Once protein-coding, the X-inactivation center (
Xic) is now dominated by large noncoding RNAs (ncRNA). X chromosome inactivation (XCI) equalizes gene expression between mammalian males and females ...by inactivating one X in female cells. XCI requires Xist, an ncRNA that coats the X and recruits Polycomb proteins. How
Xist is controlled remains unclear but likely involves negative and positive regulators. For the active X, the antisense Tsix RNA is an established
Xist repressor. For the inactive X, here, we identify
Xic-encoded
Jpx as an
Xist activator.
Jpx is developmentally regulated and accumulates during XCI. Deleting
Jpx blocks XCI and is female lethal. Posttranscriptional Jpx knockdown recapitulates the knockout, and supplying Jpx in
trans rescues lethality. Thus,
Jpx is
trans-acting and functions as ncRNA. Furthermore,
ΔJpx is rescued by truncating Tsix, indicating an antagonistic relationship between the ncRNAs. We conclude that
Xist is controlled by two RNA-based switches: Tsix for Xa and Jpx for Xi.
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► X chromosome inactivation is controlled by two RNA-based switches, Jpx and Tsix ► Jpx is a long ncRNA that activates Xist expression ► Tsix RNA opposes the action of Jpx RNA ► Unlike other RNAs of the X-inactivation center, Jpx is diffusible and
trans-acting
Organic crystals which can confine and guide optical waves on command are currently of considerable interest because of their tremendous potentials in broadband communications, optoelectronic ...devices, high‐capacity information storage, etc. Polycyclic arenes, with tunable molecular structures, packing modes, and photophysical properties, are a highly versatile class of organic materials, applicable as optical waveguide crystals. In this review, the optical waveguides of polycyclic arene‐based crystals are discussed, focusing on the molecular design, packing structures, crystal engineering, and the corresponding photonic properties. Moreover, several proof‐of‐concept devices are also shown. This review summarizes the current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of optical waveguiding materials.
The fast advances in both polycyclic arenes chemistry and their crystal engineering have greatly promoted the development of crystal photonic materials. In this review, a survey of the contribution of polycyclic arenes on crystal optical waveguides is summarized; several proof‐of‐concept devices are shown, and some of the most prospective future directions are highlighted.
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•MNOP-H2S is highly sensitive to sense H2S with a detection limit of 29 nM.•MNOP-H2S can monitor mitochondrial basal H2S levels.•MNOP-H2S is applied for distinguishing cancer cells ...from normal cells.•MNOP-H2S is applied to verify role of H2S in endothelial cell migration.
Hydrogen sulfide (H2S) is recognized as a critical gaseous signaling molecule involved in multiple physiological and pathological processes. The important pathophysiological roles of H2S have spurred intense interest in developing fluorescent probes for imaging of H2S. Using a piperazidine-bridged styrylpyridinium as the push-pull fluorophore and a 7-nitro-1,2,3-benzoxadiazole moiety as the response group, herein we developed a mitochondria-targeted fluorescent probe MNOP-H2S, which exhibited remarkable fluorescence turn-on (>130 fold), large Stokes shift (190 nm), excellent sensitivity and selectivity. Importantly, the probe was characterized by an ultralow detection limit (29 nM), thereby being successfully applied to monitor mitochondrial basal H2S levels in various types of cells and zebrafish, to distinguish cancer cells from normal cells (even from each other) and to reveal that the endogenously produced H2S in mitochondria is a key mediator for the endothelial cell migration stimulated by vascular endothelial growth factor.
The outbreak of COVID-19 has become a worldwide pandemic. The pathogenesis of this infectious disease and how it differs from other drivers of pneumonia is unclear. Here we analyze urine samples from ...COVID-19 infection cases, healthy donors and non-COVID-19 pneumonia cases using quantitative proteomics. The molecular changes suggest that immunosuppression and tight junction impairment occur in the early stage of COVID-19 infection. Further subgrouping of COVID-19 patients into moderate and severe types shows that an activated immune response emerges in severely affected patients. We propose a two-stage mechanism of pathogenesis for this unusual viral infection. Our data advance our understanding of the clinical features of COVID-19 infections and provide a resource for future mechanistic and therapeutics studies.
