As a subgroup of horticultural crops, vegetable food is a kind of indispensable energy source for human beings, providing necessary nutritional components including vitamins, carbohydrates, dietary ...fiber, and active substances such as carotenoids and flavonoids. The developmental process of vegetable crops is not only regulated by environmental stimulations, but also manipulated by both genetic and epigenetic modifications. Epigenetic modifications are composed by several regulatory mechanisms, including DNA methylation, histone modification, chromatin remodeling, and non-coding RNAs. Among these modifications, DNA methylation functions in multiple biological pathways ranging from fundamental development to environmental stimulations by mediating transcriptomic alterations, resulting in the activation or silencing of target genes. In recent years, intensive studies have revealed that DNA methylation is essential to fruit development and ripening, indicating that the epigenome of fruit crops could be dynamically modified according to the specific requirements in the commercial production. Firstly, this review will present the mechanisms of DNA methylation, and update the understanding on active DNA demethylation in Arabidopsis thaliana. Secondly, this review will summarize the recent progress on the function of DNA methylation in regulating fruit ripening. Moreover, the possible functions of DNA methylation on controlling the expansion of edible organs, senescence of leafy vegetables, and anthocyanin pigmentation in several important vegetable crops will be discussed. Finally, this review will highlight the intractable issues that need to be resolved in the application of epigenome in vegetable crops, and provide perspectives for the potential challenges in the further studies.
•Chemical compositions in fruit of three mulberry species from the same area were analysed.•The black mulberry fruit has the highest levels of organic acids, vitamin C, Fe, flavonoids and ...anthocyanins.•The white mulberry fruit has the highest contents of two essential fatty acids (linoleic acid and α-linolenic acid).
Mulberries are a widely cultivated foodstuff both in China and worldwide. However, there are stark differences in the nutritional values of mulberry species. To better appreciate these differences, we here describe the chemical characteristics of white (Morus alba L.), Russian (M. alba var. tatarica L.), and black (Morus nigra L.) mulberry fruits cultivated in the Xinjiang province of China. The chemical composition analysis was performed by official methods procedures. The amino acids were analysed by the phenyl isothiocyanate method. The 2,6-dichloroindophenol titrimetric method, the aluminium chloride colorimetric method, and the pH differential method were also used in measuring the content of reduced ascorbic acid, total flavonoids, and total monomeric anthocyanins, respectively. The black mulberry fruits had the highest content of reduced ascorbic acid (48.4mg/100gfw), titratable acidity (47.1mg/gfw), and Fe (11.9mg/100gfw) of these 3 species. The Russian mulberry fruits had the highest EAA/TAA (essential amino acid/total amino acid) ratio at 44% followed by the white mulberry (42%) and the black mulberry (29%). The black mulberry fruits had found to be richest in terms of total flavonoids and total monomeric anthocyanins. These results are helpful for selecting mulberry species with abundant nutrients and phytochemicals for commercial cultivation.
Dust pollution in fully mechanized working faces of rock tunnels seriously threatens the safe operation and workers’ health. In order to effectively control the dust and improve the working ...environment in the working face, we simulated the effect of dust suction position, ds and the exhaust air rate, Qs on dust diffusion at the working face by the CFD method. The accuracy and reliability of the numerical simulation were verified by field measurements. It was shown that when ds was 0, 1/4, 1/2, and 3/4, the overall airflow in the tunnel was in a disordered state. The dust, carried by the airflow, was eventually spread to the whole tunnel. When ds was 1, an effective dust control wind curtain with the airflow direction pointing to the working face was achieved under the joint action of exhaust air and pressing air. A uniform flow covering the full section of the tunnel was formed within the range of 4.2–6.5m from the working face. The dust was controlled in an enclosed space between the roadheader and the working face. When Qs was 330–500 m3/min, an effective dust control wind curtain was always formed in front of the roadheader. Consequently, the recommended air exhaust rate under the minimum energy consumption was 330 m3/min.
•Effective numerical analysis model was established.•The migration law of airflow-dust with different dust suction parameters was obtained.•The dust suction parameters with optimal dust control effect were obtained.•The dust suction parameters with optimal energy conservation were obtained.
