Abstract
Plant heat shock transcription factors (HSFs) are involved in heat and other abiotic stress responses. However, their functions in salt tolerance are little known. In this study, we ...characterized the function of a HSF from Arabidopsis, AtHSFA7b, in salt tolerance. AtHSFA7b is a nuclear protein with transactivation activity. ChIP-seq combined with an RNA-seq assay indicated that AtHSFA7b preferentially binds to a novel cis-acting element, termed the E-box-like motif, to regulate gene expression; it also binds to the heat shock element motif. Under salt conditions, AtHSFA7b regulates its target genes to mediate serial physiological changes, including maintaining cellular ion homeostasis, reducing water loss rate, decreasing reactive oxygen species accumulation, and adjusting osmotic potential, which ultimately leads to improved salt tolerance. Additionally, most cellulose synthase-like (CSL) and cellulose synthase (CESA) family genes were inhibited by AtHSFA7b; some of them were randomly selected for salt tolerance characterization, and they were mainly found to negatively modulate salt tolerance. By contrast, some transcription factors (TFs) were induced by AtHSFA7b; among them, we randomly identified six TFs that positively regulate salt tolerance. Thus, AtHSFA7b serves as a transactivator that positively mediates salinity tolerance mainly through binding to the E-box-like motif to regulate gene expression.
The heat shock transcription factor AtHSFA7b binds to an E-box-like cis-acting element to control ion homeostasis, stomatal aperture, ROS accumulation, osmotic potential, and cellulose biosynthesis, which ultimately mediates salt tolerance.
Lignocellulosic biomass was converted into hierarchical porous carbon by using a physical activation technique under a carbon dioxide environment. Both direct and indirect CO2 activation routes were ...utilized to investigate the effect of processing parameters and the kinetics of the activation. The porosity, surface chemistry, and morphology of the activated carbons were characterized in addition to their proximate and ultimate analyses. This was followed by the preparation of the activated carbon electrodes and the fabrication and electrochemical testing of these electrodes within a symmetrical supercapacitor cell. The results showed a dominant microporous structure along with the limited content of larger pores for the activated carbons prepared via both direct and indirect activation. Along with the preserved natural pore structure of the biomass, an engineered pore structure was achieved which is highly beneficial for the supercapacitors with respect to the transport and storage of ions. The morphological analysis also revealed their tortuous porous structure. The maximum specific capacitances of 80.9 and 92.7 F/g at the current density of 100 mA/g were achieved after direct and indirect activation routes, respectively. The surface functional groups were also found to play a significant role in the resultant electrochemical performance of the supercapacitors.
•Energy crop hybrid willow was converted to activated carbon by direct and indirect CO2 activation.•Optimized activation condition is at temperature of 800 °C and residence time of 60 min.•Activated carbons of indirect route have higher capacitances and better cycling performance.•Surface functional groups and porosity both contribute to the capacitance of activated carbons.
RG-7916 is a first-in-class drug candidate for the treatment of spinal muscular atrophy (SMA) that functions by modulating pre-mRNA splicing of the SMN2 gene, resulting in a 2.5-fold increase in ...survival of motor neuron (SMN) protein level, a key protein lacking in SMA patients. RG-7916 is currently in three interventional phase 2 clinical trials for various types of SMA. In this report, we show that SMN-C2 and -C3, close analogs of RG-7916, act as selective RNA-binding ligands that modulate pre-mRNA splicing. Chemical proteomic and genomic techniques reveal that SMN-C2 directly binds to the AGGAAG motif on exon 7 of the SMN2 pre-mRNA, and promotes a conformational change in two to three unpaired nucleotides at the junction of intron 6 and exon 7 in both in vitro and in-cell models. This change creates a new functional binding surface that increases binding of the splicing modulators, far upstream element binding protein 1 (FUBP1) and its homolog, KH-type splicing regulatory protein (KHSRP), to the SMN-C2/C3–SMN2 pre-mRNA complex and enhances SMN2 splicing. These findings underscore the potential of small-molecule drugs to selectively bind RNA and modulate pre-mRNA splicing as an approach to the treatment of human disease.
