Yurong Bi

Lanzhou University, Kao-lan-hsien, Gansu Sheng, China

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Publications (58)147.96 Total impact

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    ABSTRACT: Silicon induces cell death when ethylene is suppressed in cultured tobacco BY-2 cells. There is a crosstalk between Si and ethylene signaling. Silicon (Si) is beneficial for plant growth. It alleviates both biotic and abiotic stresses in plants. How Si works in plants is still mysterious. This study investigates the mechanism of Si-induced cell death in tobacco BY-2 cell cultures when ethylene is suppressed. Results showed that K2SiO3 alleviated the damage of NaCl stress. Si treatment rapidly increased ethylene emission and the expression of ethylene biosynthesis genes. Treatments with Si + Ag and Si + aminooxyacetic acid (AOA, ethylene biosynthesis inhibitor) reduced the cell growth and increased cell damage. The treatment with Si + Ag induced hydrogen peroxide (H2O2) generation and ultimately cell death. Some nucleus of BY-2 cells treated with Si + Ag appeared TUNEL positive. The inhibition of H2O2 and nitric oxide (NO) production reduced the cell death rate induced by Si + Ag treatment. Si eliminated the up-regulation of alternative pathway by Ag. These data suggest that ethylene plays an important role in Si function in plants. Without ethylene, Si not only failed to enhance plant resistance, but also elevated H2O2 generation and further induced cell death in tobacco BY-2 cells.
    Plant Cell Reports 12/2014; · 2.94 Impact Factor
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    ABSTRACT: The second messenger cyclic guanosine 3',5'-monophosphate (cGMP) plays an important role in plant development and responses to stress. Recent studies indicated that cGMP is a secondary signal generated in response to auxin stimulation. cGMP also mediates auxin-induced adventitious root formation in mung bean and gravitropic bending in soybean. Nonetheless, the mechanism of the participation of cGMP in auxin signalling to affect these growth and developmental processes is largely unknown. In this report we provide evidence that indole-3-acetic acid (IAA) induces cGMP accumulation in Arabidopsis roots through modulation of the guanylate cyclase activity. Application of 8-bromo-cGMP (a cell-permeable cGMP derivative) increases auxin-dependent lateral root formation, root hair development, primary root growth, and gene expression. In contrast, inhibitors of endogenous cGMP synthesis block these processes induced by auxin. Data also showed that 8-bromo-cGMP enhances auxin-induced degradation of Aux/IAA protein modulated by the SCF(TIR1) ubiquitin-proteasome pathway. Furthermore, it was found that 8-bromo-cGMP is unable to directly influence the auxin-dependent TIR1-Aux/IAA interaction as evidenced by pull-down and yeast two-hybrid assays. In addition, we provide evidence for cGMP-mediated modulation of auxin signalling through cGMP-dependent protein kinase (PKG). Our results suggest that cGMP acts as a mediator to participate in auxin signalling and may govern this process by PKG activity via its influence on auxin-regulated gene expression and auxin/IAA degradation.
    Journal of Experimental Botany 03/2014; · 5.79 Impact Factor
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    ABSTRACT: Narciclasine (NCS) is an Amaryllidaceae alkaloid isolated from Narcissus tazetta bulbs. Its phytotoxic effects on plant growth were examined in lettuce (Lactuca sativa L.) seedlings. Results showed that high concentrations (0.5-5 μM) of NCS restricted the growth of lettuce roots in a dose-dependent manner. In NCS-treated lettuce seedlings, the following changes were detected: reduction of mitotic cells and cell elongation in the mature region, inhibition of proliferation of meristematic cells, and cell cycle. Moreover, comet assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay indicated that higher levels NCS (0.5-5 μM) induced DNA damage in root cells of lettuce. The decrease in meristematic cells and increase in DNA damage signals in lettuce roots in responses to NCS are in a dose-dependent manner. NCS-induced reactive oxygen species accumulation may explain an increase in DNA damage in lettuce roots. Thus, the restraint of root growth is due to cell cycle arrest which is caused by NCS-induced DNA damage. In addition, it was also found that NCS (0.5-5 μM) inhibited the root hair development of lettuce seedlings. Further investigations on the underlying mechanism revealed that both auxin and ethylene signaling pathways are involved in the response of root hairs to NCS.
