Nitrous oxide emissions and nitrogen cycling in managed grassland in Southern Hokkaido,Japan     

《Soil Science and Plant Nutrition》2013,59(4):676-688

Abstract

Nitrous oxide (N₂O) emissions were measured and nitrogen (N) budgets were estimated for 2?years in the fertilizer, manure, control and bare plots established in a reed canary grass (Phalaris arundinacea L.) grassland in Southern Hokkaido, Japan. In the manure plot, beef cattle manure with bark was applied at a rate of 43–44?Mg fresh matter (236–310?kg?N)?ha^?1?year^?1, and a supplement of chemical fertilizer was also added to equalize the application rate of mineral N to that in the fertilizer plots (164–184?kg?N?ha^?1?year^?1). Grass was harvested twice per year. The total mineral N supply was estimated as the sum of the N deposition, chemical fertilizer application and gross mineralization of manure (GMm), soil (GMs), and root-litter (GMl). GMm, GMs and GMl were estimated by dividing the carbon dioxide production derived from the decomposition of soil organic matter, root-litter and manure by each C?:?N ratio (11.1 for soil, 15.5 for root-litter and 23.5 for manure). The N uptake in aboveground biomass for each growing season was equivalent to or greater than the external mineral N supply, which is composed of N deposition, chemical fertilizer application and GMm. However, there was a positive correlation between the N uptake in aboveground biomass and the total mineral N supply. It was assumed that 58% of the total mineral N supply was taken up by the grass. The N supply rates from soil and root-litter were estimated to be 331–384?kg?N?ha^?1?year^?1 and 94–165?kg?N?ha^?1?year^?1, respectively. These results indicated that the GMs and GMl also were significant inputs in the grassland N budget. The cumulative N₂O flux for each season showed a significant positive correlation with mineral N surplus, which was calculated as the difference between the total mineral N supply and N uptake in aboveground biomass. The emission factor of N₂O to mineral N surplus was estimated to be 1.2%. Furthermore, multiple regression analysis suggested that the N₂O emission factor increased with an increase in precipitation. Consequently, soil and root-litter as well as chemical fertilizer and manure were found to be major sources of mineral N supply in the grassland, and an optimum balance between mineral N supply and N uptake is required for reducing N₂O emission.  相似文献   

Effects of Scutellaria barbata flavonoids on abnormal expression of NOS,HSP70 and apoE induced by Aβ 25-35 in rat astrocytes     

FAN Yue  WU Xiao-guang  ZHAO Hong-xiang  SHANG Ya-zhen 《园艺学报》2014,30(2):359-379

AIM:To study the effects of Scutellaria barbata flavonoids (SBF) on abnormal expression of nitric oxide synthase (NOS), heat-shock protein 70 (HSP70) and apolipoprotein E (apoE) induced by Aβ 25-35 in rat astrocytes. METHODS:The third generation of cultured rat astrocytes was divided into 5 groups. The cells in 3 drug treatment groups were given SBF at dose of 17.5 mg/L, 35 mg/L and 70 mg/L for 24 h, and then the cells in model group and 3 doses of SBF groups were exposed to Aβ 25-35 at concentration of 100 μmol/L for 24 h. The expression of endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS) in the cultured cells was assayed by immunohistochemical method. The expression of HSP70 was estimated by Western blotting and the mRNA expression of apoE was assessed by RT-PCR. RESULTS:Compared with control group, the protein level of eNOS were significantly decreased and the protein level of iNOS increased (P<0.01) in model group. The protein expression of HSP70 and mRNA expression of apoE were notably increased (P<0.01) in model group. However, these disturbances were attenuated by SBF at dose of 17.5, 35 and 70 mg/L (P<0.01). CONCLUSION:SBF has an obvious protective effect on damaged astrocytes induced by Aβ 25-35, suggesting that SBF may be helpful for the treatment of Alzheimer disease.  相似文献   

Chloride currents activated by cisplatin in poorly differentiated naso-pharyngeal carcinoma cells are not Ca2+-activated chloride currents     

YANG Xiao-ya  LIU Mei  WU Jia-bao  LAI Zhou-yi  WANG Yuan  FAN Ai-hui  ZHU Lin-yan  MAO Jian-wen  WANG Li-wei  CHEN Li-xin 《园艺学报》2014,30(6):968-974

AIM：To investigate the type of chloride channel activated by cisplatin in poorly differentiated nasopharyngeal carcinoma cells (CNE-2Z cells). METHODS：The technique of whole-cell patch-clamp was used to investigate the role of Ca2+ in the activation of cisplatin-activated chloride currents and to analyze the effect of hypertonic stress on these currents in CNE-2Z cells. RESULTS：Chloride currents were induced when the cells were exposed to the calcium-free cisplatin solution, showing the similar density to the currents induced by cisplatin with the presence of extracellular calcium. However, the latency and the peak time of cisplatin-activated currents in the absence of extracellular calcium were prolonged. The activation of cisplatin-activated chloride currents was insensitive to the depletion of intra- and extracellular calcium. Calcium channel antagonist nifedipine had no effect on the cisplatin-activated chloride currents, while hypertonic solution completely inhibited those currents. CONCLUSION：The cisplatin-activated chloride currents are independent on intra/extracellular calcium. The chloride channels activated by cisplatin are not calcium-activated chloride channels, but are probably volume-sensitive chloride channels.  相似文献   

