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Spontaneous gain or loss of DNA methylation occurs in plant and animal genomes, and DNA methylation changes can lead to meiotically stable epialleles that generate heritable phenotypic diversity. However, it is unclear whether transgenerational epigenetic stability may be regulated by any cellular factors. Here, we examined spontaneously occurring variations in DNA methylation in wild-type and ros1 mutant Arabidopsis plants that were propagated for ten generations from single-seed descent. We found that the ros1 mutant, which is defective in active DNA demethylation, showed an increased transgenerational epimutation rate. The ros1 mutation led to more spontaneously gained methylation than lost methylation at individual cytosines, compared to the wild type which had similar numbers of spontaneously gained and lost methylation cytosines. Consistently, transgenerational differentially methylated regions were also biased toward hypermethylation in the ros1 mutant. Our results reveal a genetic contribution of the ROS1 DNA demethylase to transgenerational epigenetic stability and suggest that ROS1 may have an unexpected surveillance function in preventing transgenerational DNA methylation increases. [ABSTRACT FROM AUTHOR]

Recent studies have shown that corn-derived cationic a-D-glucan nanoparticles, known as Nano-11, significantly increase the immune response when used as a vaccine adjuvant in mice and in pigs. Furthermore, the nanoparticles can be formulated with other immunostimulators such as poly(I:C), which further enhances the immune response. The current experiments were aimed at elucidating the mechanism of action of Nano-11 alone and in combination with poly(I:C). The effect of these adjuvants on porcine monocyte-derived dendritic cells (Mo-DCs) was determined by RNAsequencing, supplemented with flow cytometry, cytokine analysis, and Western blots. Adsorption of poly(I:C) to Nano-11 reduced its cytotoxicity for Mo-DCs. Exposure of Mo-DCs to Nano-11 and Nano-11/poly(I:C) induced differential expression of 979 and 2016 genes, respectively. Gene Ontology enrichment and KEGG pathway analysis revealed many changes in gene expression related to inflammation, innate immunity, immune response to infections, and metabolism. Nano-11 and Nano-11/poly(I:C) induced maturation of the Mo-DCs as indicated by increased expression of costimulatory molecules and MHC II. Increased expression of genes downstream of p38 MAPK activation revealed a role for this signaling pathway in the activation of Mo-DCs by the adjuvants. This was confirmed by Western blot and inhibition of TNF-secretion upon incubation with the p38 inhibitor SB203580. These experiments provide insights into the mechanism of action of the novel adjuvants Nano-11 and Nano-11/poly(I:C). [ABSTRACT FROM AUTHOR]

The objectives of this study were to characterize the meat exudate proteome and metabolome composition that may be related to the color and oxidative stability of beef muscles during aging. Beef longissimus lumborum (LD) and psoas major (PM) muscles from seven carcasses were obtained at 2 d postmortem. Each muscle was cut into three sections, vacuum packaged and assigned into three aging periods (9, 16 and 23 d). At the end of each aging period, the exudate was collected from each sample and immediately frozen for both proteomics and metabolomics analyses. Steak cuts were made for display color and oxidative stability analyses. Exudate samples were prepared and analyzed using the UPLC-ESI-MS for metabolomics profiling and HPLC-MS/MS for proteomics analyses. The metabolites were annotated using the HMDB database, and proteins were compared with the UniProt database. The relative abundance of the metabolites and proteins was quantified and normalized for statistical analysis. Both proteomes and metabolites were analyzed using ANOVA (P < 0.05). Principal component analysis (PCA), hierarchical cluster analysis (HCA) and correlation test between color and lipid oxidative stability and metabolites/proteins were performed. Untargeted protein profiling identified a total of 737 proteins from the meat exudate, of which 222 proteins were affected by the treatments (P < 0.05). PCA analysis indicated an apparent clustering of the proteins, mainly separating the cluster by the muscle types. A greater number of oxidative metabolism enzymes was identified in PM exudate, while more glycolytic metabolism enzymes were identified in LD exudate. Additionally, a greater abundance of cytochrome c was observed in PM muscle exudate along with laminin proteins, indicating a greater extent of degradation in the muscle, potentially explaining the lower oxidative stability of PM muscle. A total of 518 metabolite features was detected from the meat exudate using untargeted metabolomics analysis, in which 167 features were affected by the treatments (P < 0.05). The PCA analysis exhibited a distinct grouping of the treatments, separating not only muscle types but also the aging periods. Greater antioxidant compounds, such as carnitines and glucosides, were identified in LD muscle exudate. A greater number of lipid and nucleotide metabolites were also observed in LD exudate and 23d exudate. HSP70 and laminin proteins, along with glucosides metabolites identified in the exudates, which were significantly correlated (r > 0.5) to muscle color and oxidative stability. The current results indicated that meat exudate could be a viable analytical matrix to understand oxidative stability and protein degradation of muscles during aging. The proteomics and metabolomics profiling identified specific compounds in meat exudate that could be related to different oxidative stability of beef muscles. Further research should be warranted to validate the identified compounds as potential biomarkers to predict oxidative stability and quality attributes of specific muscles during aging. [ABSTRACT FROM AUTHOR]

