Nitrates Escherichia coli

Fig. 6. Representative EPR spectra displayed by trinuclear and tetranucleEir iron-sulfur centers, (a) and (b) [3Fe-4S] + center in the NarH subunit of Escherichia coli nitrate reductase and the Ni-Fe hydrogenase fromD. gigas, respectively, (c) [4Fe-4S] + center in D. desulfuricans Norway ferredoxin I. (d) [4Fe-4S] center in Thiobacillus ferrooxidans ferredoxin. Experimental conditions temperature, 15 K microwave frequency, 9.330 GHz microwave power, (a) 100 mW, (b) 0.04 mW, (c) smd (d) 0.5 mW modulation amplitude (a), (c), (d) 0.5 mT, (b) 0.1 mT.

A strain of Escherichia coli produces a naphthotriazole from 2,3-diaminonaphthalene and nitrite that is formed from nitrate by the action of nitrate reductase. The initial product is NO, which is converted by reactions with oxygen into the active nitrosylating agent that reacts chemically with the amine (Ji and Hollocher 1988). A comparable reaction may plausibly account for the formation of dimethylnitrosamine by Pseudomonas stutzeri during growth with dimethylamine in the presence of nitrite (Mills and Alexander 1976) (Figure 2.2f). 

The conditions under which these function and their regulation depend on the organism. For example, in Escherichia coli, oxygen represses the synthesis of the other reductases, and under anaerobic conditions the reductases for fumarate, DMSO, and TMAO are repressed by nitrate. This does not apply to Wolinella succinogenes in which sulfur represses the synthesis of the more positive electron acceptors nitrate and fumarate (Lorenzen et al. 1993). The DMSO reductase from Escherichia coli (Weiner et al. 1988) has a broad substrate versatility, and is able to reduce a range of sulfoxides and A-oxides. Anaerobic sulfate reduction is not discussed here in detail. 

Avazeri C, R Turner, J Pommier, J Weiner, GG Giordano, A Vermeglio (1997) Tellurite resistance activity of nitrate reductase is responsible for the basal resistance of Escherichia coli to tellurite. Microbiology (UK) 143 1181-1189. 

Nitrate reductase ) Escherichia coli Reduced methyl viologen NO3 ... 

Cambella and Antia [385] determined phosphonates in seawater by fractionation of the total phosphorus. The seawater sample was divided into two aliquots. The first was analysed for total phosphorus by the nitrate oxidation method capable of breaking down phosphonates, phosphate esters, nucleotides, and polyphosphates. The second aliquot was added to a suspension of bacterial (Escherichia coli) alkaline phosphatase enzyme, incubated for 2h at 37 °C and subjected to hot acid hydrolysis for 1 h. The resultant hot acid-enzyme sample was assayed for molybdate reactive phosphate which was estimated as the sum of enzyme hydrolysable phosphate and acid hydrolysable... 

The nitrate (NOp content in crops is one of the most important indicators of farm production quality. Nitrate content in food is strictly regulated because of its toxicity, especially in young children. The actual toxin is not the nitrate ion itself but rather the nitrite ion (NOp, which is formed when nitrate is reduced by intestinal bacteria, notably Escherichia coli. In adults, nitrate is absorbed high in the digestive tract before reduction can take place. In infants, whose stomachs are less acidic, E. coli can colonize higher up the digestive tract and therefore reduce the NOJ to NCp before it is absorbed. 

Escherichia coli [NiFe] hydrogenase 3 Membrane-associated component of the formate hydrogen lyase complex H2 production during fermentation H2 uptake under anaerobic conditions Anaerobiosis, carbon source limitation, phosphate limitation, molybdenum, nitrate, formate 7.8... 

Richard, D. J., Sawers, G., Sargent, E, McWalter, L. and Boxer, D. H. (1999) Transcriptional regulation in response to oxygen and nitrate of the operons encoding the [NiFe] hydro-genases 1 and 2 oi Escherichia coli. Microbiology, 145, 2903-12. 

Berg BL, Li J, Heider J, Stewart V. 1991. Nitrate-inducible formate dehydrogenase in Escherichia coli K12. J. Biol Chem 266 22380-5. 

