Search

DNA methylation plays a crucial role in suppressing mobilization of transposable elements and regulation of gene expression. A number of studies have indicated that DNA methylation pathways and patterns exhibit distinct properties in different species, including Arabidopsis, rice, and maize. Here, we characterized the function of DDM1 in regulating genome-wide DNA methylation in maize. Two homologs of ZmDDM1 are abundantly expressed in the embryo and their simultaneous disruption caused embryo lethality with abnormalities in cell proliferation from the early stage of kernel development. We establish that ZmDDM1 is critical for DNA methylation, at CHG sites, and to a lesser extent at CG sites, in heterochromatic regions, and unexpectedly, it is required for the formation of m CHH islands. In addition, ZmDDM1 is indispensable for the presence of 24-nt siRNA, suggesting its involvement in the RdDM pathway. Our results provide novel insight into the role of ZmDDM1 in regulating the formation of m CHH islands, via the RdDM pathway maize, suggesting that, in comparison to Arabidopsis, maize may have adopted distinct mechanisms for regulating m CHH.

Root hair, a special type of tubular-shaped cell, outgrows from the root epidermal cell and plays important roles in the acquisition of nutrients and water, as well as interactions with biotic and abiotic stresses. Studies in the model plant Arabidopsis have revealed that root-hair initiation and elongation are hierarchically regulated by a group of basic helix-loop-helix (bHLH) transcription factors (TFs). However, knowledge regarding the regulatory pathways of these bHLH TFs in controlling root hair growth remains limited. In this study, RNA-seq analysis was conducted to profile the transcriptome in the elongating maize root hair and >1000 genes with preferential expression in root hair were identified. A consensus cis-element previously featured as the potential bHLH-TF binding sites was present in the regulatory regions for the majority of the root hair-preferentially expressed genes. In addition, an individual change in ZmLRL5, the highest-expressed bHLH-TF in maize root hair resulted in a dramatic reduction in the elongation of root hair, and rendered the growth of root hair hypersensitive to translational inhibition. Moreover, RNA-seq, yeast-one-hybrid and ribosome profile analysis suggested that ZmLRL5 may function as a key player in orchestrating the translational process by directly regulating the expression of translational processes/ribosomal genes during maize root hair growth.

Objective This study aimed to explore the effect of bronchopulmonary dysplasia (BPD) on the early intellectual development of preterm infants. Methods From 2011 to 2015, 83 preterm infants diagnosed with BPD were recruited to the BPD group, and 89 preterm infants without BPD and 98 healthy term infants were randomly recruited to the non-BPD and term group, respectively. Neural and intellectual development according to the Gesell Development Scale were evaluated and compared between groups at 0-3 months, 3-6 months, 6-9 months, and 9-12 months of adjusted age for preterm infants and real age for term infants. Multivariate logistic regression was used to determine the associations between BPD and adverse neurological outcomes at 9-12 months of adjusted age. Results Compared to term infants, preterm infants had significantly lower developmental quotients for adaptability, gross motor, fine motor, language and social intercourse skills. At follow-up, deficits in one or more neurofunctions related to adaptability, gross motor, fine motor, language and social intercourse skills were significantly more frequent in preterm children with BPD than in those with no history of BPD. BPD was independently associated with adverse neurological outcomes at 9-12 months of adjusted age in preterm infants. Conclusions Early intelligence disturbances occurred significantly more frequently in BPD infants than non-BPD infants. Monitoring of the development of the nervous system in BPD infants should be strengthened. This article is protected by copyright. All rights reserved.

The intelligent design of multifunctional nanoplatforms is critical for cancer therapy. Herein, NaGdF4 :Er,Yb@NaGdF4 :Nd@Cu(II) boron-imidazolate frameworks (denoted as CSNPs@Cu-BIF) nanoassemblies are designed and fabricated. Upon a single 808 nm laser irradiation, the nanoassemblies not only show the outstanding photothermal conversion capacity (η = 41.7%) but also generate cytotoxic reactive oxygen species through an in situ Fenton-like reaction and fluorescence resonance energy transfer. Importantly, the nanoassemblies simultaneously introduce remarkable antitumor efficacy via photothermal/photodynamic/chemodynamic combination therapy both in vitro and in vivo. To improve the therapeutic effect of solid tumor ablation, it is highly desirable to monitor the treatment process in real-time. Multiclinical imaging modalities of ultrasonography are employed to systematically investigate the ablation mechanism of solid tumors in vivo. Furthermore, the significant difference between the eigen temperature of CSNPs@Cu-BIF nanoassemblies obtained by the temperature-sensitive emission bands signal changes and the apparent temperature recorded by the thermal imaging camera is 14.55 K at equilibrium. This current work therefore supplies an alternative strategy in temperature feedback-controlled accurate cancer therapy.

