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ABSTRACTTo observe the role of transforming growth factor beta-activated kinase 1 (TAK1)/p38 MAPK/TGF-β1 signal pathway plays in oxidative stress and apoptosis in human renal tubular epithelial cells (HK-2) under high glucose induction. HK-2 cells were cultured in high glucose medium with and without TAK1 inhibitor 5Z-7-oxozeaenol. TUNEL and flow cytometry were used to detect cell apoptosis. The protein expression of TAK1, TGF-β1, Bax and Bcl-2 was detected by immunofluorescence. Meanwhile, flow cytometry was used to detect the production of reactive oxygen species (ROS), and MitoSOX staining was performed to detect the production of mitochondrial ROS. Moreover, real-time quantitative PCR and Western blotting was used to measure the expression of TAK1, TGF-β1, NOX1, NOX4 and HO-1, Bax, Bcl-2, p38MAPK, p-p38MAPK and TGF-β1. Results showed that high glucose up-regulated the protein expression of p-TAK1, p-p38 MAPK and TGF-β1, which induced the aggravation of oxidative stress by promoting the production of ROS, thus promote the apoptosis in HK-2 cells. However, addition of 5z −7-oxozeaenol in HK-2 cells reversed all the above functions induced by high glucose. Another experimental result also showed that SB203580, a p38MAPK inhibitor can down-regulated TGF-β1 expression and reduce ROS production, thus alleviate cell apoptosis in TAK1 overexpression group. In summary, high glucose intervention could activate TAK1 and promote apoptosis in HK-2 cells. Inhibition of TAK1 expression could block p38 MAPK/TGF-β1 signaling pathway and reduce ROS production and oxidative stress, which may be one of the signal pathways of TAK1 to reduce apoptosis of HK-2 cells induced by high glucose.Abbreviations: DN, Diabetic nephropathy; TAK1, transforming growth factor β-activated kinase-1; TGF-β, transforming growth factor-β; NG, normal glucose; HG, high glucose; p38 MAPK, p38 mitogen-activated protein kinase; ROS, reactive oxygen species.

AbstractDrought is one of the most severe environmental stressors hampering maize (Zea maysL.) production worldwide. Therefore, revealing the molecular mechanisms underpinning maize drought tolerance is critical for guiding drought resistance breeding and ensuring global food security. Herein, we performed a data-independent acquisition (DIA) proteomics-based comparative analysis of the proteome responses of two contrasting maize hybrids (drought-tolerant NongDan 476 and drought-sensitive ZhongXin 978) exposed to 12 days of water-deficit (drought) treatment at the kernel filling stage. Resultantly, our DIA-based analysis approach identified a total of 826 differentially abundant proteins (DAPs), among which 7 DAPs were specifically accumulated in tolerant genotype ND 476 under drought treatment conditions. Moreover, our results showed that there were significant differences in drought stress responses between the two hybrids at the proteomic level. Predominantly, our analysis revealed that maize drought tolerance is attributed to some key proteins such as chaperones, DNA replication related enzymes, vicilin and ABA-responsive RAB17 protein, participating in several metabolic networks including starch and sucrose metabolism, terpenoid backbone biosynthesis, cyanoamino acid metabolism and carbon metabolism pathways. Our findings provide further insights into the drought stress tolerance mechanisms in maize at the grain filling period, in addition to useful reference data for maize drought resistance breeding.

AbstractDrought is a major abiotic stress factor that affects the yield of maize (Zea maysL.) during the grain filling period. Therefore, it is critical to reveal the molecular mechanisms underlying maize drought stress tolerance. To analyze the characteristics and functions of differentially abundant proteins (DAPs) in response to drought stress during the maize kernel-filling stage, here, two maize hybrid varieties with contrasting drought tolerance (tolerant ND476 and sensitive ZX978) were subjected to water sufficient (control) and water deficit (drought) treatment conditions for 12 days at the grain filling stage. Physiological assays and leaf proteome analysis were performed. We conducted iTRAQ analysis on 12 samples from 4 groups and obtained 1,655 DAPs. Amongst these, five essential sets of drought responsive DAPs were identified by bioinformatics techniques. Four significantly enriched metabolic pathways were identified in ND476, which were shown to be associated with the ribosome, metabolic, basal transcription factors and photosynthesis pathways. Further, the phenotypic characterization and qRT-PCR analysis confirmed our iTRAQ sequencing data. Remarkably, significantly higher drought tolerance of ND476 may be attributed to the following responses: (a) oxidoreductase, peroxidase and hydrolytic enzyme activities to promote cell redox homeostasis maintenance; (b) elevated expression of stress defense proteins; and (c) reduced synthesis of redundant proteins in order to help plants preserve energy to fight drought stress. In conclusion, these results offer more insights into the molecular mechanisms underlying maize drought tolerance at the grain filling stage and can be a foundational basis for molecular breeding of drought tolerant maize varieties.