•Throughfall reduction interacts with soil warming to affect soil respiration.•Both throughfall reduction and soil warming alone markedly elevate soil respiration.•Throughfall reduction with soil ...warming tends to decrease soil respiration.•Heterotrophic respiration is stimulated by soil warming not by rainfall reduction.
Examining responses of soil respiration to climate change is crucial for understanding future terrestrial carbon (C) cycling. However, the interaction between climate warming and precipitation reduction on soil respiration has not been well documented. This study aimed to determine the impacts of soil warming and throughfall reduction on soil respiration and its components (heterotrophic respiration and autotrophic respiration).
A field manipulation experiment with soil warming and throughfall reduction was conducted in an oak natural forest (Quercus aliena) at a transitional climatic zone in central China during the growing seasons (May–November) in 2011 and 2012. Soil temperature was elevated by 1.23–1.66°C relative to the ambient environment by using infrared heaters, and throughfall was reduced by 50% through roof interception.
There were significant interactive effects of soil warming and throughfall reduction on soil respiration and autotrophic respiration in both 2011 and 2012. Soil warming substantially elevated soil respiration by 32.0–46.3% and autotrophic respiration by 57.8–63.2% without throughfall reduction, respectively, but suppressed both of them with throughfall reduction. Throughfall reduction increased soil respiration by 16.2–37.2% and autotrophic respiration by 62.9–97.7% under ambient temperature, whereas decreased them by 13.7–29.2% and 22.6–51.9% under soil warming. Heterotrophic respiration was significantly increased by soil warming while showed little effect by throughfall reduction or its interactions with soil warming. The offset of the positive warming effect on soil respiration under throughfall reduction may be attributed mainly to the changes in soil microbial biomass and fine root biomass induced by throughfall reduction.
Our observations suggest that either climate warming or precipitation reduction may increase soil CO2 emission, but this stimulation in oak forests will be largely counteracted if climate warming accompanies with simultaneous precipitation reduction at the climatic transitional zone.
Life-cycle assessment (LCA) and techno-economic analysis (TEA) were applied to assess the economic feasibility and environmental benefits of utilizing multiple biomass feedstocks for bioenergy ...products under three different technological pathways with consideration of uncertainties. Three cases were studied for the production of pellets, biomass-based electricity, and pyrolysis bio-oil. A Monte Carlo simulation was used to examine the uncertainties of fossil energy consumption, bioenergy conversion efficiency, stochastic production rate, etc. The cradle-to-gate LCA results showed that pellet production had the lowest greenhouse gas (GHG) emissions, water and fossil fuels consumption (8.29 kg CO2 eq (equivalent), 0.46 kg, and 105.42 MJ, respectively). The conversion process presented a greater environmental impact for all three bioenergy products. When producing 46,929 Mg of pellets, 223,380 MWh of electricity, and 78,000 barrels of pyrolysis oil, the net present values (NPV) indicated that only pellet and electricity production were profitable with NPVs of $1.20 million for pellets, and $5.59 million for biopower. Uncertainty analysis indicated that pellet production showed the highest uncertainty in GHG emission, and bio-oil production had the least uncertainty in GHG emission but had risks producing greater-than-normal amounts of GHG. Biopower production had the highest probability to be a profitable investment with 85.23%.
Abstract
Biodiversity patterns across geographical gradients could result from regional species pool and local community assembly mechanisms. However, little has been done to separate the effects of ...local ecological mechanisms from variation in the regional species pools on bacterial diversity patterns. In this study, we compare assembly mechanisms of soil bacterial communities in 660 plots from 11 regions along a latitudinal gradient in eastern China with highly divergent species pools. Our results show that β diversity does not co-vary with γ diversity, and local community assembly mechanisms appear to explain variation in β diversity patterns after correcting for variation in regional species pools. The variation in environmental conditions along the latitudinal gradient accounts for the variation in β diversity through mediating the strength of heterogeneous selection. In conclusion, our study clearly illustrates the importance of local community assembly processes in shaping geographical patterns of soil bacterial β diversity.