    Protoplasma 01/2014; · 3.17 Impact Factor
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    ABSTRACT: Corneal (lymph) angiogenesis is a predominant risk-factor for immune rejection after transplantation. Techniques to regress pre-existing pathological corneal lymphatic vessels prior to transplantation are missing so far. Therefore we analysed the possibility to regress corneal lymphatic vessels by photodynamic therapy (PDT), after intrastromal verteporfin injection. Combined hemangiogenesis and lymphangiogenesis was induced in female BALB/c mice using the murine model of suture-induced inflammatory neovascularisation. Thereafter, the treatment group received an intrastromal injection of verteporfin (controls: phosphate buffered saline (PBS)) followed by PDT. Corneas were excised at different time points (1 day, 5 days and 10 days) after PDT and corneal whole mounts were stained with CD31 and LYVE-1 to quantify hemangiogenesis and lymphangiogenesis. Whereas blood vessels showed no significant reduction after PDT, lymphatic vessels could significantly be reduced with PDT after intrastromal verteporfin injection: 1 day after PDT, lymphatic vessels were reduced by 62% (p=0.20). After 5 days and 10 days, lymphatic vessels were reduced by 51% and 48% (p<0.001), respectively. This study for the first time shows that PDT after corneal intrastromal verteporfin injection can selectively regress lymphatic vessels. This may become a new 'preconditioning strategy' to reduce pre-existing corneal lymphatic vessels prior to transplantation and thereby reduce allograft rejection in high-risk patients.
    The British journal of ophthalmology 01/2014; · 2.92 Impact Factor
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    ABSTRACT: The FY3 GNOS (GNSS Occultation Sounder) mission is a GNSS (Global Navigation Satellite System) radio occultation mission of China for remote sensing of Earth's neutral atmosphere and the ionosphere. GNOS will use both the Global Positioning System (GPS) and the Beidou navigation satellite systems on the China Feng-Yun-3 (FY3) series satellites. The first FY3-C was launched at 03:03 UTC, 23 September 2013. GNOS was developed by Center for Space Science and Applied Research, Chinese Academy of Sciences (CSSAR). It will provide vertical profiles of atmospheric temperature, pressure, and humidity, as well as ionospheric electron density profiles on a global basis. These data will be used for numerical weather prediction, climate research, and ionospheric research and space weather. This paper describes the FY3 GNOS mission and the GNOS instrument characteristics. It presents simulation results of the number and distribution of GNOS occultation events with the Regional Beidou constellation and the full GPS constellation, under the limitation of the GNOS instrument occultation channel number. This paper presents the instrument performance as derived from analysis of measurement data in laboratory and mountain-based occultation validation experiments at Mt. Wuling in Hebei Province. The mountain-based GNSS occultation validation tests show that GNOS can acquire or track lower elevation radio signal for rising or setting occultation events. The refractivity profiles of GNOS obtained during the mountain-based experiment were compared with those from radiosondes. The results show that the refractivity profiles obtained by GNOS are consistent with those from the radiosonde. The RMS of the differences between the GNOS and radiosonde refractivities is less than 3%.
    12/2013; 7(1).
