scholarly journals Escherichia coli Physiology in Luria-Bertani Broth

2007 ◽  
Vol 189 (23) ◽  
pp. 8746-8749 ◽  
Author(s):  
Guennadi Sezonov ◽  
Danièle Joseleau-Petit ◽  
Richard D'Ari
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Growth Rate ◽  
Steady State ◽  
Cell Mass ◽  
Carbon Sources ◽  
Luria Bertani ◽  
E Coli ◽  
Luria Bertani Broth ◽  
State Growth

ABSTRACT Luria-Bertani broth supports Escherichia coli growth to an optical density at 600 nm (OD600) of 7. Surprisingly, however, steady-state growth ceases at an OD600 of 0.3, when the growth rate slows down and cell mass decreases. Growth stops for lack of a utilizable carbon source. The carbon sources for E. coli in Luria-Bertani broth are catabolizable amino acids, not sugars.

scholarly journals Role of the sRNA GcvB in regulation of cycA in Escherichia coli

Microbiology ◽  
2009 ◽  
Vol 155 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Sarah C. Pulvermacher ◽  
Lorraine T. Stauffer ◽  
George V. Stauffer
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Minimal Medium ◽  
Luria Bertani ◽  
Cell Physiology ◽  
Rt Pcr ◽  
Luria Bertani Broth ◽  
Increased Sensitivity ◽  
Transcriptional Fusions

In Escherichia coli, the gcvB gene encodes a small non-translated RNA that regulates several genes involved in transport of amino acids and peptides (including sstT, oppA and dppA). Microarray analysis identified cycA as an additional regulatory target of GcvB. The cycA gene encodes a permease for the transport of glycine, d-alanine, d-serine and d-cycloserine. RT-PCR confirmed that GcvB and the Hfq protein negatively regulate cycA mRNA in cells grown in Luria–Bertani broth. In addition, deletion of the gcvB gene resulted in increased sensitivity to d-cycloserine, consistent with increased expression of cycA. A cycA : : lacZ translational fusion confirmed that GcvB negatively regulates cycA expression in Luria–Bertani broth and that Hfq is required for the GcvB effect. GcvB had no effect on cycA : : lacZ expression in glucose minimal medium supplemented with glycine. However, Hfq still negatively regulated the fusion in the absence of GcvB. A set of transcriptional fusions of cycA to lacZ identified a sequence in cycA necessary for regulation by GcvB. Analysis of GcvB identified a region complementary to this region of cycA mRNA. However, mutations predicted to disrupt base-pairing between cycA mRNA and GcvB did not alter expression of cycA : : lacZ. A model for GcvB function in cell physiology is discussed.

scholarly journals Multiple Roles for the sRNA GcvB in the Regulation of Slp Levels in Escherichia coli

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Lorraine T. Stauffer ◽  
George V. Stauffer
Keyword(s):  
Escherichia Coli ◽  
Luria Bertani ◽  
Multiple Roles ◽  
Activation Mechanism ◽  
Mrna Levels ◽  
Rt Pcr ◽  
E Coli ◽  
Luria Bertani Broth ◽  
Outer Membrane Lipoprotein ◽  
Membrane Lipoprotein

The Escherichia coli gcvB gene encodes a small RNA that regulates many genes involved in the transport of dipeptides, oligopeptides, and amino acids (oppA, dppA, cycA, and sstT). A microarray analysis of RNA isolated from an E. coli wild-type and a ΔgcvB strain grown to midlog phase in Luria-Bertani broth indicated that genes not involved in transport are also regulated by GcvB. One gene identified was slp that encodes an outer membrane lipoprotein of unknown function induced when cells enter stationary phase. The aim of this study was to verify that slp is a new target for GcvB-mediated regulation. In this study we used RT-PCR to show that GcvB regulates slp mRNA levels. GcvB negatively controls slp::lacZ in cells grown in Luria-Bertani broth by preventing an Hfq-mediated activation mechanism for slp::lacZ expression. In contrast, in glucose minimal medium supplemented with glycine, GcvB is required for inhibition of slp::lacZ expression, and Hfq prevents GcvB-mediated repression. Thus, GcvB regulates slp in both LB and in glucose minimal + glycine media and likely by mechanisms different than how it regulates sstT, dppA, cycA, and oppA. Repression of slp by GcvB results in an increase in resistance to chloramphenicol, and overexpression of slp in a ΔgcvB strain results in an increase in sensitivity to chloramphenicol.