Drought is a main abiotic stress factor hindering plant growth, development, and crop productivity. Therefore, it is crucial to understand the mechanisms by which plants cope with drought stress. Here, the function of the maize peroxidase gene ZmPRX1in drought stress tolerance was investigated by measurement of its expression in response to drought treatment both in a ZmPRX1overexpression line and a mutant line. The higher root lignin accumulation and seedling survival rate of the overexpression line than that of the wild type or mutant support a role for ZmPRX1in maize drought tolerance by regulating root development and lignification. Additionally, yeast one-hybrid, Dule luciferase and ChIP-qPCR assays showed that ZmPRX1is negatively regulated by a nuclear-localized ZmWRKY86 transcription factor. The gene could potentially be used for breeding of drought-tolerant cultivars.

ABSTRACTIn this study, the molecular mechanism underlying ethephon-induced shortened internodes in maize was investigated using Zhengdan958 maize variety. The ethephon treatment was performed by spraying 225 mL/ha Ethephon 40% SL onto the foliage at the eight-expanded-leaves stage. The differentially expressed genes in the young internodes under ethephon treatment were identified through methylation-sensitive amplified fragment length polymorphism (MSAP), start codon targeted polymorphism (SCoT) and cDNA-amplified fragment length polymorphism (AFLP) analyses. MSAP results showed the methylation sites were widely distributed in both the ethephon-treated (at 27.8%) and control plants (30.1%). This suggested that ethephon treatment modified the methylation patterns; with 3.0% of the sites being hyper-methylated and 7.3% demethylated compared with the control. Based on SCoT analysis, 148 transcript derived fragments (TDFs) were obtained in the ethephon-treated plants. Among them, 38 were up-regulated (25.7%) and 47 down-regulated (31.8%). cDNA-AFLP analysis using 70 primer pairs identified 1635 TDFs in the ethephon-treated and the control plants. Of these, 600 and 564 TDFs were up- and down-regulated by the ethephon treatment, respectively. BLASTX analysis on 50 (randomly selected) differentially expressed TDFs divided them into several categories based on their putative biological functions: signal transduction (6%), resistance-related (14%), energy and metabolism (22%), transcription (4%), cell apoptosis (2%), unknown functional proteins (42%) and unknown genes (10%). Our results revealed that ethephon treatment could induce DNA methylation variation principally by increasing the demethylation tendency. This is suggested to play roles in stress-defence genes expression regulation and the differentially expressed genes could be associated with shortened internodes in maize.

ABSTRACTIn this study, a watermelon (Citrullus lanatus) zeaxanthin epoxidase gene, ClZE, was isolated by reverse transcription-polymerase chain reaction (PCR) together with RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE). The full cDNA sequence of ClZEis 2535 bp in length containing a 1998 bp open reading frame (ORF) that encodes 665 amino acids. ClZEwas shown to share high homology with the putative ZEgenes in other plant species. Prediction analysis revealed that ClZEbears two large conservative domains, including Pyr_redox and FHA (forkhead-associated domain). Phylogenetic analysis suggested that ClZEshares high similarity (94.8%) with CsZEfrom Cucumis sativus, but is far from the ZEgenes of other species. Prokaryotic expression indicated that ClZE possessed the apparent molecular mass consistent with its calculated molecular mass of 73.1 KDa. Based on quantitative real-time PCR (qRT-PCR), ClZEwas shown to be down-regulated under chilling–low irradiance stress in watermelon leaves. Transgenic Arabidopsislines harbouring ClZEwere generated to test the gene function in mediating plant response to chilling stress. The results indicated that the transgenic lines exhibited decreased non-photochemical quenching (NPQ) and maximum quantum efficiency of photosystem II (PSII) photochemistry (Fv/Fm), increased activities of peroxidase (POD), superoxide dismutase (SOD) and elevated content of malondialdehyde (MDA) relative to the wild type (WT) under chilling–low irradiance stress. In addition, overexpression of ClZEresulted in impaired xanthophyll cycle and aggravated PSII photoinhibition under chilling–low irradiance. All the results together suggested that ClZEplays major roles in regulating the photoinhibition behaviour.