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    ABSTRACT: PurposeTo evaluate the efficacy of two-step retrograde closed stenting for treating canalicular laceration.Methods Forty-eight consecutive canalicular laceration cases (48 eyes) were randomised and divided into two groups: a one-step group and a two-step group. In the two-step group (23 cases), the first step was performed in the outpatient department and included identifying the medial cut end of the canaliculus and probing under a slit-lamp microscope, followed by a retrograde canalicular stenting assisted by a memory titanium stylet. The second step was canalicular anastomosis, which was performed in the operating room. In the one-step group (25 cases), all of the surgical procedures were performed when preoperative preparations were simultaneously available.ResultsThe time elapsed from the doctor visit to the treatment was 4.3±2.4 h in the two-step group and 18.8±6.3 h in the one-step group (P<0.01). The canalicular medial cut ends were found in all cases, but 8.6±3.5 min was needed in the two-step group, and 51.4±24.2 min was needed in the one-step group (P<0.01). The numerical rating scale for pain during surgery was 1.8±1.2 in the two-step group and 5.4±2.2 in the one-step group (P<0.01). One case (2.63%) in the two-step group and nine cases (36%) in the one-step group required other assisted methods to locate the medial cut end (P=0.007). Twenty-one cases (91.3%) in the two-step group and 20 cases (80%) in the one-step group achieved patent lacrimal drainage systems during a 12-month follow-up (P=0.528).Conclusions The two-step canalicular anastomosis method allows an early search for the medial cut end of the canaliculus and improves the chances of finding it; it is also a quicker, less invasive method for treating canalicular lacerations.Eye advance online publication, 23 August 2013; doi:10.1038/eye.2013.169.
    Eye (London, England) 08/2013; · 1.97 Impact Factor
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    ABSTRACT: KEY MESSAGE : The major insight in this manuscript is that we identified a new flowering regulator, GmSOC1-like, which may participate in the initiation and maintenance of flowering in soybean. Flowering is pivotal for the reproductive behavior of plants, and it is regulated by complex and coordinated genetic networks that are fine-tuned by endogenous cues and environmental signals. To better understand the molecular basis of flowering regulation in soybean, we isolated GmSOC1 and GmSOC1-like, two putative soybean orthologs for the Arabidopsis SUPPRESSOR OF OVEREXPRESSION OF CO1/AGAMOUS-LIKE 20 (SOC1/AGL20). The expression pattern of GmSOC1-like was analyzed by qRT-PCR in Zigongdongdou, a photoperiod-sensitive soybean cultivar. GmSOC1-like was widely expressed at different levels in most organs of the soybean, with the highest expression in the shoot apex during the early stage of floral transition. In addition, its expression showed a circadian rhythm pattern, with the highest expression at midnight under short-day (SD) condition. Intriguingly, GmSOC1-like was induced 4 days earlier than GmSOC1 during flowering transition in SD, suggesting that GmSOC1 and GmSOC1-like expression might be differentially regulated. However, under long-day (LD) condition, the expression of GmSOC1 and GmSOC1-like decreased gradually in the shoot apex of Zigongdongdou, which is in accordance with the fact that Zigongdongdou maintains vegetative growth in LD. In addition, overexpression of GmSOC1-like stimulated the flowering of Lotus corniculatus cv. supperroot plants. In conclusion, the results of this study indicate that GmSOC1-like may act as a flowering inducer in soybean.
    Plant Cell Reports 05/2013; · 2.94 Impact Factor
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    ABSTRACT: Abundant senescent neutrophils traverse the vascular compartment and may contribute to pathologic conditions. For example, they become procoagulant when undergoing apoptosis and may contribute to thrombosis or inflammation. Our previous studies demonstrated a dominant clearance pathway in which the neutrophils can be phagocytosed by liver macrophages. The aim of this study was to explore an alternate pathway of neutrophil clearance by endothelial cells. Phagocytosis of the neutrophils by endothelial cells was performed using various experimental approaches includingflow cytometry, confocal microscopy and electron microscopy assays in vitro and in vivo. Procoagulant activity of cultured neutrophils was evaluated by coagulation time, factor Xase and prothrombinase assays. Lactadherin functioned as a novel probe for the detection of phosphatidylserine on apoptotic cells, an opsonin (bridge) between apoptotic cell and phagocyte for promoting phagocytosis, and an efficient anticoagulant for inhibition of factor Xase and thrombin formation. When cultured, purified human neutrophils spontaneously entered apoptosis and developed procoagulant activity that was directly related to the degree of phosphatidylserine exposure. Co-culture of aged neutrophils and endothelial cells resulted in phagocytosis of the neutrophils and prolonged coagulation time. Lactadherin diminished the procoagulant activity and increased the rate of neutrophil clearance. In vivo, neutrophils were sequestered by endothelial cells after blockade of Kupffer cells, a process that was dependent upon both phosphatidylserine exposure and P-selectin expression. Thus, the ability of endothelial cells to clear senescent neutrophils may limit the procoagulant and/or inflammatory impact of these cells.
