Effect of nitrogen starvation on ammonium-inhibition of nitrogenase activity in Azotobacter chroococcum

1988 ◽  
Vol 149 (6) ◽  
pp. 481-484 ◽  
Author(s):  
Francisco J. Cejudo ◽  
Antonio Paneque
Keyword(s):  
Nitrogen Starvation ◽  
Nitrogenase Activity ◽  
Azotobacter Chroococcum ◽  
Ammonium Inhibition

scholarly journals Molybdenum and vanadium nitrogenases of Azotobacter chroococcum. Low temperature favours N2 reduction by vanadium nitrogenase

1988 ◽  
Vol 256 (2) ◽  
pp. 429-432 ◽  
Author(s):  
R W Miller ◽  
R R Eady
Keyword(s):  
Low Temperature ◽  
Electron Flux ◽  
Specific Activity ◽  
Nitrogenase Activity ◽  
Azotobacter Chroococcum ◽  
Effect Of Temperature ◽  
High Electron ◽  
Mofe Protein ◽  
Fe Protein ◽  
Vanadium Nitrogenase

A comparison of the effect of temperature on the reduction of N2 by purified molybdenum nitrogenase and vanadium nitrogenase of Azotobacter chroococcum showed differences in behaviour. As the assay temperature was lowered from 30 degrees C to 5 degrees C N2 remained an effective substrate for V nitrogenase, but not Mo nitrogenase, since the specific activity for N2 reduction by Mo nitrogenase decreased 10-fold more than that of V nitrogenase. Activity cross-reactions between nitrogenase components showed the enhanced low-temperature activity to be associated with the Fe protein of V nitrogenase. The lower activity of homologous Mo nitrogenase components, although dependent on the ratio of MoFe protein to Fe protein, did not equal that of V nitrogenase even under conditions of high electron flux obtained at a 12-fold molar excess of Fe protein.

scholarly journals The vanadium nitrogenase of Azotobacter chroococcum. Purification and properties of the Fe protein

1988 ◽  
Vol 256 (1) ◽  
pp. 189-196 ◽  
Author(s):  
R R Eady ◽  
T H Richardson ◽  
R W Miller ◽  
M Hawkins ◽  
D J Lowe
Keyword(s):  
Nitrogenase Activity ◽  
Azotobacter Chroococcum ◽  
Blue Staining ◽  
Visible Range ◽  
Coomassie Blue Staining ◽  
Reduction Activity ◽  
Fe Protein ◽  
Coomassie Blue ◽  
Purification And Properties ◽  
Vanadium Nitrogenase

1. Nitrogenase activity of a strain of Azotobacter chroococcum lacking the structural genes of Monitrogenase (nifHDK) was associated with a V + Fe-containing protein and an Fe-containing protein [Robson, Eady, Richardson, Miller, Hawkins & Postgate (1986) Nature (London) 322, 388-390; Eady, Robson, Richardson, Miller & Hawkins (1987) Biochem. J. 244, 197-207]. 2. The Fe protein was purified to homogeneity by the criterion of Coomassie Blue staining after electrophoresis in 10% or 17% (w/v) polyacrylamide gels in the presence of SDS. One type of subunit, of Mr 32,000 +/- 2000, was found. 3. The native protein had an Mr of 62,500 +/- 2500 and contained approximately 4 Fe atoms and 4 acid-labile sulphide groups per molecule. The amino acid composition was similar to those of other purified Fe proteins, and, characteristically, tryptophan was absent. The specific activities (nmol of protein/min per mg of protein) when assayed under optimum conditions with the VFe protein from this strain were 1211 for H2 evolution under Ar, 337 for NH3 from N2 formation and 349 for C2H2 reduction. Activity of the Fe protein was O2-labile with a t1/2 of 36 s in air. At low temperatures the dithionite-reduced protein exhibited e.p.r. signals consistent with the presence of both S = 1/2 and S = 3/2 spin states. These signals were similar to those given by other nitrogenase Fe proteins, as were the changes in their line shape that occurred in the presence of MgATP or MgADP. The absorbance spectra showed that an increase in absorption occurred in the visible range on reversible oxidation of the dithionite-reduced protein. The oxidized-minus-reduced epsilon 420 was 6000 M-1.cm-1.

scholarly journals Molecular Evolution of the Negative Regulatory Gene (NIFL) from Azotobacter Chroococcum and its Nitrogenase Activity

