Basal ppGpp level adjustment shown by new spoT mutants affect steady state growth rates and rrnA ribosomal promoter regulation in Escherichia coli

1988 ◽  
Vol 213 (2-3) ◽  
pp. 214-222 ◽  
Author(s):  
Edoardo Sarubbi ◽  
Kenneth E. Rudd ◽  
Michael Cashel
Keyword(s):  
Escherichia Coli ◽  
Steady State ◽  
Growth Rates ◽  
Promoter Regulation ◽  
Steady State Growth ◽  
State Growth

scholarly journals Gene activities for ribosomal components in Escherichia coli B/r

1975 ◽  
Vol 150 (3) ◽  
pp. 469-475 ◽  
Author(s):  
H Bremer ◽  
P P Dennis
Keyword(s):  
Escherichia Coli ◽  
Steady State ◽  
Ribosomal Rna ◽  
Growth Rates ◽  
Ribosomal Proteins ◽  
Rrna Genes ◽  
Steady State Growth ◽  
State Growth ◽  
Escherichia Coli B

The relative transcriptional activities of genes coding for ribosomal RNA (rRNA) and ribosomal proteins (r-proteins) at a steady-state growth rates ranging from 0.65 to 2.1 doublings/h can be estimated from previous measurements of the synthesis rates of stable and unstable RNA (Pato & von Meyenburg, 1970; Nierlich, 1972a,b; Bremer et al., 1973; Dennis & Bremer, 1973b, 1974b) and ribosomal proteins (Schleif, 1967; Dennis & Bremer, 1974a). Comparison of these transcriptional activities suggests that the expression of the r-protein genes and rRNA genes is controlled seperately.

scholarly journals Estimates of the steady state growth rates for some European countries

2012 ◽  
Vol 29 (4) ◽  
pp. 1119-1125 ◽  
Author(s):  
Paolo Casadio ◽  
Antonio Paradiso ◽  
B. Bhaskara Rao
Keyword(s):  
Steady State ◽  
Growth Rates ◽  
European Countries ◽  
Steady State Growth ◽  
State Growth

scholarly journals Post-translational control of PlsB is sufficient to coordinate membrane synthesis with growth in Escherichia coli

2019 ◽  
Author(s):  
Marek J Noga ◽  
Ferhat Büke ◽  
Niels JF van den Broek ◽  
Nicole Imholz ◽  
Nicole Scherer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Steady State ◽  
Fatty Acid ◽  
State Regulation ◽  
Phospholipid Synthesis ◽  
Membrane Synthesis ◽  
Allosteric Control ◽  
Steady State Growth ◽  
State Growth ◽  
Single Enzyme

AbstractEvery cell must produce enough membrane to contain itself. However, the mechanisms by which the rate of membrane synthesis is coupled with the rate of cell growth remain unresolved. By comparing substrate and enzyme concentrations of the fatty acid and phospholipid synthesis pathways of Escherichia coli across a 3-fold range of carbon-limited growth rates, we show that the rate of membrane phospholipid synthesis during steady-state growth is determined principally through allosteric control of a single enzyme, PlsB. Due to feedback regulation of the fatty acid pathway, PlsB activity also indirectly controls synthesis of lipopolysaccharide, a major component of the outer membrane synthesized from a fatty acid synthesis intermediate. Surprisingly, concentrations of the enzyme that catalyses the committed step of lipopolysaccharide synthesis (LpxC) do not vary across steady-state growth conditions, suggesting that steady-state lipopolysaccharide synthesis is modulated primarily via indirect control by PlsB. In contrast to steady-state regulation, we find that responses to environmental perturbations are triggered directly via changes in acetyl-CoA concentrations, which enables rapid adaptation. Adaptations are further modulated by ppGpp, which regulates PlsB activity during slow growth and growth arrest. The strong reliance of the membrane synthesis pathway upon post-translational regulation ensures both reliability and responsiveness of membrane synthesis.SignificanceHow do bacteria cells grow without breaking their membranes? Although the biochemistry of fatty acid and membrane synthesis is well-known, how membrane synthesis is balanced with growth and metabolism has remained unclear. This is partly due to the many control points that have been discovered within the membrane synthesis pathways. By precisely establishing the contributions of individual pathway enzymes, our results simplify the model of membrane biogenesis in the model bacteria species Escherichia coli. Specifically, we find that allosteric control of a single enzyme, PlsB, is sufficient to balance growth with membrane synthesis and to ensure that growing E. coli produces sufficient membrane. Identifying the signals that activate and deactivate PlsB will answer the question of how membrane synthesis is synchronized with growth.

scholarly journals Posttranslational Control of PlsB Is Sufficient To Coordinate Membrane Synthesis with Growth in Escherichia coli

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Marek J. Noga ◽  
Ferhat Büke ◽  
Niels J. F. van den Broek ◽  
Nicole C. E. Imholz ◽  
Nicole Scherer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Steady State ◽  
Fatty Acid ◽  
Phospholipid Synthesis ◽  
Membrane Synthesis ◽  
Content Type ◽  
Allosteric Control ◽  
Steady State Growth ◽  
State Growth ◽  
Single Enzyme

ABSTRACT Every cell must produce enough membrane to contain itself. However, the mechanisms by which the rate of membrane synthesis is coupled with the rate of cell growth remain unresolved. By comparing substrate and enzyme concentrations of the fatty acid and phospholipid synthesis pathways of Escherichia coli across a 3-fold range of carbon-limited growth rates, we show that the rate of membrane phospholipid synthesis during steady-state growth is determined principally through allosteric control of a single enzyme, PlsB. Due to feedback regulation of the fatty acid pathway, PlsB activity also indirectly controls synthesis of lipopolysaccharide, a major component of the outer membrane synthesized from a fatty acid synthesis intermediate. Surprisingly, concentrations of the enzyme that catalyzes the committed step of lipopolysaccharide synthesis (LpxC) do not differ across steady-state growth conditions, suggesting that steady-state lipopolysaccharide synthesis is modulated primarily via indirect control by PlsB. In contrast to steady-state regulation, we found that responses to environmental perturbations are triggered directly via changes in acetyl coenzyme A (acetyl-CoA) concentrations, which enable rapid adaptation. Adaptations are further modulated by ppGpp, which regulates PlsB activity during slow growth and growth arrest. The strong reliance of the membrane synthesis pathway upon posttranslational regulation ensures both the reliability and the responsiveness of membrane synthesis. IMPORTANCE How do bacterial cells grow without breaking their membranes? Although the biochemistry of fatty acid and membrane synthesis is well known, how membrane synthesis is balanced with growth and metabolism has remained unclear. This is partly due to the many control points that have been discovered within the membrane synthesis pathways. By precisely establishing the contributions of individual pathway enzymes, our results simplify the model of membrane biogenesis in the model bacterial species Escherichia coli. Specifically, we found that allosteric control of a single enzyme, PlsB, is sufficient to balance growth with membrane synthesis and to ensure that growing E. coli cells produce sufficient membrane. Identifying the signals that activate and deactivate PlsB will resolve the issue of how membrane synthesis is synchronized with growth.

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