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Now showing items 17 - 32 of 56

  • Effects of different drying methods on the grinding characteristics of Ximeng lignite

    Zhu, Jie-Feng   Liu, Jian-Zhong   Wu, Jun-Hong   Cheng, Jun   Wang, Zhi-Hua   Zhou, Jun-Hu   Cen, Ke-Fa  

    Ximeng lignite (XL) was treated by using different drying methods, namely, conventional, microwave, and combination, to investigate their effects on the grinding characteristics of XL. The controlled mechanisms that improved the grindability of XL treated by different drying methods were analyzed with proximate analysis and scanning electron microscope. Results showed that the removal moisture and the physical structure damage induced by thermal stress or steam jet flow improved the grindability of treated XL. Microwave drying had the most remarkable effect on the grindability of XL. The increments in grindability of XL irradiated for 0.5 and 3 min were 44.03% and 200.45%, respectively. Compared with conventional dying, combined drying simultaneously improved grindability of XL, and reduced energy consumption. However, combined drying reduced the effects of microwave drying on the increment in the grindability of XL. Drying treatment for a short period could not effectively increase the mass fraction of finely ground product unless drying time was properly prolonged. According to the economy evaluation at lab scale, treatment of XL by microwave drying for a short period improved the grindability of treated XL and achieved a maximum energy saving of around 10% after a long period of the grinding process. (C) 2015 Elsevier Ltd. All rights reserved.
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  • Loss of GSNOR1 Function Leads to Compromised Auxin Signaling and Polar Auxin Transport.

    Shi, Ya-Fei   Wang, Da-Li   Wang, Chao   Culler, Angela Hendrickson   Kreiser, Molly A   Suresh, Jayanti   Cohen, Jerry D   Pan, Jianwei   Baker, Barbara   Liu, Jian-Zhong  

    Cross talk between phytohormones, nitric oxide (NO), and auxin has been implicated in the control of plant growth and development. Two recent reports indicate that NO promoted auxin signaling but inhibited auxin transport probably through S-nitrosylation. However, genetic evidence for the effect of S-nitrosylation on auxin physiology has been lacking. In this study, we used a genetic approach to understand the broader role of S-nitrosylation in auxin physiology in Arabidopsis. We compared auxin signaling and transport in Col-0 and gsnor1-3, a loss-of-function GSNOR1 mutant defective in protein de-nitrosylation. Our results showed that auxin signaling was impaired in the gsnor1-3 mutant as revealed by significantly reduced DR5-GUS/DR5-GFP accumulation and compromised degradation of AXR3NT-GUS, a useful reporter in interrogating auxin-mediated degradation of Aux/IAA by auxin receptors. In addition, polar auxin transport was compromised in gsnor1-3, which was correlated with universally reduced levels of PIN or GFP-PIN proteins in the roots of the mutant in a manner independent of transcriptionand 26S proteasome degradation. Our results suggest that S-nitrosylation and GSNOR1-mediated de-nitrosylation contribute to auxin physiology, and impaired auxin signaling and compromised auxin transport are responsible for the auxin-related morphological phenotypes displayed by the gsnor1-3 mutant. Copyright =C2=A9 2015 The Author. Published by Elsevier Inc. All rights reserved.
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  • Gaining insight into soybean defense responses using functional genomics approaches: Figure 1

    Liu, Jian-Zhong   Graham, Michelle A.   Pedley, Kerry F.   Whitham, Steven A.  