2018 ◽  
Vol 15 (2) ◽  
pp. 397-406
Author(s):  
Gothandapani Sellamuthu ◽  
Prabha Shankar ◽  
Sekar Soundarapandian ◽  
Sangeeta Paul ◽  
Jasdeep C. Padaria
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Source ◽  
Genetic Manipulation ◽  
Nitrogenase Activity ◽  
Inorganic Nitrogen ◽  
Regulatory Gene ◽  
Azotobacter Chroococcum ◽  
Inorganic Nitrogen Source ◽  
Plant Growth Promoting ◽  
Growth Promoting

Two isolates of Azotobacter chroococcum (A. chroococcum CBD15 and A. chroococcum W5), were characterized for their atmospheric nitrogen fixing efficiency and ability to produce plant growth promoting hormone. The isolates, A. chroococcum CBD15 and A. chroococcum W5, were observed the production of Indole acetic acid (IAA) and nitrogen fixation in the absence of any inorganic nitrogen source. The ability nitrogen fixation was estimated by acetylene reduction studies revealed that A. chroococcum CBD15 produced 693.3 nmole C2H4 h-1 mg-1 whereas A. chroococcum W5 produced 523.4 nmole C2H4 h-1 mg-1. Nitrogenase activity of both the isolates was reduced when grown in media containing nitrogen source (ammonia or urea), in comparison to media lacking any nitrogen source. The nifL gene, which is one of the most important regulatory gene of nitrogen fixation pathway, was isolated from A. chroococcum CBD15 and A. chroococcum W5. Sequence analysis revealed that both nifL gene sequences have maximum homology with nifL gene of A. vinelandii and Pseudomonas oryzae respectively. The genetic manipulation of nifL gene of A. chrococcum will lead to development of an efficient bioinoculant for sustainable agriculture.

scholarly journals Rhamnolipid Enhances the Nitrogen Fixation Activity of Azotobacter chroococcum by Influencing Lysine Succinylation

2021 ◽  
Vol 12 ◽  
Author(s):  
Jin Li ◽  
Hu Pan ◽  
Hui Yang ◽  
Chong Wang ◽  
Huhu Liu ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Crop Production ◽  
Nitrogenase Activity ◽  
Tricarboxylic Acid Cycle ◽  
Azotobacter Chroococcum ◽  
Mechanistic Study ◽  
Nitrogen Fixation Activity ◽  
Lysine Succinylation ◽  
Fixation Activity ◽  
Proteomic Approach

The enhancement of nitrogen fixation activity of diazotrophs is essential for safe crop production. Lysine succinylation (KSuc) is widely present in eukaryotes and prokaryotes and regulates various biological process. However, knowledge of the extent of KSuc in nitrogen fixation of Azotobacter chroococcum is scarce. In this study, we found that 250 mg/l of rhamnolipid (RL) significantly increased the nitrogen fixation activity of A. chroococcum by 39%, as compared with the control. Real-time quantitative reverse transcription PCR (qRT-PCR) confirmed that RL could remarkably increase the transcript levels of nifA and nifHDK genes. In addition, a global KSuc of A. chroococcum was profiled using a 4D label-free quantitative proteomic approach. In total, 5,008 KSuc sites were identified on 1,376 succinylated proteins. Bioinformatics analysis showed that the addition of RL influence on the KSuc level, and the succinylated proteins were involved in various metabolic processes, particularly enriched in oxidative phosphorylation, tricarboxylic acid cycle (TCA) cycle, and nitrogen metabolism. Meanwhile, multiple succinylation sites on MoFe protein (NifDK) may influence nitrogenase activity. These results would provide an experimental basis for the regulation of biological nitrogen fixation with KSuc and shed new light on the mechanistic study of nitrogen fixation.

EFFECT OF WASTEWATER FROM OLIVE OIL MILLS ON NITROGENASE ACTIVITY AND GROWTH OF AZOTOBACTER CHROOCOCCUM

1993 ◽  
Vol 12 (2) ◽  
pp. 225
Author(s):  
A. García-Barrionuevo ◽  
E. Moreno ◽  
J. Quevedo-Sarmiento ◽  
J. González-López ◽  
A. Ramos-Cormenzana
Keyword(s):  
Olive Oil ◽  
Nitrogenase Activity ◽  
Azotobacter Chroococcum ◽  
Olive Oil Mills

Effect of inoculation with Azotobacter chroococcum on nitrogenase activity of Zea mays roots grown in agricultural soils under aseptic and non-sterile conditions

1988 ◽  
Vol 6 (2) ◽  
pp. 170-173 ◽  
Author(s):  
M. V. Martinez Toledo ◽  
J. Gonzalez-Lopez ◽  
T. de la Rubia ◽  
J. Moreno ◽  
A. Ramos-Cormenzana
Keyword(s):  
Zea Mays ◽  
Agricultural Soils ◽  
Nitrogenase Activity ◽  
Azotobacter Chroococcum
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