Root biomass of rice seedlings was increased at lower concentration of exogenous NH 4 + , but it was decreased at higher concentration of exogenous NH 4 + . The level of free NH 4 + in the roots was accumulated gradua...Root biomass of rice seedlings was increased at lower concentration of exogenous NH 4 + , but it was decreased at higher concentration of exogenous NH 4 + . The level of free NH 4 + in the roots was accumulated gradually with the increase of NH 4 + concentration in the nutrient solution. The content of the soluble proteins was essentially constant at higher NH 4 + . The activities of glutamine synthetase (GS), NADH-dependent glutamate synthase (NADH-GOGAT), and NADH-dependent glutamate dehydrogenase (NADH-GDH) were risen with exogenous NH 4 + concentration at the lower NH 4 + concentration range. But the activities of GS and NADH-GOGAT were declined, and the level of NADH-GDH activity was kept constant under higher NH 4 + concentration. The GS/GDH ratio suggested that NH 4 + was assimilated by GS-GOGAT cycle under lower NH 4 + concentration, but NADH-GDH was more important for NH 4 + assimilation and detoxifying NH 4 + to the tissue cells at the higher NH 4 + level. According to the growth and the activity changes of these ammonium-assimilating enzymes of rice seedling roots, 10. 0 μg/mL NH 4 + -N in nutrient solution was more suitable to the rice growth.展开更多
To understand the reallocation of organic nitrogen from leaf to the flower head of rice, the role of glutamine synthetase （GS） was investigated by characterizing GS1 RNAi transgenic rice, which revealed a significa...To understand the reallocation of organic nitrogen from leaf to the flower head of rice, the role of glutamine synthetase （GS） was investigated by characterizing GS1 RNAi transgenic rice, which revealed a significant reduction in panicle number and number of seeds per panicle. We observed the expression of GS isotypes at transcriptional and protein levels in flag leaves, leaf sheaths and panicles at three different flower development stages. The mRNA expression of GS1;1 was clearly suppressed in flag leaves, especially at the flowering stage. GS1 protein was barely detectable in flag leaves until the flowering stage, while GS1 protein was compromised in the leaf sheath and panicle, with transient expression of GS2 protein at the flowering stage. The glutamine level in transgenic plants was significantly reduced in both flag leaves and panicles, but ammonium was highly accumulated. The level of other amino acids, including aspartate and asparagine, tended to be higher in RNAi transgenic plants than the wild type plants during the reproductive stage. In addition, accumulation of toxic ammonium in panicles with low glutamine level might have caused low seed-setting in the transgenic rice. These results indicated that nitrogen reallocation was critical for panicle development, and that multiple GS isotypes functioned cooperatively to complete the rice life cycle when leaf nitrogen was remobilized to the developing reproductive organs.展开更多
To evaluate the protective effects of glutamine in a model of portal hypertension (PH) induced by partial portal vein ligation (PPVL). METHODSMale Wistar rats were housed in a controlled environment and were allowed a...To evaluate the protective effects of glutamine in a model of portal hypertension (PH) induced by partial portal vein ligation (PPVL). METHODSMale Wistar rats were housed in a controlled environment and were allowed access to food and water ad libitum. Twenty-four male Wistar rats were divided into four experimental groups: (1) control group (SO) - rats underwent exploratory laparotomy; (2) control + glutamine group (SO + G) - rats were subjected to laparotomy and were