The expression of nitrate reductase in free-living Rhizobium sp.

1984 ◽  
Vol 30 (7) ◽  
pp. 890-893 ◽  
Author(s):  
Rachel Gollop ◽  
Yael J. Avissar
Keyword(s):  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Living Cells ◽  
Early Stationary Phase ◽  
Free Living ◽  
Rhizobium Sp ◽  
Stationary Cell

Nitrate reductase activity is expressed in bacteroids of peanut nodules but is absent in log phase cultures of Rhizobium sp. grown in the absence of nitrate. The assay of enzyme activity in free-living cells in vivo revealed a brief period of activity in early stationary phase and a recovery of activity upon prolonged microaerobic incubation of stationary cell suspensions. The expression of enzyme activity did not necessitate concurrent differentiation of rhizobia to bacteriods or the induction of nitrogenase.

scholarly journals Effect of lead on nitrate reductase activity and nitrate assimilation in pea leaves

2014 ◽  
Vol 57 (4) ◽  
pp. 457-463 ◽  
Author(s):  
S. K. Sinha ◽  
H. S. Srivastava ◽  
S. N. Mishra
Keyword(s):  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Organic Nitrogen ◽  
Reductase Activity ◽  
Total Organic Nitrogen ◽  
Intact Leaf ◽  
Leaf Tissues

The effect of Pb on nitrate reductase activity, protein, total organic nitrogen and on the chlorophyll content in excised and intact leaf tissues of <em>Pisum sativum</em> was examine. Enzyme activity assayed in vitro or in vivo in the excised leaves showed marked increase at lower concentrations of Pb while being inhibited at higher concentrations. In intact leaf tissues, the enzyme activity (in vivo or in vitro) was unaffected at lower concentrations but was inhibited at higher concentrations of Pb. Chlorophyll, carotenoids (non-nitrogenous pigments), soluble protein and organic nitrogen contents remained almost unaffected at all concentrations of Pb tested. It seems that nitrate reductase has a different response towards Pb pollution in this species, which is more tolerant to heavy metal pollution, especially Pb.

scholarly journals Evidence that the glutamine-stimulated loss of nitrate reductase protein from the yeast Candida nitratophila is not the result of inducer exclusion

1993 ◽  
Vol 295 (2) ◽  
pp. 611-615 ◽  
Author(s):  
C R Hipkin ◽  
D A Kau ◽  
A C Cannons
Keyword(s):  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
De Novo ◽  
Reductase Activity ◽  
Nitrogen Compounds ◽  
Similar Treatment ◽  
Inducer Exclusion ◽  
Reductase Mrna

Synthesis of nitrate reductase protein and increases in nitrate reductase activity occurred in cultures of the yeast Candida nitratophila when they were incubated in medium containing ammonium nitrate. Similar treatment with glutamine plus nitrate resulted in little increase in nitrate reductase activity, in cultures grown previously with reduced nitrogen compounds, and decreases in enzyme activity, in cultures adapted to nitrate. Labelling studies conducted in vivo revealed a rapid cessation of de novo nitrate reductase synthesis when glutamine was supplied to nitrate-adapted cultures in the presence of nitrate. Intracellular glutamine concentrations increased rapidly under these conditions and these cultures exhibited high glutamine: glutamate ratios. As nitrate was taken up in the presence of glutamine in these experiments, it is concluded that the glutamine-stimulated inhibition of nitrate reductase synthesis is a consequence of repression and rapid turnover of nitrate reductase mRNA and not inducer (nitrate) exclusion.

Acid phosphatase, alkaline phosphatase, and nitrate reductase activity of selected ectomycorrhizal fungi

1989 ◽  
Vol 67 (3) ◽  
pp. 750-753 ◽  
Author(s):  
Iwan Ho
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Acid Phosphatase ◽  
Nitrate Reductase ◽  
Phosphatase Activity ◽  
Ectomycorrhizal Fungi ◽  
Acid Phosphatase Activity ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Phosphatase Alkaline

Seventeen isolates, encompassing five genera and eight species of ectomycorrhizal fungi, were compared for acid phosphatase, alkaline phosphatase, and nitrate reductase activity. Isolates within species differed in enzyme activity and isozyme patterns by host specificity and site (as exemplified by the genus Suillus). Host and site may have affected phosphatase enzyme activity. Generally, the Douglas-fir associates, which dominate in mesic sites, have higher acid phosphatase activity than pine associates, which mostly occupy xeric sites; however, pine associates from mesic sites also have higher acid phosphatase activity (e.g., S. tomentosus). In four isolates of Amanita muscaria, the effect of site was also apparent. Two of them, which have significantly higher acid phosphatase activity than the others, were isolated from mesic sites. The isozyme pattern of the genus Suillus appeared to be separated by host groups. Other isolates with only one species also differed more or less by host groups. They shared at least one band within host groups, except for the two isolates of Paxillus involutus from different hosts. The P. involutus S-403 isolated from an orchard showed much higher nitrate reductase activity than all other isolates. No apparent differences in nitrate reductase activity were found between the other isolates.