This study proposes a pre-stage flexible DC–DC converter (PFDDC) for PV micro-inverter. The PFDDC can be operated in different modes automatically, i.e. the improved full-bridge mode when the output power is higher than the threshold value or in the improved two-transistor forward mode when the output power is lower than the threshold value. The operational principles of the PFDDC in different modes are analysed. The design of the key parameters, such as the turns ratio of transformer and buffering inductance, is presented at first. Then the loss analysis of the PFDDC in different modes is used to determine the threshold power, based on which a switch control strategy according to the threshold power value is proposed. Integration of two operational modes in a single PFDDC can effectively increase the weighted efficiency of the PV micro-inverter to easily satisfy the mandatory efficiency requirement in Europe and USA. Experimental results are presented to verify the effectiveness of the proposed PFDDC. [ABSTRACT FROM AUTHOR]

Background: Switchgrass is a crop with many desirable traits for bioenergy production. Plant genomes have high DNA methylation levels throughout genes and transposable elements and DNA methylation is known to play a role in silencing transposable elements. Here we analyzed methylomes in two switchgrass genotypes AP13 and VS16. AP13 is derived from a lowland ecotype and VS16, typically considered drought-tolerant, is derived from an upland ecotype, both genotypes are tetraploid (2n = 4× = 36). Results: Methylated DNA immunoprecipitation-sequencing (MeDIP-seq) and bisulfite-sequencing (BS-seq) were used to profile DNA methylation in genomic features of AP13 and VS16. The methylation patterns in genes and transposable elements were similar to other plants, however, overall CHH methylation levels were comparatively low. Differentially methylated regions (DMRs) were assessed and a total of 1777 CG-DMRs, 573 CHG-DMRs, and 3 CHH-DMRs were detected between the two genotypes. TEs and their flanking regions were higher than that of genic regions. Different types of TEs had different methylation patterns, but the two LTRs (Copia and Gypsy) were similarly methylated, while LINEs and DNA transposons typically had different methylation patterns. MeDIP-seq data was compared to BS-seq data and most of the peaks generated by MeDIP-seq were confirmed to be highly methylated by BS-seq. Conclusions: DNA methylation in switchgrass genotypes obtained from the two ecotypes were found similar. Collinear gene pairs in two subgenomes (A and B) were not significantly differentially methylated. Both BS-seq and MeDIP-seq methodologies were found effective. Methylation levels were highest at CG and least in CHH. Increased DNA methylation was seen in TEs compared to genic regions. Exploitation of TE methylations can be a viable option in future crop improvement. [ABSTRACT FROM AUTHOR]

