Nitric oxide (NO) has been shown to play an important role in the plant response to biotic and abiotic stresses in Arabidopsis mutants with lower or higher levels of endogenous NO. The exogenous ...application of NO donors or scavengers has also suggested an important role for NO in plant defense against environmental stress. In this study, rice plants under drought and high salinity conditions showed increased nitric oxide synthase (NOS) activity and NO levels. Overexpression of rat neuronal NO synthase (nNOS) in rice increased both NOS activity and NO accumulation, resulting in improved tolerance of the transgenic plants to both drought and salt stresses. nNOS-overexpressing plants exhibited stronger water-holding capability, higher proline accumulation, less lipid peroxidation and reduced electrolyte leakage under drought and salt conditions than wild rice. Moreover, nNOS-overexpressing plants accumulated less H2O2, due to the observed up-regulation of OsCATA, OsCATB and OsPOX1. In agreement, the activities of CAT and POX were higher in transgenic rice than wild type. Additionally, the expression of six tested stress-responsive genes including OsDREB2A, OsDREB2B, OsSNAC1, OsSNAC2, OsLEA3 and OsRD29A, in nNOS-overexpressing plants was higher than that in the wild type under drought and high salinity conditions. Taken together, our results suggest that nNOS overexpression suppresses the stress-enhanced electrolyte leakage, lipid peroxidation and H2O2 accumulation, and promotes proline accumulation and the expression of stress-responsive genes under stress conditions, thereby promoting increased tolerance to drought and salt stresses.
A systematic interrogation of male germ cells is key to complete understanding of molecular mechanisms governing spermatogenesis and the development of new strategies for infertility therapies and ...male contraception. Here we develop an approach to purify all types of homogeneous spermatogenic cells by combining transgenic labeling and synchronization of the cycle of the seminiferous epithelium, and subsequent single-cell RNA-sequencing. We reveal extensive and previously uncharacterized dynamic processes and molecular signatures in gene expression, as well as specific patterns of alternative splicing, and novel regulators for specific stages of male germ cell development. Our transcriptomics analyses led us to discover discriminative markers for isolating round spermatids at specific stages, and different embryo developmental potentials between early and late stage spermatids, providing evidence that maturation of round spermatids impacts on embryo development. This work provides valuable insights into mammalian spermatogenesis, and a comprehensive resource for future studies towards the complete elucidation of gametogenesis.
The development of the plant root system is highly plastic, which allows the plant to adapt to various environmental stresses. Salt stress inhibits root elongation by reducing the size of the root ...meristem. However, the mechanism underlying this process remains unclear. In this study, we explored whether and how auxin and nitric oxide (NO) are involved in salt-mediated inhibition of root meristem growth in Arabidopsis (Arabidopsis thaliana) using physiological, pharmacological, and genetic approaches. We found that salt stress significantly reduced root meristem size by down-regulating the expression ofPINFORMED (PIN)genes, thereby reducing auxin levels. In addition, salt stress promoted AUXIN RESISTANT3 (AXR3)/INDOLE-3-ACETIC ACID17 (IAA17) stabilization, which repressed auxin signaling during this process. Furthermore, salt stress stimulated NO accumulation, whereas blocking NO production with the inhibitorNω
-nitro-L-arginine-methylester compromised the salt-mediated reduction of root meristem size,PINdown-regulation, and stabilization of AXR3/IAA17, indicating that NO is involved in salt-mediated inhibition of root meristem growth. Taken together, these findings suggest that salt stress inhibits root meristem growth by repressingPINexpression (thereby reducing auxin levels) and stabilizing IAA17 (thereby repressing auxin signaling) via increasing NO levels.
•Micro-CT has been used to investigate various cement-based materials.•Threshold determination from micro-CT images is crucial for phase identification.•Microstructure and property relations are ...effectively correlated through micro-CT.