Bacterial electrodes [11, 31, 33, 46, 48, 49, 60] In this type of electrode, a suspension of suitable bacteria is placed between the sensor proper and a dialysis membrane that prevents passage of high-molecular substances (see fig. 8.3). The sensor is usually a gas probe. In the simple types of bacterial electrode, the determinand is converted by a suitable strain of bacteria into a product sensed by the gas probe. Thus it is possible to determine arginine [46], glutamine [48],/.-aspartic acid [31],/.-histidine [60] and nitrate [33]. Hybrid bacterial - enzyme electrodes contain both a bacterial strain and a suitable enzyme. For example, an extract from ivingas Neurospora chossa can be used as a source of NAD nucleosidase and an Escherichia coli culture as a source of nicotinamide deaminase, so that the electrode responds to NAD [49] as a result of the series of reactions... 

Several excellent review articles have addressed this issue from molecular biology to high density cell cultures of Escherichia coli cells [1-4]. We will briefly review E. coli promoter system with emphasis on oxygen-dependent VHb and nar promoters and discuss fed-batch cultures of the nar promoter system requiring nitrates or no nitrates. These new systems will be compared with other existing promoter systems. 

Stuehr, D. j., and Marietta, M. A. (1985). Mammalian nitrate biosynthesis Mouse macrophages produce nitrite and nitrate in response to Escherichia coli lipopolysaccharide. Proc. Natl. Acad. Sci. U.S.A. 82, 7738-7742. 

Wagner, D., and Tannenbaum, S. R. (1982). Enhancement of nitrate biosynthesis by Escherichia coli lipopolysaccharide. In Nitrosamines and Human Cancer (P. N. Magee, ed.). Cold Spring Harbor Laboratory, Cold Spring Harbor, New York. 

Ji, X.-B, and Hollocher, T. C. (1989). Nitrate reductase of Escherichia coli as a NO-pro-ducing nitrite reductase. Biochem. Arch. 5, 61-66. 

Noji, S. Nohno, T. Saito, T. Taniguchi, S. The narK gene product participates in nitrate transport induced in Escherichia coli nitrate-respiring cells. FEBS Lett., 252, 139-143 (1989)... 

Rabin, R.S. Stewart, V. Either of two functionally redundant sensor proteins, NarX and NarQ, is sufficient for nitrate regulation in Escherichia coli K-12. Proc. Natl. Acad. Sci. USA, 89, 8419-8423 (1992)... 

Nitrate reductase (dissimilatory) Escherichia coli 200000 1 4Fe4S4... 

As noted in Section 62.1.9.6, reduction of nitrate may occur by assimilatory or dissimilatory pathways. In the former case, the nitrate produced is reduced further to ammonia, which is incorporated into the cell. In the latter case, nitrate is reduced anaerobically to nitrite, serving as an electron acceptor in the respiration of facultative or a few obligate anaerobic bacteria. The example of Escherichia coli has been considered in Section 62.1.13.4.3. This process is usually terminated at nitrite, which accumulates around the cells, but may proceed further1511 as nitrite-linked respiration in the process of denitrification. 

Hyde, G.E. Campbell, W.H. (1990). High-level expression in Escherichia coli of the catalytically active flavin domain of corn leaf NADH-nitrate, reductase and its comparison to human NADH-cytochrome b5 reductase. Biochemical and Biophysical Research Communications 168, 1285-91. 

Figure 7 The modus operandi of nitrate reductase (a) assimilatory nitrate reductase (plants, fungi, algae) (b) respiratory (dissimilatory) nitrate reductase (.Escherichia coli, Pseudomonas).

IV.C.3. The Molybdenum Site of Respiratory Nitrate Reductase (Escherichia coli)... 

Relatively recently Fe/S proteins have been found to function in the regulation of biosynthesis. This can be by promoting deoxyribonucleic acid (DNA) transcription, e.g. the [2Fe-2S] containing Escherichia coli superoxide-activated (SoxR) transcription activator [10-12], or the presumably [4Fe-4S]-containing E. coli transcription factor fumarate nitrate reduction (FNR) [13,14], Alternatively, the Fe/S protein can act by interference with messenger ribonucleic acid (mRNA) translation, i.e., the iron regulatory proteins (IRPs) [15,16], These interactions are stoichiometric, therefore not catalytic. Presumably, they are also a form of sensoring, namely, of oxidants and/or iron [17],... 

Kapralek, F., Jechova, E., and Otavova, M. (1982) Two sites of oxygen control in induced synthesis of respiratory nitrate reductase in Escherichia coli. J. Bacteriol. 149, 1142-1145. 

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