Related Experiment Video

Updated: Feb 18, 2026

Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans
09:36

Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans

Published on: March 23, 2019

7.7K

Transcriptome responses of Streptococcus mutans to peroxide stress: identification of novel antioxidant pathways

Jessica K Kajfasz1, Tridib Ganguly1, Emily L Hardin1

  • 1Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, 32608, USA.

Scientific Reports
|November 24, 2017
PubMed

Insights

Streptococcus mutans SpxA1 regulates genes involved in peroxide stress response, impacting metabolism and antioxidant production. This study expands the known oxidative stress genes in S. mutans.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacterial Stress Response

Background:

  • The oxidative stress regulator Spx is common in Gram-positive bacteria.
  • In Streptococcus mutans, SpxA1 is the primary activator of oxidative stress genes, with SpxA2 playing a backup role.

Purpose of the Study:

  • To uncover the full scope of the hydrogen peroxide (H₂O₂) stress regulon in S. mutans.
  • To further investigate the role of Spx regulation in S. mutans' response to peroxide stress.

Main Methods:

  • RNA sequencing (transcriptome analysis) was employed to identify genes regulated by Spx during peroxide stress.
  • Phenotype enhancement screening of double mutants was used to identify genes critical for stress survival.
  • Physiological and biochemical assays were conducted to validate transcriptome data.

Main Results:

  • Transcriptome data confirmed Spx's role in oxidative stress genes and identified novel Spx-controlled genes and metabolic pathways under peroxide stress.
  • While individual inactivation of new peroxide stress genes had minor effects, four of five genes inactivated in a ∆spxA1 background were essential for stress survival.
  • SpxA1 coordinates transcriptional changes that alter global metabolism and promote antioxidant production during peroxide stress.

Conclusions:

  • The study elucidates the comprehensive peroxide stress regulon in S. mutans.
  • It expands the repertoire of known oxidative stress genes in S. mutans.
  • It highlights the crucial role of SpxA1 in coordinating the bacterial response to oxidative stress.

More Related Videos

An Analytical Tool-box for Comprehensive Biochemical, Structural and Transcriptome Evaluation of Oral Biofilms Mediated by Mutans Streptococci11:09

An Analytical Tool-box for Comprehensive Biochemical, Structural and Transcriptome Evaluation of Oral Biofilms Mediated by Mutans Streptococci

Published on: January 25, 2011

18.2K
Measurements of Physiological Stress Responses in C. Elegans10:36

Measurements of Physiological Stress Responses in C. Elegans

Published on: May 21, 2020

15.1K

Related Concept Videos

Other Stress Responses in Bacteria01:30

Other Stress Responses in Bacteria

Bacteria have global regulatory systems that control several types of stress mechanisms. These include Pho regulon and the heat shock response, which are essential systems for environmental adaptation, such as nutrient limitation and proteotoxic stress. The Pho regulon and the heat shock response exemplify bacterial resilience, enabling rapid adaptation to fluctuating environmental conditions.Pho RegulonBacteria require phosphorus for essential cellular processes, including nucleic acid...
447
Oxygen Requirements and Growth Patterns01:29

Oxygen Requirements and Growth Patterns

Microorganisms exhibit diverse oxygen requirements and growth patterns driven by their metabolic strategies and environmental adaptations. Oxygen, while essential for many organisms, can also be toxic under certain conditions, shaping how microorganisms grow and survive.Oxygen Requirements of MicroorganismsMicroorganisms are classified based on their ability to use or tolerate oxygen:● Obligate aerobes like Mycobacterium tuberculosis need oxygen for energy production, as it serves as the...
1.6K
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...
404
Gene Regulation in Microbial Communities: Quorum Sensing01:28

Gene Regulation in Microbial Communities: Quorum Sensing

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,...
714
Gene Regulation During Sporulation01:17

Gene Regulation During Sporulation

Sporulation is a complex developmental process that allows certain Gram-positive bacteria, such as Bacillus subtilis and Clostridium species, to survive extreme environmental conditions. This process is tightly regulated by a series of signaling cascades and transcriptional controls, ensuring the formation of a highly resistant endospore.Sporulation is triggered by unfavorable conditions, such as nutrient depletion, and is governed by a phosphorelay system. One of the sensor kinases, such as...
535
Peroxisomes01:24

Peroxisomes

Peroxisomes are specialized organelles present in fungi, plant, and animal cells. It can vary in number, size, morphology, and activity depending on the type of tissue and the nutritional state of the cell. For example, cells with active lipid metabolism, such as adipocytes, neurons, and hepatocytes, have more peroxisomes than other cells in the body. Besides their primary role in breaking down complex organic molecules, peroxisomes can also synthesize specific macromolecules and participate in...
21.5K