Food chain systems (FCSs), which begin in agricultural production and end in consumption and waste disposal, play a significant role in China's rising greenhouse gas (GHG) emissions. This article uses scenario analysis to show China's potential trajectories to a low-carbon FCS. Between 1996 and 2010, the GHG footprint of China's FCSs increased from 1,308 to 1,618 megatonnes of carbon dioxide equivalent (Mt CO2-eq), although the emissions intensity of all food categories, except for aquatic food, recorded steep declines. We project three scenarios to 2050 based on historical trends and plausible shifts in policies and environmental conditions: reference scenario; technology improvement scenario; and low GHG emissions scenario. The reference scenario is based on existing trends and exhibits a large growth in GHG emissions, increasing from 1,585 Mt CO2-eq in 2010 to 2,505 Mt CO2-eq in 2050. In the technology improvement scenario, emissions growth is driven by rising food demand, but that growth will be counterbalanced by gains in agricultural technology, causing GHG emissions to fall to 1,413 Mt CO2-eq by 2050. Combining technology improvement with the shift to healthier dietary patterns, GHG emissions in the low GHG emissions scenario will decline to 946 Mt CO2-eq in 2050, a drop of 41.5% compared with the level in 2010. We argue that these are realistic projections and are indeed indicative of China's overall strategy for low-carbon development. Improving agricultural technology and shifting to a more balanced diet could significantly reduce the GHG footprint of China's FCSs. Furthermore, the transition to a low-carbon FCS has potential cobenefits for land sustainability and public health.

China's rapid economic growth has been fueled by industrialization and urbanization. Given its export focus, this industrialization was spatially concentrated in the coastal eastern cities. Over the last decade, a spatial transformation has taken place leading to a deindustrialization of the rich coastal cities and sharp industrial growth in the inland cities. This survey examines recent work that studies the economic geography of industrial production, pollution, and quality of life in China's cities. We focus on the interaction between firms, local governments, and the central government that together determine the new economic geography of industry and pollution within China.

Environmental pollution has become a major health concern and has escalated to a major political issue in China. It has been identified that enforcement of environmental regulation is the weakest link in environmental protection. Local government is often the focus of study because of its legal obligation for enforcement under national environmental law, and for its significance in the complex and intriguing central–local relations in the Chinese government system. We propose an interpretative framework to explain the local environmental enforcement dilemma in China, based on an institutional approach. Local governments tend to underperform. We argue that the overall national institutional environment that defines central–local relations in both political and financial terms is key for explaining why local governments fail to meet their obligations. Local governments tend to promote economic growth and maximize tax revenue, by attracting external investment and protecting polluting businesses, at the expense of environmental quality. Inadequate disclosure of environmental data and occasionally intentionally distorting information obstruct public participation and supervision – a key factor for ensuring the accountability of local enforcement. The policy implications of this analysis are that central government, in its capacity as the rule-maker, must take action to adjust the existing central–local relations with respect to the political promotion system and the tax-sharing mechanism. In addition, more stringent procedures and standards must be made by central government regarding the disclosure of environmental data to enable effective public participation. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment

This article reviews recent studies on the politics of climate change in China. We explain the evolution of policy-making and implementation processes and mechanisms over the past two decades, and discuss how they have eventuated in contemporary trends and challenges. Within the unitary hierarchy of the Chinese political system, the central government is responsible for making major policies, and subnational and local governments are responsible for the implementation. The policy-making process is characterized by a consensus building at the center, in contrast to the open public and partisan debate in Western democracies. Climate policy implementation has been based on a so-called ‘target responsibility system’, which disaggregates targets amongst all levels of local governments and related enterprises. While this system has proven effective in achieving the national targets set by the central government, the high costs associated with it have been a source of concern. The key challenge in making and implementing climate policy is to balance economic growth and environmental protection. This challenge is of critical importance in central–local political interactions. Clean energy development has been proposed as a ‘win–win’ solution to help balance economic development and climate change mitigation, and to satisfy both central and local government prerogatives, but the sustainability of such a model is questioned when the global and domestic economy experience difficulties. The central government is trying to translate its consensus in climate change and green development into priorities for local governments through policy pilots and market instruments; the real results will soon be seen. WIREs Clim Change 2013, 4:301–313. doi: 10.1002/wcc.221 This article is categorized under: The Carbon Economy and Climate Mitigation > Policies, Instruments, Lifestyles, Behavior Policy and Governance > National Climate Change Policy