    Thrombosis and Haemostasis 04/2013; 109(6). · 5.76 Impact Factor
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    ABSTRACT: The reduced coenzyme nicotinamide-adenine dinucleotide phosphate (NADPH) is an important molecule in cellular redox balance. Glucose-6-phosphate dehydrogenase (G6PDH) is a key enzyme in the pentose phosphate pathway, the most important NADPH-generating pathway. In this study, roles of G6PDH in maintaining cell redox balance in rice suspension cells under salt stress were investigated. Results showed that the G6PDH activity decreased in the presence of 80 mM NaCl on day 2. Application of exogenous glucose stimulated the activity of G6PDH and NADPH oxidase under salt stress. Exogenous glucose also increased the ion leakage, thiobarbituric acid reactive substances and hydrogen peroxide (H2O2) contents in the presence of 80 mM NaCl on day 2, implying that the reduction of the G6PDH activity was necessary to avoid serious damage caused by salt stress. The NAPDH/NADP+ ratio increased on day 2 but decreased on day 4 under 80 mM NaCl plus glucose treatment. Diphenyleneiodonium, an NADPH oxidase inhibitor, decreased the H2O2 content under 80 mM NaCl treatment on day 2. These results imply that the H2O2 accumulation induced by glucose treatment under salt stress on day 2 was related to the NADPH oxidase. Western-blot analysis showed that the G6PDH expression was slightly induced by glucose and was obviously blocked by DPI on day 2 under salt stress. In conclusion, G6PDH plays a key role in maintaining the cell redox balance in rice suspension cells under salt stress. The coordination of G6PDH and NADPH oxidase is required in maintaining cell redox balance in salt tolerance.
    Plant Growth Regulation 01/2013; 69(2). · 1.63 Impact Factor
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    ABSTRACT: KEY MESSAGE : Two soybean cultivars showed markedly different drought tolerance. G6PDH plays a central role in the process of H ( 2 ) O ( 2 ) regulated GR, DHAR, and MDHAR activities to maintain GSH and Asc levels. Glucose-6-phosphate dehydrogenase (G6PDH) plays a pivotal role in plant resistance to environmental stresses. In this study, we investigated the role of G6PDH in modulating redox homeostasis under drought stress induced by polyethylene glycol 6000 (PEG6000) in two soybean cultivars JINDOU21 (JD-21) and WDD00172 (WDD-172). The G6PDH activity markedly increased and reached a maximum at 96 h in JD-21 and 72 h in WDD-172 during PEG6000 treatments, respectively. Glucosamine (Glucm, a G6PDH inhibitor) obviously inhibited G6PDH activity in both soybeans under PEG6000 treatments. After PEG6000 treatment, JD-21 showed higher tolerance than WDD-172 not only in higher activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR), but also in higher content of glutathione (GSH) and ascorbate (Asc). And we found that hydrogen peroxide (H(2)O(2)) regulated the cell length in root elongation zone. Diphenylene iodonium (DPI, a plasma membrane NADPH oxidase inhibitor) counteracted the PEG6000-induced H(2)O(2) accumulation and decreased the activities of GR, DHAR, and MDHAR as well as GSH and Asc content. Furthermore, exogenous application of H(2)O(2) increased the GR, DHAR, and MDHAR activities that were decreased by Glucm under drought stress. Western blot analysis showed that the G6PDH expression was stimulated by PEG6000 and buthionine sulfoximine (BSO, glutathione biosynthesis inhibitor), and blocked by Glucm, DPI and N-acetyl-L-cysteine (NAC, GSH precursor) in both cultivars. Taken together, our evidence indicates that G6PDH plays a central role in the process of H(2)O(2) regulated GR, DHAR, and MDHAR activities to maintain GSH and Asc levels.
