Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 326
Filtrar
1.
Adv Mater ; : e2102560, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34632642

RESUMO

Phase transitions are universal in solid-state matters, as well as in periodic electromagnetic metasurfaces - the photonic analogues of crystals. Although such transitions dictate the properties of active metasurfaces, universal ways to describe the structure transition of periodic metasurfaces have not yet been established. Here, we report the strain-enable phase transition (or lattice deformation) of stretchable metasurfaces with the crystallographic description. We analytically and experimentally demonstrate the phase transition of plasmonic lattices between two arbitrary two-dimensional (2D) Bravais lattices under certain strain configurations. The strain-induced symmetry lowering of the structures gives rise to optical anisotropy upon polarization, namely, linearly and circularly polarized dichroism. We further demonstrate the potential of phase transition in information decoding with applied strain. Interpreting the phase transition of metesurfaces from a standpoint of symmetry would accelerate the discovery of emergent properties, and provide a generalizable approach to designing active metasurfaces. This article is protected by copyright. All rights reserved.

2.
Sci Total Environ ; 807(Pt 1): 150737, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34606860

RESUMO

Biological wastewater treatment is a process in which the microbial metabolism of complex communities transforms pollutants into low- or non-toxic products. Due to the absence of an in-depth understanding of the diversity and complexity of microbial communities, it is very likely to ignore the potential mechanisms of microbial community in wastewater treatment. Metagenomics is a technology based on molecular biology, in which massive gene sequences are obtained from environmental samples and analyzed by bioinformatics to determine the composition and function of a microbial community. Metagenomics can identify the state of microbes in their native environments more effectively than traditional molecular methods. This review summarizes the application of metagenomics to assess microbial communities in biological wastewater treatment, such as the biological removal of phosphorus and nitrogen by bacteria, the study of antibiotic resistance genes (ARGs), and the reduction of heavy metals by microbial communities, with an emphasis on the contribution of microbial diversity and metabolic diversity. Technical bottlenecks in the application of metagenomics to biological wastewater treatment are elucidated, and future research directions for metagenomics are proposed, among which the application of multi-omics will be an important research method for future biological wastewater treatment.

3.
J Colloid Interface Sci ; 607(Pt 1): 24-33, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34492350

RESUMO

The aimlessness in the selection of dielectric absorbing materials and the regulation of complex permittivity consumes time and resources. It is an effective way to construct electromagnetic wave (EMW)-absorbing materials dominated by dielectric loss to select materials and adjust complex permittivity based on theory. With sulfide as an example, a hollow ZnO/ZnS composite was constructed using ZnO as a hard template. Subsequently, based on the diverse binding ability of Cu and Zn ions to S ions, the compositions, interfaces, and defects of the sample were simultaneously regulated. There was competition and synergy between the relaxation process caused by the defects and interfaces and the conductivity loss, resulting in the regulation of complex permittivity. Furthermore, the hollow structure effectively reduced the density of the material and improved the impedance matching ability of the sample. As a result, the effective absorption bandwidth (EAB) of the hollow nanoflower ZnO/ZnS/CuS composite reached 5.2 GHz (from 12.8 to 18 GHz) with a matching thickness of 1.59 mm. This method provides a direction for ameliorating the complex permittivity of EMW-absorbing materials dominated by dielectric loss to realize broadband absorption.

4.
Biosens Bioelectron ; 194: 113614, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34500225

RESUMO

The performance of bioelectrochemical systems (BESs) is significantly influenced by metabolic interactions within a particular microbial community. Although some studies show that interspecific metabolic cooperation benefits BESs performance, the effect of interspecific substrate competition on BESs performance has not yet been discussed. Herein, the impact of interspecific competition is investigated by monitoring the extracellular electron transfer of exoelectrogenic Shewanella oneidensis MR-1 and non-exoelectrogenic Citrobacter freundii An1 alone and simultaneously. The bacterial consortia generate the highest current of 38.4 µA cm-2, 6 times of that produced by the single strain S. oneidensis MR-1. Though S. oneidensis MR-1 loses out to C. freundii An1 in solution, the competition enhances the metabolic activity of S. oneidensis MR-1 on electrode, which facilitates the biofilm formation and therefore helps S. oneidensis MR-1 to gain an competitive advantage over C. freundii An1. Increased metabolic activity triggers more electrons generation and flavin secretion of S. oneidensis MR-1 which contributes to its excellent exoelectrogenic capacity. The proteomics analysis confirms that the expression of proteins related to lactate metabolism, biofilm formation, and outer membrane c-type cytochromes are significantly upregulated in S. oneidensis MR-1 from bacterial consortia.

