysfunction and exclusion score, and chemotherapeutic drug sensitivity were analyzed between the high and low NARCDs score groups. Finally, a protein-protein interaction network of NARCDs and immune-related genes was constructed by STRING and Cytoscape software. Results We identified 34 differentially expressed NARCDs associated with the prognosis, of which 16 genes (ATIC, AURKA, CA9, ITGB4, DDIT4, CDK5R1, CAV1, RRM2, GAPDH, SRXN1, NLRC4, GLS2, ADRB2, CX3CL1, GDF15, and ADRA1A) were selected to construct a NARCDs signature. NARCDs signature was identified as an independent prognostic factor (P < 0.001). Functional analysis showed that there were significant differences in mismatch repair, p53 signaling pathway, and cell cycle between the high NARCDs score group and low NARCDs score group (all P < 0.05). The NARCDs low score group had lower tumor mutational burden, higher immune score, higher tumor immune dysfunction and exclusion score, and lower drug sensitivity (all P < 0.05). In addition, the 10 hub genes (CXCL5, TLR4, JUN, IL6, CCL2, CXCL2, ILA, IFNG, IL33, and GAPDH) in protein-protein interaction network of NARCDs and immune-related genes were all immune-related genes. Conclusion The NARCDs prognostic signature based on the above 16 genes is an independent prognostic factor, which can effectively predict the clinical prognosis of patients of lung adenocarcinoma and provide help for clinical treatment.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Morte Celular Regulada , Humanos , Prognóstico , Apoptose , Adenocarcinoma de Pulmão/genética , Neoplasias Pulmonares/genética , Microambiente Tumoral
14.
Ann Surg Oncol ; 29(13): 8214-8224, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35798893

RESUMO

BACKGROUND: The benefit of adjuvant chemotherapy (AC) for patients with stage II gastric cancer remains controversial. This study aimed to explore the indications for adjuvant chemotherapy in patients with stage II gastric cancer by constructing an individual prediction model. PATIENTS AND METHODS: In this Chinese multicenter study, a total of 1012 patients with stage II gastric cancer after D2 radical gastrectomy were retrospectively analyzed. All patients were randomly assigned to a training cohort (n = 674) or a validation cohort (n = 338). A nomogram was constructed according to the training cohort. Concordance index (C-index), the area under the receiver operating characteristic (ROC) curves (AUC), calibration curves, and decision curve analysis (DCA) were applied to evaluate the performance of the nomogram. ROC curves and stratified survival were used to determine the patients' cutoff score for a benefit from adjuvant chemotherapy. An additional 338 patients were used as a validation cohort to validate the feasibility of using this nomogram to guide individualized therapy for patients with stage II gastric cancer. RESULTS: Univariate and multivariate analyses illustrated that age, sex, tumor location, size, carcinoembryonic antigen (CEA), hemoglobin (HB), and T stage were independent prognostic factors for overall survival (OS), and they were used to establish a nomogram. The cutoff value was determined by ROC curve analysis, and patients were divided into a high-risk group (< 239 points) and a low-risk group (≥ 239 points). There was no significant difference in the OS of low-risk patients in either the training cohort or the validation cohort. However, the OS of high-risk patients in the AC group was better than that of patients in the surgery-only group. CONCLUSIONS: This prediction model can be applied to guide treatment of patients with stage II gastric cancer. High-risk patients (< 239 points) are likely to benefit from AC after D2 radical gastrectomy.


Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/cirurgia , Estudos Retrospectivos , Gastrectomia/efeitos adversos , Quimioterapia Adjuvante , Nomogramas , China
15.
Sensors (Basel) ; 22(16)2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-36015716

RESUMO

We propose an efficient semi-analytical method capable of modeling the propagation of flexural waves on cracked plate structures with any forms of excitations, based on the same group of vibration characteristics and validated by a non-contact scanning Laser Doppler Vibrometer (LDV) system. The proposed modeling method is based on the superposition of the vibrational normal modes of the detected structure, which can be applied to analyze long-time and full-field transient wave propagations. By connecting the vibration-based transient model to a power flow analysis technique, we further analyze the transient waves on a cracked plate subjected to different excitation sources and show the influence of the damage event on the path of the propagating waves. The experimental results indicate that the proposed semi-analytical method can model the flexural waves, and through that, the crack information can be revealed.