To investigate the seismic response of a bedding rock slope, a time-frequency joint analysis method was proposed using the finite element method (FEM) based on the time, frequency, and time-frequency ...domains. According to the time-frequency joint analysis, the results show that the topographic and geological conditions have great impacts on the dynamic response characteristics of the slope. An obvious slope surface and elevation amplification effect can be observed during earthquake excitation. The bedding structural plane has a great influence on the characteristics of wave propagation through the slope. The impacts of the structural plane and wave propagation directions on the seismic response of the slope are discussed. In addition, dynamic deformation characteristics and the natural frequency of the slope are clarified according to the Fourier spectrum and modal analysis. Low-order and high-order natural frequencies mainly cause the overall and local dynamic deformation of the surface slope, respectively. Moreover, the seismic energy of the Hilbert energy spectrum and marginal spectrum is mainly concentrated in the low-order and high-order natural frequency components, respectively. The difference in the seismic response between the slip mass and slip bed is the main triggering factor of a landslide based on the time-frequency joint analysis. The dynamic failure mechanism of the slope is identified: cracks first occur in the structural planes; then, with the earthquake excitation continuing, cracks further expand, deepen and penetrate, thus gradually forming the slip plane; finally, the overall shear failure of the surface slope appears.
•A time-frequency joint analysis method was proposed to investigate the dynamic response of a bedding rock slope.•The terrain and geological effects of a bedding slope under seismic excitation were analyzed.•The natural frequency had an effect on the dynamic deformation characteristics of the bedding slope.•The dynamic failure mechanism of the bedding slope using the time-frequency joint analysis method was discussed.
Increasing evidence has shown that mesenchymal stem cells (MSCs) yield a favorable therapeutic benefit for thermal burn skin wounds. Human amniotic MSCs (hAMSCs) derived from amniotic membrane have ...multilineage differentiation, immunosuppressive, and anti-inflammatory potential which makes them suitable for treating skin wounds. However, the exact effects of hAMSCs on the healing of thermal burn skin wounds and their potential mechanisms are not explored.
hAMSCs were isolated from amniotic membrane and characterized by RT-PCR, flow cytometry, immunofluorescence, and tumorigenicity test. We assessed the effects of hAMSCs and hAMSC conditional medium (CM) on wound healing in a deep second-degree burn injury model of mice. We then investigated the biological effects of hAMSCs and hAMSC-CM on the apoptosis and proliferation of heat stress-injured human keratinocytes HaCAT and dermal fibroblasts (DFL) both in vivo and in vitro. Next, we explored the underlying mechanisms by assessing PI3K/AKT and GSK3β/β-catenin signaling pathways in heat injured HaCAT and DFL cells after hAMSCs and hAMSC-CM treatments using PI3K inhibitor LY294002 and β-catenin inhibitor ICG001. Antibody array assay was used to identify the cytokines secreted by hAMSCs that may activate PI3K/AKT signaling pathway.
Our results showed that hAMSCs expressed various markers of embryonic stem cells and mesenchymal stem cells and have low immunogenicity and no tumorigenicity. hAMSC and hAMSC-CM transplantation significantly promoted thermal burn wound healing by accelerating re-epithelialization with increased expression of CK19 and PCNA in vivo. hAMSCs and hAMSC-CM markedly inhibited heat stress-induced apoptosis in HaCAT and DFL cells in vitro through activation of PI3K/AKT signaling and promoted their proliferation by activating GSK3β/β-catenin signaling. Furthermore, we demonstrated that hAMSC-mediated activation of GSK3β/β-catenin signaling was dependent on PI3K/AKT signaling pathway. Antibody array assay showed that a panel of cytokines including PAI-1, C-GSF, periostin, and TIMP-1 delivered from hAMSCs may contribute to the improvement of the wound healing through activating PI3K/AKT signaling pathway.
Our results demonstrated that hAMSCs and hAMSC-CM efficiently cure heat stress-induced skin injury by inhibiting apoptosis of skin cells and promoting their proliferation through activating PI3K/AKT signaling pathway, suggesting that hAMSCs and hAMSC-CM may provide an alternative therapeutic approach for the treatment of skin injury.
SUMMARY
DNA methylation is an important epigenetic mark. In plants, de novo DNA methylation occurs mainly through the RNA‐directed DNA methylation (RdDM) pathway. Researchers have previously inferred ...that a flowering regulator, MULTICOPY SUPPRESSOR OF IRA1 4 (MSI4)/FVE, is involved in non‐CG methylation at several RdDM targets, suggesting a role of FVE in RdDM. However, whether and how FVE affects RdDM genome‐wide is not known. Here, we report that FVE is required for DNA methylation at thousands of RdDM target regions. In addition, dysfunction of FVE significantly reduces 24‐nucleotide siRNA accumulation that is dependent on factors downstream in the RdDM pathway. By using chromatin immunoprecipitation and sequencing (ChIP‐seq), we show that FVE directly binds to FVE‐dependent 24‐nucleotide siRNA cluster regions. Our results also indicate that FVE may function in RdDM by physically interacting with RDM15, a downstream factor in the RdDM pathway. Our study has therefore revealed that FVE, by associating with RDM15, directly regulates DNA methylation and siRNA accumulation at a subset of RdDM targets.
