Cytochrome content in Azospirillum brasilense Sp 7 grown under aerobic and denitrifying conditions

1987 ◽  
Vol 33 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Roger Lalande ◽  
Roger Knowles
Keyword(s):  
Electron Acceptor ◽  
Azospirillum Brasilense ◽  
Nitrate Reductase Activity ◽  
Soluble Fraction ◽  
Reductase Activity ◽  
Batch Cultures ◽  
Final Electron ◽  
Cytochrome Content ◽  
Soluble C ◽  
Final Electron Acceptor

Azospirillum brasilense Sp 7 was grown in batch cultures with O2, [Formula: see text], [Formula: see text], or N2O as final electron acceptor. There were marked differences in cytochrome composition depending on the O2 status of the culture and the electron acceptor utilized. Highly aerated cultures showed no [Formula: see text] reduction and the cytochrome composition (a soluble c-type and particulate aa3, b, and c cytochromes) was not affected by the presence of[Formula: see text]. Under low aeration, in the presence of [Formula: see text], nitrate reductase activity occurred and there was a significant increase in the soluble and particulate cytochromes. Particulate cytochrome b-556 was observed only under high aeration and the cytochrome aa3, observed under both high and low aeration, decreased as the O2 concentration decreased. A particulate CO-binding cytochrome of type o was observed in the cells grown under high aeration. Cytochrome cd nitrite reductase was observed only in the soluble fraction of [Formula: see text]-grown cultures, which also contained the highest concentrations of the soluble cytochrome c-548 and the particulate c-551. N2O-grown cultures showed b-560 and c-551 cytochromes in the particulate and the c-548 cytochrome in the soluble fraction.

scholarly journals Superoxide dismutase, catalase, and peroxidase in ammonium-grown and nitrogen-fixing Azospirillum brasilense

1984 ◽  
Vol 30 (10) ◽  
pp. 1222-1228 ◽  
Author(s):  
Richard W. Clara ◽  
Roger Knowles
Keyword(s):  
Superoxide Dismutase ◽  
Electron Acceptor ◽  
Azospirillum Brasilense ◽  
Polyacrylamide Gel Electrophoresis ◽  
Growth Conditions ◽  
Sod Activity ◽  
Batch Cultures ◽  
Physiological Conditions ◽  
Azospirillum Brasilense Sp7 ◽  
In Cells

Superoxide dismutase (SOD), catalase (CAT), and peroxidase (PER) activities were studied in ammonium-grown and N2-fixing batch cultures of Azospirillum brasilense Sp7. PER activity, as measured using o-dianisidine or 3,3′-diaminobenzidine as the H donor, was not significant in most growth conditions. SOD activity increased in response to higher O2 concentrations but was also present in cells grown anaerobically with nitrate [Formula: see text] or nitrous oxide (N2O) as electron acceptor. CAT activity increased at lower O2 concentrations and was highest in cells grown anaerobically with [Formula: see text] as electron acceptor. Polyacrylamide gel electrophoresis of cell-free extracts revealed only one band of SOD activity under each of the physiological conditions employed, compared with three for aerobically grown Escherichia coli K12. This band proved to be iron-containing SOD (FeSOD) on the basis of inhibitor sensitivity.

scholarly journals Respiratory Nitrate Ammonification by Shewanella oneidensis MR-1

2006 ◽  
Vol 189 (2) ◽  
pp. 656-662 ◽  
Author(s):  
Claribel Cruz-García ◽  
Alison E. Murray ◽  
Joel A. Klappenbach ◽  
Valley Stewart ◽  
James M. Tiedje
Keyword(s):  
Nitrous Oxide ◽  
Nitrate Reductase ◽  
Electron Acceptor ◽  
Nitrate Reduction ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Shewanella Oneidensis ◽  
Gene Encoding ◽  
Nitrate Ammonification ◽  
Sequential Reduction

