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941.
942.
Minghua Zhou Bo Zhu Nicolas Brüggemann Jessica Bergmann Yanqiang Wang Klaus Butterbach-Bahl 《Ecosystems》2014,17(2):286-301
Guaranteeing high crop yields while reducing environmental impacts of nitrogen fertilizer use due to associated losses of N2O emissions and nitrate (NO3 ?) leaching is a key challenge in the context of sustainable intensification of crop production. However, few field data sets are available that explore the effect of different forms of N management on yields as well as on N losses in the form of N2O or NO3 ?. Here we report on a large-scale field lysimeter (8 × 4 m2) experiment, which was designed to determine soil CH4 and N2O emissions, NO3 ? leaching losses and crop yields from a subtropical rain-fed wheat–maize rotation in the Sichuan Basin, one of the most intensively used agricultural regions in China. One control and three different fertilizer treatments with the same total rate of N application (280 kg N ha?1 y?1) were included: NF: control (no fertilizer); NPK: synthetic N fertilizer; OMNPK: synthetic N fertilizer plus pig manure; RSDNPK: synthetic N fertilizer plus crop residues. As compared to the standard NPK treatment, annual NO3 ? leaching losses for OMNPK and RSDNPK treatments were decreased by 36 and 22%, respectively (P < 0.05). Similarly, crop yield-scaled NO3 ? leaching for NPK treatment was higher than those for either OMNPK or RSDNPK treatments (P < 0.05). Direct N2O emissions for RSDNPK treatment were decreased as compared with NPK and OMNPK treatments (P < 0.05). Furthermore, the yield-scaled GWP (global warming potential) was lower for the treatments where either pig manure or crop residues were incorporated as compared to the standard NPK treatment (P < 0.05). Our study indicates that it is possible to reduce the negative environmental impact of NO3 ? leaching and N2O emissions without compromising crop productivity. Yield-scaled NO3 ? leaching, similar to the yield-scaled GWP, represents another valuable-integrated metric to address the dual goals of reducing nitrogen pollution and maintaining crop grain yield for a given agricultural system. 相似文献
943.
Philah Lee Subramanian Mohan Raj Shengfang Zhou Somasundar Ashok Selvakumar Edwardraja Sunghoon Park 《Biotechnology and Bioprocess Engineering》2014,19(1):1-7
This study examined the role and physiological relevance of 3-hydroxyisobutyrate dehydrogenase-I (3HIBDHI) of Pseudomonas denitrificans ATCC 13867 in the degradation of 3-hydroxypropionic acid (3-HP) during 3-HP production. The gene encoding 3HIBDH-I of P. denitrificans ATCC 13867 was cloned and expressed in Escherichia coli BL21 (DE3). The recombinant 3HIBDH-I was then purified on a Ni-NTA-HP column and characterized for its choice of substrates, cofactors, metals, reductants, and the optimal temperature and pH. The recombinant 3HIBDH-I showed a high catalytic constant (k cat/K m) of 604.1 ± 71.1 mM/S on (S)-3-hydroxyisobutyrate, but no detectable activity on (R)-3-hydroxyisobutyrate. 3HIBDH-I preferred NAD+ over NADP+ as a cofactor for its catalytic activity. The k cat/K m determined for 3-HP was 15.40 ± 1.43 mM/S in the presence of NAD+ at 37°C and pH 9.0. In addition to (S)-3-hydroxyisobutyrate and 3-HP, 3HIBDH-I utilized l-serine, methyl-d,l-serine, and methyl-(S)-(+)-3-hydroxy-2-methylpropionate; on the other hand, the k cat/K m values determined for these substrates were less than 5.0mM/S. Ethylenediaminetetraacetic acid, 2-mercaptoethanol, dithiothreitol and Mn2+ increased the activity of 3HIBDHI significantly, whereas the presence of Fe2+, Hg2+ and Ag+ in the reaction mixture at 1.0 mM completely inhibited its activity. This study revealed the characteristics of 3HIBDH-I and its significance in 3-HP degradation. 相似文献
944.
