Osmotic repression of anaerobic metabolic systems in Escherichia coli

Gouesbet, Gwenola; Abaibou, Hafid; Wu, Long-Fei; Mandrand‐Berthelot, Marie‐Andrée; Blanco, Carlos

doi:10.1128/jb.175.1.214-221.1993

Cited by 14 publications

(9 citation statements)

References 52 publications

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“…[38]. Gouesbet et al [9] found that about 0.24 M KCl (osmolarity of 820 mOsm) had inhibitory and repressive effects on anaerobic enzymes and the corresponding genes in E. coli due to osmotic stress.…”

Section: Discussionmentioning

confidence: 99%

pH and base counterion affect succinate production in dual-phase Escherichia coli fermentations

Lu¹,

Eiteman²,

Altman³

2009

J Ind Microbiol Biotechnol

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Succinate production was studied in Escherichia coli AFP111, which contains mutations in pyruvate formate lyase (pfl), lactate dehydrogenase (ldhA) and the phosphotransferase system glucosephosphotransferase enzyme II (ptsG). Two-phase fermentations using a defined medium at several controlled levels of pH were conducted in which an aerobic cell growth phase was followed by an anaerobic succinate production phase using 100% (v/v) CO(2). A pH of 6.4 yielded the highest specific succinate productivity. A metabolic flux analysis at a pH of 6.4 using (13)C-labeled glucose showed that 61% of the PEP partitioned to oxaloacetate and 39% partitioned to pyruvate, while 93% of the succinate was formed via the reductive arm of the TCA cycle. The flux distribution at a pH of 6.8 was also analyzed and was not significantly different compared to that at a pH of 6.4. Ca(OH)(2) was superior to NaOH or KOH as the base for controlling the pH. By maintaining the pH at 6.4 using 25% (w/v) Ca(OH)(2), the process achieved an average succinate productivity of 1.42 g/l h with a yield of 0.61 g/g.

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Section: Discussionmentioning

confidence: 99%

pH and base counterion affect succinate production in dual-phase Escherichia coli fermentations

Lu¹,

Eiteman²,

Altman³

2009

J Ind Microbiol Biotechnol

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“…Moderate salt concentrations strongly inhibit nitrogen fixation in cyanobacteria by affecting both nitrogenase synthesis and activity (Fernandes et al 1993), and the respiratory nitrate reductase from E. coli is also inactivated by NaCl in a process which can be reversed by glycine betaine (Gouesbet et al 1993). When Rhodococcus sp.…”

Section: Figmentioning

confidence: 97%

Rhodococcus sp. RB1 grows in the presence of high nitrate and nitrite concentrations and assimilates nitrate in moderately saline environments

Blasco

Martı́nez-Luque

Madrid

et al. 2001

Archives of Microbiology

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Rhodococcus sp. RB1 was able to thrive in media with up to 0.9 M NaCl or KCl and in the presence of high concentrations of nitrate (up to 0.9 M) and nitrite (up to 60 mM), but only under oxic conditions. An adaptation period was not required for salt tolerance, but a rapid extrusion of K+ and intake of Na+ was observed after addition of 0.5 M NaCl. Nitrate assimilation was limited by the carbon supply, but nitrite was not accumulated in the culture medium, even at nitrate concentrations as high as 0.8 M, thus suggesting that nitrite reduction does not limit nitrate assimilation. The presence of NaCl or KCl did not affect nitrate or nitrite uptake, which were completely inhibited by ammonium or glutamine. Rhodococcus sp. RB1 nitrate reductase had an apparent molecular mass of 142 kDa and used NADH and reduced bromophenol blue or viologens as electron donors, independently of the presence of salt. The enzyme was associated with an NADH-diaphorase activity and was induced by nitrate and repressed by ammonium or glutamine, thus showing typical biochemical and regulatory properties of bacterial assimilatory NADH-nitrate reductases. The enzyme was active in vitro in the presence of 3 M NaCl or KCI, but the maximal activity was observed at 0.5 M salt. Addition of 2 M NaCl increased the optimal temperature of the enzyme from 12 to 32 degrees C, but the optimal pH (10.3) was unaffected.

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“…Although nitrate has been described to be an osmoprotectant in some cyanobacteria (10,28), this is obviously not the case in R. capsulatus E1F1 because of the inhibition of nitrate transport by NaCl. Respiratory nitrate reductase from Escherichia coli is also inactivated by NaCl in a process mediated by intracellular K ϩ which can be reversed by glycine betaine (11).…”

Section: Discussionmentioning

confidence: 99%

“…Salinity is one of the most important factors which can affect microbial and plant growth, and the elucidation of the molecular mechanisms involved in the adaptability to salt stress is the object of current research. Although salinity and osmotic stress have been considered similar phenomena (11,17,21,26), each has different components (10).…”

mentioning

confidence: 99%

Halotolerance of the Phototrophic Bacterium Rhodobacter capsulatus E1F1 Is Dependent on the Nitrogen Source

Igeño¹,

Moral²,

Castillo³

et al. 1995

Appl Environ Microbiol

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Phototrophic growth of the moderate halotolerant Rhodobacter capsulatus strain E1F1 in media containing up to 0.3 M NaCl was dependent on the nitrogen source used. In these media, increased growth rates and growth levels were observed in the presence of reduced nitrogen sources such as ammonium and amino acids. When the medium contained an oxidized nitrogen source (dinitrogen or nitrate), increases in salinity severely inhibited phototrophic growth. However, the addition of glycine betaine promoted halotolerance and allowed the cells to grow in 0.2 M NaCl. Inhibition of diazotrophic growth by salinity was due to a decrease in nitrogenase activity which was no longer synthesized and reversibly inactivated, both effects being alleviated by the addition of glycine betaine. In R. capsulatus E1F1, inhibition of cell growth in nitrate by salt was due to a rapid inhibition of nitrate uptake, which led to a long-term decrease in nitrate reductase activity, probably caused by repression of the enzyme. Addition of glycine betaine immediately restored nitrate uptake, but the recovery of nitrate reductase activity required several hours. Neither ammonium uptake nor ammonium assimilation through the glutamine synthetase-glutamate synthase pathway was affected by NaCl.

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Osmotic repression of anaerobic metabolic systems in Escherichia coli

Cited by 14 publications

References 52 publications

pH and base counterion affect succinate production in dual-phase Escherichia coli fermentations

pH and base counterion affect succinate production in dual-phase Escherichia coli fermentations

Rhodococcus sp. RB1 grows in the presence of high nitrate and nitrite concentrations and assimilates nitrate in moderately saline environments

Halotolerance of the Phototrophic Bacterium Rhodobacter capsulatus E1F1 Is Dependent on the Nitrogen Source

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