Metal-organic frameworks on electrospun modified nanofibers and N-doped carbon nanotubes are constructed for an high-performance asymmetric supercapacitor.
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Metal-organic framework ...(MOF)-based electrode materials have become a hot subject for supercapaitors. Herein, Ni-MOFs grown on Co nanoparticles modified carbon nanofibers (CNFs) (C-Co@MOF) are prepared via a facile process. Interestingly, the presence of Co nanoparticles in CNFs not only boosts the hybridization of CNF and MOFs, but also releases Co ions to participate in the growth of MOF, leading to a favorable electrochemical behavior. In detail, the specific capacitance of C-Co@MOF reaches 1201.6 F g−1 that exceeds those of C-M@MOFs (M = Ni, V, Mo, Mn, Fe, Cu and Zn) and CNF@MOF. More importantly, an asymmetric solid-state supercapacitor is assembled using C-Co@MOF and nitrogen-doped carbon nanotubes derived from polyaniline as positive and negative electrode materials, respectively, representing a high energy density of 37.0 Wh kg−1 and outstanding durability. This work highlights the superiority of electrospun CNFs modified by metal nanoparticles for the growth of MOF, showing great potential for electrochemical energy storage and conversion applications.
Pollutant washoff from road-deposited sediment (RDS) is an increasing problem associated with the rapid urbanization of China that results in urban non-point source pollution. Here, we analyzed the ...RDS grain size distribution and its potential impact on heavy metal pollution in urban runoff from impervious surfaces of urban villages, colleges and residences, and main traffic roads in the Haidian District, Beijing, China. RDS with smaller grain size had a higher metal concentration. Specifically, particles with the smallest grain size (<44
μm) had the highest metal concentration in most areas (unit: mg/kg): Cd 0.28–1.31, Cr 57.9–154, Cu 68.1–142, Ni 25.8–78.0, Pb 73.1–222 and Zn 264–664. Particles with smaller grain size (<250
μm) contributed more than 80% of the total metal loads in RDS washoff, while suspended solids with a grain size <44
μm in runoff water accounted for greater than 70% of the metal mass in the total suspended solids (TSS). The heavy metal content in the TSS was 2.21–6.52% of that in the RDS. These findings will facilitate our understanding of the importance of RDS grain size distribution in heavy metal pollution caused by urban storm runoff.
Recent research suggests that SARS-CoV-2-infected individuals can be highly infectious while asymptomatic or pre-symptomatic, and that an infected person may infect 5.6 other individuals on average. ...This situation highlights the need for rapid, sensitive SARS-CoV-2 diagnostic assays capable of high-throughput operation that can preferably utilize existing equipment to facilitate broad, large-scale screening efforts. We have developed a CRISPR-based assay that can meet all these criteria. This assay utilizes a custom CRISPR Cas12a/gRNA complex and a fluorescent probe to detect target amplicons produced by standard RT-PCR or isothermal recombinase polymerase amplification (RPA), to allow sensitive detection at sites not equipped with real-time PCR systems required for qPCR diagnostics. We found this approach allowed sensitive and robust detection of SARS-CoV-2 positive samples, with a sample-to-answer time of ~50 min, and a limit of detection of 2 copies per sample. CRISPR assay diagnostic results obtained nasal swab samples of individuals with suspected COVID-19 cases were comparable to paired results from a CDC-approved quantitative RT-PCR (RT-qPCR) assay performed in a state testing lab, and superior to those produced by same assay in a clinical lab, where the RT-qPCR assay exhibited multiple invalid or inconclusive results. Our assay also demonstrated greater analytical sensitivity and more robust diagnostic performance than other recently reported CRISPR-based assays. Based on these findings, we believe that a CRISPR-based fluorescent application has potential to improve current COVID-19 screening efforts.
•Integrated CRISPR for COVID-19 clinical diagnosis.•Rapidly identify SARS-CoV-2-specific RNA signatures at an ultra-low concentration.•Detection environment friendly and compatible for high throughput COVID-19 screening in hospital.•Successful development and validation with swab samples from patients.•Improve diagnosis of individuals with suspected COVID-19 infections.