5.
Med Image Anal ; 74: 102205, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34425317

RESUMO

With the global outbreak of COVID-19 in early 2020, rapid diagnosis of COVID-19 has become the urgent need to control the spread of the epidemic. In clinical settings, lung infection segmentation from computed tomography (CT) images can provide vital information for the quantification and diagnosis of COVID-19. However, accurate infection segmentation is a challenging task due to (i) the low boundary contrast between infections and the surroundings, (ii) large variations of infection regions, and, most importantly, (iii) the shortage of large-scale annotated data. To address these issues, we propose a novel two-stage cross-domain transfer learning framework for the accurate segmentation of COVID-19 lung infections from CT images. Our framework consists of two major technical innovations, including an effective infection segmentation deep learning model, called nCoVSegNet, and a novel two-stage transfer learning strategy. Specifically, our nCoVSegNet conducts effective infection segmentation by taking advantage of attention-aware feature fusion and large receptive fields, aiming to resolve the issues related to low boundary contrast and large infection variations. To alleviate the shortage of the data, the nCoVSegNet is pre-trained using a two-stage cross-domain transfer learning strategy, which makes full use of the knowledge from natural images (i.e., ImageNet) and medical images (i.e., LIDC-IDRI) to boost the final training on CT images with COVID-19 infections. Extensive experiments demonstrate that our framework achieves superior segmentation accuracy and outperforms the cutting-edge models, both quantitatively and qualitatively.

6.
Artigo em Inglês | MEDLINE | ID: mdl-34404015

RESUMO

Hypoxia negatively affects the behavior, immunology, physiology, and growth of fish. Therefore, uncovering the genetic mechanisms underlying hypoxia adaptation and tolerance in fish prior to any genetic improvement is essential. Bighead carp is one of the most important freshwater fish species in aquaculture worldwide; however, this species does not have a strong ability to tolerate hypoxia. In this study, the dissolved oxygen level (0.6 mg/L) was maintained above the asphyxiation point of bighead carp for a long time to simulate hypoxia stress. The liver, gills, and heart were sampled before (0 h) and after (1 h, 2 h, 4 h) the hypoxia tests. Glutathione peroxidase (GPx) and catalase (CAT) activities and malondialdehyde (MDA) levels in the liver were significantly (p < 0.05) elevated at 1 h after hypoxic stress. By observing tissue morphology, the cell structure of the liver and gill tissues was found to change to varying degrees before and after hypoxia stress. Transcriptome sequencing was performed on 36 samples of gill, liver, and heart at four time points, and a total of 293.55G of data was obtained. In the early phase (0-1 h), differentially expressed genes (DEGs, 807 genes upregulated, 654 genes downregulated) were mainly enriched in signal transduction, such as cytokine-cytokine receptor interactions and ECM-receptor interactions. In the middle phase (0-2 h), DEGs (1201 genes upregulated and 2036 genes downregulated) were mainly enriched in regulation and adaptation, such as the MAPK and FoxO signaling pathways. Finally, in the later phase (0-4 h), DEGs (3975 genes upregulated and 4412 genes downregulated) were mainly enriched in tolerance and apoptosis, such as the VEGF signaling pathway and apoptosis. The genes with the most remarkable upregulation at different time points in the three tissues had some similarities. Genetic differences in these genes may be responsible for the differences in hypoxia tolerance among individuals. Altogether, our study provides new insights into the molecular mechanisms of hypoxia adaptation in fish. Further, the key regulatory genes identified provide genetic resources for breeding hypoxia-tolerant bighead carp species.