An LCL-filter draws much attention in grid-connected applications, but the design faces challenges. The LCL and controller parameters are interdependent and inter-restricted as the grid current quality and control stability rely on the parameters of them both. In the past, researchers found that extra sensors or complex algorithms were required for the stability when the LCL parameters were designed independently. Consequently, the system cost and complexity were increased. Indeed, the LCL-filter with the delay-dependent single-loop current control can be stable if the LCL parameters are properly selected. Based on this thought, this study proposes to design the LCL parameters by considering their impact on the stability and dynamic of the inverter. Extra sensors or complex algorithms are no longer required. Based on establishing the model of the single-loop inverter-side current controlled inverter, the criteria of LCL design are obtained in order to improve the stability and the rejections of low-order and switching current harmonics. Based on those design criteria, a step-by-step procedure is proposed. Selected results have been provided to demonstrate the effectiveness of the proposed design. [ABSTRACT FROM AUTHOR]

Flux-switching hybrid excitation machine (FSHM) is an interesting brushless machine with the advantage superiority of field adjustability. In this paper we address the challenges of rising costs and decreasing operational reliability by adding location sensors and employing one-cycle control (OCC) for FSHM generation system. Using field simulation and curve fitting, we establish FSHM model in Matlab/Simulink environment. To meet the requirements of OCC stability, armature current harmonic suppression and dynamic tracking performance, we consider the feasibility of using equivalent inductance as energy-storage inductance of PWM rectifier. The correctness and effectiveness of the proposed method are verified by simulation and experimental results on a 1.5kW prototype generator, which shows PWM rectifier adopting OCC strategy can effectively suppress the armature currents harmonics and keep the output DC voltage constant without position sensor. [ABSTRACT FROM AUTHOR]

Bi-tooth flux-switching permanent magnet (FSPM) machine is an interesting brushless machine having magnets and excitation windings in the stator, which exhibits larger back EMF and requires only half the number and volume of PMs compared to conventional FSPM machine. However, air gap magnetic field is difficult to be regulated due to PM excitation alone. In this paper, by introducing an additional field winding and a bypass iron bridge, a novel hybrid excitation flux-switching machine is proposed, which can easily control the air-gap field. The regulation principle, operational feature and electromagnetism performance such as flux-linkage, back-EMF waveforms, and flux regulation capability with different excitations are evaluated by 2D finite element analysis. [ABSTRACT FROM AUTHOR]

From the perspective of output voltage control stability, this study investigates the stable operating area of photovoltaic (PV) cells feeding the DC-DC converter in output voltage regulation (OVR) mode. In this study, the boost interface converter is taken as an example, and its control system arrangements, small-signal model including the dynamic equivalent circuit of PV cells and the closed-loop transfer functions with different control loop formation are deduced at first. After that, according to the Hurwitz criterion, the essential condition for output voltage control stability is analysed and the relations between control loop formation of the interface converter in OVR mode and the stable operating area are obtained. The validity of the theoretical analysis has been verified by the experiment and simulation results of a 150 W prototype. The investigation shows that: (i) no matter what kind of control loop formation is adopted, the PV cells cannot output the maximum power when the PV interface converter operates in OVR mode; (ii) when the interface converter operates in OVR mode, PV cells can only operate stably in voltage area or current area. Moreover, the type of operating area entirely depends on the converter's output voltage control loop formation. [ABSTRACT FROM AUTHOR]

Although researchers have established that DNA methylation and active demethylation are dynamically regulated in plant cells, the molecular mechanism for the regulation of active DNA demethylation is not well understood. By using an Arabidopsis (Arabidopsis thaliana) line expressing the Promoter RESPONSIVE TO DEHYDRATION 29A:LUCIFERASE (ProRD29A:LUC) and Promoter cauliflower mosaic virus 35S:NEOMYCIN PHOSPHOTRANSFERASE II (Pro35S:NPTII) transgenes, we isolated an mbd7 (for methyl-CpG-binding domain protein7) mutant. The mbd7 mutation causes an inactivation of the Pro35S:NPTII transgene but does not affect the expression of the ProRD29A:LUC transgene. The silencing of the Pro35S:NPTII reporter gene is associated with DNA hypermethylation of the reporter gene. MBD7 interacts physically with REPRESSOR OF SILENCING5/INCREASED DNA METHYLATION2, a protein in the small heat shock protein family. MBD7 prefers to target the genomic loci with high densities of DNA methylation around chromocenters. The Gypsy-type long terminal repeat retrotransposons mainly distributed around chromocenters are most affected by mbd7 in all transposons. Our results suggest that MBD7 is required for active DNA demethylation and antisilencing of the genomic loci with high densities of DNA methylation in Arabidopsis. [ABSTRACT FROM AUTHOR]

