Related Experiment Video

Updated: Feb 2, 2026

Culture of Small Colony Variant of Pseudomonas aeruginosa and Quantitation of its Alginate
09:06

Culture of Small Colony Variant of Pseudomonas aeruginosa and Quantitation of its Alginate

Published on: February 22, 2020

9.2K

Intraphagolysosomal conditions predispose to Staphylococcus epidermidis small colony variants persistence in

Agnieszka Magryś1, Kamil Deryło2, Agnieszka Bogut1

  • 1Chair and Department of Medical Microbiology, Medical University of Lublin, Lublin, Poland.

Plos One
|November 10, 2018
PubMed

Insights

Staphylococcus epidermidis small colony variants (SCV) persist within macrophages, aided by phagosomal acidification. Interferon-gamma (IFN-γ) effectively kills SCV by alkalizing phagosomes and increasing iNOS synthesis, controlling infection.

Area of Science:

  • Microbiology
  • Immunology
  • Cell Biology

Background:

  • Staphylococcus epidermidis small colony variants (SCV) are implicated in persistent biomaterial-associated infections.
  • SCV's ability to survive intracellularly within macrophages is a key factor in pathogenesis.
  • Understanding SCV-macrophage interactions is crucial for developing effective treatment strategies.

Purpose of the Study:

  • To determine the intracellular location of S. epidermidis SCV and wild-type (WT) strains within macrophages.
  • To investigate the effects of IFN-γ and rapamycin on SCV/WT intracellular survival, lysosome colocalization, and iNOS induction.
  • To elucidate the mechanisms by which IFN-γ controls S. epidermidis SCV infection.

Main Methods:

  • Intracellular localization of S. epidermidis SCV and WT strains in macrophages.
  • Assessment of phagosomal acidification using LysoTracker.
  • Measurement of inducible nitric oxide synthase (iNOS) induction.
  • Treatment with IFN-γ and rapamycin in THP-activated macrophages.

Main Results:

  • SCV survive and persist within macrophages, supported by phagosomal acidification.
  • IFN-γ treatment reduced LysoTracker-positive SCV-containing phagosomes, indicating SCV killing.
  • IFN-γ mediated SCV killing through phagosome alkalization and increased iNOS synthesis.
  • SCV were less potent iNOS inducers than WT strains, potentially aiding persistence.
  • Rapamycin reduced bacterial presence in acidic organelles but did not affect iNOS synthesis.

Conclusions:

  • IFN-γ effectively controls S. epidermidis WT and SCV infections in macrophages via distinct killing mechanisms.
  • SCV possess unique metabolic adaptations enabling survival within the hostile macrophage environment.
  • Targeting SCV intracellular survival mechanisms may offer new therapeutic avenues for biomaterial-associated infections.

More Related Videos

Culture of Macrophage Colony-stimulating Factor Differentiated Human Monocyte-derived Macrophages06:46

Culture of Macrophage Colony-stimulating Factor Differentiated Human Monocyte-derived Macrophages

Published on: June 30, 2016

31.0K
Development and Assessment of Intracellular Infection Models for Staphylococcus aureus08:32

Development and Assessment of Intracellular Infection Models for Staphylococcus aureus

Published on: January 17, 2025

1.3K

Related Concept Videos

Histone Variants at the Centromere02:30

Histone Variants at the Centromere

Histone variants are the histone proteins with structural and sequence variations. These variants may be regarded as “mutant” forms that replace their canonical histone counterparts in the nucleosomes. Specific post-translational modifications on the histone variants enable further chromatin complexity and regulate tissue-specific gene expression. The most common histone variants are from histone H2A, H2B, and linker histone H1 families. However, several variants of histone H3...
5.1K
Conditions on Early Earth02:06

Conditions on Early Earth

Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen into the primordial atmosphere. However, organisms with the characteristics of life were not initially present on earth. Scientists have used experimentation to determine how organisms evolved that could grow, reproduce, and maintain an internal environment.
101.5K
Classical Conditioning01:18

Classical Conditioning

Associative learning, a core principle in behavioral psychology, involves forming connections between events and facilitating learned responses. This concept is vividly illustrated by classical conditioning, a process extensively studied by the Russian physiologist Ivan Pavlov. Pavlov's pioneering research on dogs' digestive systems led to the discovery that behaviors can be learned through association, laying the groundwork for classical conditioning.
Ivan Pavlov observed that dogs...
2.2K
Conditions of Equilibrium01:28

Conditions of Equilibrium

Equilibrium refers to a state where a rigid body is not subjected to any translational or rotational motion. This state is achieved when the force and couple acting on a rigid body equal zero. When the system of external forces results in a net effect equivalent to zero, the rigid body is considered to be in equilibrium.
Internal forces are not considered for conditions of equilibrium because they occur in equal and opposite pairs within the body, effectively canceling each other. As a result,...
2.1K
Operant Conditioning01:21

Operant Conditioning

Operant conditioning, a key concept in behavioral psychology, involves using reinforcement and punishment to alter the likelihood of a behavior being repeated. B.F. introduced this type of conditioning. Skinner focused on voluntary behaviors and the consequences that follow them, influencing whether these behaviors will be strengthened or diminished.
Reinforcement in operant conditioning can be positive or negative, both of which serve to increase the likelihood of a behavior. Positive...
2.9K
Conditioned Taste Aversion01:14

Conditioned Taste Aversion

Conditioned taste aversion, also known as sauce béarnaise syndrome, is a phenomenon in which an individual develops an aversion to a certain food taste following a negative experience, typically illness. This form of aversion is a type of classical conditioning in which the taste of the food (conditioned stimulus, CS) is associated with the experience of illness (unconditioned stimulus, UCS).
A notable characteristic of conditioned taste aversion is that it often requires only a single...
607