Nitrate reductase of Escherichia coli: Completion of the nucleotide sequence of the nar operon and reassessment of the role of the α and β subunits in iron binding and electron transfer

1989 ◽  
Vol 218 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Francis Blasco ◽  
Chantal Iobbi ◽  
Gerard Giordano ◽  
Marc Chippaux ◽  
Violaine Bonnefoy
Keyword(s):  
Escherichia Coli ◽  
Electron Transfer ◽  
Nucleotide Sequence ◽  
Nitrate Reductase ◽  
Iron Binding ◽  
Α And Β Subunits

scholarly journals Distribution of Lactoferrin Is Related with Dynamics of Neutrophils in Bacterial Infected Mice Intestine

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1496 ◽  
Author(s):  
Li Liang ◽  
Zhen-Jie Wang ◽  
Guang Ye ◽  
Xue-You Tang ◽  
Yuan-Yuan Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Mucosal Immunity ◽  
Mrna Levels ◽  
Iron Binding ◽  
E Coli ◽  
New Knowledge ◽  
Activated Neutrophils ◽  
Binding Glycoprotein

Lactoferrin (Lf) is a conserved iron-binding glycoprotein with antimicrobial activity, which is present in secretions that recover mucosal sites regarded as portals of invaded pathogens. Although numerous studies have focused on exogenous Lf, little is known about its expression of endogenous Lf upon bacterial infection. In this study, we investigated the distribution of Lf in mice intestine during Escherichia coli (E. coli) K88 infection. PCR and immunohistology staining showed that mRNA levels of Lf significantly increased in duodenum, ileum and colon, but extremely decreased in jejunum at 8 h and 24 h after infection. Meanwhile, endogenous Lf was mostly located in the lamina propria of intestine villi, while Lf receptor (LfR) was in the crypts. It suggested that endogenous Lf-LfR interaction might not be implicated in the antibacterial process. In addition, it was interesting to find that the infiltration of neutrophils into intestine tissues was changed similarly to Lf expression. It indicated that the variations of Lf expression were rather due to an equilibrium between the recruitment of neutrophils and degranulation of activated neutrophils. Thus, this new knowledge will pave the way to a more effective understanding of the role of Lf in intestinal mucosal immunity.

scholarly journals From Rust to Quantum Biology: The Role of Iron in Retina Physiopathology

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 705 ◽  
Author(s):  
Emilie Picard ◽  
Alejandra Daruich ◽  
Jenny Youale ◽  
Yves Courtois ◽  
Francine Behar-Cohen
Keyword(s):  
Electron Transfer ◽  
Iron Homeostasis ◽  
Iron Chelation ◽  
Retinal Diseases ◽  
Iron Binding ◽  
Vital Functions ◽  
Iron Binding Protein ◽  
And Function ◽  
Organ Dysfunctions

Iron is essential for cell survival and function. It is a transition metal, that could change its oxidation state from Fe2+ to Fe3+ involving an electron transfer, the key of vital functions but also organ dysfunctions. The goal of this review is to illustrate the primordial role of iron and local iron homeostasis in retinal physiology and vision, as well as the pathological consequences of iron excess in animal models of retinal degeneration and in human retinal diseases. We summarize evidence of the potential therapeutic effect of iron chelation in retinal diseases and especially the interest of transferrin, a ubiquitous endogenous iron-binding protein, having the ability to treat or delay degenerative retinal diseases.

A Study on the Etiological Factors of Bilharzial Bladder Cancer in Egypt. 6. The Possible Role of Urinary Bacteria

1982 ◽  
Vol 68 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Abdelbaset Anwer El-Aaser ◽  
Mahmoud Mohamed El-Merzabani ◽  
Nadia Ahmed Higgy ◽  
Abdel E. El-Habet
Keyword(s):  
Escherichia Coli ◽  
Bladder Cancer ◽  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Bacterial Infection ◽  
Schistosoma Haematobium ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Glucuronidase Activity

A correlation was obtained between a positive nitrite test in urine and the severity of urinary bacterial infection. Bacteria isolated from the urine of bilharzial or bladder cancer patients were found to be rich in nitrate reductase activity. « Escherichia coli » was the most common microorganism isolated from these specimens. Urine and several urinary constituents activate bacterial nitrate reductase. β-Glucuronidase activity in the urine of patients with chronic « Schistosoma haematobium » infection and bladder cancer was measured and shown to be significantly greater than that of urine of normal control subjects. Urinary bacterial infection was shown to be the source of the increased urinary level of enzyme activity at pH 7.0.

scholarly journals Competition between Escherichia coli strains expressing either a periplasmic or a membrane-bound nitrate reductase: does Nap confer a selective advantage during nitrate-limited growth?