Significance Statement
The RNA‐directed DNA methylation (RdDM) pathway is one of the most important DNA methylation pathways in plants. In this manuscript, we show that FVE is required for DNA methylation and for 24‐nucleotide siRNA accumulation at a subset of RdDM targets. Moreover, FVE physically interacts with RDM15 and shares DNA methylation targets with RDM15 in the genome. Our results support the notion that FVE functions in RdDM, particularly in RNA polymerase V‐mediated downstream step.
In this letter, the characteristic basis functions (CBFs) are utilized to enhance the compressive sensing (CS) technique to analyze the bistatic scattering problems of three‐dimensional targets. The ...CS technique can efficiently analyze the bistatic scattering problems by establishing an underdetermined linear equation instead of traditional full‐rank dense impedance matrix equation. However, the CS method is limited to two‐dimensional targets. The reason is that the induced currents of the three‐dimensional target expressed by Rao‐Wilton‐Glisson basis functions are not sparse on the commonly sparse basis, since the field source has no orderly distribution when the target is modeled and discretized by commercial software. In order to solve this problem, the CBFs are used in this letter as the sparse basis to improve the sparsity of the induced currents. The numerical results of different targets are presented to validate the accuracy and efficiency of the proposed method.
ACSS1/2 converts acetate into acetyl‐coenzyme A, which contributes to histone acetylation in the mitochondria and cytoplasm. Zygotic genome activation (ZGA) is critical for embryo development ...involving drastic histone modification. An efficient crRNAs‐Cas13a targeting strategy was employed to investigate the ACSS1/2 function during ZGA. The results showed that nuclear accumulation of ACSS1 and ACSS2 occurs during ZGA. Knockdown of ACSS1/2 did not affect blastocyst formation when using a normal medium. On culturing embryos in a medium with acetate and no pyruvate (−P + Ace), knockdown of ACSS1 did not affect histone acetylation levels but significantly reduced ATP levels, whereas knockdown of ACSS2 significantly reduced histone acetylation levels in porcine embryos. Inhibition of fatty acid beta‐oxidation by etomoxir significantly reduced ATP levels, which could be restored by acetate. The histone acetylation levels in the ACSS1 and ACSS2 knockdown groups both decreased considerably after etomoxir treatment. Moreover, acetate showed dose‐dependent effects on SIRT1 and SIRT3 levels when under metabolic stress. The C‐terminus of ACSS1 regulated the nuclear translocation. In conclusion, ACSS1/2 helps to maintain ATP and histone acetylation levels in porcine early embryos under metabolic stress during ZGA.
New roles of acetyl‐CoA synthases have been implicated in early embryo development. ACSS1 and ACSS2 restore the histone acetylation level and promote early embryo development when under metabolic stress.
Melatonin, a major hormone of the pineal gland, exerts many beneficial effects on mitochondria. Several studies have shown that melatonin can protect against toxin‐induced oocyte quality impairment ...during maturation. However, there is little information regarding the beneficial effects of melatonin on toxin‐exposed early embryos, and the mechanisms underlying such effects have not been determined. Rotenone, a chemical widely used in agriculture, induces mitochondrial toxicity, therefore, damaging the reproductive system, impairing oocyte maturation, ovulation, and fertilization. We investigated whether melatonin attenuated rotenone exposure‐induced impairment of embryo development by its mitochondrial protection effect. Activated oocytes were randomly assigned to four groups: the control, melatonin treatment, rotenone‐exposed, and “rotenone + melatonin” groups. Treatment with melatonin abrogated rotenone‐induced impairment of embryo development, mitochondrial dysfunction, and ATP deficiency, and significantly decreased oxidative stress and apoptosis. Melatonin also increased SIRT1 and PGC‐1α expression, which promoted mitochondrial biogenesis. SIRT1 knockdown or pharmacological inhibition abolished melatonin's ability to revert rotenone‐induced impairment. Thus, melatonin rescued rotenone‐induced impairment of embryo development by reducing ROS production and promoting mitochondrial biogenesis. This study shows that melatonin rescues toxin‐induced impairment of early porcine embryo development by promoting mitochondrial biogenesis.
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