treated intraperitoneally with glutamine; (3) portal hypertension group (PPVL) - rats were subjected to PPVL; and (4) PPVL + glutamine group (PPVL + G) - rats were treated intraperitoneally with glutamine for seven days. Local injuries were determined by evaluating intestinal segments for oxidative stress using lipid peroxidation and the activities of glutathione peroxidase (GPx), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) after PPVL. RESULTSLipid peroxidation of the membrane was increased in the animals subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL procedure showed levels of lipid peroxidation similar to those of the control groups (P > 0.05). The activity of the antioxidant enzyme GTx was decreased in the gut of animals subjected to PH compared with that in the control group of animals not subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL showed similar GTx activity to both the control groups not subjected to PH (P > 0.05). At least 10 random, non-overlapping images of each histological slide with 200 × magnification (44 pixel = 1 μm) were captured. The sum means of all areas, of each group were calculated. The mean areas of eNOS staining for both of the control groups were similar. The PPVL group showed the largest area of staining for eNOS. The PPVL + G group had the second highest amount of staining, but the mean value was much lower than that of the PPVL group (P < 0.01). For iNOS, the control (SO) and control + G (SO + G) groups showed similar areas of staining. The PPVL group contained the largest area of iNOS staining, followed by the PPVL + G group; however, this area was significantly smaller than that of the group that underwent PH without glutamine (P < 0.01). CONCLUSIONTreatment with glutamine prevents gut mucosal injury after PH in rats.展开更多
选用水稻氮高效基因型IR72和9311及氮低效基因型Lemont和PECOS,采用土培方法,在5个施氮量（0、0.51、1.02、1.53、2.04 g N钵-1,分别相当于0、75、150、225、300 kg Nhm-2）处理下,研究了生理生化特性对氮肥的反应及与氮效率的关系。结...选用水稻氮高效基因型IR72和9311及氮低效基因型Lemont和PECOS,采用土培方法,在5个施氮量（0、0.51、1.02、1.53、2.04 g N钵-1,分别相当于0、75、150、225、300 kg Nhm-2）处理下,研究了生理生化特性对氮肥的反应及与氮效率的关系。结果表明,在幼穗分化期,氮高效基因型水稻的可溶性蛋白含量相对低,而谷氨酰胺合成酶（GS）活性高;不同氮效率基因型间1,5-二磷酸核酮糖羧化酶/加氧酶（Rubisco）含量的差异不大;两种氮效率基因型间的净光合速率（Pn）在幼穗分化期差异不明显。而在齐穗期,氮低效基因型的Pn比高效基因型的低28.66%左右;氮低效基因型在两个时期的单位叶绿素光合速率（Pn/Chl）比氮高效基因型分别低18.51%和29.67%左右。在成熟期,氮高效基因型干物质积累能力强,籽粒产量高。这些结果说明氮效率不同的基因型对氮肥的生理反应差异大。相关性分析表明,低氮水平时（0-1.53gN钵-1）,GS酶活性与收获时生物量呈显著或极显著正相关;氮肥偏生产力（PFP）、氮肥农学利用率（AE）及氮素生理利用率（NUEb）分别与GS活性、Pn/Chl和齐穗期的Pn呈显著正相关,而与可溶性蛋白含量、Rubisco含量显著负相关;氮肥吸收效率（RE）与这些生理指标没有显著相关。结果表明水稻光合特征及氮代谢与水稻氮效率间存在紧密的关系,GS活性和可溶性蛋白含量对评价水稻氮肥利用率具有重要的参考价值。展开更多
文摘Root biomass of rice seedlings was increased at lower concentration of exogenous NH 4 + , but it was decreased at higher concentration of exogenous NH 4 + . The level of free NH 4 + in the roots was accumulated gradually with the increase of NH 4 + concentration in the nutrient solution. The content of the soluble proteins was essentially constant at higher NH 4 + . The activities of glutamine synthetase (GS), NADH-dependent glutamate synthase (NADH-GOGAT), and NADH-dependent glutamate dehydrogenase (NADH-GDH) were risen with exogenous NH 4 + concentration at the lower NH 4 + concentration range. But the activities of GS and NADH-GOGAT were declined, and the level of NADH-GDH activity was kept constant under higher NH 4 + concentration. The GS/GDH ratio suggested that NH 4 + was assimilated by GS-GOGAT cycle under lower NH 4 + concentration, but NADH-GDH was more important for NH 4 + assimilation and detoxifying NH 4 + to the tissue cells at the higher NH 4 + level. According to the growth and the activity changes of these ammonium-assimilating enzymes of rice seedling roots, 10. 0 μg/mL NH 4 + -N in nutrient solution was more suitable to the rice growth.
