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1

Glutamate dehydrogenase and glutamine synthetase activities during the development of triticale grains

100%

Kwinta J., Bartoszewicz K., Bielawski W.

Acta Physiologiae Plantarum

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1999

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tom 21

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nr 3

2

Purification and partial characterization of glutamine synthetase isoforms from Triticale seedlings

100%

Bielawski W.

Acta Biochimica Polonica

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1994

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tom 41

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nr 4

Two isoforms of glutamine synthetase (EC 6.3.1.2), cytoplasmic (GSi) and chloroplastic (GSi) were isolated from shoots of 14-day-old Triticale seedlings, and purified 260-fold and 248-fold, respectively. Specific activities of the two preparations were 35.1 and 33.5 nmol x min-1 per mg of protein, respectively. Both crude extracts and homogeneous GSi and GS2 preparations required divalent metal ions (Mg2+, Mn2+, Co2+) for their activities. Mg2+ was the most effective activator, the highest activity of GSi being reached at 5 mM, and that of GS2 at 20 mM MgCl2- The optimum pH for the two isoforms showed large differences, dependent also on the kind of divalent ion. Molecular masses of GSi and GS2 were 305000 Da and 385200 Da, respectively. It seems that native protein of GSi is built from eight identical subunits of Mm 38000 Da and that of GS2 of the same number of subunits but of Mm of about 48000 Da. Proteins of GS isoforms differed significantly in their amino-acid composition.

3

Immunofluorescence of bulk isolated rat astrocytes with anti-GFAP and anti-GS sera

86%

Weinrauder H., Albrecht J.

Bulletin of the Polish Academy of Sciences. Biological Sciences

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1989

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tom 37

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nr 10-12

4

The effect of Cu2plus on uptake and assimilation of ammonium by cucumber seedlings

86%

Burzynski M., Buczek J.

Acta Physiologiae Plantarum

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1997

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tom 19

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nr 1

The ammonium uptake by cucumber seedlings was estimated from ammonium ions depletion in an uptake solution. The uptake of NH ⁺₄ was decreased by about 60 % after one hour and by about 90 % after two hours of 100 µM Cu²⁺ treatment. On the contrary the accumulation of ammonium in roots of Cu²⁺-treated seedlings at the same time was higher than in the control. Cu²⁺ in the concentration inhibiting NH ⁺₄ absorption during one hour inhibited also glutamine synthetase (GS) (EC 6.3.1.2) and NADH-glutamate dehydrogenase (NADH-GDH) (EC 1.4.1.2) activities both localized in the roots of seedlings. After one hour and at least up to the 4th hour Cu²⁺ accumulated mainly in roots (95 %). It was probably the reason of the GS activity in cotyledons of seedling treated with Cu²⁺ that it was at the same level as in the control. NADH-GDH activity in cotylcdons after one hour of the Cu²⁺ treatment was lower than in the control but the influence of Cu²⁺ action on the activity of this enzyme in roots was by far stronger. 100 µM Cu²⁺ did not affect the activities of both enzymes in in vitro experiments. Copper added into the incubation medium in 1000 µM concentration decreased GS activity, but still did not change NADH-GDH activity. These results suggested the indirect Cu²⁺ action on the investigated enzymes in in vivo experiments. However, no substantial effect on enzyme activities extracted from control plants was observed after the addition of the extract from Cu²⁺-treated plants into the incubation medium. The data suggest that the influence of Cu²⁺ on uptake and assimilation of ammonium may be connected not only with changes of plasma membrane properties in the root cells of Cu²⁺ treated seedlings but also with Cu²⁺ action on two major enzymes involved in NH ⁺₄ assimilation: glutamate synthetase and NADH-glutamate dehydrogenase.

5

Effects of salinity stress on the activity of glutamine synthetase and glutamate dehydrogenase in triticale seedlings

86%

Kwinta J., Cal K.