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  • Production of L-ornithine from sucrose and molasses by recombinant Corynebacterium glutamicum

    Zhang, Yuan-Yuan   Bu, Yi-Fan   Liu, Jian-Zhong  

    Sucrose and molasses are attractive raw materials for industrial fermentation. Although Corynebacterium glutamicum shows sucrose-utilizing activity, sucrose or molasses is only a fraction of carbon source used in the fermentation medium in most works. An engineered C. glutamicum strain was constructed for producing L-ornithine with sucrose or molasses as a sole carbon source by transferring Mannheimia succiniciproducens beta-fructofuranosidase gene (sacC). The engineered strain, C. glutamicum Delta APE6937R42 (pEC-sacC), produced 22.0 g/L of L-ornithine with sucrose as the sole carbon source, which is on par with that obtained by the parent strain C. glutamicum Delta APE6937R42 with glucose as the sole carbon. The resulting strain C. glutamicum Delta APE6937R42 (pEC-sacC) produced 27.0 g/L of L-ornithine with molasses as the sole carbon source, which is higher than that obtained by the parent strain C. glutamicum Delta APE6937R42 with glucose as the sole carbon. This strategy can be applied for developing sucrose- or molasses-utilizing industrial strains.
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  • Ectopic expression of Arabidopsis glutaredoxin AtGRXS17 enhances thermotolerance in tomato.

    Wu, Qingyu   Lin, Julie   Liu, Jian-Zhong   Wang, Xiaofei   Lim, Wansang   Oh, Myungmin   Park, Jungeun   Rajashekar, C B   Whitham, Steven A   Cheng, Ning-Hui   Hirschi, Kendal D   Park, Sunghun  

    While various signalling networks regulate plant responses to heat stress, the mechanisms regulating and unifying these diverse biological processes are largely unknown. Our previous studies indicate that the Arabidopsis monothiol glutaredoxin, AtGRXS17, is crucial for temperature-dependent postembryonic growth in Arabidopsis. In the present study, we further demonstrate that AtGRXS17 has conserved functions in anti-oxidative stress and thermotolerance in both yeast and plants. In yeast, AtGRXS17 co-localized with yeast ScGrx3 in the nucleus and suppressed the sensitivity of yeast grx3grx4 double-mutant cells to oxidative stress and heat shock. In plants, GFP-AtGRXS17 fusion proteins initially localized in the cytoplasm and the nuclear envelope but migrated to the nucleus during heat stress. Ectopic expression of AtGRXS17 in tomato plants minimized photo-oxidation of chlorophyll and reduced oxidative damage of cell membrane systems under heat stress. This enhanced thermotolerance correlated with increased catalase (CAT) enzyme activity and reduced H=E2=82=82O=E2=82=82 accumulation in AtGRXS17-expressing tomatoes. Furthermore, during heat stress, expression of the heat shock transcription factor (HSF) and heat shock protein (HSP) genes was up-regulated in AtGRXS17-expressing transgenic plants compared with wild-type controls. Thus, these findings suggest a specific protective role of a redox protein against temperature stress and provide a genetic engineering strategy to improve crop thermotolerance. =C2=A9 2012 The Authors. Plant Biotechnology Journal =C2=A9 2012 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.
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  • Effects of temperature on fertilized eggs and larvae of tawny puffer Takifugu flavidus

    Zhang, Gen-Yu   Zhu, Ya-Zhu   Liu, Jian-Zhong   Zang, Wei-Ling  

    Tawny puffer Takifugu flavidus is a species found in China considered to have potential for aquaculture. Experiments were conducted to determine the optimal temperature for its incubation and larval culture. Fertilized eggs collected from cultured broodstocks that were induced to ovulate with a [D-Ala(6)-Pro(9)-Net]-luteinizing hormone-releasing hormone analogue were inseminated. The effect of temperature (19, 20, 23, 26 and 29 degrees C) on the hatch rate, incubation period, viability of 24 h post-hatch larvae and total mortality rate was assessed. The effect of temperature (20, 23, 26 and 29 degrees C) on the growth and survival of larvae from 3 to 19 days after hatching (dah) was also assessed. The results showed that the optimal temperature for successful development of fertilized eggs ranged from 23 to 26 degrees C, and the highest hatch rate, the optimal viability of 24 h post-hatch larvae and the lowest total mortality rate were all predicted using quadratic equations. The relationship between temperature and the incubation period of tawny puffer eggs was determined using the effective degree-day model. The temperature at developmental zero (t(0)) was 11.34 degrees C, and the sum of effective degree-days (k) was 52.356. The survival rate of tawny puffer larvae at 20 degrees C was significantly lower than among 23, 26 and 29 degrees C, whereas the survival rate was not significantly different from that at 23,26 and 29 degrees C. The larval growth rate increased rapidly as the temperature increased, showing a linear relationship in the range of temperatures investigated. The optimal temperature for larval culture ranged from 23 to 29 degrees C.
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  • 9,9-Dibenzyl-10-trimethylsilyl-9,10-dihydroanthracene

