The intracellular location of nitrogen metabolism enzymes in Pisum arvense L. roots

The time course changes of nitrate assimilation enzymes and their distribution has been studied in Pisum arvense roots. The results indicate that nitrate reductase (EC 1.6.6.2) and glutamine synthetase (EC 6.3.1.2) are present in the soluble fraction, and nitrite reductase (EC 1.6.6.4) and glutamate synthase (EC 2.6.1.53) are localised in the plastids. The results show that the glutamine synthetase/glutamate synthase system is the major pathway of ammonium incorporation in NO3-supplied Pisum arvense roots and glutamate dehydrogenase plays a lesser role.

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The roles of glutamate dehydrogenase, glutamine synthetase and three forms of glutamate synthase on nitrogen assimilation in various organs of Pisum arvense L.

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1991.022 ◽

2014 ◽

Vol 60 (3-4) ◽

pp. 295-302

Author(s):

Genowefa Kubik-Dobosz

Keyword(s):

Glutamine Synthetase ◽

Glutamate Dehydrogenase ◽

Nitrogen Assimilation ◽

Decisive Role ◽

Glutamate Synthase ◽

Pisum Arvense ◽

Age Dependent ◽

The Individual

The activities of GDH, GS and three forms of GOGAT (NADH, NADPH or ferredoxin-dependent) were studied in the leaves, stems and roots of the Pisum arvense. GS and the individual forms of GOGAT dominated in the leaves of 7 day-old plants which were taking up NO3- or NH4+ ions, while NADH-GDH dominated in the roots of these plants. In comparison with HNO3- , NH4+ ions stimulated the activity of most of the enzymes of the GS/GOGAT and GDH pathways in stems and roots, while in and leaves this effect was age-dependent. The Fd-GOGAT located in leaves and stems was not regulated by NH4+ , which indicates that this enzyme is not likely to be directly involved in the assimilation of NH4+ ions that have been taken up. The obtained data indicate that at lower tissue NH4+ concentration a decisive role in nitrogen assimilation in leaves and stems is played by the GS/GOGAT pathway, while in the roots-by GDH and in less degree by GS, GOGAT. High amounts of accumulated NH4+ ions set off a detoxication mechanism which includes NADH-GDH, common to all tissues. Only in 7 day-old leaves did the detoxication of NH4+ take place with the involvement of NADH-GOGAT and NADPH-GOGAT.

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The localization of nitrite reductase, glutamate synthase and malate metabolism enzymes in Pisum arvense L. roots

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1985.008 ◽

2014 ◽

Vol 54 (1) ◽

pp. 85-93

Author(s):

Genowefa Kubik-Dobosz ◽

Grażyna Kłobus

Keyword(s):

Nitrite Reductase ◽

Malic Enzyme ◽

Acid Metabolism ◽

Glutamate Synthase ◽

Sucrose Density Gradient ◽

Pyridine Nucleotides ◽

Pisum Arvense ◽

Metabolism Enzymes ◽

Malic Enzyme Activity ◽

Malate Metabolism

Centrifugation of a homogenate made from Pisum arvense L. roots in a sucrose density gradient enabled the separation of the plastid fraction from mitochondria and microsomes. The presence of nitrite reductase and glutamate synthase was demonstrated in the plastids. Malic enzyme activity was not linked with any organelle fraction and was found only in the cytosol. High malate dehydrogenase activity was found in the mitochondria fraction, although its activity was also determined in plastids. The results suggest that malic acid metabolism in plastids may be the source of reduced pyridine nucleotides for reactions catalysed by nitrite reductase and glutamate synthase.

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Time course changes of fibrous structure within connective tissue. Why do "wrinkles" or "sags" develop with age?

Nishi Nihon Hifuka ◽

10.2336/nishinihonhifu.51.1093 ◽

1989 ◽

Vol 51 (6) ◽

pp. 1093-1100 ◽

Cited By ~ 1

Author(s):

SHUHEI IMAYAMA

Keyword(s):

Connective Tissue ◽

Time Course ◽

Fibrous Structure ◽

Course Changes

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Histopathological study of time course changes in inter-renal aortic banding-induced left ventricular hypertrophy of mice

International Journal of Experimental Pathology ◽

10.1111/j.1365-2613.2006.00514.x ◽

2006 ◽

Vol 88 (1) ◽

pp. 31-38 ◽

Cited By ~ 9

Author(s):

Hiroyuki Higashiyama ◽

Masaki Sugai ◽

Hirotaka Inoue ◽

Kaori Mizuyachi ◽

Hiroshi Kushida ◽

...

Keyword(s):

Left Ventricular Hypertrophy ◽

Ventricular Hypertrophy ◽

Time Course ◽

Left Ventricular ◽

Histopathological Study ◽

Aortic Banding ◽

Course Changes

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Time course changes of vasopressin-induced enlargement of the rat intrastrial space and the effects of a vasopressin type 2 antagonist

Acta Oto-Laryngologica ◽

10.1080/00016480802419115 ◽

2009 ◽

Vol 129 (7) ◽

pp. 709-715 ◽

Cited By ~ 12

Author(s):

Masahiko Nishimura ◽

Akinobu Kakigi ◽

Taizo Takeda ◽

Teruhiko Okada ◽

Katsumi Doi

Keyword(s):

Time Course ◽

Course Changes

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Cerebral oxygenation changes in response to motor stimulation

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.3.1174 ◽

1996 ◽

Vol 81 (3) ◽

pp. 1174-1183 ◽

Cited By ~ 165

Author(s):

H. Obrig ◽

C. Hirth ◽

J. G. Junge-Hulsing ◽

C. Doge ◽

T. Wolf ◽

...

Keyword(s):

Time Course ◽

Near Infrared ◽

Cerebral Oxygenation ◽

Motor Task ◽

Hemoglobin Concentration ◽

Hemodynamic Response ◽

Blood Oxygenation ◽

Initial Increase ◽

Cerebral Hemodynamic ◽

Course Changes

We studied cerebral hemodynamic response to a sequential motor task in 56 subjects to investigate the time course and distribution of blood oxygenation changes as monitored by near-infrared spectroscopy (NIRS). To address whether response is modulated by different performance velocities, a group of subjects (n = 12) was examined while performing the motor task at 1, 2, and 3 Hz. The results demonstrate that 1) the NIRS response reflects localized changes in cerebral hemodynamics, 2) the response, consisting of an increase in oxygenated hemoglobin concentration [oxy-Hb] and a decrease in deoxygenated hemoglobin concentration ([deoxy-Hb]), is lateralized and increases in amplitude with higher performance rates, and 3) changes in [oxy-Hb] and [deoxy-Hb] differ in time course. Changes in [oxy-Hb] are biphasic, with a fast initial increase and a pronounced poststimulus undershoot. The stimulus-associated decrease in [deoxy-Hb] is monophasic, and response latency is greater. We conclude that NIRS is able to detect even small changes in cerebral hemodynamic response to functional stimulation.

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