7.
ACS Synth Biol ; 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34415729

RESUMO

2'-Fucosyllactose (2'-FL) has been widely used as a nutritional additive in infant formula due to its multifarious nutraceutical and pharmaceutical functions in neonate health. As such, it is essential to develop an efficient and extensive microbial fermentation platform to cater to the needs of the 2'-FL market. In this study, a spatial synthetic biology strategy was employed to promote 2'-FL biosynthesis in recombinant Escherichia coli. First, the salvage pathway for 2'-FL production from l-fucose and lactose was constructed by introducing a bifunctional enzyme l-fucokinase/GDP-l-fucose pyrophosphorylase (Fkp) derived from Bacteroides fragilis and an α-1,2-fucosyltransferase (FutC) derived from Helicobacter pylori into engineered E. coli BL21(DE3). Next, the endogenous genes involved in the degradation and shunting of the substrate and key intermediate were inactivated to improve the availability of precursors for 2'-FL biosynthesis. Moreover, to further improve the yield and titer of 2'-FL, a short peptide pair (RIAD-RIDD) was used to form self-assembling multienzyme complexes in vivo. The spatial localization of peptides and stoichiometry of enzyme assemblies were subsequently optimized to further improve 2'-FL production. Finally, cofactor regeneration was also considered to alleviate the potential cofactor deficiency and redox flux imbalance in the biocatalysis process. Fed-batch fermentation of the final WLS20 strain accumulated 30.5 g/L extracellular 2'-FL with the yield and productivity of 0.661 mol/mol fucose and 0.48 g/L/h, respectively. This research has demonstrated that the application of spatial synthetic biology and metabolic engineering strategies can dramatically enlarge the titer and yield of 2'-FL biosynthesis in engineered E. coli.

8.
J Clin Endocrinol Metab ; 106(10): e3852-e3864, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34214160

RESUMO

CONTEXT: Several small studies have suggested that the gut microbiome might influence osteoporosis, but there is little evidence from human metabolomics studies to explain this association. OBJECTIVE: This study examined the association of gut microbiome dysbiosis with osteoporosis and explored the potential pathways through which this association occurs using fecal and serum metabolomics. METHODS: We analyzed the composition of the gut microbiota by 16S rRNA profiling and bone mineral density using dual-energy X-ray absorptiometry in 1776 community-based adults. Targeted metabolomics in feces (15 categories) and serum (12 categories) were further analyzed in 971 participants using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. RESULTS: This study showed that osteoporosis was related to the beta diversity, taxonomy, and functional composition of the gut microbiota. The relative abundance of Actinobacillus, Blautia, Oscillospira, Bacteroides, and Phascolarctobacterium was positively associated with osteoporosis. However, Veillonellaceae other, Collinsella, and Ruminococcaceae other were inversely associated with the presence of osteoporosis. The association between microbiota biomarkers and osteoporosis was related to levels of peptidases and transcription machinery in microbial function. Fecal and serum metabolomics analyses suggested that tyrosine and tryptophan metabolism and valine, leucine, and isoleucine degradation were significantly linked to the identified microbiota biomarkers and to osteoporosis, respectively. CONCLUSION: This large population-based study provided robust evidence connecting gut dysbiosis, fecal metabolomics, and serum metabolomics with osteoporosis. Our results suggest that gut dysbiosis and amino acid metabolism could be targets for intervention in osteoporosis.

9.
Cancer Sci ; 112(9): 3555-3568, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34255396

RESUMO

The long reads of Nanopore sequencing permit accurate transcript assembly and ease in discovering novel transcripts with potentially important functions in cancers. The wide adoption of Nanopore sequencing for transcript quantification, however, is largely limited by high costs. To address this issue, we developed a bioinformatics software, NovelQuant, that can specifically quantify long-read-assembled novel transcripts with short-read sequencing data. Nanopore Direct RNA Sequencing was carried out on three hepatocellular carcinoma (HCC) patients' tumor, matched portal vein tumor thrombus, and peritumor to reconstruct the HCC transcriptome. Then, based on the reconstructed transcriptome, NovelQuant was applied on Illumina RNA sequencing data of 59 HCC patients' tumor and paired peritumor to quantify novel transcripts. Our further analysis revealed 361 novel transcripts dysregulated in HCC and that 101 of them were significantly associated with prognosis. There were 19 novel prognostic transcripts predicted to be long noncoding RNAs (lncRNAs), and some of them had regulatory targets that were reported to be associated with HCC. Additionally, 42 novel prognostic transcripts were predicted to be protein-coding mRNAs, and many of them could be involved in xenobiotic metabolism. Moreover, the tumor-suppressive roles of two representative novel prognostic transcripts, CDO1-novel (lncRNA) and CYP2A6-novel (protein-coding mRNA), were further functionally validated during HCC progression. Overall, the current study shows a possibility of combining long- and short-read sequencing to explore functionally important novel transcripts in HCC with accuracy and cost-efficiency, which expands the pool of molecular biomarkers that could enhance our understanding of the molecular mechanisms of HCC.


