Related Experiment Video

Updated: Feb 4, 2026

Determination of Mitochondrial Membrane Potential and Reactive Oxygen Species in Live Rat Cortical Neurons
09:56

Determination of Mitochondrial Membrane Potential and Reactive Oxygen Species in Live Rat Cortical Neurons

Published on: May 23, 2011

66.4K

Helicobacter pylori Outer Membrane Vesicles Protect the Pathogen From Reactive Oxygen Species of the Respiratory

Sujinna Lekmeechai1, Yu-Ching Su1, Marta Brant1

  • 1Clinical Microbiology and Molecular Pathology, Department of Translational Medicine, Faculty of Medicine, Lund University, Malmö, Sweden.

Frontiers in Microbiology
|September 25, 2018
PubMed

Insights

Outer membrane vesicles from Helicobacter pylori are enriched with catalase (KatA), an antioxidant enzyme. This OMV-associated KatA neutralizes harmful reactive oxygen species, aiding bacterial survival and immune evasion during infection.

Area of Science:

  • Microbiology
  • Immunology
  • Bacterial Pathogenesis

Background:

  • Outer membrane vesicles (OMVs) are crucial for the persistence of *Helicobacter pylori* infections.
  • OMVs harbor virulence factors that contribute to bacterial survival and pathogenesis.

Purpose of the Study:

  • To investigate the role of catalase (KatA) within *Helicobacter pylori* OMVs.
  • To determine if OMV-associated KatA contributes to immune evasion by counteracting host oxidative stress.

Main Methods:

  • Comparative analysis of KatA localization in OMVs versus bacterial cells.
  • Assay of OMV-dependent antioxidant activity against hydrogen peroxide (H₂O₂) and sodium hypochlorite (NaClO).
  • Assessment of bacterial survival under oxidative stress with and without functional OMV-associated KatA.

Main Results:

  • Catalase (KatA) is significantly enriched and surface-associated in OMVs compared to the parent bacterial cells.
  • OMVs exhibit potent antioxidant activity, neutralizing H₂O₂ and NaClO, thereby protecting surrounding bacteria from oxidative damage.
  • Deletion of the *katA* gene abolished the antioxidant capacity of OMVs and their protective effect on bacteria.

Conclusions:

  • The enrichment of antioxidative catalase (KatA) in *Helicobacter pylori* OMVs is a key mechanism for bacterial immune evasion.
  • OMV-mediated delivery of KatA is vital for neutralizing host-derived reactive oxygen species and ensuring bacterial survival.
Keywords:
H. pyloriKatAouter membrane vesiclesoxidative burstreactive oxygen species

More Related Videos

Production and Detection of Reactive Oxygen Species ROS in Cancers07:17

Production and Detection of Reactive Oxygen Species ROS in Cancers

Published on: November 21, 2011

71.1K
In Vivo Imaging of Reactive Oxygen Species in a Murine Wound Model06:40

In Vivo Imaging of Reactive Oxygen Species in a Murine Wound Model

Published on: November 17, 2018

11.7K

Related Concept Videos

Treating Helicobacter pylori in Peptic Ulcers: Antimicrobial Therapy01:16

Treating Helicobacter pylori in Peptic Ulcers: Antimicrobial Therapy

Helicobacter pylori, a resilient gram-negative bacterium, can thrive in the stomach's harsh, acidic environment. Infection with H. pylori leads to a cascade of events within the stomach lining. One of the critical disruptions caused by this bacterium is the interference with somatostatin production, a hormone responsible for regulating acid secretion. This interference tips the balance, escalating acid secretion and diminishing bicarbonate levels. This imbalance compromises the defensive...
1.3K
Porin Insertion in the Outer Mitochondrial Membrane01:12

Porin Insertion in the Outer Mitochondrial Membrane

Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
4.8K
Protein Transport to the Outer Chloroplast Membrane01:11

Protein Transport to the Outer Chloroplast Membrane

Chloroplast outer membrane proteins encoded by the nucleus are synthesized in the cytosol. Soon after synthesis, they bind cytosolic factors such as 14-3-3 protein and the Hsp70 chaperones that keep these precursors in an unfolded state until their translocation.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
2.4K
Fusion of Secretory Vesicles with the Plasma Membrane01:26

Fusion of Secretory Vesicles with the Plasma Membrane

Proteins and neurotransmitters in secretory vesicles can be released from a cell upon vesicle docking, priming, and fusion with the plasma membrane. Vesicles are docked and primed in preparation for the quick exocytosis of their contents in response to a stimulus. The fusion process is mainly carried out by a SNAP Receptor or SNARE complex, consisting of synaptobrevin, syntaxin-1, and SNAP-25.
In 1993, Jim Rothman proposed that the antiparallel pairing of vesicular and transmembrane SNAREs, or...
18.9K
What is a Species?01:17

What is a Species?

Overview
50.3K
Treatment for Pulmonary Arterial Hypertension: Oxygen Therapy for Respiratory Failure01:16

Treatment for Pulmonary Arterial Hypertension: Oxygen Therapy for Respiratory Failure

Oxygen therapy has emerged as a significant tool in enhancing the quality of life for patients suffering from pulmonary arterial hypertension (PAH). While this therapy has principally been studied on patients with significant hypoxemia, this therapeutic approach helps prevent potential organ damage and can be administered in the comfort of one's home.
Oxygen therapy is vital in increasing and maintaining blood oxygen levels in PAH patients. As a result, it aids in reducing fatigue,...
623