    Liu, Jian-Zhong   Dhar, Raj K.   Fronczek, Frank R.   Rabideau, Peter W.   Watkins, Steven F.  

    The title compound, C31H32Si or (C6H5CH2)(2)C14H9Si(CH3)(3), has a concave dihydroanthracene unit. The central ring adopts a half-chair conformation and the two benzene rings are tilted by 14.40 (7)degrees with respect to one another. The trimethylsilyl group is substituted in the axial position of the half-chair.
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  • S-nitrosylation inhibits the kinase activity of tomato phosphoinositide-dependent kinase 1 (PDK1)

    Liu, Jian-Zhong   Duan, Jicheng   Ni, Min   Liu, Zhen   Qiu, Wen-Li   Whitham, Steven A.   Qian, Wei-Jun  

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  • Enhanced Astaxanthin Production in Escherichia coli via Morphology and Oxidative Stress Engineering.

    Lu, Qian   Liu, Jian-Zhong  

    Astaxanthin is a carotenoid of high commercial value because of its excellent antioxidative, anti-inflammatory, and anticancer properties. Here, we developed a novel strategy for improving the production of astaxanthin via morphology and oxidative stress engineering. First, we identified the morphology-/membrane- and oxidative stress-related genes, which should be knocked down, using the CRISPRi system. Deleting the morphology-/membrane-related genes (lpp and bamB) and the oxidative stress-related genes (uspE and yggE) generated longer and larger cells with higher reactive oxygen species (ROS) levels, thus enhancing the production of astaxanthin and decreasing cell growth. To not only improve cell growth but also obtain longer and larger cells with higher ROS levels, a complementary expression system using a temperature-sensitive plasmid was established. Complementarily expressing the morphology-/membrane-related genes (lpp and bamB) and the oxidative stress-related genes (uspE and yggE) further improved the production of astaxanthin to 11.92 mg/g dry cell weight in shake flask cultures.=20
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  • A mathematical model for gluconic acid fermentation by Aspergillus niger

    Liu, Jian-Zhong   Weng, Li-Ping   Zhang, Qian-Ling   Xu, Hong   Ji, Liang-Nian  

    The fermentation kinetics of gluconic acid by Aspergillus niger were studied in a batch system. A simple model was proposed using the logistic equation for growth, the Luedeking–Piret equation for gluconic acid production and Luedeking–Piret-like equation for glucose consumption. The model appeared to provide a reasonable description for each parameter during the growth phase. The production of gluconic acid was growth-associated.
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  • Enhanced dye decolorization efficiency by citraconic anhydride-modified horseradish peroxidase