    Plant Cell Reports 12/2012; · 2.94 Impact Factor
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    ABSTRACT: Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in supplying reduced nicotine amide cofactors for biochemical reactions and in modulating the redox state of cells. In this study, the role of G6PDH in thermotolerance of the calli from Przewalskia tangutica and tobacco (Nicotiana tabacum L.) was investigated. Results showed that Przewalskia tangutica callus was more sensitive to heat stress than tobacco callus. The activity of G6PDH and antioxidant enzymes (ascorbate peroxidase, catalase, peroxidase and superoxide dismutase) in calli from Przewalskia tangutica and tobacco increased after 40 °C treatment, although two calli exhibited a difference in the degree and timing of response to heat stress. When G6PDH was partially inhibited by glucosamine pretreatment, the antioxidant enzyme activities and thermotolerance in both calli significantly decreased. Simultaneously, the heat-induced H2O2 content and the plasma membrane NADPH oxidase activity were also reduced. Application of H2O2 increased the activity of G6PDH and antioxidant enzymes in both calli. Diphenylene iodonium, a NADPH oxidase inhibitor, counteracted heatinduced H2O2 accumulation and reduced the heat-induced activity of G6PDH and antioxidant enzymes. Moreover, exogenous H2O2 was effective in restoring the activity of G6PDH and antioxidant enzymes after glucosamine pretreatment. Western blot analysis showed that G6PDH gene expression in both calli was also stimulated by heat and H2O2, and blocked by DPI and glucosamine under heat stress. Taken together, under heat stress G6PDH promoted H2O2 accumulation via NADPH oxidase and the elevated H2O2 was involved in regulating the activity of antioxidant enzymes, which in turn facilitate to maintain the steady-state H2O2 level and protect plants from the oxidative damage.
    Biologia Plantarum 09/2012; 56(3). · 1.74 Impact Factor
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    ABSTRACT: Ethylene and light act through specific signal transduction mechanisms to coordinate the development of higher plants. Application of 1-aminocyclopropane-1-carboxylic acid (ACC, an ethylene precursor) suppresses the hypocotyl elongation of Arabidopsis seedlings in dark, but stimulates it in light. However, the mechanisms of opposite effects of ethylene on hypocotyl elongation in light and dark remain unclear. In the present study, we investigated the key factors involved in the opposite effects of ethylene on hypocotyl elongation in Arabidopsis seedlings. The effects of ACC on hypocotyl elongation of IAA-insensitive mutants including tir1-1, axr1-3, and axr1-12 seedlings were reduced in light but not in dark. The DR5 promoter, a synthetic auxin-response promoter, was used to quantify the level of IAA responses. There was a marked increase in DR5-GFP signals in response to ACC treatment in hypocotyls of DR5-GFP seedlings in light, but not in dark. CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) is an important downstream component of light signaling. ETHYLENE-INSENSITIVE3 (EIN3, an ethylene-stabilized transcription factor) directly regulates ETHYLENE-RESPONSE-FACTOR1 (ERF1). The cop1-4 mutant treated with ACC and cop1-4/EIN3ox plants developed long hypocotyls in darkness. Expression of ERF1 in the cop1-4 mutant was induced by ACC treatment in dark, but the expression of ERF1 in the wild type was not affected. Taken together, ethylene-promoting hypocotyl via IAA is mediated by light, and COP1 has a significant impact on the transcription of some genes downstream of EIN3. Thus, COP1 plays a crucial role in the opposite effects of ethylene on hypocotyl elongation.