16.
J Antimicrob Chemother ; 76(11): 2975-2982, 2021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34402512

RESUMO

BACKGROUND: Drug resistance mutation (DRM)-associated virological failure has become a critical issue for ART and the elimination of HIV. OBJECTIVES: To investigate the distribution characteristics of DRMs of HIV CRF01_AE, CRF07_BC and CRF08_BC, the predominant subtypes in China. METHODS: Patients receiving ART up to 31 August 2020 in Ganzhou in China were recruited. Full-length sequences of the HIV pol gene were amplified from patients with virological failure. DRMs and antiretroviral susceptibility were explored using the Stanford University HIV Drug Resistance Database HIVdb Program. RESULTS: Overall, 279 of 2204 patients under ART were found to have virological failure. Nine HIV subtypes were identified among 211 sequences that were amplified successfully and CRF08_BC (37.0%), CRF01_AE (26.1%) and CRF07_BC (25.6%) were the most prevalent, with mutation frequencies of 44.9% (35/78), 52.7% (29/55) and 35.2% (19/54), respectively. The most common DRMs of these three subtypes were K103N and M184V, while the mutation frequencies of M41L, D67N, K70R, K101E, V106M, Y181C, K219E, H221Y and N348I were obviously different among subtypes. The resistance levels and frequencies for antiretroviral drugs for these three subtypes were similar and resistances to nevirapine, efavirenz, lamivudine and emtricitabine were the most frequently observed. Compared with CRF01_AE and CRF07_BC, CRF08_BC had higher proportions of DRMs for NRTIs and lower frequencies of resistance to NRTIs and NNRTIs. CONCLUSIONS: The distribution characteristics of DRMs of HIV CRF01_AE, CRF07_BC and CRF08_BC were inconsistent and should be considered when selecting antiretroviral strategies, developing new drugs and controlling HIV strains containing DRMs.


Assuntos
Infecções por HIV , HIV-1 , China/epidemiologia , Farmacorresistência Viral , Genótipo , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , HIV-1/genética , Humanos , Mutação , Filogenia
17.
Cancer Cell Int ; 21(1): 422, 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34376192

RESUMO

BACKGROUND: Epithelial-mesenchymal transition (EMT) promotes migration, invasion, and metastasis of hepatocellular carcinoma (HCC) cells. The molecular mechanisms behind EMT and metastasis in HCC remain unclear. METHODS: Microarray analysis was used to identify lncRNAs expression during polarization of U937 macrophages from M2 to M1 phenotype. The expression of the identified lncRNA was compared between clinical samples of HCC tissues or adjacent normal tissues, as well as between HCC and normal liver cell lines. lnc-Ma301 was overexpressed or knocked-down in HCC cell lines, and the effects were assessed in vitro and in vivo. Interactions among lnc-Ma301 and its potential downstream targets caprin-1 were investigated in HCC cell lines. Effects of lnc-Ma301 over- and underexpression on the Akt/Erk1 signaling pathways were examined. RESULTS: Microarray analyses identified lnc-Ma301 as one of the most overexpressed long non-coding RNAs during polarization of U937 macrophages from M2 to M1 phenotype. Lnc-Ma301 showed lower expression in HCC tissues than in adjacent normal tissues, and lower expression was associated with worse prognosis. Activation of lnc-Ma301 inhibited cell proliferation, migration and EMT in HCC cell cultures, and it inhibited lung metastasis of HCC tumors in mice. Mechanistic studies suggested that lnc-Ma301 interacts with caprin-1 to inhibit HCC metastasis and EMT through Akt/Erk1 pathway. CONCLUSIONS: Lnc-Ma301 may help regulate onset and metastasis of HCC.

