Nitrate reductase activity (NRA) in different plant organs and leaves in different positions of Camptotheca acuminata seedlings was determined by an In vivo assay, the diurnal variation rhythm of NRA in leaves of diff...Nitrate reductase activity (NRA) in different plant organs and leaves in different positions of Camptotheca acuminata seedlings was determined by an In vivo assay, the diurnal variation rhythm of NRA in leaves of different positions was observed,and the correlations between leaf NRA, leaf area and lamina mass per unit area (LMA) were also examined. The results showed that NRA in the leaf was significantly highest, compared with that in other organs such as roots, stems and leaves. In this experiment, the 10 leaves were selected from the apex to the base of the seedlings in order. The different NRA occurred obviously in leaves of different positions of C. acuminata seedlings from the apex to the base, and NRA was higher in the 4th-6th leaves.The diurnal change rhythm of leaf NRA showed a one peak curve, and maximum NRA value appeared at about midday (at 12:30 or so). No obvious correlations between NRA and leaf area or lamina mass per unit area were observed. This study offered scientific foundation for the further research on nitrogen metabolism of C. acuminata.展开更多
[Objective] The research aimed to study the circadian rhythm of nitrate re- ductase activity (NRA) in plant. [Method] The wheat plants at heading stage were used as the materials for the measurement of dynamic chang...[Objective] The research aimed to study the circadian rhythm of nitrate re- ductase activity (NRA) in plant. [Method] The wheat plants at heading stage were used as the materials for the measurement of dynamic changes of nitrate reductase activity (NRA) within 24 h under the conditions of constant high temperature. [Resulti The fluctuation of NRA in wheat changed greatly from 20:00 pm to 11:00 am. The enzyme activity remained constant, but at 14:00 the enzyme activity was the high- est, higher than all the other time points except the enzyme activity measured at11:00. The enzyme activity was the lowest of 17:00, which was lower than all the other time points except the enzyme activity measured at 2:00. [Conclusion] There were autonomous rhythm changes of NRA in wheat in a certain degree.展开更多
Based on the strong chelating property of bathophenanthroline disulfonic acid (BPDS) with root chelate reductase activity is usually measured with a spectrophotometer using MES (2-morpholinoethanesulfonic acid) or HEP...Based on the strong chelating property of bathophenanthroline disulfonic acid (BPDS) with root chelate reductase activity is usually measured with a spectrophotometer using MES (2-morpholinoethanesulfonic acid) or HEPES (2-(4-(2-Hydroxyethyl)-1-piperazinyl) ethanesulfonic acid) buffer in the dark because of high autoreduction rate of in the presence of light. However, the exclusion of light is inconvenient, especially when analyzing a large number of samples. The objective of this study was to develop a new method for determination of root reductase activity under normal laboratory conditions using a suitable buffer composition and concentration to eliminate the autoreduction of A modified method using a Tris (2-amino-2-hydroxymethyl-1,3-propanediol) buffer at pH 7.5 instead of MES or HEPES buffer and a decreased FeEDTA (Fe ethylene diamine tetraacetic acid) concentration of 50 μmol L-1 was developed. The autoreduction of using the Tris buffer was undetectable for temperatures at 4 and 28 °C and was also much lower than that using the other buffers even with sunlight during measurement of reduction. Furthermore, the differences in reductase activity among 5 plant species and 14 red clover cultivars (Trifolium pratense L.) could be easily detected with the modified method. The method developed in this study to measure root Fe chelate reductase activity was not only effective and reliable but also easily managed under normal laboratory light conditions.展开更多
Gracilariopsis lemaneiformis is an economically-valued species and widely cultured in China at present.After being acclimated to diff erent growth temperatures(15,20,25,and 30°C)for 7 days,the relative growth rat...Gracilariopsis lemaneiformis is an economically-valued species and widely cultured in China at present.After being acclimated to diff erent growth temperatures(15,20,25,and 30°C)for 7 days,the relative growth rate(RGR),nitrate reductase activity,soluble protein content and chlorophyll a fl uorescence of G.lemaneiformis were examined.Results show that RGR was markedly aff ected by temperature especially at 20°C at which G.lemaneiformis exhibited the highest eff ective quantum yield of PSII[Y(II)]and lightsaturated electron transport rate(ETR max),but the lowest non-photochemical quenching.Irrespective of growth temperature,the nitrate reductase activity increased with the incubation temperature from 15 to 30°C.In addition,the greatest nitrate reductase activity was found in the thalli grown at 20°C.The value of temperature coeffi cient Q10 of alga cultured in 15°C was the greatest among those of other temperatures tested.Results indicate that the optimum temperature for nitrate reductase synthesis was relatively lower than that for nitrate reductase activity,and the relationship among growth,photosynthesis,and nitrate reductase activity showed that the optimum temperature for activity of nitrate reductase in vivo assay should be the same to the optimal growth temperature.展开更多