Assuntos
Carcinoma Hepatocelular/genética , Confiabilidade dos Dados , Neoplasias Hepáticas/genética , Sequenciamento por Nanoporos/métodos , Análise de Sequência de RNA/métodos , Transcriptoma , Idoso , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/cirurgia , Biologia Computacional/métodos , Progressão da Doença , Feminino , Perfilação da Expressão Gênica/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/cirurgia , Masculino , Pessoa de Meia-Idade , Prognóstico , RNA Longo não Codificante/genética , RNA Mensageiro/genética , Software
10.
Lancet ; 398(10295): 131-142, 2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34246347

RESUMO

BACKGROUND: The PI3K/AKT and androgen-receptor pathways are dysregulated in metastatic castration-resistant prostate cancers (mCRPCs); tumours with functional PTEN-loss status have hyperactivated AKT signalling. Dual pathway inhibition with AKT inhibitor ipatasertib plus abiraterone might have greater benefit than abiraterone alone. We aimed to compare ipatasertib plus abiraterone with placebo plus abiraterone in patients with previously untreated mCRPC with or without tumour PTEN loss. METHODS: We did a randomised, double-blind, phase 3 trial at 200 sites across 26 countries or regions. Patients aged 18 years or older with previously untreated asymptomatic or mildly symptomatic mCRPC who had progressive disease and Eastern Collaborative Oncology Group performance status of 0 or 1 were randomly assigned (1:1; permuted block method) to receive ipatasertib (400 mg once daily orally) plus abiraterone (1000 mg once daily orally) and prednisolone (5 mg twice a day orally) or placebo plus abiraterone and prednisolone (with the same dosing schedule). Patients received study treatment until disease progression, intolerable toxicity, withdrawal from the study, or study completion. Stratification factors were previous taxane-based therapy for hormone-sensitive prostate cancer, type of progression, presence of visceral metastasis, and tumour PTEN-loss status by immunohistochemistry. Patients, investigators, and the study sponsor were masked to the treatment allocation. The coprimary endpoints were investigator-assessed radiographical progression-free survival in the PTEN-loss-by-immunohistochemistry population and in the intention-to-treat population. This study is ongoing and is registered with ClinicalTrials.gov, NCT03072238. FINDINGS: Between June 30, 2017, and Jan 17, 2019, 1611 patients were screened for eligibility and 1101 (68%) were enrolled; 554 (50%) were assigned to the placebo-abiraterone group and 547 (50%) to the ipatasertib-abiraterone group. At data cutoff (March 16, 2020), median follow-up duration was 19 months (range 0-33). In the 521 (47%) patients who had tumours with PTEN loss by immunohistochemistry (261 in the placebo-abiraterone group and 260 in the ipatasertib-abiraterone group), median radiographical progression-free survival was 16·5 months (95% CI 13·9-17·0) in the placebo-abiraterone group and 18·5 months (16·3-22·1) in the ipatasertib-abiraterone group (hazard ratio [HR] 0·77 [95% CI 0·61-0·98]; p=0·034; significant at α=0·04). In the intention-to-treat population, median progression-free survival was 16·6 months (95% CI 15·6-19·1) in the placebo-abiraterone group and 19·2 months (16·5-22·3) in the ipatasertib-abiraterone group (HR 0·84 [95% CI 0·71-0·99]; p=0·043; not significant at α=0·01). Grade 3 or higher adverse events occurred in 213 (39%) of 546 patients in the placebo-abiraterone group and in 386 (70%) of 551 patients in the ipatasertib-abiraterone group; adverse events leading to discontinuation of placebo or ipatasertib occurred in 28 (5%) in the placebo-abiraterone group and 116 (21%) in the ipatasertib-abiraterone group. Deaths due to adverse events deemed related to treatment occurred in two patients (<1%; acute myocardial infarction [n=1] and lower respiratory tract infection [n=1]) in the placebo-abiraterone group and in two patients (<1%; hyperglycaemia [n=1] and chemical pneumonitis [n=1]) in the ipastasertb-abiraterone group. INTERPRETATION: Ipatasertib plus abiraterone significantly improved radiographical progression-free survival compared with placebo plus abiraterone among patients with mCRPC with PTEN-loss tumours, but there was no significant difference between the groups in the intention-to-treat population. Adverse events were consistent with the known safety profiles of each agent. These data suggest that combined AKT and androgen-receptor signalling pathway inhibition with ipatasertib and abiraterone is a potential treatment for men with PTEN-loss mCRPC, a population with a poor prognosis. FUNDING: F Hoffmann-La Roche and Genentech.

