Mechanism responsible for glucose–lactose diauxie in Escherichia coli: challenge to the cAMP model

@article{Inada1996MechanismRF,
  title={Mechanism responsible for glucose–lactose diauxie in Escherichia coli: challenge to the cAMP model},
  author={Toshifumi Inada and Keiko Kimata and Hiroji Aiba},
  journal={Genes to Cells},
  year={1996},
  volume={1}
}
BACKGROUND The inhibition of beta-galactosidase expression in glucose-lactose diauxie is a typical example of the glucose effect in Escherichia coli. [] Key Result We found that the levels of cAMP and CRP in a lactose-grown phase were not higher than those in a glucose-grown phase, although the cAMP levels increased transiently during the lag phase. The addition of exogenous cAMP eliminated diauxic growth but did not eliminate glucose repression.

Mathematical Description of the Lac Operon Regulation in Diauxic and Non-Diauxic Growth on Glucose and Lactose

  • Lili LuH. Lou
  • Biology
    2009 3rd International Conference on Bioinformatics and Biomedical Engineering
  • 2009
Two mathematical models for the regulation of the lac operon are presented and a new mechanism for catabolite repression is tested: cyclic AMP synthesis is correlated not only with the external glucose concentration but also with the internal glucose concentration.

cAMP receptor protein-cAMP plays a crucial role in glucose-lactose diauxie by activating the major glucose transporter gene in Escherichia coli.

It is concluded that CRP-cAMP plays a crucial role in inducer exclusion, which is responsible for the glucose-lactose diauxie, by activating the expression of the ptsG gene.

Catabolite repression by glucose 6‐phosphate, gluconate and lactose in Escherichia coli

It is shown that enzyme IIAGlc of the PTS is not involved in catabolite repression by non‐PTS carbon sources, and both the cAMP and the CRP levels are lowered by glucose 6‐phosphate, lactose and gluconate.

Deconstructing glucose-mediated catabolite repression of the lac operon of Escherichia coli: II. Positive feedback exists and drives the repression

Methods for determining the intracellular allolactose concentration as well as the kinetics of enzyme induction and dilution are developed, showing that during lac induction in the presence of lactose, the intrasease concentration increases with the lactose enzyme level, which implies that lactose enzymes promote allolACTose accumulation, and positive feedback exists.

Autoregulation of lactose uptake through the LacYpermease by enzyme IIAGlc of the PTS in Escherichia coli K‐12

The autoregulatory mechanism that controls lactose uptake is an important mechanism for the cells in adjusting the uptake rate to their metabolic capacity.

Coupling Physiology and Gene Regulation in Bacteria: The Phosphotransferase Sugar Uptake System Delivers the Signals

These recent results establish a multifaceted regulatory role for PTS in addition to its well-established function in active sugar uptake in gram-positive bacteria.

The organization of metabolic reaction networks. III. Application for diauxic growth on glucose and lactose.

A mathematical model to describe carbon catabolite repression in Escherichia coli is developed and in part validated and all experiments could be sufficiently described with a single set of parameters.

Carbon catabolite repression in bacteria.

Is there any role for cAMP–CRP in carbon catabolite repression of the Escherichia coli lac operon? Reply from Görke and Stülke

Is there any role for cAMP–CRP in carbon catabolite repression of the Escherichia coli lac operon? Reply from Gorke and Stulke
...

References

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The ability of glucose to prevent expression of the lac operon by reducing the internal concentration of inducer as well as by catabolite repression is discussed.

Chapter IX: Glucose Effects: Inducer Exclusion and Repression

It is shown in this chapter that glucose interferes with the synthesis of β -galactosidase in inducible strains of E. coli in three ways: it excludes the inducer from cells that do not contain a high level of the lac y gene controlled permease; it represses β-galactsidase strongly, but transiently, when added to cells growing on another source of carbon (transient repression).

Glucose lowers CRP* levels resulting in repression of the lac operon in cells lacking cAMP

The data strongly suggest that the lowered level of CRP* caused by glucose mediates catabolite repression in cya− crp* cells and that the autoregulatory circuit of the crp gene is involved in the down‐regulation ofCRP* expression by glucose.

Cyclic AMP as an antagonist of catabolite repression in Escherichia coli

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The concentration of cyclic adenosine 3',5'-monophosphate in Escherichia coli growing on different sources of carbon was studied and transient repression of the synthesis of beta-galactosidase was not associated with an abrupt decrease in the cellular concentration of c-AMP.

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Adenosine 3':5'-cyclic monophosphate as mediator of catabolite repression in Escherichia coli.

Measurements of intracellular adenosine 3':5'-cyclic monophosphate (cAMP) concentrations in E. coli under a variety of conditions show that levels of this nucleotide are well correlated with the rate of synthesis of beta-galactosidase, providing strong support for the concept that intrACEllular cAMP levels mediate the effects of catabolite and transient repression on rates on enzyme synthesis.

Mechanism of the down‐regulation of cAMP receptor protein by glucose in Escherichia coli: role of autoregulation of the crp gene.

It is shown that disrupting the CRP binding site II essentially eliminates the down‐regulation of crp expression by glucose and concludes that the autoregulatory circuit of the crp gene plays a key role in the down-regulation of CRP by glucose.