This paper develops a synchronous generator emulator by using a three-phase voltage source converter for transmission level power system testing. Different interface algorithms are compared, and the ...voltage type ideal transformer model is selected considering accuracy and stability. At the same time, closed-loop voltage control with current feed-forward is proposed to decrease the emulation error. The emulation is then verified through two different ways. First, the output waveforms of the emulator in experiments are compared with the simulation under the same condition. Second, a transfer function perturbation-based error model is obtained and redefined as the relative error for the amplitude and phase between the emulated and the target system over the frequency range of interest. The major cause of the error is investigated through a quantitative analysis of the error with varying parameters.
A hardware testbed platform emulating multiple-area power system scenario dynamics has been established aiming at multiple time-scale real-time emulations. In order to mimic real power flow ...situations in the utility system, the load emulators have to behave like real ones in both their static and dynamic characteristics. A constant-impedance, constant-current, and constant-power (ZIP) model has been used for static load types, while a three-phase induction motor model has been built to represent dynamic load types. In this paper, ways of modeling ZIP and induction motor loads and the performance of each load emulator are discussed. Comparisons between simulation and experimental results are shown as well for the validation of the emulator behaviors. A real-time composite power load emulator is then demonstrated with desired characteristics and detailed transients for representing a power system PQ bus dynamics.
Identification of the motifs bound by a transcription factor (TF) is important to reveal the function of TF. Previously, we built a transcription factor centered yeast one hybrid (TF-Centered Y1H) ...that could identify the motifs bound by a target TF. However, that method was difficult to comprehensively identify all the motifs bound by a TF.
Here, we build an improved TF-Centered Y1H to comprehensively determine the motifs bound by a target TF. Recombination-mediated cloning in yeast was performed to construct a saturated prey library that contains 7 random base insertions. After TF-Centered Y1H screening, all the positive clones were pooled together to isolate pHIS2 vector. The insertion regions of pHIS2 were PCR amplified and the PCR product was subjected to high-throughput sequencing. The insertion sequences were then retrieved and analyzed using MEME program to identify the potential motifs bound by the TF. Using this technology, we studied the motifs bound by an ethylene-responsive factor (BpERF2) from birch. In total, 22 conserved motifs were identified, and most of them are novel cis-acting elements. Both the yeast one hybrid and electrophoretic mobility shift assay verified that the obtained motifs could be bound by BpERF2. In addition, chromatin immunoprecipitation (ChIP) study further suggested that the identified motifs can be bound by BpERF2 in cells of birch. These results together suggested that this technology is reliable and has biological significance.
This method will have wide application in DNA-protein interaction studies.
Gene expression profiles are powerful tools for investigating mechanisms of plant stress tolerance.
(birch) is a widely distributed tree, but its drought-tolerance mechanism has been little studied. ...Using RNA-Seq, we identified 2917 birch genes involved in its response to drought stress. These drought-responsive genes include the late embryogenesis abundant (LEA) family, heat shock protein (HSP) family, water shortage-related and ROS-scavenging proteins, and many transcription factors (TFs). Among the drought-induced TFs, the ethylene responsive factor (ERF) and myeloblastosis oncogene (MYB) families were the most abundant. BpERF2 and BpMYB102, which were strongly induced by drought and had high transcription levels, were selected to study their regulatory networks. BpERF2 and BpMYB102 both played roles in enhancing drought tolerance in birch. Chromatin immunoprecipitation combined with qRT-PCR indicated that BpERF2 regulated genes such as those in the
and
families, while BpMYB102 regulated genes such as
(
) and
(
). Multiple genes were regulated by both BpERF2 and BpMYB102. We further characterized the function of some of these genes, and the genes that encode Root Primordium Defective 1 (RPD1), PRP1, 4CL10, LEA1, SOD5, and HSPs were found to be involved in drought tolerance. Therefore, our results suggest that BpERF2 and BpMYB102 serve as transcription factors that regulate a series of drought-tolerance genes in
to improve drought tolerance.
PDF