    Planta 08/2012; · 3.38 Impact Factor
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    ABSTRACT: The plant hormone auxin plays a central role in the regulation of plant growth and development, as well as in responses to environmental stimuli. Narciclasine (NCS, an Amaryllidaceae alkaloid) isolated from Narcissus tazetta bulbs has a broad range of inhibitory effects on plants. In this study, the role of NCS in responses to auxin in Arabidopsis thaliana roots was investigated. We demonstrated the inhibitory effects of NCS on auxin-inducible lateral root formation, root hair formation, primary root growth, and the expression of primary auxin-inducible genes in Arabidopsis roots using DR5::GUS reporter gene, native auxin promoters (IAA12::GUS, IAA13::GUS), and quantitative reverse transcription PCR analysis. Results also showed that NCS did not affect the expression of cytokinin-inducible ARR5::GUS reporter gene. NCS relieved the auxin-enhanced degradation of the Aux/IAA repressor modulated by the SCFTIR1 ubiquitin-proteasome pathway. In addition, NCS did not alter the auxin-stimulated interaction between IAA7/AXR2 (Aux/IAA proteins) and the F-box protein TIR1 activity of the proteasome. Taken together, these results suggest that NCS acts on the auxin signaling pathway upstream of TIR1, which modulates Aux/IAA protein degradation, and thereby affects the auxin-mediated responses in Arabidopsis roots.
    Planta 04/2012; 236(2):597-612. · 3.38 Impact Factor
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    ABSTRACT: In the present study, we investigated the salt tolerance mechanism of two rice cultivars (Zhenghan-2 and Yujing-6), which show different tolerance to drought and disease. NaCl induced higher extent of lipid peroxide and ion leakage in Yujing-6 roots than those in Zhenghan-2 roots. H2O2 accumulation in Zhenghan-2 roots was lower than that in Yujing-6 roots under salt stress. Comparatively, NaCl treatment did not increase O2− contents in both rice roots, however, O2− level in Yujing-6 roots was higher than that in Zhenghan-2 roots under both control and salt stress conditions. Ascorbate peroxidases (APX) activity increased more significantly in Zhenghan-2 roots than that in Yujing-6 roots. The activity of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and glucose-6-phosphate dehydrogenase (G6PDH) was similarly enhanced in both rice roots under salt stress; however, they showed higher levels in Zhenghan-2 roots than in Yujing-6 roots. Exogenous H2O2 could enhance APX, CAT, POD, SOD and G6PDH activities in a concentration-dependent manner in both rice roots. Diphenylene iodonium (DPI), a plasma membrane (PM) NADPH oxidase inhibitor, which counteracted the NaCl-induced H2O2 accumulation, markedly decreased the activity of above enzymes. Moreover, ion leakage increased dramatically in Zhenghan-2 roots and reached to the similar level of Yujing-6 roots under NaCl+DPI treatment. Taken together, H2O2, which is mainly generated from PM NADPH oxidase, is involved in Zhenghan-2 rice tolerance to salt stress by enhancing the cellular antioxidant level.
    Acta Physiologiae Plantarum 03/2012; 35(3). · 1.52 Impact Factor
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    ABSTRACT: Glucose-6-phosphate dehydrogenase (G6PDH) has been implicated in supplying reduced nicotine amide cofactors for biochemical reactions and in modulating the redox state of cells. In this study, the role of G6PDH in thermotolerance of the calli from Przewalskia tangutica and tobacco (Nicotiana tabacum L.) was investigated. Results showed that Przewalskia tangutica callus was more sensitive to heat stress than tobacco callus. The activity of G6PDH and antioxidant enzymes (ascorbate peroxidase, catalase, peroxidase and superoxide dismutase) in calli from Przewalskia tangutica and tobacco increased after 40 °C treatment, although two calli exhibited a difference in the degree and timing of response to heat stress. When G6PDH was partially inhibited by glucosamine pretreatment, the antioxidant enzyme activities and thermotolerance in both calli significantly decreased. Simultaneously, the heat-induced H2O2 content and the plasma membrane NADPH oxidase activity were also reduced. Application of H2O2 increased the activity of G6PDH and antioxidant enzymes in both calli. Diphenylene iodonium, a NADPH oxidase inhibitor, counteracted heatinduced H2O2 accumulation and reduced the heat-induced activity of G6PDH and antioxidant enzymes. Moreover, exogenous H2O2 was effective in restoring the activity of G6PDH and antioxidant enzymes after glucosamine pretreatment. Western blot analysis showed that G6PDH gene expression in both calli was also stimulated by heat and H2O2, and blocked by DPI and glucosamine under heat stress. Taken together, under heat stress G6PDH promoted H2O2 accumulation via NADPH oxidase and the elevated H2O2 was involved in regulating the activity of antioxidant enzymes, which in turn facilitate to maintain the steady-state H2O2 level and protect plants from the oxidative damage.