Polish Journal of Environmental Studies

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2005

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tom 14

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nr 1

The effect of salinity on the activity of glutamine synthetase (GS EC 6.3.1.2.) and glutamate dehydrogenase (NAD(P)H-GDH EC 1.4.1.2-4) in shoots and roots of triticale seedlings was investigated. Stressed plants were cultured hydroponically on the 100 mM NaCl-enriched medium for 7 days and the physiological responses were measured. Apart from changes in morphology of plants, alterations in GS and NAD(P)H-GDH activity were reported. GS activity in roots of stressed plants grew slightly and in shoots it decreased by approx. 30% as compared to control plants. In shoots of both control and stressed plants two GS isoforms were detected: cytoplasmic (GS1) and chloroplastic (GS2). A drop in total GS activity in shoots of NaCl-treated plants was due to the drop in activity of GS2 isoform. The activity of GS1 grew slightly under saline stress. After staining of gels for GDH activity, no changes in isoforms were noted as compared with the control plants.

6

Glutamine synthetase in Lupinus luteus. Identification and preliminary characterization of nodule-specific cDNA clone

72%

Boron L., Szczyglowski K., Konieczny A., Legocki A. B.

Acta Biochimica Polonica

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1989

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tom 36

|

nr 3-4

7

Effect of some compounds on glutamine synthetase isoform activity from Triticale seedling leaves

72%

Bielawski W.

Acta Physiologiae Plantarum

|

1994

|

tom 16

|

nr 4

8

Ontogenic variation of nodulation, nitrogen fixation and nitrogen assimilation in lentil [Lens culinaris Medic]. II. Nitrogenase, nitrate reductase and glutamine synthetase activities

72%

Awan M. F. M.

Acta Physiologiae Plantarum

|

1994

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tom 16

|

nr 4

9

Glutamine synthetase and glutamate dehydrogenase in cadmium-stressed triticale seedlings

72%

Kwinta J., Kozlik D.

Acta Physiologiae Plantarum

|

2006

|

tom 28

|

nr 4

The studies were performed on young triticale seedlings grown on a mineral medium containing 5 mM NO3- as the nitrogen source, with the addition of 0.5 mM CdCl2. It was determined that cadmium ions accumulated mainly in the plant roots. Decreases in nitrate concentrations both in the roots and shoots of seedlings, as well as decreases in soluble protein contents with simultaneous increases in endopeptidase activity were also observed. Both in roots and shoots significant decreases in glutamic acid were noted. Toxic cadmium ion accumulation in seedlings significantly modified activity of primary nitrogen assimilating enzymes, i.e. glutamine synthetase (GS, EC 6.3.1.2) and glutamate dehydrogenase (GDH, EC 1.4.1.2). There was a significant decrease in GS activity both in roots and in shoots of the stressed plants, in compari son to plants grown without cadmium. In shoots of the control plants and plants subjected to stress two GS isoforms were discovered: cytoplasmatic (GSi) and chloroplastic (GS2). Substantial decreases in total glutamine synthetase activity in green parts of seedlings, occurring under stress conditions, result from dramatic decrease in GS2 activity (by 60 % in relation to the control plants); despite simultaneous increases in the cytoplasmatic isoform (GS1) activity by approx. 96 %. Cadmium ions accumulating in roots and shoots of seedlings not only increased GDH activity, but also modified its coenzymatic specificity.

10

Rat cerebral mitochondrial glutaminase activity is unaffected by moderate hyperammonemia in two models

72%

Albrecht J., Hilgier W., Faff L.

Acta Neurobiologiae Experimentalis

|

1996

|

tom 56

|

nr 2

11

Effect of nickel on ammonium assimilating enzymes in wheat shoots

58%

Gajewska E., Bergier K., Wielanek M., Mazur J., Sklodowska M.