Study on the effects of allelochemicals such as trans \|ferulic acid ( t \|FA), benzoic acid (BA) and p \|hydroxybenzoic acid ( p \|HA), isolated from decomposed wheat straw on the activity of nitrate reduct...Study on the effects of allelochemicals such as trans \|ferulic acid ( t \|FA), benzoic acid (BA) and p \|hydroxybenzoic acid ( p \|HA), isolated from decomposed wheat straw on the activity of nitrate reductase at different concentrations of allelochemicals and different pH is described. t \|FA (0.26, 2.58 and 5.15 mmol/L) and BA (4.09, 8.19 mmol/L) showed a certain inhibition to the activity of nitrate reductase. The highest inhibition rate was 18.40%, but BA (0.41 mmol/L) and p \|HA (0.36, 1.81 and 3.62 mmol/L) showed stimulation, the more strong stimulation rate was 15.80%. At pH 6 condition, the activity of nitrate reductase was stronger inhibited than pH 7 and pH 8, but the mixture of 3 allelochemicals at pH 6 showed a stimulation. The mixture, however, at pH 7 and pH 8 showed some inhibition. It was found that there was a relationship between production of NO\+-\-2 and transformation of NO\+-\-3.展开更多
Summary: Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed...Summary: Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed at early developmental stages. The main objective of the present study was to investigate the effects of NR2B gene knockdown on the functional integration of the adult-born granule cells gen- erated from the subgranule zone (SGZ) in the hippocampus. The small interfering RNA (siRNA) was used to knock down the NR2B gene in the adult-born hippocampal neurons. In the functional integration test, the mice were exposed to a novel environment (open field arena), and the expression of c-fos was immunohistochemically detected in the hippocampus. After exposure to the novel environment, siRNA-NR2B mice were significantly different from control mice in either the number of squares or the number of rears they crossed, showing decreased horizontal and vertical activity (P〈0.05). Moreover, the c-fos expression was increased in both control and siRNA-NR2B mice after open field test. But, it was significantly lower in siRNA-NR2B neurons than in control neurons. It was concluded that the neu- ral activity of newborn neurons is regulated by their own NR2B-containing NMDA glutamate receptors during a short, critical period after neuronal birth.展开更多
Reticulocytosls in rats was induced by repetitive bleeding. Both the in vitro and the in vivo studies showed that the detected reductive speed of methemoglobin of the bleeding group was faster than that of the control...Reticulocytosls in rats was induced by repetitive bleeding. Both the in vitro and the in vivo studies showed that the detected reductive speed of methemoglobin of the bleeding group was faster than that of the control group at all time intervals. At the same time, the NADH-cytochrome b5 methemoglobin reductase activity and the molybdenum content in erythrocytes of the bleeding group were significantly increased. Regressional analysis showed that there was a significantly positive correlation between the enzyme activity and the molybdenum content. It is proposed that molybdenum might be required for the enzyme activity展开更多
Since we had previously demonstrated that siRNAs to tristetraprolin (TTP) markedly inhibited insulin stimulation of hepatic HMG-CoA reductase (HMGR) transcription, we investigated the effects of transfecting rat liver...Since we had previously demonstrated that siRNAs to tristetraprolin (TTP) markedly inhibited insulin stimulation of hepatic HMG-CoA reductase (HMGR) transcription, we investigated the effects of transfecting rat liver with TTP constructs. We found that transfecting diabetic rats with TTP did not increase HMGR transcription but rather led to modest inhibition. We then investigated whether co-transfection with protein kinase B, hepatic form (AKT2), might lead to phosphorylation and result in activation of HMGR transcription. We found that this treatment resulted in near complete inhibition of transcription. Transfection with peroxisome proliferator-activated receptor g coactivator (PGC-1a) also inhibited HMGR transcription. These results show that although TTP is needed for activation of HMGR transcription, it cannot by itself activate this process. AKT2 and PGC-1a, which mediate the activation of gluconeogenic genes by insulin, exert the opposite effect on HMGR.展开更多
A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage(Bra...A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage(Brassica parachinensis Bailey).The results showed that all the application of these four amino acids could increase the yield of flowering Chinese cabbage,significantly raise the content of soluble sugar,and reduce the accumulation of nitrate.The applications of three other amino acids except alanine can increase the content of soluble proteins and decrease the accumulation of oxalic acid.However,the application of amino acid has insignificant influences on the SPAD number of chlorophyll,and causes the decrease of Vitamin C content.Meanwhile,the application of amino acid can improve the activity of nitrate reductase(NR) and glutamate dehydrogenase(GDH) as well.It shows that the application of amino acid is beneficial to improve ammonia metabolism,reduce the accumulation of nitrate and oxalic acid,increase the content of soluble sugar and soluble proteins,and improve the quality of flowering Chinese cabbage.展开更多
文摘Nitrate reductase activity (NRA) in different plant organs and leaves in different positions of Camptotheca acuminata seedlings was determined by an In vivo assay, the diurnal variation rhythm of NRA in leaves of different positions was observed,and the correlations between leaf NRA, leaf area and lamina mass per unit area (LMA) were also examined. The results showed that NRA in the leaf was significantly highest, compared with that in other organs such as roots, stems and leaves. In this experiment, the 10 leaves were selected from the apex to the base of the seedlings in order. The different NRA occurred obviously in leaves of different positions of C. acuminata seedlings from the apex to the base, and NRA was higher in the 4th-6th leaves.The diurnal change rhythm of leaf NRA showed a one peak curve, and maximum NRA value appeared at about midday (at 12:30 or so). No obvious correlations between NRA and leaf area or lamina mass per unit area were observed. This study offered scientific foundation for the further research on nitrogen metabolism of C. acuminata.