Aer and Tsr guide Escherichia coli in spatial gradients of oxidizable substrates

Microbiology ◽  
2003 ◽  
Vol 149 (9) ◽  
pp. 2661-2667 ◽  
Author(s):  
Suzanne E. Greer-Phillips ◽  
Gladys Alexandre ◽  
Barry L. Taylor ◽  
Igor B. Zhulin
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Carbon Sources ◽  
Proton Motive Force ◽  
Maximal Growth ◽  
Phosphotransferase System ◽  
E Coli ◽  
Spatial Gradients ◽  
Energy Taxis ◽  
Effective Growth

The Aer and Tsr chemoreceptors in Escherichia coli govern tactic responses to oxygen and redox potential that are parts of an overall behaviour known as energy taxis. They are also proposed to mediate responses to rapidly utilized carbon sources, glycerol and succinate, via the energy taxis mechanism. In this study, the Aer and Tsr proteins were individually expressed in an ‘all-transducer-knockout’ strain of E. coli and taxis was analysed in gradients of various oxidizable carbon sources. In addition to the known response to glycerol and succinate, it was found that Aer directed taxis towards ribose, galactose, maltose, malate, proline and alanine as well as the phosphotransferase system (PTS) carbohydrates glucose, mannitol, mannose, sorbitol and fructose, but not to aspartate, glutamate, glycine and arabinose. Tsr directed taxis towards sugars (including those transported by the PTS), but not to organic acids or amino acids. When a mutated Aer protein unable to bind the FAD cofactor was expressed in the receptor-less strain, chemotaxis was not restored to any substrate. Aer appears to mediate responses to rapidly oxidizable substrates, whether or not they are effective growth substrates, whereas Tsr appears to mediate taxis to substrates that support maximal growth, whether or not they are rapidly oxidizable. This correlates with the hypothesis that Aer and Tsr sense redox and proton motive force, respectively. Taken together, the results demonstrate that Aer and Tsr mediate responses to a broad range of chemicals and their attractant repertoires overlap with those of specialized chemoreceptors, namely Trg (ribose, galactose) and Tar (maltose).

Relationship between Bdellovibrio bacteriovorus 6-5-S and autoclaved host bacteria

1972 ◽  
Vol 18 (12) ◽  
pp. 1941-1948 ◽  
Author(s):  
S. F. Crothers ◽  
H. B. Fackrell ◽  
J. C. C. Huang ◽  
J. Robinson
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Growth Rate ◽  
Reducing Sugars ◽  
Culture Fluid ◽  
Amino Sugars ◽  
Buffer Solution ◽  
Bdellovibrio Bacteriovorus ◽  
Initial Concentration ◽  
E Coli

Bdellovibrio bacteriovorus, strain 6-5-S, multiplied in the presence of washed suspensions of Escherichia coli, Spirillum serpens VHL, and Bacillus megaterium which had been autoclaved for 5 min at 121C. No intracellular life cycle was observed. Bdellovibrio bacteriovorus was also able to multiply in an extract from autoclaved E. coli cells after the cells had been removed by centrifugation. Growth of the parasite was dependent upon the addition of Ca2+ and Mg2+ to the buffer solution. The growth rate and yield of B. bacteriovorus on autoclaved cells were not affected by the initial concentration of the parasite. During multiplication of B. bacteriovorus, amino acids, amino sugars, and reducing sugars were released into the culture fluid.

Effects of culture conditions on yield of Shiga-like toxin-IIv from Escherichia coli

1989 ◽  
Vol 35 (6) ◽  
pp. 623-629 ◽  
Author(s):  
D. L. MacLeod ◽  
C. L. Gyles
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Mitomycin C ◽  
Incubation Temperature ◽  
Culture Media ◽  
Carbon Sources ◽  
Culture Conditions ◽  
Edema Disease ◽  
E Coli ◽  
Aerobic Culture

The effects of selected culture conditions on production of Shiga-like toxin-II variant by an edema disease strain of Escherichia coli (412) and E. coli TB1 (pCG6) containing the cloned genes for Shiga-like toxin-II variant were examined. Incubation time, culture media, incubation temperature, starting pH of the culture medium, aeration, static culture, anaerobiosis, carbon sources, amino acids, antibiotics, and mitomycin C were investigated. The study showed that Shiga-like toxin-II variant was primarily cell associated and that strain TB1 (pCG6) produced as much as 100 times more toxin than did strain 412. Culture conditions that resulted in the greatest yield of Shiga-like toxin-II variant were incubation at 37 °C for 24 h with shaking in syncase broth initially adjusted to pH 8.5. Aerobic culture with shaking resulted in higher yields of Shiga-like toxin-II variant than did static aerobic or anaerobic culture. Addition of various carbon sources or amino acids, or tetracycline, lincomycin, or trimethoprim: sulfadoxine did not increase yields of toxin. The amount of Shiga-like toxin-II variant in supernatant preparations from strain TB1 (pCG6) was significantly increased by addition of mitomycin C to the culture medium.Key words: Shiga-like toxin-II variant, verotoxin, Escherichia coli, edema disease, culture conditions.