With two controllable switches, the efficiency of the two-switch buck-boost converters can be optimised by adopting appropriate control schemes. Among the control schemes, when only one switch works at high frequency, losses of the converter can be reduced effectively, but the complicated control logic and compensation technique are needed for step-up/down smooth transitions; when both switches operate at high frequency, the efficiency of these converters are low for high-voltage applications because of the serious switching losses. In this study, the coupled inductor is introduced to reduce the switching losses of these converters for high-voltage application and an asynchronous control scheme is proposed to reduce the losses much more. Based on the designed prototype, theoretical calculation, experiment results and loss analysis are provided to compare the traditional converter adopting single-winding inductor and the proposed circuit with the coupled inductor. And the comparisons of the converter adopting coupled-inductor with the tradition synchronous control scheme and that with the proposed asynchronous control scheme are also presented. The analysis and experimental results show that the efficiency of the converter adopting coupled inductor with the proposed asynchronous control scheme is the highest one. Moreover, the smooth transitions between step-up and step-down are also guaranteed by the proposed asynchronous control scheme. [ABSTRACT FROM AUTHOR]

In grid-connected LCL-filtered inverters, the dual-loop current control is widely used. The LCL resonance is highly damped by proper feedback of the capacitor current. To suppress low-frequency current harmonics, a grid-voltage feedforward is commonly used. However, the system performance with such control is declined when connecting to a weak grid. Phase and gain margins are largely reduced while the proportional feedforward is used. The margins get worse and instability is aroused if the derivative feedforward is further implemented. Besides, a negative impact on the rejection of gridvoltage- induced harmonics is produced. To improve the control performance in the weak grid case, an adaptive control has been proposed. Adopting the estimated grid impedance, the signal for the grid-voltage feedforward is modified and the controller is adjusted with an adaptive rule to maintain a good phase margin or a high bandwidth. Performances of the inverter with the typical and the proposed methods are compared. Simulation and experimental results have demonstrated that the grid-connected LCL-filtered inverter with the proposed method produced a high-quality current while large grid impedance existed. [ABSTRACT FROM AUTHOR]

Maize (Zea mays) is an excellent cereal model for research on seed development because of its relatively large size for both embryo and endosperm. Despite the importance of seed in agriculture, the genome-wide transcriptome pattern throughout seed development has not been well characterized. Using high-throughput RNA sequencing, we developed a spatiotemporal transcriptome atlas of B73 maize seed development based on 53 samples from fertilization to maturity for embryo, endosperm, and whole seed tissues. A total of 26,105 genes were found to be involved in programming seed development, including 1,614 transcription factors. Global comparisons of gene expression highlighted the fundamental transcriptomic reprogramming and the phases of development. Coexpression analysis provided further insight into the dynamic reprogramming of the transcriptome by revealing functional transitions during maturation. Combined with the published nonseed high-throughput RNA sequencing data, we identified 91 transcription factors and 1,167 other seed-specific genes, which should help elucidate key mechanisms and regulatory networks that underlie seed development. In addition, correlation of gene expression with the pattern of DNA methylation revealed that hypomethylation of the gene body region should be an important factor for the expressional activation of seed-specific genes, especially for extremely highly expressed genes such as zeins. This study provides a valuable resource for understanding the genetic control of seed development of monocotyledon plants. [ABSTRACT FROM AUTHOR]