ABSTRACT Anaerobic cultures of Shewanella oneidensis MR-1 grown with nitrate as the sole electron acceptor exhibited sequential reduction of nitrate to nitrite and then to ammonium. Little dinitrogen and nitrous oxide were detected, and no growth occurred on nitrous oxide. A mutant with the napA gene encoding periplasmic nitrate reductase deleted could not respire or assimilate nitrate and did not express nitrate reductase activity, confirming that the NapA enzyme is the sole nitrate reductase. Hence, S. oneidensis MR-1 conducts respiratory nitrate ammonification, also termed dissimilatory nitrate reduction to ammonium, but not respiratory denitrification.

Anaerobic biodegradation of BTEX using Mn(IV) and Fe(III) as alternative electron acceptors

2003 ◽  
Vol 48 (6) ◽  
pp. 125-131 ◽  
Author(s):  
W.R. Villatoro-Monzón ◽  
A.M. Mesta-Howard ◽  
E. Razo-Flores
Keyword(s):  
Manganese Oxide ◽  
Electron Acceptor ◽  
Anaerobic Biodegradation ◽  
Electron Acceptors ◽  
Batch Experiments ◽  
First Report ◽  
Reducing Conditions ◽  
Final Electron ◽  
Amorphous Manganese Oxide ◽  
Final Electron Acceptor

Anaerobic BTEX biodegradation was tested in batch experiments using an anaerobic sediment as inoculum under Fe(III) and Mn(IV) reducing conditions. All BTEX were degraded under the conditions tested, specially under Mn(IV) reducing conditions, where benzene was degraded at a rate of 0.8 μmol l-1d-1, significantly much faster than Fe(III) reducing conditions. Under Fe(III) reducing conditions, ethylbenzene was the compound that degraded at the faster rate of 0.19 μmol l-1d-1. Mn(IV) reducing conditions are energetically more favourable than Fe(III), therefore, BTEX were more rapidly degraded under Mn(IV) reducing conditions. These results represent the first report of the degradation of benzene with Mn(IV) as the final electron acceptor. Amorphous manganese oxide is a natural widely distributed metal in groundwater, where it can be microbiologically reduced, leading to the degradation of monoaromatic compounds.

scholarly journals Anaerobic α-Amylase Production and Secretion with Fumarate as the Final Electron Acceptor in Saccharomyces cerevisiae

2013 ◽  
Vol 79 (9) ◽  
pp. 2962-2967 ◽  
Author(s):  
Zihe Liu ◽  
Tobias Österlund ◽  
Jin Hou ◽  
Dina Petranovic ◽  
Jens Nielsen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Folding ◽  
Protein Secretion ◽  
Electron Acceptor ◽  
Anaerobic Growth ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Content Type ◽  
Final Electron ◽  
Final Electron Acceptor

ABSTRACTIn this study, we focus on production of heterologous α-amylase in the yeastSaccharomyces cerevisiaeunder anaerobic conditions. We compare the metabolic fluxes and transcriptional regulation under aerobic and anaerobic conditions, with the objective of identifying the final electron acceptor for protein folding under anaerobic conditions. We find that yeast produces more amylase under anaerobic conditions than under aerobic conditions, and we propose a model for electron transfer under anaerobic conditions. According to our model, during protein folding the electrons from the endoplasmic reticulum are transferred to fumarate as the final electron acceptor. This model is supported by findings that the addition of fumarate under anaerobic (but not aerobic) conditions improves cell growth, specifically in the α-amylase-producing strain, in which it is not used as a carbon source. Our results provide a model for the molecular mechanism of anaerobic protein secretion using fumarate as the final electron acceptor, which may allow for further engineering of yeast for improved protein secretion under anaerobic growth conditions.

