Related Experiment Video
Updated: Sep 11, 2025
05:06
Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System
Published on: January 5, 2024
723
Functional interplay between RND efflux pumps and GacS in Pseudomonas aeruginosa
Justyna W Adamiak1, Charles Bergen1, Laiba Ajmal1
1Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA.
Applied and Environmental Microbiology
|August 18, 2025
Summary
This study reveals that Resistance-Nodulation-Division (RND) efflux pumps and the GacSA system in Pseudomonas aeruginosa have overlapping functions. Their combined action influences antibiotic resistance and virulence, especially under infection-like conditions.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Pseudomonas aeruginosa possesses significant environmental adaptability due to efflux pumps and regulatory systems.
- Resistance-Nodulation-Division (RND) transporters are crucial for antibiotic resistance and stress survival.
- The GacSA system globally regulates P. aeruginosa lifestyles and colonization.
Purpose of the Study:
- To investigate the functional interplay between RND efflux pumps and the GacSA two-component system in P. aeruginosa.
- To understand how these systems influence bacterial lifestyle, virulence, and metabolism.
Main Methods:
- Comparative transcriptomic analysis of P. aeruginosa strains with inactivated RND pumps or gacS.
- Assessment of gene expression changes during exponential and stationary growth phases.
- Evaluation of gene expression and growth under conditions mimicking human infections (elevated temperature, iron deprivation).
Main Results:
- Inactivation of RND pumps or gacS led to broad, overlapping transcriptional responses in lifestyle, virulence, and metabolic pathways.
- Responses were more pronounced during the exponential growth phase.
- GacSA and RND efflux pumps exhibited opposing effects on gene expression, but GacS overexpression was additive with efflux pump deletion under specific conditions.
Conclusions:
- RND efflux pumps and the GacSA regulatory network exhibit partial functional overlap in P. aeruginosa.
- These pathways are potentially complementary, contributing to bacterial survival in hostile environments.
- Understanding these interactions is vital for combating P. aeruginosa infections and antibiotic resistance.
Related Concept Videos
01:28Gene Regulation in Microbial Communities: Quorum Sensing
92
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,...
92
01:09GPCRs Regulate Adenylyl Cylase Activity
5.9K
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of...
5.9K
01:25Rab Cascades
2.7K
Rab GTPases act in a regulated cascade during membrane fusion, helping the lipid bilayers mix. The Rab family of proteins are active when bound to GTP, and inactive when bound to GDP. Hence, they act as guanine nucleotide-dependent molecular switches. Rab-GTP recognizes and binds to long or short-range tethering proteins to capture the target vesicle. These tethers coordinate with SNAREs on the vesicle and the target membrane to assemble the trans SNARE complex that locks the mixing bilayers.
2.7K
01:28Global Regulatory Systems
71
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...
71
01:14Rab Proteins
4.1K
Rab proteins constitute the largest family of monomeric GTPases, of which 70 members are present in humans. Rab proteins and their effectors regulate consecutive stages of vesicle transport such as vesicle transport, docking, and fusion to the correct recipient membrane.
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
4.1K
01:23Stringent Response in E. coli
52
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...
52