11.
J Genet Genomics ; 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-34257044

RESUMO

Gut microbial dysbiosis has been linked to many noncommunicable diseases. However, little is known about specific gut microbiota composition and its correlated metabolites associated with molecular signatures underlying host response to infection. Here, we describe the construction of a proteomic risk score based on 20 blood proteomic biomarkers, which have recently been identified as molecular signatures predicting the progression of the COVID-19. We demonstrate that in our cohort of 990 healthy individuals without infection, this proteomic risk score is positively associated with proinflammatory cytokines mainly among older, but not younger, individuals. We further discover that a core set of gut microbiota can accurately predict the above proteomic biomarkers among 301 individuals using a machine learning model and that these gut microbiota features are highly correlated with proinflammatory cytokines in another independent set of 366 individuals. Fecal metabolomics analysis suggests potential amino acid-related pathways linking gut microbiota to host metabolism and inflammation. Overall, our multi-omics analyses suggest that gut microbiota composition and function are closely related to inflammation and molecular signatures of host response to infection among healthy individuals. These results may provide novel insights into the cross-talk between gut microbiota and host immune system.

12.
Adv Mater ; 33(34): e2100221, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34278616

RESUMO

Transparent electrodes that form seamless contact and enable optical interrogation at the electrode-brain interface are potentially of high significance for neuroscience studies. Silk hydrogels can offer an ideal platform for transparent neural interfaces owing to their superior biocompatibility. However, conventional silk hydrogels are too weak and have difficulties integrating with highly conductive and stretchable electronics. Here, a transparent and stretchable hydrogel electrode based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and PEGylated silk protein is reported. PEGylated silk protein with poly(ethylene glycol) diglycidyl ether (PEGDE) improves the Young's modulus to 1.51-10.73 MPa and the stretchability to ≈400% from conventional silk hydrogels (<10 kPa). The PEGylated silk also helps form a robust interface with PEDOT:PSS thin film, making the hydrogel electrode synergistically incorporate superior stretchability (≈260%), stable electrical performance (≈4 months), and a low sheet resistance (≈160 ± 56 Ω sq-1 ). Finally, the electrode facilitates efficient electrical recording, and stimulation with unobstructed optical interrogation and rat-brain imaging are demonstrated. The highly transparent and stretchable hydrogel electrode offers a practical tool for neuroscience and paves the way for a harmonized tissue-electrode interface.

14.
ACS Nano ; 15(6): 9955-9966, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-34110782

RESUMO

Noninvasive and seamless interfacing between the sensors and human skin is highly desired for wearable healthcare. Thin-film-based soft and stretchable sensors can to some extent form conformal contact with skin even under dynamic movements for high-fidelity signals acquisition. However, sweat accumulation underneath these sensors for long-term monitoring would compromise the thermal-wet comfort, electrode adherence to the skin, and signal fidelity. Here, we report the fabrication of a highly thermal-wet comfortable and conformal silk-based electrode, which can be used for on-skin electrophysiological measurement under sweaty conditions. It is realized through incorporating conducting polymers poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT:PSS) into glycerol-plasticized silk fiber mats. Glycerol plays the role of tuning the mechanical properties of silk fiber mats and enhancing the conductivity of PEDOT:PSS. Our silk-based electrodes show high stretchability (>250%), low thermal insulation (∼0.13 °C·m2·W-1), low evaporative resistance (∼23 Pa·m2·W-1, 10 times lower than ∼1.3 mm thick commercial gel electrodes), and high water-vapor transmission rate (∼117 g·m-2·h-1 under sweaty conditions, 2 times higher than skin water loss). These features enable a better electrocardiography signal quality than that of commercial gel electrodes without disturbing the heat dissipation during sweat evaporation and provide possibilities for textile integration to monitor the muscle activities under large deformation. Our glycerol-plasticized silk-based electrodes possessing superior physiological comfortability may further engage progress in on-skin electronics with sweat tolerance.


