electric-field-control-electronic-states-ws2-nanodevices-electrolyte

Electric-field Control of Electronic States in WS<sub>2</sub> Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

computer-vision-based-biomass-estimation-for-invasive-plants

Computer Vision-Based Biomass Estimation for Invasive Plants

We report on the detailed steps of a method to estimate the biomass of invasive plants based on UAV remote sensing and computer vision. To collect samples ...

Chinese Academy of Agricultural Sciences

A transcription factor DREB2A functions as a key regulator not only in drought stress responses but also in heat stress (HS) responses, and activates expression of many abiotic stress-responsive-genes involved in drought and HS tolerance. HsfA3 is one of the most up-regulated heat-inducible genes in transgenic plants overexpressing DREB2A. In this study, the analyses of HsfA3 expression profile and the transactivation analysis of HsfA3 showed that the expression of HsfA3 was directly regulated by DREB2A under HS. Microarray analysis using transgenic plants overexpressing HsfA3 also showed that overexpression of HsfA3 induces many heat-inducible genes. Furthermore, we showed that thermotolerance of the HsfA3 overexpressors was increased, and that of the hsfA3 T-DNA tagged mutants was decreased. These results indicate that HsfA3 regulates expression of many heat-inducible genes in the transcriptional cascade downstream of the DREB2A stress-regulatory system and functions in acquisition of thermotolerance under the control of the DREB2A cascade.

Functional analysis of an Arabidopsis heat-shock transcription factor HsfA3 in the transcriptional cascade downstream of the DREB2A stress-regulatory system.

The SPINDLY (SPY) gene was first identified as a negative regulator of plant gibberellic acid (GA) signaling because mutation of this gene phenocopies plants treated with an overdose of bioactive GA and results in insensitivity to a GA inhibitor during seed germination. The SPY gene encodes an O-linked N-acetylglucosamine transferase that can modify the target protein and modulate the protein activity in cells. In this study, we describe the strong salt and drought tolerance phenotypes of Arabidopsis (Arabidopsis thaliana) spy-1 and spy-3 mutants in addition to their GA-related phenotypes. SPY gene expression was found to be drought stress inducible and slightly responsive to salt stress. Transcriptome analysis of spy-3 revealed that many GA-responsive genes were up-regulated, which could explain the GA-overdosed phenotype of spy-3. Some stress-inducible genes were found to be up-regulated in spy-3, such as genes encoding late embryogenesis abundant proteins, Responsive to Dehydration20, and AREB1-like transcription factor, which may confer stress tolerance on spy-3. CKX3, a cytokinin (CK) catabolism gene, was up-regulated in spy-3; this up-regulation indicates that the mutant possesses reduced CK signaling, which is consistent with a positive role for SPY in CK signaling. Moreover, overexpression of SPY in transgenics (SPY overexpressing [SPY-OX]) impaired plant drought stress tolerance, opposite to the phenotype of spy. The expression levels of several genes, such as DREB1E/DDF1 and SNH1/WIN1, were decreased in SPY-OX but increased in spy-3. Taken together, these data indicate that SPY plays a negative role in plant abiotic stress tolerance, probably by integrating environmental stress signals via GA and CK cross talk.

SPINDLY, a negative regulator of gibberellic acid signaling, is involved in the plant abiotic stress response.