1999 ◽  
Vol 344 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Laura C. POTTER ◽  
Paul MILLINGTON ◽  
Lesley GRIFFITHS ◽  
Gavin H. THOMAS ◽  
Jeffrey A. COLE
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Nitrate Reductase ◽  
Electron Acceptor ◽  
Physiological Role ◽  
Selective Advantage ◽  
Limited Growth ◽  
Terminal Electron Acceptor ◽  
Periplasmic Nitrate Reductase

The physiological role of the periplasmic nitrate reductase, Nap, one of the three nitrate reductases synthesized by Escherichia coli K-12, has been investigated. A series of double mutants that express only one nitrate reductase were grown anaerobically in batch cultures with glycerol as the non-fermentable carbon source and nitrate as the terminal electron acceptor. Only the strain expressing nitrate reductase A grew rapidly under these conditions. Introduction of a narL mutation severely decreased the growth rate of the nitrate reductase A strain, but enhanced the growth of the Nap+ strain. The ability to use nitrate as a terminal electron acceptor for anaerobic growth is therefore regulated primarily by the NarL protein at the level of transcription. Furthermore, the strain expressing nitrate reductase A had a substantial selective advantage in competition with the strain expressing only Nap during nitrate-sufficient continuous culture. However, the strain expressing Nap was preferentially selected during nitrate-limited continuous growth. The saturation constants for nitrate for the two strains (which numerically are equal to the nitrate concentrations at half of the maximum specific growth rate and therefore reflect the relative affinities for nitrate) were estimated using the integrated Monod equation to be 15 and 50 μM for Nap and nitrate reductase A respectively. This difference is sufficient to explain the selective advantage of the Nap+ strain during nitrate-limited growth. It is concluded that one physiological role of the periplasmic nitrate reductase of enteric bacteria is to enable bacteria to scavenge nitrate in nitrate-limited environments.

scholarly journals NapGH components of the periplasmic nitrate reductase of Escherichia coli K-12: location, topology and physiological roles in quinol oxidation and redox balancing

2004 ◽  
Vol 379 (1) ◽  
pp. 47-55 ◽  
Author(s):  
T. Harma C. BRONDIJK ◽  
Arjaree NILAVONGSE ◽  
Nina FILENKO ◽  
David J. RICHARDSON ◽  
Jeffrey A. COLE
Keyword(s):  
Escherichia Coli ◽  
Electron Transfer ◽  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Residual Rate ◽  
Periplasmic Nitrate Reductase ◽  
Essential Components ◽  
K 12

Nap (periplasmic nitrate reductase) operons of many bacteria include four common, essential components, napD, napA, napB and napC (or a homologue of napC). In Escherichia coli there are three additional genes, napF, napG and napH, none of which are essential for Nap activity. We now show that deletion of either napG or napH almost abolished Nap-dependent nitrate reduction by strains defective in naphthoquinone synthesis. The residual rate of nitrate reduction (approx. 1% of that of napG+H+ strains) is sufficient to replace fumarate reduction in a redox-balancing role during growth by glucose fermentation. Western blotting combined with β-galactosidase and alkaline phosphatase fusion experiments established that NapH is an integral membrane protein with four transmembrane helices. Both the N- and C-termini as well as the two non-haem iron–sulphur centres are located in the cytoplasm. An N-terminal twin arginine motif was shown to be essential for NapG function, consistent with the expectation that NapG is secreted into the periplasm by the twin arginine translocation pathway. A bacterial two-hybrid system was used to show that NapH interacts, presumably on the cytoplasmic side of, or within, the membrane, with NapC. As expected for a periplasmic protein, no NapG interactions with NapC or NapH were detected in the cytoplasm. An in vitro quinol dehydrogenase assay was developed to show that both NapG and NapH are essential for rapid electron transfer from menadiol to the terminal NapAB complex. These new in vivo and in vitro results establish that NapG and NapH form a quinol dehydrogenase that couples electron transfer from the high midpoint redox potential ubiquinone–ubiquinol couple via NapC and NapB to NapA.

A New Paradigm for Electron Transfer through Escherichia coli Nitrate Reductase A

Biochemistry ◽  
2014 ◽  
Vol 53 (28) ◽  
pp. 4549-4556 ◽  
Author(s):  
Justin G. Fedor ◽  
Richard A. Rothery ◽  
Joel H. Weiner
Keyword(s):  
Escherichia Coli ◽  
Electron Transfer ◽  
Nitrate Reductase ◽  
New Paradigm
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