A novel oxidizer-less and high performance microbial fuel cell by using DNA as a final electron acceptor in the cathodic chamber

2016 ◽  
Vol 41 (31) ◽  
pp. 13611-13618 ◽  
Author(s):  
Maryam Asghary ◽  
Jahan Bakhsh Raoof ◽  
Mostafa Rahimnejad ◽  
Reza Ojani
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Electron Acceptor ◽  
High Performance ◽  
Final Electron ◽  
Cathodic Chamber ◽  
Final Electron Acceptor

scholarly journals Application methods of Azospirillum brasilense in first- and second-crop corn

2019 ◽  
Vol 23 (11) ◽  
pp. 840-846
Author(s):  
Rita de C. F. Alvarez ◽  
Jamile Benetão ◽  
Gustavo R. Barzotto ◽  
Maria G. de O. Andrade ◽  
Sebastião F. de Lima
Keyword(s):  
Nitrate Reductase ◽  
Azospirillum Brasilense ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Fertilizer Application ◽  
Early Maturity ◽  
N Concentration ◽  
Chlorophyll Index ◽  
Crop Harvest ◽  
Corn Plants

ABSTRACT This study investigated whether inoculation of Azospirillum brasilense in the seeds or sowing furrow could reduce the need for nitrogen fertilizer application in the corn grown in the first and second crop harvest. The experiments were conducted, in the municipality of Chapadão do Sul, MS, Brazil, in the first crop harvest (2014/2015) and in the second crop harvest (2016). The early maturity hybrids CD 384 HX and P3132H were used in the first and in the second harvest corn, respectively. In both experiments, the experimental design was the randomized blocks with eight treatments and three repetitions. At the silking (R1 stage), the leaf N concentration, relative chlorophyll index and nitrate reductase activity were measured, at the physiological maturity (R6 stage), the plant height, first ear insertion height, one hundred grain mass, grain yield and grain N concentration were measured. In the first crop harvest, the application of Azospirillum brasilense at the sowing furrow resulted in higher N concentration and relative chlorophyll index in corn leaves, while the inoculation of A. brasilense in the seeds provided higher N concentration in the grains. The nitrate reductase activity in corn leaves was lower when inoculation was performed. In the second crop harvest, the inoculation did not affected the N concentration in the leaves and in the grains, the relative chlorophyll index and the growth of corn plants. Inoculation in the sowing furrow associated with the application of 20 kg N ha-1 at sowing and 120 kg N ha-1 at topdressing resulted in lower nitrate reductase activity.

scholarly journals Effect of tungsten on nitrate and nitrite reductases in Azospirillum brasilense Sp7

1991 ◽  
Vol 37 (10) ◽  
pp. 744-750 ◽  
Author(s):  
Christian Chauret ◽  
Roger Knowles
Keyword(s):  
Nitrate Reductase ◽  
Nitrite Reductase ◽  
Azospirillum Brasilense ◽  
Nitrate Reductase Activity ◽  
Paracoccus Denitrificans ◽  
Reductase Activity ◽  
Whole Cells ◽  
Azospirillum Brasilense Sp7 ◽  
Nitrite Reductase Activity ◽  
Nitrate And Nitrite

Tungstate, at concentrations that completely suppressed nitrate reductase activity in Paracoccus denitrificans, caused only partial inhibition of nitrate reductase in Azospirillum brasilense Sp7. Nitrate reductase activity in cell-free extracts was much more sensitive than whole cells to tungstate, suggesting that there may be a barrier to its transport. Nitrite reductase activity was partially inhibited by tungstate in both whole cells and cell-free extracts. Azospirillum brasilense apparently scavenged enough contaminating molybdenum from molybdenum-limited medium to allow maximum nitrate reductase activity, which was not stimulated by added molybdate. Cells grown in molybdenum-depleted medium could not reduce nitrate. Nitrate concentrations less than 0.25 mM inhibited activity, but not synthesis, of nitrite reductase and caused significant accumulation of nitrite during reduction of nitrate. Key words: Azospirillum brasilense, Paracoccus denitrificans, nitrate reductase, nitrite reductase, tungsten, molybdenum, denitrification.

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