Climate changes in future 21 st century China and their uncertainties are evaluated based on 22 climate models from the Coupled Model Intercomparison Project Phase 5（CMIP5）. By 2081–2100, the annual ...mean surface air temperature（SAT） is predicted to increase by 1.3℃± 0.7℃, 2.6℃± 0.8℃ and 5.2℃± 1.2℃ under the Representative Concentration Pathway（RCP） scenarios RCP2.6, RCP4.5 and RCP8.5, relative to 1986–2005, respectively. The future change in SAT averaged over China increases the most in autumn/winter and the least in spring, while the uncertainty shows little seasonal variation.Spatially, the annual and seasonal mean SAT both show a homogeneous warming pattern across China, with a warming rate increasing from southeastern China to the Tibetan Plateau and northern China, invariant with time and emissions scenario.The associated uncertainty in SAT decreases from northern to southern China. Meanwhile, by 2081–2100, the annual mean precipitation increases by 5% ± 5%, 8% ± 6% and 12% ± 8% under RCP2.6, RCP4.5 and RCP8.5, respectively. The national average precipitation anomaly percentage, largest in spring and smallest in winter, and its uncertainty, largest in winter and smallest in autumn, show visible seasonal variations. Although at a low confidence level, a homogeneous wetting pattern is projected across China on the annual mean scale, with a larger increasing percentage in northern China and a weak drying in southern China in the early 21 st century. The associated uncertainty is also generally larger in northern China and smaller in southwestern China. In addition, both SAT and precipitation usually show larger seasonal variability on the sub-regional scale compared with the national average.
Abstract
Understanding contributions of climate and management intensifications to crop yield trends is essential to better adapt to climate changes and gauge future food security. Here we quantified ...the synergistic contributions of climate and management intensifications to maize yield trends from 1961 to 2017 in Iowa (United States) using a process-based modeling approach with a detailed climatic and agronomic observation database. We found that climate (management intensifications) contributes to approximately 10% (90%), 26% (74%), and 31% (69%) of the yield trends during 1961–2017, 1984–2013, and 1982–1998, respectively. However, the climate contributions show substantial decadal or multi-decadal variations, with the maximum decadal yield trends induced by temperature or radiation changes close to management intensifications induced trends while considerably larger than precipitation induced trends. Management intensifications can produce more yield gains with increased precipitation but greater losses of yields with increased temperature, with extreme drought conditions diminishing the yield gains, while radiation changes have little effect on yield gains from management intensifications. Under the management condition of recent years, the average trend at the higher warming level was about twice lower than that at the lower warming level, and the sensitivity of yield to warming temperature increased with management intensifications from 1961 to 2017. Due to such synergistic effects, management intensifications must account for global warming and incorporate climate adaptation strategies to secure future crop productions. Additional research is needed to understand how plausible adaptation strategies can mitigate synergistic effects from climate and management intensifications.
Drought is one of the abiotic stresses controlling plant function and ecological stability. In the context of climate change, drought is predicted to occur more frequently in the future. Despite ...numerous attempts to clarify the overall effects of drought stress on the growth and physiological processes of plants, a comprehensive evaluation on the impacts of drought stress on biomass allocation, especially on reproductive tissues, remains elusive. We conducted a meta‐analysis by synthesizing 164 published studies to elucidate patterns of plant biomass allocation in relation to drought stress. Results showed that drought significantly increased the fraction of root mass but decreased that of stem, leaf, and reproductive mass. Roots of herbaceous plants were more sensitive to drought than woody plants that reduced reproductive allocation more sharply than the former. Relative to herbaceous plants, drought had a more negative impact on leaf mass fraction of woody plants. Among the herbaceous plants, roots of annuals responded to drought stress more strongly than perennial herbs, but their reproductive allocation was less sensitive to drought than the perennial herbs. In addition, cultivated and wild plants seemed to respond to drought stress in a similar way. Drought stress did not change the scaling exponents of the allometric relationship between different plant tissues. These findings suggest that the allometric partitioning theory, rather than the optimal partitioning theory, better explains the drought‐induced changes in biomass allocation strategies.
Drought significantly increased the fraction of root mass but decreased the mass fractions of stem, leaf, and reproductive parts. Roots of herbaceous plants are more sensitive to drought than woody plants that reduced reproductive allocation more sharply than the former. Drought stress did not alter the scaling exponents of the allometric relationship between different plant tissues.
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