Oxidative stress is implicated in the pathogenesis of diabetic kidney injury. SS-31 is a mitochondria-targeted tetrapeptide that can scavenge reactive oxygen species (ROS). Here, we investigated the effect and molecular mechanism of mitochondria-targeted antioxidant peptide SS-31 on injuries in diabetic kidneys and mouse mesangial cells (MMCs) exposed to high-glucose (HG) ambience. CD-1 mice underwent uninephrectomy and streptozotocin treatment prior to receiving daily intraperitoneal injection of SS-31 for 8 wk. The diabetic mice treated with SS-31 had alleviated proteinuria, urinary 8-hydroxy-2-deoxyguanosine level, glomerular hypertrophy, and accumulation of renal fibronectin and collagen IV. SS-31 attenuated renal cell apoptosis and expression of Bax and reversed the expression of Bcl-2 in diabetic mice kidneys. Furthermore, SS-31 inhibited expression of transforming-growth factor (TGF)-β1, Nox4, and thioredoxin-interacting protein (TXNIP), as well as activation of p38 MAPK and CREB and NADPH oxidase activity in diabetic kidneys. In vitro experiments using MMCs revealed that SS-31 inhibited HG-mediated ROS generation, apoptosis, expression of cleaved caspase-3, Bax/Bcl-2 ratio, and cytochrome c(cyt c) release from mitochondria. SS-31 normalized mitochondrial potential (ΔΨm) and ATP alterations, and inhibited the expression of TGF-β1, Nox4, and TXNIP, as well as activation of p38 MAPK and CREB and NADPH oxidase activity in MMCs under HG conditions. SS-31 treatment also could reverse the reduction of thioredoxin (TRX) biologic activity and upregulate expression of thioredoxin 2 (TRX2) in MMCs under HG conditions. In conclusion, this study demonstrates a protective effect of SS-31 against HG-induced renal injury via an antioxidant mechanism in diabetic nephropathy.

Inflammation is an important pathophysiological mechanism in diabetic nephropathy (DN). Tubular epithelial cell-myofibroblast transdifferentiation (TEMT), which can be induced by many cytokines, is an important event in DN. Oncostatin M (OSM), an inflammatory cytokine, can induce TEMT in vitro. The suppressors of cytokine signaling (SOCS) proteins are negative-feedback regulators of cytokine signaling. The purpose of this study was to investigate the role of SOCS in DN. The results demonstrated that overexpression of SOCS ameliorated proteinuria, the expression of α-SMA and OSM in tubular epithelial cells, and interstitial extracellular matrix accumulation in the renal tissue of CD-1 mice. In addition, our previous studies indicated that OSM induced TEMT by activating the JAK/STAT pathway, which could be inhibited by SOCS. These results indicate that overexpression of SOCS has a therapeutic effect in DN.

Erbin belongs to the LAP protein family. Originally, Erbin was described as a Her2-interacting protein. Recent studies demonstrated that Erbin could inhibit the Ras-mediated activation of the mitogen-activated protein kinase (MAPK), nuclear factor-B (NF-B) and transforming growth factor (TGF-) signaling pathways. It suggests that Erbin may function as a signaling molecule. The functions of Erbin in determining cell polarity and cell adhesion have been well described. This review mainly focuses on the recent findings in regulation of signaling pathways by Erbin.

In order to solve the problem of gas accumulation in the upper corner caused by large gas emission due to high mining intensity in the fully mechanized top coal caving face of Wangjialing coal mine, we used numerical simulation method combined with the key stratum layer control theory to study the roof caving trend and development law of inclined mining fissure. Then we analyzed the evolution process of goaf fissure with the advance of the working face and the development height of roof fissure. Finally, we got the best hole layout position and drilling structure of near horizontal high-level directional long drilling. The practice indicates that we achieved nice gas extraction effect by setting near horizontal high-level directional long drilling borehole according to the above research results. The maximum net extraction volume of a single borehole is 2.10 m3/ min, the maximum extraction volume fraction is 31.39%, and the total net amount of gas extracted from the four boreholes under construction is 289900 m3. The gas concentration in the upper corner of the working face decreased to 0.46% during extraction, and the problem of gas overrun in the upper corner was effectively solved.

Abstract: The lung tissues of ddY mice from fetal day 16 to postnatal 12 months were incubated in Eagle's MEM containing3H-thymidine. DNA synthesis and morphological changes in the pulmonary tissue cells of mice from 10 different age groups were studied by light and electron microscopic radioautography. A peak in the labeling indices (LI) of the type 1 cells was found on the third day after birth, while that of the type 2, interstitial and endothelial cells was found on fetal day 16. Then they gradually decreased with age. Silver grains were located mainly in nuclei, while a few were seen in mitochondria.