Cement-based materials are generally highly heterogeneous, and their material properties are strongly affected by the characteristics and spatial distributions of each constituent. However, it is difficult to characterize the compounds inside these materials without destroying them. Micro-computed tomography (micro-CT) is an approach that enables the investigation of the inner structure of a material without damaging the specimen. From micro-CT, a series of cross-sectional images of a material with a pixel size of a few micrometers can be achieved, which can be used to evaluate the characteristics of the material. In this study, the use of micro-CT for various cement-based materials, e.g., lightweight concrete and high-performance concrete, is summarized. The characteristics of pores and solid phases, such as the volume fraction and spatial distribution, are also analyzed, and their relations with the physical properties of cement-based materials are reviewed and presented. It is shown that micro-CT has a great potential not only for investigating the performance of existing materials but also for developing new cement-based materials.
Most ABC transporters are engaged in transport of various compounds, but its subfamily F lacks transmembrane domain essential for chemical transportation. Thus the function of subfamily F remains ...further elusive.
Here, we identified General Control Non-Repressible 20 (GCN20), a member of subfamily F, as new factor for DNA damage repair in root growth. While gcn20-1 mutant had a short primary root with reduced meristem size and cell number, similar primary root lengths were assayed in both wild-type and GCN20::GCN20 gcn20-1 plants, indicating the involvement of GCN20 in root elongation. Further experiments with EdU incorporation and comet assay demonstrated that gcn20-1 displays increased cell cycle arrest at G2/M checkpoint and accumulates more damaged DNA. This is possible due to impaired ability of DNA repair in gcn20-1 since gcn20-1 seedlings are hypersensitive to DNA damage inducers MMC and MMS compared with the wild type plants. This note was further supported by the observation that gcn20-1 is more sensitive than the wild type when subjected to UV treatment in term of changes of both fresh weight and survival rate.
Our study indicates that GCN20 functions in primary root growth by modulating DNA damage repair in Arabidopsis. Our study will be useful to understand the functions of non-transporter ABC proteins in plant growth.
Tongue cancer remains a massive threat to public health due to the high rate of metastasis. Tumor cell epithelial‐mesenchymal transition (EMT), which can be induced by transforming growth factor β1 ...(TGFβ1), has been regarded as a significant contributor to cancer invasion and migration. In our previous study, long noncoding RNA (lncRNA) MALAT1/miR‐124/JAG1 axis modulates the growth of tongue cancer. In addition to metastasis‐associated lung adenocarcinoma transcript 1 (MALAT1), another lncRNA, urothelial cancer associated 1 (UCA1), can promote EMT and cancer metastasis. In the present study, UCA1 was overexpressed in tongue cancer tissues and cell lines. UCA1 overexpression was correlated to the poorer prognosis of patients with tongue cancer. UCA1 knockdown significantly suppressed TGFβ1‐induced tongue cancer cell invasion and EMT by decreasing vimentin and increasing E‐cadherin. Regarding the molecular mechanism, UCA1 could directly bind to microRNA‐124 (miR‐124) and negatively regulate each other. UCA1 knockdown ameliorated, whereas miR‐124 inhibition exacerbated TGFβ1‐induced EMT and invasion in tongue cancer cells through miR‐124 downstream jagged 1 (JAG1) and Notch signaling. Moreover, miR‐124 inhibition partially impaired the effect of UCA1 knockdown. In tongue cancer tissues, miR‐124 expression was remarkably decreased, whereas JAG1 mRNA expression was increased. miR‐124 was negatively correlated with UCA1 and JAG1. UCA1 and JAG1 were positively correlated. In summary, we provided a novel mechanism by which the EMT process and cancer cell invasion in tongue cancer could be modulated from the perspective of lncRNA‐miRNA‐mRNA regulation.
Urothelial cancer associated 1 (UCA1) could directly bind to microRNA‐124 (miR‐124) and negatively regulate each other. UCA1 knockdown ameliorated, whereas miR‐124 inhibition exacerbated transforming growth factor β1 (TGFβ1)‐induced epithelial‐mesenchymal transition (EMT) and invasion in tongue cancer cells through miR‐124 downstream jagged 1 (JAG1) and Notch signaling. Moreover, miR‐124 inhibition partially impaired the effect of UCA1 knockdown.