Assuntos
Seda , Suor , Condutividade Elétrica , Eletrodos , Humanos , Pele
15.
J Ethnopharmacol ; 278: 114280, 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34082014

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Gross Saponins of Tribulus terrestris L. Fruit (GSTTF) has been reported to have a protective effect against ischemic stroke, but the related mechanism is complex and still not fully investigated. AIM OF THE STUDY: The combination of metabolomics and proteomics approach was applied to reveal the mechanisms of GSTTF in treating ischemic stroke. MATERIALS AND METHODS: The metabolite and protein changes in brain tissue were analyzed by the LC-MS-based untargeted metabolomics method and tandem mass tags (TMT)-based quantitative proteomics technology. The multivariate statistical analysis and protein-protein interaction (PPI) analysis were conducted to screen out the biomarkers, and their related pathway was further investigated by the joint pathway analysis. RESULTS: A total of 110 metabolites and 359 differential proteins, which were mainly associated with complement and coagulation cascades, sphingolipid metabolism, glycerophospholipid metabolism, glutathione metabolism, and platelet activation, etc. were screened out from the rat brain tissue. The PPI network exhibited that the protein F2, Fga, Fgb, Fgg, Plg, and C3, which are greatly involved in the complement and coagulation cascades, have a relatively high connectivity degree, indicating their importance in the process of middle cerebral artery occlusion (MCAO). The GSTTF exerted a protective effect against MCAO via modulating multiple proteins on this pathway. Moreover, F2 played a key role during the protective process and worth to be further investigated due to it has been reported as one of the therapeutic targets of ischemic stroke. CONCLUSION: The present study could improve the understanding of the potential therapeutic mechanism of GSTTF against ischemic stroke.

16.
Nat Chem Biol ; 17(6): 632-640, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34035515

RESUMO

Components of the cell division machinery typically function at varying cell cycle stages and intracellular locations. To dissect cellular mechanisms during the rapid division process, small-molecule probes act as complementary approaches to genetic manipulations, with advantages of temporal and in some cases spatial control and applicability to multiple model systems. This Review focuses on recent advances in chemical probes and applications to address select questions in cell division. We discuss uses of both enzyme inhibitors and chemical inducers of dimerization, as well as emerging techniques to promote future investigations. Overall, these concepts may open new research directions for applying chemical probes to advance cell biology.


Assuntos
Biologia Celular , Divisão Celular/fisiologia , Animais , Ciclo Celular , Técnicas Genéticas , Humanos
17.
J Cell Biol ; 220(6)2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-33904910

RESUMO

To ensure accurate chromosome segregation, interactions between kinetochores and microtubules are regulated by a combination of mechanics and biochemistry. Tension provides a signal to discriminate attachment errors from bi-oriented kinetochores with sisters correctly attached to opposite spindle poles. Biochemically, Aurora B kinase phosphorylates kinetochores to destabilize interactions with microtubules. To link mechanics and biochemistry, current models regard tension as an input signal to locally regulate Aurora B activity. Here, we show that the outcome of kinetochore phosphorylation depends on tension. Using optogenetics to manipulate Aurora B at individual kinetochores, we find that kinase activity promotes microtubule release when tension is high. Conversely, when tension is low, Aurora B activity promotes depolymerization of kinetochore-microtubules while maintaining attachment. Thus, phosphorylation converts a catch-bond, in which tension stabilizes attachments, to a slip-bond, which releases microtubules under tension. We propose that tension is a signal inducing distinct error-correction pathways, with release or depolymerization being advantageous for typical errors characterized by high or low tension, respectively.


Assuntos
Aurora Quinase B/metabolismo , Cinetocoros/fisiologia , Microtúbulos/fisiologia , Mitose , Tensinas/metabolismo , Aurora Quinase B/genética , Segregação de Cromossomos , Células HeLa , Humanos , Fosforilação
18.
Pest Manag Sci ; 77(9): 3990-3999, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33890699

RESUMO

BACKGROUND: Chilo suppressalis and Cnaphalocrocis medinalis are destructive rice pests co-occurring in major rice-growing areas in China. RNA interference (RNAi)-based insect-resistant genetically engineered (IRGE) crops provide a promising approach for pest management by suppressing gene expression or translation. A microRNA (miRNA)-mediated IRGE rice line expressing endogenous Chilo suppressalis miRNA Csu-novel-260, showing significant resistance against Chilo suppressalis, provides an attractive control strategy for Chilo suppressalis by suppressing the expression of the disembodied (dib) gene expression. However, whether this transgenic line also shows the resistance against Cnaphalocrocis medinalis remains unknown. RESULTS: A spatiotemporal expression analysis of Csu-novel-260 in the transgenic rice line was performed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) to determine the paddy field pest exposure dose. In diet feeding assays, a chemically synthesized Csu-novel-260 agomir at 200 fmol g-1 significantly inhibited Chilo suppressalis pupation. However, larval development, survival and pupal weight were not significantly affected. Additionally, the transgenic line significantly affected Cnaphalocrocis medinalis pupation but not larval survival. The qRT-PCR showed that Csdib and Cmdib expression levels were significantly suppressed when the two pests fed on the transgenic line. Additionally, the transgenic line significantly decreased Cry1C-resistant and Cry1C-susceptible Chilo suppressalis larval survival in detached rice tissue feeding assays, indicating that Cry1C-resistant Chilo suppressalis was not cross-resistant to Csu-novel-260 expressed in miRNA-mediated IRGE rice. CONCLUSION: Our study demonstrated that miRNA-mediated IRGE rice significantly inhibited Chilo suppressalis and Cnaphalocrocis medinalis pupation. The results provide a new viewpoint for the application of RNAi-based plants and the inspiration for environmental risk assessment.


Assuntos
MicroRNAs , Mariposas , Oryza , Animais , Larva/genética , MicroRNAs/genética , Mariposas/genética , Oryza/genética , Plantas Geneticamente Modificadas/genética
19.
Entropy (Basel) ; 23(3)2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33809680

RESUMO

Weak measurements have been under intensive investigation in both experiment and theory. Numerous experiments have indicated that the amplified meter shift is produced by the post-selection, yielding an improved precision compared to conventional methods. However, this amplification effect comes at the cost of a reduced rate of acquiring data, which leads to an increasing uncertainty to determine the level of meter shift. From this point of view, a number of theoretical works have suggested that weak measurements cannot improve the precision, or even damage the metrology information due to the post-selection. In this review, we give a comprehensive analysis of the weak measurements to justify their positive effect on prompting measurement precision. As a further step, we introduce two modified weak measurement protocols to boost the precision beyond the standard quantum limit. Compared to previous works beating the standard quantum limit, these protocols are free of using entangled or squeezed states. The achieved precision outperforms that of the conventional method by two orders of magnitude and attains a practical Heisenberg scaling up to n=106 photons.

20.
J Int Med Res ; 49(4): 300060520985365, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33845640

RESUMO

OBJECTIVE: To investigate the therapeutic effect of implanting a three-piece inflatable penile prosthesis (IPP) combined with the phosphodiesterase-5 inhibitor sildenafil in severe erectile dysfunction (ED) patients. METHODS: This randomized controlled study included 123 ED patients. Sixty-two patients received the IPP implantation and 61 patients received the IPP implantation and the phosphodiesterase-5 inhibitor sildenafil. Erectile function and sexual life quality were evaluated using the five-item International Index of Erectile Function (IIEF) and modified Sexual Life Quality Questionnaire-Quality of Life domain (mSLQQ-QoL), respectively. Serum interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, vascular cell adhesion molecule (VCAM)-1, and intercellular adhesion molecule (ICAM)-1 levels were assessed. Kaplan-Meier curves were used to assess the overall IPP survival. RESULTS: Implantation of the three-piece IPP with sildenafil improved erectile function and sexual life quality, alleviated the inflammatory response, reduced the complication rate, and improved overall IPP survival. CONCLUSION: Implantation of the three-piece IPP combined with a phosphodiesterase-5 inhibitor significantly improved clinical outcomes and the prognosis in ED patients.


Assuntos
Disfunção Erétil , Implante Peniano , Prótese de Pênis , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Disfunção Erétil/tratamento farmacológico , Humanos , Masculino , Satisfação do Paciente , Inibidores da Fosfodiesterase 5/uso terapêutico , Qualidade de Vida
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...