    Liu, Jian-Zhong   Wang, Teng-Li   Ji, Liang-Nian  

    Bromophenol blue and methyl orange removal capabilities of citraconic anhydride-modified horseradish peroxidase were compared with those of native horseradish peroxidase. Citraconic anhydride-modified horseradish peroxidase showed higher decolorization efficiencies for both dyes than native horseradish peroxidase. Upon the chemical modification, the decolorization efficiencies were increased by 1.8 % and 12.4% for bromophenol blue and methyl orange, respectively. The quantitative relationships between decolorization efficiencies of dyes and reaction conditions were also investigated. Experimental data revealed that aqueous phase pH, reaction time, temperature, enzyme concentration and ratio of dye and H2O2 play a significant role on the dye degradation. Lower dose of citraconic anhydride-modified horseradish peroxidase was required than that of native enzyme for the decolorizations of both dyes to obtain the same decolorization efficiencies. Citraconic anhydride-modified HRP exhibited a good decolorization of dye over a wide range of dye concentration from 8 to 24 or 32 mu mol l(-1) at 300 mu mol l(-1) H2O2, which would match industrial expectations. Kinetic constants for two different dyes were also determined. Citraconic anhydride-modified horseradish peroxidase shows greater affinity and catalytic efficiency than native horseradish peroxidase for both dyes. (c) 2006 Elsevier B.V. All rights reserved.
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  • APPswe/A beta Regulation of Osteoclast Activation and RAGE Expression in an Age-Dependent Manner

    Cui, Shun   Xiong, Fei   Hong, Yan   Jung, Ji-Ung   Li, Xing-Sheng   Liu, Jian-Zhong   Yan, Riqiang   Mei, Lin   Feng, Xu  

    Alzheimer's disease (AD), one of the most dreaded neurodegenerative disorders, is characterized by cortical and cerebrovascular amyloid beta peptide (A beta) deposits, neurofibrillary tangles, chronic inflammation, and neuronal loss. Increased bone fracture rates and reduced bone density are commonly observed in patients with AD, suggesting one or more common denominators between both disorders. However, very few studies are available that have addressed this issue. Here, we present evidence for a function of amyloid precursor protein (APP) and A beta in regulating osteoclast (OC) differentiation in vitro and in vivo. Tg2576 mice, which express the Swedish mutation of APP (APPswe) under the control of a prion promoter,((1,2)) exhibit biphasic effects on OC activation, with an increase of OCs in younger mice (< 4 months old), but a decrease in older Tg2576 mice (> 4 months old). The increase of OCs in young Tg2576 mice appears to be mediated by A beta oligomers and receptor for advanced glycation end products (RAGE) expression in bone marrow macrophages (BMMs). However, the decrease of OC formation and activity in older Tg2576 mice may be due to the increase of soluble rage (sRAGE) in aged Tg2576 mice, an inhibitor of RANKL-induced osteoclastogenesis. These results suggest an unexpected function of APPswe/A beta, reveal a mechanism underlying altered bone remodeling in AD patients, and implicate APP/A beta and RAGE as common denominators for both AD and osteoporosis. (C) 2011 American Society for Bone and Mineral Research.
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  • Pyrolysis characteristics of low-rank coals based on double-gaussian distributed activation energy model

    Liu, Jian-Zhong   Yang, Yu-Meng   Wang, Zhihua   Cen, Kefa  

    Pyrolysis is an important technology in the utilization of low-rank coals (LRCs) and is a prerequisite stage for other conversion methods. This study aimed to develop an understanding of the pyrolysis process of LRCs, especially the relationship between the pyrolysis kinetics and the internal chemical structure. The chemical structure parameters of all of the samples were obtained using the Fourier transform infrared spectroscopy (FTIR) method. Thermogravimetric (TG) experiments were conducted at different heating rates (5, 10, and 20 K/min), and the experimental results were fitted using the distributed activation energy model (DAEM). DAEM based on double-Gaussian distribution (2G-DAEM) exhibited an acceptable fit to the experimental data in this study. An analysis of the chemical structure parameters of the four types of coals and the kinetic model obtained by fitting indicated that the difference in the chemical structure parameters among the coal samples could effectively explain the difference in the pyrolysis process and the activation energy distribution. The primary pyrolysis stage of the coal samples, including the thermal hysteresis effect caused by the increase in the heating rate, was accurately described by the 2G-DAEM in this study.
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  • WITHDRAWN: A mathematical model for gluconic acid fermentation by Aspergillus niger

    Liu, Jian-Zhong   Weng, Li-Ping   Zhang, Qian-Ling   Xu, Hong   Ji, Liang-Nian  

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  • Metabolic evolution and a comparative omics analysis of Corynebacterium glutamicum for putrescine production.

