Dataset Information

Fine-tuning of chemotactic response in E. coli determined by high-throughput capillary assay.

ABSTRACT: In E. coli, chemotactic behavior exhibits perfect adaptation that is robust to changes in the intracellular concentration of the chemotactic proteins, such as CheR and CheB. However, the robustness of the perfect adaptation does not explicitly imply a robust chemotactic response. Previous studies on the robustness of the chemotactic response relied on swarming assays, which can be confounded by processes besides chemotaxis, such as cellular growth and depletion of nutrients. Here, using a high-throughput capillary assay that eliminates the effects of growth, we experimentally studied how the chemotactic response depends on the relative concentration of the chemotactic proteins. We simultaneously measured both the chemotactic response of E. coli cells to L: -aspartate and the concentrations of YFP-CheR and CheB-CFP fusion proteins. We found that the chemotactic response is fine-tuned to a specific ratio of [CheR]/[CheB] with a maximum response comparable to the chemotactic response of wild-type behavior. In contrast to adaptation in chemotaxis, that is robust and exact, capillary assays revealed that the chemotactic response in swimming bacteria is fined-tuned to wild-type level of the [CheR]/[CheB] ratio.

SUBMITTER: Park H

PROVIDER: S-EPMC3230253 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Fine-tuning of chemotactic response in E. coli determined by high-throughput capillary assay.

Park Heungwon H Guet Calin C CC Emonet Thierry T Cluzel Philippe P

Current microbiology 20101024 3

In E. coli, chemotactic behavior exhibits perfect adaptation that is robust to changes in the intracellular concentration of the chemotactic proteins, such as CheR and CheB. However, the robustness of the perfect adaptation does not explicitly imply a robust chemotactic response. Previous studies on the robustness of the chemotactic response relied on swarming assays, which can be confounded by processes besides chemotaxis, such as cellular growth and depletion of nutrients. Here, using a high-t ...[more]

PMID: 20972792

Similar Datasets

Project description:UNLABELLED:The envelope of Gram-negative bacteria is an essential compartment that constitutes a protective and permeability barrier between the cell and its environment. The envelope also hosts the cell wall, a mesh-like structure made of peptidoglycan (PG) that determines cell shape and provides osmotic protection. Since the PG must grow and divide in a cell-cycle-synchronized manner, its synthesis and remodeling are tightly regulated. Here, we discovered that PG homeostasis is intimately linked to the levels of activation of the Cpx system, an envelope stress response system traditionally viewed as being involved in protein quality control in the envelope. We first show that Cpx is activated when PG integrity is challenged and that this activation provides protection to cells exposed to antibiotics inhibiting PG synthesis. By rerouting the outer membrane lipoprotein NlpE, a known Cpx activator, to a different envelope subcompartment, we managed to manipulate Cpx activation levels. We found that Cpx overactivation leads to aberrant cellular morphologies, to an increased sensitivity to ?-lactams, and to dramatic division and growth defects, consistent with a loss of PG homeostasis. Remarkably, these phenotypes were largely abrogated by the deletion of ldtD, a Cpx-induced gene involved in noncanonical PG cross-linkage, suggesting that this transpeptidase is an important link between PG homeostasis and the Cpx system. Altogether our data show that fine-tuning of an envelope quality control system constitutes an important layer of regulation of the highly organized cell wall structure. IMPORTANCE:The envelope of Gram-negative bacteria is essential for viability. First, it includes the cell wall, a continuous polymer of peptidoglycan (PG) that determines cell morphology and protects against osmotic stress. Moreover, the envelope constitutes a protective barrier between the cell interior and the environment. Therefore, mechanisms called envelope stress response systems (ESRS) exist to monitor and defend envelope integrity against harmful conditions. Cpx is a major ESRS that detects and manages the accumulation of misfolded proteins in the envelope of Escherichia coli. We found that this protein quality control system also plays a fundamental role in the regulation of PG assembly. Strikingly, the level of Cpx response is critical, as an excessive activation leads to phenotypes associated with a loss of cell wall integrity. Thus, by contributing to PG homeostasis, the Cpx system lies at the crossroads between key processes of bacterial life, including cell shape, growth, division, and antibiotic resistance.

Dataset Information

Fine-tuning of chemotactic response in E. coli determined by high-throughput capillary assay.

Publications

Fine-tuning of chemotactic response in E. coli determined by high-throughput capillary assay.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets