scholarly journals Polypeptide-chain-elongation rate in Escherichia coli B/r as a function of growth rate

1976 ◽  
Vol 160 (2) ◽  
pp. 185-194 ◽  
Author(s):  
R Young ◽  
H Bremer
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Growth Rate ◽  
Growth Rates ◽  
Elongation Rate ◽  
Peptide Chain ◽  
Chain Elongation ◽  
Slow Growing ◽  
Kinetics Of ◽  
Escherichia Coli B

By evaluating the kinetics of radioactive labelling of nascent and finished polypeptides, the peptide-chain elongation rate for Escherichia coli B/r at three different growth rates (mu) was determined to be 17 amino acids/s for the fast-growing cells (mu equals 1.3 and 2.0 doublings/h) and 12 amino acids/s for slow-growing cells (mu equals 0.67 doublings/h). The results agree with the growth-rate-dependence of the rate of peptide-chain elongation found for the translation of newly induced β-galactosidase messenger in this strain and under these conditions of growth [Dalbow & Young (1975) Biochem. J. 150, 13-20]. Together with the previously observed ribosome efficiency at these growth rates [Dennis & Bremer (1974) J. Mol. Biol. 84, 407-422] the results indicate that the fraction of ribosomes engaged in protein synthesis is about 0.8 at all three growth rates.

scholarly journals Synthesis time of β-galactosidase in Escherichia coli B/r as a function of growth rate

1975 ◽  
Vol 150 (1) ◽  
pp. 13-20 ◽  
Author(s):  
D G Dalbow ◽  
R Young
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Growth Rate ◽  
Peptide Chain ◽  
Chain Elongation ◽  
Chain Growth ◽  
Synthesis Time ◽  
Fast Growing ◽  
Kinetics Of ◽  
Escherichia Coli B

By analysing the kinetics of β-galactosidase accumulation after induction, the synthesis time of β-galactosidase in Escherichia coli B/r was found to be 75s in rapidly growing cells (1.36 and 2.1 doublings/h), and 90s in slowly growing cells (0.63 doubling/h). These values correspond to peptide-chain-elongation rates of 16 and 13 amino acids/s respectively, in agreement with previous findings, indicating that the peptide-chain growth rate is constant (presumably maximal) in fast-growing bacteria, but decreased in slowly growing bacteria [Forchhammer & Lindahl (1971) J. Mol. Biol. 55, 563-568].

scholarly journals Effect of Temperature on In Vivo Protein Synthetic Capacity in Escherichia coli

1998 ◽  
Vol 180 (17) ◽  
pp. 4704-4710 ◽  
Author(s):  
Anne Farewell ◽  
Frederick C. Neidhardt
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
High Temperature ◽  
Low Temperature ◽  
Protein Degradation ◽  
Elongation Rate ◽  
Peptide Chain ◽  
Chain Elongation ◽  
Effect Of Temperature ◽  
Synthetic Capacity

ABSTRACT In this report, we examine the effect of temperature on protein synthesis. The rate of protein accumulation is determined by three factors: the number of working ribosomes, the rate at which ribosomes are working, and the rate of protein degradation. Measurements of RNA/protein ratios and the levels of individual ribosomal proteins and rRNA show that the cellular amount of ribosomal machinery in Escherichia coli is constant between 25 and 37°C. Within this range, in a given medium, temperature affects ribosomal function the same as it affects overall growth. Two independent methodologies show that the peptide chain elongation rate increases as a function of temperature identically to growth rate up to 37°C. Unlike the growth rate, however, the elongation rate continues to increase up to 44°C at the same rate as between 25 and 37°C. Our results show that the peptide elongation rate is not rate limiting for growth at high temperature. Taking into consideration the number of ribosomes per unit of cell mass, there is an apparent excess of protein synthetic capacity in these cells, indicating a dramatic increase in protein degradation at high temperature. Temperature shift experiments show that peptide chain elongation rate increases immediately, which supports a mechanism of heat shock response induction in which an increase in unfolded, newly translated protein induces this response. In addition, we find that at low temperature (15°C), cells contain a pool of nontranslating ribosomes which do not contribute to cell growth, supporting the idea that there is a defect in initiation at low temperature.

scholarly journals Specific Growth Rate Determines the Sensitivity of Escherichia coli to Thermal, UVA, and Solar Disinfection

2006 ◽  
Vol 72 (4) ◽  
pp. 2586-2593 ◽  
Author(s):  
Michael Berney ◽  
Hans-Ulrich Weilenmann ◽  
Julian Ihssen ◽  
Claudio Bassin ◽  
Thomas Egli
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Rates ◽  
Specific Growth ◽  
E Coli ◽  
Mild Heat ◽  
Uva Light ◽  
Specific Growth Rates ◽  
Slow Growing

ABSTRACT Knowledge about the sensitivity of the test organism is essential for the evaluation of any disinfection method. In this work we show that sensitivity of Escherichia coli MG1655 to three physical stresses (mild heat, UVA light, and sunlight) that are relevant in the disinfection of drinking water with solar radiation is determined by the specific growth rate of the culture. Batch- and chemostat-cultivated cells from cultures with similar specific growth rates showed similar stress sensitivities. Generally, fast-growing cells were more sensitive to the stresses than slow-growing cells. For example, slow-growing chemostat-cultivated cells (D = 0.08 h−1) and stationary-phase bacteria from batch culture that were exposed to mild heat had very similar T 90 (time until 90% of the population is inactivated) values (T 90, chemostat = 2.66 h; T 90, batch = 2.62 h), whereas T 90 for cells growing at a μ of 0.9 h−1 was 0.2 h. We present evidence that the stress sensitivity of E. coli is correlated with the intracellular level of the alternative sigma factor RpoS. This is also supported by the fact that E. coli rpoS mutant cells were more stress sensitive than the parent strain by factors of 4.9 (mild heat), 5.3 (UVA light), and 4.1 (sunlight). Furthermore, modeling of inactivation curves with GInaFiT revealed that the shape of inactivation curves changed depending on the specific growth rate. Inactivation curves of cells from fast-growing cultures (μ = 1.0 h−1) that were irradiated with UVA light showed a tailing effect, while for slow-growing cultures (μ = 0.3 h−1), inactivation curves with shoulders were obtained. Our findings emphasize the need for accurate reporting of specific growth rates and detailed culture conditions in disinfection studies to allow comparison of data from different studies and laboratories and sound interpretation of the data obtained.

scholarly journals Escherichia colipopulations adapt to complex, unpredictable fluctuations without any trade-offs across environments

2016 ◽  
Author(s):  
Shraddha Karve ◽  
Devika Bhave ◽  
Dhanashri Nevgi ◽  
Sutirth Dey
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Complex Environments ◽  
Multiple Stresses ◽  
Trade Off ◽  
Trade Offs ◽  
Fluctuating Environments ◽  
Laboratory Populations ◽  
Lower Variation

AbstractIn nature, organisms are simultaneously exposed to multiple stresses (i.e. complex environments) that often fluctuate unpredictably. While both these factors have been studied in isolation, the interaction of the two remains poorly explored. To address this issue, we selected laboratory populations ofEscherichia coliunder complex (i.e. stressful combinations of pH, H2O2and NaCl) unpredictably fluctuating environments for ~900 generations. We compared the growth rates and the corresponding trade-off patterns of these populations to those that were selected under constant values of the component stresses (i.e. pH, H2O2and NaCl) for the same duration. The fluctuation-selected populations had greater mean growth rate and lower variation for growth rate over all the selection environments experienced. However, while the populations selected under constant stresses experienced severe tradeoffs in many of the environments other than those in which they were selected, the fluctuation-selected populations could by-pass the across-environment trade-offs completely. Interestingly, trade-offs were found between growth rates and carrying capacities. The results suggest that complexity and fluctuations can strongly affect the underlying trade-off structure in evolving populations.

scholarly journals Wachstumsgeschwindigkeit der Peptidkette im Tabakmosaikvirus

1967 ◽  
Vol 22 (12) ◽  
pp. 1280-1291 ◽  
Author(s):  
H. Diringer ◽  
F. A. Anderer ◽  
G. Schramm
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Protein Synthesis ◽  
Peptide Chain ◽  
Cell Protein ◽  
Virus Protein ◽  
Animal Cells ◽  
Tobacco Leaves ◽  
Soluble Cell ◽  
C Terminus

The rate of incorporation of labelled amino acids into the complete tobacco mosaic virus (TMV), into soluble virus protein and into soluble cell proteins has been determined in discs of infected and healthy tobacco leaves. The rate of overall protein synthesis is increased by 50% in the infected leaves. At least 60% of the increase derives from the synthesis of virus-specific proteins and the synthesis of cellular proteins is not inhibited. The virus protein synthesis is strongly temperature dependent and shows a maximum at 28 °C.The exchange of free labelled amino acids between the external medium and the inner cellular pool reaches equilibrium within ten minutes. The influence of the exchange rate on the measurement of the kinetics of peptide chain synthesis is discussed in detail.Discs from infected leaves were incubated for short periods at low temperatures in media containing 3H-tyrosine or 3H-proline. Peptides isolated after 5 minutes incubation at 15 °C were found to be uniformly labelled with no apparent gradient of radioactivity from the N- to the C-terminus. The results indicate that the growth rate of the peptide chain at 15 °C is probably higher than 2 - 3 amino acids/sec and at 28 °C higher than 20 amino acids/sec. These values are higher than those for animal cells and similar to those for protein synthesis in Escherichia coli.Comparison of the growth rate of TMV protein with rate of total protein synthesis and the number of ribosomes in the tobacco leaves indicate that only a small portion of the ribosomes takes part in cell protein synthesis.

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.

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