基金supported by by research fund from Chosun University(Grant No.2017-2017)
文摘To understand the reallocation of organic nitrogen from leaf to the flower head of rice, the role of glutamine synthetase （GS） was investigated by characterizing GS1 RNAi transgenic rice, which revealed a significant reduction in panicle number and number of seeds per panicle. We observed the expression of GS isotypes at transcriptional and protein levels in flag leaves, leaf sheaths and panicles at three different flower development stages. The mRNA expression of GS1;1 was clearly suppressed in flag leaves, especially at the flowering stage. GS1 protein was barely detectable in flag leaves until the flowering stage, while GS1 protein was compromised in the leaf sheath and panicle, with transient expression of GS2 protein at the flowering stage. The glutamine level in transgenic plants was significantly reduced in both flag leaves and panicles, but ammonium was highly accumulated. The level of other amino acids, including aspartate and asparagine, tended to be higher in RNAi transgenic plants than the wild type plants during the reproductive stage. In addition, accumulation of toxic ammonium in panicles with low glutamine level might have caused low seed-setting in the transgenic rice. These results indicated that nitrogen reallocation was critical for panicle development, and that multiple GS isotypes functioned cooperatively to complete the rice life cycle when leaf nitrogen was remobilized to the developing reproductive organs.
文摘To evaluate the protective effects of glutamine in a model of portal hypertension (PH) induced by partial portal vein ligation (PPVL). METHODSMale Wistar rats were housed in a controlled environment and were allowed access to food and water ad libitum. Twenty-four male Wistar rats were divided into four experimental groups: (1) control group (SO) - rats underwent exploratory laparotomy; (2) control + glutamine group (SO + G) - rats were subjected to laparotomy and were treated intraperitoneally with glutamine; (3) portal hypertension group (PPVL) - rats were subjected to PPVL; and (4) PPVL + glutamine group (PPVL + G) - rats were treated intraperitoneally with glutamine for seven days. Local injuries were determined by evaluating intestinal segments for oxidative stress using lipid peroxidation and the activities of glutathione peroxidase (GPx), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) after PPVL. RESULTSLipid peroxidation of the membrane was increased in the animals subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL procedure showed levels of lipid peroxidation similar to those of the control groups (P > 0.05). The activity of the antioxidant enzyme GTx was decreased in the gut of animals subjected to PH compared with that in the control group of animals not subjected to PH (P < 0.01). However, the group that received glutamine for seven days after the PPVL showed similar GTx activity to both the control groups not subjected to PH (P > 0.05). At least 10 random, non-overlapping images of each histological slide with 200 × magnification (44 pixel = 1 μm) were captured. The sum means of all areas, of each group were calculated. The mean areas of eNOS staining for both of the control groups were similar. The PPVL group showed the largest area of staining for eNOS. The PPVL + G group had the second highest amount of staining, but the mean value was much lower than that of the PPVL group (P < 0.01). For iNOS, the control (SO) and control + G (SO + G) groups showed similar areas of staining. The PPVL group contained the largest area of iNOS staining, followed by the PPVL + G group; however, this area was significantly smaller than that of the group that underwent PH without glutamine (P < 0.01). CONCLUSIONTreatment with glutamine prevents gut mucosal injury after PH in rats.
文摘选用水稻氮高效基因型IR72和9311及氮低效基因型Lemont和PECOS,采用土培方法,在5个施氮量（0、0.51、1.02、1.53、2.04 g N钵-1,分别相当于0、75、150、225、300 kg Nhm-2）处理下,研究了生理生化特性对氮肥的反应及与氮效率的关系。结果表明,在幼穗分化期,氮高效基因型水稻的可溶性蛋白含量相对低,而谷氨酰胺合成酶（GS）活性高;不同氮效率基因型间1,5-二磷酸核酮糖羧化酶/加氧酶（Rubisco）含量的差异不大;两种氮效率基因型间的净光合速率（Pn）在幼穗分化期差异不明显。而在齐穗期,氮低效基因型的Pn比高效基因型的低28.66%左右;氮低效基因型在两个时期的单位叶绿素光合速率（Pn/Chl）比氮高效基因型分别低18.51%和29.67%左右。在成熟期,氮高效基因型干物质积累能力强,籽粒产量高。这些结果说明氮效率不同的基因型对氮肥的生理反应差异大。相关性分析表明,低氮水平时（0-1.53gN钵-1）,GS酶活性与收获时生物量呈显著或极显著正相关;氮肥偏生产力（PFP）、氮肥农学利用率（AE）及氮素生理利用率（NUEb）分别与GS活性、Pn/Chl和齐穗期的Pn呈显著正相关,而与可溶性蛋白含量、Rubisco含量显著负相关;氮肥吸收效率（RE）与这些生理指标没有显著相关。结果表明水稻光合特征及氮代谢与水稻氮效率间存在紧密的关系,GS活性和可溶性蛋白含量对评价水稻氮肥利用率具有重要的参考价值。