The worldwide production of maize (Zea mays L.) is frequently impacted by water scarcity and as a result, increased drought tolerance is a priority target in maize breeding programs. While DREB transcription factors have been demonstrated to play a central role in desiccation tolerance, whether or not natural sequence variations in these genes are associated with the phenotypic variability of this trait is largely unknown. In the present study, eighteen ZmDREB genes present in the maize B73 genome were cloned and systematically analyzed to determine their phylogenetic relationship, synteny with rice, maize and sorghum genomes; pattern of drought-responsive gene expression, and protein transactivation activity. Importantly, the association between the nucleic acid variation of each ZmDREB gene with drought tolerance was evaluated using a diverse population of maize consisting of 368 varieties from tropical and temperate regions. A significant association between the genetic variation of ZmDREB2.7 and drought tolerance at seedling stage was identified. Further analysis found that the DNA polymorphisms in the promoter region of ZmDREB2.7, but not the protein coding region itself, was associated with different levels of drought tolerance among maize varieties, likely due to distinct patterns of gene expression in response to drought stress. In vitro, protein-DNA binding assay demonstrated that ZmDREB2.7 protein could specifically interact with the target DNA sequences. The transgenic Arabidopsis overexpressing ZmDREB2.7 displayed enhanced tolerance to drought stress. Moreover, a favorable allele of ZmDREB2.7, identified in the drought-tolerant maize varieties, was effective in imparting plant tolerance to drought stress. Based upon these findings, we conclude that natural variation in the promoter of ZmDREB2.7 contributes to maize drought tolerance, and that the gene and its favorable allele may be an important genetic resource for the genetic improvement of drought tolerance in maize.

Genome-wide analysis of ZmDREB genes and their association with natural variation in drought tolerance at seedling stage of Zea mays L.

The Arabidopsis thaliana transcription factor DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN2A (DREB2A) controls the expression of many genes involved in the plant's response to dehydration and heat stress. Despite the significance of post-translational regulation in DREB2A activation, the mechanism underlying this activation remains unclear. Here, with the aid of a newly produced antibody against DREB2A, we characterized the regulation of DREB2A stability in plants exposed to stress stimuli. Endogenous DREB2A accumulated in wild-type Arabidopsis plants subjected to dehydration and heat stress. A degradation assay using Arabidopsis T87 suspension-cultured cells revealed that DREB2A protein degradation was inhibited at high temperatures. The proteasome-dependent degradation of DREB2A required the import of this protein into the nucleus. The E3 ligases DRIP1 and DRIP2 were involved in this process under both normal and stressful conditions; however, other E3 ligases may have also been involved, at least during the late stages of the heat stress response. Although the constitutive expression of DREB2A resulted in an overproduction of DREB2A and enhanced target gene induction during stress in transgenic plants, the accumulation of DREB2A caused by proteasome inhibitors did not induce target gene expression. Thus, the stabilization of DREB2A is important but not sufficient to induce target gene expression; further activation processes are required.

Stabilization of Arabidopsis DREB2A is required but not sufficient for the induction of target genes under conditions of stress.

Drought is one of the most challenging agricultural issues limiting sustainable sugarcane production and, in some cases, yield losses caused by drought are nearly 50%. DREB proteins play vital regulatory roles in abiotic stress responses in plants. The transcription factor DREB2A interacts with a cis-acting DRE sequence to activate the expression of downstream genes that are involved in drought-, salt- and heat-stress response in Arabidopsis thaliana. In the present study, we evaluated the effects of stress-inducible over-expression of AtDREB2A CA on gene expression, leaf water potential (ΨL), relative water content (RWC), sucrose content and gas exchanges of sugarcane plants submitted to a four-days water deficit treatment in a rhizotron-grown root system. The plants were also phenotyped by scanning the roots and measuring morphological parameters of the shoot. The stress-inducible expression of AtDREB2A CA in transgenic sugarcane led to the up-regulation of genes involved in plant response to drought stress. The transgenic plants maintained higher RWC and ΨL over 4 days after withholding water and had higher photosynthetic rates until the 3rd day of water-deficit. Induced expression of AtDREB2A CA in sugarcane increased sucrose levels and improved bud sprouting of the transgenic plants. Our results indicate that induced expression of AtDREB2A CA in sugarcane enhanced its drought tolerance without biomass penalty.

Induced over-expression of AtDREB2A CA improves drought tolerance in sugarcane.