Role of miRNA-24 in regulation of endothelial nitric oxide synthase expression and vascular endothelial cell proliferation     

ZHANG Wen-yu  WANG Hui  LI Yu-mei  CHEN Wei  HU Nan  OU He-sheng 《园艺学报》2014,30(8):1415-1420

AIM：To investigate whether miRNA-24 is involved in the regulation of endothelial nitric oxide synthase (eNOS) expression and vascular endothelial cell proliferation. METHODS：A plasmid that highly expressed miRNA-24 was constructed, and was transfected into the human umbilical vein endothelial cells (HUVECs) by liposome. The cell proliferation was detected by MTT assay. The expression of eNOS and Sp1 at mRNA and protein levels was exa-mined by real-time PCR, immunohistochemistry and Western blotting.RESULTS：Compared with control group, the proliferation of endothelial cells in miRNA-24 group was significantly decreased by 41.97 % (0.47±0.04 vs 0.81±0.03, P<0.01), and the expression of eNOS at mRNA and protein levels was decreased by 44.8% (0.48±0.01 vs 0.87±0.03, P<0.05) and 71.92% (0.16±0.06 vs 0.57±0.08, P<0.05), respectively. Meanwhile, the mRNA and protein levels of Sp1 were significantly decreased by 53.00% (0.45±0.02 vs 0.93±0.01, P<0.05) and by 62.31% (0.13±0.07 vs 0.31±0.09, P<0.05), respectively. In miRNA-24 inhibitor group, the above indexes were decreased compared with control group, but significantly increased compared with miRNA-24 group. CONCLUSION：miRNA-24 significantly inhibits the proliferation of HUVECs and the eNOS expression. Sp1 possibly acts as one of the important factors in the regulation of eNOS expression by miRNA-24.  相似文献   

对虾血细胞中一氧化氮合成酶鉴定与分析方法研究   总被引：7，自引：0，他引：7       下载免费PDF全文

姜国建  于仁诚  王云峰  颜天  周名江 《中国水产科学》2004,11(3):177-184

通过硝基蓝四唑(NBT)还原法和血细胞形态法两种一氧化氮合成酶的鉴定方法,以日本对虾(Penaeus japonicus)作为研究对象,对日本对虾血细胞中的一氧化氮合成酶进行初步鉴定,并优化硝基蓝四唑(NBT)还原法测定对虾血细胞中一氧化氮合成酶的实验条件.结果显示,当L-精氨酸浓度为2.5 mmol/L,脂多糖(LPS)质量浓度为100 μg/mL,Ca2 浓度为2.5 mmol/L时,NBT法测定一氧化氮合成酶活力的结果最佳.同时,还建立了两种针对一氧化氮合成酶活力的分析方法-L-瓜氨酸分析法和亚硝酸盐分析法,并对其测定条件进行了优化.结果表明,对虾血细胞在4 ℃下与L-精氨酸和LPS孵育8 h后测定的结果最为理想.利用这4种方法能够有效地鉴定和分析对虾血细胞中的一氧化氮合成酶,这为深入了解一氧化氮合成酶在对虾先天性免疫中的地位及其在对虾抗病力中的作用提供了理论依据.  相似文献   

Pulsed delivery of nitric oxide counteracts hypoxaemia in the anaesthetized horse     

Erkki Heinonen Lic Tech  Göran Hedenstierna MD  PhD  Pekka Meriläinen PhD  Marieann Högman PhD  Görel Nyman DVM  PhD 《Veterinary anaesthesia and analgesia》2001,28(1):3-11

Objective To study the effect of the pulsed delivery of nitric oxide (NO) on pulmonary gas exchange in the anaesthetized horses. Design Prospective, controlled randomized. Animals Five healthy Standardbred trotters, three geldings and two mares. Methods The horses were anaesthetized with thiopentone and isoflurane and positioned in dorsal recumbency. Nitric oxide was added as a pulse to the inspired gas during the first half of each inspiration. In three horses the effect of NO on the ventilation–perfusion distribution was also investigated using the multiple inert gas elimination technique. Data were analysed with repeated measures ANOVA. Results During spontaneous breathing, arterial oxygen tension (PaO₂) increased with NO inhalation, from 14 ± 2 to 29 ± 3 kPa (105 ± 15 to 218 ± 23 mm Hg) (p < 0.001). Arterial oxygen tension also increased, from 17 ± 3 to 31 ± 5 kPa (128 ± 23 to 233 ± 38 mm Hg) (p < 0.05) during intermittent positive pressure ventilation. The increase in PaO₂ was mainly due to a reduced right to left vascular shunt, but ventilation and perfusion matching also improved. The beneficial effect of NO inhalation was lost within 5 minutes of its discontinuation. Conclusion Delivery of NO as a pulse during inspiration is an effective method for counteracting impaired gas exchange caused by anaesthesia in horses. Pulsation has to be continuous because of the transience of NO's therapeutic effect. Clinical relevance Horses with impaired pulmonary gas exchange during anaesthesia can be treated with pulsed NO inhalation.  相似文献   