Growth kinetics of Escherichia coli with galactose and several other sugars in carbon-limited chemostat culture

1999 ◽  
Vol 46 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Urs Lendenmann ◽  
Mario Snozzi ◽  
Thomas Egli
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Steady State ◽  
Specific Growth Rate ◽  
Growth Kinetics ◽  
Specific Growth ◽  
Chemostat Culture ◽  
Monod Model ◽  
E Coli ◽  
Kinetics Of

Kinetic models for microbial growth describe the specific growth rate (μ) as a function of the concentration of the growth-limiting nutrient (s) and a set of parameters. A typical example is the model proposed by Monod, where μ is related to s using substrate affinity (Ks) and the maximum specific growth rate (μmax). The preferred method to determine such parameters is to grow microorganisms in continuous culture and to measure the concentration of the growth-limiting substrate as a function of the dilution rate. However, owing to the lack of analytical methods to quantify sugars in the microgram per litre range, it has not been possible to investigate the growth kinetics of Escherichia coli in chemostat culture. Using an HPLC method able to determine steady-state concentrations of reducing sugars, we previously have shown that the Monod model adequately describes glucose-limited growth of E. coli ML30. This has not been confirmed for any other sugar. Therefore, we carried out a similar study with galactose and found steady-state concentrations between 18 and 840 μg·L-1 for dilution rates between 0.2 and 0.8·h-1, respectively. With these data the parameters of several models giving the specific growth rate as a function of the substrate concentration were estimated by nonlinear parameter estimation, and subsequently, the models were evaluated statistically. From all equations tested, the Monod model described the data best. The parameters for galactose utilisation were μmax = 0.75·h-1 and Ks = 67 μg·L-1. The results indicated that accurate Ks values can be estimated from a limited set of steady-state data when employing μmax measured during balanced growth in batch culture. This simplified procedure was applied for maltose, ribose, and fructose. For growth of E. coli with these sugars, μmax and Ks were for maltose 0.87·h-1, 100 μg·L-1; for ribose 0.57·h-1, 132 μg·L-1, and for fructose 0.70·h-1, 125 μg·L-1. Key words: monod model, continuous culture, galactose, glucose, fructose, maltose, ribose.

Growth History Influences Starvation-Induced Expression of uspA, grpE, and rpoS and Subsequent Cryotolerance in Escherichia coli O157:H7

2005 ◽  
Vol 68 (6) ◽  
pp. 1154-1158 ◽  
Author(s):  
PURUSHOTTAM V. GAWANDE ◽  
MANSEL W. GRIFFITHS
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Molecular Mechanisms ◽  
Frozen Storage ◽  
Luria Bertani ◽  
Growth Media ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Luria Bertani Broth ◽  
And Control

In this study, we investigated the effect of starvation on cryotolerance of Escherichia coli O157:H7 grown in tryptic soy broth (TSB) and Luria-Bertani broth (LB). Starved cells (cells suspended in water at 37°C for 6 h) and control cells (cells in TSB or LB) were frozen at −18°C for up to 240 h in their respective growth media. The E. coli grown in TSB showed a greater starvation effect (the difference in percent survival of starved and control cells) and cryotolerance. The starved E. coli grown in TSB showed a 30% increase in their ability to survive frozen storage for 24 h at −18°C. The corresponding increase in survival for LB-grown E. coli was only 3.8%. Cryotolerance induced by starvation of TSB- and LB-grown E. coli was correlated with the expression of genes involved in general stress response pathways, such as uspA, grpE, and rpoS. The expression of uspA, grpE, and rpoS was quantified by measuring the green fluorescence generated from autofluorescent E. coli harboring puspA::gfp, pgrpE::gfp, and prpoS::gfp gene fusions. The results obtained in this study indicate that uspA, grpE, and rpoS were induced on starvation when E. coli was grown in TSB, and their expression correlated well with subsequent induction of cryotolerance developed at −18°C. In contrast, cells grown in LB and subsequently exposed to starvation conditions showed no increase in expression of uspA, grpE, or rpoS, and, as expected, these cells did not exhibit increased cryotolerance at −18°C. Knowledge of molecular mechanisms involved in cross-protection might make it possible to devise strategies to limit their effects and lead to ways to predict the survival of foodborne pathogens in stressful environments.