The androgen receptor (AR) is a key driver of prostate cancer (PC), even in the state of castration-resistant PC (CRPC) and frequently even after treatment with second-line hormonal therapies such as abiraterone and enzalutamide. The persistence of AR activity via both ligand-dependent and ligand-independent mechanisms (including constitutively active AR splice variants) highlights the unmet need for alternative approaches to block AR signaling in CRPC. We investigated the transcription factor GATA-binding protein 2 (GATA2) as a regulator of AR signaling and an actionable therapeutic target in PC. We demonstrate that GATA2 directly promotes expression of both full-length and splice-variant AR, resulting in a strong positive correlation between GATA2 and AR expression in both PC cell lines and patient specimens. Conversely, GATA2 expression is repressed by androgen and AR, suggesting a negative feedback regulatory loop that, upon androgen deprivation, derepresses GATA2 to contribute to AR overexpression in CRPC. Simultaneously, GATA2 is necessary for optimal transcriptional activity of both full-length and splice-variant AR. GATA2 colocalizes with AR and Forkhead box protein A1 on chromatin to enhance recruitment of steroid receptor coactivators and formation of the transcriptional holocomplex. In agreement with these important functions, high GATA2 expression and transcriptional activity predicted worse clinical outcome in PC patients. A GATA2 small molecule inhibitor suppressed the expression and transcriptional function of both full-length and splice-variant AR and exerted potent anticancer activity against PC cell lines. We propose pharmacological inhibition of GATA2 as a first-in-field approach to target AR expression and function and improve outcomes in CRPC.

GATA2 facilitates steroid receptor coactivator recruitment to the androgen receptor complex.

DEHYDRATION-RESPONSIVE ELEMENT BINDING PROTEIN 2A (DREB2A) acts as a key transcription factor in both drought and heat stress tolerance inand induces the expression of many drought- and heat stress-inducible genes. Althoughexpression itself is induced by stress, the posttranslational regulation of DREB2A, including protein stabilization, is required for its transcriptional activity. The deletion of a 30-aa central region of DREB2A known as the negative regulatory domain (NRD) transforms DREB2A into a stable and constitutively active form referred to as DREB2A CA. However, the molecular basis of this stabilization and activation has remained unknown for a decade. Here we identified BTB/POZ AND MATH DOMAIN proteins (BPMs), substrate adaptors of the Cullin3 (CUL3)-based E3 ligase, as DREB2A-interacting proteins. We observed that DREB2A and BPMs interact in the nuclei, and that the NRD of DREB2A is sufficient for its interaction with BPMs.-knockdown plants exhibited increased DREB2A accumulation and induction of DREB2A target genes under heat and drought stress conditions. Genetic analysis indicated that the depletion ofexpression conferred enhanced thermotolerance via DREB2A stabilization. Thus, the BPM-CUL3 E3 ligase is likely the long-sought factor responsible for NRD-dependent DREB2A degradation. Through the negative regulation of DREB2A stability, BPMs modulate the heat stress response and prevent an adverse effect of excess DREB2A on plant growth. Furthermore, we found the BPM recognition motif in various transcription factors, implying a general contribution of BPM-mediated proteolysis to divergent cellular responses via an accelerated turnover of transcription factors.

BPM-CUL3 E3 ligase modulates thermotolerance by facilitating negative regulatory domain-mediated degradation of DREB2A in.

Dielectric capacitors with high energy storage density (W) and efficiency (η) are in great demand for high/pulsed power electronic systems, but the state-of-the-art lead-free dielectric materials are facing the challenge of increasing one parameter at the cost of the other. Herein, we report that high W of 6.3 J cm with η of 90% can be simultaneously achieved by constructing a room temperature M2-M3 phase boundary in (1-x)AgNbO-xAgTaO solid solution system. The designed material exhibits high energy storage stability over a wide temperature range of 20-150 °C and excellent cycling reliability up to 10 cycles. All these merits achieved in the studied solid solution are attributed to the unique relaxor antiferroelectric features relevant to the local structure heterogeneity and antiferroelectric ordering, being confirmed by scanning transmission electron microscopy and synchrotron X-ray diffraction. This work provides a good paradigm for developing new lead-free dielectrics for high-power energy storage applications.

Constructing phase boundary in AgNbO antiferroelectrics: pathway simultaneously achieving high energy density and efficiency.