18.
Zhonghua Nan Ke Xue ; 26(3): 254-257, 2020 Mar.
Artigo em Zh | MEDLINE | ID: mdl-33346966

RESUMO

OBJECTIVE: To investigate the distribution of pathogenic bacteria in donor semen and the effect of bacterial infection on semen quality. METHODS: We performed bacterial culture on and counted the bacterial colonies (BC) in the semen samples collected from 4 897 sperm donors from 2008 to 2018 and divided them into groups A (BC <104 cfu/ml, n = 4 229), B (BC ≥104 cfu/ml, n = 150) and C (BC = 0 cfu/ml, n = 518). Using the biochemical reaction system of the French Biological Merry Emmanuel Company, we identified the bacterial species in group B, subjected all the semen samples to SCA computer assisted semen analysis, and compared the semen quality among different groups. RESULTS: In the 4 897 semen samples, hybrid bacterial contamination was found in 6 (0.12%) and non-hybrid bacteria in 4 379 (89.42%), including 150 (3.43%) in group B. In the semen samples with BC ≥104 cfu/ml, Gram-negative (G-) bacteria were observed in 104 (69.33%), mainly including Escherichia coli, followed by Proteusbacillus vulgaris and Enterobacteria, Gram-positive cocci (G+) in 39 (26.00%), G- bacteria in 4 (2.67%) and Neisseria gonorrhoeae in 3 (2.00%). Compared with group C, groups A and B showed remarkably reduced total sperm count (P < 0.05) and percentage of progressively motile sperm (P < 0.05) but no statistically significant differences in the semen liquefaction time, semen PH value, total sperm motility or the percentage of morphologically normal sperm (P > 0.05). CONCLUSIONS: Bacterial culture of donor semen revealed a positive rate of 89.42% and varied the bacterial species, mainly including G- bacteria. And the semen quality decreased with the increase of bacterial colonies.


Assuntos
Bactérias/isolamento & purificação , Análise do Sêmen , Sêmen/microbiologia , Bactérias/classificação , Humanos , Masculino , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Espermatozoides
19.
Med Sci Monit ; 25: 6539-6546, 2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31472071

RESUMO

BACKGROUND Long non-coding RNAs (lncRNAs) have been shown to play an important regulatory role in many tumors. This study was designed to investigate the expression of lncRNA ENST00000429227.1 in hepatocellular carcinoma (HCC) and to determine whether the expression of lncRNA ENST00000429227.1 affects the prognosis of HCC. MATERIAL AND METHODS lncRNA ENST00000429227.1 showing differences in expression between M1 and M2 was screened by microarray expression measurements. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of lncRNA ENST00000429227.1 in 161 HCC patients. The chi-square test was used to evaluate the relationship between the expression of ENST00000429227.1 and clinicopathological parameters. A survival curve was drawn and analyzed by Kaplan-Meier method. Cox regression was used for univariate and multivariate analysis to determine whether lncRNA ENST00000429227.1 is an independent factor of the occurrence and prognosis of HCC. RESULTS A total of 3703 differentially expressed lncRNAs were obtained, of which 1777 were upregulated and 1926 were downregulated, with multiple change >1.5. The expression of lncRNA ENST00000429227.1 was upregulated in M2 cells. The expression of lncRNA ENST00000429227.1 in HCC tissues was higher than that in adjacent normal tissues (p<0.05), which was correlated with pathological parameters such as surgical margin (p=0.042), AFP (p=0.022) and Barcelona Clinic Liver Cancer (BCLC) stage (p=0.008). Survival analysis showed that high expression of lncRNA ENST00000429227.1 was associated with a decrease in overall survival (OS) rate of HCC patients. Cox regression analysis showed that high expression of ENST00000429227.1 may be an independent risk factor affecting the prognosis of HCC patients. CONCLUSIONS The results suggest that upregulation of ENST00000429227.1 is associated with poor prognosis of HCC patients, and may be a new biomarker for the diagnosis of HCC.


Assuntos
Carcinoma Hepatocelular/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , RNA Longo não Codificante/genética , Regulação para Cima/genética , Carcinoma Hepatocelular/patologia , Feminino , Humanos , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prognóstico , Modelos de Riscos Proporcionais , RNA Longo não Codificante/metabolismo , Análise de Sobrevida
20.
J Am Chem Soc ; 140(3): 1123-1130, 2018 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-29272584

RESUMO

An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover's algorithm can be implemented in such systems. Dimetallic aza[80]fullerenes M2@C79N (M = Y or Gd) possess an unpaired electron located between two metal ions, offering an opportunity to manipulate spin(s) protected in the cage for quantum information processing. Herein, we report the crystallographic determination of Gd2@C79N for the first time. This molecular magnet with a collective high-spin ground state (S = 15/2) generated by strong magnetic coupling (JGd-Rad = 350 ± 20 cm-1) has been unambiguously validated by magnetic susceptibility experiments. Gd2@C79N has quantum coherence and diverse Rabi cycles, allowing arbitrary superposition state manipulation between each adjacent level. The phase memory time reaches 5 µs at 5 K by dynamic decoupling. This molecule fulfills the requirements of Grover's searching algorithm proposed by Leuenberger and Loss.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa