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The heterogeneity of circulating tumor cells has a significant impact on the diagnosis, treatment, and monitoring of cancer. Research on the subtypes of circulating tumor cells can bring better treatment outcomes for cancer patients. Here, we proposed a microfluidic chip for the magnetic capture of subtypes of circulating tumor cells from the whole blood and phenotypic profiling by stacking laminar flow vertically. Circulating tumor cells were sorted and captured by the three-dimensional regulation of both magnetic fields in the vertical direction and flow fields in the lateral direction. Using EpCAM-magnetic beads, we achieved sorting and sectional capture of target cells in whole blood and analyzed the surface expression levels of the captured cells, confirming the functionality of the microfluidic chip in sorting and capturing subtypes of circulating tumor cells. This microfluidic chip can also aid in the subsequent subtype analysis of other rare cells.
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OBJECTIVE: This retrospective study involving a large dataset of unilateral multifocal papillary thyroid carcinoma (UM-PTC) sought to identify factors that predict central lymph node metastases (CLNM) in patients. METHODS: We identified a cohort of 158 patients who underwent cervical ultrasonography followed by UM-PTC diagnosis based on postoperative pathology. The relationship between CLNM and UM-PTC clinical ultrasound features was evaluated using univariate and multivariate analyses. Receiver operating characteristic (ROC) curve analysis was used to determine the ability of total tumor diameter (TTD) to predict CLNM. RESULTS: Among the 158 UM-PTC patients, the incidence of CLNM was 29.7% (47/158). Univariate and multivariate analyses revealed that a number of similarity of sonographic features (NSSF) ≥4 (odds ratio [OR] = 11.335, 95% confidence interval [CI]: 3.95-32.50, p = 0.000), microcalcifications (OR = 3.54, 95% CI: 1.30-9.70, p = 0.014), a TTD of ≥2 cm (OR = 4.48, 95% CI: 1.62-12.34, p = 0.004), number of nodules ≥3 (OR = 13.17, 95% CI: 3.24-53.52, p = 0.000), and Lateral cervical lymph node metastasis (LLNM) (OR = 5.57, 95% CI: 1.59-19.48, p = 0.007) were independently associated with CLNM in UM-PTC. ROC curve analysis revealed that the TTD cut-off of 1.795 cm had a sensitivity of 0.723 and a specificity of 0.676 for predicting CLNM. CONCLUSIONS: Patients with UM-PTC are at high risk of CLNM. NSSF ≥4, microcalcifications, TTD of ≥2 cm, LLNM, and a number of nodules ≥3 were independently associated with CLNM. Our data show that ultrasound may guide surgical decisions in the treatment of UM-PTC.
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Brassinosteroid (BR) signaling leads to the nuclear accumulation of the BRASSINAZOLE-RESISTANT 1 (BZR1) transcription factor, which plays dual roles in activating or repressing the expression of thousands of genes. BZR1 represses gene expression by recruiting histone deacetylases, but how it activates transcription of BR-induced genes remains unclear. Here, we show that BR reshapes the genome-wide chromatin accessibility landscape, increasing the accessibility of BR-induced genes and reducing the accessibility of BR-repressed genes in Arabidopsis. BZR1 physically interacts with the BRAHMA-associated SWI/SNF (BAS)-chromatin-remodeling complex on the genome and selectively recruits the BAS complex to BR-activated genes. Depletion of BAS abrogates the capacities of BZR1 to increase chromatin accessibility, activate gene expression, and promote cell elongation without affecting BZR1's ability to reduce chromatin accessibility and expression of BR-repressed genes. Together, these data identify that BZR1 recruits the BAS complex to open chromatin and to mediate BR-induced transcriptional activation of growth-promoting genes.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Brasinoesteroides/metabolismo , Cromatina/genética , Cromatina/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Activación Transcripcional , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
Switch defective/sucrose non-fermentable (SWI/SNF) chromatin remodeling complexes are multi-subunit machineries that establish and maintain chromatin accessibility and gene expression by regulating chromatin structure. However, how the remodeling activities of SWI/SNF complexes are regulated in eukaryotes remains elusive. B-cell lymphoma/leukemia protein 7 A/B/C (BCL7A/B/C) have been reported as subunits of SWI/SNF complexes for decades in animals and recently in plants; however, the role of BCL7 subunits in SWI/SNF function remains undefined. Here, we identify a unique role for plant BCL7A and BCL7B homologous subunits in potentiating the genome-wide chromatin remodeling activities of SWI/SNF complexes in plants. BCL7A/B require the catalytic ATPase BRAHMA (BRM) to assemble with the signature subunits of the BRM-Associated SWI/SNF complexes (BAS) and for genomic binding at a subset of target genes. Loss of BCL7A and BCL7B diminishes BAS-mediated genome-wide chromatin accessibility without changing the stability and genomic targeting of the BAS complex, highlighting the specialized role of BCL7A/B in regulating remodeling activity. We further show that BCL7A/B fine-tune the remodeling activity of BAS complexes to generate accessible chromatin at the juvenility resetting region (JRR) of the microRNAs MIR156A/C for plant juvenile identity maintenance. In summary, our work uncovers the function of previously elusive SWI/SNF subunits in multicellular eukaryotes and provides insights into the mechanisms whereby plants memorize the juvenile identity through SWI/SNF-mediated control of chromatin accessibility.
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Cromatina , Factores de Transcripción , Animales , Cromatina/genética , Factores de Transcripción/metabolismo , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Ensamble y Desensamble de Cromatina , Expresión GénicaRESUMEN
Micro/nanospherical lens photolithography (SLPL) constitutes an efficient and precise micro/nanofabrication methodology. It offers advantages over traditional nanolithography approaches, such as cost-effectiveness and ease of implementation. By using micrometer-sized microspheres, SLPL enables the preparation of subwavelength scale features. This technique has gained attention due to its potential applications. However, the SLPL process has a notable limitation in that it mostly produces simple pattern shapes, mainly consisting of circular arrays. There has been a lack of theoretical analysis regarding the possible shapes that can be created. In our experiments, we successfully prepared annular and ring-with-hole pattern shapes. To address this limitation, we applied the Mie scattering theory to systematically analyze and summarize the various patterns that can be obtained through the SLPL process. We also proposed methods to predict and obtain different patterns. This theoretical analysis enhances the understanding of SLPL and expands its potential applications, making it a valuable area for further research.
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Background: This study sought to investigate the applicability of different ultrasound (US) thyroid risk stratification systems in diagnosing medullary thyroid carcinoma (MTC) and determining the need for biopsy. Methods: In total, 34 MTC nodules, 54 papillary thyroid carcinoma (PTC) nodules, and 62 benign thyroid nodules were examined in this study. All the diagnoses were histopathologically confirmed postoperatively. All the thyroid nodule sonographic features were recorded and categorized by 2 independent reviewers according to the Thyroid Imaging Reporting and Data System (TIRADS) of the American College of Radiology (ACR), the American Thyroid Association (ATA) guidelines, the European Thyroid Association (EU) TIRADS, the Kwak-TIRADS, and the Chinese TIRADS (C-TIRADS). The sonographic differences and risk stratifications of the MTCs, PTCs, and benign thyroid nodules were analyzed. The diagnostic performance and recommended biopsy rates for each classification system were evaluated. Results: The risk stratifications of MTCs were all higher than the benign thyroid nodules (P<0.01) and lower than PTCs (P<0.01) with each classification system. Hypoechogenicity and malignant marginal features were independent risk factors for identifying malignant thyroid nodules, and the area under the receiver operating characteristic curve (AUC) for identifying MTCs was lower than that for identifying PTCs (0.873 vs. 0.954, respectively). The AUCs, sensitivity, specificity, positive predictive values, negative predictive values, and accuracy values of the 5 systems for MTC were all lower than those for PTC. The best cut-off values for diagnosing MTC were TIRADS (TR) 4 in the ACR-TIRADS, intermediate suspicion in the ATA guidelines, TR 4 in EU-TIRADS, and TR 4b in both the Kwak-TIRADS and the C-TIRADS. The Kwak-TIRADS had the highest recommended biopsy rate for MTCs (97.1%), followed by the ATA guidelines, the EU-TIRADS (88.2%), the C-TIRADS (85.3%), and the ACR-TIRADS (79.4%). Conclusions: The US-based thyroid malignancy risk stratification systems analyzed in this study were able to satisfactorily identify MTC and recommend biopsy, but the diagnostic performance of these systems for MTC was not as good as that for PTC.
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Switch defective/sucrose nonfermentable (SWI/SNF) complexes are evolutionarily conserved multisubunit machines that play vital roles in chromatin architecture regulation for modulating gene expression via sliding or ejection of nucleosomes in eukaryotes. In plants, perturbations of SWI/SNF subunits often result in severe developmental disorders. However, the subunit composition, pathways of assembly, and genomic targeting of the plant SWI/SNF complexes are poorly understood. Here, we report the organization, genomic targeting, and assembly of 3 distinct SWI/SNF complexes in Arabidopsis thaliana: BRAHMA-Associated SWI/SNF complexes (BAS), SPLAYED-Associated SWI/SNF complexes (SAS), and MINUSCULE-Associated SWI/SNF complexes (MAS). We show that BAS complexes are equivalent to human ncBAF, whereas SAS and MAS complexes evolve in multiple subunits unique to plants, suggesting plant-specific functional evolution of SWI/SNF complexes. We further show overlapping and specific genomic targeting of the 3 plant SWI/SNF complexes on chromatin and reveal that SAS complexes are necessary for the correct genomic localization of the BAS complexes. Finally, we define the role of the core module subunit in the assembly of plant SWI/SNF complexes and highlight that ATPase module subunit is required for global complex stability and the interaction of core module subunits in Arabidopsis SAS and BAS complexes. Together, our work highlights the divergence of SWI/SNF chromatin remodelers during eukaryote evolution and provides a comprehensive landscape for understanding plant SWI/SNF complex organization, assembly, genomic targeting, and function.
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Arabidopsis , Humanos , Arabidopsis/genética , Arabidopsis/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Ensamble y Desensamble de Cromatina/genética , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Cromatina/genética , Cromatina/metabolismo , GenómicaRESUMEN
BACKGROUND: Intrathecal injection of medications can be challenging in spinal muscular atrophy (SMA) patients with severe scoliosis or after spine surgery. Here we report our experience with real-time ultrasound (US)-guided intrathecal administration of nusinersen in patients with SMA. METHODS: Seven patients (six children and one adult) with either spinal fusion or severe scoliosis were enrolled. We performed intrathecal injections of nusinersen under US guidance. The efficacy and safety of US-guided injection were explored. RESULTS: Five patients had undergone spinal fusion, while the other two presented severe scoliosis. Success was achieved in 19/20 lumbar punctures (95%), 15 of which were performed through the near-spinous process approach. The intervertebral space with a designated channel was selected for the five postoperative patients, while the interspaces with the smallest rotation angle were chosen for the other two patients with severe scoliosis. In 89.5% (17/19) of the punctures, the number of insertions was no more than two. No major adverse events were observed. CONCLUSION: Given its safety and efficacy, real-time US guidance is recommended for SMA patients with spine surgery or severe scoliosis, and the near-spinous process view can be used as a interlaminar puncture approach for US guidance.
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Atrofia Muscular Espinal , Escoliosis , Fusión Vertebral , Niño , Adulto , Humanos , Escoliosis/tratamiento farmacológico , Escoliosis/cirugía , Atrofia Muscular Espinal/tratamiento farmacológico , Atrofia Muscular Espinal/cirugía , Ultrasonografía IntervencionalRESUMEN
Intracellular delivery and genetic modification have brought a significant revolutionary to tumor immunotherapy, yet existing methods are still limited by low delivery efficiency, poor throughput, excessive cell damage, or unsuitability for suspension immune cells, specifically the natural killer cell, which is highly resistant to transfection. Here, we proposed a vibration-assisted nanoneedle/microfluidic composite system that uses large-area nanoneedles to rapidly puncture and detach the fast-moving suspension cells in the microchannel under vibration to achieve continuous high-throughput intracellular delivery. The nanoneedle arrays fabricated based on the large-area self-assembly technique and microchannels can maximize the delivery efficiency. Cas9 ribonucleoprotein complexes (Cas9/RNPs) can be delivered directly into cells due to the sufficient cellular membrane nanoperforation size; for difficult-to-transfect immune cells, the delivery efficiency can be up to 98%, while the cell viability remains at about 80%. Moreover, the throughput is demonstrated to maintain a mL/min level, which is significantly higher than that of conventional delivery techniques. Further, we prepared CD96 knockout NK-92 cells via this platform, and the gene-edited NK-92 cells possessed higher immunity by reversing exhaustion. The high-throughput, high-efficiency, and low-damage performance of our intracellular delivery strategy has great potential for cellular immunotherapy in clinical applications.
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Edición Génica , Microfluídica , Supervivencia Celular , Edición Génica/métodos , Transfección , Vibración , Inmunoterapia/métodos , Humanos , Antígenos CD/genética , Antígenos CD/uso terapéutico , Ribonucleoproteínas/genética , Ribonucleoproteínas/uso terapéutico , Tratamiento Basado en Trasplante de Células y Tejidos/métodosRESUMEN
Background: Although echogenic foci may raise malignancy rates in thyroid nodules, the association between peripheral calcification or macrocalcification and thyroid carcinoma is controversial. We evaluated the malignancy probability of various echogenic foci and explored whether the method of determining a thyroid nodule's point score in the echogenic focus category of the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) is reasonable. Methods: We retrospectively evaluated 819 patients with 852 nodules. The patterns of echogenic foci on ultrasonography were classified into the following four categories: punctate echogenic foci, macrocalcification, peripheral calcification, and multiple different types of echogenic foci. The core needle biopsy results were divided into two groups: benign and malignant or suspicious for malignancy. Results: Among the 852 nodules, 471 (55.3%) had echogenic foci on ultrasonography. Of these nodules, there was no significant statistical difference in the malignant or suspicious for malignancy rate between nodules with peripheral calcification and those with macrocalcification [40.0% (8/20) vs. 30.6% (11/36), respectively; p = 0.474]. The incidence of malignancy or suspicious for malignancy for nodules with peripheral calcification, macrocalcification, or multiple different types of echogenic foci was significantly lower than the incidence for punctate echogenic foci alone, with odds ratios of 0.265 [95% confidence interval (CI): 0.105-0.667; p = 0.005], 0.175 (95% CI: 0.083-0.368; p = 0.000), and 0.256 (95% CI: 0.136-0.482; p = 0.000), respectively. Conclusion: We found no significant statistical difference in the risk of malignancy or suspicious for malignancy rate between peripheral calcification and macrocalcification in thyroid nodules. We observed that nodules with multiple different types of echogenic foci were not associated with higher malignant or suspicious for malignancy rates compared with nodules with punctate echogenic foci alone.
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PICKLE (PKL) is a chromodomain helicase DNA-binding domain 3 (CHD3) chromatin remodeler that plays essential roles in controlling the gene expression patterns that determine developmental identity in plants, but the molecular mechanisms through which PKL is recruited to its target genes remain elusive. Here, we define a cis-motif and trans-acting factors mechanism that governs the genomic occupancy profile of PKL in Arabidopsis thaliana. We show that two homologous trans-factors VIVIPAROUS1/ABI3-LIKE1 (VAL1) and VAL2 physically interact with PKL in vivo, localize extensively to PKL-occupied regions in the genome, and promote efficient PKL recruitment at thousands of target genes, including those involved in seed maturation. Transcriptome analysis and genetic interaction studies reveal a close cooperation of VAL1/VAL2 and PKL in regulating gene expression and developmental fate. We demonstrate that this recruitment operates at two master regulatory genes, ABSCISIC ACID INSENSITIVE3 and AGAMOUS-LIKE 15, to repress the seed maturation program and ensure the seed-to-seedling transition. Together, our work unveils a general rule through which the CHD3 chromatin remodeler PKL binds to its target chromatin in plants.
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Proteínas de Arabidopsis , Arabidopsis , Ácido Abscísico/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cromatina/genética , Cromatina/metabolismo , ADN/metabolismo , ADN Helicasas/genética , ADN Helicasas/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Semillas/genética , Transactivadores/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Metallic nanoparticles (NPs) play a significant role in nanocatalytic systems, which are important for clean energy conversion, storage, and utilization. Laser fabrication of metallic NPs relying on light-matter interactions provides many opportunities. It is essential to study the atomic structure transformation of nonactive monocrystalline metallic NPs for practical applications. The high-density stacking faults were fabricated in monocrystalline Au NPs through tuning the ultrafast laser-induced relaxation dynamics, and the thermal and dynamic stress effects on the atomic structure transformation were revealed. The atomic structure transformation mainly arises from the thermal effect, and the dynamic stress distribution induced by local energy deposition gives rise to the generation of stacking faults. Au NPs with abundant stacking faults show enhanced surface activity owing to their low coordination number. We suggest that this work expands the knowledge of laser-metallic nanomaterial interactions and provides a method for designing metallic NPs for a wide range of applications.
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OBJECTIVE: To evaluate the 2015 American Thyroid Association (ATA) guidelines and 2017 American College of Radiology (ACR) Thyroid Imaging, Reporting and Data System (TI-RADS) for their efficacy in predicting malignant thyroid nodules and safety in recommending fine needle aspiration (FNA). METHODS: We reviewed data of 970 thyroid nodules from 908 patients with core needle biopsy pathology. We calculated the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for each guideline to predict malignancies. We compared the areas under the curve and FNA recommendations between the 2 guidelines. RESULTS: According to the core needle biopsy pathology, 59.9% (581/970) of the thyroid nodules were malignant. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value was 68%, 91%, 33%, 67%, and 70%, respectively, for the ATA guidelines and 70%, 84%, 49%, 71%, and 68%, respectively, for the ACR TI-RADS. Areas under the curve (ATA: 0.71 vs ACR TI-RADS: 0.74; P = .054) were similar when predicting malignancies. For the 545 nodules with maximum diameter ≥1.0 cm, the ACR TI-RADS recommended FNA less often than the ATA guidelines (83.3% [454/545] vs 87.7% [478/545]; P = .01). For the 321 malignant nodules with maximum diameter ≥1.0 cm, the proportions of FNA recommendations were not significantly different (ACR TI-RADS: 90.7% [291/321] vs ATA: 92.5% [297/321]; P = .06). CONCLUSION: The 2015 ATA guidelines and 2017 ACR TI-RADS showed a similar ability in predicting malignancies. Reducing FNA recommendations by the ACR TI-RADS would not lead to a significant decrease in the FNA recommendations given for malignancies with maximum diameter ≥1.0 cm.
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Radiología , Nódulo Tiroideo , Sistemas de Datos , Humanos , Estudios Retrospectivos , Nódulo Tiroideo/diagnóstico por imagen , Ultrasonografía , Estados UnidosRESUMEN
Switch defective/sucrose non-fermentable (SWI/SNF) chromatin remodeling complexes are multi-subunit machines that play vital roles in the regulation of chromatin structure and gene expression. However, the mechanisms by which SWI/SNF complexes recognize their target loci in plants are not fully understood. Here, we show that the Arabidopsis thaliana bromodomain-containing proteins BRD1, BRD2, and BRD13 are core subunits of SWI/SNF complexes and critical for SWI/SNF genomic targeting. These three BRDs interact directly with multiple SWI/SNF subunits, including the BRAHMA (BRM) catalytic subunit. Phenotypic and transcriptomic analyses of the brd1 brd2 brd13 triple mutant revealed that these BRDs act largely redundantly to control gene expression and developmental processes that are also regulated by BRM. Genome-wide occupancy profiling demonstrated that these three BRDs extensively colocalize with BRM on chromatin. Simultaneous loss of function of three BRD genes results in reduced BRM protein levels and decreased occupancy of BRM on chromatin across the genome. Furthermore, we demonstrated that the bromodomains of BRDs are essential for genomic targeting of the BRD subunits of SWI/SNF complexes to their target sites. Collectively, these results demonstrate that BRD1, BRD2, and BRD13 are core subunits of SWI/SNF complexes and reveal their biological roles in facilitating genomic targeting of BRM-containing SWI/SNF complexes in plants.
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Adenosina Trifosfatasas/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Ensamble y Desensamble de Cromatina , Proteínas Cromosómicas no Histona/metabolismo , Factores de Transcripción/metabolismo , Adenosina Trifosfatasas/genética , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Cromatina/metabolismo , Proteínas Cromosómicas no Histona/química , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Factores de Transcripción/químicaRESUMEN
OBJECTIVE: To evaluate the diagnostic performance of preoperative contrast-enhanced ultrasound (CEUS) in the detection of extracapsular extension (ECE) and cervical lymph node metastasis (LNM) of papillary thyroid carcinoma (PTC) and the added value of CEUS in the evaluation of PTC invasiveness to conventional ultrasound (US). MATERIALS AND METHODS: A total of 62 patients were enrolled retrospectively, including 30 patients with invasive PTCs (Group A, ECE or LNM present) and 32 patients with non-invasive PTCs (Group B). All patients underwent US and CEUS examinations before surgery. US and CEUS features of PTCs and lymph nodes were compared between groups. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of US, CEUS, and the combination of the two in the detection of ECE and LNM of PTCs were calculated. Logistic regression was used to analyze relationships between variables. RESULTS: The PTC size was larger in group A on both US and CEUS (P = 0.001, P = 0.003). More PTCs showed hyper-enhancement in group A (P = 0.013) than in group B. More PTCs had >25% contact between PTC and the thyroid capsule and discontinued capsule on US and CEUS (all P < 0.05) in group A than in group B. More absent hilum and calcification of lymph nodes were observed in group A (both P < 0.05) than in group B on US. More centripetal perfusion and enlarged lymph nodes were observed in group A (both P < 0.05) than in group B on CEUS. CEUS alone and US combined with CEUS manifested higher diagnostic accuracy (79.0%) than US alone (72.6%) in the detection of ECE. The combination of US and CEUS manifested the highest diagnostic accuracy (95.2%) than CEUS alone (90.3%) and US alone (82.2%) in the detection of LNM. Diagnoses of ECE and LNM by the combination of US and CEUS were independent risk factors for PTC invasiveness [odds ratio (OR) = 29.49 and 97.20, respectively; both P = 0.001]. CONCLUSION: CEUS or US combined with CEUS is recommended for the detection of PTC ECE, while the combination of US and CEUS is most recommended for LNM detection. CEUS plays an essential role in the preoperative evaluation of PTC invasiveness.
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Aims: mcr-1 and blaNDM-1 co-harboring isolates have been reported, usually reside on different plasmids, suggesting co-transfer possibility of the two genes from separate donors to the same recipient strain. This study aims at screening and characterization of mcr-1 carrying Enterobacteriaceae in Northern China, and studying the transfer ability of mcr-1 alone and in company with blaNDM-1 from a second donor. Results: Three Escherichia coli strains and one Klebsiella pneumoniae strain carrying mcr-1 gene were screened out from 1992 isolates in our study. Co-existence of multiple resistance genes was found in the mcr-1-carrying strains, but none of them carried blaNDM-1. One E. coli demonstrated an single nucleotide polymorphism (SNP) (A-G) at -10 region of mcr-1, and one E. coli showed 2 SNPs (G-T and G-A) in the Shine-Dalgarno sequence-like region of mcr-1. The mcr-1 gene was located on plasmids of about 33-276 kb, and capable of transferring alone in three out of four mcr-1-positive isolates by conjugation. Co-transfer ability analysis demonstrated that mcr-1 from E. coli 13-68, which could not be transferred alone to E. coli C600, was successfully transferred in company with blaNDM-1 from K. pneumoniae ATCC BAA-2146. Conclusions: mcr-1 showed low incidence in our Enterobacteriaceae isolates. Co-transfer ability of mcr-1 and blaNDM-1 from separate donors provides direct evidence for the emergence of the mcr-1 and blaNDM-1 co-harboring isolates.
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Farmacorresistencia Bacteriana Múltiple/genética , Enterobacteriaceae/genética , Escherichia coli/genética , Genes Bacterianos/genética , Klebsiella pneumoniae/genética , Humanos , Pruebas de Sensibilidad Microbiana , Polimorfismo de Nucleótido Simple , Reacción en Cadena en Tiempo Real de la Polimerasa , beta-Lactamasas/genéticaRESUMEN
The Polycomb repressive complex 2 (PRC2) catalyzes histone H3 Lys27 trimethylation (H3K27me3) to repress gene transcription in multicellular eukaryotes. Despite its importance in gene silencing and cellular differentiation, how PRC2 is recruited to target loci is still not fully understood. Here, we report genome-wide evidence for the recruitment of PRC2 by the transcriptional repressors VIVIPAROUS1/ABI3-LIKE1 (VAL1) and VAL2 in Arabidopsis thaliana. We show that the val1 val2 double mutant possesses somatic embryonic phenotypes and a transcriptome strikingly similar to those of the swn clf double mutant, which lacks the PRC2 catalytic subunits SWINGER (SWN) and CURLY LEAF (CLF). We further show that VAL1 and VAL2 physically interact with SWN and CLF in vivo. Genome-wide binding profiling demonstrated that they colocalize with SWN and CLF at PRC2 target loci. Loss of VAL1/2 significantly reduces SWN and CLF enrichment at PRC2 target loci and leads to a genome-wide redistribution of H3K27me3 that strongly affects transcription. Finally, we provide evidence that the VAL1/VAL2-RY regulatory system is largely independent of previously identified modules for Polycomb silencing in plants. Together, our work demonstrates an extensive genome-wide interaction between VAL1/2 and PRC2 and provides mechanistic insights into the establishment of Polycomb silencing in plants.
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Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas , Silenciador del Gen , Complejo Represivo Polycomb 2/metabolismo , Proteínas Represoras/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Represión Epigenética , Ontología de Genes , Histonas/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Complejo Represivo Polycomb 2/genética , Unión Proteica , Mapeo de Interacción de Proteínas , Proteínas Represoras/deficiencia , Proteínas Represoras/genética , Elementos de Respuesta/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transcripción GenéticaRESUMEN
Seed dormancy is an adaptive trait that is crucial to plant survival. Abscisic acid (ABA) is the primary phytohormone that induces seed dormancy. However, little is known about how the level of ABA in seeds is determined. Here we show that the Arabidopsis (Arabidopsis thaliana) H3K27me3 demethylase RELATIVE OF EARLY FLOWERING6 (REF6) suppresses seed dormancy by inducing ABA catabolism in seeds. Seeds of the ref6 loss-of-function mutants displayed enhanced dormancy that was associated with increased endogenous ABA content. We further show that the transcripts of two genes key to ABA catabolism, CYP707A1 and CYP707A3, but not genes involved in ABA biosynthesis, were significantly reduced in ref6 mutants during seed development and germination. In developing siliques, REF6 bound directly to CYP707A1 and CYP707A3, and was responsible for reducing their H3K27me3 levels. Genetic analysis demonstrated that the enhanced seed dormancy and ABA concentration in ref6 depended mainly on the reduced expression of CYP707A1 and CYP707A3 Conversely, overexpression of CYP707A1 could offset the enhanced seed dormancy of ref6 Taken together, our results revealed an epigenetic regulation mechanism that is involved in the regulation of ABA content in seeds.
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Ácido Abscísico/metabolismo , Arabidopsis/genética , Arabidopsis/fisiología , Epigénesis Genética , Germinación/genética , Latencia en las Plantas/genética , Latencia en las Plantas/fisiología , Regulación de la Expresión Génica de las Plantas , Genes de PlantasRESUMEN
Switch defective/sucrose non-fermentable (SWI/SNF) chromatin remodelling complexes are multi-protein machineries that control gene expression by regulating chromatin structure in eukaryotes. However, the full subunit composition of SWI/SNF complexes in plants remains unclear. Here we report that in Arabidopsis thaliana, two homologous glioma tumour suppressor candidate region domain-containing proteins, named BRAHMA-interacting proteins 1 (BRIP1) and BRIP2, are core subunits of plant SWI/SNF complexes. brip1 brip2 double mutants exhibit developmental phenotypes and a transcriptome remarkably similar to those of BRAHMA (BRM) mutants. Genetic interaction tests indicated that BRIP1 and BRIP2 act together with BRM to regulate gene expression. Furthermore, BRIP1 and BRIP2 physically interact with BRM-containing SWI/SNF complexes and extensively co-localize with BRM on chromatin. Simultaneous mutation of BRIP1 and BRIP2 results in decreased BRM occupancy at almost all BRM target loci and substantially reduced abundance of the SWI/SNF assemblies. Together, our work identifies new core subunits of BRM-containing SWI/SNF complexes in plants and uncovers the essential role of these subunits in maintaining the abundance of SWI/SNF complexes in plants.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Ensamble y Desensamble de Cromatina , Cromatina/metabolismo , Proteínas Nucleares/metabolismo , Piruvato Quinasa/metabolismo , Adenosina Trifosfatasas/metabolismo , Arabidopsis/metabolismo , Proteínas Cromosómicas no Histona , Factores Generales de TranscripciónRESUMEN
Seed is vital to the conservation of germplasm and plant biodiversity. Seed dormancy is an adaptive trait in numerous seed-plant species, enabling plants to survive under stressful conditions. Seed dormancy is mainly controlled by abscisic acid (ABA) and gibberellin (GA) and can be classified as primary and secondary seed dormancy. The primary seed dormancy is induced by maternal ABA. Here we found that AtPER1, a seed-specific peroxiredoxin, is involved in enhancing primary seed dormancy. Two loss-of-function atper1 mutants, atper1-1 and atper1-2, displayed suppressed primary seed dormancy accompanied with reduced ABA and increased GA contents in seeds. Furthermore, atper1 mutant seeds were insensitive to abiotic stresses during seed germination. The expression of several ABA catabolism genes (CYP707A1, CYP707A2, and CYP707A3) and GA biosynthesis genes (GA20ox1, GA20ox3, and KAO3) in atper1 mutant seeds was increased compared to wild-type seeds. The suppressed primary seed dormancy of atper1-1 was completely reduced by deletion of CYP707A genes. Furthermore, loss-of-function of AtPER1 cannot enhance the seed germination ratio of aba2-1 or ga1-t, suggesting that AtPER1-enhanced primary seed dormancy is dependent on ABA and GA. Additionally, the level of reactive oxygen species (ROS) in atper1 mutant seeds was significantly higher than that in wild-type seeds. Taken together, our results demonstrate that AtPER1 eliminates ROS to suppress ABA catabolism and GA biosynthesis, and thus improves the primary seed dormancy and make the seeds less sensitive to adverse environmental conditions.