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21.
Metabolic Responses Induced by Serial Harvesting of Alfalfa Pasture Established on Amended Acid Soil
《Communications in Soil Science and Plant Analysis》2012,43(9-10):1281-1301
Abstract Alfalfa pasture has not been sustainable on the coastal plain of the United States because of its intolerance to soil acidity. This study examined the responses of alfalfa metabolism to differential amendments of acid soil and to serial harvesting. The soil was spatially amended with different quantities of flue gas desulfurization sludge and gypsum after liming to pH 7. The serial harvests oscillated the RNA synthetic activity of glutamate dehydrogenase (GDH) from an oxidized to a reduced state irrespective of the soil amendments. The amplitudes of the redox cycles changed from one harvest to the next, thus demonstrating improved regrowth persistence. The chlorophyll, hexose, nucleotide, and protein contents, and the fructose‐1, 6‐bisphosphatase activity, decreased and fluctuated inconsistently in the successive cuttings. Consideration of the metabolic responses per harvest showed that the alfalfa had optimized saccharide metabolism in the first harvest, optimized RNA metabolism in the second harvest, optimized saccharide and RNA metabolism in the third harvest, and depressed saccharide metabolism in the fourth harvest, thereby optimizing the regrowth potential of the alfalfa pasture. Sustainability of the pasture was conferred by the coordinate compensatory regulation of metabolism in response to the synergistic interaction between the differential amendments and the nitrogen (N) nutrient excreted by the alfalfa into the soil. 相似文献
22.
葡萄糖脱氢酶（GDH）和吡咯喹啉醌（PQQ）对溶磷微生物溶解无机磷具有重要作用。本研究为了探讨甘蔗内生固氮菌变栖克雷伯菌（Klebsiella variicola）DX120E的溶磷机制,从该菌中克隆溶磷基因GDH和pqqE的ORF,并进行了生物信息学分析,同时还研究了该菌对不同磷源的利用能力。结果表明：克隆得到甘蔗内生固氮菌Klebsiella variicola DX120E GDH和pqqE基因的ORF分别为2373 bp和1143 bp,编码氨基酸分别为790个和380个。生物信息学分析结果表明,GDH蛋白为稳定蛋白,pqqE蛋白为不稳定蛋白。GDH蛋白是一个与细胞信号传导有关的膜受体蛋白,具有PQQ_membr_DH、PQQ_mGDH功能域和PQQ_DH_like超家族蛋白结构;pqqE基因编码的蛋白是胞内蛋白,含有1个PQQ_syn_pqqE功能域和Radical SAM超家族蛋白的结构。内生固氮菌Klebsiella variicola DX120E对不同磷源的利用和GDH和pqqE基因在不同磷源培养时的qRT-PCR分析表明,该菌对不同磷源的溶磷能力表现为FePO4>AlPO4>Ca3(PO4)2,且溶解FePO4的能力与溶解Ca3(PO4)2、AlPO4等难溶磷源的差异均显著（P<0.05）。在几种磷源条件下,GDH和pqqE基因相对表达量均增加,且2个基因的表达量变化趋势一致。GDH和pqqE基因在以FePO4为磷源条件下的表达量与以Ca3(PO4)2为磷源的表达量差异显著（P<0.05）。本研究可为进一步研究内生固氮菌与甘蔗的互作和溶磷机制提供参考。 相似文献
23.
斑节对虾谷氨酸脱氢酶基因的克隆及氨氮胁迫对其时空表达的影响 总被引：1，自引：1，他引：0
采用cDNA末端快速扩增技术(rapid amplification of cDNA ends, RACE)获得了斑节对虾(Penaeus monodon)谷氨酸脱氢酶基因(PmGDH)的cDNA序列。该序列全长2386 bp,开放阅读框(ORF)为1677 bp,3?非编码区(UTR)为688 bp,包括含有27个碱基的poly(A)尾,5?非编码区(UTR)为21 bp。ORF可编码558个氨基酸,预测分子量为61.837 kD,理论等电点为6.57。序列含有ELFV dehydrog N与NAD bind 1 Glu DH两个保守结构域,37个磷酸化位点,3个糖基化位点。通过同源性、相似性以及系统进化树分析,斑节对虾的GDH基因与凡纳滨对虾(Litopenaeus vannamei)GDH基因的同源性和相似性最高,并与其聚为一支。采用荧光定量的方法研究了PmGDH基因在斑节对虾不同组织、氨氮胁迫过程中差异表达情况。结果表明, PmGDH的mRNA在各组织中都有表达,其中,在肌肉组织中表达量最高,其次为眼柄神经,在血淋巴与肠组织中表达量最低。96 h氨氮胁迫后,荧光定量PCR分析结果表明PmGDH在肝胰腺和鳃组织中的表达与对照组相比都具有显著差异(P<0.05),都具有不同程度的表达上调。表明PmGDH在氨氮代谢方面具有重要的作用,参与了斑节对虾机体的急性氨氮胁迫应答反应。 相似文献
24.