    Biologia Plantarum 01/2012; · 1.74 Impact Factor
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    ABSTRACT: The role of hydrogen peroxide in the regulation of glucose-6-phosphate dehydrogenase (G6PDH) activity in the red kidney bean (Phaseolus vulgaris L.) roots under salt stress (100 mM NaCl) was investigated. Salt stress caused the increase of the activities of G6PDH and antioxidative enzymes including ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), as well as H2O2 production. The application of H2O2 (1 mM) also enhanced the activities of G6PDH as well as antioxidative enzymes. In the presence of exogenous CAT, H2O2 content was decreased, and the enhanced activities of G6PDH and antioxidative enzymes induced by NaCl or by exogenous H2O2 were also abolished, suggesting that the enhancement of the above enzyme activities under salt stress was a result of the increased endogenous H2O2 levels. Further results showed that the effects of NaCl and H2O2 on the activities of antioxidative enzymes were diminished by Na3PO4 (a G6PDH inhibitor), suggesting G6PDH activity is required in enhancing the activities of antioxidative enzymes. The enhanced membrane leakage, lipid peroxidation, H2O2 and O2 - contents, G6PDH and antioxidative enzyme activities under salt stress were all recovered to control level when the red kidney bean seedlings treated with 100 mM NaCl for 6 d were transferred to the control conditions for 8 d.
    Biologia Plantarum 01/2012; · 1.74 Impact Factor
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    ABSTRACT: Narciclasine (NCS) is an Amaryllidaceae alkaloid isolated from Narcissus tazetta bulbs. NCS has inhibitory effects on a broad range of biological activities and thus has various potential practical applications. Here we examine how NCS represses plant root growth. Results showed that the inhibition of NCS on cell division in Arabidopsis root tips and its effects on cell differentiation are concentration-dependent; at low concentrations (0.5 and 1.0 μM) NCS preferentially targets mitotic cell cycle specific/cyclin complexes, whereas at high concentration (5.0 μM) the NCS-stimulated accumulation of Kip-related proteins (KRP1 and RP2) affects the CDK complexes with a role at both G1/S and G2/M phases. Our findings suggest that NCS modulates the coordination between cell division and differentiation in Arabidopsis root tips and hence affects the postembryonic development of Arabidopsis seedlings.
    BMC Plant Biology 12/2011; 11:184. · 3.94 Impact Factor
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    ABSTRACT: Narciclasine (NCS) is a plant growth inhibitor isolated from the secreted mucilage of Narcissus tazetta bulbs. It is a commonly used anticancer agent in animal systems. In this study, we provide evidence to show that NCS also acts as an agent in inducing programmed cell death (PCD) in tobacco Bright Yellow-2 (TBY-2) cell cultures. NCS treatment induces typical PCD-associated morphological and biochemical changes, namely cell shrinkage, chromatin condensation and nuclear DNA degradation. To investigate possible signaling events, we analyzed the production of reactive oxygen species (ROS) and the function of mitochondria during PCD induced by NCS. A biphasic behavior burst of hydrogen peroxide (H(2)O(2)) was detected in TBY-2 cells treated with NCS, and mitochondrial transmembrane potential (MTP) loss occurred after a slight increase. Pre-incubation with antioxidant catalase (CAT) and N-acetyl-L-cysteine (NAC) not only significantly decreased the H(2)O(2) production but also effectively retarded the decrease of MTP and reduced the percentage of cells undergoing PCD after NCS treatment. In conclusion, our results suggest that NCS induces PCD in plant cells; the oxidative stress (accumulation of H(2)O(2)) and the MTP loss play important roles during NCS-induced PCD.