Nanobubbles have many potential applications depending on their types. The long-term stability of different gas nanobubbles is necessary to be studied considering their applications. In the present study, five kinds of nanobubbles (N, O, Ar + 8%H, air and CO) in deionized water and a salt aqueous solution were prepared by the hydrodynamic cavitation method. The mean size and zeta potential of the nanobubbles were measured by a light scattering system, while the pH and Eh of the nanobubble suspensions were measured as a function of time. The nanobubble stability was predicted and discussed by the total potential energies between two bubbles by the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The nanobubbles, except CO, in deionized water showed a long-term stability for 60 days, while they were not stable in the 1 mM (milli mol/L) salt aqueous solution. During the 60 days, the bubble size gradually increased and decreased in deionized water. This size change was discussed by the Ostwald ripening effect coupled with the bubble interaction evaluated by the extended DLVO theory. On the other hand, CO nanobubbles in deionized water were not stable and disappeared after 5 days, while the CO nanobubbles in 1 mM of NaCl and CaCl aqueous solution became stable for 2 weeks. The floating and disappearing phenomena of nanobubbles were estimated and discussed by calculating the relationship between the terminal velocity of the floating bubble and bubble size.

Long-Term Stability of Different Kinds of Gas Nanobubbles in Deionized and Salt Water.

Environmentally friendly lead-free dielectric ceramics have attracted wide attention because of their outstanding power density, rapid charge/dischargerate, and superior stability. Nevertheless, as a hot material in dielectric ceramic capacitors, the energy storage performance of NaBiTiO-based ceramics has been not satisfactory because of their higher remnant polarization value and low dielectric breakdown strength, which is a problem that must be urgently overcome. In this work, the (1 - ) (0.6NaBiTiO - 0.4SrBiTiO) - Ba(MgTa)O (BNST-BMT) systems were designed based on a dual optimization strategy of domain and bandgap to solve the above problems. As a result, a record-breaking ultrahigh energy density and excellent efficiency ( = 8.58 J/cm, η = 93.5%) were obtained simultaneously under 565 kV/cm for the BNST-0.08BMT ceramic. The introduction of SrBiTiO induces the formation of nanodomains in BNT-based ceramics, leading to slim - curves, and the further modification of Mg/Ta reduces the grain sizes and increases the bandgap width, resulting in significant enhancement of the dielectric breakdown strength. Moreover, excellent stability and superior discharge performance ( = 4.7 J/cm,  = 320 kV/cm) in the BNST-0.08BMT ceramic were also achieved. The results suggest that the BNST-0.08BMT ceramic shows potential applicability for dielectric energy storage ceramics. Simultaneously, the composition-design concept in the system provides a good reference for the further development of ceramic dielectric capacitors.

Ultrahigh Energy Storage Density and Efficiency in BiNaTiO-Based Ceramics via the Domain and Bandgap Engineering.

As an efficient and economical way of dealing with organic pollutants, piezo-photocatalysis has attracted great interest. In this work, we demonstrated that ferroelectricity and Schottky heterojunction engineering could significantly enhance the piezo-photocatalytic activity of AgNbO. The poled 20 mol % K doped AgNbO disclosed its superior piezo-photocatalytic activity of 0.131 min for 10 mgL RhB, which is 7.8 times of the pristine one under the condition of illumination only. The designed piezo-photocatalyst also exhibited good piezo-photocatalytic stability after four cycles. These merits are attributed to the built-in electric field associated with the large spontaneous polarization and low coercive field originated from the stable ferroelectric state after ferroelectricity engineering, plus with the electron trapper effect of the in situ precipitated metal Ag particles. Our work not only provides a promising piezo-photocatalyst for degrading organic contaminants but also paves a good way for developing high piezo-photocatalytic activity catalysts.

Ferroelectricity and Schottky Heterojunction Engineering in AgNbO: A Simultaneous Way of Boosting Piezo-photocatalytic Activity.

Five pairs of new racemic alkamides (1a/1b and 4a/4b-7a/7b) and two new achiral derivatives (2-3), as well as five known ones (8-12), were purified from the 95% EtOH extract of Zanthoxylum nitidum. Their structures were elucidated based on spectroscopic analyses (NMR and HR-ESI-MS), electronic circular dichroism (ECD) and NMR calculations. The enantiomeric separation was successfully achieved by chiral-phase HPLC-ECD measurements. Among all the isolates, compounds 2, 3, and 10 showed inhibitory effects against five human cancer cell lines, with IC values in range of 18.51-48.03 μM.

