Related Experiment Video

Updated: Jul 5, 2026

A Rapid Image-based Bacterial Virulence Assay Using Amoeba
05:22

A Rapid Image-based Bacterial Virulence Assay Using Amoeba

Published on: June 27, 2018

Pseudomonas aeruginosa utilises its type III secretion system to kill the free-living amoeba Acanthamoeba castellanii

Hadi Abd1, Bengt Wretlind, Amir Saeed

  • 1Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institute, Stockholm, Sweden.

The Journal of Eukaryotic Microbiology
|May 8, 2008
PubMed

Insights

Pseudomonas aeruginosa uses type III secretion system (TTSS) toxins to kill Acanthamoeba. This bacterial defense mechanism is crucial for its survival against eukaryotic predators in the environment.

Area of Science:

  • Microbiology
  • Pathogen-Host Interactions
  • Cell Biology

Background:

  • Pseudomonas aeruginosa is a common bacterium and opportunistic pathogen.
  • It employs survival strategies like microcolony formation and toxin production via the type III secretion system (TTSS) to evade predators.
  • Eukaryotic predators like macrophages and phagocytes pose a threat to bacterial survival.

Purpose of the Study:

  • To investigate the interaction between TTSS effector proteins of P. aeruginosa PA103 and Acanthamoeba castellanii.
  • To determine the role of TTSS in P. aeruginosa's survival against eukaryotic predation.

Main Methods:

  • Co-cultivation of P. aeruginosa PA103 with Acanthamoeba castellanii.
  • Viable count assays.
  • Eosin staining.
  • Electron microscopy.
  • Apoptosis assays.
  • Statistical analysis.

Main Results:

  • P. aeruginosa PA103, through its TTSS effector proteins (ExoU, ExoS, ExoT, ExoY), induced necrosis and apoptosis in Acanthamoeba castellanii, leading to its death.
  • Acanthamoeba cultured alone or with P. aeruginosa lacking these TTSS effectors survived.
  • This highlights the critical role of TTSS effectors in bacterial survival against eukaryotic predators.

Conclusions:

  • The type III secretion system (TTSS) and its effector proteins are essential for Pseudomonas aeruginosa's survival in the environment.
  • TTSS effectors enable P. aeruginosa to eliminate eukaryotic predators like Acanthamoeba.
  • This mechanism supports P. aeruginosa's strategy as a strict extracellular bacterium.

More Related Videos

Generation of In-Frame Gene Deletion Mutants in Pseudomonas aeruginosa and Testing for Virulence Attenuation in a Simple Mouse Model of Infection08:34

Generation of In-Frame Gene Deletion Mutants in Pseudomonas aeruginosa and Testing for Virulence Attenuation in a Simple Mouse Model of Infection

Published on: January 8, 2020

Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants11:35

Replication of the Ordered, Nonredundant Library of Pseudomonas aeruginosa strain PA14 Transposon Insertion Mutants

Published on: May 4, 2018

Related Concept Videos

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,...
Gram-negative Bacterial Protein Secretion Systems01:17

Gram-negative Bacterial Protein Secretion Systems

Gram-negative bacteria utilize sophisticated protein secretion systems to transport proteins across their double-membrane envelope into the extracellular environment or host cells. Based on their mechanism of action, these systems are classified into one-step and two-step pathways.One-Step Secretion Systems (Types I, III, IV, and VI)One-step secretion systems bypass the periplasm entirely, forming a continuous channel that spans both the inner and outer membranes:Type I Secretion System (T1SS):...
Amebiasis01:28

Amebiasis

Entamoeba histolytica, a protozoan parasite, is responsible for intestinal and extraintestinal amebiasis. Though a significant proportion of infections remain asymptomatic, approximately 50 million individuals annually are estimated to present with clinical disease, resulting in up to 100,000 deaths globally. The disease burden is disproportionately high in regions with lower socioeconomic status, such as parts of India, Africa, Mexico, and Latin America.Etiology and TransmissionThe infective...
Colonisation of Pathogens01:25

Colonisation of Pathogens

Pathogen colonization of host tissues is a critical step in the development of infectious diseases. Various pathogenic microorganisms, including bacteria, fungi, viruses, and protozoa, have evolved complex strategies to attach to, invade, and persist within host environments. These mechanisms enable pathogens to establish infections, evade immune responses, and resist antimicrobial treatments.Attachment to Host CellsIn bacteria, colonization typically begins with adherence to host epithelial...
Diversity of Protists II01:27

Diversity of Protists II

Alveolates are a group of organisms recognized by the presence of alveoli, which are cytoplasmic sacs located beneath the cell membrane. While their function remains uncertain, alveoli may help regulate water balance by controlling how much water enters and leaves the cell. In dinoflagellates, these structures may serve as armor plates. There are three major types of alveolates: ciliates, which move using cilia; dinoflagellates, which use flagella for movement; and apicomplexans, which are...
Diversity of Protists IV01:27

Diversity of Protists IV

Amoebozoa represent a diverse group of terrestrial and aquatic protists that utilize lobe-shaped pseudopodia for locomotion and feeding. This characteristic differentiates them from the Rhizaria, which possess threadlike pseudopodia. The primary classifications within Amoebozoa include gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence indicates that Amoebozoa diverged from a lineage that ultimately gave rise to fungi and animals.Gymnamoebas and...