Related Experiment Video
Updated: Apr 15, 2026
07:58
Laboratory Techniques Used to Maintain and Differentiate Biotypes of Vibrio cholerae Clinical and Environmental Isolates
Published on: May 30, 2017
11.6K
The Cpx system regulates virulence gene expression in Vibrio cholerae
Nicole Acosta1, Stefan Pukatzki2, Tracy L Raivio3
1Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Infection and Immunity
|April 1, 2015
Summary
The Cpx envelope stress response in Vibrio cholerae reduces major virulence factors, cholera toxin (CT) and toxin-coregulated pilus (TCP), by impacting the ToxT regulator and cyclic AMP receptor protein (CRP) function.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Signal Transduction
Background:
- Bacteria utilize signal transduction pathways to respond to environmental stimuli.
- The Cpx envelope stress response (CpxA/CpxR) is crucial for bacterial adaptation to envelope insults.
- This pathway influences virulence factors in various bacterial species.
Purpose of the Study:
- To investigate the role of the Cpx pathway in regulating virulence factors in Vibrio cholerae.
- To elucidate the molecular mechanisms by which Cpx affects cholera toxin (CT) and toxin-coregulated pilus (TCP) production.
Main Methods:
- Activation of the Cpx pathway in Vibrio cholerae El Tor strain C6706.
- Analysis of virulence factor gene expression (CT and TCP).
- Assessment of regulator proteins (ToxT, TcpP) and cyclic AMP receptor protein (CRP) function.
Main Results:
- Cpx pathway activation decreased CT and TCP expression.
- This decrease was mediated by repression of ToxT and TcpP.
- The Cpx effect on CT and TCP was largely dependent on functional CRP, suggesting Cpx influences CRP activity.
Conclusions:
- The Cpx response negatively regulates key Vibrio cholerae virulence factors.
- The mechanism involves interference with CRP-mediated regulation of TcpP, leading to reduced ToxT, CT, and TCP production.
- This highlights a novel regulatory link between envelope stress response and virulence in Vibrio cholerae.
Related Concept Videos
01:28Regulation of Bacterial Virulence
57
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...
57
01:25Cholera
92
Cholera is an acute gastrointestinal disease caused by the Gram-negative bacterium Vibrio cholerae. It is transmitted primarily via the fecal-oral route through the ingestion of contaminated water or food.Vibrio cholerae is a motile, Gram-negative bacterium of the family Vibrionaceae, primarily associated with waterborne outbreaks in areas with inadequate sanitation. Although over 200 serogroups of V. cholerae exist, only O1 and O139 are responsible for epidemic cholera. The O1 serogroup,...
92
01:17Gram-negative Bacterial Protein Secretion Systems
1.6K
Gram-negative bacteria utilize sophisticated protein secretion systems to transport proteins across their double-membrane envelope into the extracellular environment or host cells. Based on their mechanism of action, these systems are classified into one-step and two-step pathways.One-Step Secretion Systems (Types I, III, IV, and VI)One-step secretion systems bypass the periplasm entirely, forming a continuous channel that spans both the inner and outer membranes:Type I Secretion System (T1SS):...
1.6K
01:23Stringent Response in E. coli
492
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...
492
01:29Coordination of Gene Expression Processes in Bacteria
1.0K
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
1.0K
01:28Gene Regulation in Microbial Communities: Quorum Sensing
923
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
923