Background
Previous studies have shown that diffusion‐weighted imaging (DWI) is sensitive to myocardial fibrosis in ischemic and nonischemic cardiomyopathy.
Purpose
To explore the prognostic value of ...apparent diffusion coefficient (ADC) for detecting myocardial fibrosis and its relationship to the contractile function in hypertrophic cardiomyopathy (HCM).
Study Type
Prospective.
Population
A total of 45 HCM patients and 20 controls.
Field Strength/Sequence
3.0T cardiac MRI. The cardiac MR sequences included cine, T1 mapping, and DWI.
Assessment
According to the presence of late gadolinium enhancement (LGE) and the extracellular volume (ECV) values (+2 SD of control subjects), respectively, reader W and reader J assessed the value of ADC of each segment for detecting myocardial fibrosis and its relationship to impaired contractile function in HCM patients.
Statistical Tests
Independent sample t‐test, Pearson analysis, and intraclass correlation (ICC).
Results
The value of ECV was 23.6 ± 3.0% for control. ECV ≥ 29.6% and ECV < 29.6% groups were classified. ADC values in the ECV ≥ 29.6% group were significantly increased compared to the ECV < 29.6% group, (2.41 ± 0.23 μm2/ms vs. 2.03 ± 0.16 μm2/ms, P < 0.005). Compared to the LGE – group, ECV (32.1 ± 2.3% vs. 29.0 ± 2.8%, P < 0.005) and ADC (2.60 ± 0.18 μm2/ms vs. 2.10 ± 0.07 μm2/ms, P < 0.005) values were significantly increased in the LGE + group. ADC values were linearly associated with ECV values (R2 = 0.65) in HCM patients. ADC values were linearly associated with circumferential and longitudinal strain (R2 = 0.60, R2 = 0.46), as well as circumferential, longitudinal, and radial strain rate (R2 = 0.13, R2 = 0.25, R2 = 0.17, respectively).
Data Conclusion
Contractile dysfunction in HCM is predominantly associated with ADC, which is a feasible alternative to ECV and LGE for detecting myocardial fibrosis.
Level of Evidence: 1
Technical Efficacy: Stage 2
J. Magn. Reson. Imaging 2018;48:1139–1146.
Direct conversion of hydrocarbons into value-added chemicals can be realized through activation and functionalization of C-H bonds so as to meet the requirements of the atomic economy and sustainable ...development strategy of chemistry. By virtue of the mild reaction conditions and high product selectivity, heterogeneous photocatalysis has attracted considerable attention. In this feature article, we focus on the catalyst modification strategies developed in recent years for photocatalytic activation of C-H bonds. The influence of the modifications on reaction activity and selectivity is further discussed by analyzing the mechanism of photocatalytic C-H bond activation. We hope that this feature article would provide useful guidance for the preparation of new photocatalysts for hydrocarbon conversion.
This feature article summarizes the recent progress in the modification of heterogeneous photocatalysts for photocatalytic hydrocarbons' C-H bond activation.
Microstructural characteristics and properties of foamed concrete, a cellular lightweight cement paste with entrained air voids, are investigated. The complex 3D microstructures of the foamed ...concrete with different densities are obtained by micro-CT imaging and binarized as two-phase (pore/solid) materials by image processing. The mechanical responses of the microstructures are evaluated by simulations within the phase-field fracture model, and the input material parameters for simulations are identified. Microstructural characteristics and properties from experiments and simulations are correlated. In particular, linear attenuation coefficients for the solid phase in micro-CT images correlate with input material parameters. These correlations can serve to determine solid-phase input material parameters in foamed concretes with different densities. The behavior of foamed-concrete binders, modeled as multi-phase solids, should thus be evaluated more accurately through simulations, based on the observed correlations.
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