Induction of nitrate reductase and membrane cytochromes in wild type and chlorate-resistant Paracoccus denitrificans

1980 ◽  
Vol 126 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Kathleen Calder ◽  
Kathleen A. Burke ◽  
June Lascelles
Keyword(s):  
Nitrate Reductase ◽  
Paracoccus Denitrificans ◽  
Wild Type

Effects of molybdenum and tungsten on induction of nitrate reductase and formate dehydrogenase in wild type and mutant Paracoccus denitrificans

1980 ◽  
Vol 126 (2) ◽  
pp. 155-159 ◽  
Author(s):  
Kathleen A. Burke ◽  
Kathleen Calder ◽  
June Lascelles
Keyword(s):  
Nitrate Reductase ◽  
Formate Dehydrogenase ◽  
Paracoccus Denitrificans ◽  
Wild Type ◽  
And Tungsten

Molybdenum incorporation in denitrifying Azospirillum brasilense Sp7

1992 ◽  
Vol 38 (10) ◽  
pp. 1042-1047 ◽  
Author(s):  
Christian Chauret ◽  
Wilfredo L. Barraquio ◽  
Roger Knowles
Keyword(s):  
Nitrate Reductase ◽  
Key Words ◽  
Nitrate Reduction ◽  
Gel Electrophoresis ◽  
Azospirillum Brasilense ◽  
Paracoccus Denitrificans ◽  
Free Medium ◽  
Azospirillum Brasilense Sp7

Nondenaturating disc gel electrophoresis revealed that 99Mo was incorporated into the nitrate reductase of Azospirillum brasilense grown in the absence but not in the presence of tungstate. Under denitrifying conditions, A. brasilense grown in tungsten-free medium steadily accumulated 99Mo for 12 h. In contrast, Paracoccus denitrificans grown under the same conditions ceased uptake after 1 h. However, both bacteria were incapable of accumulating significant amounts of 99Mo in media containing 10 mM tungstate, even though nitrate was reduced by A. brasilense. Aerobically grown A. brasilense cells transported 99Mo more efficiently than anaerobically grown cells. Key words: Azospirillum brasilense, tungsten, molybdenum incorporation, nitrate reduction.

scholarly journals A Mutant of Paracoccus denitrificans with Disrupted Genes Coding for Cytochrome c550 and Pseudoazurin Establishes These Two Proteins as the In Vivo Electron Donors to Cytochrome cd1 Nitrite Reductase

2003 ◽  
Vol 185 (21) ◽  
pp. 6308-6315 ◽  
Author(s):  
Isobel V. Pearson ◽  
M. Dudley Page ◽  
Rob J. M. van Spanning ◽  
Stuart J. Ferguson
Keyword(s):  
Nitrite Reductase ◽  
Paracoccus Denitrificans ◽  
Wild Type ◽  
Anaerobic Conditions ◽  
Electron Mediator ◽  
Intact Cells ◽  
Cytochrome Cd1 ◽  
Membrane Bound ◽  
Electron Carriers

ABSTRACT In Paracoccus denitrificans, electrons pass from the membrane-bound cytochrome bc 1 complex to the periplasmic nitrite reductase, cytochrome cd 1. The periplasmic protein cytochrome c 550 has often been implicated in this electron transfer, but its absence, as a consequence of mutation, has previously been shown to result in almost no attenuation in the ability of the nitrite reductase to function in intact cells. Here, the hypothesis that cytochrome c 550 and pseudoazurin are alternative electron carriers from the cytochrome bc 1 complex to the nitrite reductase was tested by construction of mutants of P. denitrificans that are deficient in either pseudoazurin or both pseudoazurin and cytochrome c 550. The latter organism, but not the former (which is almost indistinguishable in this respect from the wild type), grows poorly under anaerobic conditions with nitrate as an added electron acceptor and accumulates nitrite in the medium. Growth under aerobic conditions with either succinate or methanol as the carbon source is not significantly affected in mutants lacking either pseudoazurin or cytochrome c 550 or both these proteins. We concluded that pseudoazurin and cytochrome c 550 are the alternative electron mediator proteins between the cytochrome bc 1 complex and the cytochrome cd 1-type nitrite reductase. We also concluded that expression of pseudoazurin is mainly controlled by the transcriptional activator FnrP.