基金Supported by the National Natural Science Foundation of China(31160254)~~
文摘[Objective] The research aimed to study the circadian rhythm of nitrate re- ductase activity (NRA) in plant. [Method] The wheat plants at heading stage were used as the materials for the measurement of dynamic changes of nitrate reductase activity (NRA) within 24 h under the conditions of constant high temperature. [Resulti The fluctuation of NRA in wheat changed greatly from 20:00 pm to 11:00 am. The enzyme activity remained constant, but at 14:00 the enzyme activity was the high- est, higher than all the other time points except the enzyme activity measured at11:00. The enzyme activity was the lowest of 17:00, which was lower than all the other time points except the enzyme activity measured at 2:00. [Conclusion] There were autonomous rhythm changes of NRA in wheat in a certain degree.
基金1 Project supported by the National Natural Science Foundation of China (No. 40271065) and the Science and TechnologyAgency of Japan for Postdoctoral Fellows.
文摘Based on the strong chelating property of bathophenanthroline disulfonic acid (BPDS) with root chelate reductase activity is usually measured with a spectrophotometer using MES (2-morpholinoethanesulfonic acid) or HEPES (2-(4-(2-Hydroxyethyl)-1-piperazinyl) ethanesulfonic acid) buffer in the dark because of high autoreduction rate of in the presence of light. However, the exclusion of light is inconvenient, especially when analyzing a large number of samples. The objective of this study was to develop a new method for determination of root reductase activity under normal laboratory conditions using a suitable buffer composition and concentration to eliminate the autoreduction of A modified method using a Tris (2-amino-2-hydroxymethyl-1,3-propanediol) buffer at pH 7.5 instead of MES or HEPES buffer and a decreased FeEDTA (Fe ethylene diamine tetraacetic acid) concentration of 50 μmol L-1 was developed. The autoreduction of using the Tris buffer was undetectable for temperatures at 4 and 28 °C and was also much lower than that using the other buffers even with sunlight during measurement of reduction. Furthermore, the differences in reductase activity among 5 plant species and 14 red clover cultivars (Trifolium pratense L.) could be easily detected with the modified method. The method developed in this study to measure root Fe chelate reductase activity was not only effective and reliable but also easily managed under normal laboratory light conditions.
基金Supported by the National Key R&D Program of China(No.2017YFC0506200)the Shandong Province Science Foundation for Youths(No.ZR201807120023)+3 种基金the Key Research and Development Program of Yantai(No.2018ZHGY082)the China Agriculture Research System(No.CARS-50)the Financial Fund of the Ministry of Agriculture and Rural Aff airs,China(No.NFZX2018)the Project of Guangdong Province Education Department(No.2017KCXTD014)。
文摘Gracilariopsis lemaneiformis is an economically-valued species and widely cultured in China at present.After being acclimated to diff erent growth temperatures(15,20,25,and 30°C)for 7 days,the relative growth rate(RGR),nitrate reductase activity,soluble protein content and chlorophyll a fl uorescence of G.lemaneiformis were examined.Results show that RGR was markedly aff ected by temperature especially at 20°C at which G.lemaneiformis exhibited the highest eff ective quantum yield of PSII[Y(II)]and lightsaturated electron transport rate(ETR max),but the lowest non-photochemical quenching.Irrespective of growth temperature,the nitrate reductase activity increased with the incubation temperature from 15 to 30°C.In addition,the greatest nitrate reductase activity was found in the thalli grown at 20°C.The value of temperature coeffi cient Q10 of alga cultured in 15°C was the greatest among those of other temperatures tested.Results indicate that the optimum temperature for nitrate reductase synthesis was relatively lower than that for nitrate reductase activity,and the relationship among growth,photosynthesis,and nitrate reductase activity showed that the optimum temperature for activity of nitrate reductase in vivo assay should be the same to the optimal growth temperature.