    Li, Zhen   Shen, Yu-Ping   Jiang, Xuan-Long   Feng, Li-Shen   Liu, Jian-Zhong  

    Putrescine is widely used in the industrial production of bioplastics, pharmaceuticals, agrochemicals, and surfactants. Because the highest titer of putrescine is much lower than that of its precursor L-ornithine reported in microorganisms to date, further work is needed to increase putrescine production in Corynebacterium glutamicum. We first compared 7 ornithine decarboxylase genes and found that the Enterobacter cloacae ornithine decarboxylase gene speC1 was most suitable for putrescine production in C. glutamicum. Increasing NADPH availability and blocking putrescine oxidation and acetylation were chosen as targets for metabolic engineering. The putrescine producer C. glutamicum PUT4 was first constructed by deleting puo, butA and snaA genes, and replacing the fabG gene with E. cloacae speC1. After adaptive evolution with C. glutamicum PUT4, the evolved strain C. glutamicum PUT-ALE, which produced an 96% higher amount of putrescine compared to the parent strain, was obtained. The whole genome resequencing indicates that the SNPs located in the odhA coding region may be associated with putrescine production. The comparative proteomic analysis reveals that the pentose phosphate and anaplerotic pathway, the glyoxylate cycle, and the ornithine biosynthetic pathway were upregulated in the evolved strain C. glutamicum PUT-ALE. The aspartate family, aromatic, and branched chain amino acid and fatty acid biosynthetic pathways were also observed to be downregulated in C. glutamicum PUT-ALE. Reducing OdhA activity by replacing the odhA native start codon GTG with TTG and overexpression of cgmA or pyc458 further improved putrescine production. Repressing the carB, ilvH, ilvB and aroE expression via CRISPRi also increased putrescine production by 5, 9, 16 and 19%, respectively.=20
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  • Soybean Homologs of MPK4 Negatively Regulate Defense Responses and Positively Regulate Growth and Development

    Liu, Jian-Zhong   Horstman, Heidi D.   Braun, Edward   Graham, Michelle A.   Zhang, Chunquan   Navarre, Duroy   Qiu, Wen-Li   Lee, Yeunsook   Nettleton, Dan   Hill, John H.  

    Mitogen-activated protein kinase (MAPK) cascades play important roles in disease resistance in model plant species such as Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum). However, the importance of MAPK signaling pathways in the disease resistance of crops is still largely uninvestigated. To better understand the role of MAPK signaling pathways in disease resistance in soybean (Glycine max), 13, nine, and 10 genes encoding distinct MAPKs, MAPKKs, and MAPKKKs, respectively, were silenced using virus-induced gene silencing mediated by Bean pod mottle virus. Among the plants silenced for various MAPKs, MAPKKs, and MAPKKKs, those in which GmMAPK4 homologs (GmMPK4s) were silenced displayed strong phenotypes including stunted stature and spontaneous cell death on the leaves and stems, the characteristic hallmarks of activated defense responses. Microarray analysis showed that genes involved in defense responses, such as those in salicylic acid (SA) signaling pathways, were significantly up-regulated in GmMPK4-silenced plants, whereas genes involved in growth and development, such as those in auxin signaling pathways and in cell cycle and proliferation, were significantly down-regulated. As expected, SA and hydrogen peroxide accumulation was significantly increased in GmMPK4-silenced plants. Accordingly, GmMPK4-silenced plants were more resistant to downy mildew and Soybean mosaic virus compared with vector control plants. Using bimolecular fluorescence complementation analysis and in vitro kinase assays, we determined that GmMKK1 and GmMKK2 might function upstream of GmMPK4. Taken together, our results indicate that GmMPK4s negatively regulate SA accumulation and defense response but positively regulate plant growth and development, and their functions are conserved across plant species.
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