Soil-surface CO2 efflux and its spatial and temporal variations were examined in an 8-y-old ponderosa pine plantation in the Sierra Nevada Mountains in California from June 1998 to August 1999. Continuous measurements of soil CO2 efflux, soil temperatures and moisture were conducted on two 20 3 20 m sampling plots. Microbial biomass, fine root biomass, and the physical and chemical properties of the soil were also measured at each of the 18 sampling locations on the plots. It was found that the mean soil CO2 efflux in the plantation was 4.43 mmol m ‐2 s ‐1 in the growing season and 3.12 mmol m ‐2 s ‐1 in the nongrowing season. These values are in the upper part of the range of published soil-surface CO2 efflux data. The annual maximum and minimum CO2 efflux were 5.87 and 1.67 mmol m ‐2 s ‐1 , respectively, with the maximum occurring between the end of May and early June and the minimum in December. The diurnal fluctuation of CO2 efflux was relatively small ( 14%. Understanding the spatial and temporal variations is essential to accurately assessment of carbon budget at whole ecosystem and landscape scales. Thus, this study bears important implications for the study of large-scale ecosystem dynamics, particularly in response to climatic variations and management regimes.

Effective inhibitors of matrix metalloproteinases (MMPs), a family of connective tissue-degrading enzymes, could be useful for the treatment of diseases such as cancer, multiple sclerosis, and arthritis. Many of the known MMP inhibitors are derived from peptide substrates, with high potency in vitro but little selectivity among MMPs and poor bioavailability. We have discovered nonpeptidic MMP inhibitors with improved properties, and report here the crystal structures of human stromelysin-1 catalytic domain (SCD) complexed with four of these inhibitors. The structures were determined and refined at resolutions ranging from 1.64 to 2.0 A. Each inhibitor binds in the active site of SCD such that a bulky diphenyl piperidine moiety penetrates a deep, predominantly hydrophobic S'1 pocket. The active site structure of the SCD is similar in all four inhibitor complexes, but differs substantially from the peptide hydroxamate complex, which has a smaller side chain bound in the S'1 pocket. The largest differences occur in the loop forming the "top" of this pocket. The occupation of these nonpeptidic inhibitors in the S'1 pocket provides a structural basis to explain their selectivity among MMPs. An analysis of the unique binding mode predicts structural modifications to design improved MMP inhibitors.

Stromelysin, a representative matrix metalloproteinase and target of drug development efforts, plays a prominent role in the pathological proteolysis associated with arthritis and secondarily in that of cancer metastasis and invasion. To provide a structural template to aid the development of therapeutic inhibitors, we have determined a medium-resolution structure of a 20-kDa complex of human stromelysin's catalytic domain with a hydrophobic peptidic inhibitor using multinuclear, multidimensional NMR spectroscopy. This domain of this zinc hydrolase contains a mixed beta-sheet comprising one antiparallel strand and four parallel strands, three helices, and a methionine-containing turn near the catalytic center. The ensemble of 20 structures was calculated using, on average, 8 interresidue NOE restraints per residue for the 166-residue protein fragment complexed with a 4-residue substrate analogue. The mean RMS deviation (RMSD) to the average structure for backbone heavy atoms is 0.91 A and for all heavy atoms is 1.42 A. The structure has good stereochemical properties, including its backbone torsion angles. The beta-sheet and alpha-helices of the catalytic domains of human stromelysin (NMR model) and human fibroblast collagenase (X-ray crystallographic model of Lovejoy B et al., 1994b, Biochemistry 33:8207-8217) superimpose well, having a pairwise RMSD for backbone heavy atoms of 2.28 A when three loop segments are disregarded. The hydroxamate-substituted inhibitor binds across the hydrophobic active site of stromelysin in an extended conformation. The first hydrophobic side chain is deeply buried in the principal S'1 subsite, the second hydrophobic side chain is located on the opposite side of the inhibitor backbone in the hydrophobic S'2 surface subsite, and a third hydrophobic side chain (P'3) lies at the surface.