Identification of an assimilatory nitrate reductase in mutants of Paracoccus denitrificans GB17 deficient in nitrate respiration

1997 ◽  
Vol 167 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Heather J. Sears ◽  
Phillip J. Little ◽  
D. J. Richardson ◽  
B. C. Berks ◽  
Stephen Spiro ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Paracoccus Denitrificans ◽  
Nitrate Respiration

A composite biochemical system for bacterial nitrate and nitrite assimilation as exemplified by Paracoccus denitrificans

2011 ◽  
Vol 435 (3) ◽  
pp. 743-753 ◽  
Author(s):  
Andrew J. Gates ◽  
Victor M. Luque-Almagro ◽  
Alan D. Goddard ◽  
Stuart J. Ferguson ◽  
M. Dolores Roldán ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Nitrogen Source ◽  
Nitrite Reductase ◽  
Paracoccus Denitrificans ◽  
Gene Clusters ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Nitrite Reduction ◽  
Anaerobic Growth ◽  
Nitrate And Nitrite

The denitrifying bacterium Paracoccus denitrificans can grow aerobically or anaerobically using nitrate or nitrite as the sole nitrogen source. The biochemical pathway responsible is expressed from a gene cluster comprising a nitrate/nitrite transporter (NasA), nitrite transporter (NasH), nitrite reductase (NasB), ferredoxin (NasG) and nitrate reductase (NasC). NasB and NasG are essential for growth with nitrate or nitrite as the nitrogen source. NADH serves as the electron donor for nitrate and nitrite reduction, but only NasB has a NADH-oxidizing domain. Nitrate and nitrite reductase activities show the same Km for NADH and can be separated by anion-exchange chromatography, but only fractions containing NasB retain the ability to oxidize NADH. This implies that NasG mediates electron flux from the NADH-oxidizing site in NasB to the sites of nitrate and nitrite reduction in NasC and NasB respectively. Delivery of extracellular nitrate to NasBGC is mediated by NasA, but both NasA and NasH contribute to nitrite uptake. The roles of NasA and NasC can be substituted during anaerobic growth by the biochemically distinct membrane-bound respiratory nitrate reductase (Nar), demonstrating functional overlap. nasG is highly conserved in nitrate/nitrite assimilation gene clusters, which is consistent with a key role for the NasG ferredoxin, as part of a phylogenetically widespread composite nitrate and nitrite reductase system.

scholarly journals The location of dissimilatory nitrite reductase and the control of dissimilatory nitrate reductase by oxygen in Paracoccus denitrificans

1980 ◽  
Vol 192 (1) ◽  
pp. 231-240 ◽  
Author(s):  
P R Alefounder ◽  
S J Ferguson
Keyword(s):  
Plasma Membrane ◽  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Paracoccus Denitrificans ◽  
Osmotic Shock ◽  
Inhibitory Effect ◽  
Nitrate Respiration ◽  
Permeability Barrier ◽  
Intact Cells ◽  
Close Relationship

1. A method is described for preparing spheroplasts from Paracoccus denitrificans that are substantially depleted of dissimilatory nitrate reductase (cytochrome cd) activity. Treatment of cells with lysozyme + EDTA together with a mild osmotic shock, followed by centrifugation, yielded a pellet of spheroplasts and a supernatant that contained d-type cytochrome. The spheroplasts were judged to have retained an intact plasma membrane on the basis that less than 1% of the activity of a cytoplasmic marker protein, malate dehydrogenase, was released from the spheroplasts. In addition to a low activity towards added nitrite, the suspension of spheroplasts accumulated the nitrite that was produced by respiratory chain-linked reduction of nitrate. It is concluded that nitrate reduction occurs at the periplasmic side of the plasma membrane irrespective of whether nitrite is generated by nitrate reduction or is added exogenously. 2. Further evidence for the integrity of the spheroplasts was that nitrate reduction was inhibited by O2, and that chlorate was reduced at a markedly lower rate than nitrate. These data are taken as evidence for an intact plasma membrane because it was shown that cells acquire the capability to reduce nitrate under aerobic conditions after addition of low amounts of Triton X-100 which, with the same titre, also overcame the permeability barrier to chlorate reduction by intact cells. The close relationship between the appearance of chlorate reduction and the loss of the inhibitory effect of O2 on nitrate reduction also suggests that the later feature of nitrate respiration is due to a control on the accessibility of nitrate to its reductase rather than on the flow of electrons to nitrate reductase.

Chlamydomonas reinhardtii nitrate reductase complex has 105 kDa subunits in the wild-type strain and a structural mutant

Plant Science ◽  
1995 ◽  
Vol 105 (2) ◽  
pp. 195-206 ◽  
Author(s):  
Kyrill L. Kalakoutskii ◽  
Emilio Fernández
Keyword(s):  
Nitrate Reductase ◽  
Chlamydomonas Reinhardtii ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
In The Wild
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