Related Experiment Video
Updated: Dec 9, 2025
06:30
Using Microtiter Dish Radiolabeling for Multiple In Vivo Measurements Of Escherichia coli pppGpp Followed by Thin Layer Chromatography
Published on: June 4, 2019
6.3K
Diversity in E. coli (p)ppGpp Levels and Its Consequences
1Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Frontiers in Microbiology
|September 9, 2020
Summary
Intrinsic levels of guanosine tetraphosphate (ppGpp) vary widely in E. coli, impacting growth, stress tolerance, virulence, and antibiotic resistance. These variations are linked to genetic polymorphisms affecting ppGpp synthesis and hydrolysis.
Area of Science:
- Bacterial Physiology
- Molecular Biology
- Genetics
Background:
- The stringent response molecule, guanosine tetraphosphate (ppGpp), is a global regulator of bacterial physiology, controlling growth and adaptation.
- While essential for survival, intrinsic ppGpp levels are expected to be constant within a species, but genetic polymorphisms introduce variability.
- This variability influences bacterial responses to environmental challenges, including virulence and antimicrobial resistance.
Purpose of the Study:
- To review the variations in intrinsic ppGpp levels within the E. coli species.
- To explore the consequences of these variations on bacterial traits such as growth, stress tolerance, virulence, and antibiotic resistance.
Main Methods:
- Review of existing literature on ppGpp synthesis, hydrolysis, and regulation in E. coli.
- Analysis of studies investigating the correlation between intrinsic ppGpp levels and various phenotypic traits.
- Examination of genetic polymorphisms in genes related to ppGpp metabolism across different E. coli strains.
Main Results:
- Intrinsic ppGpp levels exhibit considerable variation across E. coli strains, often due to polymorphisms in genes controlling ppGpp metabolism.
- Higher intrinsic ppGpp levels are associated with reduced growth rates and increased tolerance to environmental stresses.
- Variations in ppGpp levels influence virulence factor production (e.g., Shiga toxin) and antimicrobial resistance.
Conclusions:
- Intrinsic ppGpp levels are a significant source of phenotypic diversity in E. coli.
- Understanding these variations is crucial for comprehending bacterial adaptation, pathogenesis, and treatment strategies.
- Targeting ppGpp metabolism could offer novel approaches for controlling E. coli infections and combating antibiotic resistance.
More Related Videos
Related Concept Videos
01:23Stringent Response in E. coli
196
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...
196
01:29Coordination of Gene Expression Processes in Bacteria
447
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...
447
01:28Global Regulatory Systems
406
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...
406
01:27Constitutive and Regulated Gene Expression
670
Gene expression in prokaryotes is governed by constitutive and regulated systems, allowing cells to balance the production of essential proteins with adaptive responses to environmental changes.Constitutive Gene ExpressionConstitutive, or housekeeping, genes are continuously expressed as they encode proteins vital for fundamental cellular processes. These include enzymes for glycolysis, ribosomal components for protein synthesis, and proteins involved in DNA replication. Their constant...
670
01:25Inducible Operons: lac Operon
1.0K
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA...
1.0K
01:28Gene Regulation in Microbial Communities: Quorum Sensing
335
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,...
335