Related Experiment Video
Updated: Feb 6, 2026
09:33
Imaging Approaches to Assessments of Toxicological Oxidative Stress Using Genetically-encoded Fluorogenic Sensors
Published on: February 7, 2018
7.9K
Development of an oxidative stress sensor in live bacteria using the optimized HyPer2 protein
B Franco1, Felipe Padilla-Vaca2, Naurú Idalia Vargas-Maya3
1Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, 36050, Guanajuato, Gto, Mexico. bfranco@ugto.mx.
Antonie Van Leeuwenhoek
|August 13, 2018
Summary
Researchers developed a whole-cell reporter system using HyPer2 protein in Escherichia coli to monitor hydrogen peroxide (H2O2) levels in vivo. This system allows for tracking oxidative stress and cellular responses without direct analytical measurements.
Area of Science:
- Microbiology
- Cellular Biology
- Biochemistry
Background:
- Oxidative stress is a critical cellular process with implications for organismal health.
- Quantifying oxidative damage and distinguishing oxidant sources within cells presents analytical challenges.
- Existing methods struggle to differentiate between primary oxidants and secondary reactive oxygen species (ROS) generated by cellular metabolism.
Purpose of the Study:
- To develop and validate a whole-cell reporter system for in vivo monitoring of hydrogen peroxide (H2O2) in Escherichia coli.
- To assess the utility of the optimized HyPer2 protein as a biosensor for oxidative stress in bacterial cells.
- To demonstrate the system's capability in tracing intracellular oxidative events.
Main Methods:
- Engineered two HyPer2 expression systems in E. coli: one IPTG-inducible and one oxidative stress-responsive promoter-controlled.
- Utilized flow cytometry to analyze HyPer2 fluorescence in bacterial cells following H2O2 exposure.
- Applied the system to trace the oxidative capacity of Toluidine Blue O within bacterial cells.
Main Results:
- The HyPer2 reporter system successfully monitored the transcriptional effects of H2O2 in vivo in E. coli.
- Hydrogen peroxide pulses generated a distinct, concentration-dependent fluorescence signature within bacterial cells.
- The system demonstrated that H2O2 exposure can be traced through intracellular pathways.
- HyPer2 functions as a viable bacterial sensor for H2O2, albeit with lower sensitivity compared to eukaryotic systems or purified protein.
Conclusions:
- The developed whole-cell HyPer2 reporter system provides a novel method for detecting and tracing H2O2 in E. coli.
- This system expands the toolkit for studying cellular stress responses and redox imbalances in bacteria.
- The proof-of-concept demonstrated its application in evaluating the oxidative potential of compounds like Toluidine Blue O.
Related Concept Videos
01:30Other Stress Responses in Bacteria
420
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...
420
01:29Cytoskeletal Proteins in Bacteria
4.3K
Bacterial cells were initially considered simple, randomly organized structures lacking a cytoskeleton. However, the discovery of cytoskeleton homologs in bacteria led to the change of this opinion. Bacterial cytoskeletal filaments regulate the cell shape, cell polarity, cell division, and partitioning of plasmids during cell division. It was later discovered that bacterial cytoskeletal proteins, mainly actin and tubulin homologs, are diverse compared to their eukaryotic counterparts. On the...
4.3K
03:14Oxidation Numbers
42.9K
In redox reactions, the transfer of electrons occurs between reacting species. Electron transfer is described by a hypothetical number called the oxidation number (or oxidation state). It represents the effective charge of an atom or element, which is assigned using a set of rules.
42.9K
02:45Responses to Heat and Cold Stress
14.9K
Every organism has an optimum temperature range within which healthy growth and physiological functioning can occur. At the ends of this range, there will be a minimum and maximum temperature that interrupt biological processes.
14.9K
01:19Protein Dynamics in Living Cells
2.7K
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
2.7K
01:15Pyruvate Oxidation
169.0K
After glycolysis, the charged pyruvate molecules enter the mitochondria via active transport and undergo three enzymatic reactions. These reactions ensure that pyruvate can enter the next metabolic pathway so that energy stored in the pyruvate molecules can be harnessed by the cells.
First, the enzyme pyruvate dehydrogenase removes the carboxyl group from pyruvate and releases it as carbon dioxide. The stripped molecule is then oxidized and releases electrons, which are then picked up by NAD+...
First, the enzyme pyruvate dehydrogenase removes the carboxyl group from pyruvate and releases it as carbon dioxide. The stripped molecule is then oxidized and releases electrons, which are then picked up by NAD+...
169.0K