Zeszyty Problemowe Postępów Nauk Rolniczych

|

2008

|

tom 524

Effects of two Ni concentrations (50 and 100 µM) on growth, Ni accumulation as well as the activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) were studied in shoots of wheat seedlings. Exposure to Ni caused rapid accumulation of this metal in the shoots accompanied by a substantial decrease in the length and fresh weight of these organs. Both aminating (NADH-GDH) and deaminating (NAD-GDH) glutamate dehydrogenase activities were significantly influenced by Ni stress, while GS activity did not change in response to Ni application. The activity of NADH-GDH showed an increase at the end of the experiment and 7 days after Ni treatment it was 68% and 76% higher than in the control, at 50 and 100 µM Ni, respectively. NAD-GDH activity after 1 and 4 days of exposure to a higher concentration of Ni was reduced by 24% and 37%, respectively. However, on the 7th day the activity of this enzyme was enhanced by 150% and 72% over the control level, at 50 and 100 µM Ni, respectively. The obtained results suggest that GDH can play an important role in response of wheat seedlings to Ni toxicity.

12

Distribution of glutamine synthetase isoforms in Triticale seedling leaves

58%

Bielawski W.

Acta Physiologiae Plantarum

|

1993

|

tom 15

|

nr 4

13

Effects of UV-B irradiation on growth, survival, pigmentation and nitrogen metabolism enzymes in cyanobacteria

58%

Sinha R. P., Kumar H. D., Kumar A., Hader D. P.

Acta Protozoologica

|

1995

|

tom 34

|

nr 3

14

The protective role of astroglia in the early period of experimental lead toxicity in the rat

58%

Struzynska L.

Acta Neurobiologiae Experimentalis

|

2000

|

tom 60

|

nr 2

Although the clinical manifestations of lead (Pb) neurotoxicity are documented, the subcellular mechanisms of its action are still an open question. The purpose of this study was to assess the function of nerve ending particles after acute lead exposure and to investigate whether it exerts a toxic effect on astroglial functions. The studies were performed using the rodent model of acute lead toxicity. Cellular fractions were used in biochemical measurements - synaptosomes and glial plasmalemmal vesicles (GPV). Since a procedure for the isolation of the fraction of astroglial origin has been developed, it becomes possible to investigate lead-astroglia interactions after in vivo exposure. It is of importance because most of the studies concerning lead toxicity were performed using astroglial culture systems. It was found that the uptake of glutamate (Glu) to the synaptosomes was lowered and KCl-dependent release was increased, suggesting the impairment of glutamatergic transmission leading to the elevation of extracellular amino acid concentration. In contrast, glutamate uptake to the GPV fraction was significantly elevated. The activity of the marker enzyme - glutamine synthetase (GS) was also significantly increased in the GPV fraction. The activation of glial functions suggest a regulatory role for these cells in the early period of acute lead toxicity.

Ograniczanie wyników

Glutamate dehydrogenase and glutamine synthetase activities during the development of triticale grains

Purification and partial characterization of glutamine synthetase isoforms from Triticale seedlings

Immunofluorescence of bulk isolated rat astrocytes with anti-GFAP and anti-GS sera

The effect of Cu2plus on uptake and assimilation of ammonium by cucumber seedlings

Effects of salinity stress on the activity of glutamine synthetase and glutamate dehydrogenase in triticale seedlings

Glutamine synthetase in Lupinus luteus. Identification and preliminary characterization of nodule-specific cDNA clone

Effect of some compounds on glutamine synthetase isoform activity from Triticale seedling leaves

Ontogenic variation of nodulation, nitrogen fixation and nitrogen assimilation in lentil [Lens culinaris Medic]. II. Nitrogenase, nitrate reductase and glutamine synthetase activities

Glutamine synthetase and glutamate dehydrogenase in cadmium-stressed triticale seedlings

Rat cerebral mitochondrial glutaminase activity is unaffected by moderate hyperammonemia in two models

Effect of nickel on ammonium assimilating enzymes in wheat shoots

Distribution of glutamine synthetase isoforms in Triticale seedling leaves

Effects of UV-B irradiation on growth, survival, pigmentation and nitrogen metabolism enzymes in cyanobacteria

The protective role of astroglia in the early period of experimental lead toxicity in the rat