Effects of preharvest nitric oxide treatment on ethylene biosynthesis and soluble sugars metabolism in ‘Golden Delicious’ apples     

《Postharvest Biology and Technology》2013

In order to examine the influence of preharvest nitric oxide (NO) treatment on ethylene biosynthesis and soluble sugar metabolism in ‘Golden Delicious’ apples, apple trees were sprayed with 50 μM sodium nitroprusside (SNP) (a donor of NO) 14 days before harvest. The results indicated that preharvest SNP treatment can increase the NO content and the NOS activity in apple fruit, therefore, delay the accumulation of ethylene due to its inhibition on the activities of 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxydase (ACO). Fructose is the main sugar in ‘Golden Delicious’ apple. The synthesis of sucrose was stimulated and the decomposition of sucrose was inhibited by this treatment, thus causing the accumulation of sucrose. We can draw a conclusion that pre-harvest SNP (50 μM) treatment can increase the NO content of fruit during storage, while higher NO content can further regulate fruit ripening through its effect on ethylene and sugar metabolism in ‘Golden Delicious’ apple fruit during storage at 18 °C.  相似文献   

The effects of nitric oxide and nitrous oxide on enzymatic browning in longkong (Aglaia dookkoo Griff.)     

《Postharvest Biology and Technology》2013

The effect of nitric oxide and nitrous oxide on pericarp browning of longkong fruit was studied. The fruit was either dipped for 5 min in 0.25 mM sodium nitroprusside (SNP), a nitric oxide donor, or continually exposed to 90% nitrous oxide (N₂O) vapour for 3 h and was compared to the untreated fruit (control). The fruits were then stored at 13 °C and RH of 90 ± 5%. The fruit treated for 3 h with nitrous oxide vapour had delayed pericarp browning with higher phenolic compounds. However, these fruit showed lower levels of phenylalanine ammonia lyase, polyphenol oxidase and peroxidase than the control fruit and those treated with 0.25 mM SNP. Therefore, we conclude that nitrous oxide delays browning and reduces the activities of browning enzymes in longkong pericarp.  相似文献   

Induction of Toll-like receptor 4 signaling in avian macrophages inhibits infectious laryngotracheitis virus replication in a nitric oxide dependent way     

Siamak Haddadi  Dae-Sun KimHui Jasmine  Frank van der MeerMarkus Czub  Mohamed Faizal Abdul-Careem 《Veterinary immunology and immunopathology》2013

LPS is one of the pathogen associated molecular patterns that activates Toll-like receptor 4 (TLR4) signaling pathway eliciting antiviral host responses in mammals although information on such responses in avian species is scarce. Our objectives were to characterize the LPS induced innate responses particularly the expression of LPS receptors (TLR4, CD14) in avian macrophages and observe whether TLR4 mediated induction of NO can elicit antiviral response against infectious laryngotracheitis virus (ILTV) replication. We found that LPS was capable of inducing the expression of TLR4, CD14 and NO production but not the type 1 interferons in an avian macrophage cell line, MQ-NCSU. We also showed that TLR4 mediated NO production can lead to antiviral response against ILTV replication when MQ-NCSU cells were treated with LPS and the resultant supernatant was then transferred to ILTV replicating cells to assess antiviral activity. Antiviral activity of NO was blocked by a selective inhibitor, S-methylisothiourea sulfhate that inhibits inducible NO synthase. This observation confirms that the antiviral activity is positively correlated with NO production. The data show that LPS can be a potential innate immune stimulant that can be used against ILTV infection in chickens that require further evaluation in vivo.  相似文献   

Ca²⁺诱导损伤线粒体超微结构的原子力显微镜研究     

王霖  朱杰  王国栋 《西北农业学报》2013,22(6):148-152

采用Ca²⁺急性诱导构建线粒体损伤模型,分别通过透射电子显微镜和原子力显微镜观测线粒体内部结构和表面形貌的变化,用以探究线粒体损伤过程中结构变化的规律性。结果显示,线粒体在Ca²⁺诱导下的损伤过程依照内部结构的变化规律可分为前后2个阶段：前期以嵴有序结构的破坏为特征,线粒体内部特异性结构逐步被破坏,无明显肿胀趋势;后期以线粒体嵴间隙膨胀、嵴囊泡化为特征,线粒体迅速膨胀并向球形变化,线粒体的最终裂解应存在临界条件,决定于线粒体外膜的张力特性。  相似文献