scholarly journals Flagellin of Enteropathogenic Escherichia coli Stimulates Interleukin-8 Production in T84 Cells

2003 ◽  
Vol 71 (4) ◽  
pp. 2120-2129 ◽  
Author(s):  
Xin Zhou ◽  
Jorge A. Girón ◽  
Alfredo G. Torres ◽  
J. Adam Crawford ◽  
Erasmo Negrete ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Luria Bertani ◽  
Interleukin 8 ◽  
Epec Strain ◽  
T84 Cells ◽  
E Coli ◽  
Luria Bertani Broth ◽  
Mitogen Activated Protein ◽  
K 12

ABSTRACT The type III secretion system (TTSS) of enteropathogenic Escherichia coli (EPEC) has been associated with the ability of these bacteria to induce secretion of proinflammatory cytokines, including interleukin-8 (IL-8), in cultured epithelial cells. However, the identity of the effector molecule directly involved in this event is unknown. In this study, we determined that the native flagellar filament and its flagellin monomer are activators of IL-8 release in T84 epithelial cells. Supernatants of wild-type EPEC strain E2348/69 and its isogenic mutants deficient in TTSS (escN) and in production of intimin (eae), grown in Luria-Bertani broth, elicited similar amounts of IL-8 secretion by T84 cells. In contrast, supernatants of EPEC fliC mutants and of B171, a nonflagellated EPEC strain, were defective in inducing IL-8 release, a phenotype that was largely restored by complementation of the fliC gene in the mutant lacking flagella. Purified flagella from E. coli K-12, EPEC serotypes H6 and H34, and enterohemorrhagic E. coli serotype H7 all induced IL-8 release in T84 cells. Induction of IL-8 by purified flagella or His-tagged FliC from EPEC strain E2348/69 was dose dependent and was blocked by a polyclonal anti-H6 antibody. Finally, the mitogen-activated protein kinases (Erk1 and -2 and Jnk) were phosphorylated in flagellin-treated T84 cells, and inhibition of the p38 and Erk pathways significantly decreased the IL-8 response induced by EPEC flagellin. Our data clearly indicate that FliC of EPEC is sufficient to induce IL-8 release in T84 cells and that activation of the Erk and p38 pathways is required for IL-8 induction.

scholarly journals Osmotolerance in Escherichia coli Is Improved by Activation of Copper Efflux Genes or Supplementation with Sulfur-Containing Amino Acids

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Mengyong Xiao ◽  
Xinna Zhu ◽  
Feiyu Fan ◽  
Hongtao Xu ◽  
Jinlei Tang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Osmotic Stress ◽  
Cell Mass ◽  
Anaerobic Conditions ◽  
Two Component System ◽  
Content Type ◽  
E Coli ◽  
Sulfur Containing ◽  
Disodium Succinate

ABSTRACT Improvement in the osmotolerance of Escherichia coli is essential for the production of high titers of various bioproducts. In this work, a cusS mutation that was identified in the previously constructed high-succinate-producing E. coli strain HX024 was investigated for its effect on osmotolerance. CusS is part of the two-component system CusSR that protects cells from Ag(I) and Cu(I) toxicity. Changing cusS from strain HX024 back to its original sequence led to a 24% decrease in cell mass and succinate titer under osmotic stress (12% glucose). When cultivated with a high initial glucose concentration (12%), introduction of the cusS mutation into parental strain Suc-T110 led to a 21% increase in cell mass and a 40% increase in succinate titer. When the medium was supplemented with 30 g/liter disodium succinate, the cusS mutation led to a 120% increase in cell mass and a 492% increase in succinate titer. Introducing the cusS mutation into the wild-type strain ATCC 8739 led to increases in cell mass of 87% with 20% glucose and 36% using 30 g/liter disodium succinate. The cusS mutation increased the expression of cusCFBA, and gene expression levels were found to be positively related to osmotolerance abilities. Because high osmotic stress has been associated with deleterious accumulation of Cu(I) in the periplasm, activation of CusCFBA may alleviate this effect by transporting Cu(I) out of the cells. This hypothesis was confirmed by supplementing sulfur-containing amino acids that can chelate Cu(I). Adding methionine or cysteine to the medium increased the osmotolerance of E. coli under anaerobic conditions. IMPORTANCE In this work, an activating Cus copper efflux system was found to increase the osmotolerance of E. coli. In addition, new osmoprotectants were identified. Supplementation with methionine or cysteine led to an increase in osmotolerance of E. coli under anaerobic conditions. These new strategies for improving osmotolerance will be useful for improving the production of chemicals in industrial bioprocesses.

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