    Physiologia Plantarum 09/2011; 144(1):48-58. · 3.26 Impact Factor
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    ABSTRACT: In the present study, the role of phytohormone gibberellins (GAs) on regulating the nitrate reductase (NR) activity was tested in Arabidopsis seedlings. The NR activity in light-grown Col-0 seedlings was reduced by exogenous GA₃ (an active form of GAs), but enhanced by exogenous paclobutrazol (PAC, a gibberellin biosynthesis inhibitor), suggesting that GAs negatively regulate the NR activity in light-grown seedlings. Light is known to influence the NR activity through both photosynthesis and phytochromes. When etiolated seedlings were transferred to white or red light, both exogenously applied GA₃ and PAC were found to function on the NR activity only in the presence of sucrose, implying that GAs are not involved in light signaling-induced but negatively regulate photoproducts-induced NR activity. NR is regulated by light mainly at two levels: transcript level and post-translational level. Our reverse transcription (RT)-PCR assays showed that GAs did not affect the transcript levels of NIA1 and NIA2, two genes that encode NR proteins. But the divalent cations (especially Mg²⁺) were required for GAs negative regulation of NR activity, in view of the importance of divalent cations during the process of post-translational regulation of NR activity, which indicates that GAs very likely regulate the NR activity at the post-translational level. In the following dark-light shift analyses, GAs were found to accelerate dark-induced decrease, but retard light-induced increase of the NR activity. Furthermore, it was observed that application of G₃ or PAC could impair diurnal variation of the NR activity. These results collectively indicate that GAs play a negative role during light regulation of NR activity in nature.
    Journal of plant physiology 08/2011; 168(18):2161-8. · 2.50 Impact Factor
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    ABSTRACT: The roles of ethylene, hydrogen peroxide (H(2)O(2)), and calcium in inducing the capacity of the alternative respiratory pathway (AP) under chilling temperature in Arabidopsis thaliana calli were investigated. Exposure of wild-type (WT) calli, but not the calli of ethylene-insensitive mutants, etr1-3 and ein2-1, to chilling led to a marked increase of the AP capacity and triggered a rapid ethylene emission and H(2)O(2) generation. Increasing ethylene emission by applying 1-aminocyclopropane-1-carboxylic (an ethylene precursor) markedly enhanced the AP capacity in WT calli, but not in etr1-3 and ein2-1 calli, whereas suppressing ethylene emission by applying aminooxyacetic acid (an ethylene biosynthesis inhibitor) abolished the chilling-induced AP capacity in WT calli. Furthermore, exogenous H(2)O(2) treatment increased the AP capacity in WT calli, but not in etr1-3 and ein2-1 calli, while both catalase (H(2)O(2) scavenger) and diphenylene iodonium (DPI, an inhibitor of NADPH oxidase) completely inhibited the chilling-induced H(2)O(2) generation and largely inhibited the chilling-induced AP capacity. Interestingly, the chilling-induced AP capacity was completely inhibited by DPI and EGTA (calcium chelator). Further investigation demonstrated that H(2)O(2) and calcium induced ethylene emission under chilling stress. Ethylene modulated the chilling-induced increase of pyruvate content and the expression of alternative oxidase genes (AOX1a and AOX1c). Taken together, these results indicate that H(2)O(2)-, calcium- and ethylene-dependent pathways are required for chilling-induced increase in AP capacity. However, only ethylene is indispensable for the activation of the AP capacity.
    Planta 08/2011; 235(1):53-67. · 3.38 Impact Factor

Publication Stats

498 Citations
147.96 Total Impact Points

Institutions

  • 2003–2014
    • Lanzhou University
      • School of Life Science
      Kao-lan-hsien, Gansu Sheng, China
  • 2013
    • Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine
      Shanghai, Shanghai Shi, China
  • 2010
    • Northwest Institute of Plateau Biology
      Hsi-ning-shih, Qinghai Sheng, China
  • 2009
    • Beijing University of Technology
      Peping, Beijing, China
    • Chinese Academy of Agricultural Sciences
      • Institute of Crop Sciences
      Beijing, Beijing Shi, China
  • 2006–2009
    • Gansu Agricultural University
      Kao-lan-hsien, Gansu Sheng, China
  • 2001
    • Chinese Academy of Sciences
      Peping, Beijing, China