Related Experiment Video

Updated: May 23, 2026

Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing
09:44

Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing

Published on: December 23, 2022

SoxS-dependent coregulation of ompN and ydbK in a multidrug-resistant Escherichia coli strain

Anna Fàbrega1, Judah L Rosner, Robert G Martin

  • 1Barcelona Centre for International Health Research, CRESIB, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain.

FEMS Microbiology Letters
|April 21, 2012
PubMed

Insights

SoxS activates the ydbK-ompN operon indirectly, contributing to superoxide resistance via YdbK. Neither gene confers antibiotic resistance in Escherichia coli.

Area of Science:

  • Molecular Biology
  • Microbiology
  • Genetics

Background:

  • SoxS, MarA, and Rob are transcriptional activators regulating superoxide and antibiotic resistance genes.
  • Many genes regulated by these activators remain uncharacterized, particularly in multidrug-resistant strains.

Purpose of the Study:

  • To investigate the regulation of the ompN porin and its upstream gene, ydbK, in Escherichia coli.
  • To determine the role of SoxS, MarA, and Rob in the activation of ydbK and ompN.
  • To elucidate the contribution of ydbK and ompN to superoxide and antibiotic resistance.

Main Methods:

  • Microarray analysis and RT-PCR to assess gene expression.
  • Transcriptional fusions to identify promoter activation.
  • Bioinformatic analysis to predict regulatory elements.
  • Mutant susceptibility testing for superoxide and antibiotic resistance.

Main Results:

  • SoxS overexpression led to increased ydbK and ompN expression in a multidrug-resistant E. coli strain.
  • SoxS directly activated the ydbK promoter but not the ompN upstream region, suggesting indirect activation of ompN.
  • ydbK and ompN are co-expressed as an operon, activated indirectly by SoxS.
  • Only ydbK mutants showed susceptibility to paraquat (superoxide generator); neither gene conferred antibiotic resistance.

Conclusions:

  • The ydbK-ompN operon is indirectly activated by SoxS.
  • YdbK plays a significant role in superoxide resistance.
  • Neither ydbK nor ompN contributes to the antibiotic resistance phenotypes tested.

More Related Videos

Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays14:06

Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays

Published on: November 12, 2012

A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis06:30

A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis

Published on: January 27, 2021

Related Concept Videos

Stringent Response in E. coli01:23

Stringent Response in E. coli

Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Global Regulatory Systems01:28

Global Regulatory Systems

Global regulatory systems in bacteria enable rapid and coordinated responses to environmental changes by integrating sensory inputs with gene expression, ensuring efficient adaptation to fluctuating conditions. Key global regulatory mechanisms include regulons, two-component systems, sigma factors, and secondary messengers.Regulons and Global RegulatorsA regulon is a collection of genes and operons controlled by a common global regulator. These regulators enable bacteria to prioritize resource...
Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
Bacterial Translocation and Protein Secretion01:26

Bacterial Translocation and Protein Secretion

Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...
Operon Model01:23

Operon Model

The operon model represents a fundamental mechanism of gene regulation in prokaryotes, enabling coordinated expression of genes involved in related metabolic or functional pathways. Operons consist of structural genes, a promoter, and an operator, with transcription regulated by repressors, activators, and small effector molecules.Structure and Function of OperonsAn operon is a cluster of structural genes transcribed together under the control of a single promoter. The promoter region...