Pingping Zhu Lixuan Zhan Tingna Zhu Donghai Liang Jiaoyue Hu Weiwen Sun Qinghua Hou Huarong Zhou Baoxing Wu Yanmei Wang En Xu 《Molecular neurobiology》2014,49(3):1338-1349
Postconditioning has regenerated interest as a mechanical intervention against cerebral ischemia/reperfusion injury, but its molecular mechanisms remain unknown. We previously reported that hypoxic postconditioning (HPC) ameliorated neuronal death induced by transient global cerebral ischemia (tGCI) in hippocampal CA1 subregion of adult rats. This study tested the hypothesis that p38-mitogen-activated protein kinase (p38 MAPK)/mitogen- and stress-response kinase 1 (MSK1) signaling pathway plays a role in the HPC-induced neuroprotection. Male Wistar rats were subjected to 10 min ischemia induced by applying the four-vessel occlusion method. HPC with 120 min was applied at 24 h after reperfusion. Immunohistochemistry and Western blot were used to detect the expression of phosphorylation of p38 MAPK and MSK1, as well as cleaved caspase-3. We found that HPC induced a significant increase of phosphorylated p38 MAPK and MSK1 in neurons of hippocampal CA1 region and a significant decrease in glial cells after tGCI as well. Furthermore, HPC attenuated caspase-3 cleavation triggered by tGCI in CA1 region. Moreover, p38 MAPK inhibition by SB203580 significantly decreased the phosphorylation of MSK1, increased cleaved caspase-3 expression, and abolished the neuroprotection of HPC. These findings suggested that p38 MAPK/MSK1 signaling axis contributed to HPC-mediated neuroprotection against tGCI, at least in part, by regulating the activation of caspase-3. 相似文献
945.
凤仙花属(Impatiens)植物具有极为广泛的多样性和类型各异的特化传粉者, 被誉为“双子叶的兰花”, 受到众多传粉生物学家的关注。本文以海南特有种海南凤仙花(Impatiens hainanensis)为研究对象, 对3个不同海拔梯度的种群进行了开花生物学特性和开花物候、花器官结构、花粉活力和柱头活性、传粉者种类和访花行为及繁育系统的比较研究。结果表明: 单花花期4.10 ± 0.46 d, 雄性期和雌性期分别约为3.15 ± 0.24 d和0.95 ± 0.36 d; 种群开花峰期在8月初, 高海拔种群的花期高峰相对滞后。低、中海拔种群花粉活力呈现先升高后下降的趋势, 以开花第2 d花粉活力最高; 高海拔种群花粉活力随开花时间推移逐渐下降; 柱头活性随开花时间的推移而增强, 高海拔种群开花各天次均较低、中海拔种群低。主要传粉昆虫为黄黑无垫蜂(Amegilla leptocoma)和绿条无垫蜂(A. zonata), 低、中海拔种群以黄黑无垫蜂为主, 高海拔种群以绿条无垫蜂为主。未观察到自动自花授粉和无融合生殖现象, 人工授粉能明显增加坐果率(75-90%), 自然坐果率在高海拔种群相对较低(40-60%), 说明存在较强的传粉者限制。海南凤仙花的保护需要同时关注其有效传粉者的保护, 促进有效传粉昆虫在不同海拔种群之间的往来, 保证种群间的花粉流与种子流, 维持海南凤仙花的种群遗传多样性与有效种群大小。 相似文献
946.
Xinglei Yao Na Zhou Li Wan Xiaodong Su Zhao Sun Hiroyuki Mizuguchi Yasuo Yoshioka Shinsaku Nakagawa Robert Chunhua Zhao Jian-Qing Gao 《Biochemical and biophysical research communications》2014
Mesenchymal stem cells (MSCs) are non-hematopoietic cells with multi-lineage potential, which makes them attractive targets for regenerative medicine applications. Efficient gene transfer into MSCs is essential for basic research in developmental biology and for therapeutic applications involving gene-modification in regenerative medicine. Adenovirus vectors (Advs) can efficiently and transiently introduce an exogenous gene into many cell types via their primary receptors, the coxsackievirus and adenovirus receptors (CARs), but not into MSCs, which lack CAR expression. To overcome this problem, an Adv coated with cationic polymer polyethyleneimine (PEI) was developed. In this study, we demonstrated that PEI coating with an optimal ratio can enhance adenoviral transduction of MSCs without cytotoxicity. We also investigated the physicochemical properties and internalization mechanisms of the PEI-coated Adv. These results could help to evaluate the potentiality of the PEI-coated Adv as a prototype vector for efficient and safe transduction into MSCs. 相似文献
947.
Jin-Yong Hu Yue Zhou Fei He Xue Dong Liang-Yu Liu George Coupland Franziska Turck Juliette de Meaux 《The Plant cell》2014,26(5):2024-2037
The timing of flowering is pivotal for maximizing reproductive success under fluctuating environmental conditions. Flowering time is tightly controlled by complex genetic networks that integrate endogenous and exogenous cues, such as light, temperature, photoperiod, and hormones. Here, we show that AGAMOUS-LIKE16 (AGL16) and its negative regulator microRNA824 (miR824) control flowering time in Arabidopsis thaliana. Knockout of AGL16 effectively accelerates flowering in nonvernalized Col-FRI, in which the floral inhibitor FLOWERING LOCUS C (FLC) is strongly expressed, but shows no effect if plants are vernalized or grown in short days. Alteration of AGL16 expression levels by manipulating miR824 abundance influences the timing of flowering quantitatively, depending on the expression level and number of functional FLC alleles. The effect of AGL16 is fully dependent on the presence of FLOWERING LOCUS T (FT). Further experiments show that AGL16 can interact directly with SHORT VEGETATIVE PHASE and indirectly with FLC, two proteins that form a complex to repress expression of FT. Our data reveal that miR824 and AGL16 modulate the extent of flowering time repression in a long-day photoperiod. 相似文献
948.
949.
Henan Li Chunjiang Zhao Hongbin Chen Feifei Zhang Wenqiang He Xiaojuan Wang Qi Wang Ruifu Yang Dongsheng Zhou Hui Wang 《PloS one》2013,8(1)
A comparative genomic microarray comprising 2,457 genes from two whole genomes of S. aureus was employed for the comparative genome hybridization analysis of 50 strains of divergent clonal lineages, including methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), and swine strains in China. Large-scale validation was confirmed via polymerase chain reaction in 160 representative clinical strains. All of the 50 strains were clustered into seven different complexes by phylogenetic tree analysis. Thirteen gene clusters were specific to different S. aureus clones. Ten gene clusters, including seven known (vSa3, vSa4, vSaα, vSaβ, Tn5801, and phage ϕSa3) and three novel (C8, C9, and C10) gene clusters, were specific to human MRSA. Notably, two global regulators, sarH2 and sarH3, at cluster C9 were specific to human MRSA, and plasmid pUB110 at cluster C10 was specific to swine MRSA. Three clusters known to be part of SCCmec, vSa4 or Tn5801, and vSaα as well as one novel gene cluster C12 with homology with Tn554 of S. epidermidis were identified as MRSA-specific gene clusters. The replacement of ST239-spa t037 with ST239-spa t030 in Beijing may be a result of its acquisition of vSa4, phage ϕSa1, and ϕSa3. In summary, thirteen critical gene clusters were identified to be contributors to the evolution of host specificity and antibiotic resistance in Chinese S. aureus. 相似文献
950.
Di Zhang Yamin Li Liang Xu Maosheng Cheng Ying Zhou Junlin He 《Nucleosides, nucleotides & nucleic acids》2013,32(10):734-747
Tert-butyldiphenylsilyl (TBDPS) was testified to be an appropriate orthogonal protecting group for novel 7-hydroxyl-functionalized 8-aza-7-deaza-2′-deoxyadenosine analogues. It was stable in partial and complete hydrogenation reactions used for the different linker preparation. The corresponding phosphoramidites and hydroxyl-functionalized oligodeoxynucleotides were synthesized and identified. The thermal effect of the hydroxyl group with different linkers on DNA duplexes was evaluated. It provided a feasible strategy for the preparation of hydroxyl-functionalized DNAs for the nucleic acid research. 相似文献