SEASONAL PATTERNS OF DENITRIFICATION AND LEAF NITRATE REDUCTASE ACTIVITY IN A CORN FIELD

1978 ◽  
Vol 58 (2) ◽  
pp. 283-285 ◽  
Author(s):  
D. G. PATRIQUIN ◽  
J. C. MacKINNON ◽  
K. I. WILKIE
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
General Trend ◽  
Reductase Activity ◽  
Seasonal Patterns ◽  
Assay Procedure ◽  
Acetylene Blockage Technique ◽  
Acetylene Blockage ◽  
Leaf Nitrate

Denitrification in soil around the bases of corn stalks, determined by the "acetylene blockage technique," exhibited a general trend of decline from June to September. Leaf nitrate reductase activity, determined by an in vivo assay procedure, was low in June and July, and then exhibited a pronounced maximum at the time of tasselling.

Standardization of substrate and buffer concentrations for in-vivo nitrate reductase activity in Adenanthera microsperma leaves

2015 ◽  
Vol 38 (4) ◽  
pp. 309-311
Author(s):  
Priyanshu Sharma ◽  
S.P. Chaukiyal ◽  
Meenu Sengar
Keyword(s):  
Nitrate Reductase ◽  
Phosphate Buffer ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Buffer Solution ◽  
Substrate Solution ◽  
Substrate Concentrations

The combination of different substrate concentrations (0.05M, 0.10M, 0.15M, 0.20M and 0.25M, KNO3) with different pH of phosphate buffer (0.10 M and 0.20 M, KH2PO4 of the pH 7.0, 7.5, 7.6, 7.7, and 7.8) solutions were tried for in-vivo nitrate reductase activity of Adenanthera microsperma leaves. Maximum nitrate reductase activity was observed in the combination of buffer solution (0.20M KH2PO4) having pH 7.7 and substrate solution 0.20 M concentration.

Nitrate Reductase Profiles in Leaves of Tall Morningglory Seedlings

Weed Science ◽  
1973 ◽  
Vol 21 (6) ◽  
pp. 561-564 ◽  
Author(s):  
Donald S. Galitz
Keyword(s):  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Leaf Growth ◽  
Leaf Tissue ◽  
Plant Leaf ◽  
Ipomoea Purpurea ◽  
True Leaf

Nitrate reductase activity of seed leaves and the first three true leaves of tall morningglory [Ipomoea purpurea (L.) Roth] was shown to increase rapidly initially then gradually decrease. The greatest level of reductase activity of each true leaf was reached at the fourth to fifth day after unfolding. A subsequent leveling off of enzyme activity corresponded to the acceleration of leaf growth. Leaf nitrates were correlated with enzyme activity. The sum of leaf activities was used to estimate the total reductive capacity of the plant leaf tissue at each sampling date.

Differential effects of ozone on in vivo nitrate reduction in soybean cultivars. I. Response to exogenous sugars

1978 ◽  
Vol 56 (13) ◽  
pp. 1540-1544 ◽  
Author(s):  
Albert C. Purvis
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Foliar Injury ◽  
Glycolytic Intermediates ◽  
Glycine Max L ◽  
Growth Chambers ◽  
Visible Foliar Injury

Two cultivars of soybeans (Glycine max (L.) Merr.) differing widely in their resistance to ozone were exposed to 0.5 μl/ℓ ozone for 2 h in growth chambers. In vivo nitrate reduction was depressed by more than 50% in the primary leaves of Dare, the ozone-sensitive cultivar, but was not significantly altered in Hood, the ozone-resistant cultivar. Sucrose, up to 1.5% (w/v), added to excised seedlings of the Dare cultivar during exposure to ozone eliminated the ozone depression of in vivo nitrate reductase activity and also reduced foliar injury. Addition of two glycolytic intermediates, glyceraldehyde-3-phosphate and fructose-1,6-diphosphate, to the infiltration medium recovered some in vivo nitrate reduction in treated Dare leaves. The levels of extractable nitrate reductase and glyceraldehyde-3-phosphate dehydrogenase in the primary leaves of both cultivars were unaltered by ozone fumigations. These observations led to the conclusion that ozone depression of in vivo nitrate reduction is not due to ozone inactivation of nitrate reductase or of the enzymes coupling nitrate reduction to glycolysis, but may be caused by an inadequate supply of photosynthetic sugars. It was also noted that ozone depression of in vivo nitrate reduction only occurred with treatments which subsequently caused the development of visible foliar injury.

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