基金Foundationitem :NationalNaturalScienceFoundationofChina (No .3 9790 1 0 0 )
文摘Study on the effects of allelochemicals such as trans \|ferulic acid ( t \|FA), benzoic acid (BA) and p \|hydroxybenzoic acid ( p \|HA), isolated from decomposed wheat straw on the activity of nitrate reductase at different concentrations of allelochemicals and different pH is described. t \|FA (0.26, 2.58 and 5.15 mmol/L) and BA (4.09, 8.19 mmol/L) showed a certain inhibition to the activity of nitrate reductase. The highest inhibition rate was 18.40%, but BA (0.41 mmol/L) and p \|HA (0.36, 1.81 and 3.62 mmol/L) showed stimulation, the more strong stimulation rate was 15.80%. At pH 6 condition, the activity of nitrate reductase was stronger inhibited than pH 7 and pH 8, but the mixture of 3 allelochemicals at pH 6 showed a stimulation. The mixture, however, at pH 7 and pH 8 showed some inhibition. It was found that there was a relationship between production of NO\+-\-2 and transformation of NO\+-\-3.
基金supported by the National Natural Science Foundation of China(No.81000537)
文摘Summary: Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed at early developmental stages. The main objective of the present study was to investigate the effects of NR2B gene knockdown on the functional integration of the adult-born granule cells gen- erated from the subgranule zone (SGZ) in the hippocampus. The small interfering RNA (siRNA) was used to knock down the NR2B gene in the adult-born hippocampal neurons. In the functional integration test, the mice were exposed to a novel environment (open field arena), and the expression of c-fos was immunohistochemically detected in the hippocampus. After exposure to the novel environment, siRNA-NR2B mice were significantly different from control mice in either the number of squares or the number of rears they crossed, showing decreased horizontal and vertical activity (P〈0.05). Moreover, the c-fos expression was increased in both control and siRNA-NR2B mice after open field test. But, it was significantly lower in siRNA-NR2B neurons than in control neurons. It was concluded that the neu- ral activity of newborn neurons is regulated by their own NR2B-containing NMDA glutamate receptors during a short, critical period after neuronal birth.
文摘Reticulocytosls in rats was induced by repetitive bleeding. Both the in vitro and the in vivo studies showed that the detected reductive speed of methemoglobin of the bleeding group was faster than that of the control group at all time intervals. At the same time, the NADH-cytochrome b5 methemoglobin reductase activity and the molybdenum content in erythrocytes of the bleeding group were significantly increased. Regressional analysis showed that there was a significantly positive correlation between the enzyme activity and the molybdenum content. It is proposed that molybdenum might be required for the enzyme activity
文摘Since we had previously demonstrated that siRNAs to tristetraprolin (TTP) markedly inhibited insulin stimulation of hepatic HMG-CoA reductase (HMGR) transcription, we investigated the effects of transfecting rat liver with TTP constructs. We found that transfecting diabetic rats with TTP did not increase HMGR transcription but rather led to modest inhibition. We then investigated whether co-transfection with protein kinase B, hepatic form (AKT2), might lead to phosphorylation and result in activation of HMGR transcription. We found that this treatment resulted in near complete inhibition of transcription. Transfection with peroxisome proliferator-activated receptor g coactivator (PGC-1a) also inhibited HMGR transcription. These results show that although TTP is needed for activation of HMGR transcription, it cannot by itself activate this process. AKT2 and PGC-1a, which mediate the activation of gluconeogenic genes by insulin, exert the opposite effect on HMGR.
基金Supported by National Scientific and Technological Supporting Project(2008BADA4B04-09)Guangdong Province Scientific and Technological Project(2008A020100017)Guangdong Province Department of Finance Project[(2006)143]~~
文摘A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage(Brassica parachinensis Bailey).The results showed that all the application of these four amino acids could increase the yield of flowering Chinese cabbage,significantly raise the content of soluble sugar,and reduce the accumulation of nitrate.The applications of three other amino acids except alanine can increase the content of soluble proteins and decrease the accumulation of oxalic acid.However,the application of amino acid has insignificant influences on the SPAD number of chlorophyll,and causes the decrease of Vitamin C content.Meanwhile,the application of amino acid can improve the activity of nitrate reductase(NR) and glutamate dehydrogenase(GDH) as well.It shows that the application of amino acid is beneficial to improve ammonia metabolism,reduce the accumulation of nitrate and oxalic acid,increase the content of soluble sugar and soluble proteins,and improve the quality of flowering Chinese cabbage.