Structurally diverse isobutylamides from Zanthoxylum nitidum.

Antiferroelectrics (AFEs) are promising candidates in energy-storage capacitors, electrocaloric solid-cooling, and displacement transducers. As an actively studied lead-free antiferroelectric (AFE) material, NaNbO has long suffered from its ferroelectric (FE)-like polarization-electric field (P-E) hysteresis loops with high remnant polarization and large hysteresis. Guided by theoretical calculations, a new strategy of reducing the oxygen octahedral tilting angle is proposed to stabilize the AFE P phase (Space group Pbma) of NaNbO. To validate this, we judiciously introduced CaHfO with a low Goldschmidt tolerance factor and AgNbO with a low electronegativity difference into NaNbO, the decreased cation displacements and [BO] octahedral tilting angles were confirmed by Synchrotron X-ray powder diffraction and aberration-corrected scanning transmission electron microscopy. Of particular importance is that the 0.75NaNbO-0.20AgNbO-0.05CaHfO ceramic exhibits highly reversible phase transition between the AFE and FE states, showing well-defined double P-E loops and sprout-shaped strain-electric field curves with reduced hysteresis, low remnant polarization, high AFE-FE phase transition field, and zero negative strain. Our work provides a new strategy for designing NaNbO-based AFE material with well-defined double P-E loops, which can also be extended to discover a variety of new lead-free AFEs.

ArticleTotal : 2	Year
Publication title Cited by 2	2018
Publication title Cited by 1	2024

Article	Year
Functional analysis of an Arabidopsis heat-shock transcription factor HsfA3 in the transcriptional cascade downstream of the DREB2A stress-regulatory system. Biochemical and biophysical research communications\| PubMed ID: 18261981	2008
SPINDLY, a negative regulator of gibberellic acid signaling, is involved in the plant abiotic stress response. Plant physiology\| PubMed ID: 22013217	2011
Genome-wide analysis of ZmDREB genes and their association with natural variation in drought tolerance at seedling stage of Zea mays L. PLoS genetics\| PubMed ID: 24086146	2013
Stabilization of Arabidopsis DREB2A is required but not sufficient for the induction of target genes under conditions of stress. PloS one\| PubMed ID: 24376497	2013
Induced over-expression of AtDREB2A CA improves drought tolerance in sugarcane. Plant science : an international journal of experimental plant biology\| PubMed ID: 24656336	2014
GATA2 facilitates steroid receptor coactivator recruitment to the androgen receptor complex. Proceedings of the National Academy of Sciences of the United States of America\| PubMed ID: 25489091	2014
BPM-CUL3 E3 ligase modulates thermotolerance by facilitating negative regulatory domain-mediated degradation of DREB2A in. Proceedings of the National Academy of Sciences of the United States of America\| PubMed ID: 28923951	2017
Constructing phase boundary in AgNbO antiferroelectrics: pathway simultaneously achieving high energy density and efficiency. Nature communications\| PubMed ID: 32973146	2020
Long-Term Stability of Different Kinds of Gas Nanobubbles in Deionized and Salt Water. Materials (Basel, Switzerland)\| PubMed ID: 33917489	2021
Ultrahigh Energy Storage Density and Efficiency in BiNaTiO-Based Ceramics via the Domain and Bandgap Engineering. ACS applied materials & interfaces\| PubMed ID: 34672188	2021
Ferroelectricity and Schottky Heterojunction Engineering in AgNbO: A Simultaneous Way of Boosting Piezo-photocatalytic Activity. ACS applied materials & interfaces\| PubMed ID: 35503741	2022
Structurally diverse isobutylamides from Zanthoxylum nitidum. Fitoterapia\| PubMed ID: 36496049	2023
Well-defined double hysteresis loop in NaNbO antiferroelectrics. Nature communications\| PubMed ID: 36997552	2023

Feng Qin

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