通过对对数生长期细胞的异柠檬酸裂解酶（ICL）、异柠檬酸脱氢酶（ICDH）、α-酮戊二酸脱氢酶（ODH）和谷氨酸脱氢酶（GDH）的分析以及对细胞L-谷氨酸产生量和发酵残糖的综合分析,发现由于乙醛酸循环关键酶ICL的缺失,L-谷氨酸产生量大幅下降,说明乙醛酸循环是谷氨酸棒杆菌中的主要回补途径,L-谷氨酸合成需要乙醛酸循环。在保证乙醛酸循环回补功能的前提下,提高ICDH活性,减弱ODH活性,有利于L-谷氨酸的合成。 相似文献
25.
Muhammad Ashraf Sher Muhammad Shahzad Muhammad Imtiaz Muhammad Shahid Rizwan 《Journal of plant nutrition》2018,41(8):1065-1081
Nitrogen (N) metabolism is of great economic importance because it provides proteins and nucleic acids which in turn control many cellular activities in plants. Salinity affects different steps of N metabolism including N uptake, NO3? reduction, and NH4+ assimilation, leading to a severe decline in crop yield. Major mechanisms of salinity effects on N metabolism are salinity-induced reductions in water availability and absorption, disruption of root membrane integrity, an inhibition of NO3? uptake by Cl?, low NO3? loading into root xylem, alteration in the activities of N assimilating enzymes, decrease in transpiration, and reduction in relative growth rate which results in a lower N demand. However, the effects of salinity on N metabolism are multifaceted and may vary depending on many plant and soil factors. The present review deals with salinity effects on N metabolism in plants, emphasizing on the activities of N metabolizing enzymes in a saline environment. 相似文献
26.
【目的】克隆桑树的谷氨酸脱氢酶基因GDH,了解其结构、组织特异性表达以及调控特点,并获得桑树谷氨酸脱氢酶蛋白,为进一步研究谷氨酸脱氢酶（glutamate dehydrogenase,GDH）在桑树氮代谢过程中的功能奠定基础,也为多年生木本植物的GDH研究提供参考。【方法】根据川桑基因组数据库搜索GDH同源序列设计引物,以杂交桑品种桂桑优62号（M. atropurpurea Roxb.）cDNA为模板,通过RT-PCR克隆获得MaGDHs。利用NCBI上BLAST和CDD进行氨基酸序列比对和保守结构域分析;利用Expasy在线软件对MaGDH氨基酸组成、分子量、等电点进行分析;采用MEGA 5.0软件构建系统进化树;通过qRT-PCR检测试管苗在不同浓度的蔗糖、铵盐、激素（6-BA）状态下MaGDHs的表达量,用StepOne Software V2.1软件根据2-△△Ct法进行基因相对表达量分析。以pET-28a(+)、pET-32a(+)、pCold-TF为载体构建MaGDH的融合蛋白重组质粒并转入到大肠杆菌中进行表达。【结果】成功获得2个MaGDHs,序列全长均为1 236 bp,编码411个氨基酸,含一个开放阅读框,分别命名为MaGDH1和MaGDH2。MaGDH1蛋白质的分子量为44.1 kD,理论等电点为5.84,MaGDH2蛋白质的分子量为44.2 kD,理论等电点为6.68。MaGDHs氨基酸序列含有9个外显子,8个内含子,具有线粒体转移肽、Glu/a-KG结合域和NAD(P)结合域,与川桑同源性均为99%,与双子叶植物同源性为90%左右,与单子叶植物的同源性为85%左右。重组蛋白MaGDHs以包涵体的形式在大肠杆菌BL21（DE3）中表达,经过纯化和复性后获得了具有活性的酶蛋白,酶活性以pET-28a(+)-MaGDH1重组蛋白最高,为10.07 nmol·min-1·mL-1。MaGDHs的表达具有组织特异性,在桑花中表达量最高,其次是嫩叶,在果实中几乎不表达。MaGDHs的表达受到蔗糖、NH4+和6-BA的调控。随着蔗糖浓度的增加,MaGDHs表达量增加;过量的NH4+促进MaGDH1的表达,而没有NH4+的情况下,MaGDHs也有表达;细胞分裂素对MaGDHs的表达是先抑制后促进,MaGDH1在24 h后表达增强,MaGDH2在48 h后表达增强。【结论】从桂桑优62号中获得了两个MaGDHs,分别编码β和α亚基。不同载体的重组蛋白酶活性存在差异。MaGDHs的表达具有组织特异性,在桑树生长旺盛的组织中表达量较高。过量NH4+促进MaGDH1表达;MaGDH1响应激素促进表达比MaGDH2早。 相似文献